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Xu C, Bai X, Ruan D, Zhang C. Comparative finite element analysis of posterior short segment fixation constructs with or without intermediate screws in the fractured vertebrae for the treatment of type a thoracolumbar fracture. Comput Methods Biomech Biomed Engin 2024; 27:1398-1409. [PMID: 37553841 DOI: 10.1080/10255842.2023.2243360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 07/18/2023] [Accepted: 07/27/2023] [Indexed: 08/10/2023]
Abstract
Six-screw short-segment posterior fixation for thoracolumbar fractures, which involves intermediate screws at the fractured vertebrae has been proposed to reduce the rates of kyphosis recurrence and implant failure. Yet, little is known about the mechanisms and biomechanical responses by which intermediate screws at the fracture vertebrae enhance fixation strength. The objective of this study was to investigate the biomechanical properties that are associated with the augmentation of intermediate screws in relation to the severity of type A thoracolumbar fracture using finite element analysis. Short-segment stabilization models with or without augmentation screws at fractured vertebrae were established based on finite element model of moderate compressive fractures, severe compressive fractures and burst fractures. The spinal stiffness, stresses at the implanted hardware, and axial displacement of the bony defect were measured and compared under mechanical loading conditions. All six-screw stabilization showed a decreased range of motion in extension, lateral bending, and axial rotation compared to the traditional four-screw fixation models. Burst thoracolumbar fracture benefited more from augmentation of intermediate screws at the fracture vertebrae. The stress of the rod in six-screw models increased while decreased that of pedicle screws. Our results suggested that patients with more unstable fractures might achieve greater benefits from augmentation of intermediate screws at the fracture vertebrae. Augmentation of intermediate screws at the fracture vertebrae is recommended for patients with higher wedge-shaped or burst fractures to reduce the risk of hardware failure and postoperative re-collapse of injured vertebrae.
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Affiliation(s)
- Cheng Xu
- Department of Orthopaedic Surgery, The Sixth Medical Center, General Hospital of PLA, Beijing, China
| | - Xuedong Bai
- Department of Orthopaedic Surgery, The Sixth Medical Center, General Hospital of PLA, Beijing, China
| | - Dike Ruan
- Department of Orthopaedic Surgery, The Sixth Medical Center, General Hospital of PLA, Beijing, China
| | - Chao Zhang
- Department of Orthopaedic Surgery, The Sixth Medical Center, General Hospital of PLA, Beijing, China
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Meisterhans M, Hagel V, Spirig JM, Fasser MR, Farshad M, Widmer J. The Biomechanics of the Transpedicular Endoscopic Approach. Spine (Phila Pa 1976) 2024; 49:1052-1058. [PMID: 37942817 PMCID: PMC11232940 DOI: 10.1097/brs.0000000000004871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Accepted: 10/31/2023] [Indexed: 11/10/2023]
Abstract
STUDY DESIGN Biomechanical cadaveric study. OBJECTIVE The goal of this study was to analyze the effects of an endoscopic transpedicular approach with different drill diameters (6 and 8 mm) and compare them with the intact native side. In addition, the influence of bone quality on the resistance of the pedicle was investigated. SUMMARY OF BACKGROUND DATA Clinical studies have repeatedly highlighted the benefits of endoscopic transpedicular decompression for downmigrated lumbar disc herniations. However, the biomechanical effects on pedicle stability have not been studied up to now. MATERIALS AND METHODS Twenty-four vertebras originating from four fresh-frozen cadavers were tested under uniaxial compression load in a ramp-to-failure test: (1) the tunneled pedicle on one side, and (2) the native pedicle on the other side. Twelve lumbar vertebrae were assigned to drill diameter of 6 mm and the other 12 to diameter of 8 mm. RESULTS The median ratio of sustained force for the operated side compared with the intact contralateral side is equal to 74% (63-88) for both drill diameters combined. An 8 mm transpedicular approach recorded an axial resistance of 77% (60-88) compared with the intact contralateral side ( P =0.002). A 6 mm approach resulted in an axial resistance of 72% (66-84) compared with the intact opposite side ( P =0.01). No significant difference between the two different drill diameters was recorded ( P =1). For all three subgroups (intact, 8 mm, 6 mm) the Hounsfield units-values and the absolute resistance force showed significant correlations (intact: ρ=0.859; P <0.001; 8 mm: ρ=0.902; P <0.001; 6 mm: ρ=0.835; P <0.001). CONCLUSION The transpedicular approach significantly reduces the axial resistance force of the pedicle, which may lead to pedicle fracture. Bone quality correlated positively with the absolute resistance force of the pedicle, whereas the influence of the drill hole diameter plays only a limited role.
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Affiliation(s)
- Michel Meisterhans
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Vincent Hagel
- University Spine Center Zurich, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- Spine Center, Asklepios Klinik Lindau, Lindau, Germany
| | - José M. Spirig
- University Spine Center Zurich, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Marie-Rosa Fasser
- Institute of Biomechanics, Balgrist Campus, ETH Zurich, Zurich, Switzerland
- Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Mazda Farshad
- Department of Orthopedics, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
- University Spine Center Zurich, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
| | - Jonas Widmer
- Institute of Biomechanics, Balgrist Campus, ETH Zurich, Zurich, Switzerland
- Spine Biomechanics, Department of Orthopedic Surgery, Balgrist University Hospital, University of Zurich, Zurich, Switzerland
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Vienney C, Hambli R, De Leacy R, Cornelis FH. Effect of cement volume on biomechanical response of a spine segment treated with a PEEK polymer implant: a finite element comparative study with vertebroplasty. Front Bioeng Biotechnol 2024; 12:1399851. [PMID: 38919381 PMCID: PMC11196805 DOI: 10.3389/fbioe.2024.1399851] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2024] [Accepted: 05/23/2024] [Indexed: 06/27/2024] Open
Abstract
In the current study, a 3D finite element study was performed to investigate the biomechanical response of an osteoporotic spine segment treated with a novel transpedicular implant (V-STRUT©, Hyprevention, France) made of PEEK (polyetheretherketone) material combined with either injections of 2, 3, 4, 5 and 6 cc of cement. The objective was to assess numerically the biomechanical performance of the implant in combination with different doses of the injected bone cement and to compare its performance with the gold standard vertebroplasty (VP) technique. A female (69 yo) was selected and a 3D finite element model of an osteoporotic spine segment was built based on a Computed Tomography (CT) scan performed from T12 to L2 with corresponding intervertebral discs and ligaments. A heterogeneous distribution of bone material properties was assigned to the bone using grey scale levels. Bilateral ellipsoid geometries of the inserted cement were retained for the V-STRUT and VP models based on experimental observation performed on different patients treated with the V-STRUT device. The current study demonstrated an optimal dose of 4 cc of bilaterally injected cement for the V-STRUT and VP techniques to restore the treated segment and confirmed that the V-STRUT device in combination with bone cement is superior to VP alone in establishing the normal stiffness and in reducing the applied stress to the immediately adjacent vertebral levels.
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Affiliation(s)
| | - Ridha Hambli
- University of Orléans, University of Tours, INSA CVL, LaMé, Orléans, France
| | - Reade De Leacy
- Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - François H. Cornelis
- Memorial Sloan Kettering Cancer Center and Weill Cornell Medical College, Radiology Department of Radiology, New York, NY, United States
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Gruber G, Nicolini LF, Ribeiro M, Lerchl T, Wilke HJ, Jaramillo HE, Senner V, Kirschke JS, Nispel K. Comparative FEM study on intervertebral disc modeling: Holzapfel-Gasser-Ogden vs. structural rebars. Front Bioeng Biotechnol 2024; 12:1391957. [PMID: 38903189 PMCID: PMC11188472 DOI: 10.3389/fbioe.2024.1391957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 04/29/2024] [Indexed: 06/22/2024] Open
Abstract
Introduction: Numerical modeling of the intervertebral disc (IVD) is challenging due to its complex and heterogeneous structure, requiring careful selection of constitutive models and material properties. A critical aspect of such modeling is the representation of annulus fibers, which significantly impact IVD biomechanics. This study presents a comparative analysis of different methods for fiber reinforcement in the annulus fibrosus of a finite element (FE) model of the human IVD. Methods: We utilized a reconstructed L4-L5 IVD geometry to compare three fiber modeling approaches: the anisotropic Holzapfel-Gasser-Ogden (HGO) model (HGO fiber model) and two sets of structural rebar elements with linear-elastic (linear rebar model) and hyperelastic (nonlinear rebar model) material definitions, respectively. Prior to calibration, we conducted a sensitivity analysis to identify the most important model parameters to be calibrated and improve the efficiency of the calibration. Calibration was performed using a genetic algorithm and in vitro range of motion (RoM) data from a published study with eight specimens tested under four loading scenarios. For validation, intradiscal pressure (IDP) measurements from the same study were used, along with additional RoM data from a separate publication involving five specimens subjected to four different loading conditions. Results: The sensitivity analysis revealed that most parameters, except for the Poisson ratio of the annulus fibers and C01 from the nucleus, significantly affected the RoM and IDP outcomes. Upon calibration, the HGO fiber model demonstrated the highest accuracy (R2 = 0.95), followed by the linear (R2 = 0.89) and nonlinear rebar models (R2 = 0.87). During the validation phase, the HGO fiber model maintained its high accuracy (RoM R2 = 0.85; IDP R2 = 0.87), while the linear and nonlinear rebar models had lower validation scores (RoM R2 = 0.71 and 0.69; IDP R2 = 0.86 and 0.8, respectively). Discussion: The results of the study demonstrate a successful calibration process that established good agreement with experimental data. Based on our findings, the HGO fiber model appears to be a more suitable option for accurate IVD FE modeling considering its higher fidelity in simulation results and computational efficiency.
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Affiliation(s)
- Gabriel Gruber
- Department of Diagnostic and Interventional Neuroradiology, School of Medicine and Health, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Luis Fernando Nicolini
- Department of Mechanical Engineering, Federal University of Santa Maria, Av. Santa Maria, Brazil
| | - Marx Ribeiro
- Department for Orthopedics, Trauma and Reconstructive Surgery, University Hospital RWTH Aachen, Aachen, Germany
- Department of Mechanical Engineering, Federal University of Santa Catarina, Florianópolis, Brazil
| | - Tanja Lerchl
- Department of Diagnostic and Interventional Neuroradiology, School of Medicine and Health, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
- Associate Professorship of Sport Equipment and Sport Materials, School of Engineering and Design, Technical University of Munich, Garching, Germany
| | - Hans-Joachim Wilke
- Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre Ulm, University of Ulm, Ulm, Germany
| | | | - Veit Senner
- Associate Professorship of Sport Equipment and Sport Materials, School of Engineering and Design, Technical University of Munich, Garching, Germany
| | - Jan S. Kirschke
- Department of Diagnostic and Interventional Neuroradiology, School of Medicine and Health, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
| | - Kati Nispel
- Department of Diagnostic and Interventional Neuroradiology, School of Medicine and Health, Klinikum rechts der Isar, Technical University of Munich, Munich, Germany
- Associate Professorship of Sport Equipment and Sport Materials, School of Engineering and Design, Technical University of Munich, Garching, Germany
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Kostenko E, Stonkus R, Šengaut J, Višniakov N, Maknickas A. Quantitative Analysis of Stress-Stretch Curves in Canine Lumbar Vertebrae Using Modified Logistic Functions. Bioengineering (Basel) 2024; 11:516. [PMID: 38790381 PMCID: PMC11117871 DOI: 10.3390/bioengineering11050516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 05/03/2024] [Accepted: 05/15/2024] [Indexed: 05/26/2024] Open
Abstract
BACKGROUND The mechanical characteristics of bone are crucial for comprehending its functionality and response to different load conditions, which are essential for advancing medical treatments, implants, and prosthetics. By employing mathematical modeling to analyze the mechanical properties of bone, we can assess stress and deformation under both normal and abnormal conditions. This analysis offers valuable perspectives on potential fracture risks, the effects of diseases, and the effectiveness of various treatments. Therefore, researchers are attempting to find an adequate mathematical description of the mechanical properties of bone. METHODS Experimental stress-stretch external loading curves were obtained through investigations of canine vertebrae. The obtained experimental curves were fitted using the SciPy Python library with a slightly modified logistic function (logistic function plus additional const). RESULTS The resulting coefficient of determination R2 (R squared) for most curves was near 0.999, indicating that an appropriate fitting function was selected for the description of the experimental stress-stretch curves. CONCLUSIONS The stress-stretch behavior of canine vertebrae can be described using a logistic function modified by adding additional parameters for the most accurate fitting results.
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Affiliation(s)
- Ernest Kostenko
- Department of Veterinary, Faculty of Agrotechnologies, Vilniaus Kolegija/Higher Education Institution, 08105 Vilnius, Lithuania
| | - Rimantas Stonkus
- Department of Mechatronics, Robotics and Digital Manufacturing, Vilnius Gediminas Technical University, 10105 Vilnius, Lithuania
| | | | - Nikolaj Višniakov
- Institute of Mechanical Science, Vilnius Gediminas Technical University, 10105 Vilnius, Lithuania
| | - Algirdas Maknickas
- Institute of Mechanical Science, Vilnius Gediminas Technical University, 10105 Vilnius, Lithuania
- Department of Biomechanical Engineering, Vilnius Gediminas Technical University, 10105 Vilnius, Lithuania
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Panico M, Chande RD, Lindsey DP, Maria Tobia Villa T, Yerby SA, Brayda-Bruno M, Bassani T, Polly DW, Galbusera F. High-Demand Spinal Deformity With Multi-Rod Constructs and Porous Fusion/Fixation Implants: A Finite Element Study. Global Spine J 2024; 14:1328-1336. [PMID: 36421053 PMCID: PMC11289527 DOI: 10.1177/21925682221141874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
STUDY DESIGN Basic science (finite element analysis). OBJECTIVES Pedicle subtraction osteotomy (PSO) at L5 is an effective treatment for sagittal imbalance, especially in select cases of patients showing kyphosis with the apex at L4-L5 but has been scarcely investigated. The aim of this study was to simulate various "high-demand" instrumentation approaches, including varying numbers of rods and sacropelvic implants, for the stabilization of a PSO at L5. METHODS A finite element model of T10-pelvis was modified to simulate posterior fixation with pedicle screws and rods from T10 to S1, alone or in combination with an L5 PSO. Five additional configurations were then created by employing rods and novel porous fusion/fixation implants across the sacroiliac joints, in varying numbers. All models were loaded using pure moments of 7.5 Nm in flexion-extension, lateral bending, and axial rotation. RESULTS The osteotomy resulted in a general increase in motion and stresses in posterior rods and S1 pedicle screws. When the number of rods was varied, three- and four-rod configurations were effective in limiting the maximal rod stresses; values approached those of posterior fixation with no osteotomy. Maximum stresses in the accessory rods were similar to or less than those observed in the primary rods. Multiple sacropelvic implants were effective in reducing range of motion, particularly of the SIJ. CONCLUSIONS Multi-rod constructs and sacropelvic fixation generally reduced maximal implant stresses and motion in comparison with standard posterior fixation, suggesting a reduced risk of rod breakage and increased joint stability, respectively, when a high-demand construct is utilized for the correction of sagittal imbalance.
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Affiliation(s)
- Matteo Panico
- IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”, Politecnico di Milano, Milan, Italy
| | | | | | - Tomaso Maria Tobia Villa
- IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
- Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”, Politecnico di Milano, Milan, Italy
| | | | | | - Tito Bassani
- IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
| | - David W. Polly
- Department of Orthopedic Surgery, University of Minnesota, Minnesota, MN, USA
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Wang X, Liu W, Zhao Y, Ma P. The impact of disc degeneration on the dynamic characteristics of the lumbar spine: a finite element analysis. Front Bioeng Biotechnol 2024; 12:1384187. [PMID: 38751866 PMCID: PMC11094277 DOI: 10.3389/fbioe.2024.1384187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Accepted: 04/17/2024] [Indexed: 05/18/2024] Open
Abstract
The dynamics of disc degeneration was analyzed to determine the effect of disc degeneration at the L4-L5 segment on the dynamic characteristics of the total lumbar spine. A three-dimensional nonlinear finite element model of the L1-S1 normal lumbar spine was constructed and validated. This normal model was then modified to construct two degeneration models with different degrees of degeneration (mild, moderate) at the L4-L5 level. Modal analysis, harmonic response analysis, and transient dynamics analysis were performed on the total lumbar spine when experiencing following compressive loading (500 N). As the degree of disc degeneration increased, the vibration patterns corresponding to the first three orders of the model's intrinsic frequency were basically unchanged, with the first order being in the left-right lateral bending direction, the second order being in the forward-flexion and backward-extension direction, and the third order being in the axial stretching direction. The nucleus pulposus pressure peaks corresponding to the first order intrinsic frequency for the harmonic response analysis are all on the right side of the model, with sizes of 0.053 MPa, 0.061 MPa, and 0.036 MPa, respectively; the nucleus pulposus pressure peaks corresponding to the second order intrinsic frequency are all at the rear of the model, with sizes of 0.13 MPa, 0.087 MPa, and 0.11 MPa, respectively; and the nucleus pulposus pressure peaks corresponding to the third order intrinsic frequency are all at the front of the model, with sizes of 0.19 MPa, 0.22 MPa, and 0.22 MPa, respectively. The results of the transient analysis indicated that over time, the response curves of the healthy model, the mild model, and the moderate model all exhibited cyclic response characteristics. Intervertebral disc degeneration did not adversely affect the vibration characteristics of the entire lumbar spine system. Intervertebral disc degeneration significantly altered the dynamics of the degenerative segments and their neighboring normal segments. The process of disc degeneration gradually shifted the load from the nucleus pulposus to the annulus fibrosus when the entire lumbar spine was subjected to the same vibratory environment.
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Affiliation(s)
- Xue Wang
- The Sixth Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Wei Liu
- The Affiliated Tumor Hospital of Xinjiang Medical University, Urumqi, China
| | - Yaqiong Zhao
- The Sixth Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Pengcheng Ma
- Shandong Public Health Clinical Center, Shandong University, Jinan, China
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Turbucz M, Pokorni AJ, Hajnal B, Koch K, Szoverfi Z, Varga PP, Lazary A, Eltes PE. The biomechanical effect of lumbopelvic distance reduction on reconstruction after total sacrectomy: a comparative finite element analysis of four techniques. Spine J 2024:S1529-9430(24)00195-5. [PMID: 38688331 DOI: 10.1016/j.spinee.2024.04.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 04/11/2024] [Accepted: 04/23/2024] [Indexed: 05/02/2024]
Abstract
BACKGROUND CONTEXT Following total sacrectomy, lumbopelvic reconstruction is essential to restore continuity between the lumbar spine and pelvis. However, to achieve long-term clinical stability, bony fusion between the lumbar spine and the pelvic ring is crucial. Reduction of the lumbopelvic distance can promote successful bony fusion. Although many lumbopelvic reconstruction techniques (LPRTs) have been previously analyzed, the biomechanical effect of lumbopelvic distance reduction (LPDR) has not been investigated yet. PURPOSE To evaluate and compare the biomechanical characteristics of four different LPRTs while considering the effect of LPDR. STUDY DESIGN/SETTING A comparative finite element (FE) study. METHODS The FE models following total sacrectomy were developed to analyze four different LPRTs, with and without LPDR. The closed-loop reconstruction (CLR), the sacral-rod reconstruction (SRR), the four-rod reconstruction (FRR), and the improved compound reconstruction (ICR) techniques were analyzed in flexion, extension, lateral bending, and axial rotation. Lumbopelvic stability was assessed through the shift-down displacement and the relative sagittal rotation of L5, while implant safety was evaluated based on the stress state at the bone-implant interface and within the rods. RESULTS Regardless of LPDR, both the shift-down displacement and relative sagittal rotation of L5 consistently ranked the LPRTs as ICR CONCLUSIONS LPDR significantly improved both lumbopelvic stability and implant safety in all reconstruction techniques after total sacrectomy. LPDR reduced the shift-down displacement of L5, the relative sagittal rotation of L5, and the stress values at the bone-implant interface. Furthermore, in the ICR and SRR techniques, LPDR decreased the peak stress values within the rods. All four investigated LPRTs demonstrated suitability for lumbopelvic reconstruction, with the ICR technique exhibiting the highest lumbopelvic stiffness. CLINICAL SIGNIFICANCE LPDR creates a biomechanically advantageous environment following total sacrectomy; therefore, it has the potential to impact the design of custom-made 3D-printed or traditional LPRTs. However, to confirm the findings of the current FE study, long-term clinical trials are recommended.
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Affiliation(s)
- Mate Turbucz
- School of PhD Studies, Semmelweis University, Üllői Str. 26, Budapest, Hungary; In Silico Biomechanics Laboratory, National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary
| | - Agoston Jakab Pokorni
- School of PhD Studies, Semmelweis University, Üllői Str. 26, Budapest, Hungary; In Silico Biomechanics Laboratory, National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary
| | - Benjamin Hajnal
- School of PhD Studies, Semmelweis University, Üllői Str. 26, Budapest, Hungary; In Silico Biomechanics Laboratory, National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary
| | - Kristof Koch
- School of PhD Studies, Semmelweis University, Üllői Str. 26, Budapest, Hungary; National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary
| | - Zsolt Szoverfi
- National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary
| | - Peter Pal Varga
- National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary
| | - Aron Lazary
- National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary; Department of Spine Surgery, Department of Orthopaedics, Semmelweis University, Üllői Str. 78/b, Budapest, Hungary
| | - Peter Endre Eltes
- In Silico Biomechanics Laboratory, National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary; National Center for Spinal Disorders, Királyhágó Str. 1-3, Budapest, Hungary; Department of Spine Surgery, Department of Orthopaedics, Semmelweis University, Üllői Str. 78/b, Budapest, Hungary.
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Nazari AR. Simulation of cancer progression in bone by a virtual thermal flux with a case study on lumbar vertebrae with multiple myeloma. Med Eng Phys 2024; 126:104147. [PMID: 38621839 DOI: 10.1016/j.medengphy.2024.104147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Revised: 02/15/2024] [Accepted: 03/09/2024] [Indexed: 04/17/2024]
Abstract
BACKGROUND Two main problems examining the mechanism of cancer progression in the tissues using the computational models are lack of enough knowledge on the effective factors for such events in vivo environments and lack of specific parameters in the available computational models to simulate such complicated reactions. METHODS In this study, it was tried to simulate the progression of cancerous lesions in the bone tissues by an independent parameter from the anatomical and physiological characteristics of the tissues, so to degrade the orthotropic mechanical properties of the bone tissues, a virtual temperature was determined to be used by a well-known framework for simulation of damages in the composite materials. First, the reliability of the FE model to simulate hyperelastic response in the intervertebral discs (IVDs) and progressive failure in the bony components were verified by simulation of some In-Vitro tests, available in the literature. Then, the progression of the osteolytic damage was simulated in a clinical case with multiple myeloma in the lumbar vertebrae. RESULTS The FE model could simulate stress-shielding and diffusion of lesion in the posterior elements of the damaged vertebra which led to spinal stenosis. The load carrying shares associated with the anterior half and the posterior half of the examined vertebral body and the posterior elements were estimated equal to 41 %, 47 % and 12 %, respectively for the intact condition, that changed to 14 %, 16 % and 70 %, when lesion occupied one third of the vertebral body. CONCLUSION Correlation of the FE results with the deformation shapes, observed in the MRIs for the clinical case study, indicated appropriateness of the procedure, proposed for simulation of the progressive osteolytic damage in the vertebral segments. The future studies may follow simulation of tumor growth for various metastatic tissues using the method, established here.
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Affiliation(s)
- A R Nazari
- Department of Civil Engineering, Technical & Vocational University, Tehran, Iran; Biomechanics Research Lab, Technical & Vocational University, Tehran, Iran.
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Xi Z, Xie Y, Sun S, Wang N, Chen S, Wang G, Li J. IVD fibrosis and disc collapse comprehensively aggravate vertebral body disuse osteoporosis and zygapophyseal joint osteoarthritis by posteriorly shifting the load transmission pattern. Comput Biol Med 2024; 170:108019. [PMID: 38325217 DOI: 10.1016/j.compbiomed.2024.108019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 12/26/2023] [Accepted: 01/22/2024] [Indexed: 02/09/2024]
Abstract
BACKGROUND Disuse is a typical phenotype of osteoporosis, but the underlying mechanism has yet to be identified in elderly patients. Disc collapse and intervertebral disc (IVD) fibrosis are two main pathological changes in IVD degeneration (IDD) progression, given that these changes affect load transmission patterns, which may lead to disuse osteoporosis of vertebral bodies and zygapophyseal joint (ZJ) osteoarthritis (ZJOA) biomechanically. METHODS Clinical data from 59 patients were collected retrospectively. Patient vertebral bony density, ZJOA grade, and disc collapse status were judged via CT. The IVD fibrosis grade was determined based on the FA measurements. Regression analyses identified potential independent risk factors for osteoporosis and ZJOA. L4-L5 numerical models with and without disc collapse and IVD fibrosis were constructed; stress distributions on the bony endplate (BEP) and zygapophyseal joint (ZJ) cartilages were computed in models with and without disc collapse and IVD fibrosis. RESULTS A significantly lower disc height ratio and significantly greater FA were recorded in patients with ZJOA. A significant correlation was observed between lower HU values and two parameters related to IDD progression. These factors were also proven to be independent risk factors for both osteoporosis and ZJOA. Correspondingly, compared to the intact model without IDD. Lower stress on vertebral bodies and greater stress on ZJOA can be simultaneously recorded in models of disc collapse and IVD fibrosis. CONCLUSIONS IVD fibrosis and disc collapse simultaneously aggravate vertebral body disuse osteoporosis and ZJOA by posteriorly shifting the load transmission pattern.
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Affiliation(s)
- Zhipeng Xi
- Department of Orthopedics, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, Jiangsu Province, PR China; Department of Orthopedics, Traditional Chinese Medicine Hospital of Ili Kazak Autonomous Prefecture, Yining, 835000, Xinjiang Uighur Autonomous Region, PR China
| | - Yimin Xie
- Department of Orthopedics, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, Jiangsu Province, PR China
| | - Shenglu Sun
- Department of Imaging, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, Jiangsu Province, PR China
| | - Nan Wang
- Department of Orthopedics, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, Jiangsu Province, PR China
| | - Shuang Chen
- Department of Orthopedics, Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, Jiangsu Province, PR China
| | - Guoyou Wang
- Department of Orthopedics, Luzhou Key Laboratory of Orthopedic Disorders, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, NO.182, Chunhui Road, Longmatan District, Luzhou, Sichuan Province, 646000, PR China.
| | - Jingchi Li
- Department of Orthopedics, Luzhou Key Laboratory of Orthopedic Disorders, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, NO.182, Chunhui Road, Longmatan District, Luzhou, Sichuan Province, 646000, PR China.
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Huang F, Huang G, Jia J, Lu S, Li J. Intraoperative capsule protection can reduce the potential risk of adjacent segment degeneration acceleration biomechanically: an in silico study. J Orthop Surg Res 2024; 19:143. [PMID: 38365801 PMCID: PMC10870541 DOI: 10.1186/s13018-024-04550-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 01/09/2024] [Indexed: 02/18/2024] Open
Abstract
BACKGROUND The capsule of the zygapophyseal joint plays an important role in motion segmental stability maintenance. Iatrogenic capsule injury is a common phenomenon in posterior approach lumbar interbody fusion operations, but whether this procedure will cause a higher risk of adjacent segment degeneration acceleration biomechanically has yet to be identified. METHODS Posterior lumbar interbody fusion (PLIF) with different grades of iatrogenic capsule injury was simulated in our calibrated and validated numerical model. By adjusting the cross-sectional area of the capsule, different grades of capsule injury were simulated. The stress distribution on the cranial motion segment was computed under different loading conditions to judge the potential risk of adjacent segment degeneration acceleration. RESULTS Compared to the PLIF model with an intact capsule, a stepwise increase in the stress value on the cranial motion segment can be observed with a step decrease in capsule cross-sectional areas. Moreover, compared to the difference between models with intact and slightly injured capsules, the difference in stress values was more evident between models with slight and severe iatrogenic capsule injury. CONCLUSION Intraoperative capsule protection can reduce the potential risk of adjacent segment degeneration acceleration biomechanically, and iatrogenic capsule damage on the cranial motion segment should be reduced to optimize patients' long-term prognosis.
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Affiliation(s)
- Fei Huang
- Department of Orthopedics, Meishan Hospital of Traditional Chinese Medicine, Meishan, China
| | - Gang Huang
- Luzhou Key Laboratory of Orthopedic Disorders, Southwest Medical University, No. 182, Chunhui Road, Luzhou, 646000, Sichuan Province, People's Republic of China
| | - Junpengli Jia
- Luzhou Key Laboratory of Orthopedic Disorders, Southwest Medical University, No. 182, Chunhui Road, Luzhou, 646000, Sichuan Province, People's Republic of China
| | - Shihao Lu
- Department of Orthopedics, Changzheng Hospital Affiliated to the Naval Medical University, Xiangyin Road, Shanghai, 200433, People's Republic of China.
| | - Jingchi Li
- Department of Orthopedics, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, No. 182, Chunhui Road, Longmatan District, Luzhou, 646000, Sichuan Province, People's Republic of China.
- Luzhou Key Laboratory of Orthopedic Disorders, Southwest Medical University, No. 182, Chunhui Road, Luzhou, 646000, Sichuan Province, People's Republic of China.
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Wu J, Miao J, Chen G, Xu H, Wen W, Xu H, Liu L. Finite element biomechanical analysis of 3D printed intervertebral fusion cage in osteoporotic population. BMC Musculoskelet Disord 2024; 25:129. [PMID: 38347518 PMCID: PMC10860281 DOI: 10.1186/s12891-024-07221-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 01/21/2024] [Indexed: 02/15/2024] Open
Abstract
OBJECTIVE To study the biomechanical characteristics of each tissue structure when using different 3D printing Cage in osteoporotic patients undergoing interbody fusion. METHODS A finite element model of the lumbar spine was reconstructed and validated with regarding a range of motion and intervertebral disc pressure from previous in vitro studies. Cage and pedicle screws were implanted and part of the lamina, spinous process, and facet joints were removed in the L4/5 segment of the validated mode to simulate interbody fusion. A 280 N follower load and 7.5 N·m moment were applied to different postoperative models and intact osteoporotic model to simulate lumbar motion. The biomechanical characteristics of different models were evaluated by calculating and analyzing the range of motion of the fixed and cephalic adjacent segment, the stress of the screw-rod system, the stress at the interface between cage and L5 endplate, and intervertebral disc pressure of the adjacent segment. RESULTS After rigid fixation, the range of motion of the fixed segment of model A-C decreased significantly, which was much smaller than that of the osteoporotic model. And with the increase of the axial area of the interbody fusion cages, the fixed segment of model A-C tended to be more stable. The range of motion and intradiscal pressure of the spinal models with different interbody fusion cages were higher than those of the complete osteoporosis model, but there was no significant difference between the postoperative models. On the other hand, the L5 upper endplate stress and screw-rod system stress of model A-C show a decreasing trend in different directions of motion. The stress of the endplate is the highest during flexion, which can reach 40.5 MPa (model A). The difference in endplate stress between models A-C was the largest during lateral bending. The endplate stress of models A and B was 150.5% and 140.9% of that of model C, respectively. The stress of the screw-rod system was the highest during lateral bending (model A, 102.0 MPa), which was 108.4%, 102.4%, 110.4%, 114.2% of model B and 158.5%, 110.1%, 115.8%, 125.4% of model C in flexion, extension, lateral bending, and rotation, respectively. CONCLUSIONS For people with osteoporosis, no matter what type of cage is used, good immediate stability can be achieved after surgery. Larger cage sizes provide better fixation without significantly increasing ROM and IDP in adjacent segments, which may contribute to the development of ASD. In addition, larger cage sizes can disperse endplate stress and reduce stress concentration, which is of positive significance in preventing cage subsidence after operation. The cage and screw rod system establish a stress conduction pathway on the spine, and a larger cage greatly enhances the stress-bearing capacity of the front column, which can better distribute the stress of the posterior spine structure and the stress borne by the posterior screw rod system, reduce the stress concentration phenomenon of the nail rod system, and avoid exceeding the yield strength of the material, resulting in the risk of future instrument failure.
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Affiliation(s)
- Jincheng Wu
- Department of Emergency Trauma Surgery, The Second Affiliated Hospital of Hainan Medical University, Haikou City, Hainan, China, 48 Baishuitang Road, Longhua District, 571700
| | - Jun Miao
- Tianjin Hospital, Tianjin University, Tianjin, China
| | | | - Hanpeng Xu
- Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Wangqiang Wen
- The First Affiliated Hospital of Hainan Medical University, Haikou City, Hainan, China
| | - Haoxiang Xu
- The Second People's Hospital of Hefei, Hefei, Anhui, China
| | - Lizhu Liu
- Department of Emergency Trauma Surgery, The Second Affiliated Hospital of Hainan Medical University, Haikou City, Hainan, China, 48 Baishuitang Road, Longhua District, 571700.
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Hambli R, De Leacy R, Cornelis F, Vienney C. Finite element investigation of the influence of a new transpedicular vertebral implant positioning on biomechanical responses of the spine segment. Med Eng Phys 2024; 124:104100. [PMID: 38418016 DOI: 10.1016/j.medengphy.2024.104100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 11/07/2023] [Accepted: 01/01/2024] [Indexed: 03/01/2024]
Abstract
The optimal positioning of an implant into a living organ such as femurs and vertebra is still an open problem. In particular, vertebral implant position has a significant impact on the results on spine behaviour after treatment in terms of stiffness, range of motion (ROM), wear, loosening and failure. In the current work, a 3D finite element analysis was conducted to investigate the positioning parameters of a novel transpedicular implant (V-STRUT©, Hyprevention, France) in terms of placement of the implant in the treated vertebra. The implant was designed in order to strength osteoporotic vertebral body and the related spine segment under compressive load. The effects of the axial and sagittal positions of the implant in the treated vertebra was investigated in terms of stress and stiffness variations. A 3D finite element model of an osteoporotic spine segment was built based on a Computed Tomography (CT) scan of an osteoporotic female (69 yo). The model is composed of T12, L1 and L2 vertebrae and corresponding intervertebral discs and ligaments. The bone tissue was modeled as a heterogeneous material with properties assigned based on the grey scale levels. The intervertebral discs were modeled using two regions describing the annulus and the nucleus and linear beam elements with specific stiffness each were used representing each ligament. The simulations indicated that the sagittal position (distance d) plays a role on the stress distribution. The closer the implant to the interior wall the lower the stress applied to the spine segment. Nevertheless, the axial plane position (distance h) have limited effects on the stress applied to the bone with a higher stress applied to the device (subjected to a higher bending load). These results can have direct clinical implications when dealing with the optimal placement of the implant. It is also possible to select a particular position in order to assign a given (target) stiffness for a patient.
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Affiliation(s)
- Ridha Hambli
- Univ. Orléans, Univ. Tours, INSA CVL, LaMé, 45000 Orléans, France.
| | - Reade De Leacy
- Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - François Cornelis
- Memorial Sloan Kettering Cancer Center & Weill Cornell Medical College, Radiology Department, 1275 York Avenue, New York, NY 10065, USA
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Wu Y, Ma J, Dai J, Wang Y, Bai H, Lu B, Chen J, Fan X, Ma X. Design and Biomechanical Evaluation of a Bidirectional Expandable Cage for Oblique Lateral Interbody Fusion. World Neurosurg 2023; 180:e644-e652. [PMID: 37805128 DOI: 10.1016/j.wneu.2023.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 10/01/2023] [Indexed: 10/09/2023]
Abstract
OBJECTIVE Oblique lateral interbody fusion (OLIF) surgery is a minimally invasive spinal surgery technique that has become increasingly popular in recent years. The primary objective of the current study was to design a minimally invasive expandable fusion device that can reduce iatrogenic nerve damage and minimize endplate damage during OLIF surgery, while restoring intervertebral height and alignment. The second objective was to use finite element analysis to evaluate the biomechanical stability of the newly designed expandable fusion device after implantation into the intervertebral space. METHODS A new bidirectional expandable cage was designed in this study. A finite element model (FEM) of L3-L5 lumbar segment was modified to simulate decompression and fusion. The modified FEMs were constructed in the following cases: intact model, bidirectional expandable cage (alone, with unilateral pedicle screws [UPSs], and with bilateral pedicle screws [BPSs]) model, conventional OLIF cage (alone, with UPSs, and with BPSs) model. To simulate physiological loadings, the models were subjected to a follower compressive pre-load of 400 N, in addition to 8.0 Nm of flexion, extension, lateral bending, and axial rotation moments. RESULT All modified FEMs exhibited a significant reduction in motion at L3-L5 compared to the intact model. Among the fusion models, the bidirectional expandable cage (BEC) with BPS model displayed the highest stiffness and demonstrated a reduced range of motion (48.5%-75.7%). Additionally, the peak stress on the endplate in the conventional OLIF cage (Conv-OLIF) model was generally lower than that in the BEC models. The cage in the BEC ALONE model exhibited the highest stress (93.87-176.3 MPa) on the endplate in most motion modes, while the cage in the Conv-OLIF+BPS model had the lowest stress (16.67-30.58 MPa) on the endplate in most motion modes. The maximum stress on the fixation in the BEC fusion models was generally lower than that in the Conv-OLIF fusion group under the same loading conditions. The OLIF ALONE model had the lowest stress on the adjacent disc, while the stress level in the BEC ALONE model was very close to it. CONCLUSIONS The BEC implanted models had higher stiffness, and more proper stress distribution on the posterior fixation was comparable to that of the Conv-OLIF models. However, the endplate stress peaks and cage stress peaks of the BEC models were slightly higher than those of the Conv-OLIF models, though still within a clinically acceptable range. Taking into account both biomechanical and clinical perspectives, BEC-assisted unilateral pedicle screw fixation meet clinical demand and may serve as a viable alternative to Conv-OLIF fusion.
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Affiliation(s)
- Yanfei Wu
- Clinical College of Orthopedics, Tianjin Medical University, Tianjin, People's Republic of China; Department of Spinal Surgery, Tianjin Hospital, Tianjin, People's Republic of China
| | - Jianxiong Ma
- Department of Spinal Surgery, Tianjin Hospital, Tianjin, People's Republic of China
| | - Jing Dai
- Clinical College of Orthopedics, Tianjin Medical University, Tianjin, People's Republic of China; Department of Spinal Surgery, Tianjin Hospital, Tianjin, People's Republic of China
| | - Ying Wang
- Department of Spinal Surgery, Tianjin Hospital, Tianjin, People's Republic of China
| | - Haohao Bai
- Department of Spinal Surgery, Tianjin Hospital, Tianjin, People's Republic of China
| | - Bin Lu
- Department of Spinal Surgery, Tianjin Hospital, Tianjin, People's Republic of China
| | - Jiahui Chen
- Clinical College of Orthopedics, Tianjin Medical University, Tianjin, People's Republic of China; Department of Spinal Surgery, Tianjin Hospital, Tianjin, People's Republic of China
| | - Xiancheng Fan
- Department of Spinal Surgery, Tianjin Hospital, Tianjin, People's Republic of China
| | - Xinlong Ma
- Clinical College of Orthopedics, Tianjin Medical University, Tianjin, People's Republic of China; Department of Spinal Surgery, Tianjin Hospital, Tianjin, People's Republic of China.
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Wang J, Geng Z, Ma X, Zhang Z, Miao J. A comparative analysis of using cage acrossing the vertebral ring apophysis in normal and osteoporotic models under endplate injury: a finite element analysis. Front Bioeng Biotechnol 2023; 11:1263751. [PMID: 38026854 PMCID: PMC10664026 DOI: 10.3389/fbioe.2023.1263751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 10/23/2023] [Indexed: 12/01/2023] Open
Abstract
Background: Lateral lumbar fusion is an advanced, minimally invasive treatment for degenerative lumbar diseases. It involves different cage designs, primarily varying in size. This study aims to investigate the biomechanics of the long cage spanning the ring apophysis in both normal and osteoporotic models, considering endplate damage, using finite element analysis. Methods: Model 1 was an intact endplate with a long cage spanning the ring apophysis. Model 2 was an endplate decortication with a long cage spanning the ring apophysis. Model 3 was an intact endplate with a short cage. Model 4 was an endplate decortication with a short cage. On the basis of the four original models, further osteoporosis models were created, yielding a total of eight finite element models. The provided passage delineates a study that elucidates the utilization of finite element analysis as a methodology to simulate and analyze the biomechanical repercussions ensuing from the adoption of two distinct types of intervertebral fusion devices (cages) within the physiological framework of a human body. Results: The investigation found no appreciable changes between Models 1 and 2 in the range of motion at the fixed and neighboring segments, the L3-4 IDP, screw-rod stress, endplate stress, or stress on the trabecular bone of the L5. Increases in these stresses were seen in models 3 and 4 in the ranges of 0.4%-676.1%, 252.9%-526.9%, 27.3%-516.6%, and 11.4%-109.3%, respectively. The osteoporotic models for scenarios 3 and 4 exhibit a similar trend to their respective normal bone density models, but these osteoporotic models consistently have higher numerical values. In particular, except for L3-4 IDP, the maximum values of these parameters in osteoporotic Models 3 and 4 were much higher than those in normal bone quality Models 1 and 2, rising by 385.3%, 116%, 435.1%, 758.3%, and 786.1%, respectively. Conclusion: Regardless of endplate injury or osteoporosis, it is advised to utilize a long cage that is 5 mm longer on each side than the bilateral pedicles because it has good biomechanical features and may lower the likelihood of problems after surgery. Additionally, using Long cages in individuals with osteoporosis may help avoid adjacent segment disease.
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Affiliation(s)
| | | | | | - Zepei Zhang
- Tianjin Hospital of Tianjin University, Tianjin, China
| | - Jun Miao
- Tianjin Hospital of Tianjin University, Tianjin, China
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Shang P, Ma B, Hou G, Zhang Y, Cui L, Song W, Liu Y. A novel artificial vertebral implant with Gyroid porous structures for reducing the subsidence and mechanical failure rate after vertebral body replacement. J Orthop Surg Res 2023; 18:828. [PMID: 37924130 PMCID: PMC10623881 DOI: 10.1186/s13018-023-04310-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2023] [Accepted: 10/22/2023] [Indexed: 11/06/2023] Open
Abstract
BACKGROUND Prosthesis subsidence and mechanical failure were considered significant threats after vertebral body replacement during the long-term follow-up. Therefore, improving and optimizing the structure of vertebral substitutes for exceptional performance has become a pivotal challenge in spinal reconstruction. METHODS The study aimed to develop a novel artificial vertebral implant (AVI) with triply periodic minimal surface Gyroid porous structures to enhance the safety and stability of prostheses. The biomechanical performance of AVIs under different loading conditions was analyzed using the finite element method. These implants were fabricated using selective laser melting technology and evaluated through static compression and subsidence experiments. RESULTS The results demonstrated that the peak stress in the Gyroid porous AVI was consistently lower than that in the traditional porous AVI under all loading conditions, with a maximum reduction of 73.4%. Additionally, it effectively reduced peak stress at the bone-implant interface of the vertebrae. Static compression experiments demonstrated that the Gyroid porous AVI was about 1.63 times to traditional porous AVI in terms of the maximum compression load, indicating that Gyroid porous AVI could meet the safety requirement. Furthermore, static subsidence experiments revealed that the subsidence tendency of Gyroid porous AVI in polyurethane foam (simulated cancellous bone) was approximately 15.7% lower than that of traditional porous AVI. CONCLUSIONS The Gyroid porous AVI exhibited higher compressive strength and lower subsidence tendency than the strut-based traditional porous AVI, indicating it may be a promising substitute for spinal reconstruction.
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Affiliation(s)
- Peng Shang
- School of Mechanical Engineering, Hebei University of Technology, Tianjin, China.
| | - Benyuan Ma
- School of Mechanical Engineering, Hebei University of Technology, Tianjin, China
| | - Guanghui Hou
- School of Mechanical Engineering, Hebei University of Technology, Tianjin, China
| | - Yihai Zhang
- School of Mechanical Engineering, Hebei University of Technology, Tianjin, China
| | - Lunxu Cui
- School of Mechanical Engineering, Hebei University of Technology, Tianjin, China
| | - Wanzhen Song
- School of Mechanical Engineering, Hebei University of Technology, Tianjin, China
| | - Yancheng Liu
- Department of Bone and Soft Tissue Oncology, Tianjin Hospital, Tianjin, China.
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Pokorni AJ, Turbucz M, Kiss RM, Eltes PE, Lazary A. Comparison of anterior column reconstruction techniques after en bloc spondylectomy: a finite element study. Sci Rep 2023; 13:18767. [PMID: 37907570 PMCID: PMC10618450 DOI: 10.1038/s41598-023-45736-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Accepted: 10/23/2023] [Indexed: 11/02/2023] Open
Abstract
Total en bloc spondylectomy (TES) effectively treats spinal tumors. The surgery requires a vertebral body replacement (VBR), for which several solutions were developed, whereas the biomechanical differences between these devices still need to be completely understood. This study aimed to compare a femur graft, a polyetheretherketone implant (PEEK-IMP-C), a titan mesh cage (MESH-C), and a polymethylmethacrylate replacement (PMMA-C) using a finite element model of the lumbar spine after a TES of L3. Several biomechanical parameters (rotational stiffness, segmental range of motion (ROM), and von Mises stress) were assessed to compare the VBRs. All models provided adequate initial stability by increasing the rotational stiffness and decreasing the ROM between L2 and L4. The PMMA-C had the highest stiffness for flexion-extension, lateral bending, and axial rotation (215%, 216%, and 170% of intact model), and it had the lowest segmental ROM in the instrumented segment (0.2°, 0.5°, and 0.7°, respectively). Maximum endplate stress was similar for PMMA-C and PEEK-IMP-C but lower for both compared to MESH-C across all loading directions. These results suggest that PMMA-C had similar or better primary spinal stability than other VBRs, which may be related to the larger contact surface and the potential to adapt to the patient's anatomy.
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Affiliation(s)
- Agoston Jakab Pokorni
- In Silico Biomechanics Laboratory, National Center for Spinal Disorders, Királyhágó St. 1-3, Budapest, 1126, Hungary
- School of PhD Studies, Semmelweis University, Budapest, Hungary
| | - Mate Turbucz
- In Silico Biomechanics Laboratory, National Center for Spinal Disorders, Királyhágó St. 1-3, Budapest, 1126, Hungary
- School of PhD Studies, Semmelweis University, Budapest, Hungary
| | - Rita Maria Kiss
- Department of Mechatronics, Optics and Mechanical Engineering Informatics, Faculty of Mechanical Engineering, Budapest University of Technology and Economics, Műegyetem Rkp. 3., Budapest, 1111, Hungary
| | - Peter Endre Eltes
- In Silico Biomechanics Laboratory, National Center for Spinal Disorders, Királyhágó St. 1-3, Budapest, 1126, Hungary.
- Department of Spine Surgery, Department of Orthopaedics, Semmelweis University, Budapest, Hungary.
| | - Aron Lazary
- In Silico Biomechanics Laboratory, National Center for Spinal Disorders, Királyhágó St. 1-3, Budapest, 1126, Hungary
- Department of Spine Surgery, Department of Orthopaedics, Semmelweis University, Budapest, Hungary
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Hou Z, Wang W, Su S, Chen Y, Chen L, Lu Y, Zhou H. Bibliometric and Visualization Analysis of Biomechanical Research on Lumbar Intervertebral Disc. J Pain Res 2023; 16:3441-3462. [PMID: 37869478 PMCID: PMC10590139 DOI: 10.2147/jpr.s428991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 09/28/2023] [Indexed: 10/24/2023] Open
Abstract
Background Biomechanical research on the lumbar intervertebral disc (IVD) provides valuable information for the diagnosis, treatment, and prevention of related diseases, and has received increasing attention. Using bibliometric methods and visualization techniques, this study investigates for the first time the research status and development trends in this field, with the aim of providing guidance and support for subsequent research. Methods The Science Citation Index Expanded (SCI-Expanded) within the Web of Science Core Collection (WoSCC) database was used as the data source to select literature published from 2003 to 2022 related to biomechanical research on lumbar IVD. VOSviewer 1.6.19 and CiteSpace 6.2.R2 visualization software, as well as the online analysis platform of literature metrology, were utilized to generate scientific knowledge maps for visual display and data analysis. Results The United States is the most productive country in this field, with the Ulm University making the largest contribution. Wilke HJ is both the most prolific author and one of the highly cited authors, while Adams MA is the most cited author. Spine, J Biomech, Eur Spine J, Spine J, and Clin Biomech are not only the journals with the highest number of publications, but also highly cited journals. The main research topics in this field include constructing and validating three-dimensional (3D) finite element model (FEM) of lumbar spine, measuring intradiscal pressure, exploring the biomechanical effects and related risk factors of lumbar disc degeneration, studying the mechanical responses to different torque load combinations, and classifying lumbar disc degeneration based on magnetic resonance images (MRI), which are also the hot research themes in recent years. Conclusion This study systematically reviews the knowledge system and development trends in the field of biomechanics of lumbar IVD, providing valuable references for further research.
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Affiliation(s)
- Zhaomeng Hou
- Faculty of Orthopedics and Traumatology, Guangxi University of Chinese Medicine, Nanning, People’s Republic of China
- Department of Orthopedics and Traumatology, Yancheng TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Yancheng, People’s Republic of China
- Department of Orthopedics and Traumatology, Yancheng TCM Hospital, Yancheng, People’s Republic of China
| | - Wei Wang
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Guangxi University of Chinese Medicine, Nanning, People’s Republic of China
| | - Shaoting Su
- Faculty of Orthopedics and Traumatology, Guangxi University of Chinese Medicine, Nanning, People’s Republic of China
| | - Yixin Chen
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Guangxi University of Chinese Medicine, Nanning, People’s Republic of China
| | - Longhao Chen
- Faculty of Orthopedics and Traumatology, Guangxi University of Chinese Medicine, Nanning, People’s Republic of China
- Guangxi Key Laboratory of Biomechanics and Injury Repair in Traditional Chinese Medicine Orthopedics and Traumatology, Nanning, People’s Republic of China
| | - Yan Lu
- Faculty of Orthopedics and Traumatology, Guangxi University of Chinese Medicine, Nanning, People’s Republic of China
- Guangxi Key Laboratory of Biomechanics and Injury Repair in Traditional Chinese Medicine Orthopedics and Traumatology, Nanning, People’s Republic of China
- Department of Orthopedics and Traumatology, The First Affiliated Hospital of Guangxi University of Chinese Medicine, Nanning, People’s Republic of China
| | - Honghai Zhou
- Faculty of Orthopedics and Traumatology, Guangxi University of Chinese Medicine, Nanning, People’s Republic of China
- Guangxi Key Laboratory of Biomechanics and Injury Repair in Traditional Chinese Medicine Orthopedics and Traumatology, Nanning, People’s Republic of China
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Xu C, Xi Z, Fang Z, Zhang X, Wang N, Li J, Liu Y. Annulus Calibration Increases the Computational Accuracy of the Lumbar Finite Element Model. Global Spine J 2023; 13:2310-2318. [PMID: 35293827 PMCID: PMC10538312 DOI: 10.1177/21925682221081224] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
STUDY DESIGN Mechanical simulations. OBJECTIVE Inadequate calibration of annuli negatively affects the computational accuracy of finite element (FE) models. Specifically, the definition of annulus average radius (AR) does not have uniformity standards. Differences between the elastic moduli in the different layers and parts of the annulus were not fully calibrated when a linear elastic material is used to define its material properties. This study aims to optimize the computational accuracy of the FE model by calibrating the annulus. METHODS We calibrated the annulus AR and elastic modulus in our anterior-constructed lumbar model by eliminating the difference between the computed range of motion and that measured by in vitro studies under a flexion-extension loading condition. Multi-indicator validation was performed by comparing the computed indicators with those measured in in vitro studies. The computation time required for the different models has also been recorded to evaluate the computational efficiency. RESULTS The difference between computed and measured ROMs was less than 1% when the annulus AR and elastic modulus were calibrated. In the model validation process, all the indicators computed by the calibrated FE model were within ±1 standard deviation of the average values obtained from in vitro studies. The maximum difference between the computed and measured values was less than 10% under nearly all loading conditions. There is no apparent variation tendency for the computational time associated with different models. CONCLUSION The FE model with calibrated annulus AR and regional elastic modulus has higher computational accuracy and can be used in subsequent mechanical studies.
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Affiliation(s)
- Chen Xu
- Department of Spine Surgery, Shanghai Changzheng Hospital, Naval Medical University, Shanghai, China
| | - Zhipeng Xi
- Department of Orthopedics, Jiangsu Province Hospital on Integration of Chinese and Western Medicine, Nanjing, China
| | - Zhongxin Fang
- Fluid and Power Machinery Key Laboratory of Ministry of Education, Xihua University, Chengdu, China
| | - Xiaoyu Zhang
- Department of Orthopedics, Jiangsu Province Hospital on Integration of Chinese and Western Medicine, Nanjing, China
| | - Nan Wang
- Department of Orthopedics, Jiangsu Province Hospital on Integration of Chinese and Western Medicine, Nanjing, China
| | - Jingchi Li
- Department of Spine Surgery, Shanghai Changzheng Hospital, Naval Medical University, Shanghai, China
- Department of Orthopedics, Hospital (T.C.M) Affiliated to Southwest Medical University, Luzhou, China
| | - Yang Liu
- Department of Spine Surgery, Shanghai Changzheng Hospital, Naval Medical University, Shanghai, China
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Polanco M, Ringleb S, Audette M, Kakar R, Bawab S. A comparison of intervertebral ligament properties utilized in a thoracic spine functional unit through kinematic evaluation. Comput Methods Biomech Biomed Engin 2023; 26:1330-1340. [PMID: 36106656 DOI: 10.1080/10255842.2022.2115293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 07/25/2022] [Accepted: 08/16/2022] [Indexed: 11/03/2022]
Abstract
Ligament properties in the literature are variable, yet scarce, but needed to calibrate computational models for spine clinical research applications. A comparison of ligament stiffness properties and their effect on the kinematic behavior of a thoracic functional spinal unit (FSU) is examined in this paper. Six unique ligament property sets were utilized within a volumetric T7-T8 finite element (FE) model developed using computer-aided design (CAD) spinal geometry. A 7.5 Nm moment was applied along three anatomical planes both with and without costovertebral (CV) joints present. Range of Motion (RoM) was assessed for each property set and compared to published experimental data. Intact and serial ligament removal procedures were implemented in accordance with experimental protocol. The variance in both kinematic behavior and comparability with experimental data among property sets emphasizes the role nonlinear characterization plays in determining proper kinematic behavior in spinal FE models. Additionally, a decrease in RoM variation among property sets was exhibited when the model setup incorporated the CV joint. With proper assessment of the source and size of each ligament, the material properties considered here could be expanded and justified for implementation into thoracic spine clinical studies.
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Affiliation(s)
- Michael Polanco
- Mechanical and Aerospace Engineering Department, Old Dominion University, Norfolk, VA, USA
| | - Stacie Ringleb
- Mechanical and Aerospace Engineering Department, Old Dominion University, Norfolk, VA, USA
| | - Michel Audette
- Computational Modeling and Simulation Engineering, Old Dominion University, Norfolk, VA, USA
| | - Rumit Kakar
- School of Health Sciences, Oakland University, Rochester, MI, USA
| | - Sebastian Bawab
- Mechanical and Aerospace Engineering Department, Old Dominion University, Norfolk, VA, USA
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Wang J, Geng Z, Wu J, Liu J, Zhang Z, Miao J, Li R. Biomechanical properties of lumbar vertebral ring apophysis cage under endplate injury: a finite element analysis. BMC Musculoskelet Disord 2023; 24:695. [PMID: 37649054 PMCID: PMC10466841 DOI: 10.1186/s12891-023-06792-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 08/10/2023] [Indexed: 09/01/2023] Open
Abstract
OBJECTIVE This study aimed to compare the biomechanical properties of lumbar interbody fusion involving two types of cages. The study evaluated the effectiveness of the cage spanning the ring apophysis, regardless of the endplate's integrity. METHODS A finite element model of the normal spine was established and validated in this study. The validated model was then utilized to simulate Lateral Lumbar Interbody Fusion (LLIF) with posterior pedicle screw fixation without posterior osteotomy. Two models of interbody fusion cage were placed at the L4/5 level, and the destruction of the bony endplate caused by curetting the cartilaginous endplate during surgery was simulated. Four models were established, including Model 1 with an intact endplate and long cage spanning the ring apophysis, Model 2 with endplate decortication and long cage spanning the ring apophysis, Model 3 with an intact endplate and short cage, and Model 4 with endplate decortication and short cage. Analyzed were the ROM of the fixed and adjacent segments, screw rod system stress, interface stress between cage and L5 endplate, trabecular bone stress on the upper surface of L5, and intervertebral disc pressure (IDP) of adjacent segments. RESULTS There were no significant differences in ROM and IDP between adjacent segments in each postoperative model. In the short cage model, the range of motion (ROM), contact pressure between the cage and endplate, stress in L5 cancellous bone, and stress in the screw-rod system all exhibited an increase ranging from 0.4% to 79.9%, 252.9% to 526.9%, 27.3% to 133.3%, and 11.4% to 107%, respectively. This trend was further amplified when the endplate was damaged, resulting in a maximum increase of 88.6%, 676.1%, 516.6%, and 109.3%, respectively. Regardless of the integrity of the endplate, the long cage provided greater support strength compared to the short cage. CONCLUSIONS Caution should be exercised during endplate preparation and cage placement to maintain the endplate's integrity. Based on preoperative X-ray evaluation, the selection of a cage that exceeds the width of the pedicle by at least 5 mm (ensuring complete coverage of the vertebral ring) has demonstrated remarkable biomechanical performance in lateral lumbar interbody fusion procedures. By opting for such a cage, we expect a reduced occurrence of complications, including cage subsidence, internal fixation system failure, and rod fracture.
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Affiliation(s)
- Jian Wang
- Department of Spine Surgery, Tianjin Hospital, Tianjin University, No. 406 Jiefang South Rd, Hexi District, Tianjin, 300211, China
| | - Ziming Geng
- Department of Spine Surgery, Tianjin Hospital, Tianjin University, No. 406 Jiefang South Rd, Hexi District, Tianjin, 300211, China
| | - Jincheng Wu
- The Second Affiliated Hospital of Hainan Medical University, Haikou City, Hainan, China
| | - Jianchao Liu
- Department of Spine Surgery, Tianjin Hospital, Tianjin University, No. 406 Jiefang South Rd, Hexi District, Tianjin, 300211, China
| | - Zepei Zhang
- Department of Spine Surgery, Tianjin Hospital, Tianjin University, No. 406 Jiefang South Rd, Hexi District, Tianjin, 300211, China
| | - Jun Miao
- Department of Spine Surgery, Tianjin Hospital, Tianjin University, No. 406 Jiefang South Rd, Hexi District, Tianjin, 300211, China.
| | - Ruihua Li
- Department of Spine Surgery, Tianjin Hospital, Tianjin University, No. 406 Jiefang South Rd, Hexi District, Tianjin, 300211, China.
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Cheng CH, Chiu PY, Chen HB, Niu CC, Nikkhoo M. The influence of over-distraction on biomechanical response of cervical spine post anterior interbody fusion: a comprehensive finite element study. Front Bioeng Biotechnol 2023; 11:1217274. [PMID: 37650042 PMCID: PMC10464836 DOI: 10.3389/fbioe.2023.1217274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 08/04/2023] [Indexed: 09/01/2023] Open
Abstract
Introduction: Anterior cervical discectomy and fusion (ACDF) has been considered as the gold standard surgical treatment for cervical degenerative pathologies. Some surgeons tend to use larger-sized interbody cages during ACDF to restore the index intervertebral disc height, hence, this study evaluated the effect of larger-sized interbody cages on the cervical spine with ACDF under both static and cyclic loading. Method: Twenty pre-operative personalized poro-hyperelastic finite element (FE) models were developed. ACDF post-operative models were then constructed and four clinical scenarios (i.e., 1) No-distraction; 2) 1 mm distraction; 3) 2 mm distraction; and 4) 3 mm distraction) were predicted for each patient. The biomechanical responses at adjacent spinal levels were studied subject to static and cyclic loading. Non-parametric Friedman statistical comparative tests were performed and the p values less than 0.05 were reflected as significant. Results: The calculated intersegmental range of motion (ROM) and intradiscal pressure (IDP) from 20 pre-operative FE models were within the overall ranges compared to the available data from literature. Under static loading, greater ROM, IDP, facet joint force (FJF) values were detected post ACDF, as compared with pre-op. Over-distraction induced significantly higher IDP and FJF in both upper and lower adjacent levels in extension. Higher annulus fibrosus stress and strain values, and increased disc height and fluid loss at the adjacent levels were observed in ACDF group which significantly increased for over-distraction groups. Discussion: it was concluded that using larger-sized interbody cages (the height of ≥2 mm of the index disc height) can result in remarkable variations in biomechanical responses of adjacent levels, which may indicate as risk factor for adjacent segment disease. The results of this comprehensive FE investigation using personalized modeling technique highlight the importance of selecting the appropriate height of interbody cage in ACDF surgery.
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Affiliation(s)
- Chih-Hsiu Cheng
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Bone and Joint Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Ping-Yeh Chiu
- Bone and Joint Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan
- Department of Orthopedic Surgery, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Hung-Bin Chen
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chi-Chien Niu
- Bone and Joint Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan
- Department of Orthopedic Surgery, Chang Gung Memorial Hospital, Linkou, Taiwan
| | - Mohammad Nikkhoo
- School of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Bone and Joint Research Center, Chang Gung Memorial Hospital, Linkou, Taiwan
- Department of Biomedical Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran
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Liu J, Gong X, Wang K, Li X, Zhang X, Sun J, Zhu Y, Ai Y, Ren J, Xiu J, Ji W. A comparison of the biomechanical properties of three different lumbar internal fixation methods in the treatment of lumbosacral spinal tuberculosis: finite element analysis. Sci Rep 2023; 13:11354. [PMID: 37443369 PMCID: PMC10344955 DOI: 10.1038/s41598-023-32624-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 03/30/2023] [Indexed: 07/15/2023] Open
Abstract
There are various internal fixation methods in treating lumbosacral spinal tuberculosis. The study compared the stability and stress distribution in surrounding tissues/implants, such as discs, endplates and screw-rod internal fixation system, etc. when applying three different lumbar internal fixation methods to treat lumbosacral spinal tuberculosis. A finite element model was constructed and validated. The spinal stability was restored using three methods: a titanium cage with lateral double screw-rod fixation (group 1), autologous bone with posterior double screw-rod fixation (group 2), and a titanium cage with posterior double screw-rod fixation (group 3). For comparison, group 4 represented the intact L3-S1 spine. Finally, a load was applied, and the ranges of motion and Von Mises stresses in the cortical endplates, screw-rod internal fixation system and cortical bone around the screws in the different groups were recorded and analyzed. All six ranges of motion (flexion, extension, left/right lateral bending, left/right rotation) of the surgical segment were substantially lower in groups 1 (0.53° ~ 1.41°), 2 (0.68° ~ 1.54°) and 3 (0.55° ~ 0.64°) than in group 4 (4.48° ~ 10.12°). The maximum stress in the screw-rod internal fixation system was clearly higher in group 2 than in groups 1 and 3 under flexion, left/right lateral bending, and left/right rotation. However, in extension, group 1 had the highest maximum stress in the screw-rod internal fixation system. Group 2 had the lowest peak stresses in the cortical endplates in all directions. The peak stresses in the cortical bone around the screws were higher in group 1 and group 2 than in group 3 in all directions. Thus, titanium cage with posterior double screw-rod fixation has more advantages in immediate reconstruction of lumbosacral spinal stability and prevention of screw loosening.
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Affiliation(s)
- Jiantao Liu
- Department of Orthopedics, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China.
| | - Xi Gong
- Xi'an Jiaotong University, Xi'an, 710049, China
| | - Kao Wang
- Medical School of Yan'an University, Yan'an, 716000, China
| | - Xingyuan Li
- Xi'an Jiaotong University, Xi'an, 710049, China
| | - Xiwei Zhang
- Xi'an Jiaotong University, Xi'an, 710049, China
| | - Jiajun Sun
- Xi'an Jiaotong University, Xi'an, 710049, China
| | - Yihan Zhu
- Xi'an Jiaotong University, Xi'an, 710049, China
| | - Yixiang Ai
- Xi'an Jiaotong University, Xi'an, 710049, China
| | - Jing Ren
- Department of Orthopedics, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Jintao Xiu
- Department of Orthopedics, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
| | - Wenchen Ji
- Department of Orthopedics, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, 710061, China
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Zhong Y, Wang Y, Zhou H, Wang Y, Gan Z, Qu Y, Hua R, Chen Z, Chu G, Liu Y, Jiang W. Biomechanical study of two-level oblique lumbar interbody fusion with different types of lateral instrumentation: a finite element analysis. Front Med (Lausanne) 2023; 10:1183683. [PMID: 37457575 PMCID: PMC10345158 DOI: 10.3389/fmed.2023.1183683] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 06/09/2023] [Indexed: 07/18/2023] Open
Abstract
Objective The aim of this study was to verify the biomechanical properties of a newly designed angulated lateral plate (mini-LP) suited for two-level oblique lumbar interbody fusion (OLIF). The mini-LP is placed through the lateral ante-psoas surgical corridor, which reduces the operative time and complications associated with prolonged anesthesia and placement in the prone position. Methods A three-dimensional nonlinear finite element (FE) model of an intact L1-L5 lumbar spine was constructed and validated. The intact model was modified to generate a two-level OLIF surgery model augmented with three types of lateral fixation (stand-alone, SA; lateral rod screw, LRS; miniature lateral plate, mini-LP); the operative segments were L2-L3 and L3-L4. By applying a 500 N follower load and 7.5 Nm directional moment (flexion-extension, lateral bending, and axial rotation), all models were used to simulate human spine movement. Then, we extracted the range of motion (ROM), peak contact force of the bony endplate (PCFBE), peak equivalent stress of the cage (PESC), peak equivalent stress of fixation (PESF), and stress contour plots. Results When compared with the intact model, the SA model achieved the least reduction in ROM to surgical segments in all motions. The ROM of the mini-LP model was slightly smaller than that of the LRS model. There were no significant differences in surgical segments (L1-L2, L4-L5) between all surgical models and the intact model. The PCFBE and PESC of the LRS and the mini-LP fixation models were lower than those of the SA model. However, the differences in PCFBE or PESC between the LRS- and mini-LP-based models were not significant. The fixation stress of the LRS- and mini-LP-based models was significantly lower than the yield strength under all loading conditions. In addition, the variances in the PESF in the LRS- and mini-LP-based models were not obvious. Conclusion Our biomechanical FE analysis indicated that LRS or mini-LP fixation can both provide adequate biomechanical stability for two-level OLIF through a single incision. The newly designed mini-LP model seemed to be superior in installation convenience, and equally good outcomes were achieved with both LRS and mini-LP for two-level OLIF.
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Affiliation(s)
- Yuan Zhong
- Department of Orthopaedic Surgery, Dushu Lake Hospital Affiliated to Soochow University, Suzhou, Jiangsu Province, China
| | - Yujie Wang
- Department of Orthopaedic Surgery, Dushu Lake Hospital Affiliated to Soochow University, Suzhou, Jiangsu Province, China
- Department of Orthopaedic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
| | - Hong Zhou
- Department of Orthopedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China
| | - Yudong Wang
- Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
| | - Ziying Gan
- Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
| | - Yimeng Qu
- Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
| | - Runjia Hua
- Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
| | - Zhaowei Chen
- Department of Orthopaedic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
- Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
| | - Genglei Chu
- Department of Orthopaedic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
- Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
| | - Yijie Liu
- Department of Orthopaedic Surgery, The First Affiliated Hospital of Soochow University, Suzhou, Jiangsu Province, China
- Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
| | - Weimin Jiang
- Department of Orthopaedic Surgery, Dushu Lake Hospital Affiliated to Soochow University, Suzhou, Jiangsu Province, China
- Suzhou Medical College, Soochow University, Suzhou, Jiangsu Province, China
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Yang H, Pan A, Hai Y, Cheng F, Ding H, Liu Y. Biomechanical evaluation of multiple pelvic screws and multirod construct for the augmentation of lumbosacral junction in long spinal fusion surgery. Front Bioeng Biotechnol 2023; 11:1148342. [PMID: 36998811 PMCID: PMC10043192 DOI: 10.3389/fbioe.2023.1148342] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 03/06/2023] [Indexed: 03/15/2023] Open
Abstract
Background: Posterior long spinal fusion was the common procedure for adult spinal deformity (ASD). Although the application of sacropelvic fixation (SPF), the incidence of pseudoarthrosis and implant failure is still high in long spinal fusion extending to lumbosacral junction (LSJ). To address these mechanical complications, advanced SPF technique by multiple pelvic screws or multirod construct has been recommended. This was the first study to compare the biomechanical performance of combining multiple pelvic screws and multirod construct to other advanced SPF constructs for the augmentation of LSJ in long spinal fusion surgery through finite element (FE) analysis.Methods: An intact lumbopelvic FE model based on computed tomography images of a healthy adult male volunteer was constructed and validated. The intact model was modified to develop five instrumented models, all of which had bilateral pedicle screw (PS) fixation from L1 to S1 with posterior lumbar interbody fusion and different SPF constructs, including No-SPF, bilateral single S2-alar-iliac (S2AI) screw and single rod (SS-SR), bilateral multiple S2AI screws and single rod (MS-SR), bilateral single S2AI screw and multiple rods (SS-MR), and bilateral multiple S2AI screws and multiple rods (MS-MR). The range of motion (ROM) and stress on instrumentation, cages, sacrum, and S1 superior endplate (SEP) in flexion (FL), extension (EX), lateral bending (LB), and axial rotation (AR) were compared among models.Results: Compared with intact model and No-SPF, the ROM of global lumbopelvis, LSJ, and sacroiliac joint (SIJ) was decreased in SS-SR, MS-SR, SS-MR, and MS-MR in all directions. Compared with SS-SR, the ROM of global lumbopelvis and LSJ of MS-SR, SS-MR, and MS-MR further decreased, while the ROM of SIJ was only decreased in MS-SR and MS-MR. The stress on instrumentation, cages, S1-SEP, and sacrum decreased in SS-SR, compared with no-SPF. Compared with SS-SR, the stress in EX and AR further decreased in SS-MR and MS-SR. The most significantly decreased ROM and stress were observed in MS-MR.Conclusion: Both multiple pelvic screws and multirod construct could increase the mechanical stability of LSJ and reduce stress on instrumentation, cages, S1-SEP, and sacrum. The MS-MR construct was the most adequate to reduce the risk of lumbosacral pseudarthrosis, implant failure, and sacrum fracture. This study may provide surgeons with important evidence for the application of MS-MR construct in the clinical settings.
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Affiliation(s)
| | | | - Yong Hai
- *Correspondence: Yong Hai, ; Yuzeng Liu,
| | | | | | - Yuzeng Liu
- *Correspondence: Yong Hai, ; Yuzeng Liu,
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Biomechanical and clinical studies on lumbar spine fusion surgery: a review. Med Biol Eng Comput 2023; 61:617-634. [PMID: 36598676 DOI: 10.1007/s11517-022-02750-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 12/22/2022] [Indexed: 01/05/2023]
Abstract
Low back pain is associated with degenerative disc diseases of the spine. Surgical treatment includes fusion and non-fusion types. The gold standard is fusion surgery, wherein the affected vertebral segment is fused. The common complication of fusion surgery is adjacent segment degeneration (ASD). The ASD often leads to revision surgery, calling for a further fusion of adjacent segments. The existing designs of nonfusion type implants are associated with clinical problems such as subsidence, difficulty in implantation, and the requirement of revision surgeries. Various surgical approaches have been adopted by the surgeons to insert the spinal implants into the affected segment. Over the years, extensive biomechanical investigations have been reported on various surgical approaches and prostheses to predict the outcomes of lumbar spine implantations. Computer models have been proven to be very effective in identifying the best prosthesis and surgical procedure. The objective of the study was to review the literature on biomechanical studies for the treatment of lumbar spinal degenerative diseases. A critical review of the clinical and biomechanical studies on fusion spine surgeries was undertaken. The important modeling parameters, challenges, and limitations of the current studies were identified, showing the future research directions.
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Recent Advances in Coupled MBS and FEM Models of the Spine—A Review. Bioengineering (Basel) 2023; 10:bioengineering10030315. [PMID: 36978705 PMCID: PMC10045105 DOI: 10.3390/bioengineering10030315] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/13/2023] [Accepted: 02/22/2023] [Indexed: 03/06/2023] Open
Abstract
How back pain is related to intervertebral disc degeneration, spinal loading or sports-related overuse remains an unanswered question of biomechanics. Coupled MBS and FEM simulations can provide a holistic view of the spine by considering both the overall kinematics and kinetics of the spine and the inner stress distribution of flexible components. We reviewed studies that included MBS and FEM co-simulations of the spine. Thereby, we classified the studies into unidirectional and bidirectional co-simulation, according to their data exchange methods. Several studies have demonstrated that using unidirectional co-simulation models provides useful insights into spinal biomechanics, although synchronizing the two distinct models remains a key challenge, often requiring extensive manual intervention. The use of a bidirectional co-simulation features an iterative, automated process with a constant data exchange between integrated subsystems. It reduces manual corrections of vertebra positions or reaction forces and enables detailed modeling of dynamic load cases. Bidirectional co-simulations are thus a promising new research approach for improved spine modeling, as a main challenge in spinal biomechanics is the nonlinear deformation of the intervertebral discs. Future studies will likely include the automated implementation of patient-specific bidirectional co-simulation models using hyper- or poroelastic intervertebral disc FEM models and muscle forces examined by an optimization algorithm in MBS. Applications range from clinical diagnosis to biomechanical analysis of overload situations in sports and injury prediction.
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Zhang XY, Han Y. Comparison of the biomechanical effects of lumbar disc degeneration on normal patients and osteoporotic patients: A finite element analysis. Med Eng Phys 2023; 112:103952. [PMID: 36842775 DOI: 10.1016/j.medengphy.2023.103952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 12/17/2022] [Accepted: 01/07/2023] [Indexed: 01/10/2023]
Abstract
BACKGROUND Some older patients who suffered from both conditions (disc degeneration and osteoporosis) have higher surgical risks and longer postoperative recovery times. Understanding the relation between disc degeneration and osteoporosis is fundamental to know the mechanisms of orthopedic disorders and improve clinical treatment. However, there is a lack of finite element (FE) studies to predict the combined effects of disc degeneration and osteoporosis. So the aim of the present study is to explore the differences of biomechanical effects of lumbar disc degeneration on normal patients and osteoporotic patients. METHODS A normal lumbar spine finite element model (FEM) was developed based on the geometric information of a healthy male subject (age 35 years; height 178 cm; weight 65 kg). This normal lumbar spine FEM was modified to build three lumbar spine degeneration models simulating mild, moderate and severe grades of disc degeneration at the L4-L5 segment. Then the degenerative lumbar spine models for osteoporotic patients were constructed on the basis of the above-mentioned degeneration models. Firstly, the normal model (flexion: 8 Nm; extension: 6 Nm; lateral bending: 6 Nm; torsion: 4 Nm) and degenerative models (10 Nm) were calibrated under pure moment load, respectively. Secondly, under a 400 N follower load, the 7.5 Nm moments of different directions were applied on all models to simulate different motion postures. Finally, under the above loading conditions, we calculated and analyzed the range of motion (ROM), Mises stress in cortical (MSC1), Mises stress in endplate (MSE), Mises stress in cancellous (MSC2), and Mises stress in post (MSP). RESULTS Compared with disc degeneration patients without osteoporosis, the ROM, MSC1, and MSE of osteoporosis patients with various disc degeneration decreased in all postures, while the MSC2 and MSP increased. With increase in the degree of disc degeneration, the reduction proportions of ROM and MSE in osteoporotic patients gradually increased, while the reduction percentages in MSC1 of osteoporotic patients gradually decreased. The increase percentages of MSC2 in osteoporotic patients gradually increased. Given the progressive changes of disc degeneration, the changes in MSP in osteoporosis patients were uneven. CONCLUSION In summary, the effect of disc degeneration on flexibility in the two kinds of patients (osteoporosis and non-osteoporosis patients) was nearly same. By comparing the remaining biomechanical parameters (MSC1, MSE, MSC2, and MSP), we found that degenerated intervertebral discs caused changes in loading patterns of osteoporosis patients. Disc degeneration reduced the Mises stress in the cortical and endplate, which increased the Mises stress in the cancellous and post. That is to say, in order to cope with the changes in bone stresses caused by disc degeneration and osteoporosis, clinicians should be more careful in choosing the surgical option for osteoporotic patients with disc degeneration.
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Affiliation(s)
- Xin-Ying Zhang
- Department of Infection Control, The Affiliated Hospital of Hebei University, Hebei, 071000, China
| | - Ye Han
- Department of Orthopaedics, The Affiliated Hospital of Hebei University, Hebei, 071000, China.
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Hambli R, De Leacy R, Vienney C. Effect of a new transpedicular vertebral device for the treatment or prevention of vertebral compression fractures: A finite element study. Clin Biomech (Bristol, Avon) 2023; 102:105893. [PMID: 36682151 DOI: 10.1016/j.clinbiomech.2023.105893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 01/08/2023] [Accepted: 01/10/2023] [Indexed: 01/15/2023]
Abstract
BACKGROUND A finite element study was performed to investigate the biomechanical performance of a novel transpedicular implant (V-STRUT©, Hyprevention, France) made of PEEK (polyetheretherketone) material in terms of strengthening the osteoporotic vertebra and the thoraco-lumbar spine. The objective was to assess numerically the efficacy of the implant to reduce the stress distribution within bone and absorb part of the stress by the implant thanks to its optimized material selection close to that of normal bone. METHODS A numerical model was generated based on a scan of an osteoporotic patient. The model is composed of three consecutive vertebrae and intervertebral discs. A heterogeneous distribution of bone material properties was assigned to the bone. In order to investigate the rationale of the device material selection, three FE models were developed (i) without the device to serve a reference model, (ii) with device made in Titanium material and (iii) with device made in PEEK material. Stiffness and stress distribution within the spine segment were computed and compared in order to assess the implants' performances. FINDINGS The results obtained by the simulations indicated that the novel transpedicular implant made of PEEK material provided support to the superior vertebral endplate, restored the thoraco-lumbar spine segment stiffness and reduced the stress applied to the vertebrae under the compressive load. INTERPRETATION Implant geometry in combination with its material properties are very important factors to restore vertebral strength and stiffness and limiting the risk of fracture at the same vertebra or adjacent ones.
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Affiliation(s)
- Ridha Hambli
- Univ. Orléans, Univ. Tours, INSA CVL, LaMé, Orléans 45000, France.
| | - Reade De Leacy
- Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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Wu J, Feng Q, Yang D, Xu H, Wen W, Xu H, Miao J. Biomechanical evaluation of different sizes of 3D printed cage in lumbar interbody fusion-a finite element analysis. BMC Musculoskelet Disord 2023; 24:85. [PMID: 36726086 PMCID: PMC9890703 DOI: 10.1186/s12891-023-06201-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 01/27/2023] [Indexed: 02/03/2023] Open
Abstract
OBJECTIVE To study the biomechanical characteristics of various tissue structures of different sizes of 3D printed Cage in lumbar interbody fusion. METHODS A finite element model of normal spine was reconstructed and verified. Pedicle screws and Cage of different sizes were implanted in the L4/5 segment to simulate lumbar interbody fusion. The range of motion of the fixed and cephalic adjacent segment, the stress of the screw-rod system, the stress at the interface between cage and L5 endplate, and intervertebral disc pressure of the adjacent segment were calculated and analyzed. RESULTS The range of motion and intervertebral disc pressure of the adjacent segment of each postoperative model were larger than those of the intact model, but there was not much difference between them. The stress of cage-endplate interface was also larger than that of the intact model. However, the difference is that the stress of the endplate and the screw-rod system has a tendency to decrease with the increase of the axial area of cage. CONCLUSIONS Cage with larger axial area in lumbar interbody fusion can reduce the stress of internal fixation system and endplate, but will not increase the range of motion and intervertebral disc pressure of adjacent segment. It has a certain effect in preventing the cage subsidence, internal fixation system failure and screw rod fracture.
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Affiliation(s)
- Jincheng Wu
- grid.33763.320000 0004 1761 2484Department of Spine Surgery, Tianjin Hospital, Tianjin University, Jiefangnanlu 406, Hexi District, Tianjin, China
| | - Qing Feng
- grid.33763.320000 0004 1761 2484Department of Spine Surgery, Tianjin Hospital, Tianjin University, Jiefangnanlu 406, Hexi District, Tianjin, China
| | - Dongmei Yang
- grid.284723.80000 0000 8877 7471Southern Medical University, Guangzhou City, Guangdong China
| | - Hanpeng Xu
- grid.33763.320000 0004 1761 2484Department of Spine Surgery, Tianjin Hospital, Tianjin University, Jiefangnanlu 406, Hexi District, Tianjin, China
| | - Wangqiang Wen
- grid.443397.e0000 0004 0368 7493The First Affiliated Hospital of Hainan Medical University, Haikou City, Hainan China
| | - Haoxiang Xu
- The Second People’s Hospital of Hefei, Hefei, Anhui China
| | - Jun Miao
- grid.33763.320000 0004 1761 2484Department of Spine Surgery, Tianjin Hospital, Tianjin University, Jiefangnanlu 406, Hexi District, Tianjin, China
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Huang C, Liu Z, Wei Z, Fang Z, Xi Z, Cai P, Li J. Will the adjustment of insertional pedicle screw positions affect the risk of adjacent segment diseases biomechanically? An in-silico study. Front Surg 2023; 9:1004642. [PMID: 36713678 PMCID: PMC9877423 DOI: 10.3389/fsurg.2022.1004642] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 09/20/2022] [Indexed: 01/13/2023] Open
Abstract
Background The fixation-induced biomechanical deterioration will increase the risk of adjacent segment diseases (ASD) after lumbar interbody fusion with Bilateral pedicle screw (BPS) fixation. The accurate adjustment of insertional pedicle screw positions is possible, and published studies have reported its mechanical effects. However, no studies clarified that adjusting insertional screw positions would affect the postoperative biomechanical environment and the risk of ASD. The objective of this study was to identify this issue and provide theoretical references for the optimization of insertional pedicle screw position selections. Methods The oblique lumbar interbody fusion fixed by BPS with different insertional positions has been simulated in the L4-L5 segment of our previously constructed and validated lumbosacral model. Biomechanical indicators related to ASD have been computed and recorded under flexion, extension, bending, and axial rotation loading conditions. Results The change of screw insertional positions has more apparent biomechanical effects on the cranial than the caudal segment. Positive collections can be observed between the reduction of the fixation length and the alleviation of motility compensation and stress concentration on facet cartilages. By contrast, no pronounced tendency of stress distribution on the intervertebral discs can be observed with the change of screw positions. Conclusions Reducing the fixation stiffness by adjusting the insertional screw positions could alleviate the biomechanical deterioration and be an effective method to reduce the risk of ASD caused by BPS.
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Affiliation(s)
- Chenyi Huang
- Department of Orthopedics, The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, China
| | - Zongchao Liu
- Department of Orthopedics, The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, China
| | - Zhangchao Wei
- Department of Orthopedics, The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, China
| | - Zhongxin Fang
- Fluid and Power Machinery Key Laboratory of Ministry of Education, Xihua University, Chengdu, China
| | - Zhipeng Xi
- Department of Spine Surgery, Jiangsu Province Hospital on Integration of Chinese and Western Medicine, Nanjing, China
| | - Ping Cai
- Department of Orthopedics, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, China,Correspondence: Jingchi Li Ping Cai
| | - Jingchi Li
- Department of Orthopedics, The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, China,Correspondence: Jingchi Li Ping Cai
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Wu J, Han Y, Xu H, Yang D, Wen W, Xu H, Miao J. Biomechanical comparison of spinal column shortening - a finite element study. BMC Musculoskelet Disord 2022; 23:1122. [PMID: 36550443 PMCID: PMC9783724 DOI: 10.1186/s12891-022-06047-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 12/01/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND At present, research on spinal shortening is mainly focused on the safe distance of spinal shortening and the mechanism of spinal cord injury, but there is no research on the biomechanical characteristics of different shortening distances. The purpose of this study was to study the biomechanical characteristics of spine and internal fixation instruments at different shortening distances by the finite element (FE) method. METHODS An FE model of lumbar L1-S was established and referred to the previous in vitro experiments to verify the rationality of the model by verifying the Intradiscal pressure (IDP) and the range of motion (ROM) of the motion segment. Five element models of spinal shortening were designed under the safe distance of spinal shortening, and the entire L3 vertebra and both the upper and lower intervertebral discs were resected. Model A was not shortened, while models B-E were shortened by 10%, 20%, 30% and 50% of the vertebral body, respectively. Constraining the ROM of the sacrum in all directions, a 7.5 N ·m moment and 280 N follower load were applied on the L1 vertebra to simulate the motion of the lumbar vertebrae in three planes. The ROM of the operated segments, the Von Mises stress (VMS) of the screw-rod system, the VMS of the upper endplate at the interface between the titanium cage and the L4 vertebral body, and the ROM and the IDP of the adjacent segment (L5/S) were recorded and analysed. RESULTS All surgical models showed good stability at the operated segments (L1-5), with the greatest constraint in posterior extension (99.3-99.7%), followed by left-right bending (97.9-98.7%), and the least constraint in left-right rotation (84.9-86.3%) compared with the intact model. The VMS of the screw-rod system and the ROM and IDP of the distal adjacent segments of models A-E showed an increasing trend, in which the VMS of the screw-rod system of model E was the highest under flexion (172.5 MPa). The VMS of the endplate at the interface between the cage and L4 upper endplate of models A-E decreased gradually, and these trend were the most obvious in flexion, which were 3.03, 2.95, 2.83, 2.78, and 2.61 times that of the intact model, respectively. CONCLUSION When performing total vertebrae resection and correcting the spinal deformity, if the corrected spine has met our needs, the distance of spinal shortening should be minimized to prevent spinal cord injury, fracture of internal fixations and adjacent segment disease (ASD).
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Affiliation(s)
- Jincheng Wu
- grid.33763.320000 0004 1761 2484Department of Spine Surgery, Tianjin Hospital, Tianjin University, Jiefangnanlu 406, Hexi District, Tianjin, China
| | - Ye Han
- grid.459324.dThe Affiliated Hospital of Hebei University, Baoding City, Hebei China
| | - Hanpeng Xu
- grid.33763.320000 0004 1761 2484Department of Spine Surgery, Tianjin Hospital, Tianjin University, Jiefangnanlu 406, Hexi District, Tianjin, China
| | - Dongmei Yang
- grid.284723.80000 0000 8877 7471Southern Medical University, Guangzhou City, China
| | - Wangqiang Wen
- grid.443397.e0000 0004 0368 7493The First Affiliated Hospital of Hainan Medical University, Haikou City, Hainan, China
| | - Haoxiang Xu
- The Second People’s Hospital of Hefei, Hefei, Anhui, China
| | - Jun Miao
- grid.33763.320000 0004 1761 2484Department of Spine Surgery, Tianjin Hospital, Tianjin University, Jiefangnanlu 406, Hexi District, Tianjin, China
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Xu H, Wang X, Han Y, Jiang Y, Wang J, Zhang X, Miao J. Biomechanical comparison of different prosthetic reconstructions in total en bloc spondylectomy: a finite element study. BMC Musculoskelet Disord 2022; 23:955. [PMID: 36329424 PMCID: PMC9635202 DOI: 10.1186/s12891-022-05919-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 10/26/2022] [Indexed: 11/06/2022] Open
Abstract
Objective To analyse and compare the biomechanical differences between 3D-printed prostheses, titanium mesh cages and poorly matched titanium mesh cages in total en bloc spondylectomy (TES). Methods The finite element model of T10-L2 for healthy adults was modified to make three models after T12 total spondylectomy. These models were a 3D-printed prosthesis, titanium mesh cage and prosthesis-endplate mismatched titanium mesh cage for reconstruction. The range of motion (ROM), stress distribution of the endplate and internal fixation system of three models in flexion and extension, lateral bending and axial rotation were simulated and analysed by ABAQUS. Result In flexion, due to the support of the anterior prosthesis, the fixation system showed the maximum fixation strength. The fixation strength of the 3D-printed prosthesis model was 26.73 N·m /°, that of the TMC support model was 27.20 N·m /°, and that of the poorly matched TMC model was 24.16 N·m /°. In flexion, the L1 upper endplate stress of the poorly matched TMC model was 35.5% and 49.6% higher than that of the TMC and 3D-printed prosthesis, respectively. It was 17% and 28.1% higher in extension, 39.3% and 42.5% higher in lateral bending, and 82.9% and 91.2% higher in axial rotation, respectively. The lower endplate of T11 showed a similar trend, but the magnitude of the stress change was reduced. In the stress analysis of the 3D-printed prosthesis and TMC, it was found that the maximum stress was in flexion and axial rotation, followed by left and right bending, and the least stress was in extension. However, the mismatched TMC withstood the maximum von Mises stress of 418.7 MPa (almost twice as much as the buckling state) in rotation, 3 times and 5.83 times in extension, and 1.29 and 2.85 times in lateral bending, respectively. Conclusion Different prostheses with good endplate matching after total spondylectomy can obtain effective postoperative stable support, and the reduction in contact area caused by mismatch will affect the biomechanical properties and increase the probability of internal fixation failure.
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Affiliation(s)
- Hanpeng Xu
- Tianjin Hospital, Tianjin University, Tianjin, China
| | - Xiaodong Wang
- Department of Orthopaedics, Affiliated Hospital of Hebei University, Baoding, China
| | - Ye Han
- Department of Orthopaedics, Affiliated Hospital of Hebei University, Baoding, China
| | - Yuanyuan Jiang
- Department of Anesthesiology, Affiliated Hospital of Hebei University, Baoding, China
| | - Jianzhong Wang
- Department of Orthopaedics, Affiliated Hospital of Hebei University, Baoding, China
| | - Xiong Zhang
- Department of Orthopaedics, Affiliated Hospital of Hebei University, Baoding, China
| | - Jun Miao
- Tianjin Hospital, Tianjin University, Tianjin, China. .,Tianjin Hospital, Tianjin University, Jiefangnanlu 406, Hexi District, Tianjin, 300210, China.
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Wu J, Yang D, Han Y, Xu H, Wen W, Xu H, Li K, Liu Y, Miao J. Application of dual-trajectory screws in revision surgery for lumbar adjacent segment disease: a finite element study. J Orthop Surg Res 2022; 17:427. [PMID: 36153558 PMCID: PMC9509616 DOI: 10.1186/s13018-022-03317-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 09/07/2022] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Advancements in medicine and the popularity of lumbar fusion surgery have made lumbar adjacent segment disease (ASDz) increasingly common, but there is no mature plan for guiding its surgical treatment. Therefore, in this study, four different finite element (FE) ASDz models were designed and their biomechanical characteristics were analysed to provide a theoretical basis for clinical workers to choose the most appropriate revision scheme for ASDz. METHODS According to whether internal fixation was retained, different FE models were created to simulate ASDz revision surgery, and flexion, extension, axial rotation and lateral bending were simulated by loading. The biomechanical characteristics of the adjacent segments of the intervertebral disc and the internal fixation system and the range of motion (ROM) of the lumbar vertebrae were analysed. RESULTS The difference in the ROM of the fixed segment between FE models that did or did not retain the original internal fixation was less than 0.1°, and the difference was not significant. However, the stress of the screw-rod system when the original internal fixation was retained and prolonged fixation was performed with dual-trajectory screws was less than that when the original internal fixation was removed and prolonged fixation was performed with a long bar. Especially in axial rotation, the difference between models A and B is the largest, and the difference in peak stress reached 30 MPa. However, for the ASDz revision surgery segment, the endplate stress between the two models was the lowest, and the intradiscal pressure (IDP) of the adjacent segment was not significantly different between different models. CONCLUSION Although ASDz revision surgery by retaining the original internal fixation and prolonging fixation with dual-trajectory screws led to an increase in stress in the fusion segment endplate, it provides stability similar to ASDz revision surgery by removing the original internal fixation and prolonging fixation with a long bar and does not lead to a significant change in the IDP of the adjacent segment while avoiding a greater risk of rod fracture.
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Affiliation(s)
- Jincheng Wu
- grid.33763.320000 0004 1761 2484Department of Spine Surgery, Tianjin Hospital, Tianjin University, Jiefangnanlu 406, Hexi District, Tianjin, 300210 China
| | - Dongmei Yang
- grid.284723.80000 0000 8877 7471Southern Medical University, Guangzhou City, Guangdong China
| | - Ye Han
- grid.459324.dThe Affiliated Hospital of Hebei University, Baoding City, Hebei China
| | - Hanpeng Xu
- grid.33763.320000 0004 1761 2484Department of Spine Surgery, Tianjin Hospital, Tianjin University, Jiefangnanlu 406, Hexi District, Tianjin, 300210 China
| | - Wangqiang Wen
- The First Affiliated Hospital of Hainan Medical University, Haikou City, Hainan China
| | - Haoxiang Xu
- The Second People’s Hospital of Hefei, Hefei, Anhui China
| | - Kepeng Li
- Second Central Hospital of Baoding, Zhuozhou City, Hebei China
| | - Yong Liu
- Pingyao County Traditional Chinese Medicine Hospital, Jinzhong City, Shanxi China
| | - Jun Miao
- grid.33763.320000 0004 1761 2484Department of Spine Surgery, Tianjin Hospital, Tianjin University, Jiefangnanlu 406, Hexi District, Tianjin, 300210 China
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Han L, Yang H, Li Y, Li Z, Ma H, Wang C, Yuan J, Zheng L, Chen Q, Lu X. Biomechanical Evaluation of the Cross-link Usage and Position in the Single and Multiple Segment Posterior Lumbar Interbody Fusion. Orthop Surg 2022; 14:2711-2720. [PMID: 36102202 PMCID: PMC9531066 DOI: 10.1111/os.13485] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 07/28/2022] [Accepted: 08/09/2022] [Indexed: 12/29/2022] Open
Abstract
OBJECTIVE Previous studies have neither explored the usage of cross-links nor investigated the optimal position of the cross-links in posterior lumbar interbody fusion (PLIF). This study evaluates biomechanical properties of cross-links in terms of different fixation segments and optimal position in single- and multi-segment posterior lumbar interbody fusion. METHODS Two finite element (FE) models of instrumented lumbosacral spine with single-(L4/5) and multi-segment (L3-S1) PLIF surgery were simulated. On the basis of the two models, the benefits of the usage of cross-links were assessed and compared with the status of no application of cross-links. Moreover, the effects of position of cross-links on multi-segment PLIF surgery were studied in Upper, Middle, and Lower positions. RESULTS No significant difference was found in the range of motion (ROM), intersegmental rotational angle (IRA) of adjacent segments, and intradiscal pressure (IDP) regardless of the usage of cross-links in the single-segment PLIF surgery, while the cross-link increased the maximum von Mises stress in the fixation (MSF) under the axial rotation (53.65 MPa vs 41.42 MPa). In the multi-segment PLIF surgery, the usage of cross-links showed anti-rotational advantages indicated by ROM (Without Cross-link 2.35o , Upper, 2.24o ; Middle, 2.26o ; Lower, 2.30o ) and IRA (Without Cross-link 1.19o , Upper, 1.08o ; Middle, 1.09o ; Lower, 1.13o ). The greatest values of MSF were found in without cross-link case under the flexion, lateral bending, and axial rotation (37.48, 62.61, and 86.73 MPa). The application of cross-links at the Middle and Lower positions had lower values of MSF (48.79 and 69.62 MPa) under the lateral bending and axial rotation, respectively. CONCLUSION The application of cross-links was not beneficial for the single-segment PLIF, while it was found highly advantageous for the multi-segment PLIF. Moreover, the usage of cross-links at the Middle or Lower positions resulted in a better biomechanical stability.
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Affiliation(s)
- Lin Han
- Department of OrthopaedicsShanghai Changzheng Hospital, Second Military Medical UniversityShanghaiChina
| | - Haisong Yang
- Department of OrthopaedicsShanghai Changzheng Hospital, Second Military Medical UniversityShanghaiChina
| | - Yongheng Li
- Biomechanics LaboratorySchool of Biological Science & Medical Engineering, Southeast UniversityNanjingChina
| | - Zhiyong Li
- Biomechanics LaboratorySchool of Biological Science & Medical Engineering, Southeast UniversityNanjingChina,School of Mechanical Medical and Process Engineering, Queensland University of TechnologyBrisbaneAustralia
| | - Hongdao Ma
- Department of OrthopaedicsShanghai Changzheng Hospital, Second Military Medical UniversityShanghaiChina
| | - Chenfeng Wang
- Department of OrthopaedicsShanghai Changzheng Hospital, Second Military Medical UniversityShanghaiChina
| | - Jincan Yuan
- Department of OrthopaedicsShanghai Changzheng Hospital, Second Military Medical UniversityShanghaiChina
| | - Luyu Zheng
- School of Medicine, Zhengzhou UniversityZhengzhouChina
| | - Qiang Chen
- Biomechanics LaboratorySchool of Biological Science & Medical Engineering, Southeast UniversityNanjingChina
| | - Xuhua Lu
- Department of OrthopaedicsShanghai Changzheng Hospital, Second Military Medical UniversityShanghaiChina
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Nicolini LF, Beckmann A, Laubach M, Hildebrand F, Kobbe P, Mello Roesler CRD, Fancello EA, Markert B, Stoffel M. An experimental-numerical method for the calibration of finite element models of the lumbar spine. Med Eng Phys 2022; 107:103854. [DOI: 10.1016/j.medengphy.2022.103854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 05/18/2022] [Accepted: 07/18/2022] [Indexed: 11/27/2022]
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Liu ZX, Gao ZW, Chen C, Liu ZY, Cai XY, Ren YN, Sun X, Ma XL, Du CF, Yang Q. Effects of osteoporosis on the biomechanics of various supplemental fixations co-applied with oblique lumbar interbody fusion (OLIF): a finite element analysis. BMC Musculoskelet Disord 2022; 23:794. [PMID: 35986271 PMCID: PMC9392247 DOI: 10.1186/s12891-022-05645-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 07/12/2022] [Indexed: 11/25/2022] Open
Abstract
Background Oblique lumbar interbody fusion (OLIF) is an important surgical modality for the treatment of degenerative lumbar spine disease. Various supplemental fixations can be co-applied with OLIF, increasing OLIF stability and reducing complications. However, it is unclear whether osteoporosis affects the success of supplemental fixations; therefore, this study analyzed the effects of osteoporosis on various supplemental fixations co-applied with OLIF. Methods We developed and validated an L3-S1 finite element (FE) model; we assigned different material properties to each component and established models of the osteoporotic and normal bone lumbar spine. We explored the outcomes of OLIF combined with each of five supplemental fixations: standalone OLIF; OLIF with lateral plate fixation (OLIF + LPF); OLIF with translaminar facet joint fixation and unilateral pedicle screw fixation (OLIF + TFJF + UPSF); OLIF with unilateral pedicle screw fixation (OLIF + UPSF); and OLIF with bilateral pedicle screw fixation (OLIF + BPSF). Under the various working conditions, we calculated the ranges of motion (ROMs) of the normal bone and osteoporosis models, the maximum Mises stresses of the fixation instruments (MMSFIs), and the average Mises stresses on cancellous bone (AMSCBs). Results Compared with the normal bone OLIF model, no demonstrable change in any segmental ROM was apparent. The MMSFIs increased in all five osteoporotic OLIF models. In the OLIF + TFJF + UPSF model, the MMSFIs increased sharply in forward flexion and extension. The stress changes of the OLIF + UPSF, OLIF + BPSF, and OLIF + TFJF + UPSF models were similar; all stresses trended upward. The AMSCBs decreased in all five osteoporotic OLIF models during flexion, extension, lateral bending, and axial rotation. The average stress change of cancellous bone was most obvious under extension. The AMSCBs of the five OLIF models decreased by 14%, 23.44%, 21.97%, 40.56%, and 22.44% respectively. Conclusions For some supplemental fixations, the AMSCBs were all reduced and the MMSFIs were all increased in the osteoporotic model, compared with the OLIF model of normal bone. Therefore, the biomechanical performance of an osteoporotic model may be inferior to the biomechanical performance of a normal model for the same fixation method; in some instances, it may increase the risks of fracture and internal fixation failure.
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Jiang Y, Xiong X, Chen Z, Li Y. Movement posture and injury pattern of pelvis-lumbar spine of seated human impacted by the vertical high loads: a finite element analysis. Comput Methods Biomech Biomed Engin 2022; 26:835-845. [PMID: 35758223 DOI: 10.1080/10255842.2022.2091929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The injury conditions of the sitting position occupant inside the military equipment are highly related to the vertical impact environments. In this study, a detailed three-dimensional finite element (FE) model of pelvis-lumbar spine of seated human with nonlinear material property and strain failure criterion was developed and validated. A series of sinusoidal accelerations with a constant peak speed of 8 m/s and frequencies ranging from 10 Hz to 90 Hz were loaded on the FE model to investigate the injury conditions under different high loading rates. The results indicated that the injury patterns mainly include wedge fracture of the junction between lumbar spine and pelvis, and comminuted fracture of ischial tuberosity. The bending moment caused by the large angle deflection of pelvis under 10 Hz case (low rate) and the acting force caused by the excessive curvature of lumbar spine under 30 Hz-70 Hz cases (medium and high rate) cause the junction wedge fractured, while the high impact force under 30 Hz-50 Hz cases (medium rate) leads to comminuted fracture of the ischial tuberosity. The associated mechanism that the shorter the time interval between the peak of seat loading speed and the peak of hip muscle compression, the more serious dynamic responses of pelvis-lumbar spine is revealed for the first time.
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Affiliation(s)
- Yongbo Jiang
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, China.,Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing, China
| | - Xun Xiong
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, China.,Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing, China
| | - Zihao Chen
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, China.,Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing, China
| | - Ying Li
- State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing, China.,Institute of Advanced Structure Technology, Beijing Institute of Technology, Beijing, China
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Leszczynski A, Meyer F, Charles YP, Deck C, Bourdet N, Willinger R. Influence of double rods and interbody cages on range of motion and rod stress after spinopelvic instrumentation: a finite element study. EUROPEAN SPINE JOURNAL : OFFICIAL PUBLICATION OF THE EUROPEAN SPINE SOCIETY, THE EUROPEAN SPINAL DEFORMITY SOCIETY, AND THE EUROPEAN SECTION OF THE CERVICAL SPINE RESEARCH SOCIETY 2022; 31:1515-1524. [PMID: 35461384 DOI: 10.1007/s00586-022-07149-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Revised: 01/05/2022] [Accepted: 02/09/2022] [Indexed: 11/27/2022]
Abstract
PURPOSE To compare instrumentation configurations consisting of bilateral single or double rods and additional interbody cages (IBCs) at different levels in terms of Range of Motion (ROM) and distribution of von Mises stress in rods. METHODS A previously validated L1-pelvis finite element model was used and instrumented with configurations consisting of single or double bilateral rods and IBCs at multiple levels. Pure moments of 7.5 N.m were applied to L1 in main directions in addition to a follower load of 280 N. Global, segmental ROM and distribution of von Mises stress in rods were studied. RESULTS All configurations reduced segmental and global ROM from 50 to 100% compared to the intact spine. Addition of IBCs slightly increased ROM at levels adjacent to the IBC placement. The simple rod configuration presented the highest von Mises stress (457 MPa) in principal rods at L5-S1 in flexion. Doubling rods and IBC placement reduced this value and shifted the location of maximum von Mises stress to other regions. Among studied configurations, double rods with IBCs at all levels (L2-S1) showed the lowest ROM. Maximal von Mises stresses in secondary rods were lower in comparison to main rods. CONCLUSIONS Double rods and IBCs reduced global and segmental ROM as well as von Mises stress in rods. The results suggest a possible benefit in using both strategies to minimize pseudarthrosis and instrumentation failure. However, increased ROM in adjacent levels and the shift of maximal von Mises stress to adjacent areas might cause complications elsewhere.
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Affiliation(s)
- Aleksander Leszczynski
- Laboratoire ICube, UMR 7357, Unistra-CNRS, Strasbourg University, 2 Rue Boussingault, 67000, Strasbourg, France.
| | - Frank Meyer
- Laboratoire ICube, UMR 7357, Unistra-CNRS, Strasbourg University, 2 Rue Boussingault, 67000, Strasbourg, France
| | - Yann-Philippe Charles
- Service de Chirurgie du Rachis, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - Caroline Deck
- Laboratoire ICube, UMR 7357, Unistra-CNRS, Strasbourg University, 2 Rue Boussingault, 67000, Strasbourg, France
| | - Nicolas Bourdet
- Laboratoire ICube, UMR 7357, Unistra-CNRS, Strasbourg University, 2 Rue Boussingault, 67000, Strasbourg, France
| | - Rémy Willinger
- Laboratoire ICube, UMR 7357, Unistra-CNRS, Strasbourg University, 2 Rue Boussingault, 67000, Strasbourg, France
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Cai XY, Bian HM, Chen C, Ma XL, Yang Q. Biomechanical study of oblique lumbar interbody fusion (OLIF) augmented with different types of instrumentation: a finite element analysis. J Orthop Surg Res 2022; 17:269. [PMID: 35568923 PMCID: PMC9107272 DOI: 10.1186/s13018-022-03143-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 04/26/2022] [Indexed: 02/06/2023] Open
Abstract
Background To explore the biomechanical differences in oblique lumbar interbody fusion (OLIF) augmented by different types of instrumentation. Methods A three-dimensional nonlinear finite element (FE) model of an intact L3-S1 lumbar spine was built and validated. The intact model was modified to develop five OLIF surgery models (Stand-alone OLIF; OLIF with lateral plate fixation [OLIF + LPF]; OLIF with unilateral pedicle screws fixation [OLIF + UPSF]; OLIF with bilateral pedicle screws fixation [OLIF + BPSF]; OLIF with translaminar facet joint fixation + unilateral pedicle screws fixation [OLIF + TFJF + UPSF]) in which the surgical segment was L4–L5. Under a follower load of 500 N, a 7.5-Nm moment was applied to all lumbar spine models to calculate the range of motion (ROM), equivalent stress peak of fixation instruments (ESPFI), equivalent stress peak of cage (ESPC), equivalent stress peak of cortical endplate (ESPCE), and equivalent stress average value of cancellous bone (ESAVCB). Results Compared with the intact model, the ROM of the L4–L5 segment in each OLIF surgery model decreased by > 80%. The ROM values of adjacent segments were not significantly different. The ESPFI, ESPC, and ESPCE values of the OLIF + BPSF model were smaller than those of the other OLIF surgery models. The ESAVCB value of the normal lumbar model was less than the ESAVCB values of all OLIF surgical models. In most postures, the ESPFI, ESPCE, and ESAVCB values of the OLIF + LPF model were the largest. The ESPC was higher in the Stand-alone OLIF model than in the other OLIF models. The stresses of several important components of the OLIF + UPSF and OLIF + TFJF + UPSF models were between those of the OLIF + LPF and OLIF + BPSF models. Conclusions Our biomechanical FE analysis indicated the greater ability of OLIF + BPSF to retain lumbar stability, resist cage subsidence, and maintain disc height. Therefore, in the augmentation of OLIF, bilateral pedicle screws fixation may be the best approach.
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Affiliation(s)
- Xin-Yi Cai
- Department of Spine Surgery, Tianjin Hospital, Tianjin University, 406 Jiefang South Road, Hexi District, Tianjin, 300211, China.,Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, 300384, China
| | | | - Chao Chen
- Department of Spine Surgery, Tianjin Hospital, Tianjin University, 406 Jiefang South Road, Hexi District, Tianjin, 300211, China
| | - Xin-Long Ma
- Department of Spine Surgery, Tianjin Hospital, Tianjin University, 406 Jiefang South Road, Hexi District, Tianjin, 300211, China
| | - Qiang Yang
- Department of Spine Surgery, Tianjin Hospital, Tianjin University, 406 Jiefang South Road, Hexi District, Tianjin, 300211, China.
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Li JC, Xie TH, Zhang Z, Song ZT, Song YM, Zeng JC. The Mismatch Between Bony Endplates and Grafted Bone Increases Screw Loosening Risk for OLIF Patients With ALSR Fixation Biomechanically. Front Bioeng Biotechnol 2022; 10:862951. [PMID: 35464717 PMCID: PMC9023805 DOI: 10.3389/fbioe.2022.862951] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/24/2022] [Indexed: 12/26/2022] Open
Abstract
The mismatch between bony endplates (BEPs) and grafted bone (GB) triggers several complications biomechanically. However, no published study has identified whether this factor increases the risk of screw loosening by deteriorating the local stress levels. This study aimed to illustrate the biomechanical effects of the mismatch between BEP and GB and the related risk of screw loosening. In this study, radiographic and demographic data of 56 patients treated by single segment oblique lumbar interbody fusion (OLIF) with anterior lateral single rod (ALSR) fixation were collected retrospectively, and the match sufficiency between BEP and GB was measured and presented as the grafted bony occupancy rate (GBOR). Data in patients with and without screw loosening were compared; regression analyses identified independent risk factors. OLIF with different GBORs was simulated in a previously constructed and validated lumbosacral model, and biomechanical indicators related to screw loosening were computed in surgical models. The radiographic review and numerical simulations showed that the coronal plane’s GBOR was significantly lower in screw loosening patients both in the cranial and caudal vertebral bodies; the decrease in the coronal plane’s GBOR has been proven to be an independent risk factor for screw loosening. In addition, numerical mechanical simulations showed that the poor match between BEP and GB will lead to stress concentration on both screws and bone-screw interfaces. Therefore, we can conclude that the mismatch between the BEP and GB will increase the risk of screw loosening by deteriorating local stress levels, and the increase in the GBOR by modifying the OLIF cage’s design may be an effective method to optimize the patient’s prognosis.
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Affiliation(s)
- Jing-Chi Li
- Department of Orthopedic Surgery and Orthopedic Research Institute, West China Hospital/West China School of Medicine for Sichuan University, Chengdu, China
| | - Tian-Hang Xie
- Department of Orthopedic Surgery and Orthopedic Research Institute, West China Hospital/West China School of Medicine for Sichuan University, Chengdu, China
| | - Zhuang Zhang
- Department of Orthopedic Surgery and Orthopedic Research Institute, West China Hospital/West China School of Medicine for Sichuan University, Chengdu, China
| | - Zhe-Tao Song
- Department of Imaging, West China Hospital, Chengdu, China
| | - Yue-Ming Song
- Department of Orthopedic Surgery and Orthopedic Research Institute, West China Hospital/West China School of Medicine for Sichuan University, Chengdu, China
- *Correspondence: Yue-Ming Song, ; Jian-Cheng Zeng,
| | - Jian-Cheng Zeng
- Department of Orthopedic Surgery and Orthopedic Research Institute, West China Hospital/West China School of Medicine for Sichuan University, Chengdu, China
- *Correspondence: Yue-Ming Song, ; Jian-Cheng Zeng,
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Zhao G, Wang X, Liu D, Wu K, Zhao J, Fei W. A biomechanical study of ligament tethers strengthening for the prevention of proximal junctional kyphosis after posterior long-segment spinal fusion. Clin Biomech (Bristol, Avon) 2022; 94:105621. [PMID: 35299117 DOI: 10.1016/j.clinbiomech.2022.105621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 03/02/2022] [Accepted: 03/08/2022] [Indexed: 02/07/2023]
Abstract
BACKGROUND Proximal junctional kyphosis is a known complication of posterior long-segment thoracolumbar fusion. Here, the biomechanical effectiveness of ligament tethers strengthening and vertebral body augmentation, in proximal junctional kyphosis prevention was explored using the finite element analysis. METHODS Based on a validated model of T1-L5 with the pedicle screw system instrumented T8-L5, strengthening models with different strategies were created to assess the range of motion in proximal vertebrae, vertebrae stress, pedicle screw stress, and pressure on intervertebral discs during extension, flexion, lateral bending, and axial rotation motions. Strengthening strategies included two- and three-level posterior ligament tethers (TE-T7-T9 and TE-T6-T9), and tethers with T7 &T8 vertebral body augmentation (TECE-T7-T9 and TECE-T6-T9). FINDINGS Compared to the spinal fusion model, the ligament tethers strengthening significantly reduced the flexion-extension range of motion difference among the proximal vertebrae. During the flexion-extension motion, the T8 vertebra stresses in the TE-T7-T9, TE-T6-T9, TECE-T7-T9, and TECE-T6-T9 models were distinctively reduced, the values decreased by 26.8%, 28.3%, 28.8%, and 9.6%, respectively, during flexion, and by 21.9%, 35.2%, 23%, and 18.6%, respectively, during extension. In the strengthening models, the maximum stresses on the T7/T8 intervertebral disc in the TE-T6-T9 model were reduced by 13.8% during flexion and by 14.7% during extension. INTERPRETATION Based on our results, the ligament strengthening configuration of the three-level posterior tethers produced a more gradual transition in range of motion, vertebrae stresses, and intervertebral discs stress between the fused and non-fused segments, especially during flexion-extension, which may significantly decrease the proximal junctional kyphosis biomechanical risk.
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Affiliation(s)
- Gaiping Zhao
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China.
| | - Xiaoyu Wang
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Dongqing Liu
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Kunneng Wu
- School of Health Science and Engineering, University of Shanghai for Science and Technology, Shanghai, China
| | - Jian Zhao
- Department of Orthopedics, Western Theater General Hospital, Chengdu, China
| | - Wang Fei
- Chang-Hai Hospital, The Second Military Medical University, Shanghai, China
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Sun Z, Lu T, Li J, Liu J, Hu Y, Mi C. A finite element study on the effects of follower load on the continuous biomechanical responses of subaxial cervical spine. Comput Biol Med 2022; 145:105475. [PMID: 35381450 DOI: 10.1016/j.compbiomed.2022.105475] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 03/10/2022] [Accepted: 03/29/2022] [Indexed: 11/28/2022]
Abstract
In spine biomechanics, follower loads are used to mimic the in vivo muscle forces acting on a human spine. However, the effects of the follower load on the continuous biomechanical responses of the subaxial cervical spines (C2-T1) have not been systematically clarified. This study aims at investigating the follower load effects on the continuous biomechanical responses of C2-T1. A nonlinear finite element model is reconstructed and validated for C2-T1. Six levels follower loads are considered along the follower load path that is optimized through a novel range of motion-based method. A moment up to 2 Nm is subsequently superimposed to produce motions in three anatomical planes. The continuous biomechanical responses, including the range of motion, facet joint force, intradiscal pressure and flexibility are evaluated for each motion segment. In the sagittal plane, the change of the overall range of motion arising from the follower loads is less than 6%. In the other two anatomical planes, both the magnitude and shape of the rotation-moment curves change with follower loads. At the neutral position, over 50% decrease in flexibility occurs as the follower load increases from zero to 250 N. In all three anatomical planes, over 50% and 30% decreases in flexibility occur in the first 0.5 Nm for small (≤100 N) and large (≥150 N) follower loads, respectively. Moreover, follower loads tend to increase both the facet joint forces and the intradiscal pressures. The shape of the intradiscal pressure-moment curves changes from nonlinear to roughly linear with increased follower load, especially in the coronal and transverse planes. The results obtained in this work provide a comprehensive understanding on the effects of follower load on the continuous biomechanical responses of the C2-T1.
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Affiliation(s)
- Zhongwei Sun
- Jiangsu Key Laboratory of Engineering Mechanics, School of Civil Engineering, Southeast University, 2 Sipailou Street, Nanjing, 210096, Jiangsu, China
| | - Teng Lu
- Department of Orthopedics, Second Affiliated Hospital of Xi'an Jiaotong University, 30 Huangcheng West Road, Xi'an, 710004, Shaanxi, China
| | - Jialiang Li
- Department of Orthopedics, Second Affiliated Hospital of Xi'an Jiaotong University, 30 Huangcheng West Road, Xi'an, 710004, Shaanxi, China
| | - Jiantao Liu
- Department of Orthopedics, First Affiliated Hospital of Xi'an Jiaotong University, 277 Yanta West Road, Xi'an, 710061, Shaanxi, China
| | - Yuanbin Hu
- Department of Orthopedics, Zhongda Hospital, Southeast University, 2 Sipailou Street, Nanjing, 210096, Jiangsu, China.
| | - Changwen Mi
- Jiangsu Key Laboratory of Engineering Mechanics, School of Civil Engineering, Southeast University, 2 Sipailou Street, Nanjing, 210096, Jiangsu, China.
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Han L, Li Y, Li Z, Ma H, Wang C, Chen Q, Lu X. Biomechanical and Clinical Study of Rod Curvature in Single-Segment Posterior Lumbar Interbody Fusion. Front Bioeng Biotechnol 2022; 10:824688. [PMID: 35309996 PMCID: PMC8929399 DOI: 10.3389/fbioe.2022.824688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 02/07/2022] [Indexed: 11/13/2022] Open
Abstract
Objective: Pedicle screw fixation is a common technique used in posterior lumbar interbody fusion (PLIF) surgery for lumbar disorders. During operation, rod contouring is often subjective and not satisfactory, but only few studies focused on the rod-contouring issue previously. The aim of the study was to explore the effect of the rod contouring on the single-segment PLIF by the finite element (FE) method and retrospective study. Methods: A FE model of the lumbosacral vertebrae was first reconstructed, and subsequently single-segmental (L4/5) PLIF surgeries with four rod curvatures (RCs) were simulated. Herein, three RCs were designed by referring to centroid, Cobb, and posterior tangent methods applied in the lumbar lordosis measurement, and zero RC indicating straight rods was included as well. Clinical data of patients subjected to L4/5 segmental PLIF were also analyzed to verify the correlation between RCs and clinical outcome. Results: No difference was observed among the four RC models in the range of motion (ROM), intersegmental rotation angle (IRA), and intradiscal pressure (IDP) under four actions. The posterior tangent model had less maximum stress in fixation (MSF) in flexion, extension, and axial rotation than the other RC models. Patients with favorable prognosis had larger RC and positive RC minus posterior tangent angle (RC-PTA) of fused segments with respect to those who had poor prognosis and received revision surgery. Conclusion: All RC models had similar biomechanical behaviors under four actions. The posterior tangent-based RC model was superior in fixation stress distribution compared to centroid, Cobb, and straight models. The retrospective study demonstrated that moderate RC and positive RC-PTA were associated with better postoperative results.
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Affiliation(s)
- Lin Han
- Department of Orthopaedics, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Yongheng Li
- Biomechanics Laboratory, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
| | - Zhiyong Li
- Biomechanics Laboratory, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
- School of Mechanical Medical and Process Engineering, Queensland University of Technology, Brisbane, QLD, Australia
| | - Hongdao Ma
- Department of Orthopaedics, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Chenfeng Wang
- Department of Orthopaedics, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, China
| | - Qiang Chen
- Biomechanics Laboratory, School of Biological Science and Medical Engineering, Southeast University, Nanjing, China
- *Correspondence: Qiang Chen, ; Xuhua Lu,
| | - Xuhua Lu
- Department of Orthopaedics, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, China
- *Correspondence: Qiang Chen, ; Xuhua Lu,
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Cai K, Zhang Z, Luo K, Cao F, Lu B, Wu Y, Wang H, Zhang K, Jiang G. Biomechanical comparison of vertebral augmentation and cement discoplasty for the treatment of symptomatic Schmorl's node: a finite element analysis. Comput Methods Biomech Biomed Engin 2022; 25:1744-1756. [PMID: 35230207 DOI: 10.1080/10255842.2022.2036979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Percutaneous vertebral augmentation (PVA) and percutaneous cement discoplasty (PCD) are two relatively new minimally invasive surgeries for symptomatic Schmorl's reported in recent decade. However, the clinical evidence for the effectiveness of these two surgeries is insufficient. The purpose of this study was to compare the biomechanical benefits and risks of the two surgeries in order to analyze their biomechanical differences and effectiveness. We reconstructed Five lumbar finite element models via computed tomography data, including control model, PVA-ideal model, PVA-nonideal model, PCD-ideal model, and PCD-nonideal model. The stress and strain of Schmorl's nodes, bone marrow edema zone (BMEZ), affected endplate, and the overall stability of segment were analyzed and compared. The validity of our models was confirmed. As a result, the PVA-ideal model can significantly reduce the stress of Schmorl's node and the strain of BMEZ, while this effect is inappreciable in PVA-nonideal model. The PCD-ideal model significantly reduced the strain of Schmorl's nodes and BMEZ, and significantly improve segmental stability, but also resulted in a significant increase in the stress of Schmorl's nodes, BMEZ and endplates. The PCD-nonideal model not only lacks blocking effect, but also sharply increases the strain of Schmorl's nodes and BMEZ. Thus, We recommend that both PVA and PCD surgeries in ideal distribution facilitated a more stable paranodular biomechanical microenvironment. However, due to the possibility of poor biomechanical outcomes caused by the non-ideal cement distribution, the non-ideal distribution of bone cement needs to be remedied in practice.
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Affiliation(s)
- Kaiwen Cai
- Department of Orthopaedic, The Affiliated Hospital of Medical School of Ningbo University, Ningbo, PR China.,Institute of Orthopaedics, Ningbo University, Ningbo, PR China
| | - Zhang Zhang
- Department of Rheumatology, Ningbo Yinzhou No. 2 Hospital, Ningbo, PR China
| | - Kefeng Luo
- Department of Orthopaedic, The Affiliated Hospital of Medical School of Ningbo University, Ningbo, PR China.,Institute of Orthopaedics, Ningbo University, Ningbo, PR China
| | - Feng Cao
- Department of Orthopaedic, No. 906 Hospital of Chinese People's Liberation Army Joint Logistic Support Force, Ningbo, PR China
| | - Bin Lu
- Department of Orthopaedic, The Affiliated Hospital of Medical School of Ningbo University, Ningbo, PR China.,Institute of Orthopaedics, Ningbo University, Ningbo, PR China
| | - Yuanhua Wu
- Department of Radiology, The Affiliated Hospital of Medical School of Ningbo University, Ningbo, PR China
| | - Hongxia Wang
- Operating room, The Affiliated Hospital of Medical School of Ningbo University, Ningbo, PR China
| | - Kai Zhang
- Department of Orthopaedic, The Affiliated Hospital of Medical School of Ningbo University, Ningbo, PR China.,Institute of Orthopaedics, Ningbo University, Ningbo, PR China
| | - Guoqiang Jiang
- Department of Orthopaedic, The Affiliated Hospital of Medical School of Ningbo University, Ningbo, PR China.,Institute of Orthopaedics, Ningbo University, Ningbo, PR China
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Xu C, Huang C, Cai P, Fang Z, Wei Z, Liu F, Li J, Liu Y. Biomechanical Effects of Pedicle Screw Positioning on the Surgical Segment in Models After Oblique Lumbar Interbody Fusion: An in-silico Study. Int J Gen Med 2022; 15:1047-1056. [PMID: 35140507 PMCID: PMC8818966 DOI: 10.2147/ijgm.s352304] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 01/20/2022] [Indexed: 11/23/2022] Open
Abstract
Background Bilateral pedicle screw (BPS) is the “gold standard” of fixation methods for patients with lumbar interbody fusion. Biomechanical deterioration initially triggers complications in the surgical segment. Studies proved that BPS positions and trajectory changes affect the local biomechanical environment. However, no study illustrates the biomechanical effect of insertional screw positions’ change on the surgical segment. Methods Oblique lumbar interbody fusion (OLIF) with different BPS insertional positions has been simulated in a well-validated lumbo-sacral model. Fixation stability and stress responses on the surgical segment were evaluated under identical loading conditions. Results There is no clear variation tendency for the risk of BPS failure and the change of strain energy density of the grafted bone. However, shifting the insertional screw position close to the surgical segment will increase the range of motions (ROM) in the surgical segment and lead to stress concentration of bony structures, especially in the caudal side of the surgical segment. Conclusion Adjusting the insertional position of BPS close to the surgical segment in OLIF models will lead to stress concentration of bony structures and surgical segmental instability. Therefore, reducing BPS’s fixation length was not recommended, which may increase the risk of segmental instability, non-union, and cage subsidence.
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Affiliation(s)
- Chen Xu
- Department of Spine Surgery, Shanghai Changzheng Hospital, Naval Medical University, Shanghai, 200003, People’s Republic of China
| | - Chenyi Huang
- Department of Orthopedics, Hospital (T.C.M) Affiliated to Southwest Medical University, Luzhou, 646000, Sichuan, People’s Republic of China
| | - Ping Cai
- Department of Orthopedics, Affiliated Hospital of Nanjing University of Chinese Medicine, Nanjing, Jiangsu, People’s Republic of China
| | - Zhongxin Fang
- Fluid and Power Machinery Key Laboratory of Ministry of Education, Xihua University, Chengdu, People’s Republic of China
| | - Zhangchao Wei
- Department of Orthopedics, Hospital (T.C.M) Affiliated to Southwest Medical University, Luzhou, 646000, Sichuan, People’s Republic of China
| | - Fei Liu
- Department of Orthopedics, Hospital (T.C.M) Affiliated to Southwest Medical University, Luzhou, 646000, Sichuan, People’s Republic of China
| | - Jingchi Li
- Department of Spine Surgery, Shanghai Changzheng Hospital, Naval Medical University, Shanghai, 200003, People’s Republic of China
- Department of Orthopedics, Hospital (T.C.M) Affiliated to Southwest Medical University, Luzhou, 646000, Sichuan, People’s Republic of China
- Jingchi Li, Department of Orthopedics, Hospital (T.C.M) Affiliated to Southwest Medical University, No. 182, Chunhui Road, Luzhou, Sichuan Province, 646000, People’s Republic of China, Email
| | - Yang Liu
- Department of Spine Surgery, Shanghai Changzheng Hospital, Naval Medical University, Shanghai, 200003, People’s Republic of China
- Correspondence: Yang Liu, Department of Spine Surgery, Shanghai Changzheng Hospital, Naval Medical University, 415th Fengyang Road, Shanghai, 200003, People’s Republic of China, Email
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Panico M, Bassani T, Villa TMT, Galbusera F. The Simulation of Muscles Forces Increases the Stresses in Lumbar Fixation Implants with Respect to Pure Moment Loading. Front Bioeng Biotechnol 2021; 9:745703. [PMID: 34881230 PMCID: PMC8645959 DOI: 10.3389/fbioe.2021.745703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Accepted: 11/05/2021] [Indexed: 11/16/2022] Open
Abstract
Simplified loading conditions such as pure moments are frequently used to compare different instrumentation techniques to treat spine disorders. The purpose of this study was to determine if the use of realistic loading conditions such as muscle forces can alter the stresses in the implants with respect to pure moment loading. A musculoskeletal model and a finite element model sharing the same anatomy were built and validated against in vitro data, and coupled in order to drive the finite element model with muscle forces calculated by the musculoskeletal one for a prescribed motion. Intact conditions as well as a L1-L5 posterior fixation with pedicle screws and rods were simulated in flexion-extension and lateral bending. The hardware stresses calculated with the finite element model with instrumentation under simplified and realistic loading conditions were compared. The ROM under simplified loading conditions showed good agreement with in vitro data. As expected, the ROMs between the two types of loading conditions showed relatively small differences. Realistic loading conditions increased the stresses in the pedicle screws and in the posterior rods with respect to simplified loading conditions; an increase of hardware stresses up to 40 MPa in extension for the posterior rods and 57 MPa in flexion for the pedicle screws were observed with respect to simplified loading conditions. This conclusion can be critical for the literature since it means that previous models which used pure moments may have underestimated the stresses in the implants in flexion-extension and in lateral bending.
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Affiliation(s)
- Matteo Panico
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy.,IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
| | - Tito Bassani
- IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
| | - Tomaso Maria Tobia Villa
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy.,IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
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Rossman S, Meyer E, Rundell S. Development of a finite element lumbar spine model to predict intervertebral disc herniation risk factors. Comput Methods Biomech Biomed Engin 2021; 25:1-13. [PMID: 34854777 DOI: 10.1080/10255842.2021.1922677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The objective of the current study was to develop a lumbar motion segment FE model that predicts disc herniation risk. The posterolateral nucleus extrusion force and disc pressure increased as the amount of flexion and magnitude of compression was increased in all loading scenarios. The nucleus extrusion force and posterior stress in the annulus both increased when exposed to a combination of compression and flexion. Results of the current study confirmed the authors hypothesis that the model would accurately predict herniation risk when exposed to a biomechanical environment known to cause herniations.
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Affiliation(s)
- Stephanie Rossman
- Explico Engineering, Novi, MI, USA.,Mechanical Engineering Department, Lawrence Technological University, Southfield, MI, USA
| | - Eric Meyer
- Biomedical Engineering Department, Lawrence Technological University, Southfield, MI, USA
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Fan W, Zhao D, Guo LX. A finite element model of the human lower thorax to pelvis spinal segment: Validation and modal analysis. Biomed Mater Eng 2021; 32:267-279. [PMID: 33998527 DOI: 10.3233/bme-196017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Several finite element (FE) models have been developed to study the effects of vibration on human lumbar spine. However, the authors know of no published results so far that have proposed computed tomography-based FE models of whole lumbar spine including the pelvis to conduct dynamic analysis. OBJECTIVE To create and validate a three-dimensional ligamentous FE model of the human lower thorax to pelvis spinal segment (T12-Pelvis) and provide a detailed simulation environment to investigate the dynamic characteristics of the lumbar spine under whole body vibration (WBV). METHODS The T12-Pelvis model was generated based on volume reconstruction from computed tomography scans and validated against the published experimental data. FE modal analysis was implemented to predict dynamic characteristics associated with the first-order vertical resonant frequency and vibration mode of the model with upper body mass of 40 kg under WBV. RESULTS It was found that the current FE model was validated and corresponded closely with the published data. The obtained results from the modal analysis indicated that the first-order vertical resonant frequency of the T12-Pelvis model was 6.702 Hz, and the lumbar spine mainly performed vertical motion with a small anteroposterior motion. It was also found that shifting the upper body mass centroid onwards or rearwards from the normal upright sitting posture reduced the vertical resonant frequency. CONCLUSIONS These findings may be helpful to better understand vibration response of the human spine, and provide important information to minimize injury and discomfort for these WBV-exposed occupational groups.
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Affiliation(s)
- Wei Fan
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
| | - Dan Zhao
- Liaoning University of Traditional Chinese Medicine, Shenyang, China.,Liaoning Special Education Teachers College, Shenyang, China
| | - Li-Xin Guo
- School of Mechanical Engineering and Automation, Northeastern University, Shenyang, China
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50
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Jo M, Chae SW. Stress analysis of intervertebral disc during occupational activities. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 208:106298. [PMID: 34340051 DOI: 10.1016/j.cmpb.2021.106298] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 07/17/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND AND OBJECTIVE Manual material handling activities cause large compression of the intervertebral disc of the lumbar spine. Intradiscal pressure (IDP) has generally been employed to predict the risk of low back injury. As an alternative to in vivo measurements, either motion analysis or finite element (FE) analysis has been used to estimate IDP. The purpose of this study is to propose a new biomechanical method that integrates FE analysis with motion analysis, in order to estimate the stresses and deformations of the intervertebral disc of the lumbar spine during occupational activities. METHODS In the proposed method, motion analysis is performed first by using motion capture data, and the results are employed as input data to FE analysis at specific times of interest during motion. In this method, an in-house interface program is used to scale an initial reference FE model to the subject of experiment, and transformed to the corresponding posture at a specific time during motion. The muscle forces and GRF obtained from motion analysis are applied to FE analysis as boundary and loading conditions. For a total of eighteen occupational activities, the IDP, shear stress, and strain of the L4-L5 segment are estimated. RESULTS Under each in vivo activity, the predicted IDP was in overall agreement with the available in vivo data. For lifting activities according to lift origin position, the maximum IDP occurred in the far-knee position immediately after lifting. As the lift origin position moved away from the spine, the stresses and strains in the disc increased. CONCLUSIONS This new proposed method is expected to allow the estimation of the stresses and deformations in the intervertebral disc during various occupational activities.
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Affiliation(s)
- Minhye Jo
- Department of Mechanical Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea
| | - Soo-Won Chae
- Department of Mechanical Engineering, Korea University, 145, Anam-ro, Seongbuk-gu, Seoul 02841, Republic of Korea.
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