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Montanari S, Serchi E, Conti A, Barbanti Bròdano G, Stagni R, Cristofolini L. Effect of two-level decompressive procedures on the biomechanics of the lumbo-sacral spine: an ex vivo study. Front Bioeng Biotechnol 2024; 12:1400508. [PMID: 39045539 PMCID: PMC11263119 DOI: 10.3389/fbioe.2024.1400508] [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: 03/13/2024] [Accepted: 06/17/2024] [Indexed: 07/25/2024] Open
Abstract
Hemilaminectomy and laminectomy are decompressive procedures commonly used in case of lumbar spinal stenosis, which involve the removal of the posterior elements of the spine. These procedures may compromise the stability of the spine segment and create critical strains in the intervertebral discs. Thus, this study aimed to investigate if decompressive procedures could alter the biomechanics of the lumbar spine. The focus was on the changes in the range of motion and strain distribution of the discs after two-level hemilaminectomy and laminectomy. Twelve L2-S1 cadaver specimens were prepared and mechanically tested in flexion, extension and both left and right lateral bending, in the intact condition, after a two-level hemilaminectomy on L4 and L5 vertebrae, and a full laminectomy. The range of motion (ROM) of the entire segment was assessed in all the conditions and loading configurations. In addition, Digital Image Correlation was used to measure the strain distribution on the surface of each specimen during the mechanical tests, focusing on the disc between the two decompressed vertebrae and in the two adjacent discs. Hemilaminectomy did not significantly affect the ROM, nor the strain on the discs. Laminectomy significantly increased the ROM in flexion, compared to the intact state. Laminectomy significantly increased the tensile strains on both L3-L4 and L4-L5 disc (p = 0.028 and p = 0.014) in ipsilateral bending, and the compressive strains on L4-L5 intervertebral disc, in both ipsilateral and contralateral bending (p = 0.014 and p = 0.0066), with respect to the intact condition. In conclusion, this study found out that hemilaminectomy did not significantly impact the biomechanics of the lumbar spine. Conversely, after the full laminectomy, flexion significantly increased the range of motion and lateral bending was the most critical configuration for largest principal strain.
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Affiliation(s)
- Sara Montanari
- Department of Industrial Engineering, Alma Mater Studiorum—Università di Bologna, Bologna, Italy
| | - Elena Serchi
- Neurosurgery Unit, IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - Alfredo Conti
- Neurosurgery Unit, IRCCS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
- Department of Biomedical and Neuromotor Sciences (DIBINEM), Alma Mater Studiorum—Università di Bologna, Bologna, Italy
| | | | - Rita Stagni
- Department of Electrical, Electronic and Information Engineering “Guglielmo Marconi”, Alma Mater Studiorum—Università di Bologna, Bologna, Italy
| | - Luca Cristofolini
- Department of Industrial Engineering, Alma Mater Studiorum—Università di Bologna, Bologna, Italy
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Pan JH, Chen CS, Liu CL, Chou PH. Biomechanical Effects of a Novel Pedicle Screw W-Type Rod Fixation for Lumbar Spondylolysis: A Finite Element Analysis. Bioengineering (Basel) 2023; 10:bioengineering10040451. [PMID: 37106639 PMCID: PMC10136343 DOI: 10.3390/bioengineering10040451] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/19/2023] [Accepted: 04/03/2023] [Indexed: 04/29/2023] Open
Abstract
Lumbar spondylolysis involves anatomical defects of the pars interarticularis, which causes instability during motion. The instability can be addressed through instrumentation with posterolateral fusion (PLF). We developed a novel pedicle screw W-type rod fixation system and evaluated its biomechanical effects in comparison with PLF and Dynesys stabilization for lumbar spondylolysis via finite element (FE) analysis. A validated lumbar spine model was built using ANSYS 14.5 software. Five FE models were established simulating the intact L1-L5 lumbar spine (INT), bilateral pars defect (Bipars), bilateral pars defect with PLF (Bipars_PLF), Dynesys stabilization (Bipars_Dyn), and W-type rod fixation (Bipars_Wtyp). The range of motion (ROM) of the affected segment, the disc stress (DS), and the facet contact force (FCF) of the cranial segment were compared. In the Bipars model, ROM increased in extension and rotation. Compared with the INT model, Bipars_PLF and Bipars_Dyn exhibited remarkably lower ROMs for the affected segment and imposed greater DS and FCF in the cranial segment. Bipars_Wtyp preserved more ROM and generated lower stress at the cranial segment than Bipars_PLF or Bipars_Dyn. The injury model indicates that this novel pedicle screw W-type rod for spondylolysis fixation could return ROM, DS, and FCF to levels similar to preinjury.
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Affiliation(s)
- Jo-Hsi Pan
- Institute of Physical Therapy and Assistive Technology, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
- Department of Rehabilitation, Cardinal Tien Hospital, New Taipei 231, Taiwan
| | - Chen-Sheng Chen
- Institute of Physical Therapy and Assistive Technology, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
| | - Chien-Lin Liu
- Department of Orthopedic and Traumatology, Taipei Veterans General Hospital, Taipei 112, Taiwan
| | - Po-Hsin Chou
- Department of Orthopedic and Traumatology, Taipei Veterans General Hospital, Taipei 112, Taiwan
- School of Medicine, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
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Wang S, Yang D, Zheng G, Cao J, Zhao F, Shi J, You R. MRI changes of adjacent segments after transforaminal lumbar interbody fusion (TLIF) and foraminal endoscopy: A case-control study. Medicine (Baltimore) 2022; 101:e31093. [PMID: 36254062 PMCID: PMC9575806 DOI: 10.1097/md.0000000000031093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Intervertebral foramen endoscopy has developed rapidly, but compared with transforaminal lumbar interbody fusion (TLIF), the progress of degeneration is unknown. We aim to compare the changes of intervertebral disc and intervertebral foramen in adjacent segments after TLIF and endoscopic discectomy for patients with lumbar disc herniation (LDH). METHODS From 2014 to 2017, 87 patients who were diagnosed with single-level LDH and received surgery of TLIF (group T, n = 43) or endoscopic discectomy (group F, n = 44) were retrospectively analyzed. X-ray, MRI, CT and clinical symptoms were recorded before operation and at the last follow-up (FU). The neurological function was originally evaluated by the Japanese Orthopaedic Association (JOA) scores. Radiological evaluation included the height of intervertebral space (HIS), intervertebral foramen height (FH), intervertebral foramen area (FA), lumbar lordosis (CA) and intervertebral disc degeneration Pfirrmann scores. RESULTS There was no significant difference in baseline characteristics, JOA improvement rate, reoperation rate and complications between the two groups. The age, average blood loss, average hospital stays and average operation time in group F were lower than those in group T. During the last FU, HIS, CA and FA decreased in both groups, and the changes in group T were more significant than those in group F (P < .05). There was no significant difference in FH changes between the two groups (P > .05). CONCLUSION Both TLIF and endoscopic surgery can achieve good results in the treatment of LDH, but the risk of lumbar disc height loss and intervertebral foramina reduction in the adjacent segment after endoscopic surgery is lower.
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Affiliation(s)
- Shunmin Wang
- 910 Hospital of China Joint Logistics Support Force, Fujian, PR China
- Department of Orthopedic Surgery, Spine Center, Changzheng Hospital, Second Military Medical University, Shanghai, PR China
| | - Deyu Yang
- 910 Hospital of China Joint Logistics Support Force, Fujian, PR China
| | - Gengyang Zheng
- 910 Hospital of China Joint Logistics Support Force, Fujian, PR China
| | - Jie Cao
- 910 Hospital of China Joint Logistics Support Force, Fujian, PR China
| | - Feng Zhao
- 910 Hospital of China Joint Logistics Support Force, Fujian, PR China
| | - Jiangang Shi
- Department of Orthopedic Surgery, Spine Center, Changzheng Hospital, Second Military Medical University, Shanghai, PR China
- *Correspondence: Jiangang Shi, Department of Orthopedic Surgery, Spine Center, Changzheng Hospital, Second Military Medical University, No. 415 Fengyang Road, Shanghai 200003, PR ChinaRuijin You, 910 Hospital of China Joint Logistics Support Force, 180 Garden Road, Fengze District, Quanzhou City, Fujian Provice, PR China (e-mail: )
| | - Ruijin You
- 910 Hospital of China Joint Logistics Support Force, Fujian, PR China
- *Correspondence: Jiangang Shi, Department of Orthopedic Surgery, Spine Center, Changzheng Hospital, Second Military Medical University, No. 415 Fengyang Road, Shanghai 200003, PR ChinaRuijin You, 910 Hospital of China Joint Logistics Support Force, 180 Garden Road, Fengze District, Quanzhou City, Fujian Provice, PR China (e-mail: )
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Fan W, Guo LX. Biomechanical investigation of topping-off technique using an interspinous process device following lumbar interbody fusion under vibration loading. Med Biol Eng Comput 2021; 59:2449-2458. [PMID: 34671891 DOI: 10.1007/s11517-021-02458-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 10/14/2021] [Indexed: 11/25/2022]
Abstract
Topping-off technique has been proposed to prevent adjacent-segment degeneration/disease following spine fusion surgery. Nevertheless, few studies have investigated biomechanics of the fusion surgery with topping-off device under whole-body vibration (WBV). This biomechanical study aimed to investigate the vibration characteristics of human lumbar spine after topping-off surgery, and also to evaluate the effect of bony fusion on spine biomechanics. Based on a healthy finite-element model of lumbosacral spine (L1-sacrum), the models of topping-off surgery before and after bony fusion were developed. The simulated surgical procedures consisted of interbody fusion with rigid stabilizer at L4-L5 segment (rigid fusion) and dynamic stabilizer at degenerated L3-L4 segment. An interspinous implant, Device for Intervertebral Assisted Motion (DIAM, Medtronic Inc., Minnesota, USA), was used as the dynamic stabilizer. The stress responses of spine segments and implants under a vertical cyclic load were calculated and analyzed. The results showed that compared with rigid fusion alone, the topping-off technique significantly decreased disc stress at transition segment (L3-L4) as expected, and resulted in a slight increase in disc stress at its supra-adjacent segment (L2-L3). It indicated that the topping-off stabilization using DIAM might provide a good tradeoff between protection of transition segment and deterioration of its supra-adjacent segment during WBV. Also, it was found that bony fusion decreased stress in L4 inferior endplate and rigid stabilizer but had nearly no effect on stress in DIAM and L3-L4 disc, which was helpful to determine the biomechanical differences before and after bony fusion.
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Affiliation(s)
- Wei Fan
- School of Mechanical Engineering and Automation, Northeastern University, No. 3-11, Wenhua Road, Heping District, Shenyang, 110819, China.
| | - Li-Xin Guo
- School of Mechanical Engineering and Automation, Northeastern University, No. 3-11, Wenhua Road, Heping District, Shenyang, 110819, China
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Kasai Y, Paholpak P, Nabudda K, Wisanuyotin T, Sirichativapee W, Kosuwon W, Mizuno T, Kato T. Pedicle Screw System May Not Control Severe Spinal Rotational Instability. Spine (Phila Pa 1976) 2020; 45:E1386-E1390. [PMID: 32796462 DOI: 10.1097/brs.0000000000003619] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN An in vitro biomechanical study. OBJECTIVE The purpose of this study is to discuss whether pedicle screw systems can control spinal rotational instability in a functional spinal unit of lumbar spine on human cadaver. SUMMARY OF BACKGROUND DATA Rotational experiments using deer lumbar cadaveric models showed that rotational range of motion (ROM) of the model fixed by a pedicle screw system with crosslinking after total facetectomy for both the sides was larger than that in the intact model, and stated that spinal rotational instability could not be controlled using a pedicle screw system. METHODS A rotation experiment using 10 functional spinal units (L3-4) of lumbar spine on human cadavers was performed by preparing the four models (intact model, damaged model, pedicle screw model, and crosslink (CL) model) in stages, then calculating and comparing rotational ROM among the four models. RESULTS Rotational ROM in the CL model was still larger than that of the intact model in all the samples. And, rotational ROM decreased in the order of damaged model >> pedicle screw model > CL model > intact model. Statistical analysis revealed significant differences between all models (P < 0.001). CONCLUSIONS Pedicle screw systems may not control severe spinal rotational instability in human lumbar cadaveric models with total facetectomy on both the sides. This may represent a major biomechanical drawback to the pedicle screw system. LEVEL OF EVIDENCE N/A.
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Affiliation(s)
- Yuichi Kasai
- Department of Orthopaedics, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Permsak Paholpak
- Department of Orthopaedics, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Kriengkrai Nabudda
- Department of Mechanical Engineering, Faculty of Engineering, Khon Kaen University, Khon Kaen, Thailand
| | - Taweechok Wisanuyotin
- Department of Orthopaedics, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Winai Sirichativapee
- Department of Orthopaedics, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Weerachai Kosuwon
- Department of Orthopaedics, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Tetsutaro Mizuno
- Department of Orthopaedic Surgery, Seirei Hamamatsu General Hospital, Shizuoka, Japan
| | - Takaya Kato
- Graduate School of Regional Innovation Studies, Mie University, Mie, Japan
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Hsieh YY, Tsuang FY, Kuo YJ, Chen CH, Chiang CJ, Lin CL. Biomechanical analysis of single-level interbody fusion with different internal fixation rod materials: a finite element analysis. BMC Musculoskelet Disord 2020; 21:100. [PMID: 32059656 PMCID: PMC7023693 DOI: 10.1186/s12891-020-3111-1] [Citation(s) in RCA: 12] [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: 09/04/2019] [Accepted: 02/03/2020] [Indexed: 12/11/2022] Open
Abstract
Background Lumbar spinal fusion with rigid spinal fixators as one of the high risk factors related to adjacent-segment failure. The purpose of this study is to investigate how the material properties of spinal fixation rods influence the biomechanical behavior at the instrumented and adjacent levels through the use of the finite element method. Methods Five finite element models were constructed in our study to simulate the human spine pre- and post-surgery. For the four post-surgical models, the spines were implanted with rods made of three different materials: (i) titanium rod, (ii) PEEK rod with interbody PEEK cage, (iii) Biodegradable rod with interbody PEEK cage, and (iv) PEEK cage without pedicle screw fixation (no rods). Results Fusion of the lumbar spine using PEEK or biodegradable rods allowed a similar ROM at both the fusion and adjacent levels under all conditions. The models with PEEK and biodegradable rods also showed a similar increase in contact forces at adjacent facet joints, but both were less than the model with a titanium rod. Conclusions Flexible rods or cages with non-instrumented fusion can mitigate the increased contact forces on adjacent facet joints typically found following spinal fixation, and could also reduce the level of stress shielding at the bone graft.
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Affiliation(s)
- Yueh-Ying Hsieh
- Department of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan.,Department of Orthopedics, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan.,Department of Orthopedic Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Fon-Yih Tsuang
- Division of Neurosurgery, Department of Surgery, National Taiwan University Hospital, Taipei, Taiwan.,Department of Traumatology, National Taiwan University Hospital, Taipei, Taiwan.,Institute of Biomedical Engineering, National Taiwan University, Taipei, Taiwan
| | - Yi-Jie Kuo
- Department of Orthopedic Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Department of Orthopedic Surgery, Taipei Municipal Wanfang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Chia-Hsien Chen
- Department of Orthopedic Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.,Graduate Institute of Biomedical Materials and Tissue Engineering, College of Biomedical Engineering, Taipei Medical University, Taipei, Taiwan
| | - Chang-Jung Chiang
- Department of Orthopedics, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan. .,Department of Orthopedic Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan.
| | - Chun-Li Lin
- Department of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan.
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Zhu ZQ, Duan S, Wang KF, Liu HY, Xu S, Liu CJ. Biomechanical effect of bone resorption of the spinous process after single-segment interspinous dynamic stabilization device implantation: A finite element analysis. Medicine (Baltimore) 2018; 97:e11140. [PMID: 29979380 PMCID: PMC6076163 DOI: 10.1097/md.0000000000011140] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
This study aims to explore the influence of bone resorption of the spinous process after single-segment interspinous process device (IPD) implantation on the biomechanics of the lumbar spine.The 3D finite element model of the lumbar spine (L3-L5) was modified, and 2 models that simulated the presence and absence of bone resorption of the spinous process were developed using an IPD (Wallis). Its biomechanical effects, such as change in range of motion (ROM) and intervertebral disc and facet stress, were introduced at operative (L4/5) and adjacent (L3/4) levels.Compared with the INT model, the Wallis model and Wallis-BR model had similar ROMs in lateral flexion and rotation. However, the Wallis model had a lower L3-5 ROM in flexion (20.4% lower) and extension (26.4% lower), and L4-L5 ROM in flexion (74.1% lower) and extension (70.8% lower), while the overall ROM of the Wallis-BR model was greater than that of the Wallis model. The stress on the L3/L4 intervertebral disc and facets was similar for all 3 models. Compared with the INT model and Wallis-BR model, the stress on the L4/L5 intervertebral disc and facets under all movements significantly decreased in the Wallis model. The stress on the L5 process was greater than that on the L4 process in both the Wallis model and Wallis-BR model, and the load on the processes that underwent bone resorption was lower than that of the Wallis model.The function of the IPD slowly decreased with the occurrence of bone resorption of the interspinous process. This bone remodeling may be associated with high stress after IPD implantation.
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The primary stability of different implants for intra-articular calcaneal fractures: an in vitro study. Biomed Eng Online 2018; 17:50. [PMID: 29716591 PMCID: PMC5930824 DOI: 10.1186/s12938-018-0484-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2017] [Accepted: 04/23/2018] [Indexed: 11/25/2022] Open
Abstract
Background Calcaneal fractures account for around 2% of all fractures and most of them are intra-articular fractures. Many implants have been used in the fixation of calcaneal fractures, but their biomechanical stability has not yet been well investigated. The aim of this study was to compare the primary stability of four fixations of calcaneal fracture. Methods Eight cadaveric calcaneus samples were used to simulate the Sanders’ types III fracture pattern and fixed through four different implants, namely, K-wires, cannulated screws (CS), absorbable screws (AS), and plate-screw system (PSS). Each specimen was then placed into a custom-made jig and was loaded through a material testing machine to simulate the physiological condition. The primary stability was measured in the vertical direction as the stiffness and anterior–posterior direction as the calcaneocuboid force. One-way analysis of variance was used for data analysis. Results The results showed the highest stiffness of 634 (383–891; SD 226) N/mm in the intact model. It was significantly higher than the models fixed with K-wires, CS or PSS. There was no significant difference in vertical stiffness between fractures fixed with AS and the intact model or other fixed models. The intact model showed the lowest calcaneocuboid force of 153 (120–218; SD 39) N, while the fractures fixed with AS showed the greatest force of 242 (146–398; SD 84) N. The significance was only detected between these two models. Conclusions The global stiffness was similar when the calcaneal fractures were fixed by K-wires, CS and PSS. The stability of the AS fixation differed along both the vertical and anterior–posterior directions, and was greatly influenced by the bone quality. AS for fracture fixation should be designed with greater strength and pull-out resistance.
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Biomechanical properties of different techniques used in vitro for suturing mid-substance Achilles tendon ruptures. Clin Biomech (Bristol, Avon) 2017; 50:78-83. [PMID: 29032307 DOI: 10.1016/j.clinbiomech.2017.10.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Revised: 08/18/2017] [Accepted: 10/07/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND The Dresden technique preserves the paratenon during Achilles tendon repair and may improve the plantarflexor mechanism when combined with mobilization during early rehabilitation. However, the surgical repair design for Achilles tendon ruptures can affect rates of re-rupture or lengthening. Therefore, the aim of this study was to determine the biomechanical properties of the Krackow, Double-Kessler, Double-Dresden, and Triple-Dresden techniques used for repairing mid-substance Achilles tendon ruptures during cyclical and maximum traction. METHODS Sixty mid-substance bovine tendons repaired after transverse rupturing were divided randomly into four groups by repair technique: Krackow, Double-Kessler, Double-Dresden, and Triple-Dresden. Cyclical tractions of 4.7, 5.8, 7.9, and 11.7mm (equivalent to 5°, 8°, 10°, and 15° of dorsal flexion, respectively) were applied to determine gapping, tensile strength, nominal suture stress, repair deformation, and specimens with clinical failure (gap>5mm). Maximal traction was applied to measure maximum strength and failure type (i.e. suture, knot, or tendon). FINDINGS The Triple-Dresden technique resulted in decreased gapping, nominal suture stress, repair deformation, and quantity of specimens with clinical failure as compared to the other techniques. Furthermore, Triple-Dresden tendons showed greater comparative tensile and maximum strength. During maximal traction testing, this technique presented tendon failure, whereas the Krackow, Double-Kessler, and Double-Dresden techniques had suture failures. INTERPRETATION Triple-Dresden repair results in better cyclical and maximum traction strengths, suggesting that this technique might be more appropriate when performing early mobilization after mid-substance Achilles tendon rupture repair.
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Assessment of the suitability of biodegradable rods for use in posterior lumbar fusion: An in-vitro biomechanical evaluation and finite element analysis. PLoS One 2017; 12:e0188034. [PMID: 29145437 PMCID: PMC5690668 DOI: 10.1371/journal.pone.0188034] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2017] [Accepted: 10/29/2017] [Indexed: 02/06/2023] Open
Abstract
Interbody fusion with posterior instrumentation is a common method for treating lumbar degenerative disc diseases. However, the high rigidity of the fusion construct may produce abnormal stresses at the adjacent segment and lead to adjacent segment degeneration (ASD). As such, biodegradable implants are becoming more popular for use in orthopaedic surgery. These implants offer sufficient stability for fusion but at a reduced stiffness. Tailored to degrade over a specific timeframe, biodegradable implants could potentially mitigate the drawbacks of conventional stiff constructs and reduce the loading on adjacent segments. Six finite element models were developed in this study to simulate a spine with and without fixators. The spinal fixators used both titanium rods and biodegradable rods. The models were subjected to axial loading and pure moments. The range of motion (ROM), disc stresses, and contact forces of facet joints at adjacent segments were recorded. A 3-point bending test was performed on the biodegradable rods and a dynamic bending test was performed on the spinal fixators according to ASTM F1717-11a. The finite element simulation showed that lumbar spinal fusion using biodegradable implants had a similar ROM at the fusion level as at adjacent levels. As the rods degraded over time, this produced a decrease in the contact force at adjacent facet joints, less stress in the adjacent disc and greater loading on the anterior bone graft region. The mechanical tests showed the initial average fatigue strength of the biodegradable rods was 145 N, but this decreased to 115N and 55N after 6 months and 12 months of soaking in solution. Also, both the spinal fixator with biodegradable rods and with titanium rods was strong enough to withstand 5,000,000 dynamic compression cycles under a 145 N axial load. The results of this study demonstrated that biodegradable rods may present more favourable clinical outcomes for lumbar fusion. These polymer rods could not only provide sufficient initial stability, but the loss in rigidity of the fixation construct over time gradually transfers loading to adjacent segments.
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Arndt C, Görgner A, Klöhn C, Scholz R, Voigt C. Shear stress and von Mises stress distributions in the periphery of an embedded acetabular cup implant during impingement. BIOMED ENG-BIOMED TE 2017; 62:279-288. [PMID: 27505082 DOI: 10.1515/bmt-2016-0107] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 07/05/2016] [Indexed: 11/15/2022]
Abstract
As literature implies, daily activities of total hip arthroplasty (THA) patients may include movements prone to implant-implant impingement. Thus, high shear stresses may be induced at the acetabular implant-bone interface, increasing the risk of implant loosening. The aim of the current study is to determine whether or not impingement events may pose an actual risk to acetabular periprosthetic bone. An existing experimental workflow was augmented to cover complete three-dimensional strain gage measurement. von Mises and shear stresses were calculated from 1620 measured strain values, collected around a hemispherical cup implant at 2.5 mm interface distance during worst-case impingement loading. A shear stress criterion for acetabular periprosthetic bone was derived from the literature. At the impingement site, magnitudes of von Mises stress amount to 0.57 MPa and tilting shear stress amount to -0.3 MPa at 2.5 mm interface distance. Conclusion can be drawn that worst-case impingement events are unlikely to pose a risk of bone material failure in the periphery around fully integrated cementless acetabular hip implants in otherwise healthy THA patients. As numerical predictions in the literature suggested, it can now be confirmed that impingement moments are unlikely to cause acetabular implant-bone interface fixation failures.
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Fu L, Ma J, Lu B, Jia H, Zhao J, Kuang M, Feng R, Xu L, Bai H, Sun L, Wang Y, Ma X. Biomechanical effect of interspinous process distraction height after lumbar fixation surgery: An in vitro model. Proc Inst Mech Eng H 2017; 231:663-672. [PMID: 28410566 DOI: 10.1177/0954411917700446] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Pedicle screw fixation may induce abnormal activity at adjacent segment and accelerate the degeneration of lumbar vertebrae. Dynamic stabilizers could provide an intermediate solution between conservative treatment and fusion surgery. Lumbar vertebral segment cephalad to instrumented fixation was the most common localization of adjacent segment degeneration. The aim of this study is to explore the use of interspinous process devices in the lumbar vertebral segment cephalad to fixation segment in changing the mechanical distribution and limiting abnormal activity of the spine. Eight specimens were tested in the following groups: intact group, instability group (bilateral facetectomy at L3-L4), fixation group (bilateral facetectomy and pedicle screw fixation at L3-L4), and hybrid fixation group (fixation at L3-L4 and simulating interspinous device implantation of 6, 8, 10, 12, 14, 16, and 18 mm at L2-L3). Range of motion, motion of vertebral body, and strain distribution change were recorded. The range of motion in extension with 16- and 18-mm hybrid constructs was significantly lower than intact, instability, and fixation groups. In flexion and lateral bending, the strain values of L4 inferior articular process with 18-mm hybrid construct have a significant difference compared with other groups. In axial rotation, under the condition of a contralateral state, the strain values of L2 superior articular process with 18-mm hybrid construct have a significant difference compared with intact and fixation groups. The strain value of the L4 inferior articular process had negative correlation with height distraction in three dimensions, except extension. A negative correlation between the strain value of the L2 superior articular process and distraction height was found in contralateral bending and contralateral axial rotation. Interspinous process devices above the fixation segment can change the mechanical distribution of the spine and limit activity in some of the segments of the spine, which may delay the degeneration of the adjacent segment.
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Affiliation(s)
- Lin Fu
- 1 General Hospital, Tianjin Medical University, Tianjin, China
| | - Jianxiong Ma
- 2 Orthopaedics Research Institute, Tianjin Hospital Heping Branch, Tianjin, China
| | - Bin Lu
- 2 Orthopaedics Research Institute, Tianjin Hospital Heping Branch, Tianjin, China
| | - Haobo Jia
- 2 Orthopaedics Research Institute, Tianjin Hospital Heping Branch, Tianjin, China
| | - Jie Zhao
- 2 Orthopaedics Research Institute, Tianjin Hospital Heping Branch, Tianjin, China
| | - Mingjie Kuang
- 2 Orthopaedics Research Institute, Tianjin Hospital Heping Branch, Tianjin, China
| | - Rui Feng
- 2 Orthopaedics Research Institute, Tianjin Hospital Heping Branch, Tianjin, China
| | - Liyan Xu
- 2 Orthopaedics Research Institute, Tianjin Hospital Heping Branch, Tianjin, China
| | - Haohao Bai
- 2 Orthopaedics Research Institute, Tianjin Hospital Heping Branch, Tianjin, China
| | - Lei Sun
- 2 Orthopaedics Research Institute, Tianjin Hospital Heping Branch, Tianjin, China
| | - Ying Wang
- 2 Orthopaedics Research Institute, Tianjin Hospital Heping Branch, Tianjin, China
| | - Xinlong Ma
- 2 Orthopaedics Research Institute, Tianjin Hospital Heping Branch, Tianjin, China
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Tuan Dao T. Hybrid Rigid-Deformable Model for Prediction of Neighboring Intervertebral Disk Loads During Flexion Movement After Lumbar Interbody Fusion at L3-4 Level. J Biomech Eng 2017; 139:2594573. [PMID: 27996077 DOI: 10.1115/1.4035483] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Indexed: 11/08/2022]
Abstract
Knowledge of spinal loads in neighboring disks after interbody fusion plays an important role in the clinical decision of this treatment as well as in the elucidation of its effect. However, controversial findings are still noted in the literature. Moreover, there are no existing models for efficient prediction of intervertebral disk stresses within annulus fibrosus (AF) and nucleus pulposus (NP) regions. In this present study, a new hybrid rigid-deformable modeling workflow was established to quantify the mechanical stress behaviors within AF and NP regions of the L1-2, L2-3, and L4-5 disks after interbody fusion at L3-4 level. The changes in spinal loads were compared with results of the intact model without interbody fusion. The fusion outcomes revealed maximal stress changes (10%) in AF region of L1-2 disk and in NP region of L2-3 disk. The minimal stress change (1%) is noted at the NP region of the L1-2 disk. The validation of simulation outcomes of fused and intact lumbar spine models against those of other computational models and in vivo measurements showed good agreements. Thus, this present study may be used as a novel design guideline for a specific implant and surgical scenario of the lumbar spine disorders.
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Affiliation(s)
- Tien Tuan Dao
- Sorbonne University, Université de Technologie de Compiègne, CNRS, UMR 7338 Biomechanics and Bioengineering, Centre de Recherche Royallieu, Compiègne CS 60 319, France e-mail:
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14
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Huang YP, Du CF, Cheng CK, Zhong ZC, Chen XW, Wu G, Li ZC, Ye JD, Lin JH, Wang LZ. Preserving Posterior Complex Can Prevent Adjacent Segment Disease following Posterior Lumbar Interbody Fusion Surgeries: A Finite Element Analysis. PLoS One 2016; 11:e0166452. [PMID: 27870867 PMCID: PMC5117648 DOI: 10.1371/journal.pone.0166452] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 10/29/2016] [Indexed: 11/28/2022] Open
Abstract
Objective To investigate the biomechanical effects of the lumbar posterior complex on the adjacent segments after posterior lumbar interbody fusion (PLIF) surgeries. Methods A finite element model of the L1–S1 segment was modified to simulate PLIF with total laminectomy (PLIF-LAM) and PLIF with hemilaminectomy (PLIF-HEMI) procedures. The models were subjected to a 400N follower load with a 7.5-N.m moment of flexion, extension, torsion, and lateral bending. The range of motion (ROM), intradiscal pressure (IDP), and ligament force were compared. Results In Flexion, the ROM, IDP and ligament force of posterior longitudinal ligament, intertransverse ligament, and capsular ligament remarkably increased at the proximal adjacent segment in the PLIF-LAM model, and slightly increased in the PLIF-HEMI model. There was almost no difference for the ROM, IDP and ligament force at L5-S1 level between the two PLIF models although the ligament forces of ligamenta flava remarkably increased compared with the intact lumbar spine (INT) model. For the other loading conditions, these two models almost showed no difference in ROM, IDP and ligament force on the adjacent discs. Conclusions Preserved posterior complex acts as the posterior tension band during PLIF surgery and results in less ROM, IDP and ligament forces on the proximal adjacent segment in flexion. Preserving the posterior complex during decompression can be effective on preventing adjacent segment degeneration (ASD) following PLIF surgeries.
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Affiliation(s)
- Yun-Peng Huang
- Department of Orthopaedics, The First Affiliated Hospital of Fujian Medical University, Fuzhou City, Fujian Province, 350005, China
| | - Cheng-Fei Du
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, Tianjin University of Technology, Tianjin, 300384, China
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, International Research Center for Implantable and Interventional Medical Devices, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100191, China
| | - Cheng-Kung Cheng
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, International Research Center for Implantable and Interventional Medical Devices, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100191, China
- Orthopaedic Device Research Center, National Yang-Ming University, 11221, Taipei, China
| | - Zheng-Cheng Zhong
- Orthopaedic Device Research Center, National Yang-Ming University, 11221, Taipei, China
| | - Xuan-Wei Chen
- Department of Orthopaedics, The First Affiliated Hospital of Fujian Medical University, Fuzhou City, Fujian Province, 350005, China
| | - Gui Wu
- Department of Orthopaedics, The First Affiliated Hospital of Fujian Medical University, Fuzhou City, Fujian Province, 350005, China
| | - Zhe-Cheng Li
- Department of Orthopaedics, The First Affiliated Hospital of Fujian Medical University, Fuzhou City, Fujian Province, 350005, China
| | - Jin-Duo Ye
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, Tianjin University of Technology, Tianjin, 300384, China
| | - Jian-Hua Lin
- Department of Orthopaedics, The First Affiliated Hospital of Fujian Medical University, Fuzhou City, Fujian Province, 350005, China
- * E-mail: (JHL); (LZW)
| | - Li Zhen Wang
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, International Research Center for Implantable and Interventional Medical Devices, School of Biological Science and Medical Engineering, Beihang University, Beijing, 100191, China
- * E-mail: (JHL); (LZW)
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15
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Provaggi E, Leong JJH, Kalaskar DM. Applications of 3D printing in the management of severe spinal conditions. Proc Inst Mech Eng H 2016; 231:471-486. [PMID: 27658427 DOI: 10.1177/0954411916667761] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The latest and fastest-growing innovation in the medical field has been the advent of three-dimensional printing technologies, which have recently seen applications in the production of low-cost, patient-specific medical implants. While a wide range of three-dimensional printing systems has been explored in manufacturing anatomical models and devices for the medical setting, their applications are cutting-edge in the field of spinal surgery. This review aims to provide a comprehensive overview and classification of the current applications of three-dimensional printing technologies in spine care. Although three-dimensional printing technology has been widely used for the construction of patient-specific anatomical models of the spine and intraoperative guide templates to provide personalized surgical planning and increase pedicle screw placement accuracy, only few studies have been focused on the manufacturing of spinal implants. Therefore, three-dimensional printed custom-designed intervertebral fusion devices, artificial vertebral bodies and disc substitutes for total disc replacement, along with tissue engineering strategies focused on scaffold constructs for bone and cartilage regeneration, represent a set of promising applications towards the trend of individualized patient care.
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Affiliation(s)
- Elena Provaggi
- 1 Centre for Nanotechnology & Tissue Engineering, Division of Surgery and Interventional Science, UCL Medical School, University College London, London, UK
| | - Julian J H Leong
- 1 Centre for Nanotechnology & Tissue Engineering, Division of Surgery and Interventional Science, UCL Medical School, University College London, London, UK.,2 Royal National Orthopaedic Hospital, Stanmore, UK
| | - Deepak M Kalaskar
- 1 Centre for Nanotechnology & Tissue Engineering, Division of Surgery and Interventional Science, UCL Medical School, University College London, London, UK
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16
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Zeng ZL, Jia L, Xu W, Yu Y, Hu X, Jia YW, Wang JJ, Cheng LM. Analysis of risk factors for adjacent superior vertebral pedicle-induced facet joint violation during the minimally invasive surgery transforaminal lumbar interbody fusion: a retrospective study. Eur J Med Res 2015; 20:80. [PMID: 26399320 PMCID: PMC4581410 DOI: 10.1186/s40001-015-0174-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 09/14/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The purpose was to explore possible risk factors of facet joint violation induced by adjacent superior vertebral pedicle screw during the minimally invasive surgery transforaminal lumbar interbody fusion (MIS-TLIF). METHODS A total of 69 patients with lumbar degenerative disease, who underwent MIS-TLIF were retrospectively reviewed. Postoperative computed tomography images were used to assess the facet joint violation. The correlation of facet joint violations with gender, age, body mass index (BMI), the adjacent superior vertebral level, fusion segment numbers, position of screw insertion, straight leg-raising test (SLRT) results, clinical diseases and renal dysfunction were analyzed by Chi-square tests and binary logistic regression analysis. RESULTS The incidence of adjacent superior facet joint violations was 25.4 %. Chi-square test showed the patients with age <60 and high BMI (≥30 kg/m(2)) were more prone to have facet joint violations (P = 0.007; P = 0.006). The single segment fusion presented more facet joint violations than the double segments fusion (P = 0.048). The vertebral pedicle screw implant location at L5 showed more facet joint violations compared with that at L3 and L4 (P = 0.035). No correlation was found between gender, screw implant position, SLRT results, clinical diseases and renal dysfunction and facet joint violations. Logistic regression analysis revealed that age <60 years (OR: 2.902; 95 % CI 1.227-6.864; P = 0.015) and BMI ≥30 kg/m(2) (OR: 2.825; 95 % CI 1.191-6.700; P = 0.018 < 0.05) were significantly associated with facet joint violation. CONCLUSION These results found a high incidence of adjacent superior vertebral facet joint violation in the MIS-TLIF. Age <60 and BMI ≥30 kg/m(2) might be risk factors of facet joint violation. Evidence level: Level 4.
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Affiliation(s)
- Zhi-Li Zeng
- Department of Spine Surgery, Tongji Hospital, Tongji University School of Medicine, 389 Xincun Road, Shanghai, China.
| | - Long Jia
- Department of Spine Surgery, Tongji Hospital, Tongji University School of Medicine, 389 Xincun Road, Shanghai, China.
| | - Wei Xu
- Department of Spine Surgery, Tongji Hospital, Tongji University School of Medicine, 389 Xincun Road, Shanghai, China.
| | - Yan Yu
- Department of Spine Surgery, Tongji Hospital, Tongji University School of Medicine, 389 Xincun Road, Shanghai, China.
| | - Xiao Hu
- Department of Spine Surgery, Tongji Hospital, Tongji University School of Medicine, 389 Xincun Road, Shanghai, China.
| | - Yong-Wei Jia
- Department of Spine Surgery, Tongji Hospital, Tongji University School of Medicine, 389 Xincun Road, Shanghai, China.
| | - Jian-Jie Wang
- Department of Spine Surgery, Tongji Hospital, Tongji University School of Medicine, 389 Xincun Road, Shanghai, China.
| | - Li-Ming Cheng
- Department of Spine Surgery, Tongji Hospital, Tongji University School of Medicine, 389 Xincun Road, Shanghai, China.
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