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Tsukamoto M, Morimoto T, Yoshihara T, Hirata H, Toda Y, Kobayashi T, Mawatari M. Traction Spurs in the Lumbar Spine: A Historical Overview and Future Perspectives. Spine Surg Relat Res 2024; 8:354-361. [PMID: 39131417 PMCID: PMC11310535 DOI: 10.22603/ssrr.2023-0214] [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: 09/27/2023] [Accepted: 12/04/2023] [Indexed: 08/13/2024] Open
Abstract
Numerous studies have explored the connection between lumbar osteophytes, their pathophysiology, and instability since Macnab's 1971 report on traction spurs as an indicator of lumbar instability. This study provides a narrative historical overview of traction spurs, a classic finding that suggests lumbar instability. It summarizes the causes of anterior lumbar vertebral osteophytes, the relationship between traction spurs and lumbar spinal instability, and the clinical significance of traction spurs. Vertebral osteophytes are grouped into two categories, namely, traction spurs or claw spurs, which represent different stages of the same pathological process. Traction spurs are indicative of instability and occur in the early stage of disc degeneration, characterized by temporary dysfunction or instability. Traction spur formation following fusion surgery can predict union or nonunion, and it serves as an indicator of preoperative and postoperative segmental instability. The relationship between traction spurs and radiographic instability, as well as their association with imaging findings such as CT and MRI, has been clarified. Additionally, finite element analysis and mechanical testing have been used to investigate the significance of traction spurs. However, further research is needed to verify that traction spurs are an accurate indicator of pre- and postoperative lumbar instability.
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Affiliation(s)
- Masatsugu Tsukamoto
- Department of Orthopedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Tadatsugu Morimoto
- Department of Orthopedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Tomohito Yoshihara
- Department of Orthopedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Hirohito Hirata
- Department of Orthopedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Yu Toda
- Department of Orthopedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Takaomi Kobayashi
- Department of Orthopedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
| | - Masaaki Mawatari
- Department of Orthopedic Surgery, Faculty of Medicine, Saga University, Saga, Japan
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Zhou M, Theologis AA, O’Connell GD. Understanding the etiopathogenesis of lumbar intervertebral disc herniation: From clinical evidence to basic scientific research. JOR Spine 2024; 7:e1289. [PMID: 38222810 PMCID: PMC10782075 DOI: 10.1002/jsp2.1289] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 08/01/2023] [Accepted: 09/20/2023] [Indexed: 01/16/2024] Open
Abstract
Lumbar intervertebral disc herniation, as a leading cause of low back pain, productivity loss, and disability, is a common musculoskeletal disorder that results in significant socioeconomic burdens. Despite extensive clinical and basic scientific research efforts, herniation etiopathogenesis, particularly its initiation and progression, is not well understood. Understanding herniation etiopathogenesis is essential for developing effective preventive measures and therapeutic interventions. Thus, this review seeks to provide a thorough overview of the advances in herniation-oriented research, with a discussion on ongoing challenges and potential future directions for clinical, translational, and basic scientific investigations to facilitate innovative interdisciplinary research aimed at understanding herniation etiopathogenesis. Specifically, risk factors for herniation are identified and summarized, including familial predisposition, obesity, diabetes mellitus, smoking tobacco, selected cardiovascular diseases, disc degeneration, and occupational risks. Basic scientific experimental and computational research that aims to understand the link between excessive mechanical load, catabolic tissue remodeling due to inflammation or insufficient nutrient supply, and herniation, are also reviewed. Potential future directions to address the current challenges in herniation-oriented research are explored by combining known progressive development in existing research techniques with ongoing technological advances. More research on the relationship between occupational risk factors and herniation, as well as the relationship between degeneration and herniation, is needed to develop preventive measures for working-age individuals. Notably, researchers should explore using or modifying existing degeneration animal models to study herniation etiopathogenesis, as such models may allow for a better understanding of how to prevent mild-to-moderately degenerated discs from herniating.
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Affiliation(s)
- Minhao Zhou
- Department of Mechanical EngineeringUniversity of California, Berkeley (UC Berkeley)BerkeleyCaliforniaUSA
| | - Alekos A. Theologis
- Department of Orthopaedic SurgeryUniversity of California, San Francisco (UCSF)San FranciscoCaliforniaUSA
| | - Grace D. O’Connell
- Department of Mechanical EngineeringUniversity of California, Berkeley (UC Berkeley)BerkeleyCaliforniaUSA
- Department of Orthopaedic SurgeryUniversity of California, San Francisco (UCSF)San FranciscoCaliforniaUSA
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Zhang H, Sang D, Zhang B, Ren YN, Wang X, Feng JJ, Du CF, Liu B, Zhu R. Parameter Study on How the Cervical Disc Degeneration Affects the Segmental Instantaneous Centre of Rotation. J Med Biol Eng 2023. [DOI: 10.1007/s40846-023-00779-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
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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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Rahman WU, Jiang W, Zhao F, Li Z, Wang G, Yang G. Biomechanical effect of C5-C6 intervertebral disc degeneration on the human lower cervical spine (C3-C7): a finite element study. Comput Methods Biomech Biomed Engin 2022; 26:820-834. [PMID: 35712878 DOI: 10.1080/10255842.2022.2089026] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The biomechanical effects of intervertebral discs and facet joints degeneration on the cervical spine are essential to understanding the mechanisms of spinal disorders to improve pathological and clinical treatment. In this study, the biomechanical effects of a progressively degenerated C5-C6 segment on the human lower cervical spine are determined by a detailed simulation of intervertebral disc degeneration. A detailed asymmetric three-dimension intact finite element model was developed using computed tomography scan data of the human lower cervical spine (C3-C7). The intact finite element model was then modified at the C5-C6 segment to build three degenerated models, such as mild, moderate, and severe degeneration. The physiological compressive load 73.6 N, and moment 1 Nm were applied at the superior endplate of the vertebra C3, and the inferior endplate of the C7 vertebra was a constraint for all degrees of freedom. Range of motion, maximum von Mises stress in the annulus, intradiscal pressure, and facet joint force of the degenerated models were computed. With progressive degeneration in the C5-C6 segment, the range of motion of degenerated and normal segments decreases in all postures. Intradiscal pressure of the degenerated segment decreases but increases in normal segments of degenerated segment C5-C6, and facet joint forces increase at both degenerated and normal segments. This study emphasizes that the degenerated disc alters the degenerated and normal segments' motion and loading patterns. The abnormal increase in facet joint force in the degenerated models threatened to accelerate the degeneration in the normal segments.
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Affiliation(s)
- Waseem Ur Rahman
- School of Mechanical Engineering, Dalian University of Technology, Dalian, China
| | - Wei Jiang
- School of Mechanical Engineering, Dalian University of Technology, Dalian, China
| | - Fulin Zhao
- School of Mechanical Engineering, Dalian University of Technology, Dalian, China
| | - Zhijun Li
- Department of Orthopedics, Dalian No. 2 People's Hospital, Dalian, China
| | - Guohua Wang
- Department of Orthopedics, Dalian No. 2 People's Hospital, Dalian, China
| | - Guanghui Yang
- School of Mechanical Engineering, Dalian University of Technology, Dalian, China
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Adjacent segments biomechanics following lumbar fusion surgery: a musculoskeletal finite element model 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; 31:1630-1639. [PMID: 35633382 DOI: 10.1007/s00586-022-07262-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 04/18/2022] [Accepted: 05/07/2022] [Indexed: 10/18/2022]
Abstract
PURPOSE This study exploits a novel musculoskeletal finite element (MS-FE) spine model to evaluate the post-fusion (L4-L5) alterations in adjacent segment kinetics. METHODS Unlike the existing MS models with idealized representation of spinal joints, this model predicts stress/strain distributions in all passive tissues while organically coupled to a MS model. This generic (in terms of musculature and material properties) model uses population-based in vivo vertebral sagittal rotations, gravity loads, and an optimization algorithm to calculate muscle forces. Simulations represent individuals with an intact L4-L5, a preoperative severely degenerated L4-L5 (by reducing the disc height by ~ 60% and removing the nucleus incompressibility), and a postoperative fused L4-L5 segment with either a fixed or an altered lumbopelvic rhythm with respect to the intact condition (based on clinical observations). Changes in spine kinematics and back muscle cross-sectional areas (due to intraoperative injuries) are considered based on in vivo data while simulating three activities in upright/flexed postures. RESULTS Postoperative changes in some adjacent segment kinetics were found considerable (i.e., larger than 25%) that depended on the postoperative lumbopelvic kinematics and preoperative L4-L5 disc condition. Postoperative alterations in adjacent disc shear, facet/ligament forces, and annulus stresses/strains were greater (> 25%) than those found in intradiscal pressure and compression (< 25%). Kinetics of the lower (L5-S1) and upper (L3-L4) adjacent segments were altered to different degrees. CONCLUSION Alterations in segmental rotations mainly affected adjacent disc shear forces, facet/ligament forces, and annulus/collagen fibers stresses/strains. An altered lumbopelvic rhythm (increased pelvis rotation) tends to mitigate some of these surgically induced changes.
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Zhou M, Huff R, Abubakr Y, O'Connell G. Torque- and Muscle-Driven Flexion Induce Disparate Risks of In Vitro Herniation: A Multiscale and Multiphasic Structure-Based Finite Element Study. J Biomech Eng 2022; 144:1133336. [PMID: 35079770 DOI: 10.1115/1.4053402] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Indexed: 11/08/2022]
Abstract
The intervertebral disc is a complex structure that experiences multiaxial stresses regularly. Disc failure through herniation is a common cause of lower back pain, which causes reduced mobility and debilitating pain, resulting in heavy socioeconomic burdens. Unfortunately, herniation etiology is not well understood, partially due to challenges in replicating herniation in vitro. Previous studies suggest that flexion elevated risks of herniation. Thus, the objective of this study was to use a multiscale and multiphasic finite element model to evaluate the risk of failure under torque- or muscle-driven flexion. Models were developed to represent torque-driven flexion with the instantaneous center of rotation (ICR) located on the disc, and the more physiologically representative muscle-driven flexion with the ICR located anterior of the disc. Model predictions highlighted disparate disc mechanics regarding bulk deformation, stress-bearing mechanisms, and intradiscal stress-strain distributions. Specifically, failure was predicted to initiate at the bone-disc boundary under torque-driven flexion, which may explain why endplate junction failure, instead of herniation, has been the more common failure mode observed in vitro. By contrast, failure was predicted to initiate in the posterolateral annulus fibrosus under muscle-driven flexion, resulting in consistent herniation. Our findings also suggested that muscle-driven flexion combined with axial compression could be sufficient for provoking herniation in vitro and in silico. In conclusion, this study provided a computational framework for designing in vitro testing protocols that can advance the assessment of disc failure behavior and the performance of engineered disc implants.
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Affiliation(s)
- Minhao Zhou
- University of California, Berkeley, Mechanical Engineering Department, 2162 Etcheverry Hall, #1740, Berkeley, CA 94720-1740
| | - ReeceD Huff
- University of California, Berkeley, Mechanical Engineering Department, 2162 Etcheverry Hall, #1740, Berkeley, CA 94720-1740
| | - Yousuf Abubakr
- University of California, Berkeley, Mechanical Engineering Department, 2162 Etcheverry Hall, #1740, Berkeley, CA 94720-1740
| | - Grace O'Connell
- University of California, Berkeley, Mechanical Engineering Department, University of California, San Francisco, Orthopaedic Surgery Department, 2162 Etcheverry Hall, #1740, Berkeley, CA 94720-1740
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Li N, Cavagnaro MJ, Xiong K, Du X, Shi J. The Multi-Modal Risk Analysis and Medical Prevention of Lumbar Degeneration, Fatigue, and Injury Based on FEM/BMD for Elderly Chinese Women Who Act as Stay-Home Grandchildren Sitters. Front Public Health 2021; 9:700148. [PMID: 34888274 PMCID: PMC8648567 DOI: 10.3389/fpubh.2021.700148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2021] [Accepted: 08/09/2021] [Indexed: 11/17/2022] Open
Abstract
Background: An increasing number of Chinese elderly women stay at home and act as grandchildren sitters. In consequence of the frequent load-bearing, chronic lumbar fatigue probably caused a higher risk of lumbar degeneration, fatigue, and injury which has become one of the most important aging and health problems in China. In this study, a multi-mode lumbar finite element model (FEM) with specific bone mineral density (BMD) were developed and validated for further spine injury prevention and control. Methods: The material properties of lumbar vertebra were modified according to degenerated bone mineral density, and geometry was adjusted based on intervertebral disc height. The motion of lifting children was simulated by a 76 year-old Chinese women's FEM, and the stress distribution was calculated and predicted. Results: The pressure of L5-S intervertebral disc in the bending 3-year-old dummy lifting posture was significantly higher than the same posture without lifting, the maximum effective stress of endplate cartilage in the upright child lifting posture was 1.6 times that of the bending without lifting posture. And the fatigue risk limitation frequency of the upright with dummy posture was predicted with the functional equation of fatigue and stress which was deduced by genetic algorithm, which combined with the effective stress of lumbar vertebrae spongy bone calculated from FEM. Conclusions: The child-lifting motion could increase the risk of lumbar degeneration, fatigue, and injury in elderly women, and they should keep below the frequency limit of the motion of lifting children in their daily life. This study could put forward scientific injury prevention guidance to Chinese elderly women who lift children in daily life frequently.
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Affiliation(s)
- Na Li
- Department of Radiology, The Third Xiangya Hospital, Central South University, Changsha, China
| | - María José Cavagnaro
- College of Medicine-Phoenix, The University of Arizona, Phoenix, AZ, United States
| | - Kun Xiong
- Department of Anatomy and Neurobiology, School of Basic Medical Sciences, Central South University, Changsha, China
| | - Xianping Du
- Department of Mechanical and Aerospace Engineering, Rutgers University, New Brunswick, NJ, United States
| | - Jian Shi
- Department of Spine Surgery, The Third Xiangya Hospital, Central South University, Changsha, China
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Werbner B, Zhou M, McMindes N, Lee A, Lee M, O'Connell GD. Saline-polyethylene glycol blends preserve in vitro annulus fibrosus hydration and mechanics: An experimental and finite-element analysis. J Mech Behav Biomed Mater 2021; 125:104951. [PMID: 34749204 DOI: 10.1016/j.jmbbm.2021.104951] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2021] [Revised: 10/23/2021] [Accepted: 10/27/2021] [Indexed: 01/01/2023]
Abstract
Precise control of tissue water content is essential for ensuring accurate, repeatable, and physiologically relevant measurements of tissue mechanics and biochemical composition. While previous studies have found that saline and polyethylene glycol (PEG) blends were effective at controlling tendon and ligament hydration levels, this work has yet to be extended to the annulus fibrosus (AF). Thus, the first objective of this study was to determine and validate an optimal buffer solution for targeting and maintaining hydration levels of tissue-level AF specimens in vitro. This was accomplished by measuring the transient swelling behavior of bovine AF specimens in phosphate-buffered saline (PBS) and PEG buffers across a wide range of concentrations. Sub-failure, failure, and post-failure mechanics were measured to determine the relationship between changes in tissue hydration and tensile mechanical response. The effect of each buffer solution on tissue composition was also assessed. The second objective of this study was to assess the feasibility and effectiveness of using multi-phasic finite element models to investigate tissue swelling and mechanical responses in different external buffer solutions. A solution containing 6.25%w/v PBS and 6.25%w/v PEG effectively maintained tissue-level AF specimen hydration at fresh-frozen levels after 18 h in solution. Modulus, failure stress, failure strain, and post-failure toughness of specimens soaked in this solution for 18 h closely matched those of fresh-frozen specimens. In contrast, specimens soaked in 0.9%w/v PBS swelled over 100% after 18 h and exhibited significantly diminished sub-failure and failure properties compared to fresh-frozen controls. The increased cross-sectional area with swelling contributed to but was not sufficient to explain the diminished mechanics of PBS-soaked specimens, suggesting additional sub-tissue scale mechanisms. Computational simulations of these specimens generally agreed with experimental results, highlighting the feasibility and importance of including a fluid-phase description when models aim to provide accurate predictions of biological tissue responses. As numerous previous studies suggest that tissue hydration plays a central role in maintaining proper mechanical and biological function, robust methods for controlling hydration levels are essential as the field advances in probing the relationship between tissue hydration, aging, injury, and disease.
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Affiliation(s)
- Benjamin Werbner
- Department of Mechanical Engineering, University of California, Berkeley, USA
| | - Minhao Zhou
- Department of Mechanical Engineering, University of California, Berkeley, USA
| | - Nicole McMindes
- Department of Mechanical Engineering, University of California, Berkeley, USA
| | - Allan Lee
- Department of Bioengineering, University of California, Berkeley, USA
| | - Matthew Lee
- Department of Mechanical Engineering, University of California, Berkeley, USA
| | - Grace D O'Connell
- Department of Mechanical Engineering, University of California, Berkeley, USA; Department of Orthopaedic Surgery, University of California, San Francisco, USA.
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Fan R, Liu J, Liu J. Prediction of the natural frequencies of different degrees of degenerated human lumbar segments L2-L3 using dynamic finite element analysis. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 209:106352. [PMID: 34419755 DOI: 10.1016/j.cmpb.2021.106352] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Accepted: 08/05/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND AND OBJECTIVE Chronic exposure to resonant environment may cause more serious injuries to human lumbar spine than other vibrations. On the condition that the natural frequency of human lumbar spine is known, excitation frequency from an external vibration source can be optimized to keep away from the natural frequency and thus avoid lumbar resonance. Therefore, this study aimed to present an approach to predict the natural frequency of the human lumbar spine. METHODS Four poroelastic finite element models of human L2-L3 spinal motion segments with different degrees of degeneration were established. Dynamic finite element analyses of these models during 1 h of vibration were then conducted. The mechanical parameters of these models under vibrations at different excitation frequencies were predicted. The excitation frequencies that resulted in the greatest changes in the lumbar mechanical parameters were identified as the natural frequencies of the established L2-L3 spinal motion segments. RESULTS Simulation results showed that the natural frequencies of the healthy and mildly degenerated L2-L3 spinal motion segments, moderately degenerated L2-L3 spinal motion segments, and seriously degenerated L2-L3 spinal motion segments were in the range of 5-7, 3-5, and 1-3 Hz, respectively. CONCLUSIONS The predicted results indicated that the natural frequencies of the human L2-L3 spinal motion segments gradually decreased with the severity of degeneration. These phenomena may be related to changes in the lumbar structures and materials because of degeneration. This study provided a feasible method to predict the lumbar natural frequencies for different populations, which may be helpful in optimizing external vibration sources to avoid lumbar resonance.
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Affiliation(s)
- Ruoxun Fan
- Department of Automotive Engineering, Jilin Institute of Chemical Technology, Jilin 132022, China.
| | - Jie Liu
- Department of Automotive Engineering, Jilin Institute of Chemical Technology, Jilin 132022, China
| | - Jun Liu
- Second Hospital of Jilin University, Jilin University, Changchun 130025, China
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Wang W, Zhou C, Guo R, Cha T, Li G. Prediction of biomechanical responses of human lumbar discs - a stochastic finite element model analysis. Comput Methods Biomech Biomed Engin 2021; 24:1730-1741. [PMID: 34121532 DOI: 10.1080/10255842.2021.1914023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Accurate biomechanical investigation of human intervertebral discs (IVDs) is difficult because of their complicated structural and material features. AIM To investigate probabilistic distributions of the biomechanical responses of the IVD by considering varying nonlinear structural and material properties using a stochastic finite element (FE) model. METHODS A FE model of a L3-4 disc was reconstructed, including the nucleus pulposus (NP), annular matrix and fibers. A Monte Carlo method was used to randomly generate 500 sets of the nonlinear material properties and fiber orientations of the disc that were implemented into the FE model. The FE model was analyzed under seven loading conditions: a 500 N compressive force, a 7.5Nm moment simulating flexion, extension, left-right lateral bending, and left-right axial rotation, respectively. The distributions of the ranges of motion (ROMs), intradiscal pressures (IDP), fiber stresses and matrix strains of the disc were analyzed. RESULTS Under the compressive load, the displacement varied between 0.29 mm and 0.76 mm. Under the 7.5Nm moment, the ROMs varied between 3.0° and 6.0° in primary rotations. The IDPs varied within 0.3 MPa under all the loading conditions. The maximal fiber stress (3.22 ± 0.64 MPa) and matrix strain (0.27 ± 0.12%) were observed under the flexion and extension moments, respectively. CONCLUSION The IVD biomechanics could be dramatically affected by the structural and material parameters used to construct the FE model. The stochastic FE model that includes the probabilistic distributions of the structural and material parameters provides a useful approach to analyze the statistical ranges of the biomechanical responses of the IVDs.
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Affiliation(s)
- Wei Wang
- Orthopaedic Bioengineering Research Center, Department of Orthopaedic Surgery, Newton-Wellesley Hospital, Newton, MA, USA.,Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.,School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Chaochao Zhou
- Orthopaedic Bioengineering Research Center, Department of Orthopaedic Surgery, Newton-Wellesley Hospital, Newton, MA, USA.,Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Runsheng Guo
- Orthopaedic Bioengineering Research Center, Department of Orthopaedic Surgery, Newton-Wellesley Hospital, Newton, MA, USA.,Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.,Department of Orthopaedics, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Thomas Cha
- Orthopaedic Bioengineering Research Center, Department of Orthopaedic Surgery, Newton-Wellesley Hospital, Newton, MA, USA.,Department of Orthopaedic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Guoan Li
- Orthopaedic Bioengineering Research Center, Department of Orthopaedic Surgery, Newton-Wellesley Hospital, Newton, MA, USA
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12
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Zhou M, Lim S, O’Connell GD. A Robust Multiscale and Multiphasic Structure-Based Modeling Framework for the Intervertebral Disc. Front Bioeng Biotechnol 2021; 9:685799. [PMID: 34164388 PMCID: PMC8215504 DOI: 10.3389/fbioe.2021.685799] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 05/10/2021] [Indexed: 12/11/2022] Open
Abstract
A comprehensive understanding of multiscale and multiphasic intervertebral disc mechanics is crucial for designing advanced tissue engineered structures aiming to recapitulate native tissue behavior. The bovine caudal disc is a commonly used human disc analog due to its availability, large disc height and area, and similarities in biochemical and mechanical properties to the human disc. Because of challenges in directly measuring subtissue-level mechanics, such as in situ fiber mechanics, finite element models have been widely employed in spinal biomechanics research. However, many previous models use homogenization theory and describe each model element as a homogenized combination of fibers and the extrafibrillar matrix while ignoring the role of water content or osmotic behavior. Thus, these models are limited in their ability in investigating subtissue-level mechanics and stress-bearing mechanisms through fluid pressure. The objective of this study was to develop and validate a structure-based bovine caudal disc model, and to evaluate multiscale and multiphasic intervertebral disc mechanics under different loading conditions and with degeneration. The structure-based model was developed based on native disc structure, where fibers and matrix in the annulus fibrosus were described as distinct materials occupying separate volumes. Model parameters were directly obtained from experimental studies without calibration. Under the multiscale validation framework, the model was validated across the joint-, tissue-, and subtissue-levels. Our model accurately predicted multiscale disc responses for 15 of 16 cases, emphasizing the accuracy of the model, as well as the effectiveness and robustness of the multiscale structure-based modeling-validation framework. The model also demonstrated the rim as a weak link for disc failure, highlighting the importance of keeping the cartilage endplate intact when evaluating disc failure mechanisms in vitro. Importantly, results from this study elucidated important fluid-based load-bearing mechanisms and fiber-matrix interactions that are important for understanding disease progression and regeneration in intervertebral discs. In conclusion, the methods presented in this study can be used in conjunction with experimental work to simultaneously investigate disc joint-, tissue-, and subtissue-level mechanics with degeneration, disease, and injury.
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Affiliation(s)
- Minhao Zhou
- Berkeley Biomechanics Laboratory, Department of Mechanical Engineering, University of California, Berkeley, Berkeley, CA, United States
| | - Shiyin Lim
- Berkeley Biomechanics Laboratory, Department of Mechanical Engineering, University of California, Berkeley, Berkeley, CA, United States
| | - Grace D. O’Connell
- Berkeley Biomechanics Laboratory, Department of Mechanical Engineering, University of California, Berkeley, Berkeley, CA, United States
- Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, United States
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The effect of cervical intervertebral disc degeneration on the motion path of instantaneous center of rotation at degenerated and adjacent segments: A finite element analysis. Comput Biol Med 2021; 134:104426. [PMID: 33979732 DOI: 10.1016/j.compbiomed.2021.104426] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 04/20/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND The motion path of instantaneous center of rotation (ICR) is a crucial kinematic parameter to dynamically characterize cervical spine intervertebral patterns of motion; however, few studies have evaluated the effect of cervical disc degeneration (CDD) on ICR motion path. The purpose of this study was to investigate the effect of CDD on the ICR motion path of degenerated and adjacent segments. METHOD A validated nonlinear three-dimensional finite element (FE) model of a healthy adult cervical spine was used. Progressive degeneration was simulated with six FE models by modifying intervertebral disc height and material properties, anterior osteophyte size, and degree of endplate sclerosis at the C5-C6 level. All models were subjected to a pure moment of 1 Nm and a compressive follower load of 73.6 N to simulate physical motion. ICR motion paths were compared among different models. RESULTS The normal FE model results were consistent with those of previous studies. In degenerative models, average ICR motion paths shifted significantly anterior at the degenerated segment (β = 0.27 mm; 95% CI: 0.22, 0.32) and posterior at the proximal adjacent segment (β = -0.09 mm; 95% CI: -0.15, -0.02) than those of the normal model. CONCLUSION CDD significantly affected ICR motion paths at the degenerated and proximal adjacent segments. The changes at adjacent segments may be a result of compensatory mechanisms to maintain the balance of the cervical spine. Surgical treatment planning should take into account the restoration of ICR motion path to normal. These findings could provide a basis for prosthesis design and clinical practice.
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Du CF, Cai XY, Gui W, Sun MS, Liu ZX, Liu CJ, Zhang CQ, Huang YP. Does oblique lumbar interbody fusion promote adjacent degeneration in degenerative disc disease: A finite element analysis. Comput Biol Med 2020; 128:104122. [PMID: 33248365 DOI: 10.1016/j.compbiomed.2020.104122] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 11/14/2020] [Accepted: 11/14/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND The number of oblique lumbar interbody fusion (OLIF) procedures has continued to rise over recent years. Adjacent segment degeneration (ASD) is a common complication following vertebral body fusion. Although the precise mechanism remains uncertain, ASD has gradually become more common in OLIF. Therefore, the present study analyzed the association between disc degeneration and OLIF to explore whether adjacent degeneration was promoted by OLIF in degenerative disc disease. METHODS A three-dimensional nonlinear finite element (FE) model of the L3-S1 lumbar spine was developed and validated. Three lumbar spine degeneration models with different degrees of degeneration (mild, moderate and severe) and a model of OLIF surgery were constructed at the L4-L5 level. When subjected to a follower compressive load (500 N), hybrid moment loading was applied to all models of the lumbar spine and the range of motion (ROM), intradiscal pressure (IDP), facet joint force (FJF), average mises stress in the annulus (AMSA), average tresca stress in the annulus (ATSA) and average endplate stress (AES) were measured. RESULTS Compared with the healthy lumbar spine model, the ROM, IDP, FJF, AMSA, ATSA and AES of the segments adjacent to the degenerated segment increased in each posture as the degree of disc degeneration increased. In different directions of motion, the ROM, IDP, FJF, AMSA, ATSA and AES in the OLIF model in the L3-L4 and L5-S1 segments were higher than those of the healthy model and each degenerated model. Compared with the healthy model, the largest relative increase in biomechanical parameters above (ROM, IDP, FJF, AMSA, ATSA or AES) was observed in the L3-L4 segment in the OLIF model, of 77.13%, 32.63%, 237.19%, 45.36%, 110.92% and 80.28%, respectively. In the L5-S1 segment the corresponding values were 68.88%, 36.12%, 147.24%, 46.00%, 45.88% and 51.29%, respectively. CONCLUSIONS Both degenerated discs and OLIF surgery modified the pattern of motion and load distribution of adjacent segments (L3-L4 and L5-S1 segments). The increases in the biomechanical parameters of segments adjacent to the surgical segment in the OLIF model were more apparent than those of the degenerated models. In summary, OLIF risked accelerating the degeneration of segments adjacent to those of a surgical segment.
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Affiliation(s)
- Cheng-Fei Du
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, 300384, China; National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, Tianjin University of Technology, Tianjin, 300384, China
| | - Xin-Yi Cai
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, 300384, China; National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, Tianjin University of Technology, Tianjin, 300384, China
| | - Wu Gui
- Department of Spine Surgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350000, Fujian, China
| | - Meng-Si Sun
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, 300384, China; National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, Tianjin University of Technology, Tianjin, 300384, China
| | - Zi-Xuan Liu
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, 300384, China; National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, Tianjin University of Technology, Tianjin, 300384, China
| | - Chun-Jie Liu
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, 300384, China; National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, Tianjin University of Technology, Tianjin, 300384, China
| | - Chun-Qiu Zhang
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, 300384, China; National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, Tianjin University of Technology, Tianjin, 300384, China
| | - Yun-Peng Huang
- Department of Spine Surgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, 350000, Fujian, China.
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15
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Fan R, Liu J, Liu J. Finite element investigation on the dynamic mechanical properties of low-frequency vibrations on human L2-L3 spinal motion segments with different degrees of degeneration. Med Biol Eng Comput 2020; 58:3003-3016. [PMID: 33064234 DOI: 10.1007/s11517-020-02263-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 08/29/2020] [Indexed: 11/26/2022]
Abstract
Exposure to low-frequency vibration is harmful to human lumbar health. However, the dynamic mechanical properties of lumbar spines with varying degrees of degeneration during time-dependent vibration remain incompletely understood. In this study, four poroelastic finite element models of human L2-L3 spinal motion segments, including the non-degeneration and the mild, moderate, and serious degeneration, were established. One-hour low-frequency vibrations with different frequencies were applied. Then, the dynamic mechanical properties of different degenerated lumbar models under the same vibration and the same lumbar model under vibrations at different frequencies were investigated. The results indicated and implied that the negative influences of 1-h vibration on the dynamic mechanical properties of the non-degenerated and mildly degenerated models were similar, but became obvious for the moderately and seriously degenerated models with time. Therefore, the damage caused by low-frequency vibration on the degenerated spinal motion segments was more serious compared with that on the healthy one. Meanwhile, the dynamic mechanical properties of the same lumbar model under vibrations at different frequencies expressed the negligible differences when the vibration frequency was not close to the lumbar natural frequency. Thus, the effects of the 1-h vibrations at different frequencies on one spinal motion segment were similar. Vibration frequency sensitivity analysis on the dynamic characteristics of human L2-L3 spinal motion segments with different degrees of degeneration.
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Affiliation(s)
- Ruoxun Fan
- Department of Automotive Engineering, Jilin Institute of Chemical Technology, Jilin, 132022, China.
| | - Jie Liu
- Department of Automotive Engineering, Jilin Institute of Chemical Technology, Jilin, 132022, China
| | - Jun Liu
- Second Hospital of Jilin University, Jilin University, Changchun, 130025, China
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16
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Ni W, Zhang F, Zheng L, Wang L, Liang Y, Ding Y, Yik JHN, Haudenschild DR, Fan S, Hu Z. Cyclin-Dependent Kinase 9 (CDK9) Inhibitor Atuveciclib Suppresses Intervertebral Disk Degeneration via the Inhibition of the NF-κB Signaling Pathway. Front Cell Dev Biol 2020; 8:579658. [PMID: 33015073 PMCID: PMC7511812 DOI: 10.3389/fcell.2020.579658] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 08/20/2020] [Indexed: 12/30/2022] Open
Abstract
Intervertebral disk degeneration (IVDD) is a spinal disk condition caused by an inflammatory response induced by various proinflammatory cytokines, such as interleukin (IL)-1β and tumor necrosis factor (TNF)-α. cyclin-dependent kinase 9 (CDK9) is a transcriptional regulator and potential therapeutic target for many diseases, especially in regulating the activation of primary inflammatory response genes. Our study investigated a highly selective CDK9 inhibitor, atuveciclib, which protects nucleus pulposus (NP) cells from proinflammatory stimuli-induced catabolism. The effects of CDK9 inhibition were determined in human and rat NP cells treated with IL-1β in the presence or absence of atuveciclib or small interfering RNA target CDK9. Inhibition of CDK9 led to the attenuation of inflammatory response. In addition, rat intervertebral disk (IVD) explants were used to determine the role of CDK9 inhibition in extracellular matrix degradation. The rat IVDD model also proved that CDK9 inhibition attenuated IVDD, as validated using magnetic resonance imaging and immunohistochemistry. Taken together, CDK9 is a potential therapeutic target to prevent IVDD.
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Affiliation(s)
- Weiyu Ni
- Department of Orthopaedic Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Musculoskeletal System Degeneration and Regeneration Translational Research, Zhejiang University School of Medicine, Hangzhou, China
| | - Feizhou Zhang
- The Children's Hospital of Zhejiang University School of Medicine, Hangzhou, China
| | - Lin Zheng
- Department of Orthopaedic Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Musculoskeletal System Degeneration and Regeneration Translational Research, Zhejiang University School of Medicine, Hangzhou, China
| | - Lili Wang
- School of Statistics and Mathematics, Zhejiang Gongshang University, Hangzhou, China
| | - Yi Liang
- Department of Orthopaedic Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Musculoskeletal System Degeneration and Regeneration Translational Research, Zhejiang University School of Medicine, Hangzhou, China
| | - Yuhong Ding
- Department of Orthopaedic Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Musculoskeletal System Degeneration and Regeneration Translational Research, Zhejiang University School of Medicine, Hangzhou, China
| | - Jasper H N Yik
- Department of Orthopaedic Surgery, UC Davis Medical Center, Sacramento, CA, United States
| | - Dominik R Haudenschild
- Department of Orthopaedic Surgery, UC Davis Medical Center, Sacramento, CA, United States
| | - Shunwu Fan
- Department of Orthopaedic Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Musculoskeletal System Degeneration and Regeneration Translational Research, Zhejiang University School of Medicine, Hangzhou, China
| | - Ziang Hu
- Department of Orthopaedic Surgery, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China.,Key Laboratory of Musculoskeletal System Degeneration and Regeneration Translational Research, Zhejiang University School of Medicine, Hangzhou, China
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17
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Hassan CR, Lee W, Komatsu DE, Qin YX. Evaluation of nucleus pulposus fluid velocity and pressure alteration induced by cartilage endplate sclerosis using a poro-elastic finite element analysis. Biomech Model Mechanobiol 2020; 20:281-291. [PMID: 32949306 DOI: 10.1007/s10237-020-01383-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Accepted: 09/01/2020] [Indexed: 11/25/2022]
Abstract
The nucleus pulposus (NP) in the intervertebral disk (IVD) depends on diffusive fluid transport for nutrients through the cartilage endplate (CEP). Disruption in fluid exchange of the NP is considered a cause of IVD degeneration. Furthermore, CEP calcification and sclerosis are hypothesized to restrict fluid flow between the NP and CEP by decreasing permeability and porosity of the CEP matrix. We performed a finite element analysis of an L3-L4 lumbar functional spine unit with poro-elastic constitutive equations. The aim of the study was to predict changes in the solid and fluid parameters of the IVD and CEP under structural changes in CEP. A compressive load of 500 N was applied followed by a 10 Nm moment in extension, flexion, lateral bending, and axial rotation to the L3-L4 model with fully saturated IVD, CEP, and cancellous bone. A healthy case of L3-L4 physiology was then compared to two cases of CEP sclerosis: a calcified cartilage endplate and a fluid constricted sclerotic cartilage endplate. Predicted NP fluid velocity increased for the calcified CEP and decreased for the calcified + less permeable CEP. Decreased NP fluid velocity was prominent in the axial direction through the CEP due to a less permeable path available for fluid flux. Fluid pressure and maximum principal stress in the NP were predicted to increase in both cases of CEP sclerosis compared to the healthy case. The porous medium predictions of this analysis agree with the hypothesis that CEP sclerosis decreases fluid flow out of the NP, builds up fluid pressure in the NP, and increases the stress concentrations in the NP solid matrix.
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Affiliation(s)
- Chaudhry Raza Hassan
- Department of Biomedical Engineering, Stony Brook University, 215 Bioengineering Building, Stony Brook, NY, 11794, USA
| | - Wonsae Lee
- Department of Biomedical Engineering, Stony Brook University, 215 Bioengineering Building, Stony Brook, NY, 11794, USA
| | - David Edward Komatsu
- Department of Orthopaedics, School of Medicine, Stony Brook University, Stony Brook, NY, USA
| | - Yi-Xian Qin
- Department of Biomedical Engineering, Stony Brook University, 215 Bioengineering Building, Stony Brook, NY, 11794, USA.
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18
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Cai XY, Sun MS, Huang YP, Liu ZX, Liu CJ, Du CF, Yang Q. Biomechanical Effect of L 4 -L 5 Intervertebral Disc Degeneration on the Lower Lumbar Spine: A Finite Element Study. Orthop Surg 2020; 12:917-930. [PMID: 32476282 PMCID: PMC7307239 DOI: 10.1111/os.12703] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/03/2020] [Accepted: 04/22/2020] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVE To ascertain the biomechanical effects of a degenerated L4 -L5 segment on the lower lumbar spine through a comprehensive simulation of disc degeneration. METHODS A three-dimensional nonlinear finite element model of a normal L3 -S1 lumbar spine was constructed and validated. This normal model was then modified such that three degenerated models with different degrees of degeneration (mild, moderate, or severe) at the L4 -L5 level were constructed. While experiencing a follower compressive load (500 N), hybrid moment loads were applied to all models to determine range of motion (ROM), intradiscal pressure (IDP), maximum von Mises stress in the annulus, maximum shear stress in the annulus, and facet joint force. RESULTS As the degree of disc degeneration increased, the ROM of the L4 -L5 degenerated segment declined dramatically in all postures (flexion: 5.79°-1.91°; extension: 5.53°-2.62°; right lateral bending: 4.47°-1.46°; left lateral bending: 4.86°-1.61°; right axial rotation: 2.69°-0.74°; left axial rotation: 2.69°-0.74°), while the ROM in adjacent segments increased (1.88°-8.19°). The largest percent decrease in motion of the L4 -L5 segment due to disc degeneration was in right axial rotation (75%), left axial rotation (69%), flexion (67%), right lateral bending (67%), left lateral bending right (67%), and extension (53%). The change in the trend of the IDP was the same as that of the ROM. Specifically, the IDP decreased (flexion: 0.592-0.09 MPa; extension: 0.678-0.334 MPa; right lateral bending: 0.498-0.205 MPa; left lateral bending: 0.523-0.272 MPa; right axial rotation: 0.535-0.246 MPa; left axial rotation: 0.53-0.266 MPa) in the L4 -L5 segment, while the IDP in adjacent segments increased (0.511-0.789 MPa). The maximum von Mises stress and maximum shear stress of the annulus in whole lumbar spine segments increased (L4 -L5 segment: 0.413-2.626 MPa and 0.412-2.783 MPa, respectively; adjacent segment of L4 -L5 : 0.356-1.493 MPa and 0.359-1.718 MPa, respectively) as degeneration of the disc progressively increased. There was no apparent regularity in facet joint force in the degenerated segment as the degree of disc degeneration increased. Nevertheless, facet joint forces in adjacent healthy segments increased as the degree of disc degeneration increased (extension: 49.7-295.3 N; lateral bending: 3.5-171.2 N; axial rotation: 140.2-258.8 N). CONCLUSION Degenerated discs caused changes in the motion and loading pattern of the degenerated segments and adjacent normal segments. The abnormal load and motion in the degenerated models risked accelerating degeneration in the adjacent normal segments. In addition, accurate simulation of degenerated facet joints is essential for predicting changes in facet joint loads following disc degeneration.
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Affiliation(s)
- Xin-Yi Cai
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, China.,National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, Tianjin University of Technology, Tianjin, China
| | - Meng-Si Sun
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, China.,National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, Tianjin University of Technology, Tianjin, China
| | - Yun-Peng Huang
- Department of Spine Surgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian, China
| | - Zi-Xuan Liu
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, China.,National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, Tianjin University of Technology, Tianjin, China
| | - Chun-Jie Liu
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, China.,National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, Tianjin University of Technology, Tianjin, China
| | - Cheng-Fei Du
- Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control, School of Mechanical Engineering, Tianjin University of Technology, Tianjin, China.,National Demonstration Center for Experimental Mechanical and Electrical Engineering Education, Tianjin University of Technology, Tianjin, China
| | - Qiang Yang
- Department of Spine Surgery, Tianjin Hospital, Tianjin, China
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19
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Internal load-sharing in the human passive lumbar spine: Review of in vitro and finite element model studies. J Biomech 2020; 102:109441. [DOI: 10.1016/j.jbiomech.2019.109441] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 10/13/2019] [Accepted: 10/14/2019] [Indexed: 01/08/2023]
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20
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Cai XY, Sang D, Yuchi CX, Cui W, Zhang C, Du CF, Liu B. Using finite element analysis to determine effects of the motion loading method on facet joint forces after cervical disc degeneration. Comput Biol Med 2020; 116:103519. [DOI: 10.1016/j.compbiomed.2019.103519] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 10/23/2019] [Accepted: 10/24/2019] [Indexed: 01/19/2023]
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21
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Loepfe M, Duss A, Zafeiropoulou KA, Björgvinsdóttir O, D'Este M, Eglin D, Fortunato G, Klasen J, Ferguson SJ, Wuertz-Kozak K, Krupkova O. Electrospray-Based Microencapsulation of Epigallocatechin 3-Gallate for Local Delivery into the Intervertebral Disc. Pharmaceutics 2019; 11:E435. [PMID: 31480533 PMCID: PMC6781552 DOI: 10.3390/pharmaceutics11090435] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 08/16/2019] [Accepted: 08/20/2019] [Indexed: 01/17/2023] Open
Abstract
Locally delivered anti-inflammatory compounds can restore the homeostasis of the degenerated intervertebral disc (IVD). With beneficial effects on IVD cells, epigallocatechin 3-gallate (EGCG) is a promising therapeutic candidate. However, EGCG is prone to rapid degradation and/or depletion. Therefore, the purpose of this study was to develop a method for controlled EGCG delivery in the degenerated IVD. Primary IVD cells were isolated from human donors undergoing IVD surgeries. EGCG was encapsulated into microparticles by electrospraying of glutaraldehyde-crosslinked gelatin. The resulting particles were characterized in terms of cytocompatibility and anti-inflammatory activity, and combined with a thermoresponsive carrier to produce an injectable EGCG delivery system. Subsequently, electrospraying was scaled up using the industrial NANOSPIDER™ technology. The produced EGCG microparticles reduced the expression of inflammatory (IL-6, IL-8, COX-2) and catabolic (MMP1, MMP3, MMP13) mediators in pro-inflammatory 3D cell cultures. Combining the EGCG microparticles with the carrier showed a trend towards modulating EGCG activity/release. Electrospray upscaling was achieved, leading to particles with homogenous spherical morphologies. In conclusion, electrospray-based encapsulation of EGCG resulted in cytocompatible microparticles that preserved the activity of EGCG and showed the potential to control EGCG release, thus favoring IVD health by downregulating local inflammation. Future studies will focus on further exploring the biological activity of the developed delivery system for potential clinical use.
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Affiliation(s)
- Moira Loepfe
- Institute for Biomechanics, ETH Zurich, Hönggerbergring 64, 8093 Zurich, Switzerland
| | - Anja Duss
- Institute for Biomechanics, ETH Zurich, Hönggerbergring 64, 8093 Zurich, Switzerland
| | | | - Oddny Björgvinsdóttir
- Institute for Biomechanics, ETH Zurich, Hönggerbergring 64, 8093 Zurich, Switzerland
| | - Matteo D'Este
- AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland
| | - David Eglin
- AO Research Institute Davos, Clavadelerstrasse 8, 7270 Davos, Switzerland
| | - Giuseppino Fortunato
- Empa, Swiss Federal Laboratories for Materials Science and Technology, Laboratory for Biomimetic Membranes and Textiles, Lerchenfeldstr. 5, 9014 St. Gallen, Switzerland
| | - Juergen Klasen
- Clinic Prodorso, Walchestrasse 15, 8006 Zurich, Switzerland
| | - Stephen J Ferguson
- Institute for Biomechanics, ETH Zurich, Hönggerbergring 64, 8093 Zurich, Switzerland
| | - Karin Wuertz-Kozak
- Institute for Biomechanics, ETH Zurich, Hönggerbergring 64, 8093 Zurich, Switzerland
- Schön Clinic Munich Harlaching, Spine Center, Academic Teaching Hospital and Spine Research Institute of the Paracelsus Medical University Salzburg (AU), Harlachinger Str. 51, 81547 Munich, Germany
- Department of Health Sciences, University of Potsdam, Am Neuen Palais 10, 14469 Potsdam, Germany
| | - Olga Krupkova
- Institute for Biomechanics, ETH Zurich, Hönggerbergring 64, 8093 Zurich, Switzerland.
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22
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Hu BW, Lv X, Chen SF, Shao ZW. Application of Finite Element Analysis for Investigation of Intervertebral Disc Degeneration: from Laboratory to Clinic. Curr Med Sci 2019; 39:7-15. [PMID: 30868485 DOI: 10.1007/s11596-019-1993-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 09/06/2018] [Indexed: 01/06/2023]
Abstract
Due to the ethical concern and inability to detect inner stress distributions of intervertebral disc (IVD), traditional methods for investigation of intervertebral disc degeneration (IVDD) have significant limitations. Many researchers have demonstrated that finite element analysis (FEA) is an effective tool for the research of IVDD. However, the specific application of FEA for investigation of IVDD has not been systematically elucidated before. In the present review, we summarize the current finite element models (FEM) used for the investigation of IVDD, including the poroelastic nonlinear FEM, diffusive-reactive theory model and cell-activity coupled mechano-electrochemical theory model. We further elaborate the use of FEA for the research of IVDD pathogenesis especially for nutrition and biomechanics associated etiology, and the biological, biomechanical and clinical influences of IVDD. In addition, the application of FEA for evaluation and exploration of various treatments for IVDD is also elucidated. We conclude that FEA is an excellent technique for research of IVDD, which could be used to explore the etiology, biology and biomechanics of IVDD. In the future, FEA may help us to achieve the goal of individualized precision therapy.
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Affiliation(s)
- Bin-Wu Hu
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Xiao Lv
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China
| | - Song-Feng Chen
- Department of Orthopaedic Surgery, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Zeng-Wu Shao
- Department of Orthopaedics, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430022, China.
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Presentation of an Approach on Determination of the Natural Frequency of Human Lumbar Spine Using Dynamic Finite Element Analysis. Appl Bionics Biomech 2019; 2019:5473891. [PMID: 30719072 PMCID: PMC6334357 DOI: 10.1155/2019/5473891] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 10/25/2018] [Accepted: 11/06/2018] [Indexed: 11/18/2022] Open
Abstract
Occurring resonance may negatively affect the health of the human lumbar spine. Hence, vibration generated in working and living environments should be optimized to avoid resonance when identifying the natural frequency of the human lumbar spine. The range of the natural frequency of the human lumbar spine has been investigated, but its specific numerical value has not been determined yet. This study aimed at presenting an approach based on resonance for predicting the specific numerical value of the natural frequency of the human lumbar spine. The changes in the numerical fluctuation amplitudes and the cycles of lumbar mechanical parameters during resonance are greater than those during nonresonant vibration. Given that the range of the natural frequency has been identified, vibrations at different excitation frequencies within this range can be applied in a human lumbar finite element model for dynamic finite element analysis. When the excitation frequency is close to the natural frequency, resonance occurs, causing great changes in the numerical fluctuation amplitudes and the cycles of lumbar mechanical parameters. Therefore, the natural frequency of the lumbar finite element model could be back-calculated. Results showed that the natural frequency of the established model was 3.5 Hz. Meanwhile, the closer the excitation frequency was to the natural frequency, the greater the changes in the numerical fluctuation amplitudes and cycles in the parameters would be. This study presented an approach for predicting the specific numerical value of the natural frequency of the human lumbar spine. Identifying the natural frequency assists in finding preventive measures for lumbar injury caused by vibration and in designing the vibration source in working and living environments to avoid approximating to the natural frequency of the human lumbar spine.
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Finite Element Investigation of the Effects of the Low-Frequency Vibration Generated by Vehicle Driving on the Human Lumbar Mechanical Properties. BIOMED RESEARCH INTERNATIONAL 2018; 2018:7962414. [PMID: 30364013 PMCID: PMC6186348 DOI: 10.1155/2018/7962414] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 09/05/2018] [Accepted: 09/16/2018] [Indexed: 11/17/2022]
Abstract
Long-term exposure to low-frequency vibration generated by vehicle driving impairs human lumbar spine health. However, few studies have investigated how low-frequency vibration affects human lumbar mechanical properties. This study established a poroelastic finite element model of human lumbar spinal segments L2–L3 to perform time-dependent vibrational simulation analysis and investigated the effects of different vibrational frequencies generated by normal vehicle driving on the lumbar mechanical properties in one hour. Analysis results showed that vibrational load caused more injury to lumbar health than static load, and vibration at the resonant frequency generated the most serious injury. The axial effective stress and the radial displacement in the intervertebral disc, as well as the fluid loss in the nucleus pulposus, increased, whereas the pore pressure in the nucleus pulposus decreased with increased vibrational frequency under the same vibrational time, which may aggravate the injury degree of human lumbar spine. Therefore, long-term driving on a well-paved road also induces negative effects on human lumbar spine health. When driving on a nonpaved road or operating engineering machinery under poor navigating condition, the auto seat transmits relatively high vibrational frequency, which is highly detrimental to the lumbar spine health of a driver.
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Bashkuev M, Reitmaier S, Schmidt H. Effect of disc degeneration on the mechanical behavior of the human lumbar spine: a probabilistic finite element study. Spine J 2018; 18:1910-1920. [PMID: 29886164 DOI: 10.1016/j.spinee.2018.05.046] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 05/28/2018] [Accepted: 05/31/2018] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Intervertebral disc degeneration has been subject to numerous in vivo and in vitro investigations and numerical studies during recent decades, reporting partially contradictory findings. However, most of the previous studies were limited in the number of specimens investigated and, therefore, could not consider the vast variety of the specimen geometries, which are likely to strongly influence the mechanical behavior of the spine. PURPOSE To complement the understanding of the mechanical consequences of disc degeneration, whereas considering natural variations in the major spinal geometrical parameters. DESIGN/SETTING A probabilistic finite element study. METHODS A parametric finite element model of a human L4-L5 motion segment considering 40 geometrical parameters was developed. One thousand individual geometries comprising four degeneration grades were generated in a probabilistic manner, and the influence of the severity of disc degeneration on the mechanical response of the motion segment to different loading conditions was statistically evaluated. RESULTS Variations in the individual structural parameters resulted in marked variations in all evaluated parameters within each degeneration grade. Nevertheless, the effect of degeneration in almost all evaluated response values was statistically significant. With degeneration, the intradiscal pressure progressively decreased. At the same time, the facet loads increased and the ligament tension was reduced. The initially nonlinear load-deformation relationships became linear whereas the segment stiffness increased. CONCLUSIONS Results indicate significant stiffening of the motion segment with progressing degeneration and gradually increasing loading of the facets from nondegenerated to moderately degenerated conditions along with a significant reduction of the ligament tension in flexion.
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Affiliation(s)
- Maxim Bashkuev
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Julius Wolff Institut, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Sandra Reitmaier
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Julius Wolff Institut, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Hendrik Schmidt
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Julius Wolff Institut, Augustenburger Platz 1, 13353 Berlin, Germany.
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Li L, Shen T, Li YK. A Finite Element Analysis of Stress Distribution and Disk Displacement in Response to Lumbar Rotation Manipulation in the Sitting and Side-Lying Positions. J Manipulative Physiol Ther 2018; 40:580-586. [PMID: 29187309 DOI: 10.1016/j.jmpt.2017.07.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 06/30/2017] [Accepted: 07/20/2017] [Indexed: 11/27/2022]
Abstract
OBJECTIVE This study aimed to investigate stress distribution and disk displacement in healthy and degenerated intervertebral disks during simulated lumbar rotation manipulation (LRM) in the sitting and side-lying positions. METHODS Three-dimensional (3D) finite element models of healthy, mildly degenerated and moderately degenerated L4/5 spinal units were reconstructed. Lumbar rotation manipulation in the sitting and side-lying positions were simulated, and alterations in stress distribution and disk displacement in the lumbar disks were observed. RESULTS The application of LRM in the sitting or side-lying position resulted in a similar stress distribution in healthy, mildly degenerated, and moderately degenerated disks. Stress was concentrated at the anterior right side of the annulus. In all disks, intradiskal pressure (IDP) and maximum von Mises stress were higher during LRM in the sitting position than during LRM in the side-lying position. During these manipulations, Intradiskal pressure and stress in the annulus of moderately degenerated disks were higher than in mildly degenerated disks. Displacement was most obvious in healthy disks. CONCLUSIONS Mildly and moderately degenerated lumbar disks were subject to higher stress during LRM in the sitting position than during LRM in the side-lying position. Intradiskal pressure and the maximum von Mises stress in the annulus of moderately degenerated disks increased, suggesting the need for caution when treating patients with moderately compromised disks. Although our results are in accordance with previously published data, they are simulated and preliminary and do not necessarily replicate the clinical condition.
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Affiliation(s)
- Li Li
- School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, Guangdong Province, China; Department of Rehabilitation Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong Province, China.
| | - Tong Shen
- Department of Rehabilitation Medicine, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong Province, China
| | - Yi-Kai Li
- School of Traditional Chinese Medicine, Southern Medical University, Guangzhou, Guangdong Province, China
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Volkheimer D, Galbusera F, Liebsch C, Schlegel S, Rohlmann F, Kleiner S, Wilke HJ. Is intervertebral disc degeneration related to segmental instability? An evaluation with two different grading systems based on clinical imaging. Acta Radiol 2018; 59:327-335. [PMID: 28682110 DOI: 10.1177/0284185117715284] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background Several in vitro studies investigated how degeneration affects spinal motion. However, no consensus has emerged from these studies. Purpose To investigate how degeneration grading systems influence the kinematic output of spinal specimens. Material and Methods Flexibility testing was performed with ten human T12-S1 specimens. Degeneration was graded using two different classifications, one based on X-ray and the other one on magnetic resonance imaging (MRI). Intersegmental rotation (expressed by range of motion [ROM] and neutral zone [NZ]) was determined in all principal motion directions. Further, shear translation was measured during flexion/extension motion. Results The X-ray grading system yielded systematically lesser degeneration. In flexion/extension, only small differences in ROM and NZ were found between moderately degenerated motion segments, with only NZ for the MRI grading reaching statistical significance. In axial rotation, a significant increase in NZ for moderately degenerated segments was found for both grading systems, whereas the difference in ROM was significant only for the MRI scheme. Generally, the relative increases were more pronounced for the MRI classification compared to the X-ray grading scheme. In lateral bending, only relatively small differences between the degeneration groups were found. When evaluating shear translations, a non-significant increase was found for moderately degenerated segments. Motion segment segments tended to regain stability as degeneration progressed without reaching the level of statistical significance. Conclusion We found a fair agreement between the grading schemes which, nonetheless, yielded similar degeneration-related effects on intersegmental kinematics. However, as the trends were more pronounced using the Pfirrmann classification, this grading scheme appears superior for degeneration assessment.
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Affiliation(s)
- David Volkheimer
- Institute of Orthopedic Research and Biomechanics, Trauma Research Center Ulm (ZTF), University Hospital Ulm, Germany
| | | | - Christian Liebsch
- Institute of Orthopedic Research and Biomechanics, Trauma Research Center Ulm (ZTF), University Hospital Ulm, Germany
| | - Sabine Schlegel
- Institute of Epidemiology and Medical Biometry, Ulm University, Germany
| | | | | | - Hans-Joachim Wilke
- Institute of Orthopedic Research and Biomechanics, Trauma Research Center Ulm (ZTF), University Hospital Ulm, Germany
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Wagnac E, Aubin CÉ, Chaumoître K, Mac-Thiong JM, Ménard AL, Petit Y, Garo A, Arnoux PJ. Substantial vertebral body osteophytes protect against severe vertebral fractures in compression. PLoS One 2017; 12:e0186779. [PMID: 29065144 PMCID: PMC5655488 DOI: 10.1371/journal.pone.0186779] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 10/06/2017] [Indexed: 11/19/2022] Open
Abstract
Recent findings suggest that vertebral osteophytes increase the resistance of the spine to compression. However, the role of vertebral osteophytes on the biomechanical response of the spine under fast dynamic compression, up to failure, is unclear. Seventeen human spine specimens composed of three vertebrae (from T5-T7 to T11-L1) and their surrounding soft tissues were harvested from nine cadavers, aged 77 to 92 years. Specimens were imaged using quantitative computer tomography (QCT) for medical observation, classification of the intervertebral disc degeneration (Thomson grade) and measurement of the vertebral trabecular density (VTD), height and cross-sectional area. Specimens were divided into two groups (with (n = 9) or without (n = 8) substantial vertebral body osteophytes) and compressed axially at a dynamic displacement rate of 1 m/s, up to failure. Normalized force-displacement curves, videos and QCT images allowed characterizing failure parameters (force, displacement and energy at failure) and fracture patterns. Results were analyzed using chi-squared tests for sampling distributions and linear regression for correlations between VTD and failure parameters. Specimens with substantial vertebral body osteophytes present higher stiffness (2.7 times on average) and force at failure (1.8 times on average) than other segments. The presence of osteophytes significantly influences the location, pattern and type of fracture. VTD was a good predictor of the dynamic force and energy at failure for specimens without substantial osteophytes. This study also showed that vertebral body osteophytes provide a protective mechanism to the underlying vertebra against severe compression fractures.
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Affiliation(s)
- Eric Wagnac
- Department of Mechanical Engineering, École de technologie supérieure, Montréal, Québec, Canada
- Research Center, Sacré-Cœur Hospital, Montreal, Quebec, Canada
- iLAB-Spine, Associated International Laboratory on Spine Biomechanics and Imagery, Montreal, Canada
- * E-mail:
| | - Carl-Éric Aubin
- iLAB-Spine, Associated International Laboratory on Spine Biomechanics and Imagery, Montreal, Canada
- Department of Mechanical Engineering, École Polytechnique de Montréal, Montreal, Canada
- Research Center, Sainte-Justine University Hospital Center, Montreal, Quebec, Canada
| | - Kathia Chaumoître
- Department of medical imaging, North Hospital, Aix Marseille Université, Marseille, France
- Laboratoire d’Anthropologie Biologique, Aix Marseille Université, Marseille, France
| | - Jean-Marc Mac-Thiong
- Research Center, Sacré-Cœur Hospital, Montreal, Quebec, Canada
- Research Center, Sainte-Justine University Hospital Center, Montreal, Quebec, Canada
- Department of Surgery, Faculty of medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Anne-Laure Ménard
- Department of Mechanical Engineering, École de technologie supérieure, Montréal, Québec, Canada
| | - Yvan Petit
- Department of Mechanical Engineering, École de technologie supérieure, Montréal, Québec, Canada
- Research Center, Sacré-Cœur Hospital, Montreal, Quebec, Canada
- iLAB-Spine, Associated International Laboratory on Spine Biomechanics and Imagery, Montreal, Canada
| | - Anaïs Garo
- Department of Mechanical Engineering, École Polytechnique de Montréal, Montreal, Canada
- Laboratoire de Biomécanique Appliquée, IFSTTAR Aix Marseille Université, Marseille, France
| | - Pierre-Jean Arnoux
- Laboratoire de Biomécanique Appliquée, IFSTTAR Aix Marseille Université, Marseille, France
- iLAB-Spine, Associated International Laboratory on Spine Biomechanics and Imagery, Marseille, France
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Calvo-Echenique A, Cegoñino J, Correa-Martín L, Bances L, Palomar APD. Intervertebral disc degeneration: an experimental and numerical study using a rabbit model. Med Biol Eng Comput 2017; 56:865-877. [DOI: 10.1007/s11517-017-1738-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 10/09/2017] [Indexed: 11/25/2022]
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Li QY, Kim HJ, Son J, Kang KT, Chang BS, Lee CK, Seok HS, Yeom JS. Biomechanical analysis of lumbar decompression surgery in relation to degenerative changes in the lumbar spine - Validated finite element analysis. Comput Biol Med 2017; 89:512-519. [PMID: 28910701 DOI: 10.1016/j.compbiomed.2017.09.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 09/01/2017] [Accepted: 09/01/2017] [Indexed: 11/18/2022]
Abstract
BACKGROUND There are no studies about the biomechanical analysis of lumbar decompression surgery in relation to degenerative changes of the lumbar spine. Therefore, the purpose of this study was to compare, by using finite element (FE) analysis, the biomechanical changes of the lumbar spine in terms of annulus stress and nucleus pressure after two different kinds of lumbar decompression surgery in relation to disc degenerative changes. METHODS The validated intact and degenerated FE models (L2-5) were used in this study. In these two models, two different decompression surgical scenarios at L3-4, including conventional laminectomy (ConLa) and the spinous process osteotomy (SpinO), were simulated. Therefore, a total of six models were simulated. Under preloading, 7.5 Nm moments of flexion, extension, lateral bending, and torsion were imposed. In each model, the maximal von Mises stress on the annulus fibrosus and nucleus pressure at the index segment (L3-4) and adjacent segments (L2-3 and L4-5) were analyzed. RESULTS The ConLa model and disc degeneration model demonstrated a larger annulus stress at the decompression level (L3-4) under all four moments than were seen in the SpinO model and healthy disc model, respectively. Therefore, the ConLa model with moderate disc degeneration showed the highest annulus stress at the decompression level (L3-4). However, the percent change of annulus stress at L3-4 from the intact model to the matched decompression model was less in the moderate disc degeneration model than in the healthy disc model. CONCLUSIONS Although the ConLa model with moderate disc degeneration showed the highest annulus stress, the degenerative models would be less influenced by the decompression technique.
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Affiliation(s)
- Quan You Li
- Spine Center and Department of Orthopaedic Surgery, Seoul National University College of Medicine and Seoul National University Bundang Hospital, 166 Gumiro, Bundang-gu, Sungnam, 463-707, Republic of Korea
| | - Ho-Joong Kim
- Spine Center and Department of Orthopaedic Surgery, Seoul National University College of Medicine and Seoul National University Bundang Hospital, 166 Gumiro, Bundang-gu, Sungnam, 463-707, Republic of Korea.
| | - Juhyun Son
- Department of Mechanical Engineering, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul, Republic of Korea
| | - Kyoung-Tak Kang
- Department of Mechanical Engineering, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul, Republic of Korea.
| | - Bong-Soon Chang
- Department of Orthopaedic Surgery, Seoul National University College of Medicine and Seoul National University Hospital, 101 Daehangno, Jongno-gu, Seoul, 110-744, Republic of Korea
| | - Choon-Ki Lee
- Department of Orthopaedic Surgery, Seoul National University College of Medicine and Seoul National University Hospital, 101 Daehangno, Jongno-gu, Seoul, 110-744, Republic of Korea
| | - Hyun Sik Seok
- Spine Center and Department of Orthopaedic Surgery, Seoul National University College of Medicine and Seoul National University Bundang Hospital, 166 Gumiro, Bundang-gu, Sungnam, 463-707, Republic of Korea
| | - Jin S Yeom
- Spine Center and Department of Orthopaedic Surgery, Seoul National University College of Medicine and Seoul National University Bundang Hospital, 166 Gumiro, Bundang-gu, Sungnam, 463-707, Republic of Korea
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A finite element study of traditional Chinese cervical manipulation. 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 2017; 26:2308-2317. [DOI: 10.1007/s00586-017-5193-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2016] [Revised: 06/07/2017] [Accepted: 06/11/2017] [Indexed: 12/11/2022]
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Casaroli G, Galbusera F, Jonas R, Schlager B, Wilke HJ, Villa T. A novel finite element model of the ovine lumbar intervertebral disc with anisotropic hyperelastic material properties. PLoS One 2017; 12:e0177088. [PMID: 28472100 PMCID: PMC5417645 DOI: 10.1371/journal.pone.0177088] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 04/21/2017] [Indexed: 12/31/2022] Open
Abstract
The Ovine spine is an accepted model to investigate the biomechanical behaviour of the human lumbar one. Indeed, the use of animal models for in vitro studies is necessary to investigate the mechanical behaviour of biological tissue, but needs to be reduced for ethical and social reasons. The aim of this study was to create a finite element model of the lumbar intervertebral disc of the sheep that may help to refine the understanding of parallel in vitro experiments and that can be used to predict when mechanical failure occurs. Anisotropic hyperelastic material properties were assigned to the annulus fibrosus and factorial optimization analyses were performed to find out the optimal parameters of the ground substance and of the collagen fibers. For the ground substance of the annulus fibrosus the investigation was based on experimental data taken from the literature, while for the collagen fibers tensile tests on annulus specimens were conducted. Flexibility analysis in flexion-extension, lateral bending and axial rotation were conducted. Different material properties for the anterior, lateral and posterior regions of the annulus were found. The posterior part resulted the stiffest region in compression whereas the anterior one the stiffest region in tension. Since the flexibility outcomes were in a good agreement with the literature data, we considered this model suitable to be used in conjunction with in vitro and in vivo tests to investigate the mechanical behaviour of the ovine lumbar disc.
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Affiliation(s)
- Gloria Casaroli
- Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
| | | | - René Jonas
- Institute of Orthopaedic Research and Biomechanics, Center for Musculoskeletal Research (zmfu), Ulm University, Ulm, Germany
| | - Benedikt Schlager
- Institute of Orthopaedic Research and Biomechanics, Center for Musculoskeletal Research (zmfu), Ulm University, Ulm, Germany
| | - Hans-Joachim Wilke
- Institute of Orthopaedic Research and Biomechanics, Center for Musculoskeletal Research (zmfu), Ulm University, Ulm, Germany
| | - Tomaso Villa
- Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Milan, Italy
- IRCCS Istituto Ortopedico Galeazzi, Milan, Italy
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Casaroli G, Villa T, Bassani T, Berger-Roscher N, Wilke HJ, Galbusera F. Numerical Prediction of the Mechanical Failure of the Intervertebral Disc under Complex Loading Conditions. MATERIALS (BASEL, SWITZERLAND) 2017; 10:E31. [PMID: 28772392 PMCID: PMC5344546 DOI: 10.3390/ma10010031] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Revised: 12/06/2016] [Accepted: 12/20/2016] [Indexed: 11/16/2022]
Abstract
Finite element modeling has been widely used to simulate the mechanical behavior of the intervertebral disc. Previous models have been generally limited to the prediction of the disc behavior under simple loading conditions, thus neglecting its response to complex loads, which may induce its failure. The aim of this study was to generate a finite element model of the ovine lumbar intervertebral disc, in which the annulus was characterized by an anisotropic hyperelastic formulation, and to use it to define which mechanical condition was unsafe for the disc. Based on published in vitro results, numerical analyses under combined flexion, lateral bending, and axial rotation with a magnitude double that of the physiological ones were performed. The simulations showed that flexion was the most unsafe load and an axial tensile stress greater than 10 MPa can cause disc failure. The numerical model here presented can be used to predict the failure of the disc under all loading conditions, which may support indications about the degree of safety of specific motions and daily activities, such as weight lifting.
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Affiliation(s)
- Gloria Casaroli
- Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, 20133 Milan, Italy.
| | - Tomaso Villa
- Laboratory of Biological Structure Mechanics (LaBS), Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, 20133 Milan, Italy.
- IRCCS Istituto Ortopedico Galeazzi, 20161 Milan, Italy.
| | - Tito Bassani
- IRCCS Istituto Ortopedico Galeazzi, 20161 Milan, Italy.
| | - Nikolaus Berger-Roscher
- Institute of Orthopedic Research and Biomechanics, Trauma Research Center Ulm (ZTF), Ulm University, D-89081 Ulm, Germany.
| | - Hans-Joachim Wilke
- Institute of Orthopedic Research and Biomechanics, Trauma Research Center Ulm (ZTF), Ulm University, D-89081 Ulm, Germany.
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Moderately degenerated lumbar motion segments: Are they truly unstable? Biomech Model Mechanobiol 2016; 16:537-547. [PMID: 27664020 PMCID: PMC5350258 DOI: 10.1007/s10237-016-0835-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 09/14/2016] [Indexed: 11/17/2022]
Abstract
The two main load bearing tissues of the intervertebral disc are the nucleus pulposus and the annulus fibrosus. Both tissues are composed of the same basic components, but differ in their organization and relative amounts. With degeneration, the clear distinction between the two tissues disappears. The changes in biochemical content lead to changes in mechanical behaviour of the intervertebral disc. The aim of the current study was to investigate if well-documented moderate degeneration at the biochemical and fibre structure level leads to instability of the lumbar spine. By taking into account biochemical and ultrastructural changes to the extracellular matrix of degenerating discs, a set of constitutive material parameters were determined that described the individual tissue behaviour. These tissue biomechanical models were then used to simulate dynamic behaviour of the degenerated spinal motion segment, which showed instability in axial rotation, while a stabilizing effect in the other two principle bending directions. When a shear load was applied to the degenerated spinal motion segment, no sign of instability was found. This study found that reported changes to the nucleus pulposus and annulus fibrosus matrix during moderate degeneration lead to a more stable spinal motion segment and that such biomechanical considerations should be incorporated into the general pathophysiological understanding of disc degeneration and how its progress could affect low back pain and its treatments thereof.
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Li Y, Samartzis D, Campbell DD, Cherny SS, Cheung KMC, Luk KDK, Karppinen J, Song Y, Cheah KS, Chan D, Sham PC. Two subtypes of intervertebral disc degeneration distinguished by large-scale population-based study. Spine J 2016; 16:1079-89. [PMID: 27157501 DOI: 10.1016/j.spinee.2016.04.020] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 04/23/2016] [Accepted: 04/28/2016] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Lumbar disc degeneration (LDD) is a major cause of low back pain, and is a common and disabling condition worldwide. It has been defined and measured by multiple spine magnetic resonance imaging (MRI) features, but the heterogeneity among them has never been fully addressed. PURPOSE This study examined the intercorrelations, risk factor associations, and single nucleotide polymorphism (SNP) heritabilities of lumbar disc MRI features in a large-scale sample to classify the different intervertebral disc phenotypes associated with LDD. STUDY DESIGN A cross-sectional study was conducted consisting of 2,943 volunteers of Southern Chinese origin (mean age: 41.1 years; range: 15-55 years; 59.6% women). OUTCOME MEASURES The outcome measures were MRI phenotypic spinal patterns and their risk factor profiles in relation to developmental or degenerative origins of disc degeneration. METHODS Sagittal T2-weighted MRI of the lumbar spine from L1 to S1 was assessed. The MRI features of lumbar intervertebral disc changes, such as disc signal intensity loss and disc bulges or extrusions, as well as additional imaging phenotypes of end plate changes, high-intensity zones, and bone marrow changes, were evaluated. Blood samples were taken for genotyping using the HumanOmni-ZhongHua-8 BeadChip. Subject demographics, environmental, and lifestyle factors were assessed by questionnaires. Multivariate statistical techniques were used for phenotype evaluation. Polychoric correlations and local regression statistical analyses were performed. The genetic components contributed by common SNPs were estimated by comparing genetic correlations and phenotypic correlations using the Genome-Wide Complex Trait Analysis (GCTA) tool. RESULTS The study noted that lumbar disc MRI features separated into two groups with differential patterns of risk factor associations. A subset of lumbar disc abnormalities, including end plate changes but also upper lumbar disc bulging and signal intensity loss, may have a developmental origin. Subsequent degenerative changes, typically affecting the lower lumbar discs, then emerge as individuals age and are associated with body mass index. CONCLUSIONS This is the first large-scale study to identify two distinct patterns of lumbar disc alterations, noting degenerative changes and a possible developmental component affecting the lumbar spine. This new classification provides a starting point for a more homogeneous phenotype definition, which may provide greater statistical power and precision in future genetic and epidemiologic studies. In addition, such insights may have direct clinical implications in the prevention, therapeutics, and prognostics of patients with disc degeneration.
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Affiliation(s)
- Yan Li
- Centre for Genomic Sciences, The University of Hong Kong, 5 Sassoon Rd, Pokfulam, Hong Kong SAR, China; Department of Psychiatry, The University of Hong Kong, Queen Mary Hospital, 102 Pokfulam Road, Pokfulam, Hong Kong SAR, China
| | - Dino Samartzis
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Professorial Block, 5th Floor, 102 Pokfulam Rd, Pokfulam, Hong Kong SAR, China
| | - Desmond D Campbell
- Centre for Genomic Sciences, The University of Hong Kong, 5 Sassoon Rd, Pokfulam, Hong Kong SAR, China; Department of Psychiatry, The University of Hong Kong, Queen Mary Hospital, 102 Pokfulam Road, Pokfulam, Hong Kong SAR, China
| | - Stacey S Cherny
- Centre for Genomic Sciences, The University of Hong Kong, 5 Sassoon Rd, Pokfulam, Hong Kong SAR, China; Department of Psychiatry, The University of Hong Kong, Queen Mary Hospital, 102 Pokfulam Road, Pokfulam, Hong Kong SAR, China
| | - Kenneth M C Cheung
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Professorial Block, 5th Floor, 102 Pokfulam Rd, Pokfulam, Hong Kong SAR, China
| | - Keith D K Luk
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Professorial Block, 5th Floor, 102 Pokfulam Rd, Pokfulam, Hong Kong SAR, China
| | - Jaro Karppinen
- Medical Research Center Oulu, University of Oulu, Pentti Kaiteran katu 190570, Oulu, Finland; Oulu University Hospital, Center for Life Course Health Research, University of Oulu, Pentti Kaiteran katu 190570, Oulu, Finland; Finnish Institute of Occupational Health, Pentti Kaiteran katu 190570, Oulu, Finland
| | - Youqiang Song
- School of Biomedical Sciences, The University of Hong Kong, Laboratory Block, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China
| | - Kathryn S Cheah
- School of Biomedical Sciences, The University of Hong Kong, Laboratory Block, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China
| | - Danny Chan
- School of Biomedical Sciences, The University of Hong Kong, Laboratory Block, 21 Sassoon Road, Pokfulam, Hong Kong SAR, China
| | - Pak C Sham
- Centre for Genomic Sciences, The University of Hong Kong, 5 Sassoon Rd, Pokfulam, Hong Kong SAR, China; Department of Psychiatry, The University of Hong Kong, Queen Mary Hospital, 102 Pokfulam Road, Pokfulam, Hong Kong SAR, China.
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Stokes IAF, Gardner-Morse M. A database of lumbar spinal mechanical behavior for validation of spinal analytical models. J Biomech 2016; 49:780-785. [PMID: 26900035 DOI: 10.1016/j.jbiomech.2016.01.035] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 01/09/2016] [Accepted: 01/28/2016] [Indexed: 01/09/2023]
Abstract
Data from two experimental studies with eight specimens each of spinal motion segments and/or intervertebral discs are presented in a form that can be used for comparison with finite element model predictions. The data include the effect of compressive preload (0, 250 and 500N) with quasistatic cyclic loading (0.0115Hz) and the effect of loading frequency (1, 0.1, 0.01 and 0.001Hz) with a physiological compressive preload (mean 642N). Specimens were tested with displacements in each of six degrees of freedom (three translations and three rotations) about defined anatomical axes. The three forces and three moments in the corresponding axis system were recorded during each test. Linearized stiffness matrices were calculated that could be used in multi-segmental biomechanical models of the spine and these matrices were analyzed to determine whether off-diagonal terms and symmetry assumptions should be included. These databases of lumbar spinal mechanical behavior under physiological conditions quantify behaviors that should be present in finite element model simulations. The addition of more specimens to identify sources of variability associated with physical dimensions, degeneration, and other variables would be beneficial. Supplementary data provide the recorded data and Matlab® codes for reading files. Linearized stiffness matrices derived from the tests at different preloads revealed few significant unexpected off-diagonal terms and little evidence of significant matrix asymmetry.
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Affiliation(s)
- Ian A F Stokes
- University of Vermont, Department of Orthopaedics and Rehabilitation, Burlington, VT 05405-0084, USA.
| | - Mack Gardner-Morse
- University of Vermont, Department of Orthopaedics and Rehabilitation, Burlington, VT 05405-0084, USA
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Zagra A, Scaramuzzo L, Galbusera F, Minoia L, Archetti M, Giudici F. Biomechanical and clinical study of single posterior oblique cage POLIF in the treatment of degenerative diseases of the lumbar spine. 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 2015; 24 Suppl 7:924-30. [PMID: 26441256 DOI: 10.1007/s00586-015-4273-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 10/01/2015] [Accepted: 10/01/2015] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Aim of the study was to evaluate the biomechanical stability and the clinical efficacy of a lumbar interbody fusion obtained by single oblique cage implanted by a posterior approach. METHOD Through the realization of three finite element models (FEMs), the biomechanics of POLIF was compared to PLIF and TLIF. Ninety-four patients underwent interbody fusion by POLIF with instrumented posterolateral fusion. Clinical and radiographic outcomes were evaluated at regular intervals for at least 6 months. RESULTS The FEMs showed no statistically significant differences in stability in compression and flexion-extension. Mean preoperative VAS score was 7.1, decreased to 2.1 at follow-up. Mean preoperative SF-12 value was 34.5 %, increased to 75.4 % at follow-up. All patients showed a good fusion rate and no hardware failure. DISCUSSION POLIF associated to instrumented posterolateral fusion is a viable and safe surgical technique, which ensures a biomechanical stability similar to other surgical techniques.
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Affiliation(s)
- Antonino Zagra
- Spinal Division I, I.R.C.C.S. Galeazzi Orthopedic Institute, Via R. Galeazzi 4, 20161, Milan, Italy
| | - Laura Scaramuzzo
- Spinal Division I, I.R.C.C.S. Galeazzi Orthopedic Institute, Via R. Galeazzi 4, 20161, Milan, Italy.
| | | | - Leone Minoia
- Spinal Division I, I.R.C.C.S. Galeazzi Orthopedic Institute, Via R. Galeazzi 4, 20161, Milan, Italy
| | - Marino Archetti
- Spinal Division I, I.R.C.C.S. Galeazzi Orthopedic Institute, Via R. Galeazzi 4, 20161, Milan, Italy
| | - Fabrizio Giudici
- Spinal Division I, I.R.C.C.S. Galeazzi Orthopedic Institute, Via R. Galeazzi 4, 20161, Milan, Italy
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Fan R, Gong H, Qiu S, Zhang X, Fang J, Zhu D. Effects of resting modes on human lumbar spines with different levels of degenerated intervertebral discs: a finite element investigation. BMC Musculoskelet Disord 2015; 16:221. [PMID: 26300114 PMCID: PMC4546817 DOI: 10.1186/s12891-015-0686-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 08/14/2015] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND The negative effect of long-term working load on lumbar is widely known. However, insertion of different resting modes on long-term working load, and its effects on the lumbar spine is rarely studied. The purpose of this study was to investigate the biomechanical responses of lumbar spine with different levels of degenerated intervertebral discs under different working-resting modes. METHODS Four poroelastic finite element models of lumbar spinal segments L2-L3 with different grades of disc degeneration were developed. Four different loading conditions represented four different resting frequencies, namely, no rest, one-time long rest, three-time moderate rests, and five-time short rests, on the condition that the total resting time was the same except in the no rest mode. Loading amplitudes of diurnal activities included 100 N, 300 N, and 500 N. RESULTS With increasing resting frequency, the axial effective stress and fluid loss decreased, whereas the pore pressure and radial displacement increased. Under different resting frequencies, the changing rate of each biomechanical parameter was different. CONCLUSIONS Under a situation of fixed total resting time, high resting frequency was advisable. If sufficient resting frequency was unavailable for healthy people as well as patients with mildly and moderately degenerated intervertebral discs, they could similarly benefit from relatively less resting frequencies. However, one-time rest will not be useful in cases where intervertebral discs were seriously degenerated. Reasonable working-resting modes for different degrees of disc degeneration, which could assist patients achieve a better restoration, were provided in this study.
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Affiliation(s)
- Ruoxun Fan
- Department of Engineering Mechanics, Nanling Campus, Jilin University, Changchun, 130025, P. R. China.
| | - He Gong
- Department of Engineering Mechanics, Nanling Campus, Jilin University, Changchun, 130025, P. R. China.
| | - Sen Qiu
- State Key Laboratory of Automotive Simulation and Control, Jilin University, Changchun, 130025, P. R. China.
| | - Xianbin Zhang
- Department of Engineering Mechanics, Nanling Campus, Jilin University, Changchun, 130025, P. R. China.
| | - Juan Fang
- Department of Engineering Mechanics, Nanling Campus, Jilin University, Changchun, 130025, P. R. China.
| | - Dong Zhu
- Department of Orthopedic Surgery, No. 1 Hospital of Jilin University, Changchun, 130025, People's Republic of China.
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Tsouknidas A, Sarigiannidis SO, Anagnostidis K, Michailidis N, Ahuja S. Assessment of stress patterns on a spinal motion segment in healthy versus osteoporotic bony models with or without disc degeneration: a finite element analysis. Spine J 2015; 15:S17-S22. [PMID: 25576902 DOI: 10.1016/j.spinee.2014.12.148] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 12/29/2014] [Accepted: 12/30/2014] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT With an increasing prevalence of low back pain, physicians strive to optimize the treatment of patients with degenerated motion segments. There exists a consensus in literature that osteoporotic patients exhibit nonphysiologic loading patterns, while degenerated intervertebral discs (IVDs) are also believed to alter spine biomechanics. PURPOSE To evaluate alterations occurring in lumbosacral spine biomechanics of an osteoporotic model, with or without IVD degeneration, when compared with a healthy spine segment. STUDY DESIGN The investigation was based on finite element (FE) analysis of a patient-specific lumbosacral spine model. METHODS A biorealistic model of a lumbosacral spine segment is introduced to determine the morbidity of disc degeneration and osteoporosis. The model was verified and validated for the purpose of the study and subjected to a dynamic FE analysis, considering anisotropic bone properties and solid ligamentous tissue. RESULTS The yielded results merit high clinical interest. Osteoporosis resulted in a nonuniform increase of facet joint loading, which was even more pronounced in the scenario simulating a degenerated disc. The results also revealed an enslavement of intradiscal pressure to the disc state (in the degenerated and superior adjacent level). CONCLUSIONS The investigation presented refined insight into the dynamic biomechanical response of a degenerated spine segment. The increase in the calculated occurring stresses was considered as critical in the motion segment adjacent and superior to the degenerated one. This suggests that prevalent trauma in a motion segment may be a symptomatic condition of a poorly treated formal pathology in the inferior spine level.
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Affiliation(s)
- Alexander Tsouknidas
- Mechanical Engineering Department, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece.
| | | | - Kleovoulos Anagnostidis
- University Hospital Llandough, Cardiff University Hospital of Wales, Heath Park, Cardiff CF14 4XW, UK
| | - Nikolaos Michailidis
- Mechanical Engineering Department, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece
| | - Sashin Ahuja
- University Hospital Llandough, Cardiff University Hospital of Wales, Heath Park, Cardiff CF14 4XW, UK
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Kim HJ, Chun HJ, Kang KT, Lee HM, Chang BS, Lee CK, Yeom JS. Finite element analysis for comparison of spinous process osteotomies technique with conventional laminectomy as lumbar decompression procedure. Yonsei Med J 2015; 56:146-53. [PMID: 25510758 PMCID: PMC4276748 DOI: 10.3349/ymj.2015.56.1.146] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
PURPOSE The purpose of this study was to evaluate and compare the biomechanical behavior of the lumbar spine after posterior decompression with the spinous process osteotomy (SPiO) technique or the conventional laminectomy (CL) technique using a finite element (FE) model. MATERIALS AND METHODS Three validated lumbar FE models (L2-5) which represented intact spine and two decompression models using SPiO and CL techniques at the L3-4 segment were developed. In each model, the ranges of motion, the maximal von Mises stress of the annulus fibrosus, and the intradiscal pressures at the index segment (L3-4) and adjacent segments (L2-3 and L4-5) under 7.5 Nm moments were analyzed. Facet contact forces were also compared among three models under the extension and torsion moments. RESULTS Compared to the intact model, the CL and SPiO models had increased range of motion and annulus stress at both the index segment (L3-4) and the adjacent segments under flexion and torsion. However, the SPiO model demonstrated a reduced range of motion and annulus stress than the CL model. Both CL and SPiO models had an increase of facet contact force at the L3-4 segment under the torsion moment compared to that of the intact model. Under the extension moment, however, three models demonstrated a similar facet contact force even at the L3-4 model. CONCLUSION Both decompression methods lead to postoperative segmental instability compared to the intact model. However, SPiO technique leads to better segmental stability compared to the CL technique.
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Affiliation(s)
- Ho-Joong Kim
- Spine Center and Department of Orthopedic Surgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Heoung-Jae Chun
- Department of Mechanical Engineering, Yonsei University, Seoul, Korea
| | - Kyoung-Tak Kang
- Department of Mechanical Engineering, Yonsei University, Seoul, Korea
| | - Hwan-Mo Lee
- Department of Orthopedic Surgery, Yonsei University College of Medicine, Seoul, Korea
| | - Bong-Soon Chang
- Department of Orthopedic Surgery, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea
| | - Choon-Ki Lee
- Department of Orthopedic Surgery, Seoul National University College of Medicine, Seoul National University Hospital, Seoul, Korea
| | - Jin-S Yeom
- Spine Center and Department of Orthopedic Surgery, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam, Korea.
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Xu HG, Yu YF, Zheng Q, Zhang W, Wang CD, Zhao XY, Tong WX, Wang H, Liu P, Zhang XL. Autophagy protects end plate chondrocytes from intermittent cyclic mechanical tension induced calcification. Bone 2014; 66:232-9. [PMID: 24970040 DOI: 10.1016/j.bone.2014.06.018] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Revised: 06/06/2014] [Accepted: 06/17/2014] [Indexed: 01/08/2023]
Abstract
Calcification of end plate chondrocytes is a major cause of intervertebral disc (IVD) degeneration. However, the underlying molecular mechanism of end plate chondrocyte calcification is still unclear. The aim of this study was to clarify whether autophagy in end plate chondrocytes could protect the calcification of end plate chondrocytes. Previous studies showed that intermittent cyclic mechanical tension (ICMT) contributes to the calcification of end plate chondrocytes in vitro. While autophagy serves as a cell survival mechanism, the relationship of autophagy and induced end plate chondrocyte calcification by mechanical tension in vitro is unknown. Thus, we investigated autophagy, the expression of the autophagy genes, Beclin-1 and LC3, and rat end plate chondrocyte calcification by ICMT. The viability of end plate chondrocytes was examined using the LIVE/DEAD viability/cytotoxicity kit. The reverse transcription-polymerase chain reaction and western blotting were used to detect the expression of Beclin-1; LC3; type I, II and X collagen; aggrecan; and Sox-9 genes. Immunofluorescent and fluorescent microscopy showed decreased autophagy in the 10- and 20-day groups loaded with ICMT. Additionally, Alizarin red and alkaline phosphatase staining detected the palpable calcification of end plate chondrocytes after ICMT treatment. We found that increased autophagy induced by short-term ICMT treatment was accompanied by an insignificant calcification of end plate chondrocytes. To the contrary, the suppressive autophagy inhibited by long-term ICMT was accompanied by a more significant calcification. The process of calcification induced by ICMT was partially resisted by increased autophagy activity induced by rapamycin, implicating that autophagy may prevent end plate chondrocyte calcification.
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Affiliation(s)
- Hong-guang Xu
- Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui 241001, China.
| | - Yun-fei Yu
- Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui 241001, China
| | - Quan Zheng
- Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui 241001, China
| | - Wei Zhang
- Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui 241001, China
| | - Chuang-dong Wang
- The Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), Shanghai Jiao Tong University School of Medicine (SJTUSM), 200025, China
| | - Xiao-yn Zhao
- The Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), Shanghai Jiao Tong University School of Medicine (SJTUSM), 200025, China
| | - Wen-xue Tong
- The Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), Shanghai Jiao Tong University School of Medicine (SJTUSM), 200025, China
| | - Hong Wang
- Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui 241001, China
| | - Ping Liu
- Department of Orthopedic Surgery, Yijishan Hospital, Wannan Medical College, Wuhu, Anhui 241001, China
| | - Xiao-ling Zhang
- The Key Laboratory of Stem Cell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences (SIBS), Chinese Academy of Sciences (CAS), Shanghai Jiao Tong University School of Medicine (SJTUSM), 200025, China.
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Larouche A, Becker A, Schiffmann J, Roghmann F, Gandaglia G, Hanna N, Tian Z, Perrotte P, Schlomm T, Graefen M, Ahyai S, Trinh QD, Karakiewicz PI, Sun M. Comparison between complication rates of laser prostatectomy electrocautery transurethral resection of the prostate: A population-based study. Can Urol Assoc J 2014; 8:E419-24. [PMID: 25024796 PMCID: PMC4081257 DOI: 10.5489/cuaj.1790] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
INTRODUCTION We compare the complication rates and length of stay (LOS) of laser transurethral resection of the prostate (L-TURP) versus electrocautery transurethral resection of the prostate (E-TURP) in a population-based cohort. L-TURP has shown enhanced intraoperative safety and equivalent efficacy relative to E-TURP in several high volume centres. METHODS Relying on the Florida Datafile as part of the Healthcare Cost and Utilization Project State Inpatient Databases (SID) between 2006 and 2008, we identified 8066 men with benign prostate hyperplasia who underwent L-TURP or E-TURP. Chi-square and Mann-Whitney tests were used to compare baseline characteristics. A multivariable linear regression model was used to analyze the effect of L-TURP versus E-TURP on complication rates and LOS. RESULTS Overall complication rates did not differ significantly for L-TURP compared to E-TURP in univariable (8.8 vs. 7.4%, p = 0.1) and multivariable analyses (odds ratio [OR]: 1.06, confidence interval [CI]: 0.85-1.32, p = 0.6). Individuals undergoing E-TURP were less likely to experience a LOS in excess of 1 day (46.2 vs. 59.7%, p < 0.001). A lower risk to experience a LOS in excess of 1 day was confirmed for patients undergoing L-TURP after a multivariable linear regression model (OR: 0.37, CI: 0.23-0.58, p < 0.001), but not for a LOS in excess of 2 days (OR: 0.96, CI: 0.83-1.10, p = 0.2). CONCLUSIONS Patient characteristics and perioperative safety were similar for L-TURP and E-TURP patients. However, LOS patterns demonstrated a modest benefit for L-TURP compared to E-TURP patients.
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Affiliation(s)
- Alexandre Larouche
- Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Centre, Montreal, QC
- Department of Urology, University of Montreal Health Centre, Montreal, QC
| | - Andreas Becker
- Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Centre, Montreal, QC
- Martini-Clinic, Prostate Cancer Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Department of Urology, University-Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Jonas Schiffmann
- Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Centre, Montreal, QC
- Martini-Clinic, Prostate Cancer Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Florian Roghmann
- Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Centre, Montreal, QC
- Department of Urology, Ruhr University Bochum, Marienhospital, Herne, Germany
| | - Giorgio Gandaglia
- Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Centre, Montreal, QC
- Department of Urology, Vita-Salute, San Raffaele University, Milan, Italy
| | - Nawar Hanna
- Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Centre, Montreal, QC
- Department of Urology, University of Montreal Health Centre, Montreal, QC
| | - Zhe Tian
- Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Centre, Montreal, QC
| | - Paul Perrotte
- Department of Urology, University of Montreal Health Centre, Montreal, QC
| | - Thorsten Schlomm
- Martini-Clinic, Prostate Cancer Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Department of Urology, Section for Translational Prostate Cancer Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Markus Graefen
- Martini-Clinic, Prostate Cancer Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Sascha Ahyai
- Department of Urology, University-Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Quoc-Dien Trinh
- Department of Surgery, Division of Urology, Brigham and Women's Hospital/Dana-Farber Cancer Institut, Harvard Medical School, Boston, MA
| | - Pierre I. Karakiewicz
- Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Centre, Montreal, QC
- Department of Urology, University of Montreal Health Centre, Montreal, QC
| | - Maxine Sun
- Cancer Prognostics and Health Outcomes Unit, University of Montreal Health Centre, Montreal, QC
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Qasim M, Natarajan RN, An HS, Andersson GB. Damage accumulation location under cyclic loading in the lumbar disc shifts from inner annulus lamellae to peripheral annulus with increasing disc degeneration. J Biomech 2014; 47:24-31. [DOI: 10.1016/j.jbiomech.2013.10.032] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 09/16/2013] [Accepted: 10/12/2013] [Indexed: 10/26/2022]
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Charles YP, Lima LVPC, Persohn S, Rouch P, Steib JP, Skalli W. Influence of an auxiliary facet system on intervertebral discs and adjacent facet joints. Spine J 2013; 13:1293-300. [PMID: 23988459 DOI: 10.1016/j.spinee.2013.06.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Revised: 11/16/2012] [Accepted: 06/01/2013] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Facet supplementation stabilizes after facetectomy and undercutting laminectomy. It is indicated in degenerative spondylolisthesis with moderate disc degeneration and dynamic stenosis. PURPOSE To determine the influence of an auxiliary facet system (AFS) on the instrumented disc, adjacent levels' discs, and facet joints and to compare it with fusion. STUDY DESIGN Finite element study. METHODS L3-L4, L4-L5, and L5-S1 were studied using a validated finite element model with prescribed displacements for an intact spine, lesion by facetectomy and undercutting laminectomy, AFS, and fusion at L4-L5. The distribution of segmental range of motion (ROM) and applied moments, von Mises stress at the annulus, and facet joint contact forces were calculated with rotations in all planes. Institutional support for implant evaluation and modeling was received by Clariance. RESULTS In flexion-extension and lateral bending, fusion decreased L4-L5 ROM and increased adjacent levels' ROM. Range of motion was similarly distributed with intact lesion and AFS. In axial rotation, L4-L5 ROM represented 33% with intact, 55% after lesion, 25% with AFS, and 21% with fusion. Fusion increased annulus stress at adjacent levels in flexion-extension and lateral bending, but decreased stress at L4-L5 compared with AFS. In axial rotation, von Mises stress was similar with fusion and AFS. Facet loading increased in extension and lateral bending with fusion. It was comparable for fusion and AFS in axial rotation. CONCLUSIONS This study suggests that the AFS stabilizes L4-L5 in axial rotation after facetectomy and undercutting laminectomy as fusion does. This is because of the cross-link that generates an increased annulus stress in axial rotation at adjacent levels. With imposed displacements, without in vivo compensation of the hips, the solicitation at adjacent levels' discs and facet joints is higher with fusion compared with AFS. Fusion decreases intradiscal stress at the instrumented level.
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Affiliation(s)
- Yann Philippe Charles
- Laboratoire de Biomécanique, Arts et Métiers ParisTech, Paris, France; Service de Chirurgie du Rachis, Hôpitaux Universitaires de Strasbourg, Fédération de Médecine Translationnelle, Université de Strasbourg, 1, Place de l'hôpital, B.P. 426, 67091 Strasbourg Cedex, France.
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Reitmaier S, Schmidt H, Ihler R, Kocak T, Graf N, Ignatius A, Wilke HJ. Preliminary investigations on intradiscal pressures during daily activities: an in vivo study using the merino sheep. PLoS One 2013; 8:e69610. [PMID: 23894509 PMCID: PMC3722231 DOI: 10.1371/journal.pone.0069610] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2013] [Accepted: 06/11/2013] [Indexed: 11/18/2022] Open
Abstract
Purpose Currently, no studies exist, which attest the suitability of the ovine intervertebral disc as a biomechanical in vivo model for preclinical tests of new therapeutic strategies of the human disc. By measuring the intradiscal pressure in vivo, the current study attempts to characterize an essential biomechanical parameter to provide a more comprehensive physiological understanding of the ovine intervertebral disc. Methods Intradiscal pressure (IDP) was measured for 24 hours within the discs L2-L3 and L4-L5 via a piezo-resistive pressure sensor in one merino sheep. The data were divided into an activity and a recovery phase and the corresponding average pressures for both phases were determined. Additionally, IDPs for different static and dynamic activities were analyzed and juxtaposed to human data published previously. After sacrificing the sheep, the forces corresponding to the measured IDPs were examined ex vivo in an axial compression test. Results The temporal patterns of IDP where pressure decreased during activity and increased during rest were comparable between humans and sheep. However, large differences were observed for different dynamic activities such as standing up or walking. Here, IDPs averaged 3.73 MPa and 1.60 MPa respectively, approximately two to four times higher in the ovine disc compared to human. These IDPs correspond to lower ex vivo derived axial compressive forces for the ovine disc in comparison to the human disc. For activity and rest, average ovine forces were 130 N and 58 N, compared to human forces of 400-600 N and 100 N, respectively. Conclusions In vivo IDPs were found to be higher in the ovine than in the human disc. In contrast, axial forces derived ex vivo were markedly lower in comparison to humans. Both should be considered in future preclinical tests of intradiscal therapies using the sheep. The techniques used in the current study may serve as a protocol for measuring IDP in a variety of large animal models.
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Affiliation(s)
- Sandra Reitmaier
- Institute of Orthopedic Research and Biomechanics, Center of Musculoskeletal Research, University of Ulm, Ulm, Germany.
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Ito K, Creemers L. Mechanisms of intervertebral disk degeneration/injury and pain: a review. Global Spine J 2013; 3:145-52. [PMID: 24436865 PMCID: PMC3854582 DOI: 10.1055/s-0033-1347300] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Accepted: 04/19/2013] [Indexed: 12/31/2022] Open
Abstract
Degeneration of the intervertebral disk and its treatments are currently intensely investigated topics. Back pain is a condition whose chronic and debilitating nature combined with its prevalence make it a major health issue of substantial socioeconomic importance. Although researchers, and even sometimes clinicians, focus on the degenerated disk as the problem, to most patients, pain is the factor that limits their function and impacts their well-being. The purpose of this review is to delineate the changes associated with disk degeneration and to outline mechanisms by which they could be the source of back pain. Although the healthy disk is only innervated in the external layer of its annulus fibrosus, adjacent structures are plentiful with nociceptive receptors. Stimulation of such structures as a consequence of processes initiated by disk degeneration is explored. The concept of discogenic pain and possible mechanisms such as neoinnervation and solute transport are discussed. Finally, how such pain mechanisms may relate to current and proposed treatment strategies is discussed.
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Affiliation(s)
- Keita Ito
- Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands,Address for correspondence Prof. Keita Ito, MD, ScD Orthopaedic Biomechanics, GEM-Z 4.115, Department of Biomedical EngineeringP.O. Box 513, 5600 MB EindhovenThe Netherlands
| | - Laura Creemers
- Department of Orthopaedics, University Medical Center Utrecht, Utrecht, The Netherlands
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Maquer G, Schwiedrzik J, Zysset PK. Embedding of human vertebral bodies leads to higher ultimate load and altered damage localisation under axial compression. Comput Methods Biomech Biomed Engin 2012; 17:1311-22. [DOI: 10.1080/10255842.2012.744400] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Ayturk UM, Gadomski B, Schuldt D, Patel V, Puttlitz CM. Modeling Degenerative Disk Disease in the Lumbar Spine: A Combined Experimental, Constitutive, and Computational Approach. J Biomech Eng 2012; 134:101003. [DOI: 10.1115/1.4007632] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Using a continuum approach for modeling the constitutive mechanical behavior of the intervertebral disk’s annulus fibrosus holds the potential for facilitating the correlation of morphology and biomechanics of this clinically important tissue. Implementation of a continuum representation of the disk’s tissues into computational models would yield a particularly valuable tool for investigating the effects of degenerative disease. However, to date, relevant efforts in the literature towards this goal have been limited due to the lack of a computationally tractable and implementable constitutive function. In order to address this, annular specimens harvested from a total of 15 healthy and degenerated intervertebral disks were tested under planar biaxial tension. Predictions of a strain energy function, which was previously shown to be unconditionally convex, were fit to the experimental data, and the optimized coefficients were used to modify a previously validated finite element model of the L4/L5 functional spinal unit. Optimization of material coefficients based on experimental results indicated increases in the micro-level orientation dispersion of the collagen fibers and the mechanical nonlinearity of these fibers due to degeneration. On the other hand, the finite element model predicted a progressive increase in the stress generation in annulus fibrosus due to stepwise degeneration of initially the nucleus and then the entire disk. Range of motion was predicted to initially increase with the degeneration of the nucleus and then decrease with the degeneration of the annulus in all rotational loading directions, except for axial rotation. Overall, degeneration was observed to specifically impact the functional effectiveness of the collagen fiber network of the annulus, leading to changes in the biomechanical behavior at both the tissue level and the motion-segment level.
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Affiliation(s)
- Ugur M. Ayturk
- Department of Orthopaedic Surgery, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02115
| | - Benjamin Gadomski
- Orthopaedic Bioengineering Research Laboratory, Department of Mechanical Engineering and School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523
| | - Dieter Schuldt
- Orthopaedic Bioengineering Research Laboratory, Department of Mechanical Engineering and School of Biomedical Engineering, Colorado State University, Fort Collins, CO 80523
| | - Vikas Patel
- The Spine Center, Department of Orthopaedics, University of Colorado Denver, Denver, CO 80045
| | - Christian M. Puttlitz
- Orthopaedic Bioengineering Research Laboratory, Department of Mechanical Engineering and School of Biomedical Engineering, Colorado State University, 1374 Campus Delivery, Fort Collins, CO 80523
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Qasim M, Natarajan RN, An HS, Andersson GBJ. Initiation and progression of mechanical damage in the intervertebral disc under cyclic loading using continuum damage mechanics methodology: A finite element study. J Biomech 2012; 45:1934-40. [PMID: 22682891 DOI: 10.1016/j.jbiomech.2012.05.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 05/10/2012] [Accepted: 05/13/2012] [Indexed: 10/28/2022]
Abstract
It is difficult to study the breakdown of disc tissue over several years of exposure to bending and lifting by experimental methods. There is also no finite element model that elucidates the failure mechanism due to repetitive loading of the lumbar motion segment. The aim of this study was to refine an already validated poro-elastic finite element model of lumbar motion segment to investigate the initiation and progression of mechanical damage in the disc under simple and complex cyclic loading conditions. Continuum damage mechanics methodology was incorporated into the finite element model to track the damage accumulation in the annulus in response to the repetitive loading. The analyses showed that the damage initiated at the posterior inner annulus adjacent to the endplates and propagated outwards towards its periphery under all loading conditions simulated. The damage accumulated preferentially in the posterior region of the annulus. The analyses also showed that the disc failure is unlikely to happen with repetitive bending in the absence of compressive load. Compressive cyclic loading with low peak load magnitude also did not create the failure of the disc. The finite element model results were consistent with the experimental and clinical observations in terms of the region of failure, magnitude of applied loads and the number of load cycles survived.
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Affiliation(s)
- Muhammad Qasim
- Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, USA
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Abstract
Degenerative changes in the material properties of nucleus pulposus and anulus fibrosus promote changes in viscoelastic properties of the whole disc. Volume, pressure and hydration loss in the nucleus pulposus, disk height decreases and fissures in the anulus fibrosus, are some of the signs of the degenerative cascade that advances with age and affect, among others, spinal function and its stability. Much remains to be learned about how these changes affect the function of the motion segment and relate to symptoms such as low back pain and altered spinal biomechanics.
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Affiliation(s)
- Nozomu Inoue
- Department of Orthopedic Surgery and Director of Spine Biomechanics Laboratory, Rush University Medical Center, Chicago, IL
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