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Zheng LD, Cao YT, Yang YT, Xu ML, Zeng HZ, Zhu SJ, Candito A, Chen Y, Zhu R, Cheng LM. Biomechanical response of lumbar intervertebral disc in daily sitting postures: a poroelastic finite element analysis. Comput Methods Biomech Biomed Engin 2023; 26:1941-1950. [PMID: 36576174 DOI: 10.1080/10255842.2022.2159760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 12/07/2022] [Accepted: 12/13/2022] [Indexed: 12/29/2022]
Abstract
This study aims to establish and validate a poroelastic L4-L5 finite element model to evaluate the effect of different sitting postures and their durations on the mechanical responses of the disc. During the sustained loading conditions, the height loss, fluid loss and von-Mises stress gradually increased, but the intradiscal pressure decreased. The varying rates of aforementioned parameters were more significant at the initial loading stage and less so at the end. The predicted values in the flexed sitting posture were significantly greater than other postures. The extended sitting posture caused an obvious von-Mises stress concentration in the posterior region of the inter-lamellar matrix. From the biomechanical perspective, prolonged sitting may pose a high risk of lumbar disc degeneration, and therefore adjusting the posture properly in the early stage of sitting time may be useful to mitigate that. Additionally, upright sitting is a safer posture, while flexed sitting posture is more harmful.
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Affiliation(s)
- Liang-Dong Zheng
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Yu-Ting Cao
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Yi-Ting Yang
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Meng-Lei Xu
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Hui-Zi Zeng
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Shi-Jie Zhu
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Antonio Candito
- Institute of Mechanical, Process and Energy Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Scotland, UK
| | - Yuhang Chen
- Institute of Mechanical, Process and Energy Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Scotland, UK
| | - Rui Zhu
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Li-Ming Cheng
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of Ministry of Education, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
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Modeling multiaxial damage regional variation in human annulus fibrosus. Acta Biomater 2021; 136:375-388. [PMID: 34547514 DOI: 10.1016/j.actbio.2021.09.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 09/08/2021] [Accepted: 09/13/2021] [Indexed: 01/03/2023]
Abstract
In the present article, a fully three-dimensional human annulus fibrosus model is developed by considering the regional variation of the complex structural organization of collagen network at different scales to predict the regional anisotropic multiaxial damage of the intervertebral disc. The model parameters are identified using experimental data considering as elementary structural unit, the single annulus lamellae stretched till failure along the micro-sized collagen fibers. The multi-layered lamellar/inter-lamellar annulus model is constructed by considering the effective interactions between adjacent layers and the chemical-induced volumetric strain. The regional dependent model predictions are analyzed under various loading modes and compared to experimental data when available. The stretching along the circumferential and radial directions till failure serves to check the predictive capacities of the annulus model. Model results under simple shear, biaxial stretching and plane-strain compression are further presented and discussed. Finally, a full disc model is constructed using the regional annulus model and simulations are presented to assess the most likely failed areas under disc axial compression. STATEMENT OF SIGNIFICANCE: The damage in annulus soft tissues is a complex multiscale phenomenon due to a complex structural arrangement of collagen network at different scales of hierarchical organization. A fully three-dimensional constitutive representation that considers the regional variation of the structural complexity to estimate annulus multiaxial mechanics till failure has not yet been developed. Here, a model is developed to predict deformation-induced damage and failure of annulus under multiaxial loading histories considering as time-dependent physical process both chemical-induced volumetric effects and damage accumulation. After model identification using single lamellae extracted from different disc regions, the model predictability is verified for various multiaxial elementary loading modes representative of the spine movement. The heterogeneous mechanics of a full human disc model is finally presented.
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Zhou M, Werbner B, O'Connell G. Historical Review of Combined Experimental and Computational Approaches for Investigating Annulus Fibrosus Mechanics. J Biomech Eng 2020; 142:030802. [PMID: 32005986 DOI: 10.1115/1.4046186] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Indexed: 07/25/2024]
Abstract
Intervertebral disc research has sought to develop a deeper understanding of spine biomechanics, the complex relationship between disc health and back pain, and the mechanisms of spinal injury and repair. To do so, many researchers have focused on characterizing tissue-level properties of the disc, where the roles of tissue subcomponents can be more systematically investigated. Unfortunately, experimental challenges often limit the ability to measure important disc tissue- and subtissue-level behaviors, including fiber-matrix interactions, transient nutrient and electrolyte transport, and damage propagation. Numerous theoretical and numerical modeling frameworks have been introduced to explain, complement, guide, and optimize experimental research efforts. The synergy of experimental and computational work has significantly advanced the field, and these two aspects have continued to develop independently and jointly. Meanwhile, the relationship between experimental and computational work has become increasingly complex and interdependent. This has made it difficult to interpret and compare results between experimental and computational studies, as well as between solely computational studies. This paper seeks to explore issues of model translatability, robustness, and efficient study design, and to propose and motivate potential future directions for experimental, computational, and combined tissue-level investigations of the intervertebral disc.
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Affiliation(s)
- Minhao Zhou
- Mechanical Engineering Department, University of California, Berkeley, 2162 Etcheverry Hall, #1740, Berkeley, CA 94720-1740
| | - Benjamin Werbner
- Mechanical Engineering Department, University of California, Berkeley, 2162 Etcheverry Hall, #1740, Berkeley, CA 94720-1740
| | - Grace O'Connell
- Mechanical Engineering Department, University of California, Berkeley, 5122 Etcheverry Hall, #1740, Berkeley, CA 94720-1740; Department of Orthopaedic Surgery, University of California, San Francisco, 513 Parnassus Ave., Suite S-1161, San Francisco, CA 94143
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Schwan S, Ludtka C, Wiesner I, Baerthel A, Friedmann A, Göhre F. Percutaneous posterolateral approach for the simulation of a far-lateral disc herniation in an ovine model. 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; 27:222-230. [PMID: 29080003 DOI: 10.1007/s00586-017-5362-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 10/10/2017] [Accepted: 10/19/2017] [Indexed: 01/08/2023]
Abstract
PURPOSE This work describes a minimally invasive damage model for ovine lumbar discs via partial nucleotomy using a posterolateral approach. METHODS Two cadavers were dissected to analyze the percutaneous corridor. Subsequently, 28 ovine had their annulus fibrosus punctured via awl penetration under fluoroscopic control and nucleus pulposus tissue removed via rongeur. Efficacy was assessed by animal morbidity, ease of access to T12-S1 disc spaces, and production of a mechanical injury as verified by discography, radiography, and histology. RESULTS T12-S1 were accessible with minimal nerve damage morbidity. Scar tissue sealed the disc puncture site in all animals within 6 weeks, withstanding 1 MP of intradiscal pressure. Partial nucleotomy led to a significant reduction in intervertebral disk height and an increased histological degeneration score. CONCLUSION Inducing a reproducible injury pattern of disc degeneration required minimal time, effort, and equipment. The posterolateral approach allows operation on several discs within a single surgery and multiple animal surgeries within a single day.
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Affiliation(s)
- Stefan Schwan
- Translational Centre of Regenerative Medicine TRM, University of Leipzig, Philipp-Rosenthal-Straße 55, 04103, Leipzig, Germany. .,Department of Biological and Macromolecular Materials, Fraunhofer Institute for Microstructure of Materials and Systems IMWS, Walter-Hülse-Str. 1, 06120, Halle (Saale), Germany.
| | - Christopher Ludtka
- Translational Centre of Regenerative Medicine TRM, University of Leipzig, Philipp-Rosenthal-Straße 55, 04103, Leipzig, Germany.,Department of Biological and Macromolecular Materials, Fraunhofer Institute for Microstructure of Materials and Systems IMWS, Walter-Hülse-Str. 1, 06120, Halle (Saale), Germany.,Department of Chemical and Biomolecular Engineering, University of Tennessee Knoxville, Knoxville, TN, USA
| | - Ingo Wiesner
- Department of General, Visceral and Vascular Surgery, BG-Klinik Bergmannstrost, Halle (Saale), Germany
| | - Andre Baerthel
- Translational Centre of Regenerative Medicine TRM, University of Leipzig, Philipp-Rosenthal-Straße 55, 04103, Leipzig, Germany
| | - Andrea Friedmann
- Translational Centre of Regenerative Medicine TRM, University of Leipzig, Philipp-Rosenthal-Straße 55, 04103, Leipzig, Germany.,Department of Biological and Macromolecular Materials, Fraunhofer Institute for Microstructure of Materials and Systems IMWS, Walter-Hülse-Str. 1, 06120, Halle (Saale), Germany
| | - Felix Göhre
- Translational Centre of Regenerative Medicine TRM, University of Leipzig, Philipp-Rosenthal-Straße 55, 04103, Leipzig, Germany.,Department of Neurosurgery, BG-Klinik Bergmannstrost, Halle (Saale), Germany.,Department of Neurosurgery, Helsinki University Central Hospital, Helsinki University, Helsinki, Finland
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Werbner B, Zhou M, O'Connell G. A Novel Method for Repeatable Failure Testing of Annulus Fibrosus. J Biomech Eng 2017; 139:2653977. [DOI: 10.1115/1.4037855] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Indexed: 11/08/2022]
Abstract
Tears in the annulus fibrosus (AF) of the intervertebral disk can result in disk herniation and progressive degeneration. Understanding AF failure mechanics is important as research moves toward developing biological repair strategies for herniated disks. Unfortunately, failure mechanics of fiber-reinforced tissues, particularly tissues with fibers oriented off-axis from the applied load, is not well understood, partly due to the high variability in reported mechanical properties and a lack of standard techniques ensuring repeatable failure behavior. Therefore, the objective of this study was to investigate the effectiveness of midlength (ML) notch geometries in producing repeatable and consistent tissue failure within the gauge region of AF mechanical test specimens. Finite element models (FEMs) representing several notch geometries were created to predict the location of bulk tissue failure using a local strain-based criterion. FEM results were validated by experimentally testing a subset of the modeled specimen geometries. Mechanical testing data agreed with model predictions (∼90% agreement), validating the model's predictive power. Two of the modified dog-bone geometries (“half” and “quarter”) effectively ensured tissue failure at the ML for specimens oriented along the circumferential-radial and circumferential-axial directions. The variance of measured mechanical properties was significantly lower for notched samples that failed at the ML, suggesting that ML notch geometries result in more consistent and reliable data. In addition, the approach developed in this study provides a framework for evaluating failure properties of other fiber-reinforced tissues, such as tendons and meniscus.
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Affiliation(s)
- Benjamin Werbner
- Mechanical Engineering Department, University of California, Berkeley, 2162 Etcheverry Hall, #1740, Berkeley, CA 94720-1740 e-mail:
| | - Minhao Zhou
- Mechanical Engineering Department, University of California, Berkeley, 2162 Etcheverry Hall, #1740, Berkeley, CA 94720-1740 e-mail:
| | - Grace O'Connell
- Mechanical Engineering Department, University of California, Berkeley, 5122 Etcheverry Hall, #1740, Berkeley, CA 94720-1740 e-mail:
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