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Davies B, Schaefer S, Rafati Fard A, Newcombe V, Sutcliffe M. Finite Element Analysis for Degenerative Cervical Myelopathy: Scoping Review of the Current Findings and Design Approaches, Including Recommendations on the Choice of Material Properties. JMIR BIOMEDICAL ENGINEERING 2024; 9:e48146. [PMID: 38875683 PMCID: PMC11041437 DOI: 10.2196/48146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 10/31/2023] [Accepted: 02/15/2024] [Indexed: 06/16/2024] Open
Abstract
BACKGROUND Degenerative cervical myelopathy (DCM) is a slow-motion spinal cord injury caused via chronic mechanical loading by spinal degenerative changes. A range of different degenerative changes can occur. Finite element analysis (FEA) can predict the distribution of mechanical stress and strain on the spinal cord to help understand the implications of any mechanical loading. One of the critical assumptions for FEA is the behavior of each anatomical element under loading (ie, its material properties). OBJECTIVE This scoping review aims to undertake a structured process to select the most appropriate material properties for use in DCM FEA. In doing so, it also provides an overview of existing modeling approaches in spinal cord disease and clinical insights into DCM. METHODS We conducted a scoping review using qualitative synthesis. Observational studies that discussed the use of FEA models involving the spinal cord in either health or disease (including DCM) were eligible for inclusion in the review. We followed the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews) guidelines. The MEDLINE and Embase databases were searched to September 1, 2021. This was supplemented with citation searching to retrieve the literature used to define material properties. Duplicate title and abstract screening and data extraction were performed. The quality of evidence was appraised using the quality assessment tool we developed, adapted from the Newcastle-Ottawa Scale, and shortlisted with respect to DCM material properties, with a final recommendation provided. A qualitative synthesis of the literature is presented according to the Synthesis Without Meta-Analysis reporting guidelines. RESULTS A total of 60 papers were included: 41 (68%) "FEA articles" and 19 (32%) "source articles." Most FEA articles (33/41, 80%) modeled the gray matter and white matter separately, with models typically based on tabulated data or, less frequently, a hyperelastic Ogden variant or linear elastic function. Of the 19 source articles, 14 (74%) were identified as describing the material properties of the spinal cord, of which 3 (21%) were considered most relevant to DCM. Of the 41 FEA articles, 15 (37%) focused on DCM, of which 9 (60%) focused on ossification of the posterior longitudinal ligament. Our aggregated results of DCM FEA indicate that spinal cord loading is influenced by the pattern of degenerative changes, with decompression alone (eg, laminectomy) sufficient to address this as opposed to decompression combined with other procedures (eg, laminectomy and fusion). CONCLUSIONS FEA is a promising technique for exploring the pathobiology of DCM and informing clinical care. This review describes a structured approach to help future investigators deploy FEA for DCM. However, there are limitations to these recommendations and wider uncertainties. It is likely that these will need to be overcome to support the clinical translation of FEA to DCM.
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Affiliation(s)
- Benjamin Davies
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Samuel Schaefer
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
| | - Amir Rafati Fard
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Virginia Newcombe
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Michael Sutcliffe
- Department of Engineering, University of Cambridge, Cambridge, United Kingdom
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Goertz AR, Yang KH, Viano DC. Development of a finite element biomechanical whole spine model for analyzing lumbar spine loads under caudocephalad acceleration. Biomed Phys Eng Express 2020; 7. [PMID: 35092949 DOI: 10.1088/2057-1976/abc89a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 11/09/2020] [Indexed: 11/12/2022]
Abstract
Background:Spine injury risk due to military conflict is an ongoing concern among defense organizations throughout the world. A better understanding of spine biomechanics could assist in developing protection devices to reduce injuries caused by caudocephalad acceleration (+Gz) in under-body blasts (UBB). Although some finite element (FE) human models have demonstrated reasonable lumbar spine biofidelity, they were either partial spine models or not validated for UBB-type loading modes at the lumbar functional spinal unit (FSU) level, thus limiting their ability to analyze UBB-associated occupant kinematics.Methods:An FE functional representation of the human spine with simplified geometry was developed to study the lumbar spine responses under +Gz loading. Fifty-seven load curves obtained from post mortem human subject experiments were used to optimize the model.Results:The model was cumulatively validated for compression, flexion, extension, and anterior-, posterior-, and lateral-shears of the lumbar spine and flexion and extension of the cervical spine. The thoracic spine was optimized for flexion and compression. The cumulative CORrelation and Analysis (CORA) rating for the lumbar spine was 0.766 and the cervical spine was 0.818; both surpassed the 0.7 objective goal. The model's element size was confirmed as converged.Conclusions:An FE functional representation of the human spine was developed for +Gz lumbar load analysis. The lumbar and cervical spines were demonstrated to be quantitatively biofidelic to the FSU level for multi-directional loading and bending typically experienced in +Gz loading, filling the capability gap in current models.
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Affiliation(s)
- Alan R Goertz
- Bioengineering Center, Wayne State University, 818 W Hancock, Detroit, MI 48201, United States of America.,SURVICE Engineering Company, 4687 Millennium Dr., Belcamp, MD 21017, United States of America
| | - King H Yang
- Bioengineering Center, Wayne State University, 818 W Hancock, Detroit, MI 48201, United States of America
| | - David C Viano
- ProBiomechanics LLC, 265 Warrington Rd., Bloomfield Hills, MI 48304-2952, United States of America
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Albert DL. Variations in User Implementation of the CORA Rating Metric. STAPP CAR CRASH JOURNAL 2020; 64:1-30. [PMID: 33636001 DOI: 10.4271/2020-22-0001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
The CORA rating metric is frequently used in the field of injury biomechanics to compare the similarity of response time histories. However, subjectivity exists within the CORA metric in the form of user-customizable parameters that give the metric the flexibility to be used for a variety of applications. How these parameters are customized is not always reported in the literature, and it is unknown how these customizations affect the CORA scores. Therefore, the purpose of this study was to evaluate how variations in the CORA parameters affect the resulting similarity scores. A literature review was conducted to determine how the CORA parameters are commonly customized within the literature. Then, CORA scores for two datasets were calculated using the most common parameter customizations and the default parameters. Differences between the CORA scores using customized and default parameters were statistically significant for all customizations. Furthermore, most customizations produced score increases relative to the default settings. The use of standard deviation corridors and exclusion of the corridor component were found to produce the largest score differences. The observed differences demonstrated the need for researchers to exercise transparency when using customized parameters in CORA analyses.
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Affiliation(s)
- Devon L Albert
- Center for Injury Biomechanics, Department of Biomedical Engineering and Mechanics, Virginia Tech
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Bailly N, Diotalevi L, Beauséjour MH, Wagnac É, Mac-Thiong JM, Petit Y. Numerical investigation of the relative effect of disc bulging and ligamentum flavum hypertrophy on the mechanism of central cord syndrome. Clin Biomech (Bristol, Avon) 2020; 74:58-65. [PMID: 32145670 DOI: 10.1016/j.clinbiomech.2020.02.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 02/07/2020] [Accepted: 02/13/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND The pathogenesis of the central cord syndrome is still unclear. While there is a consensus on hyperextension as the main traumatic mechanism leading to this condition, there is yet to be consensus in studies regarding the pathological features of the spine (intervertebral disc bulging or ligamentum flavum hypertrophy) that could contribute to clinical manifestations. METHODS A comprehensive finite element model of the cervical spine segment and spinal cord was used to simulate high-speed hyperextension. Four stenotic cases were modelled to study the effect of ligamentum flavum hypertrophy and intervertebral disc bulging on the von Mises stress and strain. FINDINGS During hyperextension, the downward displacement of the ligamentum flavum and a reduction of the spinal canal diameter (up to 17%) led to a dynamic compression of the cord. Ligamentum flavum hypertrophy was associated with stress and strain (peak of 0.011 Mpa and 0.24, respectively) in the lateral corticospinal tracts, which is consistent with the histologic pattern of the central cord syndrome. Linear intervertebral disc bulging alone led to a higher stress in the anterior and posterior funiculi (peak 0.029 Mpa). Combined with hypertrophic ligamentum flavum, it further increased the stress and strain in the corticospinal tracts and in the posterior horn (peak of 0.023 Mpa and 0.35, respectively). INTERPRETATION The stenotic typology and geometry greatly influence stress and strain distribution resulting from hyperextension. Ligamentum flavum hypertrophy is a main feature leading to central cord syndrome.
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Affiliation(s)
- Nicolas Bailly
- Department of Mechanical Engineering, École de technologie supérieure, 1100 Notre-Dame Street West, Montréal, Québec H3C 1K3, Canada; Research Center, Hôpital du Sacré-Cœur de Montréal, 5400 Gouin blvd, Montréal H4J 1C5, Québec, Canada; International Laboratory on Spine Imaging and Biomechanics (iLab-Spine), France
| | - Lucien Diotalevi
- Department of Mechanical Engineering, École de technologie supérieure, 1100 Notre-Dame Street West, Montréal, Québec H3C 1K3, Canada; Research Center, Hôpital du Sacré-Cœur de Montréal, 5400 Gouin blvd, Montréal H4J 1C5, Québec, Canada; International Laboratory on Spine Imaging and Biomechanics (iLab-Spine), France
| | - Marie-Hélène Beauséjour
- Department of Mechanical Engineering, École de technologie supérieure, 1100 Notre-Dame Street West, Montréal, Québec H3C 1K3, Canada; Research Center, Hôpital du Sacré-Cœur de Montréal, 5400 Gouin blvd, Montréal H4J 1C5, Québec, Canada; International Laboratory on Spine Imaging and Biomechanics (iLab-Spine), France; Laboratoire de Biomécanique Appliquée, UMRT24 IFSTTAR- Université de la Méditerranée, F-13916 Marseille cedex 20, France
| | - Éric Wagnac
- Department of Mechanical Engineering, École de technologie supérieure, 1100 Notre-Dame Street West, Montréal, Québec H3C 1K3, Canada; Research Center, Hôpital du Sacré-Cœur de Montréal, 5400 Gouin blvd, Montréal H4J 1C5, Québec, Canada; International Laboratory on Spine Imaging and Biomechanics (iLab-Spine), France
| | - Jean-Marc Mac-Thiong
- Research Center, Hôpital du Sacré-Cœur de Montréal, 5400 Gouin blvd, Montréal H4J 1C5, Québec, Canada; Department of Orthopaedic Surgery, Université de Montréal, P.O. box 6128, Station Centre-Ville, Montréal, Québec H3C 3J7, Canada
| | - Yvan Petit
- Department of Mechanical Engineering, École de technologie supérieure, 1100 Notre-Dame Street West, Montréal, Québec H3C 1K3, Canada; Research Center, Hôpital du Sacré-Cœur de Montréal, 5400 Gouin blvd, Montréal H4J 1C5, Québec, Canada; International Laboratory on Spine Imaging and Biomechanics (iLab-Spine), France.
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Beausejour MH, Petit Y, Arnoux PJ, Wagnac E. Comparison of Two Intervertebral Disc Failure Models in a Numerical C4-C5 Trauma Model .. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020; 2019:5415-5418. [PMID: 31947080 DOI: 10.1109/embc.2019.8857095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The intervertebral disc (IVD) is essential for the mobility and stability of the spine. During flexion-distraction injuries, which are frequent at the cervical spine level, the IVD is often disrupted. Finite element studies have been done to investigate injury mechanisms and patterns at the cervical spine. However, they rarely include IVD failure model. The aim of this paper was to implement and compare two types of IVD failure models and their impact on hyperflexion and hyperflexion-compression injuries simulations. The failure models were tested on a detailed C4-C5 finite elements model. The first failure model consisted in a maximal strain model applied to the elements of the annulus and nucleus. The second failure model consisted in the implementation of a rupture plane in the middle of the IVD with a tied interface created between the two sections. This interface is defined by threshold stress values of detachment in traction and shearing. The two failure models were tested in flexion only and in flexion-compression. The model without inclusion of an IVD failure model was also tested. Loads at failure and injury patterns were reported. Both failure models produce failure loads that were consistent with experimental data. Injury patterns observed were in agreement with experimental and numerical studies. However, in flexion-compression, the rupture plane model simulation reached important energy error due to high deformations in the IVD elements. Also, without inclusion of an IVD failure model, energy error forced the end of the simulation in flexion-compression. Therefore, inclusion of IVD failure model is important since it leads to realistic results, but the maximal strain failure model is recommended.
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Singh D, Cronin DS. An investigation of dimensional scaling using cervical spine motion segment finite element models. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2017; 33:e2872. [PMID: 28205412 DOI: 10.1002/cnm.2872] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Revised: 02/07/2017] [Accepted: 02/12/2017] [Indexed: 06/06/2023]
Abstract
The paucity of experimental data for validating computational models of different statures underscores the need for appropriate scaling methods so that models can be verified and validated using experimental data. Scaling was investigated using 50th percentile male (M50) and 5th percentile female (F05) cervical spine motion segment (C4-C5) finite element models subject to tension, flexion, and extension loading. Two approaches were undertaken: geometric scaling of the models to investigate size effects (volumetric scaling) and scaling of the force-displacement or moment-angle model results (data scaling). Three sets of scale factors were considered: global (body mass), regional (neck dimensions), and local (segment tissue dimensions). Volumetric scaling of the segment models from M50 to F05, and vice versa, produced correlations that were good or excellent in both tension and flexion (0.825-0.991); however, less agreement was found in extension (0.550-0.569). The reduced correlation in extension was attributed to variations in shape between the models leading to nonlinear effects such as different time to contact for the facet joints and posterior processes. Data scaling of the responses between the M50 and F05 models produced similar trends to volumetric scaling, with marginally greater correlations. Overall, the local tissue level and neck region level scale factors produced better correlations than the traditional global scaling. The scaling methods work well for a given subject, but are limited in applicability between subjects with different morphology, where nonlinear effects may dominate the response.
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Barker JB, Cronin DS, Nightingale RW. Lower Cervical Spine Motion Segment Computational Model Validation: Kinematic and Kinetic Response for Quasi-Static and Dynamic Loading. J Biomech Eng 2017; 139:2619324. [DOI: 10.1115/1.4036464] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Indexed: 12/28/2022]
Abstract
Advanced computational human body models (HBM) enabling enhanced safety require verification and validation at different levels or scales. Specifically, the motion segments, which are the building blocks of a detailed neck model, must be validated with representative experimental data to have confidence in segment and, ultimately, full neck model response. In this study, we introduce detailed finite element motion segment models and assess the models for quasi-static and dynamic loading scenarios. Finite element segment models at all levels in the lower human cervical spine were developed from scans of a 26-yr old male subject. Material properties were derived from the in vitro experimental data. The segment models were simulated in quasi-static loading in flexion, extension, lateral bending and axial rotation, and at dynamic rates in flexion and extension in comparison to previous experimental studies and new dynamic experimental data introduced in this study. Single-valued experimental data did not provide adequate information to assess the model biofidelity, while application of traditional corridor methods highlighted that data sets with higher variability could lead to an incorrect conclusion of improved model biofidelity. Data sets with continuous or multiple moment–rotation measurements enabled the use of cross-correlation for an objective assessment of the model and highlighted the importance of assessing all motion segments of the lower cervical spine to evaluate the model biofidelity. The presented new segment models of the lower cervical spine, assessed for range of motion and dynamic/traumatic loading scenarios, provide a foundation to construct a biofidelic model of the spine and neck, which can be used to understand and mitigate injury for improved human safety in the future.
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Affiliation(s)
- Jeffrey B. Barker
- Department of Mechatronics and Mechanical Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada e-mail:
| | - Duane S. Cronin
- Department of Mechatronics and Mechanical Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada
- Department of Mechanical Engineering, University of Waterloo, 200 University Avenue West, Waterloo, ON N2L 3G1, Canada e-mails:
| | - Roger W. Nightingale
- Division of Orthopaedic Surgery, Department of Biomedical Engineering, Duke University, Box 90281, Durham, NC 27708-0281 e-mail:
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