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Henriques D, Martins AP, Carvalho MS. Efficient 2D Neck Model for Simulation of the Whiplash Injury Mechanism. Bioengineering (Basel) 2024; 11:129. [PMID: 38391615 PMCID: PMC11154333 DOI: 10.3390/bioengineering11020129] [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: 11/07/2023] [Revised: 01/11/2024] [Accepted: 01/24/2024] [Indexed: 02/24/2024] Open
Abstract
Whiplash injuries, mainly located in the neck, are one of the most common injuries resulting from road collisions. These injuries can be particularly challenging to detect, compromising the ability to monitor patients adequately. This work presents the development and validation of a computationally efficient model, called Efficient Neck Model-2D (ENM-2D), capable of simulating the whiplash injury mechanism. ENM-2D is a planar multibody model consisting of several bodies that model the head and neck with the same mass and inertia properties of a male occupant model in the 50th percentile. The damping and non-linear spring parameters of the kinematic joints were identified through a multiobjective optimization process, solved sequentially. The TNO-Human Body Model (TNO-HBM), a validated occupant model for rear impact, was simulated, and its responses were used as a reference for validation purposes. The root mean square (RMS) of the deviations of angular positions of the bodies were used as objective functions, starting from the bottom vertebra to the top, and ending in the head. The sequence was repeated until it converged, ending the optimization process. The identified ENM-2D model could simulate the whiplash injury mechanism kinematics and accurately determine the injury criteria associated with head and neck injuries. It had a relative deviation of 8.3% for the head injury criteria and was 12.5 times faster than the reference model.
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Affiliation(s)
- Diamantino Henriques
- UNIDEMI, Department of Mechanical and Industrial Engineering, NOVA School of Science and Technology, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal; (D.H.); (A.P.M.)
| | - Ana P. Martins
- UNIDEMI, Department of Mechanical and Industrial Engineering, NOVA School of Science and Technology, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal; (D.H.); (A.P.M.)
| | - Marta S. Carvalho
- UNIDEMI, Department of Mechanical and Industrial Engineering, NOVA School of Science and Technology, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal; (D.H.); (A.P.M.)
- Laboratório Associado de Sistemas Inteligentes, LASI, 4800-058 Guimarães, Portugal
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Vedantam A, Harinathan B, Purushothaman Y, Scripp S, Banerjee A, Warraich A, Budde MD, Yoganandan N. Determinants of spinal cord stress and strain in degenerative cervical myelopathy: a patient-specific finite element study. Biomech Model Mechanobiol 2023; 22:1789-1799. [PMID: 37306885 DOI: 10.1007/s10237-023-01732-3] [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: 01/21/2023] [Accepted: 05/29/2023] [Indexed: 06/13/2023]
Abstract
Degenerative cervical myelopathy (DCM) is the commonest cause of spinal cord dysfunction in older adults and is characterized by chronic cervical spinal cord compression. Spinal cord stress and strain during neck motion are also known contributors to the pathophysiology of DCM, yet these factors are not routinely assessed for surgical planning. The aim of this study was to measure spinal cord stress/strain in DCM using patient-specific 3D finite element models (FEMs) and determine whether spinal cord compression is the primary determinant of spinal cord stress/strain. Three-dimensional patient-specific FEMs were created for six DCM patients (mild [n = 2], moderate [n = 2] and severe [n = 2]). Flexion and extension of the cervical spine were simulated with a pure moment load of 2 Nm. Segmental spinal cord von Mises stress and maximum principal strain were measured. Measures of spinal cord compression and segmental range of motion (ROM) were included in a regression analysis to determine associations with spinal cord stress and strain. Segmental ROM in flexion-extension and axial rotation was independently associated with spinal cord stress (p < 0.001) and strain (p < 0.001), respectively. This relationship was not seen for lateral bending. Segmental ROM had a stronger association with spinal stress and strain as compared to spinal cord compression. Compared to the severity of spinal cord compression, segmental ROM is a stronger determinant spinal cord stress and strain. Surgical procedures that address segmental ROM in addition to cord compression may best optimize spinal cord biomechanics in DCM.
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Affiliation(s)
- Aditya Vedantam
- Department of Neurosurgery, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA.
| | - Balaji Harinathan
- Department of Neurosurgery, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
| | - Yuvaraj Purushothaman
- Department of Neurosurgery, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
| | - Stephen Scripp
- Biomedical Engineering, Milwaukee School of Engineering, Milwaukee, WI, USA
| | - Anjishnu Banerjee
- Department of Biostatistics, Medical College of Wisconsin, Milwaukee, WI, USA
| | - Ali Warraich
- Department of Chemistry, University of Chicago, Chicago, IL, USA
| | - Matthew D Budde
- Department of Neurosurgery, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
| | - Narayan Yoganandan
- Department of Neurosurgery, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA
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Yordanov S, Yang X, Mowforth O, K Demetriades A, Ivanov M, Vergara P, Gardner A, Pereira E, Bateman A, Alamri A, Francis J, Trivedi R, Kotter M, Davies B, Budu A. Factors Influencing Surgical Decision-Making in the Posterior Laminectomy With Fixation for Degenerative Cervical Myelopathy (POLYFIX-DCM) Trial: Survey Study. JMIR Form Res 2023; 7:e48321. [PMID: 37698903 PMCID: PMC10523224 DOI: 10.2196/48321] [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: 04/19/2023] [Revised: 06/12/2023] [Accepted: 06/30/2023] [Indexed: 09/13/2023] Open
Abstract
BACKGROUND Degenerative cervical myelopathy (DCM) is estimated to affect 2% of the adult population. DCM occurs when degenerative processes cause compression and injure the spinal cord. Surgery to remove the stress caused by the compression of the spinal cord is the mainstay of treatment, with a range of techniques in use. Although various factors are described to inform the selection of these techniques, there needs to be more consensus and limited comparative evidence. OBJECTIVE The main objective of this survey was to explore the variation of practice and decision-making, with a focus on laminectomy versus laminectomy and fusion in posterior surgery of the cervical spine. We present the results of a survey conducted among the principal investigators (PIs) of the National Institute for Health and Care Research (NIHR) randomized controlled trial on posterior laminectomy with fixation for degenerative cervical myelopathy (POLYFIX-DCM). METHODS A series of 7 cases were shared with 24 PIs using SurveyMonkey. Each case consisted of a midsagittal T2-weighted magnetic resonance imaging and lateral cervical x-rays in flexion and extension. Surgeons were asked if their preferred approach was anterior or posterior. If posterior, they were asked whether they preferred to instrument and whether they had the equipoise to randomize in the NIHR POLYFIX-DCM trial. Variability in decision-making was then explored using factors reported to inform decision-making, such as alignment, location of compression, number of levels operated, presence of mobile spondylolisthesis, and patient age. RESULTS The majority of PIs (16/30, 53%) completed the survey. Overall, PIs favored a posterior approach (12/16, 75%) with instrumentation (75/112, average 66%) and would randomize (67/112, average 62%) most cases. Factors reported to inform decision-making poorly explained variability in responses in both univariate testing and with a multivariate model (R2=0.1). Only surgeon experience of more than 5 years and orthopedic specialty training background were significant predictors, both associated with an anterior approach (odds ratio [OR] 1.255; P=.02 and OR 1.344; P=.007, respectively) and fusion for posterior procedures (OR 0.628; P<.001 and OR 1.344; P<.001, respectively). Surgeon experience also significantly affected the openness to randomize, with those with more than 5 years of experience less likely to randomize (OR -0.68; P<.001). CONCLUSIONS In this representative sample of spine surgeons participating in the POLYFIX-DCM trial as investigators, there is no consensus on surgical strategy, including the role of instrumented fusion following posterior decompression. Overall, this study supports the view that there appears to be a clinical equipoise, and conceptually, a randomized controlled trial appears feasible, which sets the scene for the NIHR POLYFIX-DCM trial.
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Affiliation(s)
- Stefan Yordanov
- Academic Neurosurgery Unit, Department of Clinical Neurosurgery, Cambridge University, Cambridge, United Kingdom
| | - Xiaoyu Yang
- Academic Neurosurgery Unit, Department of Clinical Neurosurgery, Cambridge University, Cambridge, United Kingdom
| | - Oliver Mowforth
- Academic Neurosurgery Unit, Department of Clinical Neurosurgery, Cambridge University, Cambridge, United Kingdom
| | | | - Marcel Ivanov
- Neurosurgery Department, Royal Hallamshire Hospital, Sheffield, United Kingdom
| | - Pierluigi Vergara
- Department of Spinal Surgery, East Suffolk and North Essex NHS Foundation Trust, Ipswich, United Kingdom
| | - Adrian Gardner
- The Royal Orthopaedic Hospital NHS Foundation Trust, Birmingham, United Kingdom
| | - Erlick Pereira
- Department of Neurosurgery, St Georges University Hospital NHS Foundation Trust, London, United Kingdom
| | - Antony Bateman
- Royal Derby Spinal Centre, University Hospitals of Derby and Burton NHS Foundation Trust, Derby, United Kingdom
| | - Alexander Alamri
- Department of Neurosurgery, St Georges University Hospital NHS Foundation Trust, London, United Kingdom
| | - Jibin Francis
- Academic Neurosurgery Unit, Department of Clinical Neurosurgery, Cambridge University, Cambridge, United Kingdom
| | - Rikin Trivedi
- Academic Neurosurgery Unit, Department of Clinical Neurosurgery, Cambridge University, Cambridge, United Kingdom
| | - Mark Kotter
- Academic Neurosurgery Unit, Department of Clinical Neurosurgery, Cambridge University, Cambridge, United Kingdom
| | - Benjamin Davies
- Academic Neurosurgery Unit, Department of Clinical Neurosurgery, Cambridge University, Cambridge, United Kingdom
| | - Alexandru Budu
- Department of Neurosurgery, Queen Elizabeth Hospital, Birmingham, United Kingdom
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Singhal I, Harinathan B, Warraich A, Purushothaman Y, Budde MD, Yoganandan N, Vedantam A. Finite element modeling of the human cervical spinal cord and its applications: A systematic review. NORTH AMERICAN SPINE SOCIETY JOURNAL 2023; 15:100246. [PMID: 37636342 PMCID: PMC10448221 DOI: 10.1016/j.xnsj.2023.100246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/01/2023] [Accepted: 07/23/2023] [Indexed: 08/29/2023]
Abstract
Background Context Finite element modeling (FEM) is an established tool to analyze the biomechanics of complex systems. Advances in computational techniques have led to the increasing use of spinal cord FEMs to study cervical spinal cord pathology. There is considerable variability in the creation of cervical spinal cord FEMs and to date there has been no systematic review of the technique. The aim of this study was to review the uses, techniques, limitations, and applications of FEMs of the human cervical spinal cord. Methods A literature search was performed through PubMed and Scopus using the words finite element analysis, spinal cord, and biomechanics. Studies were selected based on the following inclusion criteria: (1) use of human spinal cord modeling at the cervical level; (2) model the cervical spinal cord with or without the osteoligamentous spine; and (3) the study should describe an application of the spinal cord FEM. Results Our search resulted in 369 total publications, 49 underwent reviews of the abstract and full text, and 23 were included in the study. Spinal cord FEMs are used to study spinal cord injury and trauma, pathologic processes, and spine surgery. Considerable variation exists in the derivation of spinal cord geometries, mathematical models, and material properties. Less than 50% of the FEMs incorporate the dura mater, cerebrospinal fluid, nerve roots, and denticulate ligaments. Von Mises stress, and strain of the spinal cord are the most common outputs studied. FEM offers the opportunity for dynamic simulation, but this has been used in only four studies. Conclusions Spinal cord FEM provides unique insight into the stress and strain of the cervical spinal cord in various pathological conditions and allows for the simulation of surgical procedures. Standardization of modeling parameters, anatomical structures and inclusion of patient-specific data are necessary to improve the clinical translation.
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Affiliation(s)
- Ishan Singhal
- Department of Neurosurgery, Medical College of Wisconsin, 9200 W Wisconsin Ave, Milwaukee, WI 53226, United States
| | - Balaji Harinathan
- Department of Neurosurgery, Medical College of Wisconsin, 9200 W Wisconsin Ave, Milwaukee, WI 53226, United States
| | - Ali Warraich
- University of Chicago, 1413 East 57 St, Chicago, IL 60637, United States
| | - Yuvaraj Purushothaman
- Department of Neurosurgery, Medical College of Wisconsin, 9200 W Wisconsin Ave, Milwaukee, WI 53226, United States
| | - Matthew D. Budde
- Department of Neurosurgery, Medical College of Wisconsin, 9200 W Wisconsin Ave, Milwaukee, WI 53226, United States
| | - Narayan Yoganandan
- Department of Neurosurgery, Medical College of Wisconsin, 9200 W Wisconsin Ave, Milwaukee, WI 53226, United States
| | - Aditya Vedantam
- Department of Neurosurgery, Medical College of Wisconsin, 9200 W Wisconsin Ave, Milwaukee, WI 53226, United States
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Lin D, He Z, Weng R, Zhu Y, Lin Z, Deng Y, Yang Y, Tan J, Wang M, Li Y, Huang G, Yu G, Cai D, Huang X, Huang W. Comparison of biomechanical parameters of two Chinese cervical spine rotation manipulations based on motion capture and finite element analysis. Front Bioeng Biotechnol 2023; 11:1195583. [PMID: 37576989 PMCID: PMC10415076 DOI: 10.3389/fbioe.2023.1195583] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 07/20/2023] [Indexed: 08/15/2023] Open
Abstract
Objective: The purpose of this study was to obtain the stress-strain of the cervical spine structure during the simulated manipulation of the oblique pulling manipulation and the cervical rotation-traction manipulation in order to compare the mechanical mechanism of the two manipulations. Methods: A motion capture system was used to record the key kinematic parameters of operating the two manipulations. At the same time, a three-dimensional finite element model of the C0-T1 full healthy cervical spine was established, and the key kinematic parameters were loaded onto the finite element model in steps to analyze and simulate the detailed process of the operation of the two manipulations. Results: A detailed finite element model of the whole cervical spine including spinal nerve roots was established, and the validity of this 3D finite element model was verified. During the stepwise simulation of the two cervical spine rotation manipulations to the right, the disc (including the annulus fibrosus and nucleus pulposus) and facet joints stresses and displacements were greater in the oblique pulling manipulation group than in the cervical rotation-traction manipulation group, while the spinal cord and nerve root stresses were greater in the cervical rotation-traction manipulation group than in the oblique pulling manipulation group. The spinal cord and nerve root stresses in the cervical rotation-traction manipulation group were mainly concentrated in the C4/5 and C5/6 segments. Conclusion: The oblique pulling manipulation may be more appropriate for the treatment of cervical spondylotic radiculopathy, while cervical rotation-traction manipulation is more appropriate for the treatment of cervical spondylosis of cervical type. Clinicians should select cervical rotation manipulations for different types of cervical spondylosis according to the patient's symptoms and needs.
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Affiliation(s)
- Dongxin Lin
- Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, Guangdong Provincial Key Laboratory of Medical Biomechanics, National Key Discipline of Human Anatomy, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Zaopeng He
- Center for Orthopaedic Surgery, Department of Orthopedics, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
- The Third School of Clinical Medicine, Southern Medical University, Guangzhou, China
- Department of Hand and Foot Surgery and Plastic Surgery, Affiliated Shunde Hospital of Guangzhou Medical University, Foshan, China
| | - Rui Weng
- The Third Affiliated Hospital of Guangzhou University of Chinese Medicine, Guangzhou, China
- Guangdong Research Institute for Orthopedics and Traumatology of Chinese Medicine, Guangzhou, China
| | - Yuhua Zhu
- Department of Spinal Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Zhiwei Lin
- Orthopedic Center, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
- Department of Human Anatomy and Histoembryology, School of Basic Medical Sciences, Guangdong Medical University, Dongguan, China
| | - Yuping Deng
- Department of Orthopedics and Traumatology, Integrated Hospital of Traditional Chinese Medicine, Southern Medical University, Guangzhou, China
- Institute of Biomedical Engineering, Shenzhen Bay Laboratory, Shenzhen, China
| | - Yang Yang
- Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, Guangdong Provincial Key Laboratory of Medical Biomechanics, National Key Discipline of Human Anatomy, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Jinchuan Tan
- Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, Guangdong Provincial Key Laboratory of Medical Biomechanics, National Key Discipline of Human Anatomy, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Mian Wang
- Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, Guangdong Provincial Key Laboratory of Medical Biomechanics, National Key Discipline of Human Anatomy, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Yanbin Li
- Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, Guangdong Provincial Key Laboratory of Medical Biomechanics, National Key Discipline of Human Anatomy, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Gang Huang
- Department of Orthopedics and Traumatology, Integrated Hospital of Traditional Chinese Medicine, Southern Medical University, Guangzhou, China
| | - Guanghao Yu
- Mudanjiang Medical University, Mudanjiang, Heilongjiang, China
| | - Daozhang Cai
- Center for Orthopaedic Surgery, Department of Orthopedics, The Third Affiliated Hospital of Southern Medical University, Guangzhou, China
- The Third School of Clinical Medicine, Southern Medical University, Guangzhou, China
- Orthopedic Hospital of Guangdong Province, Academy of Orthopedics, Guangzhou, China
| | - Xuecheng Huang
- Shenzhen Hospital of Guangzhou University of Chinese Medicine (Futian), Shenzhen, China
| | - Wenhua Huang
- Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, Guangdong Provincial Key Laboratory of Medical Biomechanics, National Key Discipline of Human Anatomy, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
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Vedantam A, Purushothaman Y, Harinathan B, Scripp S, Budde MD, Yoganandan N. Spinal Cord Stress After Anterior Cervical Diskectomy and Fusion: Results from a Patient-Specific Finite Element Model. Ann Biomed Eng 2022; 51:1040-1051. [PMID: 36538274 DOI: 10.1007/s10439-022-03118-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 12/12/2022] [Indexed: 12/24/2022]
Abstract
Degenerative cervical myelopathy (DCM) is the commonest cause of cervical spinal cord dysfunction in older adults and is characterized by spinal cord compression and stress during neck motion. Although surgical decompression eliminates static spinal cord compression, cord stress resulting from flexion-extension motion of the spinal column has not been determined for single and multi-level surgical interventions. The effect of surgery on spinal cord stress is expected to change with the number of surgical levels as well as patient-specific anatomy. Using a MRI-derived patient-specific finite element model, we simulated 1-, 2- and 3-level anterior cervical diskectomy and fusion (ACDF) surgery for DCM. A substantial decrease in spinal cord stress at the level of spinal cord decompression was noted in all simulations. This was associated with a considerable increase in spinal cord stress rostral to the surgical level, and the magnitude of stress was higher in multi-level surgery. Increased spinal cord stress at the rostral adjacent segment correlated with increased segmental range of motion (r = 0.69, p = 0.002) and disk pressure (r = 0.57, p = 0.05). Together, these results indicate that ACDF for DCM is associated with adverse spinal cord stress patterns adjacent to the fusion construct, and further research is needed to determine if the altered stress is associated with clinical outcomes after surgery for DCM.
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