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Vogt M, Zengerle L, Jonas R, Wilke HJ. The move-C cervical artificial disc can restore intact range of motion and 3-D kinematics. Spine J 2024; 24:340-351. [PMID: 37660895 DOI: 10.1016/j.spinee.2023.08.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 08/15/2023] [Accepted: 08/29/2023] [Indexed: 09/05/2023]
Abstract
BACKGROUND CONTEXT In contrast to cervical discectomy and fusion, total disc replacement (TDR) aims at preserving the motion at the treated vertebral level. Spinal motion is commonly evaluated with the range of motion (ROM). However, more qualitative information about cervical kinematics before and after TDR is still lacking. PURPOSE The aim of this in vitro study was to investigate the influence of cervical TDR on ROM, instantaneous centers of rotation (ICR) and three-dimensional helical axes. STUDY DESIGN An in vitro study with human spine specimens under pure moment loading was conducted to evaluate the kinematics of the intact cervical spine and compare it to cervical TDR. METHODS Six fresh frozen human cervical specimens (C4-5, median age 28 years, range 19-47 years, two female and four male) were biomechanically characterized in the intact state and after implantation of a cervical disc prosthesis (MOVE-C, NGMedical, Germany). To mimic in vivo conditions regarding temperature and humidity, water steam was used to create a warm and humid test environment with 37°C. Each specimen was quasistatically loaded with pure moments up to ±2.5 Nm in flexion/extension (FE), lateral bending (LB) and axial rotation (AR) in a universal spine tester for 3.5 cycles at 1 °/s. For each third cycle of motion the ROM was evaluated and an established method was used to determine the helical axis and COR and to project them into three planar X-rays. Statistical analysis was conducted using a Friedman-test and post hoc correction with Dunn-Bonferroni-tests (p<.05). RESULTS After TDR, total ROM was increased in FE from 19.1° to 20.1°, decreased in LB from 14.6° to 12.6° and decreased in AR from 17.7° to 15.5°. No statistical differences between the primary ROM in the intact condition and ROM after TDR were detected. Coupled rotation between LB and AR were also maintained. The position and orientation of the helical axes after cervical TDR was in good agreement with the results of the intact specimens in all three motion directions. The ICR in FE and AR before and after TDR closely matched, while in LB the ICR after TDR were more caudal. The intact in vitro kinematics we found also resembled in vivo results of healthy individuals. CONCLUSION The results of this in vitro study highlight the potential of artificial cervical disc implants to replicate the quantity as well as the quality of motion of the intact cervical spine. CLINICAL SIGNIFICANCE Physiological motion preservation was a driving factor in the development of cervical TDR. Our results demonstrate the potential of cervical TDR to replicate in vivo kinematics in all three motion directions.
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Affiliation(s)
- Morten Vogt
- Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre Ulm, University of Ulm, Ulm, Germany
| | - Laura Zengerle
- Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre Ulm, University of Ulm, Ulm, Germany
| | - René Jonas
- Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre Ulm, University of Ulm, Ulm, Germany
| | - Hans-Joachim Wilke
- Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre Ulm, University of Ulm, Ulm, Germany.
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Hsieh MK, Tai CL, Li YD, Lee DM, Lin CY, Tsai TT, Lai PL, Chen WP. Finite element analysis of optimized novel additively manufactured non-articulating prostheses for cervical total disc replacement. Front Bioeng Biotechnol 2023; 11:1182265. [PMID: 37324423 PMCID: PMC10267663 DOI: 10.3389/fbioe.2023.1182265] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/22/2023] [Indexed: 06/17/2023] Open
Abstract
Ball-and-socket designs of cervical total disc replacement (TDR) have been popular in recent years despite the disadvantages of polyethylene wear, heterotrophic ossification, increased facet contact force, and implant subsidence. In this study, a non-articulating, additively manufactured hybrid TDR with an ultra-high molecular weight polyethylene core and polycarbonate urethane (PCU) fiber jacket, was designed to mimic the motion of normal discs. A finite element (FE) study was conducted to optimize the lattice structure and assess the biomechanical performance of this new generation TDR with an intact disc and a commercial ball-and-socket Baguera®C TDR (Spineart SA, Geneva, Switzerland) on an intact C5-6 cervical spinal model. The lattice structure of the PCU fiber was constructed using the Tesseract or the Cross structures from the IntraLattice model in the Rhino software (McNeel North America, Seattle, WA) to create the hybrid I and hybrid II groups, respectively. The circumferential area of the PCU fiber was divided into three regions (anterior, lateral and posterior), and the cellular structures were adjusted. Optimal cellular distributions and structures were A2L5P2 in the hybrid I and A2L7P3 in the hybrid II groups. All but one of the maximum von Mises stresses were within the yield strength of the PCU material. The range of motions, facet joint stress, C6 vertebral superior endplate stress and path of instantaneous center of rotation of the hybrid I and II groups were closer to those of the intact group than those of the Baguera®C group under 100 N follower load and pure moment of 1.5 Nm in four different planar motions. Restoration of normal cervical spinal kinematics and prevention of implant subsidence could be observed from the FE analysis results. Superior stress distribution in the PCU fiber and core in the hybrid II group revealed that the Cross lattice structure of a PCU fiber jacket could be a choice for a next-generation TDR. This promising outcome suggests the feasibility of implanting an additively manufactured multi-material artificial disc that allows for better physiological motion than the current ball-and-socket design.
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Affiliation(s)
- Ming-Kai Hsieh
- Department of Orthopaedic Surgery, Spine Section, Bone and Joint Research Center, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Ching-Lung Tai
- Department of Orthopaedic Surgery, Spine Section, Bone and Joint Research Center, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan
- Department of Biomedical Engineering, Chang Gung University, Taoyuan, Taiwan
| | - Yun-Da Li
- Department of Orthopaedic Surgery, Spine Section, Bone and Joint Research Center, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan
- Department of Biomedical Engineering, Chang Gung University, Taoyuan, Taiwan
| | - De-Mei Lee
- Department of Mechanical Engineering, Chang Gung University, Taoyuan, Taiwan
| | - Cheng-Yi Lin
- Department of Mechanical Engineering, National Taipei University of Technology, Taipei, Taiwan
| | - Tsung-Ting Tsai
- Department of Orthopaedic Surgery, Spine Section, Bone and Joint Research Center, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Po-Liang Lai
- Department of Orthopaedic Surgery, Spine Section, Bone and Joint Research Center, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Weng-Pin Chen
- Department of Mechanical Engineering, National Taipei University of Technology, Taipei, Taiwan
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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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Liu Z, Rong X, Liu H, Ding C, Hong Y, Wang B. Effect of Facet Tropism on Postoperative Cervical Range of Motion After Single-Level Cervical Disc Arthroplasty. Global Spine J 2022; 12:1696-1707. [PMID: 33511887 PMCID: PMC9609535 DOI: 10.1177/2192568220986144] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
STUDY DESIGN Retrospective analysis. OBJECTIVES Cervical disc arthroplasty (CDA) was designed to replace the degenerated disc with the prosthesis to preserve cervical motion. The commonly used artificial discs are designed symmetric, whereas the facet joints were reported to be asymmetric in many people. This study aimed to evaluate the effect of facet tropism on the cervical range of motion (ROM) after single-level CDA using Prestige LP. METHODS A total of 90 patients who underwent single-level CDA using Prestige LP from 2012 to 2017 were retrospectively reviewed. Radiographs were taken at each time point to measure the C2-C7 ROM and the ROM at the surgical segment. The pre-operation CT scans were utilized to reconstruct and calculate the angular direction of facet joints with respect to transverse, coronal, and sagittal reference planes. Facet tropism above 7° was defined as facet joint asymmetry. RESULTS No significant difference was found in flexion-extension C2-C7 ROM or ROM at the surgical segment between patients with symmetric and asymmetric fact joints regarding the sagittal plane. Patients with coronal asymmetric facet joints had lower flexion-extension ROM at the surgical level. Patients with transverse asymmetric facet joints had both lower flexion-extension C2-C7 ROM and ROM at the surgical level. After CDA surgery, patients obtained good clinical outcomes including increased Japanese Orthopedic Association (JOA) and decreased Neck Disability Index (NDI) as well as Visual Analogue Scale (VAS). CONCLUSION The coronal and transverse tropism seemed to be correlated with decreased flexion-extension ROM after CDA using Prestige LP.
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Affiliation(s)
- Ziyang Liu
- Department of Orthopedics, West China
Hospital, Sichuan University, Chengdu, Sichuan Province, China,Department of Orthopedics, Tianjin
Hospital, Tianjin Province, China
| | - Xin Rong
- Department of Orthopedics, West China
Hospital, Sichuan University, Chengdu, Sichuan Province, China
| | - Hao Liu
- Department of Orthopedics, West China
Hospital, Sichuan University, Chengdu, Sichuan Province, China,Hao Liu, Department of Orthopedic Surgery,
West China Hospital, No. 37, Guo Xue Xiang, Chengdu 610041, Sichuan Province,
China.
| | - Chen Ding
- Department of Orthopedics, West China
Hospital, Sichuan University, Chengdu, Sichuan Province, China
| | - Ying Hong
- Department of Operating Room, West China
Hospital, Sichuan University, Chengdu, Sichuan Province, China
| | - Beiyu Wang
- Department of Orthopedics, West China
Hospital, Sichuan University, Chengdu, Sichuan Province, China
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Burkhardt BW, Baumann L, Simgen A, Wagenpfeil G, Hendrix P, Reith W, Oertel JM. Long-term follow-up MRI shows no hastening of adjacent segment degeneration following cervical disc arthroplasty. Sci Rep 2022; 12:13318. [PMID: 35922473 PMCID: PMC9349281 DOI: 10.1038/s41598-022-17652-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 07/28/2022] [Indexed: 11/28/2022] Open
Abstract
Cervical disc arthroplasty is an established procedure, but studies with data on long-term clinical outcome, reoperation for symptomatic adjacent segment degeneration (sASD), and degenerative changes based on MRI findings are rare. Thus, a file review was performed and patients with complete documentation of neurological status at preoperative, postoperative, 12 month, 3–4 years follow-up including surgical reports for reoperation with a minimum follow-up of 9 years were included. Final follow-up assessment included a physical examination, assessment of pain levels, Odoms criteria, Neck disability index. The degeneration of each cervical segment at preoperative and at final follow-up was assessed using an MRI. Forty-six out of 68 included patients participated, the mean follow-up was 11 (range 9–15) years, at which 71.7% of patients were free of arm pain, 52.2% of patients were free of neck pain, 63% of patients had no sensory dysfunction, and full motor strength was noted in 95.6% of patients. The clinical success rate was 76.1%, the mean NDI was 12%. Overall repeated procedure rate was 17%, the reoperation rate for sASD was 9%, and removal of CDA was performed in 4%. MRI showed progressive degeneration but no significant changes of SDI from preoperative to final follow-up.
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Affiliation(s)
- Benedikt W Burkhardt
- Department of Neurosurgery, Saarland University Medical Center and Saarland University Faculty of Medicine, Homburg-Saar, Germany. .,Klinik für Neurochirurgie, Universitätsklinikum des Saarlandes und Medizinische Fakultät der Universität des Saarlandes, Kirrbergerstrasse 100, Gebäude 90.5, 66421, Homburg-Saar, Germany.
| | - Lukas Baumann
- Department of Neurosurgery, Saarland University Medical Center and Saarland University Faculty of Medicine, Homburg-Saar, Germany
| | - Andreas Simgen
- Department of Neuroradiology, Saarland University Medical Center and Saarland University Faculty of Medicine, Homburg-Saar, Germany
| | - Gudrun Wagenpfeil
- Institute for Medical Biometry, Epidemiology and Medical Informatics (IMBEI), Saarland University Faculty of Medicine, Homburg-Saar, Germany
| | - Philipp Hendrix
- Department of Neurosurgery, Saarland University Medical Center and Saarland University Faculty of Medicine, Homburg-Saar, Germany
| | - Wolfgang Reith
- Department of Neuroradiology, Saarland University Medical Center and Saarland University Faculty of Medicine, Homburg-Saar, Germany
| | - Joachim M Oertel
- Department of Neurosurgery, Saarland University Medical Center and Saarland University Faculty of Medicine, Homburg-Saar, Germany
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Li C, Yu X, Xiong Y, Yang Y, Wang F, Zhao H. Mid-long-term follow-up of operated level kinematics after single-level artificial cervical disc replacement with Bryan disc. J Orthop Surg Res 2022; 17:149. [PMID: 35264233 PMCID: PMC8905739 DOI: 10.1186/s13018-022-03051-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 03/02/2022] [Indexed: 11/10/2022] Open
Abstract
OBJECTIVE Evaluation of the mid-long-term kinematics of single-level Bryan artificial cervical disc replacement (ACDR) in vivo by analyzing the center of rotation (COR) at the operated level. METHODS A retrospective analysis was conducted using data collected from 38 patients who underwent single-level Bryan ACDR from January 2010 to March 2013. Radiological parameters including range of motion (ROM), lordosis angle, translation, and COR were obtained. Clinical outcomes were assessed based on Odom Criteria, modified Japanese Orthopedic Association (mJOA), Neck Disability Index (NDI), and Visual Analogue Scale (VAS) scores. Correlations between COR and other follow-up data were discussed at the last follow-up. RESULTS Compared with preoperative values, the last follow-up data showed that 86.84% of cases achieved good-or-excellent outcomes based on Odom criteria; Significant improvements were observed across all scales assessed for clinical outcomes (P < 0.05); Lordosis angle was significantly increased in both the overall cervical spine and the operated level (P < 0.05); ROM of the overall cervical spine, operated level, and adjacent levels was preserved (P > 0.05); There was no significant change in COR at the operated level (P > 0.05). At the last follow-up and at the operated level, COR (Y) showed negative correlations with ROM and translation (P < 0.05), but no follow-up data correlated with COR (X) were found (P > 0.05). CONCLUSIONS Satisfactory clinical and radiological outcomes were achieved 7 years or more after single-level Bryan ACDR. At the operated level, preoperative COR was maintained, probably due to replicating the physiological interrelations of COR (Y), translation, and ROM.
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Affiliation(s)
- Chuanhong Li
- Department of Orthopedics, Dongzhimen Hospital, Beijing University of Chinese Medicine, No. 5 Haiyuncang Street, Dongcheng District, Beijing, 100700, China
| | - Xing Yu
- Department of Orthopedics, Dongzhimen Hospital, Beijing University of Chinese Medicine, No. 5 Haiyuncang Street, Dongcheng District, Beijing, 100700, China.
| | - Yang Xiong
- School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, China
| | - Yongdong Yang
- Department of Orthopedics, Dongzhimen Hospital, Beijing University of Chinese Medicine, No. 5 Haiyuncang Street, Dongcheng District, Beijing, 100700, China
| | - Fengxian Wang
- Department of Orthopedics, Dongzhimen Hospital, Beijing University of Chinese Medicine, No. 5 Haiyuncang Street, Dongcheng District, Beijing, 100700, China
| | - He Zhao
- Department of Orthopedics, Dongzhimen Hospital, Beijing University of Chinese Medicine, No. 5 Haiyuncang Street, Dongcheng District, Beijing, 100700, China
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Muhlbauer MK, Tomasch E, Sinz W, Trattnig S, Steffan H. Cervical disc prostheses need a variable center of rotation for flexion / extension below disc level, plus a separate COR for lateral bending above disc level to more closely replicate in-vivo motion: MRI-based biomechanical in-vivo study. BMC Musculoskelet Disord 2022; 23:227. [PMID: 35260131 PMCID: PMC8905756 DOI: 10.1186/s12891-022-05121-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 02/09/2022] [Indexed: 11/24/2022] Open
Abstract
Background Cervical disc prostheses are used to preserve motion after discectomy, but they should also provide a near-physiological qualitative motion pattern. Nevertheless, they come in many completely different biomechanical concepts. This caused us to perform an in-vivo MR-based biomechanical study to further investigate cervical spine motion with the aim to gain new information for improving the design of future cervical arthroplasty devices. Methods Fifteen healthy volunteers underwent MRI-investigation (in order to avoid radiation exposure) of their cervical spines from C3 to C7; for each segment centers of rotation (COR) for flexion / extension were determined from 5 different positions, and CORs for lateral bending from 3 different positions. The motion path of the COR is then described and illustrated in relation to the respective COR for maximum flexion / extension or lateral bending, respectively, and the findings are translated into implications for a better biomechanical prosthesis-design. Results The COR for flexion / extension does not remain constant during motion. The CORs for the respective motion intervals were always found at different positions than the COR for maximum flexion /extension showing that the COR moves both along the x- and the y-axis throughout flexion / extension. For lateral bending a completely independent COR was found above disc-level. Conclusion Flexion / extension is not a simple circular motion. Disc prostheses need a variable COR for flexion / extension below disc level with the capability to move both along the x- and the y-axis during motion, plus a second completely independent COR for lateral bending above disc level to closely replicate in-vivo motion. These findings are important for improving the biomechanical design of such devices in the future.
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Affiliation(s)
- Manfred K Muhlbauer
- Neurosurgical Department, Klinik Donaustadt, Langobardenstrasse 122, 1220, Vienna, Austria.
| | - Ernst Tomasch
- Vehicle Safety Institute, Graz University of Technology, Graz, Austria
| | - Wolfgang Sinz
- Vehicle Safety Institute, Graz University of Technology, Graz, Austria
| | - Siegfried Trattnig
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Hermann Steffan
- Vehicle Safety Institute, Graz University of Technology, Graz, Austria
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Lindenmann S, Tsagkaris C, Farshad M, Widmer J. Kinematics of the Cervical Spine Under Healthy and Degenerative Conditions: A Systematic Review. Ann Biomed Eng 2022; 50:1705-1733. [PMID: 36496482 PMCID: PMC9794546 DOI: 10.1007/s10439-022-03088-8] [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: 06/15/2022] [Accepted: 09/20/2022] [Indexed: 12/14/2022]
Abstract
Knowledge of spinal kinematics is essential for the diagnosis and management of spinal diseases. Distinguishing between physiological and pathological motion patterns can help diagnose these diseases, plan surgical interventions and improve relevant tools and software. During the last decades, numerous studies based on diverse methodologies attempted to elucidate spinal mobility in different planes of motion. The authors aimed to summarize and compare the evidence about cervical spine kinematics under healthy and degenerative conditions. This includes an illustrated description of the spectrum of physiological cervical spine kinematics, followed by a comparable presentation of kinematics of the degenerative cervical spine. Data was obtained through a systematic MEDLINE search including studies on angular/translational segmental motion contribution, range of motion, coupling and center of rotation. As far as the degenerative conditions are concerned, kinematic data regarding disc degeneration and spondylolisthesis were available. Although the majority of the studies identified repeating motion patterns for most motion planes, discrepancies associated with limited sample sizes and different imaging techniques and/or spine configurations, were noted. Among healthy/asymptomatic individuals, flexion extension (FE) and lateral bending (LB) are mainly facilitated by the subaxial cervical spine. C4-C5 and C5-C6 were the major FE contributors in the reported studies, exceeding the motion contribution of sub-adjacent segments. Axial rotation (AR) greatly depends on C1-C2. FE range of motion (ROM) is distributed between the atlantoaxial and subaxial segments, while AR ROM stems mainly from the former and LB ROM from the latter. In coupled motion rotation is quantitatively predominant over translation. Motion migrates caudally from C1-C2 and the center of rotation (COR) translocates anteriorly and superiorly for each successive subaxial segment. In degenerative settings, concurrent or subsequent lesions render the association between diseases and mobility alterations challenging. The affected segments seem to maintain translational and angular motion in early and moderate degeneration. However, the progression of degeneration restrains mobility, which seems to be maintained or compensated by adjacent non-affected segments. While the kinematics of the healthy cervical spine have been addressed by multiple studies, the entire nosological and kinematic spectrum of cervical spine degeneration is partially addressed. Large-scale in vivo studies can complement the existing evidence, cover the gaps and pave the way to technological and clinical breakthroughs.
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Affiliation(s)
- Sara Lindenmann
- Spine Biomechanics, Department of Orthopaedics, Balgrist University Hospital, Zurich, Switzerland
| | - Christos Tsagkaris
- Spine Biomechanics, Department of Orthopaedics, Balgrist University Hospital, Zurich, Switzerland ,Department of Orthopaedics, Balgrist University Hospital, Forchstrasse 340, 8008 Zurich, Switzerland
| | - Mazda Farshad
- Spine Biomechanics, Department of Orthopaedics, Balgrist University Hospital, Zurich, Switzerland
| | - Jonas Widmer
- Department of Orthopaedics, Balgrist University Hospital, Forchstrasse 340, 8008 Zurich, Switzerland
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Affiliation(s)
- Elie Massaad
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Ali Kiapour
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - John H Shin
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
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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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Muhlbauer M, Tomasch E, Sinz W, Trattnig S, Steffan H. Correction to: In cervical arthroplasty, only prosthesis with flexible biomechanical properties should be used for achieving a near-physiological motion pattern. J Orthop Surg Res 2020; 15:565. [PMID: 33243263 PMCID: PMC7694289 DOI: 10.1186/s13018-020-02110-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
An amendment to this paper has been published and can be accessed via the original article.
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Affiliation(s)
- Manfred Muhlbauer
- Neurosurgical Department, Donauspital SMZ-Ost, Langobardenstrasse 122, 1220, Vienna, Austria.
| | - Ernst Tomasch
- Vehicle Safety Institute, Graz University of Technology, Graz, Austria
| | - Wolfgang Sinz
- Vehicle Safety Institute, Graz University of Technology, Graz, Austria
| | - Siegfried Trattnig
- High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria
| | - Hermann Steffan
- Vehicle Safety Institute, Graz University of Technology, Graz, Austria
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