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Lin Z, Lin D, Xu L, Chen Q, Vashisth MK, Huang X, Deng Y, Zhang F, Huang W. Biomechanical evaluation on a new type of vertebral titanium porous mini-plate and mechanical comparison between cervical open-door laminoplasty and laminectomy: a finite element analysis. Front Bioeng Biotechnol 2024; 12:1353797. [PMID: 38375455 PMCID: PMC10875091 DOI: 10.3389/fbioe.2024.1353797] [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: 12/11/2023] [Accepted: 01/22/2024] [Indexed: 02/21/2024] Open
Abstract
Objective: Compare the spine's stability after laminectomy (LN) and laminoplasty (LP) for two posterior surgeries. Simultaneously, design a new vertebral titanium porous mini plate (TPMP) to achieve firm fixation of the open-door vertebral LP fully. The objective is to enhance the fixation stability, effectively prevent the possibility of "re-closure," and may facilitate bone healing. Methods: TPMP was designed by incorporating a fusion body and porous structures, and a three-dimensional finite element cervical model of C2-T1 was constructed and validated. Load LN and LP finite element models, respectively, and analyze and simulate the detailed processes of the two surgeries. It was simultaneously implanting the TPMP into LP to evaluate its biomechanical properties. Results: We find that the range of motion (ROM) of C4-C5 after LN surgery was greater than that of LP implanted with different plates alone. Furthermore, flexion-extension, lateral bending, and axial rotation reflect this change. More noteworthy is that LN has a much larger ROM on C2-C3 in axial rotation. The ROM of LP implanted with two different plates is similar. There is almost no difference in facet joint stress in lateral bending. The facet joint stress of LN is smaller on C2-C3 and C4-C5, and larger more prominent on C5-C6 in the flexion-extension. Regarding intervertebral disc pressure (IDP), there is little difference between different surgeries except for the LN on C2-C3 in axial rotation. The plate displacement specificity does not significantly differ from LP with vertebral titanium mini-plate (TMP) and LP with TPMP after surgery. The stress of LP with TPMP is larger in C4-C5, C5-C6. Moreover, LP with TMP shows greater stress in the C3-C4 during flexion-extension and lateral bending. Conclusion: LP may have better postoperative stability when posterior approach surgery is used to treat CSM; at the same time, the new type of vertebral titanium mini-plate can achieve almost the same effect as the traditional titanium mini-plate after surgery for LP. In addition, it has specific potential due to the porous structure promoting bone fusion.
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Affiliation(s)
- Zhiwei Lin
- School of Basic Medical Sciences, Guangdong Medical University, Dongguan, China
| | - Dongxin Lin
- Guangdong Provincial Key Laboratory of Digital Medicine and Biomechanics, National Key Discipline of Human Anatomy, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Lin Xu
- Guangdong Provincial Key Laboratory of Digital Medicine and Biomechanics, National Key Discipline of Human Anatomy, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
- Department of Orthopaedic, The First Hospital of Qiqihar, Heilongjiang, China
| | - Qiwei Chen
- Guangdong Provincial Key Laboratory of Digital Medicine and Biomechanics, National Key Discipline of Human Anatomy, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Manoj Kumar Vashisth
- Guangdong Provincial Key Laboratory of Digital Medicine and Biomechanics, National Key Discipline of Human Anatomy, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
| | - Xuecheng Huang
- Shenzhen Hospital of Guangzhou University of Chinese Medicine (Futian), Shenzhen, China
| | - Yuping Deng
- Integrated Hospital of Traditional Chinese Medicine, Southern Medical University, Guangzhou, China
| | - Feihu Zhang
- School of Basic Medical Sciences, Guangdong Medical University, Dongguan, China
| | - Wenhua Huang
- School of Basic Medical Sciences, Guangdong Medical University, Dongguan, China
- Guangdong Provincial Key Laboratory of Digital Medicine and Biomechanics, National Key Discipline of Human Anatomy, Guangdong Engineering Research Center for Translation of Medical 3D Printing Application, School of Basic Medical Sciences, Southern Medical University, Guangzhou, China
- Department of Orthopaedic, The First Hospital of Qiqihar, Heilongjiang, China
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Zavras AG, Federico VP, Butler AJ, Nolte MT, Dandu N, Phillips FM, Colman MW. Relative Efficacy of Cervical Total Disc Arthroplasty Devices and Anterior Cervical Discectomy and Fusion for Cervical Pathology: A Network Meta-Analysis. Global Spine J 2024; 14:322-346. [PMID: 37099726 PMCID: PMC10676167 DOI: 10.1177/21925682231172982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/28/2023] Open
Abstract
STUDY DESIGN Systematic Review and Meta Analysis. OBJECTIVE This study sought to compare patient-reported outcomes, success, complications, and radiographic outcomes directly and indirectly between different cervical total disc arthroplasty (TDA) devices and anterior cervical discectomy and fusion (ACDF). METHODS Patients of prospective randomized controlled trials of 1-level cervical TDA with a minimum of 2 years follow up were identified in the literature. A frequentist network meta-analysis model was used to compare each outcome across the different TDA devices included and ACDF using the mixed effect sizes. RESULTS 15 studies were included for quantitative analysis, reporting the outcomes of 2643 patients with an average follow-up was 67.3 months (range: 24-120 months), 1417 of whom underwent TDA and 1226 of whom underwent ACDF. Nine TDA devices were compared to ACDF, including the Bryan, Discover, Kineflex, M6, Mobi-C, PCM, Prestige ST, ProDisc-C, and Secure-C cervical prostheses. Several devices outperformed ACDF for certain outcomes, including Visual Analog Scale (VAS) Arm, Physical Component Score of the Short-Form Health Survey (SF PCS), neurological success, satisfaction, index-level secondary surgical interventions (SSI), and adjacent level surgeries. Cumulative ranking of each intervention assessed demonstrated the highest performance with the M6 prosthesis (P = .70), followed by Secure-C (P = .67), PCM (P = .57), Prestige ST (P = .57), ProDisc-C (P = .54), Mobi-C (P = .53), Bryan (P = .49), Kineflex (P = .49), Discover (P = .39), and ACDF (P = .14). CONCLUSION Cervical TDA was found to be superior on most outcomes assessed in the literature of high-quality clinical trials. While most devices demonstrated similar outcomes, certain prostheses such as the M6 were found to outperform others across several outcomes assessed. These findings suggest that the restoration of near-normal cervical kinematics may lead to improved outcomes.
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Affiliation(s)
- Athan G. Zavras
- Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, USA
| | - Vincent P. Federico
- Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, USA
| | - Alexander J. Butler
- Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, USA
| | - Michael T. Nolte
- Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, USA
| | - Navya Dandu
- Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, USA
| | - Frank M. Phillips
- Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, USA
| | - Matthew W. Colman
- Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, USA
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Lanman TH, Cuellar JM, Mottole N, Wernke M, Carruthers E, Valdevit A. Range of motion after 1, 2, and 3 level cervical disc arthroplasty. NORTH AMERICAN SPINE SOCIETY JOURNAL 2023; 16:100294. [PMID: 38162168 PMCID: PMC10755821 DOI: 10.1016/j.xnsj.2023.100294] [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: 08/25/2023] [Revised: 11/16/2023] [Accepted: 11/17/2023] [Indexed: 01/03/2024]
Abstract
Background Motion of a solid body involves translation and rotation. Few investigations examine the isolated translational and rotational components associated with disc arthroplasty devices. This study investigates single- and multi-level cervical disc arthroplasty with respect to index and adjacent level range of motion. The investigators hypothesized that single- and multilevel cervical disc replacement will lead to comparable or improved motion at implanted and adjacent levels. Methods Seven human cervical spines from C2 to C7 were subjected to displacement-controlled loading in flexion, extension, and lateral bending under intact, 1-Level (C5-C6), 2-Level (C5-C6, C6-C7) and 3-Level (C5-C6, C6-C7, C4-C5) conditions. 3D motions sensors were mounted at C4, C5, and C6. Motion data for translations and rotations at each level for each surgical condition and loading mode were compared to intact conditions. Results 1-Level: The index surgery resulted in statistically increased translations in extension and lateral bending at all levels with statistically increased translation observed in flexion in the superior and inferior levels. In rotation, the index surgeries decreased rotation under flexion, with remaining levels not statistically different to intact conditions. 2-Level A device placed inferiorly resulted in statistically increased translations at all levels in extension with statistically increased translations superior and inferior to the index level in flexion. Lateral bending resulted in increased nonsignificant translations. Rotations were elevated or comparable to the intact level for all loading. 3-Level Translations were statistically increased for all levels in all loading modes while rotations were elevated or were comparable to the intact level for all loading modes and levels. Conclusions Micromotion sensors permitted monitoring and recording of small magnitude angulations and translations using a loading mechanism that did not over constrain cervical segmental motion. Multilevel cervical disc arthroplasty yielded comparable or increased overall motion at the index and adjacent levels compared to intact conditions.
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Affiliation(s)
- Todd H. Lanman
- Cedars-Sinai Spine Center, 444 S San Vicente Blvd #800 #901, Los Angeles, CA 90048
| | - Jason M. Cuellar
- Cedars-Sinai Spine Center, 444 S San Vicente Blvd #800 #901, Los Angeles, CA 90048
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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: 0] [Impact Index Per Article: 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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Nishida N, Tripathi S, Mumtaz M, Kelkar A, Kumaran Y, Sakai T, Goel VK. The Effect of Anterior-Only, Posterior-Only, and Combined Anterior Posterior Fixation for Cervical Spine Injury with Soft Tissue Injury: A Finite Element Analysis. World Neurosurg 2023; 171:e777-e786. [PMID: 36584897 DOI: 10.1016/j.wneu.2022.12.105] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 12/24/2022] [Accepted: 12/25/2022] [Indexed: 12/28/2022]
Abstract
OBJECTIVE This finite element analysis aimed to investigate the effects of surgical procedures for cervical spine injury. METHODS A three-dimensional finite element model of the cervical spine (C2-C7) was created from computed tomography. This model contained vertebrae, intervertebral discs, anterior longitudinal ligament, and posterior ligament complex. To create the cervical spine injury model, posterior ligament complex and anterior longitudinal ligament at C3-C4 were resected and the center of the intervertebral disc was resected. We created posterior-only fixation (PF), anterior-only fixation (AF), and combined anterior-posterior fixation (APF) models. A pure moment with a compressive follower load was applied, and range of motion, annular/nucleus stress, instrument stress, and facet forces were analyzed. RESULTS In all motion except for flexion, range of motion of PF, AF, and APF models decreased by 80%-95%, 85%-93%, and 97%-99% compared with the intact model. C3-C4 annulus stress of PF, AF, and APF models decreased by 28%-72%, 96%-100%, and 99%-100% compared with the intact model. Facet contact forces of PF, AF, and APF models decreased by 77%-79%, 97%-99%, and 77%-86% at C3-C4 compared with the intact model. Screw stress in the PF model was higher than in the APF model, and plate stress in the AF model was lower than in the APF model, but bone graft stress in the AF model was higher than in the APF model. CONCLUSIONS Cervical stabilization was preserved by the APF model. Regarding range of motion, the PF model had an advantage compared with the AF model except for flexion. An understanding of biomechanics provides useful information for the clinician.
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Affiliation(s)
- Norihiro Nishida
- Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan.
| | - Sudharshan Tripathi
- Engineering Center for Orthopaedic Research Excellence, Departments of Bioengineering and Orthopaedics, University of Toledo, Toledo, Ohio, USA
| | - Muzammil Mumtaz
- Engineering Center for Orthopaedic Research Excellence, Departments of Bioengineering and Orthopaedics, University of Toledo, Toledo, Ohio, USA
| | - Amey Kelkar
- Engineering Center for Orthopaedic Research Excellence, Departments of Bioengineering and Orthopaedics, University of Toledo, Toledo, Ohio, USA
| | - Yogesh Kumaran
- Engineering Center for Orthopaedic Research Excellence, Departments of Bioengineering and Orthopaedics, University of Toledo, Toledo, Ohio, USA
| | - Takashi Sakai
- Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, Yamaguchi, Japan
| | - Vijay K Goel
- Engineering Center for Orthopaedic Research Excellence, Departments of Bioengineering and Orthopaedics, University of Toledo, Toledo, Ohio, USA
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Li Y, Chen Q, Shu X, Liao Y, Zeng Q, Pou KC, Cai L, Huang Z, Tang S. Biomechanical Effect of Osteoporosis on Adjacent Segments After Anterior Cervical Corpectomy and Fusion. World Neurosurg 2023; 171:e432-e439. [PMID: 36521758 DOI: 10.1016/j.wneu.2022.12.035] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 12/06/2022] [Accepted: 12/07/2022] [Indexed: 12/14/2022]
Abstract
BACKGROUND Adjacent segmental degeneration (ASD) is one common long-term complication of anterior cervical corpectomy and fusion (ACCF), and osteoporosis is one basic disease in the elderly. After ACCF, patients may experience osteoporosis with age. However, the influence of osteoporosis on ASD remains unclear. The purpose of this study was to determine whether osteoporosis could affect the development of ASD following ACCF. METHODS Three finite element models of the cervical spine, including 1 normal model, 1 ACCF model, and 1 ACCF with osteoporosis model, were constructed. ACCF was simulated at the C4-C6 level. A 73.6 N follower load and a 1 Nm moment were imposed on the normal model, and the same follower load together with an adjusted moment was applied to the ACCF model and the ACCF with osteoporosis model, to simulate movement in each direction. The range of motion, intradiscal pressure, shear stress on anulus fibrosus, and facet joint stress at C3-C4 and C6-C7 levels of the models were calculated. RESULTS In this study, the normal model was well validated. In flexion, extension, right lateral bending, and right axial rotation, the overall range of motion was 8.92°, 19.7°, 15.37°, and 45.27° in the normal model, and the adjusted moment was 1.4 Nm, 2.7 Nm, 1.1 Nm, and 2.6 Nm in the ACCF model, and 1.3 Nm, 2.5 Nm, 1.1 Nm, and 2.4 Nm in the ACCF with osteoporosis model. Despite of a few exceptions, the maximum values of the outcome measurements were mostly found in the ACCF model, and the minimum values in the normal model. Compared with the ACCF model, most of the outcome measurements were decreased in the ACCF with osteoporosis model. CONCLUSIONS Osteoporosis can retard the adverse influence of ACCF on adjacent segments.
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Affiliation(s)
- Yixuan Li
- School of Chinese Medicine, Jinan University, Guangzhou, China
| | - Qian Chen
- School of Chinese Medicine, Jinan University, Guangzhou, China
| | - Xinnong Shu
- General Hospital of Southern Theater Command, People's Liberation Army, Guangzhou, China
| | - Yi Liao
- School of Chinese Medicine, Jinan University, Guangzhou, China
| | - Qiuhong Zeng
- School of Chinese Medicine, Jinan University, Guangzhou, China
| | - Kuok Chou Pou
- School of Chinese Medicine, Jinan University, Guangzhou, China
| | - Lulu Cai
- School of Chinese Medicine, Jinan University, Guangzhou, China
| | - Zhen Huang
- School of Chinese Medicine, Jinan University, Guangzhou, China
| | - Shujie Tang
- School of Chinese Medicine, Jinan University, Guangzhou, China.
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Ceramics in total disc replacements: A scoping review. Clin Biomech (Bristol, Avon) 2022; 100:105796. [PMID: 36435073 DOI: 10.1016/j.clinbiomech.2022.105796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 10/04/2022] [Accepted: 10/07/2022] [Indexed: 02/07/2023]
Abstract
BACKGROUND Ceramics are used in Total Disc Replacements (1) in articulating surfaces for their wear resistance and biocompatibility and (2) on endplates to promote osseointegration. They furthermore exhibit MRI and CT compatibility. These properties address main challenges associated with non-ceramic Total Disc Replacements i.e. wear, migration and postoperative imaging. While brittleness of ceramics caused fear of fracture in the past, improvements of ceramic materials were made and considerable clinical experience with ceramic Total Disc Replacements was gained. This review aims to assess the evidence on the use of ceramics in Total Disc Replacements and compare safety and effectiveness of ceramic Total Disc Replacements to spinal fusion and Total Disc Replacements in general. METHODS We conducted a scoping review on the use of ceramics in Total Disc Replacements using Scopus, Web of Science and PubMed. The review includes 36 clinical, ex vivo and nonhuman in vivo, tribological and mechanical studies and case reports. FINDINGS Ceramics are used in cervical Total Disc Replacements, with safety and efficacy confirmed in clinical studies, with up to 10 and 3.3 years follow-up, for articulation and osseointegration applications, respectively. Clinical evidence shows that ceramic Total Disc Replacements (alike non-ceramic ones) restore segmental motion and result in non-inferior and possibly superior outcomes to spinal fusion. In vivo studies show osseointegration comparable to non-ceramic devices. Tribological studies suggest appropriate wear properties. INTERPRETATION We found no indications of systematic problems with the use of ceramics in Total Disc Replacements. Ceramics are suitable materials for Total Disc Replacements.
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Tang B, Yang J, Zhang Y, Ren X, Jiang T, Mo Z, Fan Y. Incorporating strategy in hybrid surgery for continuous two-level cervical spondylosis from a biomechanical perspective. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2022; 226:107193. [PMID: 36288687 DOI: 10.1016/j.cmpb.2022.107193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 10/14/2022] [Accepted: 10/18/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND AND OBJECTIVE Hybrid surgery, incorporating cervical disc replacement and anterior cervical discectomy and fusion, has shown good clinical results in the treatment of multilevel cervical spondylosis according to early follow-ups. This study investigated the surgical strategy of hybrid surgery for two-level cervical spondylosis by distinguishing the biomechanical characteristics with different incorporating modes. METHOD A finite element model of a healthy cervical spine including C2-T1 was developed, and hybrid surgery was simulated by replacing at one level with Prestige-LP and fusion at another level with the anterior plate in C3-C5 (Hybrid-S1: replaced at C3-C4, Hybrid-S2: replaced at C4-C5), and in C4-C6 (Hybrid-M1: replaced at C4-C5, Hybrid-M2: replaced at C5-C6) and in C5-C7 (Hybrid-U1: replaced at C5-C6, Hybrid-U2: replaced at C6-C7). The motion of C2 vertebrae in flexion, extension, axial rotation, and lateral bending was imposed on all hybrid models following the displacement control testing protocol. RESULTS The largest range of motion (ROM) in a healthy spine was observed at C5-C6, followed by C3-C4, C4-C5 and C6-C7. On average, the ROM at the replaced segment increased by 175.7%, 202.7%, 176.3%, 117.1%, 139.4%, and 236.0% in Hybrid-S1, Hybrid-S2, Hybrid-M1, Hybrid-M2, Hybrid-U1, and Hybrid-U2, respectively. The facet joint stress at the replaced segment increased by 186.9%, 124.4%, 111.1%, 60.3%, 62.7%, and 144.7%, and the adjacent intradiscal pressure (IDP) increased by 45.2%, 38.7%, 2.7%, 2.1%, 13.9%, and 20.1%. CONCLUSIONS Incorporating mode in hybrid surgery affects cervical biomechanics. Hybrid surgery with replacement at a segment with a greater ROM and fusion at a segment with a lower ROM can results in fewer changes in terms of overall cervical stiffness, ROM at the operative level, facet joint stress, and adjacent IDP. In hybrid surgery, it is better to implement disc replacement at a level with a greater ROM and fusion of another segment.
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Affiliation(s)
- Beichuan Tang
- Department of Orthopedics, Xinqiao Hospital, Army Medical University (Third Military Medical University), 400037, Chongqing, PR China
| | - Jiemeng Yang
- Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, Key Laboratory of Human Motion Analysis and Rehabilitation Technology of the Ministry of Civil Affairs, National Research Centre for Rehabilitation Technical Aids, 100176, Beijing, PR China; Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing 100083, PR China
| | - Yingying Zhang
- Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, Key Laboratory of Human Motion Analysis and Rehabilitation Technology of the Ministry of Civil Affairs, National Research Centre for Rehabilitation Technical Aids, 100176, Beijing, PR China; Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing 100083, PR China
| | - Xianjun Ren
- Department of Orthopedics, Xinqiao Hospital, Army Medical University (Third Military Medical University), 400037, Chongqing, PR China
| | - Tao Jiang
- Department of Orthopedics, Xinqiao Hospital, Army Medical University (Third Military Medical University), 400037, Chongqing, PR China.
| | - Zhongjun Mo
- Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, Key Laboratory of Human Motion Analysis and Rehabilitation Technology of the Ministry of Civil Affairs, National Research Centre for Rehabilitation Technical Aids, 100176, Beijing, PR China.
| | - Yubo Fan
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing 100083, PR China.
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Zavras AG, Dandu N, Nolte MT, Butler AJ, Federico VP, Sayari AJ, Sullivan TB, Colman MW. Segmental range of motion after cervical total disc arthroplasty at long-term follow-up: a systematic review and meta-analysis. J Neurosurg Spine 2022; 37:579-587. [PMID: 35453108 DOI: 10.3171/2022.2.spine2281] [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: 01/18/2022] [Accepted: 02/21/2022] [Indexed: 11/06/2022]
Abstract
OBJECTIVE As an alternative procedure to anterior cervical discectomy and fusion, total disc arthroplasty (TDA) facilitates direct neural decompression and disc height restoration while also preserving cervical spine kinematics. To date, few studies have reported long-term functional outcomes after TDA. This paper reports the results of a systematic review and meta-analysis that investigated how segmental range of motion (ROM) at the operative level is maintained with long-term follow-up. METHODS PubMed and MEDLINE were queried for all published studies pertaining to cervical TDA. The methodology for screening adhered strictly to the PRISMA guidelines. All English-language prospective studies that reported ROM preoperatively, 1 year postoperatively, and/or at long-term follow-up of 5 years or more were included. A meta-analysis was performed using Cochran's Q and I2 to test data for statistical heterogeneity, in which case a random-effects model was used. The mean differences (MDs) and associated 95% confidence intervals (CIs) were reported. RESULTS Of the 12 studies that met the inclusion criteria, 8 reported the long-term outcomes of 944 patients with an average (range) follow-up of 99.86 (60-142) months and were included in the meta-analysis. There was no difference between preoperative segmental ROM and segmental ROM at 1-year follow-up (MD 0.91°, 95% CI -1.25° to 3.07°, p = 0.410). After the exclusion of 1 study from the comparison between preoperative and 1-year ROM owing to significant statistical heterogeneity according to the sensitivity analysis, ROM significantly improved at 1 year postoperatively (MD 1.92°, 95% CI 1.04°-2.79°, p < 0.001). However, at longer-term follow-up, the authors again found no difference with preoperative segmental ROM, and no study was excluded on the basis of the results of further sensitivity analysis (MD -0.22°, 95% CI -1.69° to -1.23°, p = 0.760). In contrast, there was a significant decrease in ROM from 1 year postoperatively to final long-term follow-up (MD -0.77°, 95% CI -1.29° to -0.24°, p = 0.004). CONCLUSIONS Segmental ROM was found to initially improve beyond preoperative values for as long as 1 year postoperatively, but then ROM deteriorated back to values consistent with preoperative motion at long-term follow-up. Although additional studies with further longitudinal follow-up are needed, these findings further support the notion that cervical TDA may successfully maintain physiological spinal kinematics over the long term.
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Zeng HZ, Zheng LD, Xu ML, Zhu SJ, Zhou L, Candito A, Wu T, Zhu R, Chen Y. Biomechanical effect of age-related structural changes on cervical intervertebral disc: A finite element study. Proc Inst Mech Eng H 2022; 236:1541-1551. [DOI: 10.1177/09544119221122007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Previous literature has investigated the biomechanical response of healthy and degenerative discs, but the biomechanical response of suboptimal healthy intervertebral discs received less attention. The purpose was to compare the biomechanical responses and risk of herniation of young healthy, suboptimal healthy, and degenerative intervertebral discs. A cervical spine model was established and validated using the finite element method. Suboptimal healthy, mildly, moderately, and severely degenerative disc models were developed. Disc height deformation, range of motion, intradiscal pressure, and von Mises stress in annulus fibrosus were analyzed by applying a moment of 4 Nm in flexion, extension, lateral bending, and axial rotation with 100 N compressive loads. Disc height deformation in young healthy, suboptimal healthy, mildly, moderately, and severely degenerative discs was 40%, 37%, 21%, 12%, and 8%, respectively. The decreasing order of the range of motion was young healthy spine > suboptimal healthy spine > mildly degenerative spine > moderately degenerative spine > severely degenerative spine. The mean stress of annulus ground substance in the suboptimal healthy disc was higher than in the young healthy disc. The mean stress of inter-lamellar matrix and annulus ground substance in moderately and severely degenerative discs was higher than in other discs. Age-related structural changes and degenerative changes increased the stiffness and reduced the elastic deformation of intervertebral discs. Decreased range of motion due to the effects of aging or degeneration on the intervertebral disc, may cause compensation of adjacent segments and lead to progressive degeneration of multiple segments. The effect of aging on the intervertebral disc increased the risk of annulus fibrosus damage from the biomechanical point of view. Moderately and severely degenerative discs may have a higher risk of herniation due to the higher risk of damage and layers separation of annulus fibrosus caused by increased stress in the annulus ground substance and inter-lamellar matrix.
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Affiliation(s)
- Hui-zi Zeng
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of the Ministry of Education, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Liang-dong Zheng
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of the 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 the 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 the Ministry of Education, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
| | - Liang Zhou
- Shanghai University of Medicine & Health Sciences, Shanghai, China
| | - Antonio Candito
- Institute of Mechanical, Process and Energy Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, UK
| | - Tao Wu
- Shanghai University of Medicine & Health Sciences, Shanghai, China
| | - Rui Zhu
- Key Laboratory of Spine and Spinal Cord Injury Repair and Regeneration of the Ministry of Education, Tongji Hospital, School of Medicine, Tongji University, Shanghai, China
- Shanghai Clinical Research Center for Ageing and Medicine, Shanghai, China
| | - Yuhang Chen
- Institute of Mechanical, Process and Energy Engineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh, UK
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11
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Li J, Gan K, Chen B, Chen Y, Hong J, Bei D, Fan T, Zheng M, Zhao L, Zhao F. Anterior cervical transpedicular screw fixation system in subaxial cervical spine: A finite element comparative study. Medicine (Baltimore) 2022; 101:e29316. [PMID: 35866798 PMCID: PMC9302373 DOI: 10.1097/md.0000000000029316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Multilevel cervical corpectomy has raised the concern among surgeons that reconstruction with the anterior cervical screw plate system (ACSPS) alone may fail eventually. As an alternative, the anterior cervical transpedicular screw (ACTPS) has been adopted in clinical practice. We used the finite element analysis to investigate whether ACTPS is a more reasonable choice, in comparison with ACSPS, after a 2-level corpectomy in the subaxial cervical spine. These 2 types of implantation models with the applied 75 N axial pressure and 1 N • m pure moment of the couple were evaluated. Compared with the intact model, the range of motion (ROM) at the operative segments (C4-C7) decreased by 97.5% in flexion-extension, 91.3% in axial rotation, and 99.3% in lateral bending in the ACTPS model, whereas it decreased by 95.1%, 73.4%, 96.9% in the ACSPS model respectively. The ROM at the adjacent segment (C3/4) in the ACTPS model decreased in all motions, while that of the ACSPS model increased in axial rotation and flexion-extension compared with the intact model. Compared to the ACSPS model, whose stress concentrated on the interface between the screws and the titanium plate, the stress of the ACTPS model was well-distributed. There was also a significant difference between the maximum stress value of the 2 models. ACTPS and ACSPS are biomechanically favorable. The stability in reducing ROM of ACTPS may be better and the risk of failure for internal fixator is relatively low compared with ACSPS fixation except for under lateral bending in reconstruction the stability of the subaxial cervical spine after 2-level corpectomy.
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Affiliation(s)
- Jie Li
- Department of Orthopedics surgery, Ningbo Medical Center Li Huili Hospital, Affiliated to Ningbo University, Ningbo 315040, Zhejiang, China
| | - Kaifeng Gan
- Department of Orthopedics surgery, Ningbo Medical Center Li Huili Hospital, Affiliated to Ningbo University, Ningbo 315040, Zhejiang, China
| | - Binhui Chen
- Department of Orthopedics surgery, Ningbo Medical Center Li Huili Hospital, Affiliated to Ningbo University, Ningbo 315040, Zhejiang, China
| | - Yilei Chen
- Department of Orthopedics, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, Zhejiang, China
| | - Jinjiong Hong
- Department of spinal surgery, Ningbo 6th hospital, Ningbo 315040, zhejiang, China
| | - Dikai Bei
- Department of Orthopedics surgery, Ningbo Medical Center Li Huili Hospital, Affiliated to Ningbo University, Ningbo 315040, Zhejiang, China
| | - Tengdi Fan
- Department of Orthopedics surgery, Ningbo Medical Center Li Huili Hospital, Affiliated to Ningbo University, Ningbo 315040, Zhejiang, China
| | - Minzhe Zheng
- Department of Orthopedics surgery, Ningbo Medical Center Li Huili Hospital, Affiliated to Ningbo University, Ningbo 315040, Zhejiang, China
| | - Liujun Zhao
- Department of spinal surgery, Ningbo 6th hospital, Ningbo 315040, zhejiang, China
- *Correspondence: Fengdong Zhao, Department of Orthopedics, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, No. 3, Qingchun Road East, Hangzhou 310016, People’s Republic of China (e-mail: )
| | - Fengdong Zhao
- Department of Orthopedics, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, Hangzhou 310016, Zhejiang, China
- *Correspondence: Fengdong Zhao, Department of Orthopedics, Sir Run Run Shaw Hospital, School of Medicine, Zhejiang University, No. 3, Qingchun Road East, Hangzhou 310016, People’s Republic of China (e-mail: )
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12
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Jin K, Zhu Y, Li N, Li Y, Yao Y, Mo Z, Fan Y. Biomechanical effect of posterior ligament repair in lamina repair surgery. Comput Methods Biomech Biomed Engin 2022; 26:799-806. [PMID: 35762201 DOI: 10.1080/10255842.2022.2089024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Cervical laminectomy has usually been applied in treating cervical spinal cord tumour. However, spinal instability after laminectomy was observed with high occurrence rate, due to excising of posterior structures. This study was to investigate the biomechanical performances of ligament repair on the cervical stability in lamina repair surgery. A finite element of cervical spine model (C2-C7) was developed, and lamina repair surgery with and without ligament repair was simulated at C3-C6 segments. All models were loaded with pure moment of 1.5 Nm to produce flexion, extension, lateral blending and axial torsion. Compared to intact model, the range of motion (ROM) at C2-C3, C6-C7 increased by 12.8%-113.6% in lamina repair model (LRM), while the change of ROM in other segments was less than 9.2%. The change of ROM in all segments in the lamina and ligament repair model (LLRM) was less than 7.2%. The maximal intradiscal pressure (IDP) in adjacent segment (C2-C3 and C6-C7) increased by 73.7%, and the maximal stresses in capsular ligament increased by 168.6% in LRM model. By the other hand, the change of facet joint contact stress, IDP and stresses in capsular ligament in LLRM model were less than 11.5%. The differences of stresses on bone-screw interface and screw-plate system in C4,C5 between LRM and LLRM were less than 5.9 MPa (2.7%), but this value in C3 and C6 were up to 105.7 MPa (41.8%). Laminectomy without reconstruction of posterior ligament resulted larger mobility in the adjacent segments, which might induce spinal instability as postoperative complications. Repairing or preserving the posterior ligament in the lamina repair is benefit to spinal integrity and stability.
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Affiliation(s)
- Kaixiang Jin
- Key Laboratory of Biomechanics and Mechanobiology, Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, P. R. China.,School of Engineering Medicine, Beihang University, Beijing, P. R. China
| | - Yuanjun Zhu
- Key Laboratory of Biomechanics and Mechanobiology, Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, P. R. China
| | - Nan Li
- Department of Spine Surgery, Beijing Jishuitan Hospital, Beijing, P. R. China
| | - Yinghui Li
- Beijing No.2 Middle School, Beijing, P. R. China
| | - Yan Yao
- Key Laboratory of Biomechanics and Mechanobiology, Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, P. R. China.,School of Engineering Medicine, Beihang University, Beijing, P. R. China
| | - Zhongjun Mo
- Beijing Key Laboratory of Rehabilitation Technical Aids for Old-Age Disability, Key Laboratory of Technical Aids Analysis and Identification Key Laboratory of the Ministry of Civil Affairs, National Research Centre for Rehabilitation Technical Aids, Beijing, P. R. China
| | - Yubo Fan
- Key Laboratory of Biomechanics and Mechanobiology, Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, P. R. China.,School of Engineering Medicine, Beihang University, Beijing, P. R. China
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13
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Nishida N, Mumtaz M, Tripathi S, Kelkar A, Kumaran Y, Sakai T, Goel VK. Biomechanical analysis of laminectomy, laminoplasty, posterior decompression with instrumented fusion, and anterior decompression with fusion for the kyphotic cervical spine. Int J Comput Assist Radiol Surg 2022; 17:1531-1541. [PMID: 35723866 DOI: 10.1007/s11548-022-02692-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 05/27/2022] [Indexed: 11/26/2022]
Abstract
PURPOSE Anterior and posterior decompressions for cervical myelopathy and radiculopathy may lead to clinical improvements. However, patients with kyphotic cervical alignment have sometimes shown poor clinical outcomes with posterior decompression. There is a lack on report of mechanical analysis of the decompression procedures for kyphotic cervical alignment. METHODS This study employed a three-dimensional finite element (FE) model of the cervical spine (C2-C7) with the pre-operative kyphotic alignment (Pre-OK) model and compared the biomechanical parameters (range of motion (ROM), annular stresses, nucleus stresses, and facet contact forces) for four decompression procedures at two levels (C3-C5); laminectomy (LN), laminoplasty (LP), posterior decompression with fusion (PDF), and anterior decompression with fusion (ADF). Pure moment with compressive follower load was applied to these models. RESULTS PDF and ADF models' global ROM were 40% at C2-C7 less than the Pre-OK, LN, and LP models. The annular and nucleus stresses decreased more than 10% at the surgery levels for ADF, and PDF, compared to the Pre-OK, LN, and LP models. However, the annular stresses at the adjacent cranial level (C2-C3) of ADF were 20% higher. The nucleus stresses of the caudal adjacent level (C5-C6) of PDF were 20% higher, compared to other models. The PDF and ADF models showed a less than 70% decrease in the facet forces at the surgery levels, compared to the Pre-OK, LN, and LP models. CONCLUSION The study concluded that posterior decompression, such as LN or LP, increases ROM, disc stress, and facet force and thus can lead to instability. Although there is the risk of adjacent segment disease (ASD), PDF and ADF can stabilize the cervical spine even for kyphotic alignments.
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Affiliation(s)
- Norihiro Nishida
- Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube City, Yamaguchi Prefecture, 755-8505, Japan
| | - Muzammil Mumtaz
- Engineering Center for Orthopaedic Research Excellence (E-CORE), Departments of Bioengineering and Orthopaedics, The University of Toledo, Toledo, OH, USA
| | - Sudharshan Tripathi
- Engineering Center for Orthopaedic Research Excellence (E-CORE), Departments of Bioengineering and Orthopaedics, The University of Toledo, Toledo, OH, USA
| | - Amey Kelkar
- Engineering Center for Orthopaedic Research Excellence (E-CORE), Departments of Bioengineering and Orthopaedics, The University of Toledo, Toledo, OH, USA
| | - Yogesh Kumaran
- Engineering Center for Orthopaedic Research Excellence (E-CORE), Departments of Bioengineering and Orthopaedics, The University of Toledo, Toledo, OH, USA
| | - Takashi Sakai
- Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, 1-1-1 Minami-Kogushi, Ube City, Yamaguchi Prefecture, 755-8505, Japan
| | - Vijay K Goel
- Engineering Center for Orthopaedic Research Excellence (E-CORE), Departments of Bioengineering and Orthopaedics, The University of Toledo, Toledo, OH, USA.
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14
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Li N, Zhang Y, Tang Q, Wang H, He D, Yao Y, Fan Y. Porous interbody fusion cage design via topology optimization and biomechanical performance analysis. Comput Methods Biomech Biomed Engin 2022; 26:650-659. [PMID: 35652627 DOI: 10.1080/10255842.2022.2081505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The porous interbody fusion cage could provide space and stable mechanical conditions for postoperative intervertebral bone ingrowth. It is considered to be an important implant in anterior cervical discectomy and internal fixation. In this study, two types of unit cells were designed using topology optimization method and introduced to the interbody fusion cage to improve the biomechanical performances of the cage. Topology optimization under two typically loading conditions was first conducted to obtain two unit cells (O-unit cell and D-unit cell) with the same volume fraction. Porous structures were developed by stacking the obtained unit cells in space, respectively. Then, porous interbody fusion cages were obtained by the Boolean intersection between the global structural layout and the porous structures. Finite element models of cervical spine were created that C5-C6 segment was fused by the designed porous cages. The range of motion (ROM) of the cervical spine, the maximum stress on the cage and the bone graft, and the stress and displacement distributions of the cage were analyzed. The results showed the ROMs of C5-C6 segment in D-unit cell and O-unit cell models were range from 0.14° to 0.25° under different loading conditions; the cage composed of the D-unit cells had a more uniform stress distribution, smaller displacement on cage, a more reasonable internal stress transfer mode (transmission along struts of the unit cell), and higher stress on the internal bone graft (0.617 MPa). In conclusion, the optimized porous cage is a promising candidate for fusion surgery, which would avoid the cage subsidence, and promote the fusion of adjacent endplates.
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Affiliation(s)
- Nan Li
- Department of Spine Surgery, Beijing Jishuitan Hospital, The Fourth Clinical Medical College of Peking University, Beijing, China
| | - Yang Zhang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Qiaohong Tang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Hongkun Wang
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Da He
- Department of Spine Surgery, Beijing Jishuitan Hospital, The Fourth Clinical Medical College of Peking University, Beijing, China
| | - Yan Yao
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Engineering Medicine, Beihang University, Beijing, China
| | - Yubo Fan
- Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China.,Key Laboratory of Biomechanics and Mechanobiology (Beihang University), Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Engineering Medicine, Beihang University, Beijing, China
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15
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Nishida N, Tripathi S, Mumtaz M, Kelkar A, Kumaran Y, Sakai T, Goel VK. Soft Tissue Injury in Cervical Spine Is a Risk Factor for Intersegmental Instability: A Finite Element Analysis. World Neurosurg 2022; 164:e358-e366. [PMID: 35513283 DOI: 10.1016/j.wneu.2022.04.112] [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: 03/10/2022] [Revised: 04/25/2022] [Accepted: 04/26/2022] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Soft tissue cervical spine injury (CSI) has the possibility of causing cervical segmental instability, which can lead to spinal cord injury. There is a lack of certainty in assessing whether soft tissue CSI is unstable or not. This biomechanical study aimed to investigate the risk factors of soft tissue CSI. METHODS A 3-dimensional finite element model of the ligamentous cervical spine (C2-C7) was created from medical images. Three soft tissue injury models were simulated at C4-C5: 1) posterior ligament complex (PLC) injury, 2) intervertebral disk (ID) with anterior longitudinal ligament injury (IDI), and 3) anterior longitudinal ligament, PLC, and ID injury (API) model. Pure moment with compressive follower load was applied, and the range of motion, annular stress, nucleus stress, and facet forces were analyzed. RESULTS For the IDI and API models, the range of motion increased at the injury level in extension (by 101%) and left/right axial rotations (>30%) compared with the intact model. The IDI and API models showed an increase of >50% in annular and nucleus stresses at the injury level in extension and left/right rotations compared with the intact model. The PLC injury showed similar stresses as the intact model except for flexion. The facet contact forces of IDI and API models increased more than 100% compared with other models in all motions. CONCLUSIONS In CSI, all soft tissues have a key role in stabilizing cervical spine, but ID is the most important component of all.
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Affiliation(s)
- Norihiro Nishida
- Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, Ube City, Yamaguchi Prefecture, Japan.
| | - Sudharshan Tripathi
- Engineering Center for Orthopaedic Research Excellence (E-CORE), Departments of Bioengineering and Orthopaedics, The University of Toledo, Toledo, Ohio, USA
| | - Muzammil Mumtaz
- Engineering Center for Orthopaedic Research Excellence (E-CORE), Departments of Bioengineering and Orthopaedics, The University of Toledo, Toledo, Ohio, USA
| | - Amey Kelkar
- Engineering Center for Orthopaedic Research Excellence (E-CORE), Departments of Bioengineering and Orthopaedics, The University of Toledo, Toledo, Ohio, USA
| | - Yogesh Kumaran
- Engineering Center for Orthopaedic Research Excellence (E-CORE), Departments of Bioengineering and Orthopaedics, The University of Toledo, Toledo, Ohio, USA
| | - Takashi Sakai
- Department of Orthopedic Surgery, Yamaguchi University Graduate School of Medicine, Ube City, Yamaguchi Prefecture, Japan
| | - Vijay K Goel
- Engineering Center for Orthopaedic Research Excellence (E-CORE), Departments of Bioengineering and Orthopaedics, The University of Toledo, Toledo, Ohio, USA
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16
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Zavras AG, Sullivan TB, Singh K, Phillips FM, Colman MW. Failure in cervical total disc arthroplasty: single institution experience, systematic review of the literature, and proposal of the RUSH TDA failure classification system. Spine J 2022; 22:353-369. [PMID: 34419625 DOI: 10.1016/j.spinee.2021.08.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 08/10/2021] [Accepted: 08/13/2021] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Cervical total disc arthroplasty (TDA) is an alternative procedure to anterior cervical discectomy and fusion that facilitates neural decompression while both preserving motion of the spinal unit and decreasing the risk for degenerative changes at adjacent segments. However, due to its more recent introduction in clinical practice and low complication rates, the modes by which TDA may fail remain to be described. PURPOSE This study sought to identify the modes and frequencies of cervical TDA failure in order to propose a novel classification system. STUDY DESIGN Retrospective cohort and systematic review. PATIENT SAMPLE Patients who underwent single or two-level TDA for cervical radiculopathy or myelopathy at a single institution and in the literature of medium and large prospective studies. OUTCOME MEASURES Cervical TDA failure, defined as subsequent surgical intervention at the index segment. METHODS This study retrospectively reviewed patients who underwent single or two-level TDA for cervical radiculopathy or myelopathy at a single institution to identify the potential implant failure modes. A systematic review and meta-analysis of prospective data in the literature was then performed to further supplement failure mode identification and to describe the rates at which the various failure types occurred. Statistical analysis included between-group comparisons of Non-Failed and Failed patients and frequencies of each failure type among Failed patients. RESULTS A retrospective review at our institution of 169 patients (201 levels) identified eight failures, for a failure rate of 4.7%. Additionally, seven patients were revised who had the primary surgery at an outside institution. The systematic review of 3976 patients (4525 levels) identified 165 (4.1%) additional failures. Using this data, six primary failure types were classified, with several subtypes. These include recurrent or persistent index-level stenosis (Type I); migration (Type II) presenting as gross extrusion (A) or endplate failure with subsidence/acute fracture (B); instability (Type III) due to mechanical loosening (A), septic loosening (B), or device fracture (C); device motion loss (Type IV) such as "locking" of the device in kyphosis; implantation error (Type V) due to malposition (A) or improper sizing (B); and wear (Type VI) either without osteolysis (A) or with wear-particle-induced osteolysis (B). Stenosis (Type I) was the most common mode of failure found both through retrospective review and in the literature. CONCLUSIONS Cervical TDA fails through six primary mechanisms. While rates of certain failures requiring subsequent surgical intervention are low, it is possible that these complications may become more prevalent upon further longitudinal observation. Thus, future application and validation of this classification system is warranted to evaluate how failure frequencies change over time and with larger patient samples.
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Affiliation(s)
- Athan G Zavras
- Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St., Chicago, IL 60612, USA
| | - Thomas Barrett Sullivan
- Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St., Chicago, IL 60612, USA
| | - Kern Singh
- Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St., Chicago, IL 60612, USA
| | - Frank M Phillips
- Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St., Chicago, IL 60612, USA
| | - Matthew W Colman
- Department of Orthopaedic Surgery, Rush University Medical Center, 1611 W. Harrison St., Chicago, IL 60612, USA.
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17
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Zhou E, Huang H, Zhao Y, Wang L, Fan Y. The effects of titanium mesh cage size on the biomechanical responses of cervical spine after anterior cervical corpectomy and fusion: A finite element study. Clin Biomech (Bristol, Avon) 2022; 91:105547. [PMID: 34923190 DOI: 10.1016/j.clinbiomech.2021.105547] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2021] [Revised: 12/03/2021] [Accepted: 12/07/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND Due to the lack of sufficient studies focusing on titanium mesh cage size, there exists a puzzle among surgeons about how to determine the optimal size of cage to provide surgical segments an adequate distraction. METHODS The biomechanical responses of cervical spine after the implantation of cages with different heights and trimmed angles were analyzed using the finite element method. Twenty Anterior Cervical Corpectomy and Fusion models, of which the surgical segment was C5, were developed corresponding to the combinations of 4-different-heights and 5-different-trimmed angle cages. Biomechanical parameters were calculated under simulated physiological load of cervical spine. A rating scale was designed to assess the biomechanical performances of titanium mesh cages with different heights and trimmed angles comprehensively, assisting to select the most appropriate combination of cage height and trimmed angle. FINDINGS It was indicated that in the single-level Anterior Cervical Corpectomy and Fusion at C5 segment, a cage with a height fitting with the space between C4 and C6 as well as a trimmed angle 2° lower than the sagittal angle of C4 inferior endplate would provide adequate biomechanical environment for cervical spine to resist cage subsidence and reduce the impact to adjacent segments. INTERPRETATION The biomechanical responses of cervical spine are affected significantly by the height and trimmed angles of titanium mesh cage. The results of this study would provide quantitative guidance for surgeons to determine the optimal height and trimmed angle of titanium mesh cage for a specific patient in order to achieve favorable clinical outcomes.
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Affiliation(s)
- Enze Zhou
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
| | - Huiwen Huang
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
| | - Yanbin Zhao
- Department of Orthopedic Surgery, Peking University Third Hospital, Beijing 100191, China.
| | - Lizhen Wang
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China.
| | - Yubo Fan
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing 100083, China
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18
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Goel V, Mumtaz M, Mendoza J, Tripathi S, Kelkar A, Nishida N, Sahai A. Total disc replacement alters the biomechanics of cervical spine based on sagittal cervical alignment: A finite element study. JOURNAL OF CRANIOVERTEBRAL JUNCTION AND SPINE 2022; 13:278-287. [PMID: 36263350 PMCID: PMC9574107 DOI: 10.4103/jcvjs.jcvjs_21_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 05/08/2022] [Indexed: 11/04/2022] Open
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19
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Patwardhan AG, Havey RM. Biomechanics of Cervical Disc Arthroplasty Devices. Neurosurg Clin N Am 2021; 32:493-504. [PMID: 34538475 DOI: 10.1016/j.nec.2021.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Prosthesis design has an influence on the quantity and quality of postoperative motion after cervical disc arthroplasty. Prostheses with built-in resistance to angular and translational motion may have an advantage in restoring physiologic motion. The ability of a prosthesis to work with remaining bony and soft tissues to restore motion and load-sharing is a function of the kinematic degrees of freedom DOF, axis of rotation for a given motion, and device stiffness. How these characteristics allow the prosthesis to work with the patient's anatomy will determine whether the prosthesis is successful at restoring motion and mitigating adjacent-level stresses.
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Affiliation(s)
- Avinash G Patwardhan
- Musculoskeletal Biomechanics Laboratory, Edward Hines, Jr. VA Hospital, PO Box 5000, Hines, IL, 60141 USA; Department of Orthopedic Surgery and Rehabilitation, Loyola University Medical Center, 2160 South First Avenue, Maywood, IL 60153, USA.
| | - Robert M Havey
- Musculoskeletal Biomechanics Laboratory, Edward Hines, Jr. VA Hospital, PO Box 5000, Hines, IL, 60141 USA
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Guyer RD, Albano JL, Ohnmeiss DD. Cervical Total Disc Replacement: Novel Devices. Neurosurg Clin N Am 2021; 32:449-460. [PMID: 34538471 DOI: 10.1016/j.nec.2021.05.004] [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] [Indexed: 11/18/2022]
Abstract
This article reviews the available literature for novel cervical total disc replacement devices, including ones which are available inside and outside of the United States. It includes biomechanical consideration as well as design characteristics and clinical data when available.
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Affiliation(s)
- Richard D Guyer
- Center for Disc Replacement at Texas Back Institute, 6020 W. Parker Rd. #200, Plano, TX 75093, USA.
| | - Joseph L Albano
- Texas Back Institute, 6020 W. Parker Rd. #200, Plano, TX 75093, USA
| | - Donna D Ohnmeiss
- Texas Back Institute Research Foundation, 6020 W. Parker Rd. #200, Plano, TX 75093, USA
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A critical review on the biomechanical study of cervical interbody fusion cage. MEDICINE IN NOVEL TECHNOLOGY AND DEVICES 2021. [DOI: 10.1016/j.medntd.2021.100070] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
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22
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Biomechanical Analysis of Posterior Ligaments of Cervical Spine and Laminoplasty. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11167645] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Cervical laminoplasty is a valuable procedure for myelopathy but it is associated with complications such as increased kyphosis. The effect of ligament damage during cervical laminoplasty on biomechanics is not well understood. We developed the C2–C7 cervical spine finite element model and simulated C3–C6 double-door laminoplasty. Three models were created (a) intact, (b) laminoplasty-pre (model assuming that the ligamentum flavum (LF) between C3–C6 was preserved during surgery), and (c) laminoplasty-res (model assuming that the LF between C3–C6 was resected during surgery). The models were subjected to physiological loading, and the range of motion (ROM), intervertebral nucleus stress, and facet contact forces were analyzed under flexion/extension, lateral bending, and axial rotation. The maximum change in ROM was observed under flexion motion. Under flexion, ROM in the laminoplasty-pre model increased by 100.2%, 111.8%, and 98.6% compared to the intact model at C3–C4, C4–C5, and C5–C6, respectively. The ROM in laminoplasty-res further increased by 105.2%, 116.8%, and 101.8% compared to the intact model at C3–C4, C4–C5, and C5–C6, respectively. The maximum stress in the annulus/nucleus was observed under left bending at the C4–C5 segment where an increase of 139.5% and 229.6% compared to the intact model was observed for laminoplasty-pre and laminoplasty-res model, respectively. The highest facet contact forces were observed at C4–C5 under axial rotation, where an increase of 500.7% and 500.7% was observed compared to the intact model for laminoplasty-pre and laminoplasty-res, respectively. The posterior ligaments of the cervical spine play a vital role in restoring/stabilizing the cervical spine. When laminoplasty is performed, the surgeon needs to be careful not to injure the posterior soft tissue, including ligaments such as LF.
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Wawrose RA, Howington FE, LeVasseur CM, Smith CN, Couch BK, Shaw JD, Donaldson WF, Lee JY, Patterson CG, Anderst WJ, Bell KM. Assessing the biofidelity of in vitro biomechanical testing of the human cervical spine. J Orthop Res 2021; 39:1217-1226. [PMID: 32333606 PMCID: PMC7606317 DOI: 10.1002/jor.24702] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 12/10/2019] [Accepted: 01/06/2020] [Indexed: 02/06/2023]
Abstract
In vitro biomechanical studies of the osteoligamentous spine are widely used to characterize normal biomechanics, identify injury mechanisms, and assess the effects of degeneration and surgical instrumentation on spine mechanics. The objective of this study was to determine how well four standards in vitro loading paradigms replicate in vivo kinematics with regards to the instantaneous center of rotation and arthrokinematics in relation to disc deformation. In vivo data were previously collected from 20 asymptomatic participants (45.5 ± 5.8 years) who performed full range of motion neck flexion-extension (FE) within a biplane x-ray system. Intervertebral kinematics were determined with sub-millimeter precision using a validated model-based tracking process. Ten cadaveric spines (51.8 ± 7.3 years) were tested in FE within a robotic testing system. Each specimen was tested under four loading conditions: pure moment, axial loading, follower loading, and combined loading. The in vivo and in vitro bone motion data were directly compared. The average in vitro instant center of rotation was significantly more anterior in all four loading paradigms for all levels. In general, the anterior and posterior disc heights were larger in the in vitro models than in vivo. However, after adjusting for gender, the observed differences in disc height were not statistically significant. This data suggests that in vitro biomechanical testing alone may fail to replicate in vivo conditions, with significant implications for novel motion preservation devices such as cervical disc arthroplasty implants.
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Affiliation(s)
- Richard A. Wawrose
- School of Medicine, Department of Orthopaedic Surgery, Ferguson Lab for Orthopaedic Research, University of Pittsburgh, Pittsburgh, PA 15213
| | - Forbes E. Howington
- School of Medicine, Department of Orthopaedic Surgery, Ferguson Lab for Orthopaedic Research, University of Pittsburgh, Pittsburgh, PA 15213
| | - Clarissa M. LeVasseur
- Department of Orthopaedic Surgery, Biodynamics Laboratory, University of Pittsburgh, Pittsburgh, PA 15203
| | - Clair N. Smith
- School of Medicine, Department of Orthopaedic Surgery, Ferguson Lab for Orthopaedic Research, University of Pittsburgh, Pittsburgh, PA 15213
| | - Brandon K. Couch
- School of Medicine, Department of Orthopaedic Surgery, Ferguson Lab for Orthopaedic Research, University of Pittsburgh, Pittsburgh, PA 15213
| | - Jeremy D. Shaw
- School of Medicine, Department of Orthopaedic Surgery, Ferguson Lab for Orthopaedic Research, University of Pittsburgh, Pittsburgh, PA 15213
| | - William F. Donaldson
- School of Medicine, Department of Orthopaedic Surgery, Ferguson Lab for Orthopaedic Research, University of Pittsburgh, Pittsburgh, PA 15213
| | - Joon Y. Lee
- School of Medicine, Department of Orthopaedic Surgery, Ferguson Lab for Orthopaedic Research, University of Pittsburgh, Pittsburgh, PA 15213
| | - Charity G. Patterson
- School of Medicine, Department of Orthopaedic Surgery, Ferguson Lab for Orthopaedic Research, University of Pittsburgh, Pittsburgh, PA 15213
| | - William J. Anderst
- Department of Orthopaedic Surgery, Biodynamics Laboratory, University of Pittsburgh, Pittsburgh, PA 15203
| | - Kevin M. Bell
- School of Medicine, Department of Orthopaedic Surgery, Ferguson Lab for Orthopaedic Research, University of Pittsburgh, Pittsburgh, PA 15213
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Patwardhan AG, Havey RM. Biomechanics of Cervical Disc Arthroplasty-A Review of Concepts and Current Technology. Int J Spine Surg 2020; 14:S14-S28. [PMID: 32994302 DOI: 10.14444/7087] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Activities of daily living require the subaxial cervical spine (C2-C7) to have substantial mobility. Cervical degenerative changes can cause abnormal motions and altered load distribution, leading to pain and limiting the ability of individuals to perform activities of daily living. Anterior cervical discectomy and fusion (ACDF) has been widely used to treat symptomatic cervical spondylosis. Clinical studies have shown cervical disc arthroplasty (CDA) to be a viable alternative to ACDF for the treatment of radiculopathy and myelopathy. The benefits of CDA are based on the premise that preservation of physiologic motions and load-sharing at the treated level would lead to longevity of the index-level facet joints and mitigate the risk of adjacent segment degeneration.This review article classifies cervical disc prostheses according to their kinematic degrees of freedom and device constraints. Discussion on how these design features may affect cervical motion after implantation will provide the reader with valuable information on how disc prostheses may function clinically.The ability of a disc prosthesis to work in concert with remaining bony and soft tissue structures to restore physiologic motion and load-sharing is a function of the following design features and surgical factors: Kinematic degrees of freedom-Prostheses that allow translation independent of rotation allow, in theory, the spinal anatomy to dictate segmental motion after CDA potentially restoring physiologic motion and load-sharing. A 6-degrees-of-freedom disc prosthesis may be best equipped to achieve the intended function of CDA.Built-in stiffness-A disc prosthesis with built-in resistance to angular and translational motion may have an advantage in restoring stability to a hypermobile segment without eliminating motion.Surgical factors related to prosthesis implantation may influence cervical segments after CDA. These factors include the amount of disc space distraction caused by the prosthesis, prosthesis placement in the sagittal and coronal planes, and integrity of the soft tissue envelope.
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Affiliation(s)
- Avinash G Patwardhan
- Musculoskeletal Biomechanics Laboratory, Edward Hines, Jr. VA Hospital, Hines, Illinois.,Department of Orthopaedic Surgery and Rehabilitation, Loyola University Medical Center, Maywood, Illinois
| | - Robert M Havey
- Musculoskeletal Biomechanics Laboratory, Edward Hines, Jr. VA Hospital, Hines, Illinois
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Wu TK, Liu H, Wang BY, He JB, Ding C, Rong X, Yang Y, Huang KK, Hong Y. Incidence of bone loss after Prestige-LP cervical disc arthroplasty: a single-center retrospective study of 396 cases. Spine J 2020; 20:1219-1228. [PMID: 32445801 DOI: 10.1016/j.spinee.2020.05.102] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 05/08/2020] [Accepted: 05/08/2020] [Indexed: 02/08/2023]
Abstract
BACKGROUND CONTEXT The development of bone loss (BL) at the operated level after cervical disc arthroplasty (CDA) has not been well recognized. The incidence of BL may be correlated with the prosthesis type. Currently, no study has reported the incidence of BL after CDA with the Prestige-LP disc, and this remains an active area of research. PURPOSE To determine the incidence of BL after Prestige-LP CDA and evaluate the impact of BL on clinical and radiological outcomes. STUDY DESIGN This is an observational study. PATIENT SAMPLE A total of 396 patients were reviewed. OUTCOME MEASURES The Japanese Orthopedics Association (JOA), Visual Analogue Scale (VAS), and Neck Disability Index (NDI) scores were evaluated. Cervical lordosis, disc angle, global and segmental range of motion (ROM), heterotopic ossification (HO), and BL were measured. METHODS We retrospectively reviewed patients who underwent Prestige-LP disc from January 2008 to October 2018 at our institution. Clinical outcomes were evaluated using JOA, VAS, and NDI scores. Radiological variables, including cervical lordosis, disc angle, global and segmental ROM, HO, and BL, were retrieved. RESULTS A total of 396 patients and 483 CDAs were evaluated. BL occurred in 56.6% of patients and 52.8% of CDA segments. Mild BL occurred in 30.2%, moderate BL in 37.3%, and severe BL in 32.5% of CDA segments. Notably, 88.2% of CDA segments developed BL within the first 3 months, and 19.1% of them progressed at 6 months. However, no progressive BL after 12 months was seen. About 50.2% of CDAs showed superior and inferior endplates involvement. The incidence of BL was associated with age, surgery type, level distribution, and incidence and grade of HO. Patients with BL had a better segmental ROM, but no relationships between patients with or without BL were found in clinical outcomes. CONCLUSIONS BL was a common but self-limited phenomenon after CDA at the early postoperative stage. It occurred more often in relatively young age patients, two-level CDA, and C5/6 segment. However, patients suffering from BL showed no deterioration of the clinical outcomes, more exceptional motion preservation at the arthroplasty level, and lower incidence with a lower grade of HO.
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Affiliation(s)
- Ting-Kui Wu
- Department of Orthopedic Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Rd, Chengdu 610041, China.
| | - Hao Liu
- Department of Orthopedic Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Rd, Chengdu 610041, China.
| | - Bei-Yu Wang
- Department of Orthopedic Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Rd, Chengdu 610041, China.
| | - Jun-Bo He
- Department of Orthopedic Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Rd, Chengdu 610041, China.
| | - Chen Ding
- Department of Orthopedic Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Rd, Chengdu 610041, China.
| | - Xin Rong
- Department of Orthopedic Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Rd, Chengdu 610041, China.
| | - Yi Yang
- Department of Orthopedic Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Rd, Chengdu 610041, China.
| | - Kang-Kang Huang
- Department of Orthopedic Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Rd, Chengdu 610041, China.
| | - Ying Hong
- Department of Operating Room, West China Hospital, Sichuan University, No. 37 Guo Xue Rd, Chengdu 610041, China.
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Nunley PD, Kerr EJ, Cavanaugh DA, Utter PA, Campbell PG, Wadhwa R, Frank KA, Marshall KE, Stone MB. Adjacent Segment Pathology After Treatment With Cervical Disc Arthroplasty or Anterior Cervical Discectomy and Fusion, Part 2: Clinical Results at 7-Year Follow-Up. Int J Spine Surg 2020; 14:278-285. [PMID: 32699748 DOI: 10.14444/7037] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Background Adjacent segment pathology (ASP) following cervical disc arthroplasty (CDA) or anterior cervical discectomy and fusion (ACDF) is identified by imaging (RASP) or clinical symptoms (CASP). Clinical symptoms of CASP have been broadly defined, but subsequent adjacent-level surgeries are clear indicators of CASP. Current literature remains inconsistent in the incidence and potential predictors of CASP. Here, we will evaluate a robust data set for the incidence of CASP resulting in subsequent surgery, attempt to identify factors that might affect CASP, and analyze the association of CASP with patient-reported outcomes (PROS) and RASP. Methods Data were prospectively collected during a US Food and Drug Administration randomized, multicenter, investigational device exemption trial comparing CDA (Mobi-C, Zimmer Biomet, Westminster, CO) with ACDF. CASP was defined as any adjacent-level subsequent surgical intervention. Post hoc analyses were conducted on the incidence, time to CASP diagnosis, and relationship of CASP with patient demographics. Longitudinal retrospective case-control analysis was used to assess the correlation of CASP to PROs and radiographic adjacent segment pathology (RASP). Results Kaplan-Meier estimates indicated significantly lower probability of CASP over time for 1-level (P = .002) and 2-level (P = .008) CDA patients. Treatment with ACDF and younger age were associated with higher CASP risk. CDA was more effective than ACDF (70.5%; 95% CI = 45.1, 84.2; P < .0001) at preventing CASP. Case-control analysis indicated increased probability of CASP for patients with grade 3/4 RASP, but the difference was not statistically significant. When we pooled CASP patients, the median grade of RASP at the visit prior to surgery was 1, with only 6 patients presenting with grade 3/4 RASP. Conclusions Patients treated with CDA have a lower incidence of CASP than do patients treated with ACDF, although the mechanism remains unclear. CASP and RASP remain uncorrelated in this large data set, but other predictive variables such as treatment, age, and number of levels should be further investigated.
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Affiliation(s)
| | | | | | | | | | - Rishi Wadhwa
- Spine Institute of Louisiana, Shreveport, Louisiana
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Cai XY, YuChi CX, Du CF, Mo ZJ. The effect of follower load on the range of motion, facet joint force, and intradiscal pressure of the cervical spine: a finite element study. Med Biol Eng Comput 2020; 58:1695-1705. [DOI: 10.1007/s11517-020-02189-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 05/10/2020] [Indexed: 12/20/2022]
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External and internal responses of cervical disc arthroplasty and anterior cervical discectomy and fusion: A finite element modeling study. J Mech Behav Biomed Mater 2020; 106:103735. [PMID: 32321632 DOI: 10.1016/j.jmbbm.2020.103735] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/27/2019] [Accepted: 03/17/2020] [Indexed: 12/31/2022]
Abstract
Surgical treatment for spinal disorders, such as cervical disc herniation and spondylosis, includes the removal of the intervertebral disc and replacement of biological or artificial materials. In the former case, bone graft is used to fill the space, and this conventional procedure is termed anterior cervical discectomy and fusion (ACDF). The latter surgery is termed as artificial disc replacement ADR) or cervical disc arthroplasty (CDA). Surgeries are most commonly performed at one or two levels. The present study was designed to determine the external (range of motion, ROM) and internal (anterior and posterior load sharing) responses of the spines with one-level and two-level surgeries in both models (ACDF and CDA) using a previously validated finite element model (FEM) of the subaxial cervical spinal column. The FEM simulated the vertebra (cancellous core and cortical shell of the body, posterior elements - laminae, pedicles and spinous processes), discs (anulus fibers, ground substance, and nucleus pulposus), anterior and posterior ligaments of the disc and facet joints, and interspinous and supraspinous ligaments. Appropriate material properties were assigned to the spinal components. The United States Food Drug Administration-approved Mobi-C was used for the CDA option. The FEM was exercised under pure flexion and extension moment loading of 2 Nm in the intact state. The overall ROM of the column was obtained. The hybrid loading protocol applied moments that matched the ROM in the intact spine for both one-level (C5-C6) and two-level (C5-C7) ACDF and CDA surgeries. ROM at the level(s) of surgery, termed the index level was obtained. These data along with anterior column load (ACL) and posterior column load (PCL) sharing were obtained for all surgical options at superior and inferior segments (termed adjacent segment outputs). Results for both one-level and two-level surgeries showed that ACDFs decreases ROM at the index level, while CDAs increase motions compared to the intact normal spine. The ROM, ACL, and PCL increased at both adjacent levels for the ACDF while CDA showed a decrease. Although two-level surgeries resulted in increased these biomechanical variables, greater changes to adjacent segment biomechanics in ACDF may accelerate adjacent segment disease. Decreased ROM and lower load sharing in CDAs may limit adjacent segment effects such as accelerated degeneration. Their increased posterior load sharing, however, may need additional attention for patients with suspected facet joint disease.
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Wong CE, Hu HT, Hsieh MP, Huang KY. Optimization of Three-Level Cervical Hybrid Surgery to Prevent Adjacent Segment Disease: A Finite Element Study. Front Bioeng Biotechnol 2020; 8:154. [PMID: 32195235 PMCID: PMC7064443 DOI: 10.3389/fbioe.2020.00154] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Accepted: 02/14/2020] [Indexed: 12/23/2022] Open
Abstract
Hybrid surgery (HS) allows surgeons to tailor fusion and arthroplasty in the treatment of multiple-level cervical disc degeneration. However, the decision making of selecting either ACDF or ADR for each level in three-level HS remains controversial and has not been fully investigated. This study was aimed to optimize three-level cervical hybrid constructs by systematically investigating their biomechanical properties and their effect on adjacent levels. A finite element model of cervical spine (C2–C7) was developed, and eight C3–C6 surgical models including six HS were constructed. The range of motion (ROM) in flexion, extension, lateral bending, and axial rotation under 2.0 Nm moments with 30 N follower load were simulated. The von Mises stress, strain energy at the adjacent intervertebral disc (IVD) and force at the adjacent facet were calculated. The ROM of the hybrid constructs and adjacent levels was close to that of the intact spine. HS with arthroplasty performed at C5-6 had better performance in terms of ROM reduction at the inferior adjacent level (C6-7). Moreover, C-D-D and 3ADR had best performance in reducing the von Mises stress and strain energy at C6-7. All HS reduced the facet burden at both C2-3 and C6-7 levels. However, the major drawback of HS revealed here is that the effect of C6-7 protection is at the cost of increased C2-3 IVD burden. In conclusion, we recommend C-D-D and 3ADR for patient with C3–C6 disc degeneration without predisposing C2-3 condition. C-C-D could be a good alternative with a lower medical cost. This analysis guides the decision making in three-level cervical HS before future cadaver studies or human clinical trials.
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Affiliation(s)
- Chia-En Wong
- Department of Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Hsuan-Teh Hu
- Department of Civil Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Meng-Pu Hsieh
- Department of Civil Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Kuo-Yuan Huang
- Department of Orthopedics, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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The appropriate hybrid surgical strategy in three-level cervical degenerative disc disease: a finite element analysis. J Orthop Surg Res 2019; 14:444. [PMID: 31842938 PMCID: PMC6915991 DOI: 10.1186/s13018-019-1502-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Accepted: 11/28/2019] [Indexed: 11/10/2022] Open
Abstract
Objective The purpose of this FE study was to analyze the biomechanical characteristics of different HS strategies used in the treatment of three-level CDDD (one-level CDA and two-level ACDF). Methods We validated the FE model of an intact cervical spine established by transferring the data, collected by 3D CT scan, to the FE software ABAQUS and comparing these data with the data from published studies. Then, the FE model of hybrid surgery was reconstructed to analyze the range of motion (ROM), facet joint force, and stress distribution on an ultrahigh molecular weight polyethylene (UHMWPE) core. Results The current cervical FE model was able to measure the biomechanical changes in a follow-up hybrid surgery simulation. The total ROM of the cervical HS models was substantially decreased compared with the total ROM of the intact group, and the M2 (C3/4 ACDF, C4/5 CDA, and C5/6 ACDF) model had the closest total ROM to the intact group, but the facet joint force adjacent to the treatment levels showed very little difference among them. The stress distribution showed noticeable similarity: two flanks were observed in the center core, but the inlay of M2 was more vulnerable. Conclusions Through the comparison of ROM, the facet joint force after CDA, and the stress distribution of the prosthesis, we find that M2 model has a better theoretical outcome, especially in preserving the maximum total ROM.
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Adjacent segment motion following multi-level ACDF: a kinematic and clinical study in patients with zero-profile anchored spacer or plate. 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 2019; 28:2408-2416. [DOI: 10.1007/s00586-019-06109-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 07/14/2019] [Accepted: 08/08/2019] [Indexed: 02/08/2023]
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Prosthesis design influences segmental contribution to total cervical motion after cervical disc arthroplasty. 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 2019; 29:2713-2721. [DOI: 10.1007/s00586-019-06064-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 06/14/2019] [Accepted: 07/04/2019] [Indexed: 10/26/2022]
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Havey RM, Khayatzadeh S, Voronov LI, Blank KR, Carandang G, Harding DP, Patwardhan AG. Motion response of a polycrystalline diamond adaptive axis of rotation cervical total disc arthroplasty. Clin Biomech (Bristol, Avon) 2019; 62:34-41. [PMID: 30665037 DOI: 10.1016/j.clinbiomech.2018.12.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 12/10/2018] [Accepted: 12/20/2018] [Indexed: 02/07/2023]
Abstract
BACKGROUND Cervical fusion is associated with adjacent segment degeneration. Cervical disc arthroplasty is considered an alternative to reduce risk of adjacent segment disease. Kinematics after arthroplasty should closely replicate healthy in vivo kinematics to reduce adjacent segment stresses. The purpose of this study was to assess the kinematics of a polycrystalline diamond cervical disc prosthesis. METHODS Nine cadaveric C3-T1 spines were tested intact and after one (C5-C6) and two level (C5-C7) arthroplasty (Triadyme-C, Dymicron Inc., Orem, UT, USA). Kinematics were evaluated in flexion-extension, lateral bending, and axial rotation. FINDINGS Prosthesis placement at C5-C6 and C6-C7 was 0.5 mm anterior and 0.6 mm posterior to midline respectively. C5-C6 flexion-extension motion was 12.8° intact and 10.5° after arthroplasty. C6-C7 flexion-extension motion was 10.0 and 11.4° after arthroplasty. C5-C6 lateral bending reduced from 8.5 to 3.7° after arthroplasty and at C6-C7 from 7.5 to 5.1°. C5-C6 axial rotation decreased from 10.4 to 6.2° after arthroplasty and at C6-C7 from 7.8 to 5.3°. Segmental lordosis increased by 4.2°, and middle disc height by 1.4 mm after arthroplasty. Change in center of rotation from intact to arthroplasty averaged 0.9 mm posteriorly and 0.1 mm caudally at C5-C6, and 1.4 mm posteriorly and 0.3 mm cranially at C6-C7. INTERPRETATION The cervical disc arthroplasty evaluated restored flexion-extension motion to intact levels and moderately increased segmental stiffness. Disc height increased by up to 1.5 mm and segmental lordosis by 4.2°. The unique prosthesis design allowed the axis of rotation after arthroplasty to closely mimic the native location.
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Affiliation(s)
- Robert M Havey
- Edward Hines Jr. VA Hospital, Hines, IL, USA; Loyola University Medical Center, Maywood, IL, USA.
| | | | - Leonard I Voronov
- Edward Hines Jr. VA Hospital, Hines, IL, USA; Loyola University Medical Center, Maywood, IL, USA
| | | | | | | | - Avinash G Patwardhan
- Edward Hines Jr. VA Hospital, Hines, IL, USA; Loyola University Medical Center, Maywood, IL, USA
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Bell KM, Yan Y, Hartman RA, Lee JY. Influence of follower load application on moment-rotation parameters and intradiscal pressure in the cervical spine. J Biomech 2018; 76:167-172. [PMID: 29929892 DOI: 10.1016/j.jbiomech.2018.05.031] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 05/15/2018] [Accepted: 05/30/2018] [Indexed: 10/28/2022]
Abstract
The objective of this study was to implement a follower load (FL) device within a robotic (universal force-moment sensor) testing system and utilize the system to explore the effect of FL on multi-segment cervical spine moment-rotation parameters and intradiscal pressure (IDP) at C45 and C56. Twelve fresh-frozen human cervical specimens (C3-C7) were biomechanically tested in a robotic testing system to a pure moment target of 2.0 Nm for flexion and extension (FE) with no compression and with 100 N of FL. Application of FL was accomplished by loading the specimens with bilateral cables passing through cable guides inserted into the vertebral bodies and attached to load controlled linear actuators. FL significantly increased neutral zone (NZ) stiffness and NZ width but resulted in no change in the range of motion (ROM) or elastic zone stiffness. C45 and C56 IDP measured in the neutral position were significantly increased with application of FL. The change in IDP with increasing flexion rotation was not significantly affected by the application of FL, whereas the change in IDP with increasing extension rotation was significantly reduced by the application of FL. Application of FL did not appear to affect the specimen's quantity of motion (ROM) but did affect the quality (the shape of the curve). Regarding IDP, the effects of adding FL compression approximates the effect of the patient going from supine to a seated position (FL compression increased the IDP in the neutral position). The change in IDP with increasing flexion rotation was not affected by the application of FL, but the change in IDP with increasing extension rotation was, however, significantly reduced by the application of FL.
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Affiliation(s)
- Kevin M Bell
- Ferguson Laboratory for Spine Research, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, United States.
| | - Yiguo Yan
- Ferguson Laboratory for Spine Research, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, United States; Department of Spine Surgery, The First Affiliated Hospital of University of South China, Henyang City, Hunan Province, China
| | - Robert A Hartman
- Ferguson Laboratory for Spine Research, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, United States
| | - Joon Y Lee
- Ferguson Laboratory for Spine Research, Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, United States
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Adjacent Segment Disease After Cervical Spine Fusion: Evaluation of a 70 Patient Long-Term Follow-Up. Spine (Phila Pa 1976) 2018; 43:605-609. [PMID: 28816821 DOI: 10.1097/brs.0000000000002377] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A retrospective study of 70 patients undergoing surgical treatment for adjacent segment disease (ASD) after anterior cervical decompression and fusion (ACDF). OBJECTIVE To analyze the risk factors for the development of ASD in patients who underwent ACDF. SUMMARY OF BACKGROUND DATA ACDF has provided a high rate of clinical success for the cervical degenerative disc disease; nevertheless, adjacent segment degeneration has been reported as a complication at the adjacent level secondary to the rigid fixation. METHODS Between January 2005 and December 2012, 70 consecutive patients underwent surgery for ASD after ACDF in our institution. In all patients thorough clinical and radiological examination was performed preoperatively, postoperatively, and at the final follow-up. The clinical data included the Neck Disability Index (NDI) and the Visual Analogue Scale (VAS). The radiological evaluation included x-rays and magnetic resonance imaging (MRI) for all patients. The duration of follow up after the adjacent segment operation ranged from 3 to 10 years. RESULTS Surgery for ASD was performed after a mean period of 32 months from the primary ACDF. ASD occurred after single level ACDF in 54% of cases, most commonly after C5/6 fusion (28%). Risk factors for ASD were found to be preexisting radiological signs of degeneration at the primary surgery (74%) and bad sagittal profile after the primary ACDF (90%). CONCLUSION ASD occurred predominantly in the middle cervical region (C4-6); especially in patients with preexisting evidence of radiological degeneration in the adjacent segment at the time of primary cervical fusion, notably when this surgery failed to restore or maintain the cervical lordosis. LEVEL OF EVIDENCE 4.
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Lou J, Li Y, Wang B, Meng Y, Wu T, Liu H. In vitro biomechanical comparison after fixed- and mobile-core artificial cervical disc replacement versus fusion. Medicine (Baltimore) 2017; 96:e8291. [PMID: 29019902 PMCID: PMC5662325 DOI: 10.1097/md.0000000000008291] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
In vitro biomechanical analysis after cervical disc replacement (CDR) with a novel artificial disc prosthesis (mobile core) was conducted and compared with the intact model, simulated fusion, and CDR with a fixed-core prosthesis. The purpose of this experimental study was to analyze the biomechanical changes after CDR with a novel prosthesis and the differences between fixed- and mobile-core prostheses.Six human cadaveric C2-C7 specimens were biomechanically tested sequentially in 4 different spinal models: intact specimens, simulated fusion, CDR with a fixed-core prosthesis (Discover, DePuy), and CDR with a mobile-core prosthesis (Pretic-I, Trauson). Moments up to 2 Nm with a 75 N follower load were applied in flexion-extension, left and right lateral bending, and left and right axial rotation. The total range of motion (ROM), segmental ROM, and adjacent intradiscal pressure (IDP) were calculated and analyzed in 4 different spinal models, as well as the differences between 2 disc prostheses.Compared with the intact specimens, the total ROM, segmental ROM, and IDP at the adjacent segments showed no significant difference after arthroplasty. Moreover, CDR with a mobile-core prosthesis presented a little higher values of target segment (C5/6) and total ROM than CDR with a fixed-core prosthesis (P > .05). Besides, the difference in IDP at C4/5 after CDR with 2 prostheses was without statistical significance in all the directions of motion. However, the IDP at C6/7 after CDR with a mobile-core prosthesis was lower than CDR with a fixed-core prosthesis in flexion, extension, and lateral bending, with significant difference (P < .05), but not under axial rotation.CDR with a novel prosthesis was effective to maintain the ROM at the target segment and did not affect the ROM and IDP at the adjacent segments. Moreover, CDR with a mobile-core prosthesis presented a little higher values of target segment and total ROM, but lower IDP at the inferior adjacent segment than CDR with a fixed-core prosthesis.
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Affiliation(s)
- Jigang Lou
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan
| | - Yuanchao Li
- Department of Biomechanical Research Laboratory, Shanghai Jiao Tong University, Shanghai, China
| | - Beiyu Wang
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan
| | - Yang Meng
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan
| | - Tingkui Wu
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan
| | - Hao Liu
- Department of Orthopedics, West China Hospital, Sichuan University, Chengdu, Sichuan
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Zhang F, Xu HC, Yin B, Xia XL, Ma XS, Wang HL, Yin J, Shao MH, Lyu FZ, Jiang JY. Can an Endplate-conformed Cervical Cage Provide a Better Biomechanical Environment than a Typical Non-conformed Cage?: A Finite Element Model and Cadaver Study. Orthop Surg 2017; 8:367-76. [PMID: 27627721 DOI: 10.1111/os.12261] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Accepted: 03/21/2016] [Indexed: 11/28/2022] Open
Abstract
OBJECTIVES To evaluate the biomechanical characteristics of endplate-conformed cervical cages by finite element method (FEM) analysis and cadaver study. METHODS Twelve specimens (C2 -C7 ) and a finite element model (C3 -C7 ) were subjected to biomechanical evaluations. In the cadaver study, specimens were randomly assigned to intact (I), endplate-conformed (C) and non-conformed (N) groups with C4-5 discs as the treated segments. The morphologies of the endplate-conformed cages were individualized according to CT images of group C and the cages fabricated with a 3-D printer. The non-conformed cages were wedge-shaped and similar to commercially available grafts. Axial pre-compression loads of 73.6 N and moment of 1.8 Nm were used to simulate flexion (FLE), extension (EXT), lateral bending (LB) and axial rotation (AR). Range of motion (ROM) at C4-5 of each specimen was recorded and film sensors fixed between the cages and C5 superior endplates were used to detect interface stress. A finite element model was built based on the CT data of a healthy male volunteer. The morphologies of the endplate-conformed and wedge-shaped, non-conformed cervical cages were both simulated by a reverse engineering technique and implanted at the segment of C4-5 in the finite element model for biomechanical evaluation. Force loading and grouping were similar to those applied in the cadaver study. ROM of C4-5 in group I were recorded to validate the finite element model. Additionally, maximum cage-endplate interface stresses, stress distribution contours on adjoining endplates, intra-disc stresses and facet loadings at adjacent segments were measured and compared between groups. RESULTS In the cadaver study, Group C showed a much lower interface stress in all directions of motion (all P < 0.05) and the ROM of C4-5 was smaller in FLE-EXT (P = 0.001) but larger in AR (P = 0.017). FEM analysis produced similar results: the model implanted with an endplate-conformed cage presented a lower interface stress with a more uniform stress distribution than that implanted with a non-conformed cage. Additionally, intra-disc stress and facet loading at the adjacent segments were obviously increased in both groups C and N, especially those at the supra-jacent segments. However, stress increase was milder in group C than in group N for all directions of motion. CONCLUSIONS Endplate-conformed cages can decrease cage-endplate interface stress in all directions of motion and increase cervical stability in FLE-EXT. Additionally, adjacent segments are possibly protected because intra-disc stress and facet loading are smaller after endplate-conformed cage implantation. However, axial stability was reduced in group C, indicating that endplate-conformed cage should not be used alone and an anterior plate system is still important in anterior cervical discectomy and fusion.
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Affiliation(s)
- Fan Zhang
- Department of Orthopaedics, Huashan Hospital, Fudan University, Shanghai, China
| | - Hao-Cheng Xu
- Department of Orthopaedics, Huashan Hospital, Fudan University, Shanghai, China
| | - Bo Yin
- Department of Clinical Medicine, Shanghai Medical College, Fudan University, Shanghai, China
| | - Xin-Lei Xia
- Department of Orthopaedics, Huashan Hospital, Fudan University, Shanghai, China
| | - Xiao-Sheng Ma
- Department of Orthopaedics, Huashan Hospital, Fudan University, Shanghai, China
| | - Hong-Li Wang
- Department of Orthopaedics, Huashan Hospital, Fudan University, Shanghai, China
| | - Jun Yin
- Department of Orthopaedics, Huashan Hospital, Fudan University, Shanghai, China
| | - Ming-Hao Shao
- Department of Orthopaedics, Huashan Hospital, Fudan University, Shanghai, China
| | - Fei-Zhou Lyu
- Department of Orthopaedics, Huashan Hospital, Fudan University, Shanghai, China. .,Department of Orthopaedics, The Fifth People's Hospital of Shanghai, Fudan University, Shanghai, China.
| | - Jian-Yuan Jiang
- Department of Orthopaedics, Huashan Hospital, Fudan University, Shanghai, China
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Chang KE, Pham MH, Hsieh PC. Adjacent segment disease requiring reoperation in cervical total disc arthroplasty: A literature review and update. J Clin Neurosci 2017; 37:20-24. [DOI: 10.1016/j.jocn.2016.10.047] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 10/29/2016] [Indexed: 10/20/2022]
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Mo Z, Li Q, Jia Z, Yang J, Wong DWC, Fan Y. Biomechanical consideration of prosthesis selection in hybrid surgery for bi-level cervical disc degenerative diseases. 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 2016; 26:1181-1190. [PMID: 27652678 DOI: 10.1007/s00586-016-4777-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2016] [Revised: 09/01/2016] [Accepted: 09/09/2016] [Indexed: 01/24/2023]
Abstract
PURPOSE Hybrid surgery (HS) coupling total disc replacement and fusion has been increasingly applied for multilevel cervical disc diseases (CDD). However, selection of the optimal disc prosthesis for HS in an individual patient has not been investigated. This study aimed to distinguish the biomechanical performances of five widely used prostheses (Bryan, ProDisc-C, PCM, Mobi-C, and Discover) in HS for the treatment of bi-level CDD. METHODS A finite element model of healthy cervical spine (C3-C7) was developed, and five HS models using different disc prostheses were constructed by arthrodesis at C4-C5 and by arthroplasty at C5-C6. First, the rotational displacements in flexion (Fl), extension, axial rotation, and lateral bending in the healthy model under 1.0 Nm moments combined with 73.6 N follower load were achieved, and then the maximum rotations in each direction combined with the same follower load were applied in the surgical models following displacement control testing protocols. RESULTS The range of motion (ROM) of the entire operative and adjacent levels was close to that of the healthy spine for ball-in-socket prostheses, that is, ProDisc-C, Mobi-C, and Discover, in Fl. For Bryan and PCM, the ROM of the operative levels was less than that of the healthy spine in Fl and resulted in the increase in ROMs at the adjacent levels. Ball-in-socket prostheses produced similar reaction moments (92-99 %) in Fl, which were close to that of the healthy spine. Meanwhile, Bryan and PCM required greater moments (>130 %). The adjacent intradiscal pressures (IDPs) in the models of ball-in-socket prostheses were close to that of the healthy spine. Meanwhile, in the models of Bryan and PCM, the adjacent IDPs were 25 % higher than that of the ball-in-socket models. The maximum facet stress in the model of Mobi-C was the greatest among all prostheses, which was approximately two times that of the healthy spine. Moreover, Bryan produced the largest stress on the bone-implant interface, followed by PCM, Mobi-C, ProDisc-C, and Discover. CONCLUSION Each disc prosthesis has its biomechanical advantages and disadvantages in HS and should be selected on an individual patient basis. In general, ProDisc-C, Mobi-C, and Discover produced similar performances in terms of spinal motions, adjacent IDPs, and driving moments, whereas Bryan and PCM produced similar biomechanical performances. Therefore, HS with Discover, Bryan, and PCM may be suitable for patients with potential risk of facet joint degeneration, whereas HS with ProDisc-C, Mobi-C, and Discover may be suitable for patients with potential risk of vertebral osteoporosis.
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Affiliation(s)
- Zhongjun Mo
- National Research Center for Rehabilitation Technical Aids, Beijing, People's Republic of China.,Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, International Joint Research Center of Aerospace Biotechnology and Medical Engineering of Ministry of Science and Technology, School of Biological Science and Medical Engineering, Beihang University, Beijing, People's Republic of China
| | - Qi Li
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, International Joint Research Center of Aerospace Biotechnology and Medical Engineering of Ministry of Science and Technology, School of Biological Science and Medical Engineering, Beihang University, Beijing, People's Republic of China
| | - Zhiwei Jia
- Department of Orthopaedics, The 306th Hospital of People's Liberation Army, Beijing, People's Republic of China
| | - Jiemeng Yang
- National Research Center for Rehabilitation Technical Aids, Beijing, People's Republic of China
| | - Duo Wai-Chi Wong
- Interdisciplinary Division of Biomedical Engineering, The Hong Kong Polytechnic University, Hong Kong, SAR, People's Republic of China
| | - Yubo Fan
- National Research Center for Rehabilitation Technical Aids, Beijing, People's Republic of China. .,Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, International Joint Research Center of Aerospace Biotechnology and Medical Engineering of Ministry of Science and Technology, School of Biological Science and Medical Engineering, Beihang University, Beijing, People's Republic of China.
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A Biomechanical Analysis of an Artificial Disc With a Shock-absorbing Core Property by Using Whole-cervical Spine Finite Element Analysis. Spine (Phila Pa 1976) 2016; 41:E893-E901. [PMID: 26825785 DOI: 10.1097/brs.0000000000001468] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN A biomechanical comparison among the intact C2 to C7 segments, the C5 to C6 segments implanted with fusion cage, and three different artificial disc replacements (ADRs) by finite element (FE) model creation reflecting the entire cervical spine below C2. OBJECTIVE The aim of this study was to analyze the biomechanical changes in subaxial cervical spine after ADR and to verify the efficacy of a new mobile core artificial disc Baguera C that is designed to absorb shock. SUMMARY OF BACKGROUND DATA Scarce references could be found and compared regarding the cervical ADR devices' biomechanical differences that are consequently related to their different clinical results. METHODS One fusion device (CJ cage system, WINNOVA) and three different cervical artificial discs (Prodisc-C Nova (DePuy Synthes), Discocerv (Scient'x/Alphatec), Baguera C (Spineart)) were inserted at C5-6 disc space inside the FE model and analyzed. Hybrid loading conditions, under bending moments of 1 Nm along flexion, extension, lateral bending, and axial rotation with a compressive force of 50 N along the follower loading direction, were used in this study. Biomechanical behaviors such as segmental mobility, facet joint forces, and possible wear debris phenomenon inside the core were investigated. RESULTS The segmental motions as well as facet joint forces were exaggerated after ADR regardless of type of the devices. The Baguera C mimicked the intact cervical spine regarding the location of the center of rotation only during the flexion moment. It also showed a relatively wider distribution of the contact area and significantly lower contact pressure distribution on the core than the other two devices. A "lift off" phenomenon was noted for other two devices according to the specific loading condition. CONCLUSION The mobile core artificial disc Baguera C can be considered biomechanically superior to other devices by demonstrating no "lift off" phenomenon, and significantly lower contact pressure distribution on core. LEVEL OF EVIDENCE N/A.
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Abstract
Anterior cervical fusion has become a standard of care for numerous pathologic conditions of the cervical spine. However, subsequent development of clinically significant disc disease at levels adjacent to fused discs is a serious long-term complication of this procedure. As more patients live longer after surgery, it is foreseeable that adjacent segment pathology (ASP) will develop in increasing numbers of patients. Also, ASP has been studied more intensively with the recent popularity of motion preservation technologies like total disc arthroplasty. The true nature and scope of ASP remains poorly understood. The etiology of ASP is most likely multifactorial. Various factors including altered biomechanical stresses, surgical disruption of soft tissue and the natural history of cervical disc disease contribute to the development of ASP. General factors associated with disc degeneration including gender, age, smoking and sports may play a role in the development of ASP. Postoperative sagittal alignment and type of surgery are also considered potential causes of ASP. Therefore, a spine surgeon must be particularly careful to avoid unnecessary disruption of the musculoligamentous structures, reduced risk of direct injury to the disc during dissection and maintain a safe margin between the plate edge and adjacent vertebrae during anterior cervical fusion.
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Anderst W. Narrative review of the in vivo mechanics of the cervical spine after anterior arthrodesis as revealed by dynamic biplane radiography. J Orthop Res 2016; 34:22-30. [PMID: 26331480 DOI: 10.1002/jor.23042] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 08/28/2015] [Indexed: 02/04/2023]
Abstract
Arthrodesis is the standard of care for numerous pathologic conditions of the cervical spine and is performed over 150,000 times annually in the United States. The primary long-term concern after this surgery is adjacent segment disease (ASD), defined as new clinical symptoms adjacent to a previous fusion. The incidence of adjacent segment disease is approximately 3% per year, meaning that within 10 years of the initial surgery, approximately 25% of cervical arthrodesis patients require a second procedure to address symptomatic adjacent segment degeneration. Despite the high incidence of ASD, until recently, there was little data available to characterize in vivo adjacent segment mechanics during dynamic motion. This manuscript reviews recent advances in our knowledge of adjacent segment mechanics after cervical arthrodesis that have been facilitated by the use of dynamic biplane radiography. The primary observations from these studies are that current in vitro test paradigms often fail to replicate in vivo spine mechanics before and after arthrodesis, that intervertebral mechanics vary among cervical motion segments, and that joint arthrokinematics (i.e., the interactions between adjacent vertebrae) are superior to traditional kinematics measurements for identifying altered adjacent segment mechanics after arthrodesis. Future research challenges are identified, including improving the biofidelity of in vitro tests, determining the natural history of in vivo spine mechanics, conducting prospective longitudinal studies on adjacent segment kinematics and arthrokinematics after single and multiple-level arthrodesis, and creating subject-specific computational models to accurately estimate muscle forces and tissue loading in the spine during dynamic activities.
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Affiliation(s)
- William Anderst
- Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, Pennsylvania
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Bell KM, Yan Y, Debski RE, Sowa GA, Kang JD, Tashman S. Influence of varying compressive loading methods on physiologic motion patterns in the cervical spine. J Biomech 2015; 49:167-72. [PMID: 26708967 DOI: 10.1016/j.jbiomech.2015.11.045] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 11/17/2015] [Accepted: 11/21/2015] [Indexed: 10/22/2022]
Abstract
The human cervical spine supports substantial compressive load in-vivo arising from muscle forces and the weight of the head. However, the traditional in-vitro testing methods rarely include compressive loads, especially in investigations of multi-segment cervical spine constructs. Various methods of modeling physiologic loading have been reported in the literature including axial forces produced with inclined loading plates, eccentric axial force application, follower load, as well as attempts to individually apply/model muscle forces in-vitro. The importance of proper compressive loading to recreate the segmental motion patterns exhibited in-vivo has been highlighted in previous studies. However, appropriate methods of representing the weight of head and muscle loading are currently unknown. Therefore, a systematic comparison of standard pure moment with no compressive loading versus published and novel compressive loading techniques (follower load - FL, axial load - AL, and combined load - CL) was performed. The present study is unique in that a direct comparison to continuous cervical kinematics over the entire extension to flexion motion path was possible through an ongoing intra-institutional collaboration. The pure moment testing protocol without compression or with the application of follower load was not able to replicate the typical in-vivo segmental motion patterns throughout the entire motion path. Axial load or a combination of axial and follower load was necessary to mimic the in-vivo segmental contributions at the extremes of the extension-flexion motion path. It is hypothesized that dynamically altering the compressive loading throughout the motion path is necessary to mimic the segmental contribution patterns exhibited in-vivo.
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Affiliation(s)
- Kevin M Bell
- Ferguson Laboratory for Spine Research, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
| | - Yiguo Yan
- Ferguson Laboratory for Spine Research, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Richard E Debski
- Department of Bioengineering, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Gwendolyn A Sowa
- Department of Physical Medicine and Rehabilitation, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - James D Kang
- Ferguson Laboratory for Spine Research, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Scott Tashman
- Ferguson Laboratory for Spine Research, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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Costs of cervical disc replacement versus anterior cervical discectomy and fusion for treatment of single-level cervical disc disease: an analysis of the Blue Health Intelligence database for acute and long-term costs and complications. Spine (Phila Pa 1976) 2015; 40:521-9. [PMID: 25868092 DOI: 10.1097/brs.0000000000000822] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Retrospective review of prospectively collective administrative data. OBJECTIVE The purpose of this study was to determine the reoperation rates, adverse event rate, as well as the direct and follow-on costs of cervical disc arthroplasty (CDA) compared with anterior cervical discectomy and fusion (ACDF) in a "real-world" population of patients with single-level symptomatic cervical disc disease. SUMMARY OF BACKGROUND DATA Until very recently, there was a paucity of human clinical data to demonstrate that CDA lowers the rate of adjacent segment disease over ACDF. METHODS This was a retrospective, matched cohort analysis of a prospectively collected database of costs and outcomes for patients aged 18 to 60 years, who were continuously enrolled in a Blue Cross Plan contributing data to a claims database. Inclusion criteria were as follows: all patients who were treated surgically with either CDA or ACDF between January 2008 and December 2009, with single-level cervical pathology and claims reflecting at least 6 weeks of nonsurgical preoperative care without claims history of prior surgery. RESULTS There were 6635 ACDF patients and 327 CDA patients. There were no significant differences in the incidence of comorbidities or mean follow-up time (ACDF 25.7 mo vs. CDA 26.1 mo) between groups. By 36 months postoperatively, the reoperation rate was significantly increased in the ACDF group (10.5%) versus the CDA group (5.7%) (hazard ratio, P = 0.0214). The index surgery and 90-day global window costs were significantly lower in the CDA groups. At final follow-up, there was a statistically significant reduction in total costs paid by insurer in CDA patients (CDA $34,979 vs. ACDF $39,820). CONCLUSION Patients who underwent CDA for single-level degenerative disease had lower readmission rates, lower reoperation rates, and reduced index and total costs than those treated with ACDF. CDA was effective in reducing the monthly cost of care compared with ACDF. LEVEL OF EVIDENCE 2.
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TANG QIAOHONG, WANG LIZHEN, MO ZHONGJUN, LI QI, YAO JIE, DU CHENGFEI, FAN YUBO. BIOMECHANICAL ANALYSIS OF DIFFERENT PRODISC-C ARTHROPLASTY DESIGNS AFTER IMPLANTATION: A NUMERICAL SENSITIVITY STUDY. J MECH MED BIOL 2015. [DOI: 10.1142/s0219519415500074] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Ball-and-socket disc prostheses are the leading type of artificial disc replacement (ADR) and are typically used to treat degenerative cervical spine instability. Previous publications focused on the influence of different ProDisc-C design parameters in view of biomechanics. However, more beneficial data could be gathered if the implant was implanted prior to testing. Therefore, this study aimed to estimate the effect of different ProDisc-C arthroplasty designs and alignments when implanted at the C5-6 segment. This research can provide advice on the design of artificial discs as well as optimal placement. The geometry of the vertebrae was developed based on computed tomography (CT) images of a 32-year-old healthy male (170 cm height and 68 kg weight) with a slice thickness of 0.625 mm. A finite element (FE) model of intact C5–C6 segments including vertebrae and disc was developed and validated. A ball-and-socket artificial disc prosthesis model (ProDisc-C, Synthes) was implanted into the validated FE model. The curvature of the ProDisc-C prosthesis as well as the implanted position was varied. All models were loaded with a 74 N compressive force and pure moments of 1.8 Nm in flexion-extension, bilateral bending and axial torsion. The radius of the artificial disc influenced the ROM, facet joint force and capsule ligament tension only in flexion, while the position influenced these aspects in all loading conditions. The disc with a 6 mm radius had a greater ROM in flexion, and lower stress on the polyethylene (PE) insert without apparent stress concentrations, but it had a greater facet joint force and ligament tension compared to other radii. For all the designs, the implant position in the anterior–posterior direction had a significant influence on the disc biomechanics. Disc design and surgical procedure, such as implantation position, are important factors in postoperative rehabilitation, especially regarding the ROM in flexion/extension and implant stress. Thus, a suitable disc design should consider preserving an adequate range of motion (ROM) as well as a moderate facet joint force or stress, and proper implant positioning along the anterior–posterior direction should be monitored.
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Affiliation(s)
- QIAOHONG TANG
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, 100191 Beijing, P. R. China
- International Joint Research Center of Aerospace, Biotechnology and Medical Engineering, Ministry of Science and Technology of China, 100191 Beijing, P. R. China
| | - LIZHEN WANG
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, 100191 Beijing, P. R. China
- International Joint Research Center of Aerospace, Biotechnology and Medical Engineering, Ministry of Science and Technology of China, 100191 Beijing, P. R. China
| | - ZHONGJUN MO
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, 100191 Beijing, P. R. China
- International Joint Research Center of Aerospace, Biotechnology and Medical Engineering, Ministry of Science and Technology of China, 100191 Beijing, P. R. China
| | - QI LI
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, 100191 Beijing, P. R. China
- International Joint Research Center of Aerospace, Biotechnology and Medical Engineering, Ministry of Science and Technology of China, 100191 Beijing, P. R. China
| | - JIE YAO
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, 100191 Beijing, P. R. China
- International Joint Research Center of Aerospace, Biotechnology and Medical Engineering, Ministry of Science and Technology of China, 100191 Beijing, P. R. China
| | - CHENGFEI DU
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, 100191 Beijing, P. R. China
- International Joint Research Center of Aerospace, Biotechnology and Medical Engineering, Ministry of Science and Technology of China, 100191 Beijing, P. R. China
| | - YUBO FAN
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, School of Biological Science and Medical Engineering, Beihang University, 100191 Beijing, P. R. China
- International Joint Research Center of Aerospace, Biotechnology and Medical Engineering, Ministry of Science and Technology of China, 100191 Beijing, P. R. China
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Esmende SM, Daniels AH, Paller DJ, Koruprolu S, Palumbo MA, Crisco JJ. Cervical total disc replacement exhibits similar stiffness to intact cervical functional spinal units tested on a dynamic pendulum testing system. Spine J 2015; 15:162-7. [PMID: 25194516 DOI: 10.1016/j.spinee.2014.08.442] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 07/17/2014] [Accepted: 08/15/2014] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT The pendulum testing system is capable of applying physiologic compressive loads without constraining the motion of functional spinal units (FSUs). The number of cycles to equilibrium observed under pendulum testing is a measure of the energy absorbed by the FSU. OBJECTIVE To examine the dynamic bending stiffness and energy absorption of the cervical spine, with and without implanted cervical total disc replacement (TDR) under simulated physiologic motion. STUDY DESIGN A biomechanical cadaver investigation. METHODS Nine unembalmed, frozen human cervical FSUs from levels C3-C4 and C5-C6 were tested on the pendulum system with axial compressive loads of 25, 50, and 100 N before and after TDR implantation. Testing in flexion, extension, and lateral bending began by rotating the pendulum to 5°, resulting in unconstrained oscillatory motion. The number of rotations to equilibrium was recorded and the bending stiffness (Newton-meter/°) was calculated and compared for each testing mode. RESULTS In flexion/extension, with increasing compressive loading from 25 to 100 N, the average number of cycles to equilibrium for the intact FSUs increased from 6.6 to 19.1, compared with 4.1 to 12.7 after TDR implantation (p<.05 for loads of 50 and 100 N). In flexion, with increasing compressive loading from 25 to 100 N, the bending stiffness of the intact FSUs increased from 0.27 to 0.59 Nm/°, compared with 0.21 to 0.57 Nm/° after TDR implantation. No significant differences were found in stiffness between the intact FSU and the TDR in flexion/extension and lateral bending at any load (p<.05). CONCLUSIONS Cervical FSUs with implanted TDR were found to have similar stiffness, but had greater energy absorption than intact FSUs during cyclic loading with an unconstrained pendulum system. These results provide further insight into the biomechanical behavior of cervical TDR under approximated physiologic loading conditions.
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Affiliation(s)
- Sean M Esmende
- Department of Orthopaedic Surgery, Warren Alpert Medical School of Brown University, 593 Eddy St, Providence, RI 02906, USA.
| | - Alan H Daniels
- Department of Orthopaedic Surgery, Warren Alpert Medical School of Brown University, 593 Eddy St, Providence, RI 02906, USA
| | - David J Paller
- Department of Orthopaedic Surgery, Warren Alpert Medical School of Brown University, 593 Eddy St, Providence, RI 02906, USA
| | - Sarath Koruprolu
- Department of Orthopaedic Surgery, Warren Alpert Medical School of Brown University, 593 Eddy St, Providence, RI 02906, USA
| | - Mark A Palumbo
- Department of Orthopaedic Surgery, Warren Alpert Medical School of Brown University, 593 Eddy St, Providence, RI 02906, USA
| | - Joseph J Crisco
- Department of Orthopaedic Surgery, Warren Alpert Medical School of Brown University, 593 Eddy St, Providence, RI 02906, USA
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Calvert GC, Lawrence BD, Abtahi AM, Bachus KN, Brodke DS. Cortical screws used to rescue failed lumbar pedicle screw construct: a biomechanical analysis. J Neurosurg Spine 2014; 22:166-72. [PMID: 25478820 DOI: 10.3171/2014.10.spine14371] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECT Cortical trajectory screw constructs, developed as an alternative to pedicle screw fixation for the lumbar spine, have similar in vitro biomechanics. The possibility of one screw path having the ability to rescue the other in a revision scenario holds promise but has not been evaluated. The objective in this study was to investigate the biomechanical properties of traditional pedicle screws and cortical trajectory screws when each was used to rescue the other in the setting of revision. METHODS Ten fresh-frozen human lumbar spines were instrumented at L3-4, 5 with cortical trajectory screws and 5 with pedicle screws. Construct stiffness was recorded in flexion/extension, lateral bending, and axial rotation. The L-3 screw pullout strength was tested to failure for each specimen and salvaged with screws of the opposite trajectory. Mechanical stiffness was again recorded. The hybrid rescue trajectory screws at L-3 were then tested to failure. RESULTS Cortical screws, when used in a rescue construct, provided stiffness in flexion/extension and axial rotation similar to that provided by the initial pedicle screw construct prior to failure. The rescue pedicle screws provided stiffness similar to that provided by the primary cortical screw construct in flexion/extension, lateral bending, and axial rotation. In pullout testing, cortical rescue screws retained 60% of the original pedicle screw pullout strength, whereas pedicle rescue screws retained 65% of the original cortical screw pullout strength. CONCLUSIONS Cortical trajectory screws, previously studied as a primary mode of fixation, may also be used as a rescue option in the setting of a failed or compromised pedicle screw construct in the lumbar spine. Likewise, a standard pedicle screw construct may rescue a compromised cortical screw track. Cortical and pedicle screws each retain adequate construct stiffness and pullout strength when used for revision at the same level.
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Affiliation(s)
- Graham C Calvert
- Department of Orthopaedics, Orthopaedic Bioengineering Laboratory, University of Utah, Salt Lake City, Utah
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The effect of cervical posterior foraminotomy on segmental range of motion in the setting of total disc arthroplasty. Spine (Phila Pa 1976) 2014; 39:1572-7. [PMID: 24921846 DOI: 10.1097/brs.0000000000000469] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Human cadaveric biomechanical analysis. OBJECTIVE To investigate the effect on cervical spine segmental stability that results from a posterior foraminotomy after cervical disc arthroplasty (CDA). SUMMARY OF BACKGROUND DATA Posterior foraminotomy offers the ability to decompress cervical nerves roots while avoiding the need to extend a previous fusion or revise an arthroplasty to a fusion. However, the safety of a foraminotomy in the setting of CDA is unknown. METHODS Segmental nondestructive range of motion (ROM) was analyzed in 9 human cadaveric cervical spine specimens. After intact testing, each specimen was sequentially tested according to the following 4 experimental groups: group 1=C5-C6 CDA, group 2=C5-C6 CDA with unilateral C5-C6 foraminotomy, group 3=C5-C6 CDA with bilateral C5-C6 foraminotomy, and group 4=C5-C6 CDA with C5-C6 and C4-C5 bilateral foraminotomy. RESULTS No differences in ROM were found between the intact, CDA, and foraminotomy specimens at C4-C5 or C6-C7. There was a step-wise increase in C5-C6 axial rotation from the intact state (8°) to group 4 (12°), although the difference did not reach statistical significance. At C5-C6, the degree of lateral bending remained relatively constant. Flexion and extension at C5-C6 was significantly higher in the foraminotomy specimens, groups 2 (18.1°), 3 (18.6°), and 4 (18.2°), compared with the intact state, 11.2°. However, no ROM difference was found within foraminotomy groups (2-4) or between the foraminotomy groups and the CDA group (group 1), 15.3°. CONCLUSION Our results indicate that cervical stability is not significantly decreased by the presence, number, or level of posterior foraminotomies in the setting of CDA. The addition of foraminotomies to specimens with a pre-existing CDA resulted in small and insignificant increases in segmental ROM. Therefore, biomechanically, posterior foraminotomy/foraminotomies may be considered a safe and viable option in the setting of recurrent or adjacent level radiculopathy after cervical disc replacement. LEVEL OF EVIDENCE N/A.
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Song M, Zhang Z, Lu M, Zong J, Dong C, Ma K, Wang S. Four lateral mass screw fixation techniques in lower cervical spine following laminectomy: a finite element analysis study of stress distribution. Biomed Eng Online 2014; 13:115. [PMID: 25106498 PMCID: PMC4132205 DOI: 10.1186/1475-925x-13-115] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2014] [Accepted: 08/01/2014] [Indexed: 01/28/2023] Open
Abstract
Background Lateral mass screw fixation (LSF) techniques have been widely used for reconstructing and stabilizing the cervical spine; however, complications may result depending on the choice of surgeon. There are only a few reports related to LSF applications, even though fracture fixation has become a severe complication. This study establishes the three-dimensional finite element model of the lower cervical spine, and compares the stress distribution of the four LSF techniques (Magerl, Roy-Camille, Anderson, and An), following laminectomy -- to explore the risks of rupture after fixation. Method CT scans were performed on a healthy adult female volunteer, and Digital imaging and communication in medicine (Dicom) data was obtained. Mimics 10.01, Geomagic Studio 12.0, Solidworks 2012, HyperMesh 10.1 and Abaqus 6.12 software programs were used to establish the intact model of the lower cervical spines (C3-C7), a postoperative model after laminectomy, and a reconstructive model after applying the LSF techniques. A compressive preload of 74 N combined with a pure moment of 1.8 Nm was applied to the intact and reconstructive model, simulating normal flexion, extension, lateral bending, and axial rotation. The stress distribution of the four LSF techniques was compared by analyzing the maximum von Mises stress. Result The three-dimensional finite element model of the intact C3-C7 vertebrae was successfully established. This model consists of 503,911 elements and 93,390 nodes. During flexion, extension, lateral bending, and axial rotation modes, the intact model’s angular intersegmental range of motion was in good agreement with the results reported from the literature. The postoperative model after the three-segment laminectomy and the reconstructive model after applying the four LSF techniques were established based on the validated intact model. The stress distribution for the Magerl and Roy-Camille groups were more dispersive, and the maximum von Mises stress levels were lower than the other two groups in various conditions. Conclusion The LSF techniques of Magerl and Roy-Camille are safer methods for stabilizing the lower cervical spine. Therefore, these methods potentially have a lower risk of fixation fracture.
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Affiliation(s)
| | | | | | | | | | - Kai Ma
- Department of Orthopedics, The First Affiliated Hospital of Dalian Medical University, 222 Zhongshan Road, Dalian 116011, P,R, China.
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Hilibrand AS, McDonnell M. Commentary on: "Sagittal alignment as a predictor of clinical adjacent segment pathology requiring surgery after anterior cervical arthrodesis". Spine J 2014; 14:1235-6. [PMID: 24938909 DOI: 10.1016/j.spinee.2014.05.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 05/08/2014] [Indexed: 02/03/2023]
Affiliation(s)
- Alan S Hilibrand
- The Rothman Institute, Jefferson Medical College, 925 Chestnut St, 5th Floor, Philadelphia, PA 19107-4216, USA.
| | - Matthew McDonnell
- The Rothman Institute, Jefferson Medical College, 925 Chestnut St, 5th Floor, Philadelphia, PA 19107-4216, USA
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