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Zhang Z, Cao K, Zhong Y, Yang J, Chen S, Li G, Wang S, Wan Z. An in Vivo, Three-Dimensional (3D), Functional Centers of Rotation of the Healthy Cervical Spine. World Neurosurg 2024; 184:e203-e210. [PMID: 38266986 DOI: 10.1016/j.wneu.2024.01.086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 01/14/2024] [Accepted: 01/16/2024] [Indexed: 01/26/2024]
Abstract
OBJECTIVE This study examined cervical center of rotation (COR) positions in 7 postures using validated cone beam computed tomography (CBCT) combined with 3D-3D registration in healthy volunteers. METHODS CBCT scans were performed on 20 healthy volunteers in 7 functional positions, constructing a three-dimensional (3D) model. Images were registered to the neutral position using 3D-3D registration, allowing analysis of kinematic differences and rotational axes. COR measurements were obtained for each segment (C2/3 to C6/7) in each posture. RESULTS The CORs of C2/3 to C6/7 were predominantly posterior (-5.3 ± 3.8 ∼ -0.6 ± 1.2 mm) and superior (16.5 ± 6.0 ∼ 23.6 ± 3.2 mm) to the intervertebral disc's geometric center (GC) in flexion and extension. However, the C4/5 segment's COR was anterior to the GC (2.0 ± 9.8 mm) during flexion and close to it in the right-left direction. During left-right twisting, the CORs of C2/3-C6/7 were posterior (-21.8 ± 10.5 ∼-0.9 ± 0.8 mm) and superior (3.1 ± 7.5 ∼23.2 ± 3.6 mm) to the GCs in anterior-posterior and superior-inferior directions, without consistent right-left directionality. During left-right bending, each segment's COR was predominantly posterior (-25.2 ± 13.1 ∼-6.5 ± 9.9 mm) and superior (0.3 ± 12.5 ∼12.1 ± 5.1 mm) to the GC in anterior-posterior and superior-inferior directions, except for the C2/3 segment, located inferiorly (-5.9 ± 4.1 mm) in left bending. The right-left COR position varied across segments. CONCLUSIONS Our findings reveal segment-specific and posture-dependent COR variations. Notably, the CORs of C3/4, C4/5, and C5/6 consistently align near the intervertebral disc's GC at different postures, supporting their suitability for total disc replacement surgery within the C3/4 to C5/6 segments.
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Affiliation(s)
- Zizhen Zhang
- The Orthopedic Hospital, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
| | - Kai Cao
- The Orthopedic Hospital, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
| | - Yanlong Zhong
- The Orthopedic Hospital, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
| | - Jie Yang
- The Orthopedic Hospital, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
| | - Shaofeng Chen
- The Orthopedic Hospital, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China
| | - Guoan Li
- Department of Orthopaedic Surgery, Orthopaedic Bioengineering Research Center, Newton-Wellesley Hospital, Harvard Medical School, Newton, Massachusetts, USA
| | - Shaobai Wang
- Key Laboratory of Exercise and Health Sciences of Ministry of Education, School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Zongmiao Wan
- The Orthopedic Hospital, The First Affiliated Hospital, Jiangxi Medical College, Nanchang University, Nanchang, Jiangxi, China.
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Wahbeh JM, Hookasian E, Lama J, Alam L, Park S, Sangiorgio SN, Ebramzadeh E. An additively manufactured model for preclinical testing of cervical devices. JOR Spine 2024; 7:e1285. [PMID: 38222806 PMCID: PMC10782067 DOI: 10.1002/jsp2.1285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 08/29/2023] [Accepted: 09/06/2023] [Indexed: 01/16/2024] Open
Abstract
Purpose Composite models have become commonplace for the assessment of fixation and stability of total joint replacements; however, there are no comparable models for the cervical spine to evaluate fixation. The goal of this study was to create the framework for a tunable non-homogeneous model of cervical vertebral body by identifying the relationships between strength, in-fill density, and lattice structure and creating a final architectural framework for specific strengths to be applied to the model. Methods The range of material properties for cervical spine were identified from literature. Using additive manufacturing software, rectangular prints with three lattice structures, gyroid, triangle, zig-zag, and a range of in-fill densities were 3D-printed. The compressive and shear strengths for all combinations were calculated in the axial and coronal planes. Eleven unique vertebral regions were selected to represent the distribution of density. Each bone density was converted to strength and subsequently correlated to the lattice structure and in-fill density with the desired material properties. Finally, a complete cervical vertebra model was 3D-printed to ensure sufficient print quality. Results Materials testing identified a relationship between in-fill densities and strength for all lattice structures. The axial compressive strength of the gyroid specimens ranged from 1.5 MPa at 10% infill to 31.3 MPa at 100% infill and the triangle structure ranged from 2.7 MPa at 10% infill to 58.4 MPa at 100% infill. Based on these results, a cervical vertebra model was created utilizing cervical cancellous strength values and the corresponding in-fill density and lattice structure combination. This model was then printed with 11 different in-fill densities ranging from 33% gyroid to 84% triangle to ensure successful integration of the non-homogeneous in-fill densities and lattice structures. Conclusions The findings from this study introduced a framework for using additive manufacturing to create a tunable, customizable biomimetic model of a cervical vertebra.
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Affiliation(s)
- Jenna M. Wahbeh
- The J. Vernon Luck, Sr., M.D. Orthopaedic Research CenterLuskin Orthopaedic Institute for ChildrenLos AngelesCaliforniaUSA
- Department of BioengineeringUCLALos AngelesCaliforniaUSA
| | - Erika Hookasian
- The J. Vernon Luck, Sr., M.D. Orthopaedic Research CenterLuskin Orthopaedic Institute for ChildrenLos AngelesCaliforniaUSA
- Department of BioengineeringUCLALos AngelesCaliforniaUSA
| | - John Lama
- The J. Vernon Luck, Sr., M.D. Orthopaedic Research CenterLuskin Orthopaedic Institute for ChildrenLos AngelesCaliforniaUSA
- Department of BioengineeringUCLALos AngelesCaliforniaUSA
| | - Labiba Alam
- The J. Vernon Luck, Sr., M.D. Orthopaedic Research CenterLuskin Orthopaedic Institute for ChildrenLos AngelesCaliforniaUSA
- Department of BioengineeringUCLALos AngelesCaliforniaUSA
| | - Sang‐Hyun Park
- The J. Vernon Luck, Sr., M.D. Orthopaedic Research CenterLuskin Orthopaedic Institute for ChildrenLos AngelesCaliforniaUSA
- Department of Orthopaedic SurgeryUCLALos AngelesCaliforniaUSA
| | - Sophia N. Sangiorgio
- The J. Vernon Luck, Sr., M.D. Orthopaedic Research CenterLuskin Orthopaedic Institute for ChildrenLos AngelesCaliforniaUSA
- Department of BioengineeringUCLALos AngelesCaliforniaUSA
- Department of Orthopaedic SurgeryUCLALos AngelesCaliforniaUSA
| | - Edward Ebramzadeh
- The J. Vernon Luck, Sr., M.D. Orthopaedic Research CenterLuskin Orthopaedic Institute for ChildrenLos AngelesCaliforniaUSA
- Department of Orthopaedic SurgeryUCLALos AngelesCaliforniaUSA
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Abudouaini H, Wu T, Meng Y, Ding C, Liu H, Beiyu W. Biomechanical properties of a novel cervical spine implant with elastic deformation: a cadaveric study. Front Bioeng Biotechnol 2023; 11:1214877. [PMID: 37711451 PMCID: PMC10497878 DOI: 10.3389/fbioe.2023.1214877] [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: 04/30/2023] [Accepted: 08/15/2023] [Indexed: 09/16/2023] Open
Abstract
Introduction: Anterior cervical discectomy and fusion (ACDF) is a most frequently used surgical procedure for treating cervical radiculopathy and myelopathy. However, there is concern about the high adjacent segment degeneration (ASD) rate after ACDF surgery. We creatively designed an elastically deformable cervical implant to reduce the postoperative stress concentration. In this study, we aimed to investigate the biomechanical performance of this novel cervical implant and compare it with the commonly used cervical devices. Methods: Biomechanical test was conducted on twelve fresh-frozen human cadaveric cervical spines (C2-C7) and randomly divided into four groups according to implant types: intact group, Zero-P VA fusion (ACDF) group, the novel cervical implant group and Pretic-I artificial cervical disc (ACDR) group. An optical tracking system was used to evaluate the segmental range of motion (ROM) of the C4/C5, C5/C6, and C6/C7 segments and micro pressure sensor was used to record the maximum facet joint pressure (FJP), maximum intradiscal pressure (IDP) at the C4-5 and C6-7 segments. Results: There were no significant differences in the ROM of adjacent segments between the groups. Compared with the intact group, the ACDR group essentially retained the ROM of the operated segment. The novel cervical implant decrease some ROM of the operated segment, but it was still significantly higher than in the fusion group; The maximum FJP and IDP at the adjacent segments in the ACDF group were significantly higher than those values in the other groups, and there were no differences in the other groups. Conclusion: While the newly developed elastically deformable cervical implant does not completely maintain ROM like the artificial cervical disc, it surpasses the fusion device with regards to biomechanical attributes. After further refinement, this novel implant may be suitable for patients who are prone to severe adjacent segment degeneration after fusion surgery but no indication for artificial cervical disc surgery.
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Affiliation(s)
- Haimiti Abudouaini
- Department of Orthopedic Surgery, West China Hospital, Sichuan University, Chengdu, China
- Department of Spine Surgery, Honghui Hospital, Xi’an Jiaotong University, Xi’an, China
| | - Tingkui Wu
- Department of Orthopedic Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Yang Meng
- Department of Orthopedic Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Chen Ding
- Department of Orthopedic Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Hao Liu
- Department of Orthopedic Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Wang Beiyu
- Department of Orthopedic Surgery, West China Hospital, Sichuan University, Chengdu, China
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Kontakis M, Marques C, Löfgren H, Mosavi F, Skeppholm M, Olerud C, MacDowall A. Artificial disc replacement and adjacent-segment pathology: 10-year outcomes of a randomized trial. J Neurosurg Spine 2021:1-9. [PMID: 34920425 DOI: 10.3171/2021.9.spine21904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 09/27/2021] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Artificial disc replacement (ADR) is designed to preserve motion and thus protect against adjacent-segment pathology (ASP) and act as an alternative treatment to fusion surgery. The question remains, how well do ADR devices perform after 10 years of follow-up compared with fusion surgery in terms of patient satisfaction, sustainability, and protection against ASP? METHODS This was the 10-year follow-up study of 153 participants who underwent ADR or fusion surgery after anterior decompression due to cervical degenerative radiculopathy (ISRCTN registration no. 44347115). Scores on the Neck Disability Index (NDI), EQ-5D, and visual analog scale for neck and arm pain were obtained from the Swedish Spine Registry and analyzed using ANCOVA. Information about secondary surgical procedures was collected from medical records and presented as Kaplan-Meier curves. MRI and flexion-extension radiography were performed, and ASP was graded according to the Miyazaki classification system. RESULTS Ten participants were lost to follow-up, which left 143 participants (80 underwent ADR and 65 underwent anterior cervical discectomy and fusion). There were no differences between groups in terms of patient-reported outcome measures (10-year difference in NDI scores 1.7 points, 95% CI -5.1 to 8.5, p = 0.61). Nineteen (24%) participants in the ADR group compared with 9 (14%) in the fusion group underwent secondary surgical procedures. The higher reoperation rate of the ADR group was mainly due to 11 female participants with device loosening. The rates of reoperation due to ASP were similar between groups, which was confirmed with MRI assessment of ASP that also showed no differences between the groups (p = 0.21). CONCLUSIONS This was the first 10-year follow-up study to compare ADR with fusion surgery and to provide MRI information for the assessment of ASP. The authors found no benefit of ADR over fusion surgery after anterior decompression for cervical degenerative radiculopathy.
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Affiliation(s)
- Michael Kontakis
- 1Department of Surgical Sciences, Uppsala University Hospital, Uppsala, Sweden
| | - Catarina Marques
- 1Department of Surgical Sciences, Uppsala University Hospital, Uppsala, Sweden
| | - Håkan Löfgren
- 2Neuro-Orthopaedic Center, Jönköping, and Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Firas Mosavi
- 3Department of Radiology, Uppsala University Hospital, Uppsala, Sweden; and
| | - Martin Skeppholm
- 4Department of Learning, Informations, Management and Ethics (LIME), Medical Management Center, Health Economics and Health Evaluation Research Group, Karolinska Institutet, Stockholm and Center for Spine Surgery in Stockholm, Sophiahemmets Sjukhus, Stockholm, Sweden
| | - Claes Olerud
- 1Department of Surgical Sciences, Uppsala University Hospital, Uppsala, Sweden
| | - Anna MacDowall
- 1Department of Surgical Sciences, Uppsala University Hospital, Uppsala, Sweden
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Wang XF, Meng Y, Liu H, Wang BY, Hong Y. The impact of different artificial disc heights during total cervical disc replacement: an in vitro biomechanical study. J Orthop Surg Res 2021; 16:12. [PMID: 33407705 PMCID: PMC7789724 DOI: 10.1186/s13018-020-02157-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 12/14/2020] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND The principles of choosing an appropriate implant height remain controversial in total cervical disc replacement (TDR). By performing an in vitro biomechanical study and exploring the biomechanical impact of implant height on facet joint and motion function, the study aimed to offer valid proposals regarding implant height selection during TDR. METHODS A total of 6 fresh-frozen male cadaveric cervical spines (C2-C7) with 5 mm intervertebral disc height at C5/6 level were enrolled in the study. Specimens with the intact condition and with different height artificial discs were tested. Facet joint pressures and range of motion under each condition were recorded using a specialized machine. RESULTS The artificial disc heights that were involved in this study were 5 mm, 6 mm, and 7 mm. The range of motion decreased along with the increment of implant height, while facet joint pressure showed an opposite trend. Specimens with a 5 mm implant height could provide a similar range of motion (11.8° vs. 12.2° in flexion-extension, 8.7° vs. 9.0° in rotation, 7.9° vs. 8.2° in lateral bending) and facet joint pressure (27.8 psi vs. 25.2 psi in flexion, 59.7 psi vs. 58.9 psi in extension, 24.0 psi vs. 22.7 psi in rotation, 32.0 psi vs. 28.8 psi in lateral bending) compared with intact specimens. Facet joint pressure of specimens with 6 mm implant height (≥ 1 mm in height) increased during flexion at the C5-6 segment (30.4 psi vs. 25.2 psi, P = 0.076). However, specimens with 7 mm implant height (≥ 2 mm in height) showed a significant reduction in motion (9.5° vs. 12.2° in flexion-extension, P < 0.001) and increment of facet joint pressure at C5-6 segment (44.6 psi vs. 25.2 psi in flexion, 90.3 psi vs. 58.9 psi in extension, P < 0.0001) and adjacent segments. CONCLUSIONS This study suggested that an appropriate artificial disc height can achieve near-normal biomechanical properties and is recommended. We should be very cautious when using artificial discs ≥ 1 mm in height compared to normal. However, implants ≥ 2 mm in height compared to normal significantly increased the facet joint pressure and decreased the range of motion; therefore, it should not be used in clinical practice.
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Affiliation(s)
- Xiao-Fei Wang
- Department of Orthopaedic Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Xiang, Chengdu, 610041, Sichuan, China
| | - Yang Meng
- Department of Orthopaedic Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Xiang, Chengdu, 610041, Sichuan, China
| | - Hao Liu
- Department of Orthopaedic Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Xiang, Chengdu, 610041, Sichuan, China.
| | - Bei-Yu Wang
- Department of Orthopaedic Surgery, West China Hospital, Sichuan University, No. 37 Guo Xue Xiang, Chengdu, 610041, Sichuan, China
| | - Ying Hong
- Department of Anesthesia and Operation Room/West China School of Nursing, West China Hospital, Sichuan University, No. 37 Guo Xue Xiang, Chengdu, 610041, Sichuan, China.
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Biomechanical response of a novel intervertebral disc prosthesis using functionally graded polymers: A finite element study. J Mech Behav Biomed Mater 2019; 94:288-297. [DOI: 10.1016/j.jmbbm.2019.02.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 02/05/2019] [Accepted: 02/19/2019] [Indexed: 12/18/2022]
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Zhao X, Yuan W. Biomechanical analysis of cervical range of motion and facet contact force after a novel artificial cervical disc replacement. Am J Transl Res 2019; 11:3109-3115. [PMID: 31217880 PMCID: PMC6556652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2019] [Accepted: 03/03/2019] [Indexed: 06/09/2023]
Abstract
An ideal implantation of artificial cervical disc replacement (ACDR) prosthesis should preserve the cervical biomechanics and maintain normal cervical biomechanics. In this study, we designed a novel prosthesis based on the physiological curvature of the cervical endplate, and conducted an in vitro test with cadaveric cervical specimens to study its effect on cervical range of motion (ROM) and facet contact force. Eighteen cadaveric cervical specimens (C2-C7) were evaluated with a 50 N follower load and a moment of ± 2.0 N-m. Testing conditions were as follows: control (group 1), C5-C6 ACDR with a novel prosthesis (group 2), C5-C6 ACDR with the Prestige LP prosthesis (group 3) and C5-C6 cervical discectomy and fusion (ACDF) with cage internal fixation (group 4). The range of motion (ROM) of all segments and facet joint contact force were measured and analyzed. The results showed that there was no significant difference among the group 1, 2 and 3 in terms of ROM (P>0.05). The ROM of C5-C6 in the group 4 showed a significant decrease compared with the group 1, 2, and 3 (P<0.05). The group 2 had a similar facet joint force with the group 1, and there is no statistical difference among the group 1, 2 and 3 (P>0.05). The facet joint force of C5-C6 in the group 4 reduced significantly compared with the other groups (P<0.05). In conclusion, both novel cervical prosthesis and Prestige LP could better preserve the normal cervical ROM and maintain facet joint force than ACDF.
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Affiliation(s)
- Xin Zhao
- Department of Operation Room, First Hospital of China Medical UniversityShenyang, Liaoning, China
| | - Wei Yuan
- Department of Orthopedics, First Hospital of China Medical UniversityShenyang, Liaoning, China
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