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Subramanian T, Song J, Kim YE, Maayan O, Kamil R, Shahi P, Shinn D, Dalal S, Araghi K, Asada T, Amen TB, Sheha E, Dowdell J, Qureshi S, Iyer S. Predictors of Nonhome Discharge After Cervical Disc Replacement. Clin Spine Surg 2024; 37:E324-E329. [PMID: 38954743 DOI: 10.1097/bsd.0000000000001604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 01/22/2024] [Indexed: 07/04/2024]
Abstract
STUDY DESIGN Retrospective review of a national database. OBJECTIVE The aim of this study was to identify the factors that increase the risk of nonhome discharge after CDR. SUMMARY OF BACKGROUND DATA As spine surgeons continue to balance increasing surgical volume, identifying variables associated with patient discharge destination can help expedite postoperative placement and reduce unnecessary length of stay. However, no prior study has identified the variables predictive of nonhome patient discharge after cervical disc replacement (CDR). METHODS The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was queried for patients who underwent primary 1-level or 2-level CDR between 2011 and 2020. Multivariable Poisson regression with robust error variance was employed to identify the predictors for nonhome discharge destination following surgery. RESULTS A total of 7276 patients were included in this study, of which 94 (1.3%) patients were discharged to a nonhome destination. Multivariable regression revealed older age (OR: 1.076, P <0.001), Hispanic ethnicity (OR: 4.222, P =0.001), BMI (OR: 1.062, P =0.001), ASA class ≥3 (OR: 2.562, P =0.002), length of hospital stay (OR: 1.289, P <0.001), and prolonged operation time (OR: 1.007, P <0.001) as predictors of nonhome discharge after CDR. Outpatient surgery setting was found to be protective against nonhome discharge after CDR (OR: 0.243, P <0.001). CONCLUSIONS Age, Hispanic ethnicity, BMI, ASA class, prolonged hospital stay, and prolonged operation time are independent predictors of nonhome discharge after CDR. Outpatient surgery setting is protective against nonhome discharge. These findings can be utilized to preoperatively risk stratify expected discharge destination, anticipate patient discharge needs postoperatively, and expedite discharge in these patients to reduce health care costs associated with prolonged length of hospital stay. LEVEL OF EVIDENCE IV.
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Affiliation(s)
| | | | | | - Omri Maayan
- Hospital for Special Surgery
- Weill Cornell Medicine, New York, NY
| | | | | | - Daniel Shinn
- Hospital for Special Surgery
- Weill Cornell Medicine, New York, NY
| | | | | | | | | | - Evan Sheha
- Hospital for Special Surgery
- Weill Cornell Medicine, New York, NY
| | - James Dowdell
- Hospital for Special Surgery
- Weill Cornell Medicine, New York, NY
| | - Sheeraz Qureshi
- Hospital for Special Surgery
- Weill Cornell Medicine, New York, NY
| | - Sravisht Iyer
- Hospital for Special Surgery
- Weill Cornell Medicine, New York, NY
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Altorfer FCS, Avrumova F, Abjornson C, Lebl DR. Cervical Disk Arthroplasty: Updated Considerations of an Evolving Technology. J Am Acad Orthop Surg 2024:00124635-990000000-01051. [PMID: 39029103 DOI: 10.5435/jaaos-d-24-00127] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 06/19/2024] [Indexed: 07/21/2024] Open
Abstract
For years, anterior cervical diskectomy and fusion has been considered the benchmark for patients with cervical radiculopathy/myelopathy. However, concerns regarding adjacent segment pathology have promoted the popularity of cervical disk arthroplasty (CDA) with its motion-preserving properties. To replicate the natural cervical disk's six degrees of freedom and compressibility in cervical spine implants, designers need to carefully consider the level of constraint for stability and material selection. Recent CDA designs have incorporated strategies to facilitate unrestricted or semirestricted motion, deploying various articulating components and materials with distinct wear and compressibility properties. To optimize outcomes, patient selection considering additional degeneration of the cervical spine is critical. Clinical long-term studies have been reported in industry-funded FDA investigational device exemption and nonindustry-funded data for one-level and two-level CDA. There are limited data available on three-level and four-level CDA. Adverse events such as heterotopic ossification, osteolysis, migration, subsidence, and failure have been described, where analysis from explanted devices yields insight into in vivo wear and impingement performance. CDA has shown short-term cost advantages, such as decreased procedural expenses. Nonetheless, long-term analysis is necessary to assess possible economic tradeoffs. Advancements in designs may lead to improved implant longevity while evidence-based decision making will guide and responsibly manage the rapid advancement in CDA technology.
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Vogt M, Mehren C, Hackenbroch C, Wilke HJ. Influence of cervical total disc replacement on motion in the target and adjacent segments. Spine J 2024; 24:1313-1322. [PMID: 38301903 DOI: 10.1016/j.spinee.2024.01.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 01/10/2024] [Accepted: 01/22/2024] [Indexed: 02/03/2024]
Abstract
BACKGROUND CONTEXT The motion limitation after cervical discectomy and fusion alters the spine´s kinematics. Unphysiological strains may be the result and possible explanation for adjacent segment degeneration. Alterations to cervical kinematics due to cervical total disc replacement (TDR), especially two-level, are still under investigated. PURPOSE To investigate cervical motion including coupled motions after one-level and two-level TDR in the treated and also the adjacent segments. STUDY DESIGN An in-vitro study using pure moment loading of human donor spines. METHODS Seven fresh frozen human cervical spine specimens (C4-T1, median age 46 with range 19-60 years, four female) were included in this study. Specimens were tested in the intact condition first, followed by one-level TDR at C5-6 which was subsequently extended one level further caudal (C5-7). Each specimen was quasistatically loaded with pure moments up to 1.5 Nm in flexion/extension (FE), lateral bending (LB), and axial rotation (AR) in a universal spine tester for 3.5 cycles at 1 °/s. During the tests three dimensional motion tracking was performed for each vertebral body individually. From that, the primary and coupled ROM of each spinal level during the third full cycle of motion were evaluated. Nonparametric statistical analysis was performed using a Friedman-test and post hoc correction with Dunn-Bonferroni-tests (p<.05). Ethics approval was obtained in advance. RESULTS In FE, one-level TDR (C5-6) moderately increased primary FE in all four segments, but only significantly at the cranial adjacent level C4-5. Additional TDR at C6-7 further increased the ROM at the target segment without much influence on the other levels. Increasing implant height at C6-7 partially counteracted the increased FE. Coupled motions were minimal in all test conditions at all levels. In LB, coupled AR was observed in all test conditions at all levels. One-level TDR decreased primary LB at the target segment C5-6 significantly, without much influence on the other levels. Extending TDR to C6-7 decreased ROM in the target segment but without gaining statistical significance. Increasing implant height at C6-7 further decreased primary LB at the target segment, still without significance. Notably, coupled AR was significantly decreased at the cranial adjacent segment C4-5 compared to the intact condition. In AR, coupled LB was observed in all test conditions at the levels C4-5, C5-6, and C6-7, while the transition level to the thoracic spine C7-T1 showed only little coupled LB. Both one-level and two-level TDR showed little influence on primary AR or coupled motions at any level. Only after increasing implant height at C6-7 was the motion of the caudally adjacent level C7-T1 significantly altered. CONCLUSION Evaluating primary FE, LB, and AR together with the associated coupled motions revealed widespread influence of cervical TDR not only on the motion of the treated level but also at the adjacent segments. The influence of two-level TDR is more widespread and involves more levels than one-level TDR. CLINICAL SIGNIFICANCE The prevention of unphysiological strains due to altered kinematics after cervical fusion, which could possibly explain adjacent segment degeneration, were a driving factor in the development of TDR. These experimental findings suggest cervical TDR influences the whole cervical spine, not only the treated segment. The effect becomes more extensive, involving more levels and motion directions, after two-level than after one-level TDR.
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Affiliation(s)
- Morten Vogt
- Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre Ulm, University of Ulm, Helmholtzstr. 14, 89081 Ulm, Germany
| | - Christoph Mehren
- Spine Center, Schoen Clinic Munich-Harlaching, Harlachinger Str. 51, 81547 Munich, Germany; Academic Teaching Hospital of the Ludwig-Maximilians-University (LMU), Marchioninistr. 15, 81377 Munich, Germany; Academic Teaching Hospital of the Paracelsus Medical University (PMU), Strubergasse 21, 5020 Salzburg, Austria
| | - Carsten Hackenbroch
- Department of Diagnostic and Interventional Radiology and Neuroradiology, German Armed Forces Hospital of Ulm, Oberer Eselsberg 40, 89081 Ulm, Germany; Department of Diagnostic and Interventional Radiology, University Hospital Ulm, Albert-Einstein-Allee 23, 89081 Ulm, Germany
| | - Hans-Joachim Wilke
- Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre Ulm, University of Ulm, Helmholtzstr. 14, 89081 Ulm, Germany.
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Zavras AG, Acosta JR, Holmberg KJ, Semenza NC, Jayamohan HR, Cheng BC, Altman DT, Sauber RD. Effect of device constraint: a comparative network meta-analysis of ACDF and cervical disc arthroplasty. Spine J 2024:S1529-9430(24)00267-5. [PMID: 38843960 DOI: 10.1016/j.spinee.2024.05.016] [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] [Received: 04/04/2024] [Revised: 05/27/2024] [Accepted: 05/28/2024] [Indexed: 07/12/2024]
Abstract
BACKGROUND CONTEXT Clinical trials have demonstrated that cervical disc arthroplasty (CDA) is an effective and safe alternative treatment to anterior cervical discectomy and fusion (ACDF) for cervical degenerative disc disease in the appropriately indicated patient population. Various devices for CDA exist, differing in the level of device constraint. PURPOSE To investigate outcomes following Anterior Cervical Discectomy and Fusion (ACDF) versus CDA stratified based on the level of device constraint: Constrained, Semiconstrained, and Unconstrained. STUDY DESIGN Systematic review and network meta-analysis. PATIENT SAMPLE 2,932 CDA patients (979 Constrained, 1,214 Semiconstrained, 739 Unconstrained) and 2,601 ACDF patients from 41 studies that compared outcomes of patients undergoing CDA or ACDF at a single level at a minimum of 2 years follow-up. OUTCOME MEASURES Outcomes of interest included the development of adjacent segment degeneration (ASD), index and adjacent segment reoperation rates, range of motion (ROM), high-grade heterotopic ossification (HO, McAfee Grades 3/4), and patient-reported outcomes (NDI/VAS). METHODS CDA devices were grouped based on the degrees of freedom (DoF) allowed by the device, as either Constrained (3 DoF), Semiconstrained (4 or 5 DoF), or Unconstrained (6 DoF). A random effects network meta-analysis was conducted using standardized mean differences (SMD) and log relative risk (RR) were used to analyze continuous and categorical data, respectively. RESULTS Semiconstrained (p=.03) and Unconstrained CDA (p=.01) demonstrated a significantly lower risk for ASD than ACDF. All levels of CDA constraint demonstrated a significantly lower risk for subsequent adjacent segment surgery than ACDF (p<.001). Semiconstrained CDA also demonstrated a significantly lower risk for index level reoperation than both ACDF and Constrained CDA (p<.001). Unconstrained devices retained significantly greater ROM than both Constrained and Semiconstrained CDA (p<.001). As expected, all levels of device constraint retained significantly greater ROM than ACDF (p<.001). Constrained and Unconstrained devices both demonstrated significantly lower levels of disability on NDI than ACDF (p=.02). All levels of device constraint demonstrated significantly less neck pain than ACDF (p<.05), while Unconstrained CDA had significantly less arm pain than ACDF (p=.02) at final follow-up greater than 2 years. CONCLUSION Cervical Disc Arthroplasty, particularly the unconstrained and semiconstrained designs, appears to be more effective than ACDF in reducing the risk of adjacent segment degeneration and the need for further surgeries, while also allowing for greater range of motion and better patient-reported outcomes. Less constrained CDA conferred a lower risk for index level reoperation, while also retaining more range of motion than more constrained devices.
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Affiliation(s)
- Athan G Zavras
- Department of Orthopaedic Surgery, Allegheny General Hospital, Pittsburgh, PA, USA.
| | - Jonathan R Acosta
- Department of Orthopaedic Surgery, Allegheny General Hospital, Pittsburgh, PA, USA
| | - Kyle J Holmberg
- Department of Orthopaedic Surgery, Allegheny General Hospital, Pittsburgh, PA, USA
| | - Nicholas C Semenza
- Department of Orthopaedic Surgery, Allegheny General Hospital, Pittsburgh, PA, USA
| | | | - Boyle C Cheng
- Department of Orthopaedic Surgery, Allegheny General Hospital, Pittsburgh, PA, USA
| | - Daniel T Altman
- Department of Orthopaedic Surgery, Allegheny General Hospital, Pittsburgh, PA, USA
| | - Ryan D Sauber
- Department of Orthopaedic Surgery, Allegheny General Hospital, Pittsburgh, PA, USA
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Patwardhan AG, Havey RM, Phillips FM, Zigler JE, Coric D, Guyer R, Lanman T, Muriuki MG. Prosthesis design and likelihood of achieving physiological range of motion after cervical disc arthroplasty: analysis of range of motion data from 1,173 patients from 7 IDE clinical trials. Spine J 2024; 24:969-978. [PMID: 38290621 DOI: 10.1016/j.spinee.2024.01.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Revised: 01/11/2024] [Accepted: 01/22/2024] [Indexed: 02/01/2024]
Abstract
BACKGROUND CONTEXT The functional goals of cervical disc arthroplasty (CDA) are to restore enough range of motion (ROM) to reduce the risk of accelerated adjacent segment degeneration but limit excessive motion to maintain a biomechanically stable index segment. This motion-range is termed the "Physiological mobility range." Clinical studies report postoperative ROM averaged over all study subjects but they do not report what proportion of reconstructed segments yield ROM in the Physiological mobility range following CDA surgery. PURPOSE To calculate the proportion of reconstructed segments that yield flexion-extension ROM (FE-ROM) in the Physiological mobility range (defined as 5°-16°) by analyzing the 24-month postoperative data reported by clinical trials of various cervical disc prostheses. STUDY DESIGN/SETTING Analysis of 24-month postoperative FE-ROM data from clinical trials. PATIENT SAMPLE Data from 1,173 patients from single-level disc replacement clinical trials of 7 cervical disc prostheses. OUTCOME MEASURES 24-month postoperative index-level FE-ROM. METHODS The FE-ROM histograms reported in Food and Drug Administration-Investigational Device Exemption (FDA-IDE) submissions and available for this analysis were used to calculate the frequencies of implanted levels with postoperative FE-ROM in the following motion-ranges: Hypomobile (0°-4°), Physiological (5°-16°), and Hypermobile (≥17°). The ROM histograms also allowed calculation of the average ROM of implanted segments in each of the 3 motion-ranges. RESULTS Only 762 of 1,173 patients (implanted levels) yielded 24-month postCDA FE-ROM in the physiological mobility range (5°-16°). The proportions ranged from 60% to 79% across the 7 disc-prostheses, with an average of 65.0%±6.2%. Three-hundred and two (302) of 1,173 implanted levels yielded ROM in the 0°-4° range. The proportions ranged from 15% to 38% with an average of 25.7%±8.9%. One-hundred and nine (109) of 1,173 implanted levels yielded ROM of ≥17° with a range of 2%-21% and an average proportion of 9.3%±7.9%. The prosthesis with built-in stiffness due to its nucleus-annulus design yielded the highest proportion (103/131, 79%) of implanted segments in the physiological mobility range, compared to the cohort average of 65% (p<.01). Sixty-five of the 350 (18.6%) discs implanted with the 2 mobile-core designs in this cohort yielded ROM≥17° as compared to the cohort average of 9.3% (109/1,173) (p<.05). At 2-year postCDA, the "hypomobile" segments moved on average 2.4±1.2°, those in the "physiological-mobility" group moved 9.4±3.2°, and the hypermobile segments moved 19.6±2.6°. CONCLUSIONS Prosthesis design significantly influenced the likelihood of achieving FE-ROM in the physiological mobility range, while avoiding hypomobility or hypermobility (p<.01). Postoperative ROM averaged over all study subjects provides incomplete information about the prosthesis performance - it does not tell us how many implanted segments achieve physiological mobility and how many end up with hypomobility or hypermobility. We conclude that the proportion of index levels achieving postCDA motions in the physiological mobility range (5°-16°) is a more useful outcome measure for future clinical trials.
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Affiliation(s)
- Avinash G Patwardhan
- Musculoskeletal Biomechanics Laboratory, Edward Hines Jr. VA Hospital, Hines, IL, USA; Department of Orthopaedic Surgery and Rehabilitation, Loyola University Chicago, Maywood, IL, USA.
| | - Robert M Havey
- Musculoskeletal Biomechanics Laboratory, Edward Hines Jr. VA Hospital, Hines, IL, USA
| | - Frank M Phillips
- Department of Orthopedic Surgery, Rush University Medical Center, Chicago, IL, USA
| | - Jack E Zigler
- Center for Disc Replacement, Texas Back Institute, Plano, TX, USA
| | | | - Richard Guyer
- Center for Disc Replacement, Texas Back Institute, Plano, TX, USA
| | - Todd Lanman
- Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Muturi G Muriuki
- Musculoskeletal Biomechanics Laboratory, Edward Hines Jr. VA Hospital, Hines, IL, USA
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Patel S, Schupper AJ, Ezzat B, Asfaw Z, Yuk FJ, Stein A, Choudhri TF. The Top 100 Cited Articles on Cervical Disc Arthroplasty: A Bibliometric Analysis. Clin Spine Surg 2024:01933606-990000000-00312. [PMID: 38679817 DOI: 10.1097/bsd.0000000000001636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 03/11/2024] [Indexed: 05/01/2024]
Abstract
STUDY DESIGN Bibliometric analysis. OBJECTIVE Cervical disc arthroplasty (CDA) has emerged as an effective surgical intervention for degenerative cervical disc disease with potential advantages over traditional cervical fusion. This bibliometric analysis aimed to assess the current state of research on CDA by analyzing the relevant literature using bibliometric indicators. SUMMARY OF BACKGROUND DATA Web of Science Core Collection. METHODS A comprehensive search was conducted using the Web of Science database, for articles related to CDA published in the last 19 years. The top 100 articles were reviewed using bibliometric analysis. Publication trends, citation patterns, authorship, and collaboration networks were analyzed using VOSviewer and the Bibliometrix package in RStudio. RESULTS The results revealed a significant increase in the number of publications related to CDA over the past 2 decades, with most of the articles being published in orthopedic and spine surgery journals. The most frequently cited articles were related to clinical outcomes, complications, and biomechanical studies of CDA. Co-authorship analysis identified influential authors and collaborative networks, highlighting the multidisciplinary nature of CDA research involving neurosurgeons, orthopedic surgeons, and engineers. Overall, this bibliometric analysis provides a comprehensive overview of the current state of research on CDA, highlighting the key research themes, influential authors, and collaborative networks in the field. CONCLUSION These findings can serve as a guide for researchers, clinicians, and policymakers to identify knowledge gaps, research trends, and future directions in the field of CDA.
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Affiliation(s)
- Shrey Patel
- Tufts University School of Medicine, Boston, MA
| | - Alexander J Schupper
- Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Bahie Ezzat
- Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Zerubabbel Asfaw
- Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Frank J Yuk
- Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Alan Stein
- Department of Neurosurgery, Westchester Medical Center, Valhalla, NY
| | - Tanvir F Choudhri
- Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, NY
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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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Vogt M, Zengerle L, Jonas R, Wilke HJ. The move-C cervical artificial disc can restore intact range of motion and 3-D kinematics. Spine J 2024; 24:340-351. [PMID: 37660895 DOI: 10.1016/j.spinee.2023.08.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 08/15/2023] [Accepted: 08/29/2023] [Indexed: 09/05/2023]
Abstract
BACKGROUND CONTEXT In contrast to cervical discectomy and fusion, total disc replacement (TDR) aims at preserving the motion at the treated vertebral level. Spinal motion is commonly evaluated with the range of motion (ROM). However, more qualitative information about cervical kinematics before and after TDR is still lacking. PURPOSE The aim of this in vitro study was to investigate the influence of cervical TDR on ROM, instantaneous centers of rotation (ICR) and three-dimensional helical axes. STUDY DESIGN An in vitro study with human spine specimens under pure moment loading was conducted to evaluate the kinematics of the intact cervical spine and compare it to cervical TDR. METHODS Six fresh frozen human cervical specimens (C4-5, median age 28 years, range 19-47 years, two female and four male) were biomechanically characterized in the intact state and after implantation of a cervical disc prosthesis (MOVE-C, NGMedical, Germany). To mimic in vivo conditions regarding temperature and humidity, water steam was used to create a warm and humid test environment with 37°C. Each specimen was quasistatically loaded with pure moments up to ±2.5 Nm in flexion/extension (FE), lateral bending (LB) and axial rotation (AR) in a universal spine tester for 3.5 cycles at 1 °/s. For each third cycle of motion the ROM was evaluated and an established method was used to determine the helical axis and COR and to project them into three planar X-rays. Statistical analysis was conducted using a Friedman-test and post hoc correction with Dunn-Bonferroni-tests (p<.05). RESULTS After TDR, total ROM was increased in FE from 19.1° to 20.1°, decreased in LB from 14.6° to 12.6° and decreased in AR from 17.7° to 15.5°. No statistical differences between the primary ROM in the intact condition and ROM after TDR were detected. Coupled rotation between LB and AR were also maintained. The position and orientation of the helical axes after cervical TDR was in good agreement with the results of the intact specimens in all three motion directions. The ICR in FE and AR before and after TDR closely matched, while in LB the ICR after TDR were more caudal. The intact in vitro kinematics we found also resembled in vivo results of healthy individuals. CONCLUSION The results of this in vitro study highlight the potential of artificial cervical disc implants to replicate the quantity as well as the quality of motion of the intact cervical spine. CLINICAL SIGNIFICANCE Physiological motion preservation was a driving factor in the development of cervical TDR. Our results demonstrate the potential of cervical TDR to replicate in vivo kinematics in all three motion directions.
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Affiliation(s)
- Morten Vogt
- Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre Ulm, University of Ulm, Ulm, Germany
| | - Laura Zengerle
- Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre Ulm, University of Ulm, Ulm, Germany
| | - René Jonas
- Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre Ulm, University of Ulm, Ulm, Germany
| | - Hans-Joachim Wilke
- Institute of Orthopaedic Research and Biomechanics, Trauma Research Centre Ulm, University of Ulm, Ulm, Germany.
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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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10
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Jacobs CAM, Doodkorte RJP, Kamali SA, Abdelgawad AM, Ghazanfari S, Jockenhoevel S, Arts JJC, Tryfonidou MA, Meij BP, Ito K. Biomechanical evaluation of a novel biomimetic artificial intervertebral disc in canine cervical cadaveric spines. JOR Spine 2023; 6:e1251. [PMID: 37361332 PMCID: PMC10285750 DOI: 10.1002/jsp2.1251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 01/16/2023] [Accepted: 01/29/2023] [Indexed: 06/28/2023] Open
Abstract
Background Context Cervical disc replacement (CDR) aims to restore motion of the treated level to reduce the risk of adjacent segment disease (ASD) compared with spinal fusion. However, first-generation articulating devices are unable to mimic the complex deformation kinematics of a natural disc. Thus, a biomimetic artificial intervertebral CDR (bioAID), containing a hydroxyethylmethacrylate (HEMA)-sodium methacrylate (NaMA) hydrogel core representing the nucleus pulposus, an ultra-high-molecular-weight-polyethylene fiber jacket as annulus fibrosus, and titanium endplates with pins for primary mechanical fixation, was developed. Purpose To assess the initial biomechanical effect of the bioAID on the kinematic behavior of the canine spine, an ex vivo biomechanical study in 6-degrees-of-freedom was performed. Study Design A canine cadaveric biomechanical study. Methods Six cadaveric canine specimens (C3-C6) were tested in flexion-extension (FE), lateral bending (LB) axial rotation (AR) using a spine tester in three conditions: intact, after C4-C5 disc replacement with bioAID, and after C4-C5 interbody fusion. A hybrid protocol was used where first the intact spines were subjected to a pure moment of ±1 Nm, whereafter the treated spines were subjected to the full range of motion (ROM) of the intact condition. 3D segmental motions at all levels were measured while recording the reaction torsion. Biomechanical parameters studied included ROM, neutral zone (NZ), and intradiscal pressure (IDP) at the adjacent cranial level (C3-C4). Results The bioAID retained the sigmoid shape of the moment-rotation curves with a NZ similar to the intact condition in LB and FE. Additionally, the normalized ROMs at the bioAID-treated level were statistically equivalent to intact during FE and AR while slightly decreased in LB. At the two adjacent levels, ROMs showed similar values for the intact compared to the bioAID for FE and AR and an increase in LB. In contrast, levels adjacent to the fused segment showed an increased motion in FE and LB as compensation for the loss of motion at the treated level. The IDP at the adjacent C3-C4 level after implantation of bioAID was close to intact values. After fusion, increased IDP was found compared with intact but did not reach statistical significance. Conclusion This study indicates that the bioAID can mimic the kinematic behavior of the replaced intervertebral disc and preserves that for the adjacent levels better than fusion. As a result, CDR using the novel bioAID is a promising alternative treatment for replacing severely degenerated intervertebral discs.
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Affiliation(s)
- Celien A. M. Jacobs
- Orthopedic Biomechanics, Department of Biomedical EngineeringEindhoven University of TechnologyEindhovenNoord‐BrabantThe Netherlands
| | - Remco J. P. Doodkorte
- Department of Orthopedic Surgery, Research School CAPHRIMaastricht University Medical CenterMaastrichtLimburgThe Netherlands
| | - S. Amir Kamali
- Department of Clinical Sciences, Faculty of Veterinary MedicineUtrecht UniversityUtrechtUtrechtThe Netherlands
| | - Abdelrahman M. Abdelgawad
- Aachen‐Maastricht Institute for Biobased Materials, Faculty of Science and EngineeringMaastricht UniversityGeleenLimburgThe Netherlands
| | - Samaneh Ghazanfari
- Aachen‐Maastricht Institute for Biobased Materials, Faculty of Science and EngineeringMaastricht UniversityGeleenLimburgThe Netherlands
| | - Stefan Jockenhoevel
- Aachen‐Maastricht Institute for Biobased Materials, Faculty of Science and EngineeringMaastricht UniversityGeleenLimburgThe Netherlands
- Department of Biohybrid and Medical Textiles (BioTex), AME – Institute of Applied Medical EngineeringHelmholtz Institute, RWTH Aachen UniversityAachenNordrhein‐WestfalenGermany
| | - J. J. Chris Arts
- Orthopedic Biomechanics, Department of Biomedical EngineeringEindhoven University of TechnologyEindhovenNoord‐BrabantThe Netherlands
- Department of Orthopedic Surgery, Research School CAPHRIMaastricht University Medical CenterMaastrichtLimburgThe Netherlands
| | - Marianna A. Tryfonidou
- Department of Clinical Sciences, Faculty of Veterinary MedicineUtrecht UniversityUtrechtUtrechtThe Netherlands
| | - Björn P. Meij
- Department of Clinical Sciences, Faculty of Veterinary MedicineUtrecht UniversityUtrechtUtrechtThe Netherlands
| | - Keita Ito
- Orthopedic Biomechanics, Department of Biomedical EngineeringEindhoven University of TechnologyEindhovenNoord‐BrabantThe Netherlands
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11
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Hsieh MK, Tai CL, Li YD, Lee DM, Lin CY, Tsai TT, Lai PL, Chen WP. Finite element analysis of optimized novel additively manufactured non-articulating prostheses for cervical total disc replacement. Front Bioeng Biotechnol 2023; 11:1182265. [PMID: 37324423 PMCID: PMC10267663 DOI: 10.3389/fbioe.2023.1182265] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 05/22/2023] [Indexed: 06/17/2023] Open
Abstract
Ball-and-socket designs of cervical total disc replacement (TDR) have been popular in recent years despite the disadvantages of polyethylene wear, heterotrophic ossification, increased facet contact force, and implant subsidence. In this study, a non-articulating, additively manufactured hybrid TDR with an ultra-high molecular weight polyethylene core and polycarbonate urethane (PCU) fiber jacket, was designed to mimic the motion of normal discs. A finite element (FE) study was conducted to optimize the lattice structure and assess the biomechanical performance of this new generation TDR with an intact disc and a commercial ball-and-socket Baguera®C TDR (Spineart SA, Geneva, Switzerland) on an intact C5-6 cervical spinal model. The lattice structure of the PCU fiber was constructed using the Tesseract or the Cross structures from the IntraLattice model in the Rhino software (McNeel North America, Seattle, WA) to create the hybrid I and hybrid II groups, respectively. The circumferential area of the PCU fiber was divided into three regions (anterior, lateral and posterior), and the cellular structures were adjusted. Optimal cellular distributions and structures were A2L5P2 in the hybrid I and A2L7P3 in the hybrid II groups. All but one of the maximum von Mises stresses were within the yield strength of the PCU material. The range of motions, facet joint stress, C6 vertebral superior endplate stress and path of instantaneous center of rotation of the hybrid I and II groups were closer to those of the intact group than those of the Baguera®C group under 100 N follower load and pure moment of 1.5 Nm in four different planar motions. Restoration of normal cervical spinal kinematics and prevention of implant subsidence could be observed from the FE analysis results. Superior stress distribution in the PCU fiber and core in the hybrid II group revealed that the Cross lattice structure of a PCU fiber jacket could be a choice for a next-generation TDR. This promising outcome suggests the feasibility of implanting an additively manufactured multi-material artificial disc that allows for better physiological motion than the current ball-and-socket design.
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Affiliation(s)
- Ming-Kai Hsieh
- Department of Orthopaedic Surgery, Spine Section, Bone and Joint Research Center, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Ching-Lung Tai
- Department of Orthopaedic Surgery, Spine Section, Bone and Joint Research Center, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan
- Department of Biomedical Engineering, Chang Gung University, Taoyuan, Taiwan
| | - Yun-Da Li
- Department of Orthopaedic Surgery, Spine Section, Bone and Joint Research Center, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan
- Department of Biomedical Engineering, Chang Gung University, Taoyuan, Taiwan
| | - De-Mei Lee
- Department of Mechanical Engineering, Chang Gung University, Taoyuan, Taiwan
| | - Cheng-Yi Lin
- Department of Mechanical Engineering, National Taipei University of Technology, Taipei, Taiwan
| | - Tsung-Ting Tsai
- Department of Orthopaedic Surgery, Spine Section, Bone and Joint Research Center, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Po-Liang Lai
- Department of Orthopaedic Surgery, Spine Section, Bone and Joint Research Center, Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Taoyuan, Taiwan
| | - Weng-Pin Chen
- Department of Mechanical Engineering, National Taipei University of Technology, Taipei, Taiwan
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12
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Clohisy JCF, Abjornson C, Bauer TW, Baral E, Albert TJ. Delayed Failure of M6-C Cervical Disc Arthroplasty After Conversion of Adjacent Cervical Disc Arthroplasty to Fusion: A Case Report. JBJS Case Connect 2023; 13:01709767-202306000-00013. [PMID: 37071739 DOI: 10.2106/jbjs.cc.22.00788] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
CASE We present a delayed failure of an M6-C cervical disc arthroplasty after conversion of a subjacent failed cervical disc arthroplasty to fusion. The annular component had failed, and the core had been ejected. Histology demonstrated a giant cell reaction to polyethylene debris, and tissue cultures were positive for Cutibacterium acnes. CONCLUSION This is the first report of M6-C failure after conversion of an adjacent arthroplasty to fusion. A growing number of reports surrounding the M6-C failure rate and mechanisms raise concern about the device's durability and underscore the importance of routine clinical and radiographic surveillance for these patients.
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Affiliation(s)
- John C F Clohisy
- Department of Orthopaedics, Hospital for Special Surgery, New York, New York
| | - Celeste Abjornson
- Integrated Spine Research Program, Hospital for Special Surgery, New York, New York
| | - Thomas W Bauer
- Department of Pathology and Laboratory Medicine, Hospital for Special Surgery, New York, New York
| | - Elexis Baral
- Department of Biomechanics, Hospital for Special Surgery, New York, New York
| | - Todd J Albert
- Department of Orthopaedics, Hospital for Special Surgery, New York, New York
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13
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Yu Z, Thakolkaran P, Shea K, Stanković T. Artificial neural network supported design of a lattice-based artificial spinal disc for restoring patient-specific anisotropic behaviors. Comput Biol Med 2022. [DOI: 10.1016/j.compbiomed.2022.106475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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14
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Kiapour A, Khandha A, Massaad E, Connolly ID, Hadzipasic M, Shankar GM, Goel V, Shin JH. Effects of rod diameter on kinematics of posterior cervical spine instrumented constructs: an ex vivo study. J Neurosurg Spine 2022; 37:749-757. [PMID: 35901764 DOI: 10.3171/2022.4.spine22202] [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: 02/13/2022] [Accepted: 04/07/2022] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Posterior cervical spine fixation is a robust strategy for stabilizing the spine for a wide range of spinal disorders. With the evolution of spinal implant technology, posterior fixation with lateral mass screws in the subaxial spine is now common. Despite interest in variable rod diameters to meet a wide range of clinical needs such as trauma, revision, and deformity surgery, indications for use of posterior cervical spine fixation are not clear. This laboratory investigation evaluates the mechanical stability and kinematic properties of lateral mass fixation with various commercially available rod diameters. METHODS The authors conducted an ex vivo experiment using 13 fresh-frozen human cervical spine specimens, instrumented from C3 to C6 with lateral mass screws, to evaluate the effects of titanium rod diameter on kinematic stability. Each intact spine was tested using a kinematic profiling machine with an optoelectrical camera and infrared sensors applying 1.5-Nm bending moments to the cranial vertebra (C2) simulating flexion-extension, lateral bending, and axial rotation anatomical motions. A compressive follower preload of 150 N was applied in flexion-extension prior to application of a bending moment. Instrumented spines were then tested with rod diameters of 3.5, 4.0, and 4.5 mm. The kinematic data between intact and surgical cases were studied using a nonparametric Wilcoxon signed-rank test. A multivariable, multilevel linear regression model was built to identify the relationship between segmental motion and rod diameter. RESULTS Instrumentation resulted in significant reduction in range of motion in all three rod constructs versus intact specimens in flexion-extension, lateral bending, and axial rotation (p < 0.05). The maximum reductions in segmental ROM versus intact spines in 3.5-, 4.0-, and 4.5-mm rod constructs were 61%, 71%, and 81% in flexion-extension; 70%, 76%, and 81% in lateral bending; and 50%, 60%, and 75% in axial rotation, respectively. Segmental motion at the adjacent segments (C2-3 and C6-7) increased significantly (p < 0.05) with increasing rod diameter. The 4.5-mm rod construct had the greatest increase in motion compared to the intact spine. CONCLUSIONS With increasing rod diameters from 3.5 to 4.0 mm, flexion-extension, lateral bending, and axial rotation across C3-6 were significantly reduced (p < 0.05). Similar trends were observed with a statistically significant reduction in motion in all anatomical planes when the rod diameter was increased to 4.5 mm. Although the increase in rod diameter resulted in a more rigid construct, it also created an increase (p < 0.05) in the kinematics of the adjacent segments (C2-3 and C6-7). Whether this increase translates into adverse long-term clinical effects in vivo requires further investigation and clinical assessment.
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Affiliation(s)
- Ali Kiapour
- 1Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Ashutosh Khandha
- 2Department of Biomedical Engineering, University of Delaware, Newark, Delaware; and
| | - Elie Massaad
- 1Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Ian D Connolly
- 1Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Muhamed Hadzipasic
- 1Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Ganesh M Shankar
- 1Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Vijay Goel
- 3Engineering Center for Orthopaedic Research Excellence (E-CORE), Department of Bioengineering Engineering, The University of Toledo, Ohio
| | - John H Shin
- 1Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
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15
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Colman MW, Zavras AG, Federico VP, Nolte MT, Butler AJ, Singh K, Phillips FM. Longitudinal assessment of segmental motion of the cervical spine following total disc arthroplasty: a comparative analysis of devices. J Neurosurg Spine 2022; 37:556-562. [PMID: 35426820 DOI: 10.3171/2022.2.spine22143] [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: 01/31/2022] [Accepted: 02/28/2022] [Indexed: 11/06/2022]
Abstract
OBJECTIVE Total disc arthroplasty (TDA) has been shown to be an effective and safe treatment for cervical degenerative disc disease at short- and midterm follow-up. However, there remains a paucity of literature reporting the differences between individual prosthesis designs with regard to device performance. In this study, the authors evaluated the long-term maintenance of segmental range of motion (ROM) at the operative cervical level across a diverse range of TDA devices. METHODS In this study, the authors retrospectively evaluated all consecutive patients who underwent 1- or 2-level cervical TDA between 2005 and 2020 at a single institution. Patients with a minimum of 6 months of follow-up and lateral flexion/extension radiographs preoperatively, 2 months postoperatively, and at final follow-up were included. Radiographic measurements included static segmental lordosis, segmental range of motion (ROM) on flexion/extension, global cervical (C2-7) ROM on flexion/extension, and disc space height. The paired t-test was used to evaluate improvement in radiographic parameters. Subanalysis between devices was performed using one-way ANCOVA. Significance was determined at p < 0.05. RESULTS A total of 85 patients (100 discs) were included, with a mean patient age of 46.01 ± 8.82 years and follow-up of 43.56 ± 39.36 months. Implantations included 22 (22.00%) M6-C, 51 (51.00%) Mobi-C, 14 (14.00%) PCM, and 13 (13.00%) ProDisc-C devices. There were no differences in baseline radiographic parameters between groups. At 2 months postoperatively, PCM provided significantly less segmental lordosis (p = 0.037) and segmental ROM (p = 0.039). At final follow-up, segmental ROM with both the PCM and ProDisc-C devices was significantly less than that with the M6-C and Mobi-C devices (p = 0.015). From preoperatively to 2 months postoperatively, PCM implantation led to a significant loss of lordosis (p < 0.001) and segmental ROM (p = 0.005) relative to the other devices. Moreover, a significantly greater decline in segmental ROM from 2 months postoperatively to final follow-up was seen with ProDisc-C, while segmental ROM increased significantly over time with Mobi-C (p = 0.049). CONCLUSIONS Analysis by TDA device brand demonstrated that motion preservation differs depending on disc design. Certain devices, including M6-C and Mobi-C, improve ROM on flexion/extension from preoperatively to postoperatively and continue to increase slightly at final follow-up. On the other hand, devices such as PCM and ProDisc-C contributed to greater segmental stiffness, with a gradual decline in ROM seen with ProDisc-C. Further studies are needed to understand how much segmental ROM is ideal after TDA for preservation of physiological cervical kinematics.
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16
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Yan C, Wang H, Wu T, Huang C, Abuduaini H, Wang B, Liu H. Effect of facet joint distraction on the functional and radiological outcomes after anterior cervical disc replacement. BMC Musculoskelet Disord 2022; 23:741. [PMID: 35922787 PMCID: PMC9347160 DOI: 10.1186/s12891-022-05705-y] [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: 03/16/2022] [Accepted: 07/26/2022] [Indexed: 02/08/2023] Open
Abstract
OBJECTIVE The purpose of this study is to explore: 1) whether the extent of facet joint distraction affects functional outcomes following single-level anterior cervical disc replacement (ACDR) for cervical spondylotic radiculopathy and 2) whether the extent of facet joint distraction correlates with the cervical sagittal parameters. METHODS We performed a retrospective analysis on 70 patients who had undergone a single-level ACDR to treat cervical spondylotic radiculopathy between January 2014 and December 2018. Pre- and post-operative lateral cervical spine X-ray radiographs were collected to determine radiographic parameters, including C0-C2 angle, C2-C7 angle, C7 Slope (C7S), T1 Slope (T1S), C2-C7 sagittal vertical axis (SVA), C2-C7 range of motion (ROM), Segmental ROM, disc height (DH) and inter-facet distance (ID). And the extend of facet joint distraction was evaluated by the two indexes: degree of intervertebral distraction (DID) defined and degree of facet joint distraction (DFJD). The visual analog scale (VASneck) and the Neck Disability Index scores (NDI) were adopted to demonstrate functional outcomes. Patients with the functional outcome improvement below the average were set as the positive group in the receiver operating characteristic (ROC) curve analysis, to find an optimal cut-off value of extent of facet joint distraction. RESULTS VASneck and NDI scores improved significantly from pre- to post-operation among the entire cohort, and DFJD had a statistically significant negative correlation with ΔVASneck (p < 0.001) and ΔNDI (p < 0.001). According to ROC curve analysis, the cut-off value of DFJD for differing the appropriate and excessive distraction groups was set at 29.16% (sensitivity = 70.73%, specificity = 67.86%). Between these two groups, the ΔT1S, ΔROM, ΔVASneck, and ΔNDI were significantly different (p < 0.05). CONCLUSION Single-segment ACDR may improve the functional outcome of patients with cervical spondylotic radiculopathy. However, those whose DFJD was greater than 29.16% had worse VASneck and NDI scores, as well as a lower ΔT1S and a lower ΔROM.
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Affiliation(s)
- Chunyi Yan
- Department of Orthopedics, West China Hospital, Sichuan University, #37 Guoxue Alley, Wuhou District, Chengdu, Sichuan Province, People's Republic of China
| | - Hong Wang
- Department of Orthopedics, West China Hospital, Sichuan University, #37 Guoxue Alley, Wuhou District, Chengdu, Sichuan Province, People's Republic of China
| | - Tingkui Wu
- Department of Orthopedics, West China Hospital, Sichuan University, #37 Guoxue Alley, Wuhou District, Chengdu, Sichuan Province, People's Republic of China
| | - Chengyi Huang
- Department of Orthopedics, West China Hospital, Sichuan University, #37 Guoxue Alley, Wuhou District, Chengdu, Sichuan Province, People's Republic of China
| | - Haimiti Abuduaini
- Department of Orthopedics, West China Hospital, Sichuan University, #37 Guoxue Alley, Wuhou District, Chengdu, Sichuan Province, People's Republic of China
| | - Beiyu Wang
- Department of Orthopedics, West China Hospital, Sichuan University, #37 Guoxue Alley, Wuhou District, Chengdu, Sichuan Province, People's Republic of China
| | - Hao Liu
- Department of Orthopedics, West China Hospital, Sichuan University, #37 Guoxue Alley, Wuhou District, Chengdu, Sichuan Province, People's Republic of China.
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17
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Wellington IJ, Kia C, Coskun E, Torre BB, Antonacci CL, Mancini MR, Connors JP, Esmende SM, Makanji HS. Cervical and Lumbar Disc Arthroplasty: A Review of Current Implant Design and Outcomes. Bioengineering (Basel) 2022; 9:bioengineering9050227. [PMID: 35621505 PMCID: PMC9137579 DOI: 10.3390/bioengineering9050227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 05/16/2022] [Accepted: 05/18/2022] [Indexed: 11/16/2022] Open
Abstract
While spinal disc pathology has traditionally been treated using fusion-based procedures, recent interest in motion-preserving disc arthroplasties has grown. Traditional spinal fusion is associated with loss of motion, alteration of native spine kinematics, and increased risks of adjacent segment disease. The motion conferred by disc arthroplasty is believed to combat these complications. While the first implant designs resulted in poor patient outcomes, recent advances in implant design and technology have shown promising radiographic and clinical outcomes when compared with traditional fusion. These results have led to a rapid increase in the utilization of disc arthroplasty, with rates of cervical arthroplasty nearly tripling over the course of 7 years. The purpose of this review was to discuss the evolution of implant design, the current implant designs utilized, and their associated outcomes. Although disc arthroplasty shows significant promise in addressing some of the drawbacks associated with fusion, it is not without its own risks. Osteolysis, implant migration, and the development of heterotopic ossification have all been associated with disc arthroplasty. As interest in these procedures grows, so does the interest in developing improved implant designs aimed at decreasing these adverse outcomes. Though they are still relatively new, cervical and lumbar disc arthroplasty are likely to become foundational methodologies for the treatment of disc pathology.
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Affiliation(s)
- Ian J. Wellington
- Department of Orthopaedics, University of Connecticut, Farmington, CT 06032, USA; (I.J.W.); (E.C.); (B.B.T.); (C.L.A.); (M.R.M.); (J.P.C.)
| | - Cameron Kia
- Department of Orthopaedics, University of Connecticut, Farmington, CT 06032, USA; (I.J.W.); (E.C.); (B.B.T.); (C.L.A.); (M.R.M.); (J.P.C.)
- Correspondence:
| | - Ergin Coskun
- Department of Orthopaedics, University of Connecticut, Farmington, CT 06032, USA; (I.J.W.); (E.C.); (B.B.T.); (C.L.A.); (M.R.M.); (J.P.C.)
| | - Barrett B. Torre
- Department of Orthopaedics, University of Connecticut, Farmington, CT 06032, USA; (I.J.W.); (E.C.); (B.B.T.); (C.L.A.); (M.R.M.); (J.P.C.)
| | - Christopher L. Antonacci
- Department of Orthopaedics, University of Connecticut, Farmington, CT 06032, USA; (I.J.W.); (E.C.); (B.B.T.); (C.L.A.); (M.R.M.); (J.P.C.)
| | - Michael R. Mancini
- Department of Orthopaedics, University of Connecticut, Farmington, CT 06032, USA; (I.J.W.); (E.C.); (B.B.T.); (C.L.A.); (M.R.M.); (J.P.C.)
| | - John P. Connors
- Department of Orthopaedics, University of Connecticut, Farmington, CT 06032, USA; (I.J.W.); (E.C.); (B.B.T.); (C.L.A.); (M.R.M.); (J.P.C.)
| | - Sean M. Esmende
- Department of Orthopedics, Hartford Healthcare, Hartford, CT 06106, USA; (S.M.E.); (H.S.M.)
| | - Heeren S. Makanji
- Department of Orthopedics, Hartford Healthcare, Hartford, CT 06106, USA; (S.M.E.); (H.S.M.)
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18
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Midterm osteolysis-induced aseptic failure of the M6-C™ cervical total disc replacement secondary to polyethylene wear debris. 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 2022; 31:1273-1282. [PMID: 35020078 DOI: 10.1007/s00586-021-07094-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 12/18/2021] [Indexed: 10/19/2022]
Abstract
BACKGROUND According to published meta-analyses, cervical total disc replacement (CTDR) seems to be superior to anterior cervical decompression and fusion (ACDF) in most clinical parameters. Despite short-term clinical success of CTDR, there are concerns regarding long-term durability of these prostheses. METHODS This prospective study involved 382 patients who received standalone CTDR or a hybrid procedure (ACDF/CTDR). A retrospective comparison between different CTDR devices was conducted regarding patient-reported outcome measures (PROMs), failure scenarios, and revision surgeries. The M6-C™ Artificial Cervical Disc (Orthofix, Lewisville, Texas) cohort was compared to the other CTDR devices clinically. Etiological reasons for revision, and the surgical technique of the revision was investigated. RESULTS Fifty-three patients received M6-C CTDR. Eighteen patients (34%) were revised at an average of 67 months postoperatively for wear-induced osteolysis. There were three additional cases of pending revision. The PROMs of the two groups were similar, indicating that the failure mode (wear-induced osteolysis) is often asymptomatic. The demographics of the two groups were also similar, with more women undergoing revision surgery than men. There were three one-level CTDR, four two-level hybrids, seven three-level hybrids, and three four-level hybrids revised anteriorly. Sixteen patients underwent removal of the prosthesis and were treated according to the extent of osteolysis. There were four vertebrectomies, six revisions to ACDF, and six revisions to another CTDR. One patient underwent supplemental fixation using a posterior approach. The other CTDR cohort had an incidence of 3.3% at the equivalent time, and none of these were due to osteolysis or wear-related events. CONCLUSIONS There is a concerning midterm failure rate related to ultra-high-molecular-weight-polyethylene wear-induced osteolysis in the M6-C. Patients implanted with the M6-C prosthesis should be contacted, informed, and clinically and radiologically assessed.
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Shin JJ, Kim KR, Son DW, Shin DA, Yi S, Kim KN, Yoon DH, Ha Y. Radiological Changes in Adjacent and Index Levels after Cervical Disc Arthroplasty. Yonsei Med J 2022; 63:72-81. [PMID: 34913286 PMCID: PMC8688375 DOI: 10.3349/ymj.2022.63.1.72] [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] [Received: 04/07/2021] [Revised: 07/08/2021] [Accepted: 07/19/2021] [Indexed: 11/27/2022] Open
Abstract
PURPOSE The purpose of this retrospective study was to evaluate radiological and clinical outcomes in patients undergoing cervical disc arthroplasty (CDA) for cervical degenerative disc disease. The results may assist in surgical decision-making and enable more effective and safer implementation of cervical arthroplasty. MATERIALS AND METHODS A total of 125 patients who were treated with CDA between 2006 and 2019 were assessed. Radiological measurements and clinical outcomes included the visual analogue scale (VAS), the Neck Disability Index (NDI), and the Japanese Orthopaedic Association (JOA) myelopathy score assessment preoperatively and at ≥2 years of follow-up. RESULTS The mean follow-up period was 38 months (range, 25-114 months). Radiographic data demonstrated mobility at both the index and adjacent levels, with no signs of hypermobility at an adjacent level. There was a non-significant loss of cervical global motion and range of motion (ROM) of the functional spinal unit at the operated level, as well as the upper and lower adjacent disc levels, compared to preoperative status. The cervical global and segmental angle significantly increased. Postoperative neck VAS, NDI, and JOA scores showed meaningful improvements after one- and two-level CDA. We experienced a 29.60% incidence of heterotrophic ossification and a 3.20% reoperation rate due to cervical instability, implant subsidence, or osteolysis. CONCLUSION CDA is an effective surgical technique for optimizing clinical outcomes and radiological results. In particular, the preservation of cervical ROM with an artificial prosthesis at adjacent and index levels and improvement in cervical global alignment could reduce revision rates due to adjacent segment degeneration.
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Affiliation(s)
- Jun Jae Shin
- Department of Neurosurgery, Yongin Severance Hospital, Yonsei University School of Medicine, Yongin, Korea
| | - Kwang-Ryeol Kim
- Department of Neurosurgery, International St. Mary's Hospital, Catholic Kwandong University College of Medicine, Incheon, Korea
| | - Dong Wuk Son
- Department of Neurosurgery, Pusan National University Yangsan Hospital, School of Medicine, Pusan National University, Yangsan, Korea
| | - Dong Ah Shin
- Department of Neurosurgery, Spine and Spinal Cord Institute, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Seong Yi
- Department of Neurosurgery, Spine and Spinal Cord Institute, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Keung-Nyun Kim
- Department of Neurosurgery, Spine and Spinal Cord Institute, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Do-Heum Yoon
- Department of Neurosurgery, Spine and Spinal Cord Institute, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Yoon Ha
- Department of Neurosurgery, Spine and Spinal Cord Institute, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
- POSTECH Biotech Center, Pohang University of Science and Technology, Pohang, Korea.
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20
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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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21
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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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22
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Alves ÓL. Cervical Total Disc Replacement: Expanded Indications. Neurosurg Clin N Am 2021; 32:437-448. [PMID: 34538470 DOI: 10.1016/j.nec.2021.05.002] [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: 11/16/2022]
Abstract
Cervical total disc replacement (cTDR) is now a firm alternative to anterior cervical discectomy and fusion (ACDF) for degenerative disc disease (DDD). Robust level 1 data from Federal Drug Administration-approved clinical trials demonstrated that cTDR is in any case equally safe and effective compared with ACDF for 1- or 2-level DDD. Furthermore, from early postoperative to long-term follow-up of 10 to 15 years, cTDR rates superiorly in many primary clinical outcomes. According to the published literature, at least nine different cTDR devices share this consistent pattern. On the other hand, the surgical treatment of more than 2-level disc disease is haunted by an elusive paradox. It is easily understandable that 3- and 4-level ACDF, with the well-known associated limitations, is not the superlative intervention for a spine segment anatomically designed to provide motion, as cervical spine is. Furthermore, multilevel ACDF exacerbates many of the clinical and biomechanical complications related with single-level fusion. However, as cTDR is not immaculate of constraints and failures, its clinical safety and efficacy and cost-effectiveness in multilevel anterior compressive pathology need to be established. This article analyses the current available evidence supporting the expanded indication of cTDR to 3- and 4-level disc disease, either stand-alone or adjacent to fusion, from a less stringent European perspective.
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Affiliation(s)
- Óscar L Alves
- Hospital Lusíadas Porto; Centro Hospitalar de Gaia/Espinho, Rua Cónego Ferreira Pinto, 191, 4050-256 Porto, Portugal.
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23
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Shin JJ, Kim KR, Son DW, Shin DA, Yi S, Kim KN, Yoon DH, Ha Y, Riew KD. Cervical disc arthroplasty: What we know in 2020 and a literature review. J Orthop Surg (Hong Kong) 2021; 29:23094990211006934. [PMID: 34581615 DOI: 10.1177/23094990211006934] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Cervical disc arthroplasty (CDA) is a safe and effective option to improve clinical outcomes (e.g., NDI, VAS, and JOA) in degenerative cervical disc disease and compressive myelopathy. CDA's two main purported benefits have been that it maintains physiologic motion and thereby minimizes the biomechanical stresses placed on adjacent segments as compared to an ACDF. CDA might reduce the degeneration of adjacent segments, and the need for adjacent-level surgery. Reoperation rates of CDA have been reported to range from 1.8% to 5.4%, with a minimum 5-year follow-up. As the number of CDA procedures performed continues to increase, the need for revision surgery is also likely to increase. When performed skillfully in appropriate patients, CDA is an effective surgical technique to optimize clinical outcomes and radiological results. This review may assist surgical decision-making and enable a more effective and safer implementation of cervical arthroplasty for cervical degenerative disease.
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Affiliation(s)
- Jun Jae Shin
- Department of Neurosurgery, Yongin Severance Hospital, 37991Yonsei University School of Medicine, Yongin, Korea
| | - Kwang-Ryeol Kim
- Department of Neurosurgery, International St Mary's Hospital, 54671Catholic Kwandong University, College of Medicine, Incheon, Korea
| | - Dong Wuk Son
- Department of Neurosurgery, 194197Pusan National University Yangsan Hospital, School of Medicine, Yangsan, Korea
| | - Dong Ah Shin
- Department of Neurosurgery, Spine and Spinal Cord Institute, Severance Hospital, 37991Yonsei University College of Medicine, Seoul, Korea
| | - Seong Yi
- Department of Neurosurgery, Spine and Spinal Cord Institute, Severance Hospital, 37991Yonsei University College of Medicine, Seoul, Korea
| | - Keung-Nyun Kim
- Department of Neurosurgery, Spine and Spinal Cord Institute, Severance Hospital, 37991Yonsei University College of Medicine, Seoul, Korea
| | - Do-Heum Yoon
- Department of Neurosurgery, Spine and Spinal Cord Institute, Severance Hospital, 37991Yonsei University College of Medicine, Seoul, Korea
| | - Yoon Ha
- Department of Neurosurgery, Spine and Spinal Cord Institute, Severance Hospital, 37991Yonsei University College of Medicine, Seoul, Korea.,POSTECH Biotech Center, Pohang University of Science and Technology, Pohang, Gyeongbuk, Korea
| | - K Daniel Riew
- Department of Orthopedic Surgery, 5798Columbia University College of Physicians and Surgeons, New York, NY, USA.,Department of Neurological Surgery, Weill Cornell Medical College, Cornell University, New York, NY, USA
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Schroeder GD, Vaccaro AR, Divi SN, Reyes AA, Goyal DKC, Phillips FM, Zigler J. 2021 Position Statement From the International Society for the Advancement of Spine Surgery on Cervical and Lumbar Disc Replacement. Int J Spine Surg 2021; 15:37-46. [PMID: 33900955 DOI: 10.14444/8004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Affiliation(s)
- Gregory D Schroeder
- Rothman Institute at Thomas Jefferson University Hospital, Philadelphia, Pennsylvania
| | - Alexander R Vaccaro
- Rothman Institute at Thomas Jefferson University Hospital, Philadelphia, Pennsylvania
| | | | - Ariana A Reyes
- Rothman Institute at Thomas Jefferson University Hospital, Philadelphia, Pennsylvania
| | - Dhruv K C Goyal
- Rothman Institute at Thomas Jefferson University Hospital, Philadelphia, Pennsylvania
| | - Frank M Phillips
- Midwest Orthopaedics at Rush, Rush University Medical Center, Chicago, Illinois
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Phillips FM, Coric D, Sasso R, Lanman T, Lavelle W, Blumenthal S, Lauryssen C, Guyer R, Albert T, Zigler J, Cammisa F, Milam RA. Prospective, multicenter clinical trial comparing M6-C compressible six degrees of freedom cervical disc with anterior cervical discectomy and fusion for the treatment of single-level degenerative cervical radiculopathy: 2-year results of an FDA investigational device exemption study. Spine J 2021; 21:239-252. [PMID: 33096243 DOI: 10.1016/j.spinee.2020.10.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 09/28/2020] [Accepted: 10/13/2020] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT Various designs of total disc replacement (TDR) devices have been compared to anterior cervical discectomy and fusion (ACDF) with favorable outcomes in FDA-approved investigational device exemption trials. The design of M6-C with a compressible viscoelastic nuclear core and an annular structure is substantially different than prior designs and has previously demonstrated favorable kinematics and clinical outcomes in small case series. PURPOSE To evaluate the safety and effectiveness of the novel M6-C compressible artificial cervical disc compared with ACDF for subjects with single-level degenerative cervical radiculopathy. STUDY DESIGN/SETTING Prospective, multicenter, concurrently and historically controlled, FDA-approved investigational device exemption clinical trial. PATIENT SAMPLE Subjects with one-level symptomatic degenerative cervical radiculopathy were enrolled and assigned to receive M6-C or ACDF. OUTCOME MEASURES Pain and function (Neck Disability Index, VAS), quality of life (SF-36), safety, neurologic, and radiographic assessments of motion (both flexion extension and lateral bending) were performed. The primary clinical endpoint was composite clinical success (CCS) at 24 months. METHODS Using propensity score subclassification to control for selection bias, 160 M6-C subjects were compared to a matched subset of 189 ACDF controls (46 concurrent and 143 historical controls). RESULTS Both ACDF and M6-C subjects reported significant improvements in patient-reported outcomes at all time points over baseline. Overall SF-36 Physical Component Score and neck and arm pain scores were significantly improved for M6-C as compared to ACDF treatment. CCS and mean Neck Disability Index improvements were similar between M6-C and ACDF. Correspondingly, there were significantly fewer subjects that utilized pain medication or opioids following M6-C treatment at 24 months relative to baseline. Range of motion was maintained in subjects treated with M6-C. Subsequent surgical interventions, dysphagia rates, and serious adverse events were comparable between groups. CONCLUSIONS M6-C treatment demonstrated both safety and effectiveness for the treatment of degenerative cervical radiculopathy. Treatment with M6-C demonstrated noninferiority for the primary endpoint, indicating a similar ability to achieve CCS at 24 months. However, for the secondary endpoints, M6-C subjects demonstrated significantly improved pain and function compared to ACDF subjects, while maintaining range of motion, improving quality of life, and decreasing analgesic and opioid usage at 2 years postoperatively relative to baseline.
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Affiliation(s)
- Frank M Phillips
- Midwest Orthopaedics at Rush University Medical Center, 1611 W Harrison St # 300, Chicago, IL 60612, USA.
| | - Domagoj Coric
- Carolina Neurosurgery & Spine Associates, Atruim Health Musculoskeletal Institute, 225 Baldwin Ave, Charlotte, NC 28204, USA
| | - Rick Sasso
- Indiana Spine Group, 13225 N Meridian St, Carmel, IN 46032, USA
| | - Todd Lanman
- Lanman Spinal Neurosurgery, 450 N Roxbury Dr, Beverly Hills, CA 90210, USA
| | - William Lavelle
- Upstate Bone and Joint Center, 6620 Fly Rd, East Syracuse, NY 13057, USA
| | - Scott Blumenthal
- Center for Disc Replacement at TBI, 6020 West Parker Rd #200, Plano, TX 75093, USA
| | - Carl Lauryssen
- Central Texas Brain and Spine, PLLC, 2217 Park Bend Dr, Unit 400, Austin TX 78758, USA
| | - Richard Guyer
- Center for Disc Replacement at TBI, 6020 West Parker Rd #200, Plano, TX 75093, USA
| | - Todd Albert
- Hospital for Special Surgery, 535 East 70th St, New York, NY 10021, USA
| | - Jack Zigler
- Center for Disc Replacement at TBI, 6020 West Parker Rd #200, Plano, TX 75093, USA
| | - Frank Cammisa
- Hospital for Special Surgery, 535 East 70th St, New York, NY 10021, USA
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26
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Jacobs CAM, Siepe CJ, Ito K. Viscoelastic cervical total disc replacement devices: Design concepts. Spine J 2020; 20:1911-1924. [PMID: 32810609 DOI: 10.1016/j.spinee.2020.08.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 08/12/2020] [Accepted: 08/12/2020] [Indexed: 02/03/2023]
Abstract
Cervical disc replacement (CDR) is a motion-preserving surgical procedure for treating patients with degenerative disorders. Numerous reports of first generation CDR "ball-and-socket" articulating devices have shown satisfactory clinical results. As a result, CDR devices have been safely implemented in the surgeon's armamentarium on a global scale. However, only minor design improvements have been made over the last few years, as first generation CDRs devices were based on traditional synovial joint arthroplasty designs. As a consequence, these articulating designs have limited resemblance to the complex kinematic behavior of a natural disc. This has driven the development of deformable viscoelastic CDR devices to better mimic the biomechanical behavior of a natural disc. As a result, several viscoelastic CDR devices have been developed in recent years that vary in terms of materials, design and clinical outcomes. Since these viscoelastic CDR devices are fairly new, their weaknesses and strengths, which are related to their design characteristics, have not been well described. Therefore, this literature review discusses design related advantages and disadvantages of deformable viscoelastic CDR devices. As such, this paper can provide insight for surgeons and engineers on specific design characteristics of several viscoelastic devices and could potentially help to develop and design future implants. Eleven viscoelastic CDR devices were identified. An extensive database search on the devices' tradenames in Medline and PubMed was performed next. The devices were categorized based on common design characteristics to give an overview of both category and device specific complications and advantages. Overall, literature shows that most of these viscoelastic CDR devices can provide motion in all six degrees-of-freedom and have a variable center of rotation. Nevertheless, the viscoelastic materials used do not have an extensive history in orthopedics, so the long-term material behavior in vivo is still unknown. Although the viscoelastic devices have common benefits and risks, each specific design and category also has its own design related advantages and drawbacks that are described in this review. Altogether, viscoelastic total disc replacements seem to be a promising option for the future of cervical arthroplasty, but long-term clinical outcome is needed to confirm the advantages of mimicking the viscoelasticity of a natural disc.
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Affiliation(s)
- Celien A M Jacobs
- Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, De Rondom 70, 5612 AP Eindhoven, the Netherlands.
| | - Christoph J Siepe
- Schoen Clinic Munich Harlaching, Spine Center, Harlachinger Str. 51, D-81547 Munich, Germany; Spine Research Institute and Academic Teaching Hospital of the Paracelsus University Salzburg (PMU), Strubergasse 21, A-5020 Salzburg, Austria
| | - Keita Ito
- Orthopaedic Biomechanics, Department of Biomedical Engineering, Eindhoven University of Technology, De Rondom 70, 5612 AP Eindhoven, the Netherlands
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27
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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: 20] [Impact Index Per Article: 5.0] [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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Lazennec JY. Lumbar and cervical viscoelastic disc replacement: Concepts and current experience. World J Orthop 2020; 11:345-356. [PMID: 32904082 PMCID: PMC7448204 DOI: 10.5312/wjo.v11.i8.345] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/23/2020] [Accepted: 07/19/2020] [Indexed: 02/06/2023] Open
Abstract
The ideal lumbar and cervical discs should provide six degrees of freedom and tri-planar (three-dimensional) motion. Although all artificial discs are intended to achieve the same goals, there is considerable heterogeneity in the design of lumbar and cervical implants. The “second generation total disc replacements” are non-articulating viscoelastic implants aiming at the reconstruction of physiologic levels of shock absorption and flexural stiffness. This review aims to give an overview of the available implants detailing the concepts and the functional results experimentally and clinically. These monobloc prostheses raise new challenges concerning the choice of materials for the constitution of the viscoelastic cushion, the connection between the components of the internal structure and the metal endplates and even the bone anchoring mode. New objectives concerning the quality of movement and mobility control must be defined.
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Affiliation(s)
- Jean Yves Lazennec
- Department of Orthopaedic and Trauma Surgery, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, Paris F-75013, France
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Sang H, Cui W, Sang D, Guo Z, Liu B. How Center of Rotation Changes and What Affects These After Cervical Arthroplasty: A Systematic Review and Meta-analysis. World Neurosurg 2020; 135:e702-e709. [DOI: 10.1016/j.wneu.2019.12.111] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 12/18/2019] [Indexed: 10/25/2022]
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30
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Hui N, Phan K, Kerferd J, Lee M, Mobbs RJ. Comparison of M6-C and Mobi-C cervical total disc replacement for cervical degenerative disc disease in adults. JOURNAL OF SPINE SURGERY 2019; 5:393-403. [PMID: 32042989 DOI: 10.21037/jss.2019.09.27] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Background Cervical total disc replacement (CTDR) is complicated by adjacent segment degeneration (ASD). Since non-physiological spine kinematics after CTDR was postulated to cause ASD, M6-C prosthesis has been developed to better replicate the natural kinematics of the intervertebral disc. This retrospective cohort study aims to compare the short-term outcomes between patients receiving either the M6-C or Mobi-C prostheses. Methods Patients who had refractory radiculopathy and/or myelopathy secondary to cervical degenerative disc disease and underwent CTDR between March 2004 and April 2017 were included. All CTDRs were performed by a single surgeon at a single institution. Self-reported clinical outcomes and radiological parameters were evaluated at baseline and final follow-up between March 2004 and April 2018. Results Sixty-two patients with greater than 1-year follow-up or who developed HO within 12 months of surgery, were included in the study. The mean radiological follow-up was 29.0 months (3-84 months), which includes 7 patients with less than 12 months follow-up who also developed HO. The changes in clinical and radiological measures were comparable between M6-C and Mobi-C prostheses. Thirty-seven out of 52 spinal segments (71.2%) and 10 out of 16 spinal segments (62.5%) developed HO in M6-C and Mobi-C group respectively. There was no significant difference in the rate of HO between the two groups. Conclusions No short-term differences were found in clinical or radiological outcomes between patients who received either the M6-C or Mobi-C prosthesis. Further randomized trials with a long-term follow-up period are warranted to determine the safety and efficacy of M6-C prosthesis.
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Affiliation(s)
- Nicholas Hui
- NeuroSpine Surgery Research Group (NSURG), The University of New South Wales, Sydney, NSW, Australia
| | - Kevin Phan
- NeuroSpine Surgery Research Group (NSURG), The University of New South Wales, Sydney, NSW, Australia
| | - Jack Kerferd
- NeuroSpine Surgery Research Group (NSURG), The University of New South Wales, Sydney, NSW, Australia
| | - Meiyi Lee
- NeuroSpine Surgery Research Group (NSURG), The University of New South Wales, Sydney, NSW, Australia
| | - Ralph J Mobbs
- NeuroSpine Surgery Research Group (NSURG), The University of New South Wales, Sydney, NSW, Australia
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31
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Oltulu İ, Korkmaz Ö, Sarıoğlu E, Aydoğan M. A Retrospective Review of Radiographic and Clinical Findings from the M6 Cervical Prosthesis. Asian Spine J 2019; 13:913-919. [PMID: 31422645 PMCID: PMC6894978 DOI: 10.31616/asj.2018.0346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/31/2018] [Accepted: 03/26/2019] [Indexed: 12/20/2022] Open
Abstract
Study Design Retrospective clinical study. Purpose To evaluate clinical results of the M6 cervical prosthesis. Overview of Literature Cervical disk prostheses have been developed to preserve motion and reduce degeneration in adjacent segments in degenerative disk diseases. Methods A retrospective evaluation was performed on 43 patients who received the M6 cervical disk prosthesis between 2012 and 2016. Standard and dynamic radiographs, computed tomography, and magnetic resonance imaging were used to evaluate all the patients preoperatively and postoperatively. The Neck Disability Index (NDI) and Visual Analog Scale (VAS) scores were examined in evaluating the clinical and functional results of patients with collapsed disk herniation who had received the M6 cervical prosthesis and to evaluate whether the core structure of the prosthesis protects motion. Results The mean follow-up period was 34.12±6.70 months. Radiologically, the preoperative cervical segment ROM was measured as a mean of 5.77°±2.19° preoperatively and 8.49°±2.37° at the inal postoperative follow-up examination. In the patients with a preoperative disk height of <4 mm, the segmental ROM increased from 4.53°±2.79° preoperatively to 7.2°±3.18° postoperatively. In the patients with a preoperative disk height of >4 mm, the cervical segment ROM increased from 6.4°±1.45° preoperatively to 8.6°±2.02° at the inal postoperative follow-up examination. The NDI scores reduced from 53.86±9.77 preoperatively to 22.69±7.26 postoperatively and the VAS scores reduced from 8.74±0.58 to 1.88±1.14. During follow-up in any patient, no collapse of the levels at which surgery was performed was observed. No heterotopic ossiication or implant failure was recorded in any patient during the follow-up period. Conclusions The M6 new-generation cervical disk prosthesis had few complications. No heterotopic ossiication was observed in any patient, and lexion-extension ROM was maintained in all the patients, indicating the M6 prosthesis as a promising alternative.
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Affiliation(s)
- İsmail Oltulu
- Department of Orthopedics and Traumatology, Emsey Hospital, İstanbul, Turkey
| | - Özgür Korkmaz
- Department of Orthopedics and Traumatology, Medicalpark Pendik Hospital, İstanbul, Turkey
| | - Ender Sarıoğlu
- Department of Orthopedics and Traumatology, Medicalpark Göztepe Hospital, İstanbul, Turkey
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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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Guo Z, Cui W, Sang DC, Sang HP, Liu BG. Clinical Relevance of Cervical Kinematic Quality Parameters in Planar Movement. Orthop Surg 2019; 11:167-175. [PMID: 30884156 PMCID: PMC6594496 DOI: 10.1111/os.12435] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 01/20/2019] [Accepted: 01/21/2019] [Indexed: 12/14/2022] Open
Abstract
Comprehending cervical spinal motion underlies the understanding of the mechanisms of cervical disorders. We aimed to better define the clinical relevance of cervical spine kinematics, focusing on quality parameters describing cervical spine planar motion. The most common study focuses were kinematic quality parameters after cervical arthroplasty and in normal subjects, patients with cervical degeneration, and patients with cervical deformities. Kinematic quality parameters are important for cervical degeneration prevention, being detected sooner than differences on imaging examinations and being significantly related to the degree of cervical degeneration. Kinematic quality parameters are effective for evaluating the changes of cervical motion pattern after cervical fusion and non‐fusion, assessing operative and adjacent segments in the early stages, and predicting adjacent segment degeneration. However, owing to current research limitations, and controversy about the changes of kinematic quality parameters after different surgical procedures, current assessments are limited to cervical spine flexion and extension. Different osteotomy methods of cervical deformity have different effects on cervical motion patterns and quality parameters. Choosing the most effective surgical method remains a challenge and kinematic quality parameters in cervical deformity are important future research topics. This review highlights the instantaneous center of rotation, the center of rotation, and the instantaneous axis of rotation as being important kinematic quality parameters of cervical spinal motion. These can be used to detect abnormal cervical mobility, to diagnose cervical degeneration, to design disc protheses, and to evaluate surgical effects earlier than other methods. Owing to limitations of research methods there is variation in the way parameters are defined by various researchers. No uniform standard exists for defining degenerative motion quality parameters in normal asymptomatic, degenerative, and postoperative patients. Therefore, further study is required. New study techniques and defining kinematic quality parameters in normal subjects will clarify the definitions of these parameters, enhancing their future clinical usefulness.
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Affiliation(s)
- Ze Guo
- Department of Orthopaedic Surgery, Beijing Tiantan Hospital, Capital Medical University, China National Clinical Research Center for Neurological Diseases, Beijing, China
| | - Wei Cui
- Department of Orthopaedic Surgery, Beijing Tiantan Hospital, Capital Medical University, China National Clinical Research Center for Neurological Diseases, Beijing, China
| | - Da-Cheng Sang
- Department of Orthopaedic Surgery, Beijing Tiantan Hospital, Capital Medical University, China National Clinical Research Center for Neurological Diseases, Beijing, China
| | - Hong-Peng Sang
- Department of Orthopaedic Surgery, Beijing Tiantan Hospital, Capital Medical University, China National Clinical Research Center for Neurological Diseases, Beijing, China
| | - Bao-Ge Liu
- Department of Orthopaedic Surgery, Beijing Tiantan Hospital, Capital Medical University, China National Clinical Research Center for Neurological Diseases, Beijing, China
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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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Guyer RD, Voronov LI, Havey RM, Khayatzadeh S, Carandang G, Blank KR, Werner S, Rubin J, Padovani N, Patwardhan AG. Kinematic assessment of an elastic-core cervical disc prosthesis in one and two-level constructs. JOR Spine 2018. [PMID: 31463455 DOI: 10.1002/jsp2.1040]] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Introduction Anterior cervical discectomy and fusion has been associated with the development of adjacent segment degeneration (ASD), with clinical incidence of approximately 3% per year. Cervical total disc arthroplasty (TDA) has been proposed as an alternative to prevent ASD. Hypotheses TDA in optimal placement using an elastic-core cervical disc (RHINE, K2M Inc., Leesburg, Virginia) will replicate natural kinematics and will improve with optimal vs anterior placement. Methods Seven C3-T1 cervical cadaver spines were tested intact first, then after one-level TDA at C5-C6 anterior placement, after TDA at C5-C6 optimal placement, after two-level TDA at C5-C6 and C6-C7 optimal placement, and finally after two-level TDA at C5-C6 lateral placement and C6-C7 optimal placement. The specimens were subjected to: Flexion-Extension moments (+1.5 Nm) with compressive preloads of 0 N and 150 N, lateral bending (LB) and axial rotation (AR) (+1.5 Nm) without preload. Results C5-C6 TDA in optimal placement resulted in a non-significant increase in flexion-extension ROM compared to intact under 0 N and 150 N preload (P > 0.05). Both LB and AR ROM decreased with arthroplasty (P < 0.01). Optimal placement of C6-C7 TDA resulted in an increase in flexion-extension ROM with preload compared to intact (P < 0.05) while LB and AR ROM decreased with arthroplasty (P < 0.01). Conclusion This six degree of freedom elastic-core disc arthroplasty effectively restored flexion-extension motion to intact levels. In LB the TDA maintained 42% ROM at C5-C6 and 60% at C6-C7. In AR 57% of the ROM was maintained at C5-C6 and 70% at C6-C7. These findings are supported by literature which shows cervical TDA results in restoration of approximately 50% ROM in LB and AR, which is a multifactorial phenomenon encompassing TDA design parameters and anatomical constraints. Anterior placement of this viscoelastic TDA device shows motion restoration similar to optimal placement suggesting its design may be less sensitive to suboptimal placement.
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Affiliation(s)
| | - Leonard I Voronov
- Loyola University Chicago Maywood Illinois.,Edward Hines Jr. VA Hospital Hines Illinois
| | - Robert M Havey
- Loyola University Chicago Maywood Illinois.,Edward Hines Jr. VA Hospital Hines Illinois
| | | | | | | | | | | | | | - Avinash G Patwardhan
- Loyola University Chicago Maywood Illinois.,Edward Hines Jr. VA Hospital Hines Illinois
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Guyer RD, Voronov LI, Havey RM, Khayatzadeh S, Carandang G, Blank KR, Werner S, Rubin J, Padovani N, Patwardhan AG. Kinematic assessment of an elastic-core cervical disc prosthesis in one and two-level constructs. JOR Spine 2018; 1:e1040. [PMID: 31463455 PMCID: PMC6686807 DOI: 10.1002/jsp2.1040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 10/31/2018] [Accepted: 11/01/2018] [Indexed: 11/12/2022] Open
Abstract
INTRODUCTION Anterior cervical discectomy and fusion has been associated with the development of adjacent segment degeneration (ASD), with clinical incidence of approximately 3% per year. Cervical total disc arthroplasty (TDA) has been proposed as an alternative to prevent ASD. HYPOTHESES TDA in optimal placement using an elastic-core cervical disc (RHINE, K2M Inc., Leesburg, Virginia) will replicate natural kinematics and will improve with optimal vs anterior placement. METHODS Seven C3-T1 cervical cadaver spines were tested intact first, then after one-level TDA at C5-C6 anterior placement, after TDA at C5-C6 optimal placement, after two-level TDA at C5-C6 and C6-C7 optimal placement, and finally after two-level TDA at C5-C6 lateral placement and C6-C7 optimal placement. The specimens were subjected to: Flexion-Extension moments (+1.5 Nm) with compressive preloads of 0 N and 150 N, lateral bending (LB) and axial rotation (AR) (+1.5 Nm) without preload. RESULTS C5-C6 TDA in optimal placement resulted in a non-significant increase in flexion-extension ROM compared to intact under 0 N and 150 N preload (P > 0.05). Both LB and AR ROM decreased with arthroplasty (P < 0.01). Optimal placement of C6-C7 TDA resulted in an increase in flexion-extension ROM with preload compared to intact (P < 0.05) while LB and AR ROM decreased with arthroplasty (P < 0.01). CONCLUSION This six degree of freedom elastic-core disc arthroplasty effectively restored flexion-extension motion to intact levels. In LB the TDA maintained 42% ROM at C5-C6 and 60% at C6-C7. In AR 57% of the ROM was maintained at C5-C6 and 70% at C6-C7. These findings are supported by literature which shows cervical TDA results in restoration of approximately 50% ROM in LB and AR, which is a multifactorial phenomenon encompassing TDA design parameters and anatomical constraints. Anterior placement of this viscoelastic TDA device shows motion restoration similar to optimal placement suggesting its design may be less sensitive to suboptimal placement.
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Affiliation(s)
| | - Leonard I. Voronov
- Loyola University ChicagoMaywoodIllinois
- Edward Hines Jr. VA HospitalHinesIllinois
| | - Robert M. Havey
- Loyola University ChicagoMaywoodIllinois
- Edward Hines Jr. VA HospitalHinesIllinois
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Jonas R, Demmelmaier R, Hacker SP, Wilke HJ. Comparison of three-dimensional helical axes of the cervical spine between in vitro and in vivo testing. Spine J 2018; 18:515-524. [PMID: 29074465 DOI: 10.1016/j.spinee.2017.10.065] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 09/28/2017] [Accepted: 10/16/2017] [Indexed: 02/03/2023]
Abstract
BACKGROUND CONTEXT The range of motion is a well-accepted parameter for the assessment and evaluation of cervical motion. However, more qualitative data of the kinematics of the cervical spine are needed for the development and success of cervical disc arthroplasty. PURPOSE The aim of this study was to provide basic information about helical axes of human cervical spine under in vitro conditions. Furthermore, it should clarify whether the three-dimensional helical axes of cervical motion gained from in vitro experiments are in agreement with those gained from in vivo experiments, and therefore to prove its reliability. STUDY DESIGN/SETTING An in vitro test with pure moments and mono-segmental specimens was designed to investigate and compare the helical axes of the cervical spine. METHODS Six human cadaveric specimens (three male and three female) with an average age of 47.5 years (range: 34-58 years) were carefully selected. Each specimen was divided into three motion segments: C2-C3, C4-C5, and C6-C7. We performed 3.5 full cycles of rotation about all axes, flexion-extension, lateral bending, and axial rotation, by applying pure moments of 1.5 Nm without any preload. Following the in vitro tests, the three-dimensional helical axes were calculated and projected into the x-ray images. RESULTS Rotation analysis of all three directions revealed similar results for all six specimens. All calculated helical axes were similar to the published in vivo data. Furthermore, the instantaneous centers of rotation were in agreement with in vivo data. CONCLUSIONS The data gained from this study verify cervical kinematics during in vitro testing using pure moments. It can be assumed that other soft tissue such as muscles are not necessarily needed to simulate cervical kinematics in vitro.
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Affiliation(s)
- René Jonas
- Institute of Orthopaedic Research and Biomechanics, Centre for Trauma Research Ulm, Ulm University, Helmholtzstraße 14, 89081 Ulm, Germany
| | - Robert Demmelmaier
- Institute of Orthopaedic Research and Biomechanics, Centre for Trauma Research Ulm, Ulm University, Helmholtzstraße 14, 89081 Ulm, Germany
| | - Steffen P Hacker
- Institute of Orthopaedic Research and Biomechanics, Centre for Trauma Research Ulm, Ulm University, Helmholtzstraße 14, 89081 Ulm, Germany
| | - Hans-Joachim Wilke
- Institute of Orthopaedic Research and Biomechanics, Centre for Trauma Research Ulm, Ulm University, Helmholtzstraße 14, 89081 Ulm, Germany.
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Are Collapsed Cervical Discs Amenable to Total Disc Arthroplasty?: Analysis of Prospective Clinical Data With 2-Year Follow Up. Spine (Phila Pa 1976) 2016; 41:1866-1875. [PMID: 27434178 DOI: 10.1097/brs.0000000000001793] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Analysis of prospectively collected radiographic data. OBJECTIVE To investigate the influence of preoperative index-level range of motion (ROM) and disc height on postoperative ROM after cervical total disc arthroplasty (TDA) using compressible disc prostheses. SUMMARY OF BACKGROUND DATA Clinical studies demonstrate benefits of motion preservation over fusion; however, questions remain unanswered as to which preoperative factors have the ability to identify patients who are most likely to have good postoperative motion, which is the primary rationale for TDA. METHODS We analyzed prospectively collected data from a single-arm, multicenter study with 2-year follow up of 30 patients with 48 implanted levels. All received compressible cervical disc prostheses of 6 mm-height (M6C, Spinal Kinetics, Sunnyvale, CA). The influence of index-level preoperative disc height and ROM (each with two levels: below-median and above-median) on postoperative ROM was analyzed using 2 x 2 ANOVA. We further analyzed the radiographic outcomes of a subset of discs with preoperative height less than 3 mm, the so-called "collapsed" discs. RESULTS Shorter (3.0 ± 0.4 mm) discs were significantly less mobile preoperatively than taller (4.4 ± 0.5 mm) discs (6.7° vs. 10.5°, P = 0.01). The postoperative ROM did not differ between the shorter and taller discs (5.6° vs. 5.0°, P = 0.63). Tall discs that were less mobile preoperatively had significantly smaller postoperative ROM than short discs with above-median preoperative mobility (P < 0.05). The "collapsed discs" (n = 8) were less mobile preoperatively compared with all discs combined (5.1° vs. 8.6°, P < 0.01). These discs were distracted to more than two times the preoperative height, from 2.6 to 5.7 mm, and had significantly greater postoperative ROM than all discs combined (7.6° vs. 5.3°, P < 0.05). CONCLUSION We observed a significant interaction between preoperative index-level disc height and ROM in influencing postoperative ROM. Although limited by small sample size, the results suggest discs with preoperative height less than 3 mm may be amenable to disc arthroplasty using compressible disc prostheses. LEVEL OF EVIDENCE 2.
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Onken J, Reinke A, Radke J, Finger T, Bayerl S, Vajkoczy P, Meyer B. Revision surgery for cervical artificial disc: Surgical technique and clinical results. Clin Neurol Neurosurg 2016; 152:39-44. [PMID: 27888676 DOI: 10.1016/j.clineuro.2016.10.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Revised: 10/23/2016] [Accepted: 10/29/2016] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Cervical artificial disc replacement (C-ADR) was developed with the goal of preserving mobility of the cervical segment in patients with degenerative disc disease. So far, little is known about experiences with revision surgery and explantation of C-ADRs. Here, we report our experience with revision the third generation, Galileo-type disc prosthesis from a retrospective study of two institutions. PATIENTS AND METHODS Between November 2008 and July 2016, 16 patients with prior implantation of C-ADR underwent removal of the Galileo-type disc prosthesis (Signus, Medizintechnik, Germany) due to a call back by industry. In 10 patients C-ADR was replaced with an alternative prosthesis, 6 patients received an ACDF. Duration of surgery, time to revision, surgical procedure, complication rate, neurological status, histological findings and outcome were examined in two institutions. RESULTS The C-ADR was successfully revised in all patients. Surgery was performed through the same anterior approach as the initial access. Duration of the procedure varied between 43 and 80min. Access-related complications included irritation of the recurrent nerve in one patient and mal-positioning of the C-ADR in another patient. Follow up revealed two patients with permanent mild/moderate neurologic deficits, NDI (neck disability index) ranged between 10 and 42%. CONCLUSIONS Anterior exposure of the cervical spine for explantation and revision of C-ADR performed through the initial approach has an overall complication rate of 18.75%. Replacements of the Galileo-type disc prosthesis with an alternative prosthesis or conversion to ACDF are both suitable surgical options without significant difference in outcome.
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Affiliation(s)
- J Onken
- Department of Neurosurgery, Charité, Berlin, Germany
| | - A Reinke
- Department of Neurosurgery, TMU, Munich, Germany
| | - J Radke
- Department of Neuropathology, Charité, Berlin, Germany
| | - T Finger
- Department of Neurosurgery, Charité, Berlin, Germany
| | - S Bayerl
- Department of Neurosurgery, Charité, Berlin, Germany
| | - P Vajkoczy
- Department of Neurosurgery, Charité, Berlin, Germany.
| | - B Meyer
- Department of Neurosurgery, TMU, Munich, Germany
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Abstract
STUDY DESIGN Retrospective study. OBJECTIVE To determine the short-term clinical succesrate of the M6-C cervical disk prosthesis in primary and secondary surgery. SUMMARY OF BACKGROUND DATA Cervical disk arthroplasty (CDA) provides an alternative to anterior cervical decompression and fusion for the treatment of spondylotic radiculopathy or myelopathy. The prevention of adjacent segment disease (ASD), a possible complication of anterior cervical decompression and fusion, is its most cited--although unproven--benefit. Unlike older arthroplasty devices that rely on a ball-and-socket-type design, the M6-C cervical disk prosthesis represents a new generation of unconstrained implants, developed to achieve better restoration of natural segmental biomechanics. This device should therefore optimize clinical performance of CDA and reduce ASD. MATERIALS AND METHODS All patients had preoperative computed tomography or magnetic resonance imaging and postoperative x-rays. Clinical outcome was assessed using the Neck Disability Index, a Visual Analog Scale, and the SF-36 questionnaire. Patients were asked about overall satisfaction and whether they would have the surgery again. RESULTS Thirty-three patients were evaluated 17.1 months after surgery, on average. Nine patients had a history of cervical interventions. Results for Neck Disability Index, Visual Analog Scale, and SF-36 were significantly better among patients who had undergone primary surgery. In this group, 87.5% of patients reported a good or excellent result and 91.7% would have the procedure again. In contrast, all 4 device-related complications occurred in the small group of patients who had secondary surgery. CONCLUSIONS The M6-C prosthesis appears to be a valuable addition to the CDA armatorium. It generates very good results in patients undergoing primary surgery, although its use in secondary surgery should be avoided. Longer follow-up is needed to determine to what measure this device can prevent ASD.
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Welke B, Schwarze M, Hurschler C, Book T, Magdu S, Daentzer D. In vitro investigation of a new dynamic cervical implant: comparison to spinal fusion and total disc replacement. 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 2015; 25:2247-54. [PMID: 26684468 DOI: 10.1007/s00586-015-4361-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 12/07/2015] [Accepted: 12/07/2015] [Indexed: 12/28/2022]
Abstract
PURPOSE AND METHODS For the treatment of degenerative disc diseases of the cervical spine, anterior cervical discectomy and fusion (ACDF) still represents the standard procedure. However, long term clinical studies have shown a higher incidence of pathologies in the adjacent segments. As an alternative to spinal fusion, cervical total disc replacement (cTDR) or dynamically implants were increasingly used. This in vitro study analyzed the kinematics and intradiscal pressures in seven multi-segmental human cervical spine using hybrid multidirectional test method. The aim of our study was to compare the intact condition with a single-level dynamic stabilization with DCI(®), with cTDR (activC(®)) and with simulated ACDF (CeSPACE(®) cage and CASPAR plate). RESULTS No significant changes in the kinematics and pressures were observed in all segments after arthroplasty. The DCI(®) significantly decreased the motion of the treated segment in flexion/extension and lateral bending with some remaining residual mobility. Thereby the motion of the upper segment was increased significantly in flexion/extension. No significant changes of the intradiscal pressures were observed. With simulated fusion the motion of the indexed level was significantly decreased in flexion/extension and axial rotation with the greatest changes in the adjacent levels and the highest pressures. CONCLUSION Based on our biomechanical study the DCI(®) can pose an alternative to fusion, which has a lesser effect on adjacent levels. This might reduce the risk of long-term degeneration in those levels. In particular, the facet joint arthritis and kyphotic deformity, as a contraindication to the arthroplasty, could be a clinical application of the dynamic implant.
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Affiliation(s)
- Bastian Welke
- Laboratory for Biomechanics and Biomaterials, Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Str. 1-7, 30625, Hannover, Germany.
| | - Michael Schwarze
- Laboratory for Biomechanics and Biomaterials, Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Str. 1-7, 30625, Hannover, Germany
| | - Christof Hurschler
- Laboratory for Biomechanics and Biomaterials, Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Str. 1-7, 30625, Hannover, Germany
| | - Thorsten Book
- Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Str. 1-7, 30625, Hannover, Germany
| | - Stephan Magdu
- Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Str. 1-7, 30625, Hannover, Germany
| | - Dorothea Daentzer
- Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Str. 1-7, 30625, Hannover, Germany
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Shi JS, Lin B, Xue C, Zhang HS, Chen ZD, Zhao ZS. Clinical and radiological outcomes following hybrid surgery in the treatment of multi-level cervical spondylosis: over a 2-year follow-up. J Orthop Surg Res 2015; 10:185. [PMID: 26684799 PMCID: PMC4683912 DOI: 10.1186/s13018-015-0330-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 12/02/2015] [Indexed: 11/12/2022] Open
Abstract
Background The optimal surgical approach for treatment of multi-level cervical disc disease is currently widely debated. Anterior cervical discectomy and fusion (ACDF) combined with cervical disc arthroplasty (CDA) has been presented as a treatment approach, but to date, there are few reports with adequate clinical and radiological data for this hybrid surgical procedure. The goal of this paper is to assess clinical and radiological outcomes in patients with cervical spondylosis in three contiguous segments after treatment with artificial disc replacement combined with fusion. Materials and methods We performed a retrospective review of 36 patients (mean age of 48.6 years) with contiguous three-level cervical spondylosis who were treated with ACDF coupled with CDA (hybrid surgery) between October 2008 and October 2012. Clinical evaluation was based on the Neck Disability Index (NDI), Japanese Orthopaedic Association (JOA) score, and postoperative JOA score improvement rate (IR). Radiographic parameters, angular range of motion (ROM) for C2-C7, and ROM for the superior and inferior adjacent segments were measured before the operation, at 1, 3, 6, and 12 months postoperation, and at the final follow-up evaluation. All cases were followed for at least 28 months (range 28–65 months). Results All patients exhibited significant postoperative improvement in NDI and JOA scores compared to preoperative levels (P < 0.05), and these improved scores were maintained during the follow-up period. The JOA score improvement rate was 70.83 % at the final follow-up evaluation. The mean C2-C7 ROM of all cases was significantly decreased immediately after operation but recovered to preoperative levels after 12 months (P = 0.721). The ROM of the superior and inferior adjacent segments was recovered to preoperative levels after 6 months (P > 0.05). One patient required a second surgery for symptomatic adjacent segment degeneration. Neither pseudarthrosis nor other device migration was observed in any patients during the entire follow-up period. Conclusions These results indicate that hybrid surgery seems to be a promising, acceptable, and alternative surgical approach for the treatment of multi-level cervical disc disease.
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Affiliation(s)
- Ji-Sheng Shi
- Department of Orthopedics, Hospital of Orthopedics, The 175th Hospital of PLA, Southeast Hospital of Xiamen University, No. 269 Zhanghua Road, Zhangzhou, 363000, Fujian, People's Republic of China
| | - Bin Lin
- Department of Orthopedics, Hospital of Orthopedics, The 175th Hospital of PLA, Southeast Hospital of Xiamen University, No. 269 Zhanghua Road, Zhangzhou, 363000, Fujian, People's Republic of China.
| | - Chao Xue
- Department of Orthopedics, Hospital of Orthopedics, The 175th Hospital of PLA, Southeast Hospital of Xiamen University, No. 269 Zhanghua Road, Zhangzhou, 363000, Fujian, People's Republic of China
| | - Hai-Shen Zhang
- Department of Orthopedics, Hospital of Orthopedics, The 175th Hospital of PLA, Southeast Hospital of Xiamen University, No. 269 Zhanghua Road, Zhangzhou, 363000, Fujian, People's Republic of China
| | - Zhi-Da Chen
- Department of Orthopedics, Hospital of Orthopedics, The 175th Hospital of PLA, Southeast Hospital of Xiamen University, No. 269 Zhanghua Road, Zhangzhou, 363000, Fujian, People's Republic of China
| | - Zhong-Sheng Zhao
- Department of Orthopedics, Hospital of Orthopedics, The 175th Hospital of PLA, Southeast Hospital of Xiamen University, No. 269 Zhanghua Road, Zhangzhou, 363000, Fujian, People's Republic of China
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Abstract
STUDY DESIGN A biomechanical study using human spine specimens. OBJECTIVE To study postural compensations in lordosis angles that are necessary to maintain horizontal gaze in the presence of forward head posture and increasing T1 sagittal tilt. SUMMARY OF BACKGROUND DATA Forward head posture relative to the shoulders, assessed radiographically using the horizontal offset distance between the C2 and C7 vertebral bodies (C2-C7 [sagittal vertical alignment] SVA), is a measure of global cervical imbalance. This may result from kyphotic alignment of cervical segments, muscle imbalance, as well as malalignment of thoracolumbar spine. METHODS Ten cadaveric cervical spines (occiput-T1) were tested. The T1 vertebra was anchored to a tilting and translating base. The occiput was free to move vertically but its angular orientation was constrained to ensure horizontal gaze regardless of sagittal imbalance. A 5-kg mass was attached to the occiput to mimic head weight. Forward head posture magnitude and T1 tilt were varied and motions of individual vertebrae were measured to calculate C2-C7 SVA and lordosis across C0-C2 and C2-C7. RESULTS Increasing C2-C7 SVA caused flexion of lower cervical (C2-C7) segments and hyperextension of suboccipital (C0-C1-C2) segments to maintain horizontal gaze. Increasing kyphotic T1 tilt primarily increased lordosis across the C2-C7 segments. Regression models were developed to predict the compensatory C0-C2 and C2-C7 angulation needed to maintain horizontal gaze given values of C2-C7 SVA and T1 tilt. CONCLUSION This study established predictive relationships between radiographical measures of forward head posture, T1 tilt, and postural compensations in the cervical lordosis angles needed to maintain horizontal gaze. The laboratory model predicted that normalization of C2-C7 SVA will reduce suboccipital (C0-C2) hyperextension, whereas T1 tilt reduction will reduce the hyperextension in the C2-C7 segments. The predictive relationships may help in planning corrective strategy in patients experiencing neck pain, which may be attributed to sagittal malalignment. LEVEL OF EVIDENCE N/A.
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Brenke C, Schmieder K, Barth M. Core herniation after implantation of a cervical artificial disc: case report. 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 2014; 24 Suppl 4:S536-9. [PMID: 25404371 DOI: 10.1007/s00586-014-3677-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 11/07/2014] [Accepted: 11/13/2014] [Indexed: 01/12/2023]
Abstract
INTRODUCTION Cervical artificial discs (CADs) represent an established surgical option in selected patients with cervical spinal disc degeneration. Though CADs have been available for many years, there is a lack of information concerning long-term safety, durability and implant-related failure rates. MATERIALS AND METHODS The authors describe the failure of a M6-C CAD (Spinal Kinetics, Sunnyvale, CA, USA). RESULTS Eight years after implantation of a CAD of the M6 type, a 39-year-old female presented with new clinical signs of cervical myelopathy. Radiologically, medullar compression due to posterior core herniation was the suspected cause. The damaged CAD was removed and the segment fused. During revision surgery, rupture of the posterior structures could be detected. Possible mechanisms leading to implant failure are discussed. CONCLUSION As there is no standard regarding clinical and radiological follow-up for patients with CADs, radiological long-term follow-up investigations seem to be justified for exclusion of implant failure.
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Affiliation(s)
- Christopher Brenke
- Department of Neurosurgery, Knappschaftskrankenhaus Bochum, Ruhr-University of Bochum, In der Schornau 23-25, 44892, Bochum, Germany,
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Koller H, Meier O, Zenner J, Mayer M, Hitzl W. In vivo analysis of cervical kinematics after implantation of a minimally constrained cervical artificial disc replacement. 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 2013; 22:747-58. [PMID: 23179982 PMCID: PMC3631039 DOI: 10.1007/s00586-012-2583-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 09/15/2012] [Accepted: 11/07/2012] [Indexed: 12/12/2022]
Abstract
INTRODUCTION To better understand cervical kinematics following cervical disc replacement (CDR), the in vivo behavior of a minimally constrained CDR was assessed. METHODS Radiographic analysis of 19 patients undergoing a 1-level CDR from C4-5 to C6-7 (DISCOVER, Depuy-Spine, USA) was performed. Neutral-lateral and flexion-extension radiographs obtained at preop, postop and late follow-up were analyzed for segmental angle and global angle (GA C2-7). Flexion-extension range of motion was analyzed using validated quantitative motion analysis software (QMA®, Medical Metrics, USA). The FSU motion parameters measured at the index and adjacent levels were angular range of motion (ROM), translation and center of rotation (COR). Translation and COR were normalized to the AP dimension of the inferior endplate of the caudal vertebra. All motion parameters, including COR, were compared with normative reference data. RESULTS The average patient age was 43.5 ± 7.3 years. The mean follow-up was 15.3 ± 7.2 months. C2-7 ROM was 35.9° ± 15.7° at preop and 45.4° ± 13.6° at follow-up (∆p < .01). Based on the QMA at follow-up, angular ROM at the CDR level measured 9.8° ± 5.9° and translation was 10.1 ± 7.8 %. Individuals with higher ROM at the CDR level had increased translation at that level (p < .001, r = 0.97), increased translation and ROM at the supra-adjacent level (p < .001, r = .8; p = .005, r = .6). There was a strong interrelation between angular ROM and translation at the supra-adjacent level (p < .001, r = .9) and caudal-adjacent level (p < .001, r = .9). The location of the COR at the CDR- and supra-adjacent levels was significantly different for the COR-X (p < .001). Notably, the COR-Y at the CDR level was significantly correlated with the extent of CDR-level translation (p = .02, r = .6). Shell angle, which may be influenced by implant size and positioning had no impact on angular ROM but was correlated with COR-X (p = .05, r = -.6) and COR-Y (p = .04, r = -.5). CONCLUSION The COR is an important parameter for assessing the ability of non-constrained CDRs to replicate the normal kinematics of a FSU. CDR size and location, both of which can impact shell angle, may influence the amount of translation by affecting the location of the COR. Future research is needed to show how much translation is beneficial concerning clinical outcomes and facet loading.
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Affiliation(s)
- Heiko Koller
- Werner Wicker Clinic, German Scoliosis Center Bad Wildungen, Im Kreuzfeld 4, 34537 Bad Wildungen, Germany.
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Lauryssen C, Coric D, Dimmig T, Musante D, Ohnmeiss DD, Stubbs HA. Cervical total disc replacement using a novel compressible prosthesis: Results from a prospective Food and Drug Administration-regulated feasibility study with 24-month follow-up. Int J Spine Surg 2012; 6:71-7. [PMID: 25694874 PMCID: PMC4300885 DOI: 10.1016/j.ijsp.2012.02.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Background Anterior cervical fusion, an established procedure to treat cervical radiculopathy, sacrifices the natural function of the disc, while placing increased stresses on adjacent spinal levels. In contrast, the cervical total disc replacement (cTDR) maintains motion and decreases adjacent-level stresses. The purpose of this study was to investigate the safety and effectiveness of a next-generation cTDR device in patients with symptomatic cervical radiculopathy. Methods This is a multicenter Food and Drug Administration–regulated feasibility study to evaluate safety and effectiveness of the M6-C Artificial Cervical Disc for the treatment of patients with symptomatic cervical radiculopathy at 1 or 2 levels from C3 to C7. Neck Disability Index (NDI), visual analog scales (VAS) assessing neck and arm pain, Short Form 36 Health Survey (SF-36), safety, and radiographic outcomes were assessed preoperatively, at 6 weeks and 3, 6, 12, and 24 months postoperatively. Results Thirty patients were enrolled at 3 clinical sites. Patients were implanted at either 1 or 2 levels. Mean NDI improved from 67.8 to 20.8 (P < .0001) at 24 months. Significant improvement was also observed through 24-month follow-up in neck and arm pain VAS (P < .0001) and in physical (P < .005) and mental component scores of the SF-36 at 3, 6, and 12 months (P < .008). There were no serious adverse events related to the device or procedure as adjudicated by an independent clinical events committee. Radiographically, disc space height increased more than 50% with a correlative increase in the postoperative disc angle. Range of motion decreased slightly from baseline during early follow-up but increased slightly and were maintained throughout the follow-up period. Conclusions The M6-C cervical artificial disc represents a new generation of cTDR design. Results of this study found the M6-C device to produce positive clinical and radiographic outcomes similar to other cTDRs, warranting further investigation.
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Affiliation(s)
- Carl Lauryssen
- Institute for Advanced Spinal Research in California, Beverly Hills, CA
| | - Domagoj Coric
- Carolina Neurosurgery and Spine Associates, Charlotte, NC
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