The Feasibility of Optimal Surgical Result Prediction according to the Centre of Rotation Shift after Multilevel Cervical Total Disc Replacement

2018 ◽  
Vol 1 (2) ◽  
pp. 6
Author(s):  
Jun Ho Lee

Objective: This study investigates the relation between shifted locations of centre of rotation (COR) at each cervical level and subsequent surgical outcomes after multilevel cervical total disc replacement (MCTDR) and identifies radiological parameter that corresponded to change of COR after MCTDR. Methods: The study included a consecutive series of 24 patients who were treated with MCTDR following diagnosis of multilevel cervical disc herniation or stenosis. Numeric rating scale (NRS), range of motion (ROM) at both C2-7 segment and TDR implanted levels, and the location of COR at TDR implanted level were evaluated at pre- and post-MCTDR. These parameters were compared between patients who experienced successful and unsuccessful pain relief.Results: The inherent CORs relatively at ventro-cranial coordinates have demonstrated significant migrations to dorso-caudal locations at each cervical levels, more prominent shifts for the successful group, after MCTDR switch. The unsuccessful group showed markedly reduced C2-7 ROM and reduced angular improvement at C2-7 as well as MCTDR level after surgery in comparison with the successful group. Postoperative C2-7 ROM was related to postoperative COR along the X-axis.Conclusions: The crucial determinants for clinical success after MCTDR, other than mere preservation of the ROM both at C2-7 and TDR implanted levels, was the restoration of COR from ventro-cranial location at degenerated cervical motion segment close to normal coordinates by posterior and inferior shifts after MCTDR. The position of COR along the X-axis after MCTDR was an important factor to determine maintenance of C2-7 RO.

2020 ◽  
Vol 14 (4) ◽  
pp. 445-452
Author(s):  
Jung Hwan Lee ◽  
Jun Ho Lee

Study Design: Retrospective design/spine clinic and tertiary referral hospital.Purpose: This study investigated the association between shifted location of center of rotation (COR) and subsequent surgical outcomes and identified radiological parameters that corresponded to COR change after multilevel cervical total disc replacement (MCTDR).Overview of Literature: Cervical total disc replacement (TDR) maintains normal cervical kinematics after surgery. However, there is a paucity of literature analyzing the relationship between radiological shifts of COR and subsequent clinical success, especially when it comes to the issue of MCTDR switch.Methods: This study included 24 consecutive patients treated with MCTDR following the diagnosis of multilevel cervical disc herniation or stenosis. Numeric rating scale, range of motion (ROM) at both C2–7 segment and TDR implanted levels, and location of COR at TDR level were evaluated pre- and post-MCTDR. These parameters were compared between patients who experienced successful and unsuccessful pain relief.Results: The inherent CORs relatively at ventrocranial coordinates demonstrated significant migrations to dorsocaudal location, more prominent shifts for the successful group, after MCTDR switch. The unsuccessful group showed markedly reduced C2–7 ROM and reduced angular improvement at C2–7 segment and MCTDR level compared with the successful group. Postoperative C2–7 ROM was related to postoperative COR along the x-axis.Conclusions: Aside from ROM preservation at both C2–7 and TDR levels, COR restoration from ventrocranial location close to normal coordinates by posterior and inferior shifts was marked as a clinical success after MCTDR. The COR position along the x-axis after MCTDR was an important factor to determine maintenance of C2–7 ROM.


Author(s):  
Matthew Scott-Young ◽  
Evelyne Rathbone ◽  
Lauren Grierson

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.


2016 ◽  
Vol 25 (2) ◽  
pp. 213-224 ◽  
Author(s):  
Kris Radcliff ◽  
Domagoj Coric ◽  
Todd Albert

OBJECTIVE The purpose of this study was to report the outcome of a study of 2-level cervical total disc replacement (Mobi-C) versus anterior cervical discectomy and fusion (ACDF). Although the long-term outcome of single-level disc replacement has been extensively described, there have not been previous reports of the 5-year outcome of 2-level cervical disc replacement. METHODS This study reports the 5-year results of a prospective, randomized US FDA investigational device exemption (IDE) study conducted at 24 centers in patients with 2-level, contiguous, cervical spondylosis. Clinical outcomes at up to 60 months were evaluated, including validated outcome measures, incidence of reoperation, and adverse events. The complete study data and methodology were critically reviewed by 3 independent surgeon authors without affiliation with the IDE study or financial or institutional bias toward the study sponsor. RESULTS A total of 225 patients received the Mobi-C cervical total disc replacement device and 105 patients received ACDF. The Mobi-C and ACDF follow-up rates were 90.7% and 86.7%, respectively (p = 0.39), at 60 months. There was significant improvement in all outcome scores relative to baseline at all time points. The Mobi-C patients had significantly more improvement than ACDF patients in terms of Neck Disability Index score, SF-12 Physical Component Summary, and overall satisfaction with treatment at 60 months. The reoperation rate was significantly lower with Mobi-C (4%) versus ACDF (16%). There were no significant differences in the adverse event rate between groups. CONCLUSIONS Both cervical total disc replacement and ACDF significantly improved general and disease-specific measures compared with baseline. However, there was significantly greater improvement in general and disease-specific outcome measures and a lower rate of reoperation in the 2-level disc replacement patients versus ACDF control patients. Clinical trial registration no. NCT00389597 (clinicaltrials.gov)


Spine ◽  
2019 ◽  
Vol 44 (1) ◽  
pp. 79-83 ◽  
Author(s):  
Dale N. Segal ◽  
Jacob M. Wilson ◽  
Christopher Staley ◽  
S. Tim Yoon

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