P75. Range of motion on flexion and extension at long term followup after cervical total disc arthroplasty: a systematic review and meta-analysis

Abstract

<h3>BACKGROUND CONTEXT</h3> As an alternative procedure to anterior cervical discectomy and fusion (ACDF), total disc arthroplasty (TDA) facilitates direct neural decompression and disc height restoration while also preserving cervical spine kinematics. To date, few studies have reported long-term functional outcomes following TDA. <h3>PURPOSE</h3> This study sought to perform a systematic review and meta-analysis investigating how range of motion (ROM) at the operative level is maintained with long-term followup. <h3>STUDY DESIGN/SETTING</h3> Systematic review and meta-analysis <h3>PATIENT SAMPLE</h3> Patients in the literature of prospective studies of 1-level cervical TDA with a minimum of 5 years followup. <h3>OUTCOME MEASURES</h3> Segmental ROM at the preoperative, 1 year postoperative, and final (>5 years) postoperative time points. <h3>METHODS</h3> PubMed and MEDLINE were queried for all published studies pertaining to cervical TDA. The methodology for screening adhered strictly to the PRISMA guidelines. All English language prospective studies reporting ROM preoperatively, one year postoperatively, and/or at long-term follow-up of 5 or more years were included. A meta-analysis was performed using Cochran's Q and I2 to test data for statistical heterogeneity, in which case a random-effects model was used. The mean difference (MD) and associated 95% confidence intervals (CI) were reported. <h3>RESULTS</h3> After an initial search yielding 2,309 results, 12 studies met the inclusion criteria and 8 were included for meta-analysis. Overall, 1,158 patients were enrolled across the 8 studies and 944 (81.52%) were available for long-term followup. Of the patients who followed up, 163 (17.27%) were implanted with PCM, 131 (13.88%) with Mobi-C, 184 (19.49%) with Secure-C, 230 (24.36%) with Prestige LP, 229 (24.26%) with Bryan, and 27 (2.86%) with ProDisc-C prostheses. There was no difference found between operative segment ROM on flexion and extension preoperatively and at 1-year followup (MD = -0.91, CI: -3.07 to 1.25, p = .410). However, after excluding one study identified to contribute significantly to statistical heterogeneity via sensitivity analysis, ROM was found to significantly improve at 1-year postoperatively (MD = 1.92, CI: -2.79 to -1.04, p < .0001). There was no difference between ROM preoperatively and at long-term followup (MD = 0.52, CI: -0.98 to 2.03, p = .500). However, there was a significant decrease in ROM from 1-year postoperatively to final long-term followup (MD = 0.77, CI: 0.24 to 1.29, p = .004). <h3>CONCLUSIONS</h3> Operative segment ROM on flexion and extension was found to significantly deteriorate with long-term followup after TDA when compared to the early postoperative period. However, ROM on flexion and extension in the long-term following TDA remained similar to baseline function. While additional studies with further longitudinal follow-up investigating how much are needed, these findings further support the notion that cervical TDA may be successful in maintaining physiological spinal kinematics over the long-term. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.