2118 European Versus North American Results in Secondary Surgery After Cervical Arthroplasty Versus ACDF: Meta-analysis of RCTs

INTRODUCTION: Cervical disc arthroplasty (CDA) and anterior cervical discectomy and fusion (ACDF) are both treatment options for patients with cervical degenerative disc disease. Prior studies have demonstrated lower rates of adjacent segment degeneration (ASD) and secondary surgery after CDA compared to ACDF, yet the geographic differences in prior randomized controlled trial (RCT) data are unclear. METHODS: Two independent reviewers searched PubMed, Embase, and the Cochrane Library for RCTs comparing CDA and ACDF for cervical degenerative disc disease with at least 60 months of clinical follow-up. We then grouped study results based on European or North American study population. The risk ratio or standardized mean difference (and 95% CIs) were calculated for secondary surgery, NDI, VAS neck and VAS arm scores. RESULTS: A total of 5 RCTs were included for analysis published between 2014-2023. Two studies were performed in Europe and 3 were performed in North America. The North American RCTs were more likely to be industry-sponsored. The pooled North American RCT analysis showed a significant benefit of CDA over ACDF for ASD requiring secondary surgery (combined OR 0.47, 95% CI 0.32-0.70, p=0.0002), whereas no difference was seen in the analysis of European RCTs (OR 0.46, 95% CI 0.07-2.89, p=0.40). No differences in NDI or VAS neck or arm scores were observed between regions. When the RCTs with at least 60 month follow-up were combined, European RCTs had statistically higher rates of postoperative follow-up in ACDF patients vs. North American RCTs (p=0.03). CONCLUSIONS: The results of this meta analysis of RCT data from North America and Europe comparing CDA vs. ACDF suggest that North American RCTs were more likely to demonstrate a positive benefit of CDA over ACDF for ASD requiring secondary surgery, were more likely to be industry-sponsored, and more likely to have lower postoperative follow-up rates.