174 Comparison of 7-Year Results of One-Level versus Two-Level Cervical Disc Arthroplasty and Fusion

Abstract

INTRODUCTION
Two independent clinical trials concluded that cervical disc arthroplasty (CDA) is as safe and effective as anterior cervical discectomy and fusion (ACDF) for treating cervical disc disease (CDD) at one and two levels. This study compared the safety and effectiveness at 7-year follow-up for subjects treated with CDA versus ACDF at 1 and 2-levels.

METHODS
Retrospective analysis of combined data from 1 and 2-level FDA IDE clinical trials. Outcomes were compared between 1-level and 2-level CDA and ACDF subjects. Propensity score method was used for an adjusted means analysis.

RESULTS
>There were no preoperative differences between 1 and 2-level CDA and ACDF patients for NDI, neck/arm pain, and SF-36 PCS. Comparing 1 vs 2-level CDA: there were no differences between 1 and 2-level CDA for NDI improvement (38.2 vs 39.0, P = 0.768), neck pain (11.7 vs 12.3, P = 0.374), arm pain (11.3 vs 11.0, P = 0.736), SF-36 PCS (12.6 vs 14.5, P = 0.220), or rates of neurological success (92.8% vs 91.6%, P = 0.867). Secondary surgeries were numerically higher for 1-than 2-level CDA at index and adjacent levels (7.3% vs 4.2%, P = 0.566) and (11.6% vs 6.5%, P = 0.056) respectively. Rates of serious AEs were significantly higher for 1 than 2-level CDA (67.8% vs 56.7%, P = 0.004). Comparison of 1 vs 2-level ACDF: there were no differences between 1 and 2-level ACDF for NDI improvement (31.1 vs 31.6, P = 0.859), neck pain (9.7 vs 9.9, P = 0.796), arm pain (9.9 vs 10.1, P = 0.848), SF-36 PCS (10.8 vs 12.1, P = 0.424), rates of neurological success (79.7% vs 82.1%, P = 0.421), or rates of secondary surgeries at index levels (13.6% vs 14.7%, P = 0.631) or adjacent levels (10.9% vs 12.5%, P = 0.366). Rates of serious AEs were similar for 1 and 2-level ACDF (61.8% vs 68.2%, P = 0.200) but rates of all AEs (94.5% vs 98.2%, P < 0.001) and device-related AEs (18.9% vs. 27.7%, P = 0.036) were significantly lower for 1 versus 2-level ACDF.

CONCLUSION
One and 2-level CDA appear to be equally safe and effective in the treatment of CDD at 7-years. Two-level ACDF was equally effective as 1-level, but 2-level ACDF had a higher rate of device-related AEs.