Reoperation Risks Between Cervical Disc Arthroplasty and Anterior Cervical Discectomy With Fusion

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To determine risks of reoperations for adjacent segment disease (ASD) and all-cause reoperations following cervical disc arthroplasty (CDA) versus anterior cervical discectomy with fusion (ACDF). SUMMARY OF BACKGROUND DATA: To reduce the risk of ASD, CDA was developed to preserve mobility. While studies show CDA lowers ASD reoperation rates, few have included all-cause reoperation risks. METHODS: Using data from a National Spine Registry, patients (18-60 yr old) with cervical degenerative disc disease who underwent a primary one-level and two-level CDA or ACDF were selected. Patients with ACDF were 3:1 propensity-score matched to CDA patients. Cox Proportional-Hazards regression was used to evaluate reoperations for ASD and all-cause risks. Hazard ratios (HR) and 95% CIs were presented; P < 0.05 was the significance threshold. RESULTS: The cohort consisted of 6318 patients with a mean follow-up of 6.9 years. Propensity score matching yielded 809 CDA patients and 2427 ACDF patients. In Cox Regression analysis, a lower risk of reoperation for ASD was observed for 1-level CDA compared with ACDF (HR=0.86, 95% CI=0.64-1.15, P = 0.31) but without statically significance. For one-level and two-level, no difference in all-cause reoperation risks was found (HR=0.84, 95% CI=0.64-1.12, P = 0.25) and (HR=0.67, 95% CI=0.33-1.37, P = 0.27), respectively. Mean time to ASD reoperation was 3.9 years (SD=3.5) for CDA and 4.4 years (SD=3.1) for ACDF. CONCLUSION: With nearly seven years of average follow-up, this large registry-based study showed that one-level CDA did not significantly reduce the risk of ASD or all-cause reoperations compared with ACDF. Similar results were only seen for all-cause reoperations in two-level CDA. Importantly, ASD reoperations occurred within four to five years on average, underscoring that while CDA preserves motion, the risk of subsequent surgery remains. These findings highlight the real-world performance of CDA and may reflect other factors that increase all-cause reoperations, which may have been underreported.