Comparative Outcomes in Cervical Spine Surgery: A Dual Analysis of Revision Surgeries and Adjacent Segment Degeneration

Abstract

Background Cervical disc arthroplasty (CDA) is increasingly favored over anterior cervical discectomy and fusion (ACDF) for its motion-preserving capabilities and theoretical advantage in reducing adjacent segment degeneration (ASD). While evidence on revision surgery rates between CDA and ACDF remains inconsistent, the performance of individual CDA implants concerning ASD and related complications has received less comparative scrutiny. This study aimed to (1) compare the hazard and predictors of revision surgery between ACDF and CDA, and (2) evaluate the risk of ASD and complications across three commonly used CDA implants: Prodisc-C, Mobi-C, and M6-C. Methods We conducted a two-part retrospective cohort study at a single academic medical center. First, using propensity-score matching (2:1), 312 patients who underwent ACDF or CDA between January 2008 and June 2023 were analyzed to compare revision surgery rates and identify associated risk factors. Second, 70 CDA cases (17 M6-C, 21 Prodisc-C, 32 Mobi-C) performed by a single surgeon between 2008 and 2024 were reviewed for ASD development and implant-specific complications. Multivariable Cox regression was used to assess hazard ratios (HR) for revision surgery and ASD, adjusting for demographics, comorbidities, and operative characteristics. Results CDA was associated with a significantly lower hazard of revision surgery compared to ACDF (HR 0.36; 95% CI 0.017–0.77; p=0.01). Age, gender, diabetes, hypertension, heart disease, chronic steroid use, and opioid dependence were not significant predictors of revision risk. Two-level surgeries were not associated with increased revision hazard relative to one-level procedures (HR 0.78; 95% CI 0.48–1.53; p=0.48). Among CDA implants, the risk of developing ASD was not significantly different for M6-C (HR 1.94; 95% CI 0.19–20.14; p=0.58) or Mobi-C (HR 1.69; 95% CI 0.26–10.77; p=0.58) when compared to Prodisc-C. No demographic, lifestyle, or operative variables were associated with ASD risk, and no implant-specific complications showed statistically significant differences across implant types. Conclusion CDA is associated with a lower risk of revision surgery relative to ACDF, with no significant predictors identified among common clinical variables. Among CDA implants, Prodisc-C, Mobi-C, and M6-C demonstrated similar performance in terms of ASD risk and implant-related complications. These findings support the long-term durability of CDA over ACDF and suggest comparable outcomes across commonly used CDA implant designs.