165. Risk of revision surgery following cervical disc replacement vs anterior cervical discectomy and fusion: population based cohort study.

In recent years, cervical disc replacement (CDR) has gained popularity for cervical degenerative disorders. The rationale for CDR over anterior cervical discectomy and fusion (ACDF) is preservation of segmental motion and physiological spinal kinematics, which is hoped to delay development of adjacent segment disease and reoperation rates. Superiority of CDR over ACDF in rates of secondary surgeries has not been demonstrated in long-term follow-up. This study compares rate of reoperation in CDR and ACDF for treatment of cervical degenerative disc disease using population-based data for the province of Ontario. A population-based cohort study was conducted using health administrative databases including patients undergoing ACDF or CDR between October 2005 to March 2018. Patients receiving CDR vs ACDF were identified using physician service claims and hospital discharge abstracts. The primary outcome was revision surgery in the cervical spine defined as an operation more than 30 days after the index procedure. Secondary outcomes were immediate/acute complications within the first 30 days after the index operation, readmissions and length of hospital stay. METHODS: Cox proportional hazard models were used to identify predictors of time to revision surgery. Predictors of the binary outcome of an immediate complication within 30 days were estimated using logistic regression. A total of 5,207 patients were included. Mean follow-up was 2,728 days for CDR and 2,542 days for ACDF. Among 4,937 ACDF procedures, 7.5% underwent subsequent revision surgery and among 270 CDR procedures, 8.9% had revision surgery. While the study groups did not differ in their risk of revision surgery (adjusted HR 1.20, 95% CI 0.78-1.85), CDR was associated with a lower probability of an acute complication (adjusted OR 0.41, 95% CI 0.21-0.80). Among other factors, multi-level surgery was an independent predictor of acute complication [OR= 1.33 (95% CI 1.06 – 1.66)]. CDR patients experienced shorter mean (±SD) length of hospital stay [1.42 (±0.87) vs. 2.00 ± (3.08) d for ACDF]. This study does not demonstrate superiority of CDR over ACDF in revision surgery at the index and/or adjacent level of the cervical spine for single and multi-level procedures. CDR may have an advantage over ACDF in the acute postoperative phase, with a shorter length of hospital stay and lower probability of acute complication. This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]