Complications and Risk Factors Using Structural Allograft Versus Synthetic Cage: Analysis 17 783 Anterior Cervical Discectomy and Fusions Using a National Registry

Study Design: Retrospective cohort study. Objective: To determine the rates of perioperative complications in patients undergoing anterior cervical discectomy and fusion (ACDF) with allograft versus synthetic cage. Methods: A large national administrative health care database was queried for ACDF procedures performed between 2007 and 2014 using ICD-9 (International Statistical Classification of Diseases, 9th revision) and CPT (Current Procedural Terminology) codes. Cases that utilized structural allograft and synthetic cages were identified via CPT codes. Gender, age, frequency of obesity, cigarette use, diabetes, and number of levels fused were compared between the 2 cohorts using chi(2) test. Complications within 90 days were identified via ICD-9 codes and compared between the 2 cohorts. Revision rates within 2 years were noted. Results: A total of 10 648 ACDF cases using synthetic cages and 7135 ACDFs using structural allograft were identified. The demographics between the 2 cohorts were similar. Overall complication rate was 8.71% in the synthetic cage group compared with 7.76% in the structural allograft group (P < .01). Use of synthetic cage was associated with higher rate of respiratory complications, 0.57% compared with 0.31% in the structural allograft cohort (P = .03), while use of structural allograft was associated with a higher rate of dysphagia, 0.64% compared with 0.33% (P < .01). Revision rate at 2 years was 0.50% and 0.56% in the synthetic cage and allograft groups, respectively (P = .03). Conclusions: This data suggests that synthetic cages are associated with a marginally higher overall rate of complications with similar revision rates.