Adjacent Segment Degeneration after Anterior Cervical Discectomy and Fusion

Abstract

Despite the high rate of success with ACDF, long term follow-up has identified ASDeg and ASDz as possible post-operative sequelae that may require reoperation. The coredebate concerns whether these conditions represent the natural attritive process of aging or are instead a result of the biomechanical changes induced by surgical fusion. If the former is true, index ACDF procedures may be adjusted to include additional levels now identified as higher risk. If the latter is true, motion preserving treatments such as CDR may gain more traction. This review illuminates the heterogeneous methodology of the literature on ASDeg and ASDz after ACDF and the paucity of high-quality data published on these phenomena. Standardized methodology for radiographic evaluation of ASDeg and clinical outcome measures for ASDz are critical before the fundamental question on their etiology can be resolved.