Background: Anterior cervical discectomy and fusion (ACDF), is commonly used for treatment of degenerative cervical spondylotic radiculopathy and myelopathy, and satisfactory out-comes have been reported in many studies. However, subsequent disc degeneration at levels adjacent to the fusion remains an important problem.
Aim of the Work: To perform a systematic review and meta-analysis to evaluate incidence, risk factors, and impact of radiographic and clinical postoperative adjacent segment degeneration (ASD) following anterior decompression and instrumented fusion.
Method: Medline databases (PubMed, Medscape, Science Direct. EMF-Portal) and all materials available in the Internet till 2020.
Data Extraction: If the studies did not fulfill the inclusion criteria, they were excluded. Study quality assessment included whether ethical approval was gained, eligibility criteria specified, appropriate controls, and adequate information and defined assessment measures.
Conclusion: 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.