title: Adjacent segment degenerative disease: is it due to disease progression or a fusion-associated phenomenon? Comparison between segments adjacent to the fused and non-fused segments.
abstract: BACKGROUND
  The purpose of this study was to determine whether fusion causes adjacent segment degeneration or whether degeneration is due to disease progression.
  
  
  METHODS
  Eighty-seven patients that had undergone single level anterior cervical decompression and fusions with at least 5 years of follow-up were enrolled in this retrospective study. Segments adjacent to fusion levels (above or below) were allocated to group A, and all others were allocated to group B. Radiographic evaluations of adjacent level changes included assessments of; disc degenerative changes, anterior ossification formation, and segmental instability. The developments of new clinical symptoms were also evaluated.
  
  
  RESULTS
  In group A, adjacent segment degenerative change developed in 28 segments (16%) and two cases (2%) developed new clinical symptoms. In group B, adjacent segment degenerative change developed in 10 segments (3%), and two cases (0.7%) also developed new clinical symptoms. Additional operations were performed in one patient in each group.
  
  
  CONCLUSIONS
  Although, fusion per se can accelerate the severity of adjacent level degeneration, no significant difference was observed between adjacent and non-adjacent segments in terms of the incidence of symptomatic disease. The authors conclude that adjacent segment disease is more a result of the natural history of cervical spondylosis than the presence of fusion.
authors.affiliation: Department of Orthopedic Surgery, School of Medicine, Research Institute of Clinical Medicine, Chonbuk National University Hospital, Jeonju, Korea.
authors.forename: Kyung-Jin
authors.initials: KJ
authors.lastname: Song
authors.forename: Byung-Wan
authors.initials: BW
authors.lastname: Choi
authors.forename: Taek-Soo
authors.initials: TS
authors.lastname: Jeon
authors.forename: Kwang-Bok
authors.initials: KB
authors.lastname: Lee
authors.forename: Han
authors.initials: H
authors.lastname: Chang
mesh_terms: D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging* / Q000601:surgery; D019299:Decompression, Surgical; D018450:Disease Progression; D017586:Diskectomy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D013123:Spinal Fusion; D055009:Spondylosis / Q000000981:diagnostic imaging* / Q000601:surgery