title: A systematic review of randomized trials on the effect of cervical disc arthroplasty on reducing adjacent-level degeneration.
abstract: OBJECTIVE
  Anterior cervical discectomy and fusion had been considered a safe and effective procedure for radiculopathy and myelopathy in the cervical spine, but degeneration in adjacent spinal levels has been a problem in some patients after fusion. Since 2002, cervical disc arthroplasty has been established as an alternative to fusion. The objective of this study was to review data concerning the role of cervical arthroplasty in reducing adjacent-level degeneration.
  
  
  METHODS
  A systematic review was performed using the MEDLINE, EMBASE, Cochrane, and LILACS databases, focusing on a structured question involving the population of interest, types of intervention, types of control, and outcomes studied.
  
  
  RESULTS
  No study has specifically compared the results of arthroplasty with the results of fusion with respect to the rate of postoperative development of adjacent-segment degenerative disease. One paper described a rate for adjacent-level surgery. The level of evidence of that paper was classified 2b, and although its authors found a statistically significant between-groups difference (arthroplasty vs fusion) using log-rank analysis, re-analysis according to number needed to treat (in the current paper) did not reveal statistical significance.
  
  
  CONCLUSIONS
  Adjacent-level degeneration has not been adequately studied in a review of the available randomized controlled trials on this topic, and there is no clinical evidence of reduction in adjacent-level degeneration with the use of cervical arthroplasty.
authors.affiliation: Neurosurgical Service, Hospital do Servidor Público do Estado de São Paulo, São Paulo, Brazil. bitbot@uol.com.br
authors.forename: Ricardo Vieira
authors.initials: RV
authors.lastname: Botelho
authors.forename: Osmar José dos Santos
authors.initials: OJ
authors.lastname: Moraes
authors.forename: Gustavo Alberto
authors.initials: GA
authors.lastname: Fernandes
authors.forename: Yuri dos Santos
authors.initials: Ydos S
authors.lastname: Buscariolli
authors.forename: Wanderley Marques
authors.initials: WM
authors.lastname: Bernardo
mesh_terms: D001178:Arthroplasty / Q000009:adverse effects / Q000379:methods* / Q000706:statistics & numerical data; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery; D018450:Disease Progression; D017586:Diskectomy / Q000009:adverse effects / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D011183:Postoperative Complications / Q000453:epidemiology* / Q000503:physiopathology / Q000517:prevention & control; D011859:Radiography; D016032:Randomized Controlled Trials as Topic; D055502:Secondary Prevention; D013123:Spinal Fusion / Q000009:adverse effects / Q000379:methods* / Q000706:statistics & numerical data; D055009:Spondylosis / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*