title: Addressing the challenges and controversies of managing os odontoideum: results of a systematic review.
abstract: BACKGROUND
  Os odontoideum is a rare condition with a controversial pathogenesis and poorly understood natural history. As a result, it is difficult for clinicians to predict which patients require surgical fusion to prevent symptomatic progression and potentially devastating neurologic injury.
  
  
  METHODS
  We undertook a systematic review of the literature to evaluate the clinical outcomes in the treatment of asymptomatic and symptomatic cases of os odontoideum. Pubmed, EMBASE, Cochrane, National Guideline Clearinghouse Databases as well as bibliographies of key articles were searched. Articles were reviewed by two independently working reviewers. Inclusion and exclusion criteria were set and each article was subject to a predefined quality rating scheme.
  
  
  RESULTS
  We identified eleven articles meeting our inclusion criteria. Seven studies included patients with asymptomatic os odontoideum discovered incidentally from which it was possible to examine data on 18 individuals. Six studies were identified containing more than 15 patients with symptomatic os odontoideum.
  
  
  CONCLUSIONS
  The existing literature regarding both asymptomatic or symptomatic os odontoideum and its treatment is very limited. No definitive conclusions can be drawn from these studies. A basic approach to the management of os odontoideum is offered based on the findings of this study.
authors.affiliation: Division of Neurosurgery, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Jefferson R
authors.initials: JR
authors.lastname: Wilson
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Dettori
authors.forename: Ellen M
authors.initials: EM
authors.lastname: Vanalstyne
authors.forename: Michael G
authors.initials: MG
authors.lastname: Fehlings
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