title: Atlantoaxial fusion with transarticular screws: meta-analysis and review of the literature.
abstract: OBJECTIVE
  To review published series describing C1-2 posterior instrumented fusions and summarize clinical and radiographic outcomes of patients treated with transarticular screw (TAS) fixation.
  
  
  METHODS
  Online databases were searched for English-language articles published between 1986 and April 2011 describing posterior atlantoaxial instrumentation with C1-2 TAS fixation. There were 45 studies including 2073 patients treated with TAS that fulfilled inclusion criteria. Meta-analysis techniques were used to calculate outcomes.
  
  
  RESULTS
  All studies provided class III evidence. The 30-day perioperative mortality rate was 0.8%, and the incidence of neurologic injury was 0.2%. The incidence of clinically significant malpositioned screws was 7.1% (confidence interval [CI], 5.7%-8.8%), the incidence of vertebral artery injury was 3.1% (CI, 2.3%-4.3%), and the rate of fusion with the TAS technique was 94.6% (CI, 92.6%-96.1%).
  
  
  CONCLUSIONS
  TAS fixation is a safe and effective treatment option for C1-2 instability with high rates of fusion (approximately 95%). Screw malposition and vertebral artery injury occurred in approximately 5% of patients. The successful insertion of TAS requires a thorough knowledge of atlantoaxial anatomy.
authors.affiliation: Neurosurgical Care, LLC, Royersford, Pennsylvania, USA. Electronic address: robertelliottmd@gmail.com.
authors.forename: Robert E
authors.initials: RE
authors.lastname: Elliott
authors.forename: Omar
authors.initials: O
authors.lastname: Tanweer
authors.forename: Akwasi
authors.initials: A
authors.lastname: Boah
authors.forename: Amr
authors.initials: A
authors.lastname: Morsi
authors.forename: Tracy
authors.initials: T
authors.lastname: Ma
authors.forename: Anthony
authors.initials: A
authors.lastname: Frempong-Boadu
authors.forename: Michael L
authors.initials: ML
authors.lastname: Smith
mesh_terms: D001268:Atlanto-Axial Joint / Q000601:surgery*; D001863:Bone Screws; D006801:Humans; D007593:Joint Instability / Q000401:mortality / Q000601:surgery*; D013123:Spinal Fusion / Q000295:instrumentation* / Q000379:methods* / Q000401:mortality; D014711:Vertebral Artery / Q000601:surgery