title: Posterior Reduction of Fixed Atlantoaxial Dislocation and Basilar Invagination by Atlantoaxial Facet Joint Release and Fixation: A Modified Technique With 174 Cases.
abstract: BACKGROUND
  Treatment of fixed atlantoaxial dislocation (AAD) with basilar invagination (BI) is challenging.
  
  
  OBJECTIVE
  To introduce a modified technique to reduce fixed AAD and BI through a posterior approach.
  
  
  METHODS
  From 2007 to 2013, 174 patients with fixed AAD and BI underwent surgical reduction by posterior atlantoaxial facet joint release and fixation technique.
  
  
  RESULTS
  There was 1 death in the series, and 3 patients were lost to follow-up. The follow-up period ranged from 12 to 52 months (mean: 35.2 months) for the remaining 170 patients. Neurological improvement was observed in 168 of 170 patients (98.8%), and was stable in 1 (0.06%) and exacerbated in 1 (0.06%), with the Japanese Orthopedic Association scores increasing from 11.4 preoperatively to 15.8 postoperatively (P < .01). Radiologically, complete or >90% reduction was attained in 107 patients (62.9%), 60% to 90% reduction was attained in 51 patients (30%), and <50% reduction was attained in 12 patients (7.1%), who underwent additional transoral decompression. Complete decompression was demonstrated in all 170 patients. Solid bony fusion was demonstrated in 167 patients at follow-up (98.2%).
  
  
  CONCLUSIONS
  This series showed the safety and efficacy of the posterior C1-2 facet joint release and reduction technique for the treatment of AAD and BI. Most fixed AAD and BI cases are reducible via this method. In most cases, this method avoids transoral odontoidectomy and cervical traction. Compared with the occiput-C2 screw method, this short-segment C1-2 technique exerts less antireduction shearing force, guarantees longer bone purchase, and provides more immediate stabilization.
authors.affiliation: Department of Neurosurgery, PLA (People's Liberation Army) General Hospital, Beijing, China.
authors.forename: Yi-heng
authors.initials: YH
authors.lastname: Yin
authors.forename: Huai-yu
authors.initials: HY
authors.lastname: Tong
authors.forename: Guang-yu
authors.initials: GY
authors.lastname: Qiao
authors.forename: Xin-guang
authors.initials: XG
authors.lastname: Yu
mesh_terms: D000328:Adult; D000368:Aged; D001268:Atlanto-Axial Joint / Q000473:pathology / Q000601:surgery*; D001863:Bone Screws; D001933:Brain Stem / Q000473:pathology; D019299:Decompression, Surgical / Q000379:methods; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000379:methods*; D011184:Postoperative Period; D020127:Recovery of Function