title: Posterior fixation and fusion of unstable Hangman's fracture by using intraoperative three-dimensional fluoroscopy-based navigation.
abstract: OBJECTIVE
  The purpose of this study was to assess the efficacy and accuracy of posterior screw fixation for unstable Hangman's fracture using intraoperative 3D fluoroscopy-based navigation.
  
  
  METHODS
  14 patients with unstable Hangman's fractures (11 males and 3 females), ranging in age from 21 to 59 years, received posterior fixation assisted by an intraoperative 3D fluoroscopy-based navigation system: 11 Levine-Edwards type II and three type IIA cases. The American Spine Injury Association grade was D in 2 and E in 12 cases.
  
  
  RESULTS
  Operation time was 110 min (range 90-140 min). Hospital stay was 7.6 days (range 5-12 days). All the patients were observed for an average of 28.8 months (range 15-50 months). No screw-related injury to nerve, or vertebral artery was observed intraoperatively. An average of four screws/patient were inserted. Pedicle screws were placed into C2 and C3, and 5 screws were into the lateral mass of C3. Screw placement accuracy was evaluated using postoperative CT, according to the modified classification of Gertzbein and Robbins; one screw was grade 2 in C2, and three screws were grade 2 in the pedicle of C3. No grade 3 misplacement or clinical deficits were noted. C3 lateral mass screws were successfully inserted. Neck pain was relieved in each case. Neurologic status improved from D to E in 2 cases. Solid fusion was demonstrated in all the cases by static and dynamic films during the final follow-up.
  
  
  CONCLUSIONS
  This case series demonstrates that intraoperative 3D fluoroscopy-based navigation is a safe, accurate, and effective tool for screw placement in patients with unstable Hangman's fracture.
authors: Department of Spine Surgery, Peking University Fourth Clinical Medical College, Beijing Jishuitan Hospital, NO. 31, Xinjiekou East Street, Xicheng District, Beijing, People's Republic of China. orthdanielcw@yahoo.com
authors: Wei
authors: W
authors: Tian
authors: Chong
authors: C
authors: Weng
authors: Bo
authors: B
authors: Liu
authors: Qin
authors: Q
authors: Li
authors: Lin
authors: L
authors: Hu
authors: Zhi-Yu
authors: ZY
authors: Li
authors: Ya-Jun
authors: YJ
authors: Liu
authors: Yu-Zhen
authors: YZ
authors: Sun
mesh_terms: D000328:Adult; D001368:Axis, Cervical Vertebra / Q000000981:diagnostic imaging / Q000293:injuries* / Q000601:surgery; D001863:Bone Screws; D005260:Female; D005471:Fluoroscopy / Q000379:methods*; D005593:Fracture Fixation, Internal / Q000295:instrumentation / Q000379:methods*; D050723:Fractures, Bone / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D016268:Internal Fixators; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000379:methods; D012189:Retrospective Studies; D013123:Spinal Fusion / Q000295:instrumentation / Q000379:methods*; D013168:Spondylolisthesis / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome