title: Comparison of isocentric C-arm 3-dimensional navigation and conventional fluoroscopy for C1 lateral mass and C2 pedicle screw placement for atlantoaxial instability.
abstract: METHODS
  A retrospective study.
  
  
  OBJECTIVE
  The aim of the study was to compare the precision of C1 lateral mass and C2 pedicle (C1LM-C2P) screw fixation for atlantoaxial instability using the isocentric C-arm 3-dimensional (Iso-C 3D) navigation versus conventional fluoroscopy.
  
  
  BACKGROUND
  The Iso-C 3D navigation has been widely used in spinal surgeries in recent years. The advantages of this navigation system compared with conventional fluoroscopy in C1LM-C2P screw fixation for atlantoaxial instability are not known.
  
  
  METHODS
  Twenty-four patients diagnosed with atlantoaxial instability were treated with C1LM-C2P screw fixation in this study. The navigation group included 12 patients and the other 12 patients were in the conventional fluoroscopy group. The clinical and radiographic results were recorded and compared between the 2 groups. Patients were followed up with clinical examination and radiographs at a mean of 10.8 months.
  
  
  RESULTS
  There were no significant differences between groups in the mean age, gender, and causes of atlantoaxial instability. Operative time was 130 ± 5.4 minutes in the navigation group versus 145 ± 6.5 minutes in the conventional fluoroscopy group. The mean blood loss in the navigation group was 304.2 ± 47.9 mL relative to 462.5 ± 55.4 mL in the conventional fluoroscopy group. The radiation time was significantly reduced using 3D navigation (47.5 ± 1.5 s vs. 64.0 ± 3.0 s). 95.8% (46/48) of 3D navigated screws and 83.3% (40/48) of fluoroscopy screws had no pedicle perforation. Each patient showed evidence of solid fusion after 6 months on cervical plain radiographies.
  
  
  CONCLUSIONS
  On comparing the 2 imaging techniques, it was found that using Iso-C 3D navigation can significantly improve the accuracy of screw placement and decrease intraoperative fluoroscopic time and blood loss. This study demonstrates that Iso-C 3D navigation is a safe and effective means of guiding C1LM-C2P screw fixation for atlantoaxial instability.
authors: Department of Orthopaedics, Shandong Provincial Hospital Affiliated to Shandong University, Jinan, China.
authors: Yong Liang
authors: YL
authors: Yang
authors: Dong Sheng
authors: DS
authors: Zhou
authors: Ji Liang
authors: JL
authors: He
mesh_terms: D000328:Adult; D001268:Atlanto-Axial Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D001863:Bone Screws; D005260:Female; D005471:Fluoroscopy / Q000379:methods*; D006801:Humans; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013123:Spinal Fusion / Q000379:methods*; D025321:Surgery, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome