title: Odontoid screw placement using Isocentric 3-dimensional C-arm fluoroscopy.
abstract: METHODS
  We describe the use of isocentric 3-dimensional fluoroscopy to place odontoid screws in 9 patients.
  
  
  OBJECTIVE
  We wanted to show the benefits of using isocentric 3-dimensional fluroscopy in odontoid screw placement.
  
  
  BACKGROUND
  Odontoid screw fixation for treatment of type II odontoid fractures has gained popularity since its introduction in the early 1980s. During the last several years, a multitude of new techniques have improved the ease of odontoid screw placement, including biplanar fluoroscopy, cannulated screw systems, and beveled bedside-fixed retractor systems. The use of isocentric C-arm fluoroscopy can improve the ease and facilitate placement of odontoid screws.
  
  
  METHODS
  Nine patients, ranging in ages from 30 to 89 years, presented with type II odontoid fractures. All fractures were either nondisplaced or minimally displaced (<4 mm) and occurred as a result of acute trauma. No patient had evidence of transverse atlantal ligament disruption.
  
  
  METHODS
  Isocentric 3-dimensional fluoroscopy, in conjunction with image-guided navigational software, was used to place 1 or 2 odontoid screws in each patient. Three-dimensional images were acquired intraoperatively, which were then reconstructed and uploaded to the navigational workstation. Screw trajectory was planned and performed with the use of tracked instruments.
  
  
  RESULTS
  Successful screw placement, as judged by intraoperative computerized tomography, was attained in all 9 patients.
  
  
  CONCLUSIONS
  Isocentric 3-dimensional fluoroscopy, in conjunction with an image-guided navigational software system, obviates the need for cumbersome biplanar fluoroscopy, allows for intraoperative image acquisition after surgical exposure, reduces intraoperative registration time, reduces both surgeon and patient radiation exposure, and allows immediate computerized tomographic imaging in the operating room to verify screw position.
authors.affiliation: Department of Neurological Surgery, McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA.
authors.forename: Lori E
authors.initials: LE
authors.lastname: Summers
authors.forename: Joshua G
authors.initials: JG
authors.lastname: Kouri
authors.forename: Mu
authors.initials: M
authors.lastname: Yang
authors.forename: R
authors.initials: R
authors.lastname: Patrick Jacob
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001863:Bone Screws / Q000592:standards*; D005260:Female; D005471:Fluoroscopy / Q000295:instrumentation / Q000379:methods; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D016268:Internal Fixators / Q000592:standards; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation / Q000379:methods*; D009809:Odontoid Process / Q000000981:diagnostic imaging / Q000293:injuries / Q000601:surgery*; D016103:Spinal Fractures / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D013123:Spinal Fusion / Q000295:instrumentation* / Q000379:methods*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome