title: Accuracy of pedicle screw insertion using fluoroscopy-based navigation-assisted surgery : computed tomography postoperative assessment in 96 consecutive patients.
abstract: OBJECTIVE
  Two-dimensional fluoroscopy-based computerized navigation for the placement of pedicle screws offers the advantage of using stored patient-specific imaging data in providing real-time guidance during screw placement. The study aimed to describe the accuracy and reliability of a fluoroscopy-based navigation system for pedicle screw insertion.
  
  
  METHODS
  A total of 477 pedicle screws were inserted in the lower back of 96 consecutive patients between October 2007 and June 2012 using fluoroscopy-based computer-assisted surgery. The accuracy of screw placement was evaluated using a sophisticated computed tomography protocol.
  
  
  RESULTS
  Of the 477 pedicle screws, 461 (96.7%) were judged to be inserted correctly. Frank screw misplacement [16 screws (3.3%)] was observed in 15 patients. Of these, 8 were classified as minimally misplaced (≤2 mm); 3, as moderately misplaced (2.1-4 mm); and 5, as severely misplaced (>4 mm). No complications, including nerve root injury, cerebrospinal fluid leakage, or internal organ injury, were observed in any of the patients.
  
  
  CONCLUSIONS
  The accuracy of pedicle screw placement using a fluoroscopy-based computer navigation system was observed to be superior to that obtained with conventional techniques.
authors.affiliation: Department of Neurosurgery, Ulsan University Hospital, Ulsan, Korea.
authors.forename: Keong Duk
authors.initials: KD
authors.lastname: Lee
authors.affiliation: Department of Neurosurgery, Ulsan University Hospital, Ulsan, Korea.
authors.forename: In Uk
authors.initials: IU
authors.lastname: Lyo
authors.affiliation: Department of Radiology, Ulsan University Hospital, Ulsan, Korea.
authors.forename: Byeong Seong
authors.initials: BS
authors.lastname: Kang
authors.affiliation: Department of Neurosurgery, Ulsan University Hospital, Ulsan, Korea.
authors.forename: Hong Bo
authors.initials: HB
authors.lastname: Sim
authors.affiliation: Department of Neurosurgery, Ulsan University Hospital, Ulsan, Korea.
authors.forename: Soon Chan
authors.initials: SC
authors.lastname: Kwon
authors.affiliation: Department of Neurosurgery, Ulsan University Hospital, Ulsan, Korea.
authors.forename: Eun Suk
authors.initials: ES
authors.lastname: Park
keywords: Accuracy; Fluoroscopy-based navigator; Pedicle screw