title: Accuracy and safety of pedicle screw fixation in thoracic spine trauma.
abstract: OBJECTIVE
  The authors evaluated the accuracy of placement and safety of pedicle screws in the treatment of unstable thoracic spine fractures.
  
  
  METHODS
  Patients with unstable fractures between T-1 and T-10, which had been treated with pedicle screw (PS) placement by one of five spine surgeons at a referral center were included in a prospective cohort study. Postoperative computed tomography scans were obtained using 3-mm axial cuts with sagittal reconstructions. Three independent reviewers (C.B., V.S., and D.G.) assessed PS position using a validated grading scale. Comparison of failure rates among cases grouped by selected baseline variables were performed using Pearson chi-square tests. Independent peri- and postoperative surveillance for local and general complications was performed to assess safety. Twenty-three patients with unstable thoracic fractures treated with 201 thoracic PSs were analyzed. Only PSs located between T-1 and T-12 were studied, with the majority of screws placed between T-5 and T-10. Of the 201 thoracic PSs, 133 (66.2%) were fully contained within the pedicle wall. The remaining 68 screws (33.8%) violated the pedicle wall. Of these, 36 (52.9%) were lateral, 27 (39.7%) were medial, and five (7.4%) were anterior perforations. No superior, inferior, anteromedial, or anterolateral perforations were found. When local anatomy and the clinical safety of screws were considered, 98.5% (198 of 201) of the screws were probably in an acceptable position. No baseline variables influenced the incidence of perforations. There were no adverse neurological, vascular, or visceral injuries detected intraoperatively or postoperatively.
  
  
  CONCLUSIONS
  In the vast majority of cases, PSs can be placed in an acceptable and safe position by fellowship-trained spine surgeons when treating unstable thoracic spine fractures. However, an unacceptable screw position can occur.
authors.affiliation: Department of Orthopaedics, Spine Division, University of British Columbia, Canada. charles.fisher@vch.ca
authors.forename: Charles G
authors.initials: CG
authors.lastname: Fisher
authors.forename: Vic
authors.initials: V
authors.lastname: Sahajpal
authors.forename: Ory
authors.initials: O
authors.lastname: Keynan
authors.forename: Michael
authors.initials: M
authors.lastname: Boyd
authors.forename: Douglas
authors.initials: D
authors.lastname: Graeb
authors.forename: Christopher
authors.initials: C
authors.lastname: Bailey
authors.forename: Kostas
authors.initials: K
authors.lastname: Panagiotopoulos
authors.forename: Marcel F
authors.initials: MF
authors.lastname: Dvorak
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001863:Bone Screws / Q000009:adverse effects; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D011446:Prospective Studies; D016103:Spinal Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D013123:Spinal Fusion / Q000295:instrumentation / Q000379:methods*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000293:injuries* / Q000601:surgery*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome