title: Fluoroscopic computer-assisted pedicle screw placement through a mature fusion mass: an assessment of 24 consecutive cases with independent analysis of computed tomography and clinical data.
abstract: METHODS
  Observational matched cohort study with computed tomography (CT) analysis of pedicle screw placement.
  
  
  OBJECTIVE
  Assess the clinical accuracy of computer-assisted fluoroscopy for the placement of thoracolumbar pedicle screws through a mature posterolateral fusion mass.
  
  
  BACKGROUND
  Pedicle screw placement through an amorphous posterolateral fusion mass intuitively carries a higher risk of pedicle wall violation.
  
  
  METHODS
  Postoperative CT scans of 102 pedicle screws placed through a mature posterolateral fusion mass (n = 10 [T10-T12]; n = 92 [L1-S1]) were independently assessed and compared with a matched control (nonobscured anatomy) group. All screws were placed before any decompression using the FluoroNav system.
  
  
  RESULTS
  In the fusion mass group, overall 81.4% of screws were completely within the pedicle. Seven medial and 12 lateral pedicle breaches occurred. Relative to the total number of screws, pedicle breaches were graded II (<2 mm) in 13.5%, III (2-4 mm) in 2.9%, and IV (>4 mm) in 2.0% of screws. The number and direction of pedicle breaches were not significantly different when compared with the control group. There were no clinically significant screw misplacements in either group.
  
  
  CONCLUSIONS
  The use of computer-assisted fluoroscopy is safe and effective for the placement of thoracolumbar (T10-S1) pedicle screws through a posterolateral fusion mass without performing laminoforaminotomies.
authors.affiliation: Division of Orthopaedic, University of Toronto, Toronto, Ontario, Canada. raja.rampersaud@uhn.on.ca
authors.forename: Yoga Raja
authors.initials: YR
authors.lastname: Rampersaud
authors.forename: Kwang-Soo
authors.initials: KS
authors.lastname: Lee
mesh_terms: D000328:Adult; D000368:Aged; D001863:Bone Screws / Q000009:adverse effects; D015331:Cohort Studies; D005260:Female; D005471:Fluoroscopy; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011184:Postoperative Period; D012086:Reoperation; D013123:Spinal Fusion; D025321:Surgery, Computer-Assisted; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome