title: Independent assessment of a new pedicle probe and its ability to detect pedicle breach: a cadaveric study.
abstract: OBJECTIVE
  The authors undertook an independent, non-industry funded cadaveric study to evaluate the efficacy of a pedicle-probing device, which uses impedance measurement to warn of impending and actual pedicle screw breach.
  
  
  METHODS
  A previously validated fresh-frozen cadaver model (saline-soaked spine) was used. Individuals at 3 levels of training (attending spine surgeon, orthopedic surgery resident, and medical student) used a cannulated pedicle-probing device to cannulate each of the levels between T-2 and S-1. Each pedicle was cannulated freehand using 2 approaches: 1) a standard trajectory through the middle of the pedicle, and 2) a medial trajectory aimed to breach the medial wall of the pedicle. A 16-slice helical CT scanner was used. The images were interpreted and analyzed by 2 orthopedic spine surgeons and a neuroradiologist.
  
  
  RESULTS
  The sensitivity of the pedicle probe to detect impending breach or breach of 4 mm or less was 90.06%. The sensitivity in detecting medial wall breach was 95.8%. The positive predictive value was 87.1%. The device detected medial breach more often than lateral breach.
  
  
  CONCLUSIONS
  This study showed that this pedicle-probing device could reasonably be used to detect impending breach and actual breach of 4 mm or less. Medial breach was detected better than lateral breach. Use of the pedicle probe may improve patient safety.
authors.affiliation: Departments of 1 Orthopaedic Surgery and.
authors.forename: Phillip T
authors.initials: PT
authors.lastname: Guillen
authors.forename: Ryan G
authors.initials: RG
authors.lastname: Knopper
authors.forename: Jared
authors.initials: J
authors.lastname: Kroger
authors.forename: Nathaniel D
authors.initials: ND
authors.lastname: Wycliffe
authors.forename: Olumide A
authors.initials: OA
authors.lastname: Danisa
authors.forename: Wayne K
authors.initials: WK
authors.lastname: Cheng
mesh_terms: D002102:Cadaver; D006801:Humans; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery; D016343:Monitoring, Intraoperative / Q000295:instrumentation*; D019635:Neurosurgical Procedures; D065289:Pedicle Screws / Q000009:adverse effects*; D012447:Sacrum / Q000000981:diagnostic imaging / Q000601:surgery; D012680:Sensitivity and Specificity; D013131:Spine / Q000000981:diagnostic imaging / Q000601:surgery*; D013904:Thoracic Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery; D036542:Tomography, Spiral Computed
keywords: PPV = positive predictive value; PediGuard; cadaveric study; pedicle breach; pedicle screw; technique