Probing for thoracic pedicle screw tract violation(s): Is it valid?

Ronald A. Lehman, Benjamin K. Potter, Timothy R. Kuklo*, Audrey S. Chang, David W. Polly, Scott B. Shawen, Joseph R. Orchowski

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


Background: Preparation of the thoracic pedicle screw tract is a critical step prior to the placement of screws. The ability to detect pedicle wall violation(s) by probing prior to insertion of thoracic pedicles screws, however, has not been studied. The purpose of this study was to evaluate the inter- and intraobserver agreement and the accuracy in detecting thoracic pedicle screw tract violation(s) among surgeons at various levels of training. Methods: With use of a straightforward trajectory, under direct visualization, 108 thoracic pedicle screw tracts (54 cadaveric thoracic vertebrae) were prepared in a standard fashion, followed by tapping with a 4.5-mm cannulated tap. A deliberate pedicle violation was randomly created by an independent investigator in either the anterior, the medial, or the lateral wall in 65 pedicles. Following this, four blinded, independent surgeons at various levels of training probed the specimens on three separate occasions to determine if a breach was present (1296 discrete data points). Surgeon findings were then recorded as breach present or absent and, if present, breach location. The Cohen κ correlation coefficient (κa) and 95% confidence interval were used to assess the accuracy of the observers and the inter- and intraobserver agreement. Results: The mean accuracy over three iterations, the validity in detecting the breach location, and the intraobserver agreement varied by level of training and experience, with the most experienced observer (observer 1) scoring the best and the least experienced observer (observer 4) scoring the worst. The three most senior surgeons had good intraobserver agreement. Interobserver agreement was low between the four observers. Conclusions: An observer's ability to accurately detect the presence or absence of a pedicle tract violation and the breach location, if present, is dependent on the surgeon's level of training. Probing the pedicle tract prior to placement of pedicle screws in the thoracic spine is likely a learned skill that improves with repetition and experience.

Original languageEnglish
Pages (from-to)277-283
Number of pages7
JournalJournal of Spinal Disorders and Techniques
Issue number4
StatePublished - Aug 2004
Externally publishedYes


  • Accuracy
  • Pedicle wall violation
  • Probing
  • Reliability
  • Thoracic pedicle screw


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