Intraoperative Cone Beam CT in Hybrid Operating Room Set-Up as an Alternative to Postoperative CT for Pedicle Screw Breach Detection

Author(s): Simon Peh, Julian Pfarr, Mathis Wegner, Jost Philipp Schäfer, Jan-Hendrik Christensen, Anindita Chatterjae, Rami Nachabe, Andreas Seekamp, Sebastian Lippross

Background: CT is considered the gold standard for detecting pedicle breach. However, CBCT may be a viable and low radiation dose alternative to provide intraoperative feedback to surgeons to permit in-room revisions of misplaced screws.

Methods: To assess the ability and reliability of intraoperative cone-beam CT (CBCT) from a robotic C-arm in a hybrid operating room (OR) two hundred forty-one pedicle screws were inserted in cervical, thoracic and lumbar spine of 7 cadavers followed by CBCT and CT imaging. The CT images served as the standard of reference. Agreement on screw placement between both imaging systems was assessed using Cohen’s Kappa coefficient (κ). Sensitivity, specificity, receiver operating characteristic (ROC), area under the empirical and fitted ROC curves (AUC) were computed to assess CBCT as a diagnostic tool compared to CT. The patient effective radiation dose (ED) was calculated for comparison. A systematic literature review was performed to provide perspective to the obtained results.

Results: Almost perfect agreement in assessing pedicle screw grading between CBCT and CT was observed (κ=0.84). The sensitivity and specificity of CBCT were 0.84 and 0.98 respectively. The AUC derived from the empirical and fitted ROC curves were 0.95 and 0.96.

Conclusion: Intraoperative CBCT by C-arm in a hybrid OR is highly reliable in identification of screw placement at significant dose reduction.