Objective:

Intraoperative computed tomography and navigation (iCT-Nav) is increasingly used to aid spinal instrumentation. We aimed to document the accuracy and revision rate of pedicle screw placement across many screws placed using iCT-Nav. We also assess patient-level factors predictive of high-grade pedicle breach.

Methods:

Medical records of patients who underwent iCT-Nav pedicle screw placement between 2015 and 2017 at a single center were retrospectively reviewed. Screw placement accuracy was individually assessed for each screw using the 2-mm incremental grading system for pedicle breach. Predictors of high-grade (> 2 mm) breach were identified using multiple logistic regression.

Results:

1,400 pedicle screws were placed in 208 patients undergoing cervicothoracic (29; 13.9%), thoracic (30; 14.4), thoracolumbar (19; 9.1%) and lumbar (130; 62.5%) surgeries. iCT-Nav afforded high-accuracy screw placement, with 1,356 out of 1400 screws (96.9%) being placed accurately. 37 pedicle screws (2.64%) were revised intraoperatively during the index surgery across 31 patients, with no subsequent returns to the operating room because of screw malpositioning. After correcting for potential confounders, males were less likely to have a high-grade breach (OR=0.21 [0.10-0.59], p=0.003) whereas lateral (OR=6.21 [2.47-15.52], p<0.001) or anterior (OR=5.79 [2.11-15.88], p=0.001) breach location were predictive of a high-grade breach.

Conclusion:

iCT-Nav with post-instrumentation intraoperative imaging is associated with a reduced need for costly postoperative return to the operating room for screw revision. In comparison to studies of navigation without iCT where 1.5-1.7% of patients returned for a second surgery, we report 0 revision surgeries due to screw malpositioning.