Comparing Cortical Bone Trajectories for Pedicle Screw Insertion using Robotic Guidance and Three-Dimensional Computed Tomography Navigation

Background: Cortical bone trajectories (CBTs) for pedicle screw insertion can be used to stabilize the spine. Surgeons often rely on fluoroscopy or computed tomography (CT)-navigation technologies to guide screw placement. Robotic technology has potential to increase accuracy. We report our initial experience with robotic guidance for pedicle screw insertion utilizing CBTs in patients with degenerative disc disease.

Methods: A retrospective chart review was conducted using data for consecutive patients who underwent spinal stabilization using a posterior approach for CBTs. The newest robotic platform (Mazor X) was used in these cases. Accuracy was determined by applying the Ravi Scale: grade I (no breach or deviation), II (breach <2 mm), III (breach 2-4 mm), or IV (breach >4 mm). The results were compared with those for a historical cohort of patients who underwent CT navigation-guided pedicle screw insertion using CBTs.

Results: Twenty-two patients underwent robot-assisted pedicle screw placement using CBTs. A total of 92 screws were inserted across 24 spinal levels with grade I accuracy and without complications in the robotic group. Eighteen patients underwent CT-navigation for CBT pedicle screw insertion. A total of 74 screws were inserted across 19 levels, 69 of which were grade I accuracy and 5 were grade II accuracy. When comparing operative time (P = 0.97), fluoroscopy time (P = 0.8), and radiation dose (P = 0.4), no significant differences were observed between cohorts.

Conclusions: Robotic technology and CT-navigation technology for CBT pedicle screw insertion were safe and accurate.