Accuracy of Augmented Reality Navigation Versus Freehand Pedicle Screw Placement.

Abstract

Study design: Retrospective cohort study.

Objective: To compare the accuracy of augmented reality (AR)-guided and freehand (FH) pedicle screw placement in the lumbosacral spine using computed tomography (CT)-based Gertzbein-Robbins (GRS) grading, and to assess demographic and surgical factors associated with accuracy.

Background: Accurate pedicle screw placement is essential for safe and effective spinal fusion. AR navigation has emerged as an alternative to conventional FH techniques, with potential advantages in accuracy, efficiency, and ergonomics.

Materials and methods: All patients who underwent pedicle screws placement from L1 to S1 using either AR navigation or conventional FH technique, with available postoperative CT imaging for screw accuracy assessment, were analyzed. Demographic and surgical characteristics were compared between both cohorts.

Results: A total of 202 patients were analyzed, comprising 1109 pedicle screws placed (AR: n = 548; FH: n = 561). The proportion of clinically acceptable screws (GRS grade A or B) was significantly higher in the AR group compared with the FH group (99.3% vs . 96.4%; P = 0.013). The rate of clinically unacceptable breaches (GRS grade C-E) was significantly lower in the AR group than in the FH group (0.7% vs . 3.6%; P = 0.013). Level-specific directional summary showed that the highest number of breaches in the AR group occurred at L4, predominantly lateral (n = 24), while in the FH group, breaches were most common at L5 and primarily medial (n = 22). Demographic and surgical characteristics demonstrated no significant differences between the cohorts.

Conclusions: AR-guided navigation was associated with significantly higher pedicle screw placement accuracy compared with conventional FH technique. As the largest study to date directly comparing these approaches, this analysis reinforces the notion that AR may offer more consistent accuracy in screw placement. Further prospective studies are needed to determine its long-term clinical implications.