Accuracy and Feasibility of Bedrock Configuration Utilizing Mazor X Navigation System

Research Objectives: To prove accuracy and feasibility of utilizing navigation for implantation of S2AI screws and triangular titanium rods in the bedrock configuration during open sacro-pelvic fixation in multilevel spinal fusion for adult spinal deformity.

Design: Retrospective chart review

Setting: Single center, ambulatory care

Participants: 18 adult multilevel spinal deformity patients

Interventions: Reviewed consecutive cases where bilateral S2AI and TTRs were placed in an open approach from 10/2019-9/2020. Patients had preop CT scan for implant planning utilizing Mazor X. S2AI screws were planned into the caudal pelvic teardrop with TTRs placed 1cm proximal and cephalad.

Main Outcome Measures: Preop implant trajectory vs. postop implant placement.

Results: There was no significant difference for the caudal angle in the sagittal plane between pre- and post-operative TTRs and S2AI screws (31.33° ± 3.87° vs. 30.27° ± 3.40°, P = 0.24 and 39.34° ± 2.67° vs 39.32° ± 2.92°, P = 0.98, respectively). For the horizontal angle in the coronal plane there were no significant differences between the pre- and post-operative measurements for the TTRs placed on either the left or right side (38.44° ± 2.49° vs. 40.28° ± 2.88°, P = 0.09 and 40.03° ± 2.45° vs. 38.83° ± 1.85°, P = 0.23; respectively) or for the S2AI screws (36.92° ± 2.76° vs. 38.65° ± 3.19°, P = 0.15 and 39.06° ± 2.35° vs. 38.48° ± 2.24°, P = 0.62; respectively). There were no intraoperative complications and no implants had to be re-positioned.

Conclusions: Placing concomitant bilateral S2AI screws and TTRs in an open approach during multilevel deformity surgery is both feasible and accurate using the Mazor X navigation system.

Author(s) Disclosures: Joshua Herzog, M.D.
William Bader, DMSc, PA-C
Erin Brown, LPN