Comparative Analysis of Robotic-Guided Pedicle Screw Placement Accuracy & Freehand Controls in Percutaneous Adult Degenerative Spinal Instrumentation

Presented at SMISS Annual Forum 2014
By Faissal Zahrawi MD

Disclosures: Faissal Zahrawi MD A; None. B; Spine Wave, LDR, Mazor,Sentio. C; Spine Wave, LDR, Mazor, Sentio. D; None. E; None. F; LDR Spine.

Image-guidance has been the mainstay of minimally invasive spinal surgeries, yet has seen highly variable results in the literature. Robotic-guidance for pedicle screws can reportedly increase placement accuracies and surgical efficiencies, especially in percutaneous approaches. This is a review of the impact of robotics on a surgeon experienced in performing image-guided minimally invasive spinal fusions.

To compare the accuracy of percutaneous pedicle screw placement and post-operative course between robotic-guidance and image-guidance.

Retrospective comparative analysis of medical records of consecutive adult patients suffering from degenerative spine disease treated by percutaneous spinal fusion surgeries. Patients were divided based on whether they were instrumented using robotic-guided or freehand image-guided pedicle screw placement. All were operated by the same surgeon.

Data from 198 patients was collected. Both arms were similar in demographics and surgical indications. The robotic arm had 5.8 screws per case on average and 6.0 (p=0.65) in the control arm. No significant differences were found in post-operative complication rates, revision surgeries, length of stay, duration of surgery, screw implantation times, blood loss or results of Oswestry Disability Index questionnaires. Post-operative CTs were available for 52 patients (253 screws) in the robotic arm and 70 (383 screws) in the freehand controls (table 1). In the robotic arm 100% of screws were found accurately placed within the “safe-zone”, vs. 350 screws (97.1%) in the control arm (p=0.0042). One of 11 breaching screws in the control arm was in group E. This patient did not suffer any sequelae in the 12-month follow-up and was not revised. The follow up period was 9.2±4 months in the robotic-guided arm and 10.5±3 in the control arm. In the robotic-guided arm there was a single revision within 1 week of surgery due to a superficial wound infection. The hardware was not removed or replaced. No other complications or revisions were recorded.

A modest, yet statistically significant, increase in pedicle screw placement accuracy was observed with robotic-guidance, compared to freehand. Larger, prospective studies are needed to demonstrate differences in clinical outcomes.