Accuracy of powered surgical instruments compared with manual instruments for pedicle screw insertion: Evaluation...

Though powered surgical instruments for pedicle screw insertion combined with navigation have been developed to reduce time taken for spine surgery, clinical evidence demonstrating the safety and effectiveness of powered surgical instruments is limited. The goals of the present study were to compare the accuracy of powered instruments and manual instruments using O-arm-based navigation in surgery for scoliosis.

We retrospectively identified 60 consecutive patients with adolescent idiopathic scoliosis who underwent posterior corrective surgery using O-arm based navigation, collected from Jun 2013 to Feb 2015. Overall, 393 screws were tapped and inserted in 30 patients using manual instruments (group M) and 547 screws were tapped and inserted in 30 patients using powered instruments (group P). Postoperative computed tomography was used to assess screw accuracy using the established Neo classification (Grade 0, no perforation; Grade 1, perforation <2 mm, Grade 2: perforation ≥2 and <4 mm, Grade 3: perforation ≥4 mm). The time to position one screw, including registration, was calculated.

In group M, 331 (84%) of the 393 pedicle screw placements were categorized as Grade 0, 49 (13%) were Grade 1, 13 (3.3%) were Grade 2, and 0 were Grade 3. In group P, 459 (84%) of the 547 pedicle screw placements were categorized as Grade 0, 75 (14%) were Grade 1, 13 (2.4%) were Grade 2, and 0 were Grade 3. We found no significant difference in the prevalence of Grade 2-3 perforations between groups. The time to insert one pedicle screw was 5.4 ± 1.4 min in group M, but significantly decreased to 3.4 ± 1.2 min in group P.

Our results demonstrate that powered instruments using O-arm navigation insert pedicle screws as accurately as conventional manual instruments using O-arm navigation. The use of powered instruments requires less time in O-arm surgery for scoliosis.