237. Robotic-guided placement of cervical pedicle screws: feasibility and accuracy

Abstract

BACKGROUND CONTEXT It has been shown that pedicle screw instrumentation in the cervical spine has superior biomechanical pullout strength and stability. However, due to the complex and variable anatomy of the cervical pedicles and the risk of catastrophic complications, cervical pedicle screw placement is not widely utilized. PURPOSE The purpose of this study is to review and report our experience with robotic guided cervical pedicle screw placement. STUDY DESIGN/SETTING We retrospectively reviewed consecutive patients who underwent cervical pedicle screw fixation with robotic guidance using pre- and postoperative CT scans by the investigator. Medical charts were reviewed for technical issues and intraoperative complications. PATIENT SAMPLE A total of 62 cervical pedicle screws were reviewed in eight consecutive patients. OUTCOME MEASURES Screw placement and deviation (mm) from the preoperative plan were assessed.We also reviewed the Medical charts for technical issues and intra-operative complications. METHODS Screw placement and deviation from the preoperative plan were assessed using the robotic system's planning software by fusing the preoperative CT (with the planned cervical pedicle screws) to the postoperative CT. This process was carried out by manually aligning the anatomical landmarks on the two CTs. Once a satisfactory fusion was achieved, the software's measurement tool was used manually to compare the planned vs actual screw placements in both axial and sagittal planes, at the midpoint of the pedicle in a resolution of 0.1 millimeters. Medical charts were reviewed for technical issues and intraoperative complications. RESULTS A total of 62 cervical pedicle screws were reviewed in eight patients. The patients’ mean age was 65 years, M:F ratio was 1:1, and the mean BMI was 25.17. No intraoperative complications that related to the placement of cervical pedicle screws were reported and robotic-guidance was successful in all 62 screws. The number of screws placed were 8 at C2, 12 at both C3 and C4, 10 at C5, 11 at C6, and 9 at C7. Postoperative CT scans showed that there were ten pedicle screw breaches (16.1%), all were medial, all less than 1 mm, with no clinical consequences. No pedicle screw breached the foramen transversarium. In the axial plane, the left side screws deviated from the pre-operative plan by 1.2±0.76 mm and the right-side screws deviated from the preoperative plan by 1.4±1.16 mm. In the sagittal plane, the left side screw deviated from the pre-operative plan by 1.2±1.16 mm and the right-side screw deviated from the preoperative plan by 1.4±0.94 mm. CONCLUSIONS This study indicates that robotic-guided cervical pedicle screw placement is feasible with clinically acceptable results. The medial breaches did not result in any clinical consequences akin to passing a sublaminar wire or placing a hook into the epidural space. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.