Accuracy of Pedicle Screw placement in Revision Spine Surgery using Robotic Guidance

Abstract

Introduction Pedicle screw instrumentation in revision spinal surgery can be challenging because of the altered anatomy and existing instrumentation. Malpositioned pedicle screws can result in surgical complications that may lead to persistent pain, dysfunction, and morbidity. Robotic-guided screw placement has been shown to be accurate in the setting of primary surgery, however, less is known about its accuracy in revision situations. The purpose of this study was to identify the accuracy rate of pedicle screws placed via robotic guidance in revision spine surgery. Patients and Methods Patients who underwent revision spinal instrumentation with robotic guidance during a 3-year period (2011–2014) at our institution were identified and included in the study if they had postoperative CT scans of the operated levels. Screw insertion was identified in revision levels and included for analysis if they were categorized as screw redirection, prior fusion without instrumentation, prior laminectomy, or a spinal level adjacent to a previously operated level. Postoperative CT scans were reviewed for pedicle screw accuracy by independent radiologists. Results A total of 36 patients met inclusion criteria (average age 61.6 years, 13 males and 26 females). Of the 682 total pedicle screws placed, 229 were placed in revision levels. Overall, 220 (96.1%) of the 229 revision screws were confirmed to be accurate by postoperative CT. Of the nine screws that were malpositioned, none were clinically significant nor required revision surgery. Of the nine malpositioned screws, there were five lateral breaches, and four medial breaches. One patient required revision surgery for cage migration at a similar level as a misplaced screw, however, pedicle screws were not revised. Conclusion Robotic-assisted pedicle screw placement in revision spinal surgery provides accuracy similar to other techniques in primary cases. In cases of previous laminectomy or fusion, robotic guidance can provide benefit to surgeons in navigating altered bony anatomy. Larger studies are needed to confirm these findings.