Decreasing the Pedicle Screw Misplacement Rate in the Thoracic Spine With Robot-guided Navigation.

STUDY DESIGN: A retrospective chart review. OBJECTIVE: The aim of this study was to evaluate the screw accuracy of thoracic pedicle screws placed with a robot-guided navigation system. SUMMARY OF BACKGROUND DATA: Thoracic pedicles are smaller in diameter than lumbar pedicles, making pedicle screw placement difficult. Misplaced pedicle screws may present complications including decreased construct stability, and increased risks of neurological deficits and blood vessel perforation. There is a dearth of knowledge on thoracic pedicle screw accuracy placed with a robot. MATERIALS AND METHODS: A retrospective analysis of the robot-assisted placement of thoracic pedicle screws was performed. Preoperative and postoperative computed tomography (CT) scans of the implanted thoracic screws were collected to assess screw placement accuracy, pedicle breadth, and placement deviations. A CT-based Gertzbein and Robbins System was used to classify pedicle screw accuracy in 2 mm increments. A custom image overlay software was used to determine the deviations between the preoperatively planned trajectory of pedicle screws and final placement at screw entry (tail), and tip in addition to the angular deviation. RESULTS: Seventy-five thoracic pedicle screws were implanted by navigated robotic guidance in 17 patients, only 1.3% (1/75) were repositioned intraoperatively. Average patient age and body mass index were 57.5 years and 25.9 kg/m 2 , respectively, with 52.9% female patients. Surgery diagnoses were degenerative disk disease (47.1%) and adjacent segment disease (17.6%). There were zero complications, with no returns to the operating room. According to the CT-based Gertzbein and Robbins pedicle screw breach classification system, 93.3% (70/75) screws were grade A or B, 6.6% (5/75) were grade C, and 0% were grade D or E. The average deviation from the preoperative plan to actual final placement was 1.8±1.3 mm for the screw tip, 1.6±0.9 mm for the tail, and 2.1±1.5 degrees of angulation. CONCLUSIONS: The current investigation found a 93.3% accuracy of pedicle screw placement in the thoracic spine. Navigated robot assistance is a useful system for placing screws in the smaller pedicles of the thoracic spine. LEVEL OF EVIDENCE: Level III-retrospective nonexperimental study.

Factors Affecting the Accuracy of Pedicle Screw Placement in Robot-Assisted Surgery: A Multicenter Study.

STUDY DESIGN: Retrospective multicenter. OBJECTIVE: The aim was to investigate the factors involved in, and their relative contributions to, the overall accuracy of robot-assisted pedicle screw placement. SUMMARY OF BACKGROUND DATA: Robot-assisted surgery has reportedly resulted in greater accuracy for placement of pedicle screws than conventional methods. There are many potential factors affecting the accuracy of pedicle screws placed with a robot. No study has investigated these factors in a robust way. MATERIALS AND METHODS: Radiographic and clinical data of three centers were pooled. Preoperative and postoperative computerized tomographies were obtained by all three centers to assess the accuracy of the placed screws. The primary outcome measured was accuracy of pedicle screws placed with the robot. The authors performed a multivariate regression analysis to determine the significant patient-related and screw-related variables and their relative contribution to the overall accuracy. In addition, an ordinal regression analysis was conducted to investigate the effects of different variables on accuracy of robot-placed screws graded by Gertzbein-Robbins grading system (GRS). RESULTS: The total contribution of all studied variables to overall accuracy variation as measured by offsets between the placed and planned screws was only 18%. Obesity, long constructs, female gender, surgeon, and vertebral levels were among the factors that had small contributions to the different screw offsets. For GRS grades, significant variables were gender (Log odds: 0.62, 95% CI: 0.38-0.85), age (Log odds: 0.02, 95% CI: 0.01-0.03), length of constructs (Log odds: 0.07, 95% CI: 0.02-0.11), screw diameter (Log odds: 0.55, 95% CI: 0.39-0.71), and length of the screws (Log odds: 0.03, 95% CI: 0.01-0.05). However, these variables too, regardless of their significant association with the accuracy of placed screws, had little contribution to overall variability of accuracy itself (only about 7%). CONCLUSION: The accuracy of screws placed with robotic assistance, as graded by GRS or measured offsets between planned and placed screw trajectories, is minimally affected by different patient-related or screw-related variables due to the robustness of the robotic navigation system used in this study. LEVEL OF EVIDENCE: Level III.

Navigated robotic assistance improves pedicle screw accuracy in minimally invasive surgery of the lumbosacral spine: 600 pedicle screws in a single institution.

BACKGROUND: In the emerging field of robot-assisted spine surgery, radiographic evaluation of pedicle screw accuracy in the surgical setting is of high interest. Advances in medical imaging have improved the accuracy of pedicle screw placement, from fluoroscopy-guided to computer-aided navigation. METHODS: A retrospective, institutional review board-exempt review of the first 106 navigated robot-assisted spine surgery cases was performed. Radiographic evaluation of preoperative and postoperative computerized tomography (CT) scans were collected. RESULTS: In the first 106 cases, 630 lumbosacral pedicle screws were placed. Thirty screws were placed in five patients without the robot because of surgeon discretion. Of the 600 pedicle screws inserted by navigated robotic guidance, only 1.5% (9/600) were repositioned intraoperatively. CONCLUSION: This study demonstrated a high level of accuracy (98.2%) in terms of grade A or B pedicle screw breach scores in the clinical use of navigated, robot-assisted surgery in its first 101 cases.

Pedicle screw accuracy in clinical utilization of minimally invasive navigated robot-assisted spine surgery.

In the emerging field of robot-assisted spine surgery, the radiographic evaluation of pedicle screw accuracy in clinical application is an area of high interest. This study describes the pedicle screw accuracy of the first 56 consecutive cases in which navigated robotic assistance was used in a private practice clinical setting. A retrospective, Institutional Review Board-exempt review of the first 56 navigated robot-assisted spine surgery cases was performed. Pedicle screw malposition, reposition, and return to operating room (OR) rates were collected. A CT-based Gertzbein and Robbins system (GRS) was used to classify pedicle screw accuracy. In the first 56 robotic cases, 356 total pedicle screws were placed. Eight screws were placed without the robot due to surgeon discretion. Of the 348 pedicle screws inserted by navigated robotic guidance, only 2.6% (9/348) were repositioned, resulting in a 97.4% (339/348) successful screw placement rate. The average age was 64, and 48% were female. Average body mass index was 31 kg/m2. Based on the GRS CT-based grading, 97.7% (340/348) were graded A or B, 1.7% (6/348) screws were graded C, and only 0.6% (2/348) of screws were graded D. Two complications, explantation of interbody and vacuum-assisted wound closure, were reported as requiring a return to the OR, but these were not related to robotic guidance or pedicle screws. This study demonstrated a high level of accuracy (97.7%) in the first 56 cases using navigated, robot-assisted surgery based on the GRS. There were two non-screw-related complications requiring return to the operating room.

Does the accuracy of pedicle screw placement differ between the attending surgeon and resident in navigated robotic-assisted minimally invasive spine surgery?

Robotic assistance with integrated navigation is an area of high interest for improving the accuracy of minimally invasive pedicle screw placement. This study analyzes the accuracy of pedicle screw placement between an attending spine surgeon and a resident by comparing the left and right sides of the first 101 consecutive cases using navigated robotic assistance in a private practice clinical setting. A retrospective, Institutional Review Board-exempt review of the first 106 navigated robot-assisted spine surgery cases was performed. One attending spine surgeon and one resident performed pedicle screw placement consistently on either the left or right side (researchers were blinded). A CT-based Gertzbein and Robbins system (GRS) was used to classify pedicle screw accuracy, with grade A or B considered accurate. There were 630 consecutive lumbosacral pedicle screws placed. Thirty screws (5 patients) were placed without the robot due to surgeon discretion. Of the 600 pedicle screws inserted by navigated robotic guidance (101 patients), only 1.5% (9/600) were repositioned intraoperatively. Based on the GRS CT-based grading of pedicle breach, 98.67% (296/300) of left-side screws were graded A or B, 1.3% (4/300) were graded C, and 0% (0/300) were graded D. For the right-side screws, 97.67% (293/300) were graded A or B, 1.67% (5/300) were graded C, and 0.66% (2/300) were graded D. This study demonstrated a high level of accuracy (based on GRS) with no significant differences between the left- and right-side pedicle screw placements (98.67% vs. 97.67%, respectively) in the clinical use of navigated, robot-assisted surgery.

Robot-Assisted Pedicle Screw Placement: Learning Curve Experience.

OBJECTIVES: To describe the learning curve of pedicle screw placement using robot-assisted spine surgery of an experienced neurosurgeon and 2 supervised neurosurgical fellows. METHODS: The first 120 cases of robot-assisted spine surgery at our institution were assessed. Patient variables included age, body mass index, and indication for surgery. Intraoperative variables included the vertebral level of screw placement, number of screws placed by each operator, intraoperative blood loss, and operative time. Postoperative variables included length of stay, discharge disposition, 30-day readmissions, wound complications, and hardware revisions. Screw accuracy was determined with image overlay analysis comparing planned screw trajectory on the navigation software with the intraoperative computed tomography scan with final screw placement. Two-dimensional accuracy was determined for the tip of the screw, tail of the screw, and angle at the screw was placed. The supervising physician and first fellow began utilizing the robot concurrently upon its arrival, and the second fellow began using the robot after the system had been in place for 7 months. RESULTS: Both experienced surgeon and first fellow displayed a learning curve and achieved statistically significant improvement of accuracy after 30 screws. The second fellow had significantly better accuracy than the experienced surgeon in his first 30 screws. There were no complications from hardware placement in either group. There were no returns to the operating room for hardware issues. CONCLUSIONS: Robot-assisted spine surgery is a safe, accurate method of pedicle screw instrumentation. Our data show similar learning adaptation rates for the first fellow and the experienced surgeon. Techniques learned by the attending surgeon were immediately transferable to a new learner, who was able to achieve a faster learning curve than both the first fellow and the experienced surgeon.