CT-to-fluoroscopy registration versus scan-and-plan registration for robot-assisted insertion of lumbar pedicle screws.

OBJECTIVE: Pedicle screw insertion for stabilization after lumbar fusion surgery is commonly performed by spine surgeons. With the advent of navigation technology, the accuracy of pedicle screw insertion has increased. Robotic guidance has revolutionized the placement of pedicle screws with 2 distinct radiographic registration methods, the scan-and-plan method and CT-to-fluoroscopy method. In this study, the authors aimed to compare the accuracy and safety of these methods. METHODS: A retrospective chart review was conducted at 2 centers to obtain operative data for consecutive patients who underwent robot-assisted lumbar pedicle screw placement. The newest robotic platform (Mazor X Robotic System) was used in all cases. One center used the scan-and-plan registration method, and the other used CT-to-fluoroscopy for registration. Screw accuracy was determined by applying the Gertzbein-Robbins scale. Fluoroscopic exposure times were collected from radiology reports. RESULTS: Overall, 268 patients underwent pedicle screw insertion, 126 patients with scan-and-plan registration and 142 with CT-to-fluoroscopy registration. In the scan-and-plan cohort, 450 screws were inserted across 266 spinal levels (mean 1.7 ± 1.1 screws/level), with 446 (99.1%) screws classified as Gertzbein-Robbins grade A (within the pedicle) and 4 (0.9%) as grade B (< 2-mm deviation). In the CT-to-fluoroscopy cohort, 574 screws were inserted across 280 lumbar spinal levels (mean 2.05 ± 1.7 screws/ level), with 563 (98.1%) grade A screws and 11 (1.9%) grade B (p = 0.17). The scan-and-plan cohort had nonsignificantly less fluoroscopic exposure per screw than the CT-to-fluoroscopy cohort (12 ± 13 seconds vs 11.1 ± 7 seconds, p = 0.3). CONCLUSIONS: Both scan-and-plan registration and CT-to-fluoroscopy registration methods were safe, accurate, and had similar fluoroscopy time exposure overall.

Mazor X Stealth Robotic Technology: A Technical Note.

BACKGROUND: Minimally invasive techniques in spine surgery have continued to advance as robotic technology has evolved over several generations. Although traditional techniques for placing pedicle screws are still widespread in practice, newer technology has increased the reliability of accurately placing instrumentation with smaller incisions and subsequent decreased length of stay. Additionally, advancements in planning software have improved the ability to align posterior instrumentation to assist with rod placement on multilevel constructs. METHODS: This paper describes the surgical techniques and operative workflow for placing pedicle screws with the latest robotic technology. The robotic platform, registration, surgical planning, and placement of instrumentation are discussed in detail. Advantages of the Mazor X Stealth Edition compared with the previous generation robot include obviating the need for K wires and eliminating the need for a percutaneous pin, as navigation is integrated into the robot. RESULTS: Our use of this new technology has been encouraging. Using the techniques described in this paper, the first 90 pedicle screws placed with the Mazor X Stealth Edition robot yielded 100% grade A accuracy on the Gertzbein-Robbins scale confirmed on immediate postoperative CT. There were no complications experienced in any case. CONCLUSIONS: In our experience, this robotic technology has the potential to improve patient outcomes and is associated with advanced surgical planning compared with more traditional techniques.