Robotic navigated assistance may improve screw times in posterior spinal fusion
Published results showed an improvement in screw times with the use of robotic navigated assistance within the first several cases of posterior spinal fusion.
To evaluate the surgeon learning curve, Darren R. Lebl, MD, MBA, spine surgeon at Hospital for Special Surgery, and colleagues recorded registration, screw placement and positioning times among 65 consecutive adult patients who underwent robotic-navigated posterior spinal fusion (Mazor X Stealth Edition, Medtronic) by a single surgeon from June 2019 to July 2020. All patients underwent intraoperative 3D fluoroscopy, and researchers compared screw trajectory with preoperative CT scans.
Of the 364 instrumented pedicles planned robotically, 85.4% screws were placed robotically, 4.7% were converted to k-wire, 5.8% were converted to freehand and 4.1% were planned freehand. Morphology of starting point, soft tissue pressure, hypoplastic pedicles, obstructive reference pin placement and robotic arm issues were reasons for conversion, according to researchers.
Results showed a significant decrease in time per screw, mean time per screw for each case and average registration time per case as the surgeon gained more experience. Researchers also found screws were placed more accurately over time, with 93.5% and 90.4% of pedicle screws placed robotically in the axial plane and sagittal plane, respectively, fully contained within the pedicle.
Researchers recorded 17 critical breaches in 11 patients, of which 2.9% were due to soft tissue pressure causing skive. Researchers noted 1.9% of patients had critical breaches from hypoplastic pedicles and one patient had unplanned lateral breaches from three screws. Morphology and spinal instability from isthmic spondylolisthesis led to skive in one patient, according to results. Researchers found 46% of screws were placed medial to plan, 54% of screws were placed lateral to plan, 62.1% were placed caudal to plan and 37.9% were placed cranial to plan. Results showed no adverse clinical sequelae occurred from implantation of any screw.
According to Lebl, the results of this study not only identified the amount of time involved for the surgical team to become efficient with robotic navigation and the types of cases most appropriate for its utilization, but it also identified situations and characteristics of when it may be best to convert the robotic technology to a more traditional technique, such as a K-wire-based screw fixation or freehand technique.
“These results help to lay a groundwork for other surgical teams to adopt robotic technologies into their practices and further prove that concept that with higher volume and surgeon experience, surgical techniques are improved and surgical times were lowered,” Lebl told Healio Orthopedics.