Accuracy and deviation analysis of robot-assisted spinal implants: A retrospective overview of 105 cases and preliminary comparison to open freehand surgery in lumbar spondylolisthesis.

BACKGROUND

Whether the accuracy of robot-assisted spinal screw placement is significantly higher than that of freehand and the source of robotic deviation remain unclear.

METHODS

Clinical data of 105 patients who underwent robot-assisted spinal surgery was collected, and screw accuracy was evaluated by computed tomography according to the modified Gertzbein-Robbins classification. Patients were grouped by percutaneous and open surgery. Intergroup comparisons of clinical and screw accuracy parameters were performed. Reasons for deviation were determined. Thirty-one patients with lumbar spondylolisthesis undergoing open robot-assisted surgery and the same number of patients treated by open freehand surgery were compared for screw accuracy.

RESULTS

Screw accuracy was not significantly different between the percutaneous and open groups in both intra- and postoperative evaluations. Tool skiving was identified as the main cause of deviation. The proportion of malpositioned screws (grade B + C + D) was significantly higher in the freehand group than in the robot-assisted group. However, remarkably malpositioned (grade C + D) screws showed no significant differences between the groups. No revision surgery was necessary.

CONCLUSIONS

Robot-assisted spinal instrumentation manifests high accuracy and low incidence of nerve injury. Tool skiving is a major cause of implant deviation.