Accuracy of Robot-Assisted Percutaneous Pedicle Screw Placement for Treatment of Lumbar Spondylolisthesis: A Comparative Cohort Study

BACKGROUND With the in-depth development of minimally invasive spine surgery in recent years, robot- and computer-assisted technologies have been increasingly used and successfully applied to spinal surgery. MATERIAL AND METHODS We performed a retrospective analysis of 60 patients with grade I or II lumbar spondylolisthesis who underwent minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) from January 2017 to December 2017. A robot-assisted surgical system was used in 30 patients for pedicle screw placement. The other 30 patients underwent fluoroscopy-guided percutaneous pedicle screw placement. RESULTS There were 130 screws placed under fluoroscopic guidance, with 26.2% penetration of the pedicle wall. There were 130 screws placed in robotic-assisted surgery, with 6.2% penetration of the pedicle wall. Severe screw deviation (Neo grade III) was identified in 4 screws in the fluoroscopy-guided group, while no severe deviation was noted in the robot-assisted group. In the fluoroscopic group, 15.6% of screws penetrated the superior articular process, and 2.1% screws had severe complications (Babu grade III). However, only 5.1% of screws in the robot-assisted group had severe complications. The mean screw insertion angle was significantly greater in the robot-assisted group than in the fluoroscopy-guided group (23.8±6.1° vs. 18.4±7.2°, P=0.017). CONCLUSIONS Compared to fluoroscopy-guided percutaneous pedicle screw placement, robot-assisted percutaneous pedicle screw placement has the following advantages: greater accuracy, lower incidences of screw penetration of the pedicle wall and invasion of the facet joints, and better screw insertion angle. Combined with MIS-TLIF, robot-assisted percutaneous pedicle screw placement is an effective minimally invasive treatment for lumbar spondylolisthesis.