Objective: Oblique lateral interbody fusion (OLIF) has become a well-established treatment for lumbar spinal stenosis (LSS) due to its advantages of being minimally invasive, effective, and associated with fewer complications. However, relying solely on lateral fixation provides limited strength and uneven load distribution. Conventional posterior bilateral fixation after OLIF typically requires intraoperative repositioning, increases fluoroscopy frequency, and involves extensive dissection of posterior muscles and soft tissues, resulting in greater trauma, blood loss, and risks of dural tear, nerve root injury, and persistent postoperative low back pain. This study aims to compare the clinical efficacy of robot-assisted single-position OLIF with lateral plating and posterior unilateral fixation, OLIF with lateral fixation alone, and OLIF combined with posterior bilateral fixation for treating single-segment LSS, and to explore how to enhance fixation stability, reduce trauma, and achieve precise minimally invasive outcomes without changing patient positioning.

Methods: A retrospective analysis was conducted on the clinical data from patients treated for single-segment LSS between January 2020 and June 2023 at the First Affiliated Hospital of Kunming Medical University. Patients were divided into 3 groups: Robot group (robot-assisted single-position OLIF with lateral plate and posterior unilateral fixation, 33 cases), lateral group (OLIF with lateral fixation alone, 52 cases), and combined group (OLIF with posterior bilateral fixation, 45 cases). Surgical time, intraoperative blood loss, fluoroscopy frequency, hospital stay, pedicle screw placement accuracy, and complication rates were recorded. Pain visual analogue scale (VAS) scores and Oswestry disability index (ODI) scores were assessed preoperatively, postoperatively, and at the final follow-up. Radiological evaluations (X-ray, computed tomography, and magnetic resonance imaging) measured interbody disc height (IDH), intervertebral foraminal height (IFH), and cross-sectional area (CSA) of the dural sac. Differences between pre- and postoperative imaging indices were statistically analyzed, and complication rates, fusion rates, and cage subsidence rates were recorded.

Results: All patients exhibited good positioning of internal fixation devices and cages, with significant symptom relief and no cases of spinal cord injury or symptom worsening. The follow-up time was (15.2±3.6) months. The operation time of the robot group was (70.62±8.99) min, which was longer than that of the lateral group (45.90±6.09) min and shorter than that of the combined group (110.12±8.44) min. The intraoperative blood loss of the robot group was (44.27±6.87) mL, which was more than that of the lateral group (33.58±9.73) mL and less than that of the combined group (79.19±10.35) mL. The number of intraoperative fluoroscopy times of the robot group was (9.49±2.25), which was comparable to that of the lateral group (7.45±2.02) but less than that of the combined group (12.24±4.25). The hospital stay of the robot group was (9.28±2.10) days, which was longer than that of the lateral group (7.95±1.91) days and shorter than that of the combined group (12.49±5.07) days. The screw placement accuracy of the robot group was 98.48%, which was higher than that of the combined group (90.55%). Postoperative and final follow-up VAS and ODI scores were significantly lower than preoperative scores in all 3 groups (all P<0.05), and there were no significant differences in preoperative VAS and ODI scores among the groups (all P>0.05). Radiologically, IDH, IFH, and CSA at the surgical segment were significantly increased postoperatively and at final follow-up compared to preoperatively and at final follow-up compared to preoperative values (all P<0.05), with no significant differences among the groups postoperatively (all P>0.05). Internal fixation remained stable during the follow-up period, and all cages achieved fusion at final follow-up. The intervertebral fusion rate of the robot-assisted group was 93.40%, which was similar to that of the combined group (95.56%) and higher than that of the lateral approach group (90.34%). The complication rate of the robot-assisted group was 6.1%, which was comparable to that of the combined group (8.9%) and lower than that of the lateral approach group (15.4%) (P<0.05). No cases of fixation loosening or breakage were observed throughout the follow-up period.

Conclusions: Robot-assisted single-position OLIF with lateral plate combined with posterior unilateral fixation effectively achieves indirect decompression and excellent spinal stability without the need for intraoperative repositioning. It provides high pedicle screw accuracy, reduces intraoperative blood loss, fluoroscopy times, and complication rates, offering a fully minimally invasive new treatment option for single-segment LSS.