[Effectiveness of robot-assisted minimally invasive and open freehand transforaminal lumbar interbody fusion in treatment of single-level degenerative lumbar spondylolisthesis and the influence on adjacent segment degeneration].

Objective: To compare the effectiveness of robot-assisted minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) and open freehand TLIF for the treatment of single-level degenerative lumbar spondylolisthesis (DSL) and analyse the influence on postoperative adjacent segmental degeneration (ASD).

Methods: The clinical data of 116 patients with L _4、5 DLS who were admitted between November 2019 and October 2021 and met the selection criteria were retrospectively analyzed. According to the surgical methods, they were divided into the robotic group (45 cases, who underwent robot-assisted MIS-TLIF) and the open group (71 cases, who underwent open freehand TLIF). There was no significant difference in baseline data such as gender, age, body mass index, DLS Meyerding grading, and preoperative Pfirrmann grading, Weishaupt grading, L _{3, 4} intervertebral disc height (DH), L _{3, 4} intervertebral mobility, sagittal parameters [including pelvic incidence (PI), lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT)], and Cage height ( P>0.05). The grade of facet joint violation (FJV) by pedicle screws on the superior articular process was assessed postoperatively. Sagittal parameters, L _{3, 4} DH, L _{3, 4} DH loss, and L _{3, 4} intervertebral mobility were measured preoperatively and at last follow-up in order to determine whether ASD occurred. Based on the occurrence of postoperative ASD, logistic regression analysis was used to identify the risk factors for ASD after TLIF.

Results: Patients in both groups were followed up 21-47 months, with a mean of 36.1 months; there was no significant difference in the follow-up time between the two groups ( P>0.05). The occurrence of postoperative FJV was significantly better in the robotic group than in the open group ( P<0.05). At last follow-up, the difference in the change values of sagittal parameters PI, PT, SS, and LL was not significant when comparing the two groups of patients ( P>0.05); the change values of L _{3, 4} DH and L _{3, 4} DH loss in the robotic group were smaller than those in the open group, and the change value of L _{3, 4} intervertebral mobility was larger than that in the open group, and the differences were significant ( P<0.05). At last follow-up, ASD occurred in 8 patients (17.8%) in the robotic group and 35 patients (49.3%) in the open group, and the difference in ASD incidence between the two groups was significant ( P<0.05). logistic regression analysis showed that open surgery, preoperative Pfirrmann grading Ⅳ-Ⅴ, preoperative Weishaupt grading ≥2, and postoperative FJV grading ≥1 were risk factors for the development of ASD after TLIF ( P<0.05).

Conclusion: Compared with traditional open surgery, orthopedic robot-assisted MIS-TLIF in the treatment of single-level DLS can more accurately insert pedicle screws, reduce the loss of DH and the occurrence of FJV, and effectively reduce the incidence of mid-postoperative ASD. Preoperative disc and synovial joint degeneration in adjacent segments, nonrobotic-assisted minimally invasive therapy, and FJV are risk factors for ASD after TLIF.