ABSTRACT
Objective:To evaluate the effect of oblique lateral interbody fusion (OLIF) combined with posterior fixation on segmental alignment in the treatment of degenerative spondylolisthesis (DS).Methods:The clinical data of 40 patients with DS who underwent OLIF combined with posterior fixation from July 2017 to December 2019 were retrospectively analyzed. There were 7 males and 33 females, aged 45-81 years, with an average age of 65.7±9.06 years. The total number of slip segments was 43, including 37 levels at L 4, 5, 5 levels at L 3, 4, and 1 level at L 2, 3. According to the decompression methods, the patients were divided into two groups. 22 patients with 23 levels were treated with direct decompression combined with laminectomy, and 18 patients with 20 levels were treated with indirect decompression without laminectomy. All patients underwent preoperative and intraoperative imaging examination. The disc height (DH), slip ratio (SR) and segmental lordosis (SL) were measured by preoperative CT and intraoperative fluoroscopy images. One-way repeated measures ANOVA was used to compare the radiographic parameters of the segmental alignment prior to cage implantation, following cage insertion and posterior fixation. Bonferroni test was used to compare the radiographic parameters between groups. Results:In the OLIF combined with the posterior fixation, there were statistically significant differences in the radiographic parameters of segmental alignment at different stages of operation [DH ( F=147.786, P<0.001) , SR ( F=83.754, P<0.001) , SL ( F=38.296, P<0.001) ]. DH increased from 7.99±1.39 mm to 11.69±1.72 mm ( P<0.001), SR decreased from 10.67%±4.67% to 8.66%±4.50% ( P=0.001) and SL increased from 7.26°±2.73° to 7.85°±2.30° ( P=0.425). After combined posterior fixation, SR further decreased from 8.66%±4.50% to 2.07%±4.00% ( P<0.001), SL further increased from 7.85°±2.30° to 10.72°±3.08° ( P<0.001), and DH had no significant change ( P=1.000). There was no significant difference in radiographic parameters between the direct decompression group and the indirect decompression group when prior to cage implantation, following cage insertion and following posterior fixation, respectively. Conclusion:OLIF combined with posterior fixation in the treatment of DS can further reduce the slip rate of patients with lumbar degenerative spondylolisthesis and increase the lordosis angle of the surgical segment. At the same time, the direct decompression combined with laminectomy has no significant effect on the segmental alignment.