Abstract:Objective To evaluate the therapeutic effects of oblique lateral interbody fusion (OLIF) and minimally invasive transforminal lumbar interbody fusion (MIS-TLIF) on degenerative lumbar spondylolisthesis (DLS) in the elderly based on spinal pelvic anatomy and lumbar spondylolisthesis mechanics. Methods A retrospective study was conducted on 122 elderly patients with DLS who underwent surgical treatment in Cangzhou Hospital of Integrated Chinese and Western Medicine from April 2020 to March 2022. Fifty-nine patients who received OLIF surgery were as OLIF group, while 63 patients who received MIS-TLIF surgery were as MIS-TLIF group. The clinical data of operation, pre-operation, immediately after operation and 12 months after operation were collected from two groups of patients, including the spondylolisthesis parameters ［intervertebral height (DH), local kyphosis angle (SK), lumbar spondylolisthesis rate (SP), spondylolisthesis angle (SA)］, lumbar pelvic anatomical parameters ［L1 distance between the center of the vertebral body and the perpendicular line of the sacrum (LASD), lumbar lordosis angle (LL), sacral inclination angle (SS), pelvic inclination angle (PT) and pelvic incidence angle (PI)］. Visual Analogue Scale for Pain (VAS) score and the Oswestry Dysfunction Index (ODI) were used to assesse pain perception and lumbar function. Results Compared with the MIS-TLIF group, the OLIF group had shorter operative time, hospital stay and incision length, less intraoperative bleeding and postoperative drainage flow (P＜0.01). In immediate period and 1 year after surgery compared to preoperative levels, both groups of patients showed an increase in DH, a decrease in SK, SP and SA (P<0.05), and a significant decrease in LASD and PT, a significant increase in LL and SS (P<0.05), but no significant change in PI (P>0.05); the VAS score and ODI decreased significantly (P＜0.05). At the same time point after surgery, the OLIF group had a larger DH and a smaller SK compared with the MIS-TLIF group (P＜0.01), and there was no significant difference in other mechanical parameters of spondylolisthesis， lumbar pelvic anatomy parameters, VAS score and ODI between the two groups (P＞0.05). Conclusion OLIF and MIS-TLIF have good improvement effects on the spine pelvic anatomy, mechanical parameters of lumbar spondylolisthesis, pain degree, and lumbar function in elderly patients with DLS, and the effects are similar, but when using OLIF, the operation time, hospitalization time, and incision length are shorter, and the intraoperative blood loss and postoperative drainage are less, which has obvious advantages.