Unilateral biportal endoscopic lumbar fusion versus minimally invasive transforaminal lumbar interbody fusion for single-level mild to moderate lumbar spondylolisthesis: a retrospective study

To compare the early clinical outcomes and radiographic outcomes of unilateral biportal endoscopic transforaminal lumbar interbody fusion (ULIF) versus minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) in the treatment of single-level mild to moderate lumbar spondylolisthesis (LS). Clinical data of patients with single-level lumbar spondylolisthesis who underwent ULIF or MIS-TLIF at Shandong Provincial Hospital Affiliated to Shandong First Medical University between January 2018 and August 2025 were retrospectively analyzed, including 33 patients in the ULIF group and 33 patients in the MIS-TLIF group. The baseline characteristics, perioperative parameters and radiographic outcomes were compared between the two groups. All surgeries were successfully completed in all patients. The operative time was significantly longer in the ULIF group than in the MIS-TLIF group ( P < 0.05). However, the ULIF group had significantly less intraoperative blood loss, postoperative drainage volume, and shorter postoperative hospital stay compared with the MIS-TLIF group (all P < 0.05). In the early postoperative period, the levels of C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were significantly lower in the ULIF group than in the MIS-TLIF group ( P < 0.05). Compared with preoperative baseline values, the Visual Analogue Scale (VAS), Oswestry Disability Index (ODI), and Japanese Orthopaedic Association (JOA) scores improved significantly at all postoperative time points in both groups (all P < 0.05). Nevertheless, the VAS scores for low back pain and leg pain at 3 days postoperatively were significantly lower in the ULIF group than in the MIS-TLIF group ( P < 0.05). Radiographically, all radiographic parameters improved significantly postoperatively in both groups compared with preoperative values ( P < 0.05), with no statistically significant differences observed between the two groups ( P > 0.05). The efficacy of ULIF in the treatment of single-level mild to moderate lumbar spondylolisthesis is comparable to that of MIS-TLIF. However, the ULIF group is associated with less intraoperative blood loss, less postoperative drainage, and faster postoperative recovery, albeit with a longer operative time.