Early trabecular bone remodeling and paraspinal muscle preservation after unilateral biportal endoscopic versus minimally invasive transforaminal lumbar interbody fusion for mild degenerative lumbar spondylolisthesis: a retrospective comparative study

Objective To compare the clinical and radiological outcomes of unilateral biportal endoscopic transforaminal lumbar interbody fusion (UBE-TLIF) and minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) in the treatment of single-level mild degenerative lumbar spondylolisthesis. Methods A retrospective analysis was conducted on 80 patients with single-level mild degenerative lumbar spondylolisthesis, including 40 patients treated with UBE-TLIF and 40 patients treated with MIS-TLIF. Perioperative parameters, visual analog scale (VAS) scores, Oswestry Disability Index (ODI), modified MacNab scores, fusion rates, trabecular bone remodeling (TBR) at 3 months postoperatively, and multifidus atrophy and fat infiltration rates at 12 months postoperatively were compared between the two groups. Results The UBE-TLIF group had significantly less intraoperative blood loss and shorter hospital stays, but longer operative times compared with the MIS-TLIF group (all P < 0.001). At 3 days postoperatively, the VAS score for low back pain was significantly lower in the UBE-TLIF group than in the MIS-TLIF group (2.98 ± 1.12 vs. 3.62 ± 1.27, P = 0.018), whereas no significant differences were observed between groups in VAS scores at the remaining time points or in ODI scores (all P > 0.05). The UBE-TLIF group showed significantly higher TBR positivity at 3 months and a higher fusion rate at 6 months postoperatively compared with the MIS-TLIF group (P < 0.05), while no significant difference in fusion rate was observed at 12 months. At 12 months postoperatively, the multifidus atrophy rate (29.50 ± 7.72% vs. 34.04 ± 10.55%, P = 0.031) and fat infiltration rate (34.85 ± 7.69% vs. 38.19 ± 6.02%, P = 0.033) were both significantly lower in the UBE-TLIF group than in the MIS-TLIF group. Conclusion Both UBE-TLIF and MIS-TLIF provide satisfactory clinical outcomes in the treatment of single-level mild degenerative lumbar spondylolisthesis. Compared with MIS-TLIF, UBE-TLIF demonstrates certain advantages in early postoperative pain relief, preservation of paraspinal muscles, and early osteointegration during the fusion process.