Comparative Study of the Effectiveness of MIS TLIF for Degenerative vs. Isthmic Low-Grade Spondylolisthesis: A Subgroup Analysis of Clinical and Radiological Results

Open Access

Abstract

Background: Low-grade spondylolisthesis, whether degenerative or isthmic, is a common cause of disability and pain among adults. Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) has emerged as a standard surgical approach, though comparative outcomes between etiological subgroups remain underreported, particularly in low- and middle-income countries. The current study aimed to compare clinical, radiological, and perioperative outcomes of MIS-TLIF in degenerative versus isthmic low-grade spondylolisthesis. Methods & Materials: This quasi-experimental study was conducted at BSMMU and Popular Medical College Hospital, Dhaka, from March 2022 to September 2024. Included 20 patients (10 degenerative, 10 isthmic) undergoing single-level MIS-TLIF. Baseline characteristics, surgical metrics, and postoperative outcomes were assessed over 12 months using VAS, ODI, Bridwell fusion grading, and Modified Macnab’s criteria. Results: Both groups experienced significant improvements in back and leg pain (VAS) and disability (ODI), with no statistically significant intergroup differences (p > 0.5). Fusion outcomes favored the degenerative group at 12 months (Grade I fusion: 70% vs. 50%), though not significantly (p = 0.18). Clinical outcomes per Macnab’s criteria showed more excellent ratings in degenerative cases (80% vs. 70%). Conclusion: MIS-TLIF is effective for both degenerative and isthmic low-grade spondylolisthesis, offering comparable functional and radiographic results. A mild trend toward superior outcomes in degenerative cases warrants further investigation in larger cohorts.