Does minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) influence functional outcomes and spinopelvic parameters in isthmic spondylolisthesis?

Purpose We assessed the efficacy of minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) in patients with low-grade isthmic spondylolisthesis. Methods We included 24 symptomatic patients who underwent MIS-TLIF between December 2017 and December 2020. Patients were followed up clinically by the Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) for back and VAS for leg pain, as well as radiological radiographs after 6 weeks, 6 months, and at final follow-up (at least 12 months). Measured parameters included C7 sagittal vertical axis (SVA), pelvic tilt (PT), pelvic incidence (PI), sacral slope (SS), Meyerding slip grades, lumbar lordosis (LL), L1-L4 angle, L4-S1 angle, and segmental lordosis (SL) of the affected segment. The mismatch between the PI and LL was also measured. Results VAS for back, VAS for leg pain, and ODI significantly improved postoperatively (all p < 0.001). We observed significantly decreased mean values of PT and slip percentage and increased mean values of SS and LL (all p < 0.05). We observed a significant reduction in L1-L4 lordosis and a significant increase in L4-S1 lordosis. The final PT, SS, and LL (total and L1-L4) were significantly higher in group III patients (n = 15) than the values of group II patients (n = 9). None of the patients became unbalanced postoperative, and all patients had a normal matching between the PI and the LL postoperatively. Conclusions MIS-TLIF is a safe procedure for managing low-grade isthmic spondylolisthesis with significant improvement in clinical and radiological outcomes. It can correct and maintain a proper spinopelvic alignment.