Clinical and radiographic outcomes of oblique lateral lumbar interbody fusion and minimally-invasive transforaminal lumbar interbody fusion in patients with grade-1 degenerative spondylolisthesis

Background: The most effective lumbar interbody fusion (LIF) technique for degenerative spondylolisthesis remains controversial. Methods: This is a retrospective study. This comparative analysis included consecutive patients with grade-1 degenerative spondylolisthesis who underwent oblique LIF (OLIF) or minimally-invasive transforaminal LIF (MI-TLIF) at the Department of Spine Surgery, our hospital(January 2016 to August 2017). Patient satisfaction (Japanese Orthopaedic Association score), visual analog scale (VAS) scores for back and leg pain, Oswestry disability index (ODI), radiographic outcomes including anterior/posterior disc heights (ADH/PDH), foraminal height (FH), foraminal width (FW), cage subsidence, cage retropulsion and fusion rate were assessed during a 2-year follow-up. Results: The OLIF and MI-TLIF groups comprised 36 patients (age, 52.1±7.2 years; 27 women) and 45 patients (age, 48.4±14.4 years; 24 women) respectively. Satisfaction rates at 2 years exceeded 90% in both groups. The OLIF group had less intraoperative blood loss (140±36 vs. 233±62 mL), lower back pain VAS score (2.42±0.81 vs. 3.38±0.47) and ODI score (20.47±2.53 vs. 27.31±3.71) at 3 months (with trends toward lower values at 2 years), but higher leg pain VAS scores at all postoperative time points than the MI-TLIF group (all P<0.001). ADH, PDH, FD and FW improved in both groups after surgery. At 2 years, the OLIF group had a higher rate of Bridwell grade-I fusion (100% vs. 88.9%, P=0.046) and lower incidences of cage subsidence (8.33% vs. 46.67%, P<0.001) and retropulsion (0% vs. 6.67%, P=0.046). Conclusions: In patients with grade-I spondylolisthesis, OLIF was associated with less blood loss and better improvements in some clinical(VAS for back pain and ODI) and radiologic outcomes than MI-TLIF, although patients in the OLIF group had higher leg pain VAS scores than patients in the MI-TLIF group.