Obesity and Clinical, Radiographic, and Surgical Outcomes After Minimally Invasive Single-Level Transforaminal versus Lateral Lumbar Interbody Fusion

To determine the effect of obesity on clinical, radiographic, and surgical outcomes after lateral lumbar interbody fusion (LLIF) versus minimally invasive surgery (MIS) transforaminal lumbar interbody fusion (TLIF) and compare the effectiveness of LLIF versus MIS TLIF in treating obese patients. A retrospective comparative analysis of patients who underwent single-level L4-5 LLIF or MIS TLIF over a 7-year period was performed. Spinopelvic parameters were compared based on pre- and postoperative radiographs. Body mass index (BMI) ≥30 was deemed "high"; BMI <30 was deemed "low." In total, 154 patients underwent LLIF or MIS TLIF during the study period (33 TLIF high BMI, 45 TLIF low BMI, 28 LLIF high BMI, and 48 LLIF low BMI). Compared with TLIF high BMI patients, TLIF low BMI patients experienced superior posterior disc height (PDH) restoration (p=0.05), shorter operative duration (p=0.01), decreased revision surgery rate (p=0.02), reduced estimated blood loss (p=0.04), and shorter hospital length of stay (p=0.03). No differences in outcomes were seen in LLIF high BMI vs LLIF low BMI cohorts. Among obese patients, LLIF provided superior restoration in anterior disc height (p<0.001), PDH (p=0.003), and neuroforaminal height (p=0.002); shorter operative duration (p<0.001); and decreased estimated blood loss (p=0.008), compared with MIS TLIF. Obesity was associated with poorer overall radiographic and surgical outcomes after MIS TLIF but not LLIF. In obese patients in our cohort, LLIF provided superior improvements in spinopelvic parameters and surgical characteristics. BMI should be considered when deciding between LLIF and MIS TLIF.