Introduction: The study is a retrospective cohort analysis of patients having undergone extreme lateral interbody fusion (XLIF). XLIF is a minimally invasive surgical approach for lumbar spinal surgery used primarily for degenerative disease. Due to the increasing prevalence of obesity, BMI has gained importance as a possible pre-operative parameter affecting surgical outcomes. The evidence regarding the use of BMI as an independent preoperative predictor of complication rate has been varied and conflicting. The primary objective is to determine the effects of body mass index (BMI) as an independent predictor of postoperative complication rate following XLIF surgery. The secondary objective is to examine obesity as a predictor of postoperative pain and disability outcomes.
Methods: The study population was divided into BMI =30 and BMI <30 groups. Primary outcomes recorded were surgical revision, subsidence, fusion, perioperative complications, and neurological complications including psoas muscle weakness, anterior thigh numbness, and radiculopathy. Secondary outcomes included Oswestry Disability Index (ODI) scores. Patients were followed to 1 year post-op.
Results: There was not enough evidence to conclude a significant relationship between BMI and surgical revision or subsidence. There was not enough evidence to conclude that BMI =30 had an effect on overall complication rate, perioperative complication rate, fusion rate, and neurological complication rate following logistic regression. There was no evidence to conclude that the average ODI is statistically different between the BMI =30 group and the BMI <30 group after adjusting for baseline ODI.
Conclusions: Based on this study, there was no support for BMI =30 leading to an increased risk of complication or increased pain and disability. It is possible that a significant difference may be observed using a higher BMI cutoff value or by examining bone density as an independent predictor of revision, subsidence, and fracture.
Patient Care: Patients with BMI >30 can still undergo XLIF.
Learning Objectives: 1) There was not enough evidence to conclude a significant independent relationship between BMI and overall complication rate, surgical revision rate, subsidence rate, perioperative complication rate, fusion rate, or neurological complication rate.
2) There was no evidence to conclude that the average ODI or VAS is statistically different between the BMI =30 group and the BMI <30 group after adjusting for the baseline measure.
3) Based upon this study, there is no support for BMI =30 as an independent risk factor for complications or increased pain and disability following XLIF surgery.