Impact of body mass index on perioperative complications, radiographic outcomes, and pseudoarthrosis at one year after transforaminal lumbar interbody fusion: A retrospective cohort study

Obesity rates have been increasing. Patients with high Body Mass Index (BMI) face unique perioperative complications including increased hospital stays, operative time and infection rates. Conflicting studies exist regarding the impact of obesity on patient-reported outcomes (PROMs) and alignment correction. Adult patients who underwent transforaminal interbody fusion (TLIF) at a single academic institution were identified. Patient demographics, procedural characteristics, complications, preoperative to one-year postoperative radiographic parameters and PROMs were compared. Multivariate regression analyses were done, accounting for age, sex, BMI, Charlson Comorbidity Index and number of segments fused. Among 295 patients, 44 had BMI ≤24.9, 92 had 25 ≤ BMI ≤29.9, 75 had 30 ≤ BMI ≤34.9 and 84 had BMI ≥35. With each 10-unit BMI increase, hospital stays increased by 0.54 days ( r = 0.34) and blood loss by 80.47 mL ( r = 0.53) ( p < 0.05). Pseudoarthrosis was 128.0 % more likely with every 10-unit BMI increase ( p < 0.05). AUC of 0.75 (0.62–0.87). Radiographic parameters showed that each 10-unit increase in BMI was associated with 2.21° less L4-S1 lordosis and 2.22° less L1-S1 lordosis change at 1-year follow-up ( p < 0.05). PROMs were similar across BMI groups ( p > 0.05). Higher BMI is associated with higher odds of pseudoarthrosis. Despite decreased lordosis correction, excellent PROMs were achieved across BMI categories. In future studies, BMI as a continuous variable may better predict complications. Additionally, BMI may be considered in preoperative planning for patients undergoing TLIF surgery to optimize outcomes.