Impact of Body Mass Index on Operative Outcomes in Head and Neck Free Flap Surgery

Objective Analyze the risk for perioperative complications associated with body mass index (BMI) class in patients undergoing head and neck free flap reconstruction. Study Design and Setting Retrospective cohort study. Subjects and Methods The National Surgical Quality Improvement Program (NSQIP) database was queried for all cases of head and neck free flaps between 2005 and 2014 (N = 2187). This population was stratified into underweight, normal-weight, overweight, and obese BMI cohorts. Groups were compared for demographics, comorbidities, and procedure-related variables. Rates of postoperative complications were compared between groups using χ2 and binary logistic regression analyses. Results Underweight patients (n = 160) had significantly higher rates of numerous comorbidities, including disseminated cancer, preoperative chemotherapy, and anemia, while obese patients (n = 447) had higher rates of diabetes and hypertension. Rates of overall surgical complications, medical complications, and flap loss were insignificantly different between BMI groups. Following regression, obese BMI was protective for perioperative transfusion requirement (odds ratio [OR] = 0.63, P = .001), while underweight status conferred increased risk (OR = 2.43, P < .001). Recent weight loss was found to be an independent predictor of perioperative cardiac arrest (OR = 3.16, P = .006) while underweight BMI was not (OR = 1.21, P = .763). However, both weight loss and underweight status were associated with significantly increased risk for 30-day mortality (OR = 4.48, P = .032; OR = 4.02, P = .010, respectively). Conclusion Obesity does not increase the risk for postoperative complications in head and neck free flap surgery and may be protective in some cases. When assessing a patient’s fitness for surgery, underweight status or recent weight loss may suggest a reduced ability to tolerate extensive free flap reconstruction.