GP4d - The Obesity Paradox in Fibular Free-Tissue Reconstruction: Does Higher BMI Improve Outcomes?

Abstract: Head and neck squamous cell carcinoma (HNSCC) incidence is expected to increase 30% by 2030. Concurrently, 45% of Americans (as of 2018) have at least one chronic disease, including obesity-related diabetes and hypertension. As fibular free-tissue reconstruction has become the standard surgical approach for the management of head and neck defects following HNSCC resection, the impact of body mass index (BMI) on surgical outcomes in these procedures remains underexplored. To improve the care of this patient population, this study aims to explore the relationship between BMI, hospital length of stay, and perioperative complications.

The study was a retrospective multi-institutional cohort study using the American College of Surgeons National Surgical Quality Improvement Program database to enroll patients who underwent radical excision of malignant mandible tumors with free myocutaneous and fibular flap reconstruction from 2012 to 2022. The primary independent variable was BMI and patients were stratified into underweight ( <18.5), normal-weight (18.5–25.0), and overweight/obese (>25.0) categories. Descriptive, univariate, and multiple logistic regression statistics were used to evaluate the relationship between BMI, operative time, hospital stay length, and perioperative complications.

Descriptive statistics characterized patient demographics and clinical variables. Bivariate analysis was conducted to compare hospital stays, perioperative complications, and readmission rates across BMI categories. Multivariate regression models, adjusted for potential confounders (eg, age, sex, smoking, diabetes), examined the independent influence of BMI on surgical outcomes. Statistical significance was defined as P < .05. All analyses were performed using Stata 18.5.

The study analyzed 4,808 patients. The cohort was comprised of 58.2% overweight/obese, 36.5% normal weight, and 5.3% underweight individuals. Overweight/obese patients had shorter hospital stays (9.33 ± 0.13 days, P = .03) compared to normal-weight patients (10.33 ± 0.19 days). The risk of perioperative complications varied: underweight patients had the highest complication rates (n = 141, 55.3%, P < .001), while overweight/obese patients had the lowest (n = 806, 28.8%, P < .001), compared to normal-weight patients (n = 673, 38.4%). Overweight/obese patients experienced fewer infectious (n = 442, 15.8%, P < .001) and wound-related (n = 99, 3.5%, P = .03) complications compared to normal-weight counterparts (n = 344, 22.8% and n = 85, 4.8%, respectively). Underweight patients experienced more respiratory-related (n = 21, 8.2%, P = .03) and transfusion-related (n = 90, 36.3%, P < .001) complications compared to normal-weight counterparts (n = 86, 4.9% and n = 386, 22.8%, respectively). The 30-day readmission rate was higher for underweight patients (n = 36, 14.1%, P = .02) and lower for overweight/obese patients (n = 208, 7.4%, P = .02) compared with normal weight patients (n = 166, 9.5%). Multivariate analysis confirmed that overweight/obese patients had statistically significant shorter hospital stays (β -1.0 days, 95% CI -1.5 to -0.5, P < .001) and a decreased likelihood of complications (β -10.5%, 95% CI -6.3% to -1.8%, P < .001) compared to normal-weight patients, suggesting a potential protective effect of higher BMI.

This study identified a paradoxical relationship between obesity and surgical outcomes in HNSCC patients undergoing fibular free-tissue reconstruction. Overweight/obese patients demonstrated better postoperative recovery metrics, including shorter hospital stays and reduced complication rates. Underweight patients exhibited the highest perioperative risk profiles.

This underscores the need to contextualize BMI in preoperative risk assessments. The findings align with the “Obesity Paradox,” where higher BMI may confer resilience via increased metabolic reserves and modulated inflammatory responses. However, the results challenge conventional assumptions about obesity and surgical risk. Tailored perioperative management strategies are essential to improve outcomes across BMI categories. Future studies should investigate the underlying mechanisms of the Obesity Paradox and its implications for broader surgical populations.

Bennett JM, Reeves G, Billman GE, Sturmberg JP. Inflammation-nature’s way to efficiently respond to all types of challenges: implications for understanding and managing “the epidemic” of chronic diseases. Front Med. 2018;5:316.

Gil A, Marıa Aguilera, Gil-Campos, Canete. Altered signalling and gene expression associated with the immune system and the inflammatory response in obesity. Br J Nutr. 2007;98:121-126.
Table 1. Patient and Hospital Characteristics Stratified by BMI. Table 2. Multivariate-adjusted factors associated with hospital length of stay. Table 3. Multivariate-adjusted factors associated with perioperative complications.