Free Flap Breast Reconstruction in Cancer Patients: Effect of BMI on Outcomes of the Deep Inferior Epigastric Perforator (DIEP) Flap

BACKGROUND: The Deep Inferior Epigastric (DIEP) flap has achieved marked acceptance in free flap breast reconstruction, yet the effect of body mass index (BMI) on the procedural outcome can vary depending on the literature. This study aims to evaluate the effect of BMI on flap and donor-site complications in patients undergoing DIEP flap reconstruction. METHODS: A retrospective analysis of 233 DIEP flaps in 135 patients was performed, and the patients were stratified as three groups based on BMI: Normal (BMI<25), Overweight (BMI 25-29.9), and Obese (BMI>30). Data with regard to age, smoking history, comorbid conditions, preoperative radiation, preoperative chemotherapy, and complications post-DIEP flap reconstruction at the flap and donor-sites was analyzed and compared among groups. RESULTS: Overweight patients had statistically higher rates of overall complications (p=0.001), umbilical wound (p=0.03), and return visits to the operating room during same hospital stay (p=0.004) compared to normal weight patients. Obese patients experienced statistically higher rates of overall complications (p=0.000023), return visits to operating room during same hospital stay (p=0.02), abdominal necrosis (p=0.0008), breast wound (p=0.019), umbilical wound (p=0.0053), and vacuum-assisted closure wound therapy (p=0.0006) compared to normal weight patients. There were no significant differences between the groups in regards to infection of the abdominal, breast, and umbilical sites, abdominal wound, abdominal seroma, breast necrosis, breast seroma, breast hematoma, umbilical necrosis, blood transfusion, pulmonary embolism, average OR time, average hospital length of stay, or loss of flap viability (p>0.05). Age distribution and preoperative radiation were not statistically different. Compared to normal-weight patients, overweight patients had significantly lower rates of smoking history and higher rates of hypertension, diabetes, and preoperative chemotherapy. Obese patients had statistically higher rates of preoperative chemotherapy compared to normal weight patients. These confounding factors between the groups are a limitation to the BMI control. CONCLUSION: Overweight and obese patients undergoing DIEP flap breast reconstruction are predisposed to statistically higher risk for the aforementioned complications than normal weight patients. However, there was no significant difference in loss of flap viability between the groups. Therefore, DIEP flap breast reconstruction is an appropriate option.