Comparing BMI and Abdominal Wall Thickness as Predictors of Complications in Autologous Breast Reconstruction
Nicolas Greige, B.S., Steven M. Sultan, M.D., Amanda M. Rizzo, M.D., Katie E. Weichman, M.D..
Montefiore Medical Center, Bronx, NY, USA.
Body mass index (BMI) plays an important role in the risk stratification of patients undergoing almost all surgical procedures, including autologous breast reconstruction. BMI classifies patients based on height and weight, but does not take into account their distribution of weight. BMI is therefore an imprecise predictor of complications in abdominally-based breast reconstruction. The authors sought to determine if the thickness of a patient's abdominal wall as measured on CT scan is more predictive of donor site or flap complications in abdominally-based breast reconstruction than BMI.
Patients who underwent abdominally-based free flaps for breast reconstruction over the past six years at a single institution were reviewed. Only those with a preoperative CT scan and at least 6 months of post-operative follow up were included. Abdominal thickness was measured on CT scan at several points: in the midline between the xyphoid and the umbilicus, in the midline at the level of the anterior superior iliac spine (ASIS), at a point between the ASIS and the midline, and directly over the ASIS. The thickest overall midline point on the abdominal wall and the calculated flap volume were also included for analysis. Univariate analyses were used to determine the predictive value of each of the aforementioned points for a range of flap and donor site complications. These data were additionally compared to the predictive value of BMI.
Eighty-eight patients (130 flaps) were included for analysis. The average age and BMI of included patients was 50.7±8.6 years. The average BMI was 31.3±3.9. BMI was not predictive of donor site or flap complications. Donor site breakdown was associated with both increased thickness over the ASIS (breakdown=33.0±16.9 mm, no breakdown=25.5±14.2 mm; p=0.03) and an increase in the thickest overall midline point on the abdomen (breakdown=48.7.0±12.5 mm, no breakdown=43.6±9.8 mm; p=0.04). Increased thickness over the ASIS also predicted combined donor site complications (complication=32.6±16.7 mm, no complication=25.3±14.1 mm; p=0.03). Breast seroma and infection were associated with higher calculated flap volume (seroma=608.4±161.9 cm3, no seroma=451.8±150.4 cm3; p=0.04)(infection=568.4±167.3 cm3, no infection=450.2±149.9 cm3; p=0.05). Mastectomy flap necrosis and flap loss were not significantly associated with any point or flap volume.
Cross-sectional measurements of abdominal wall thickness, especially at the thickest midline point and at the ASIS, possess greater value and predictive potential for donor site complications than BMI in abdominally-based breast reconstruction. Flap complications, namely recipient site seroma and infection, are associated with higher calculated flap volumes.
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