Increased Flap Weight and Decreased Perforator Number Predict Fat Necrosis in DIEP Breast Reconstruction

Background: Compromised perfusion in autologous breast reconstruction results in fat necrosis and flap loss. Increased flap weight with fewer perforator vessels may exacerbate imbalances in flap perfusion. We studied deep inferior epigastric perforator (DIEP) and muscle-sparing transverse rectus abdominis myocutaneous (MS-TRAM) flaps to assess this concept. Methods: Data from patients who underwent reconstruction with DIEP and/or MS-TRAM flaps between January 1, 2010 and December 31, 2011 (n = 123) were retrospectively reviewed. Patient demographics, comorbidities, intraoperative parameters, and postoperative outcomes were collected, including flap fat necrosis and donor/recipient site complications. Logistic regression analysis was used to examine effects of flap weight and perforator number on breast flap fat necrosis. Results: One hundred twenty-three patients who underwent 179 total flap reconstructions (166 DIEP, 13 MS-TRAM) were included. Mean flap weight was 658 ± 289 g; 132 (73.7%) were single perforator flaps. Thirteen flaps (7.5%) developed fat necrosis. African American patients had increased odds of fat necrosis (odds ratio, 11.58; P < 0.001). Odds of developing fat necrosis significantly increased with flap weight (odds ratio, 1.5 per 100 g increase; P < 0.001). In single perforator flaps weighing more than 1000 g, six (42.9%) developed fat necrosis, compared to 14.3% of large multiple perforator flaps. Conclusions: Flaps with increasing weight have increased risk of fat necrosis. These data suggest that inclusion of more than 1 perforator may decrease odds of fat necrosis in large flaps. Perforator flap breast reconstruction can be performed safely; however, considerations concerning race, body mass index, staging with tissue expanders, perforator number, and flap weight may optimize outcomes