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

Reconstruction with autologous tissue remains a sound option for many women following mastectomy.1,2 Among the strengths of autologous reconstruction is achievement of a natural consistency and pleasing aesthetic outcome. However, the main limitation can be donor site morbidity following flap harvest.3 Modifications in surgical technique and flap design using the muscle-sparing transverse rectus abdominus myocutaneous (MS-TRAM) flap and the deep inferior epigastric perforator (DIEP) flap have decreased donor site morbidity.4–8 However, advancements in preserving the integrity of the rectus muscle in the abdominal wall, that is, by focusing on single perforator dissection, may result in compromised flap vascularity and an increase in perfusion-related flap complications.5,9 Fat necrosis is a consequence of either inadequate arterial inflow or relatively poor venous outflow in a DIEP flap. Development of fat necrosis requiring reoperation can result in significant aesthetic deformity and emotional and financial costs: treatment often requires breast imaging studies, tissue biopsy, and/or excision and may cause significant anxiety in patients with a history of breast cancer. Rates of fat necrosis documented in the literature range widely, from 2% to 62.5%.4,5,9–12 The roles of flap type, perforator number, donor site location, and flap size on the development of fat necrosis and complications continue to be debated in the literature. To our knowledge, no previous study has analyzed the interaction of perforator number and flap weight and their combined effect on fat necrosis in breast reconstruction with abdominal perforator-based free flaps. We hypothesized that increasing flap weight results in increased risk of fat necrosis. We also hypothesized that flaps with larger weights require more perforators to optimize vascular perfusion and that inclusion of more than one perforator may protect larger flaps from fat necrosis. Therefore, we retrospectively reviewed our patients to investigate the associations between flap weight and number of perforators with rates of fat necrosis and other associated complications in DIEP and MS-TRAM free flaps.