Perforator number predicts fat necrosis in a prospective analysis of breast reconstruction with free TRAM, DIEP, and SIEA flaps

Background: Breast reconstruction using flaps from the lower abdomen can be compromised by fat necrosis. The muscle-sparing free transverse rectus abdominis musculocutaneous (TRAM), deep inferior epigastric perforator (DIEP), and superficial inferior epigastric artery (SIEA) flaps are techniques that have evolved in an effort to decrease abdominal donor-site morbidity. Each flap in this evolution, however, includes fewer perforating blood vessels. The authors hypothesized that flaps with fewer perforators are less well perfused and therefore more likely to suffer fat necrosis. Methods: The authors prospectively studied the incidence of fat necrosis and number of perforators in 228 consecutive abdominal free flap breast reconstructions. Results: The incidence of fat necrosis was 14, 25, 5, and 19 percent for SIEA flaps and flaps with one to two, three to five, and more than five perforators, respectively. The incidence of fat necrosis was significantly associated with the number of perforators (p = 0.007), smoking (p = 0.02), and inclusion of zone 3 of flaps (p = 0.05). The lowest risk of fat necrosis occurs in flaps with three to five perforators, which are predominantly muscle-sparing TRAM flaps. The risk of fat necrosis is highest in flaps with one or two perforators, which are predominantly DIEP flaps. SIEA flaps, and flaps with poor perforators in which greater than five perforators were included, had an intermediate risk of fat necrosis. Conclusions: The risk of fat necrosis in breasts reconstructed with free muscle-sparing TRAM, DIEP, and SIEA flaps increases as the number of perforators supplying the flap decreases. Breast reconstruction using DIEP and SIEA flaps may decrease abdominal donor-site morbidity compared with muscle-sparing TRAM flap techniques, but these flaps also carry a higher risk of fat necrosis that can compromise the breast reconstruction.