Muscle-sparing TRAM flap does not protect breast reconstruction from postmastectomy radiation damage compared with the DIEP flap

BACKGROUND: Irradiation to free flaps following immediate breast reconstruction has been shown to compromise outcomes. The authors hypothesized that irradiated muscle-sparing free transverse rectus abdominis musculocutaneous (TRAM) flaps experience less fat necrosis than irradiated deep inferior epigastric perforator (DIEP) flaps. METHODS: The authors performed a retrospective study of all consecutive patients undergoing immediate, autologous, abdomen-based free flap breast reconstruction with muscle-sparing free TRAM or DIEP flaps over a 10-year period at their institution. Irradiated flaps (external-beam radiation therapy) after immediate breast reconstruction were compared with nonirradiated flaps. Logistic regression analysis identified potential associations between patient, tumor, and reconstructive characteristics and surgical outcomes. RESULTS: The analysis included 625 flaps: 40 (6.4 percent) irradiated versus 585 (93.6 percent) nonirradiated. Mean follow-up for the irradiated and nonirradiated flaps was 60.0 and 48.5 months, respectively (p = 0.02). Overall complication rates were similar for both the irradiated and nonirradiated flaps. Irradiated flaps (i.e., both DIEP and muscle-sparing free TRAM flaps) developed fat necrosis at a significantly higher rate (22.5 percent) than the nonirradiated flaps (9.2 percent; p = 0.009). There were no differences in fat necrosis rates between the DIEP and muscle-sparing free TRAM flaps in both the irradiated and nonirradiated groups. CONCLUSIONS: Both DIEP and muscle-sparing free TRAM flap reconstructions had much higher rates of fat necrosis when irradiated. Contrary to our hypothesis, the authors found that immediate breast reconstruction with a muscle-sparing free TRAM flap does not result in a lower rate of fat necrosis than reconstruction with a DIEP flap.