P15. Another Look at the Medial and Lateral Rows: 18 Month Follow-up in Over 200 DIEP Flaps

PURPOSE: The optimal choice between medial and lateral row perforators for deep inferior epigastric artery perforator (DIEP) flaps remains contested; the medial row has been associated with lower abdominal wall morbidity, and the lateral row with lower rates of fat necrosis. While many comparative studies exist, few report follow-up over 12 months. As these morbidities can take well over a year to declare themselves, we aim to investigate our institution's long-term outcomes. METHODS: We performed a retrospective review of patients who underwent mastectomy followed by DIEP reconstruction between November 2004-December 2021 with over 18 months follow-up. Post-operative outcomes were compared between flaps supplied by the medial row only, lateral row only, and a combination of both rows. RESULTS: A total of 226 flaps were included: 172 lateral, 29 medial, and 25 combined. Obesity (BMI>30) was more prevalent in the lateral group (lateral: 50%, medial: 26%, combined: 26%, p=0.05), as was mesh use (lateral: 77%, medial: 47%, combined: 53%, p=<0.01). The rate of clinical fat necrosis was significantly higher in the medial group when controlling for obesity (medial: 31%, lateral: 9%, combined: 16%), p=0.04). We found no correlation with the number of perforators used. There were no significant differences in rates of hernia or bulge when controlling for obesity and mesh use (lateral: 10%, medial: 16%, combined:11%, p=0.54). CONCLUSION: Our long-term follow-up suggests that perforator selection may not be associated with abdominal wall morbidity, but confirms previous studies' findings that lateral row perforators yield the lowest rates of fat necrosis.