126 Augmented venous drainage using the superficial inferior epigastric vein (SIEV) is a protective factor against postoperative fat necrosis in autologous free flap breast reconstruction: A retrospective cohort study

Abstract Background Autologous abdominally-based free flaps, such as the deep inferior epigastric perforator flap, are commonly employed to reconstruct the breast following mastectomy. Postoperative fat necrosis of the flap significantly detriments cosmetic outcomes and patient satisfaction. Anastomosis of the flap superficial inferior epigastric vein (SIEV) to a recipient-site vessel may reduce fat necrosis by supplying additional venous drainage, though evidence in the current literature has remained insufficient to substantiate its protective effect. Methods A retrospective analysis was conducted of patients who underwent elective unilateral abdominally-based free flap breast reconstruction from 2012 to 2022 at a tertiary centre in London, United Kingdom. Patients were divided into two groups based on whether the SIEV was utilised as a secondary venous outflow, and the one-year incidence of clinical fat necrosis was compared. Statistical analyses included Fisher's exact test and logistic regression with univariable and multivariable models. Results The final cohort contained 243 patients (243 flaps). Of these, 56.0% had the superficial system connected. The incidence of fat necrosis in the SIEV group was significantly lower than in the non-SIEV group (13.2% versus 29.0%, respectively, p=0.003), and SIEV use remained a protective factor against fat necrosis after adjustment for potential confounding variables (odds ratio: 0.43; 95% CI: 0.22, 0.85; p=0.015). Conclusions Based on this cohort, we recommend recruitment of the superficial venous system in abdominally-based free flaps for breast reconstruction as prophylaxis against postoperative fat necrosis. Further multi-centre prospective studies are warranted to validate these findings and better inform surgical practice.