Risk factors and predictive models for fat necrosis in DIEP flap breast reconstruction: A systematic review

Background Autologous breast reconstruction is an integral component of post-mastectomy care. Despite the advantages of deep inferior epigastric perforator (DIEP) flaps, fat necrosis remains a common complication that compromises aesthetic outcomes, patient satisfaction, and reconstructive durability. This systematic review evaluates risk factors associated with fat necrosis following DIEP flap breast reconstruction to inform clinical decision-making and optimize outcomes. Methods A systematic search of PubMed, MEDLINE, Embase, Scopus, Web of Science, and the Cochrane Library was conducted in accordance with PRISMA guidelines. English-language studies between 2008 and 2025 evaluating risk factors or predictive models for fat necrosis following DIEP flap breast reconstruction were included. Risk of bias was assessed using ROBINS-I. Results Thirteen studies involving 3,609 flaps in 3,013 patients were analysed. . Fat necrosis incidence ranged from 7.5% to 59.5%. DIEP flaps were associated with higher rates of vascular compromise requiring reoperation (13% p=0.003). Use of lateral row perforators significantly reduced fat necrosis compared with medial row perforators (8.2% vs. 24.5%; p<0.001). Intraoperative indocyanine green angiography was associated with reduced fat necrosis (RR 0.49; 95% CI, 0.25–0.97; p=0.021). Higher flap weight and body mass index greater than 30 kg/m² were consistent predictors. Total flap loss was rare (<1%). Conclusions Fat necrosis remains a predominant complication following DIEP flap breast reconstruction. Optimization of patient selection, perforator strategy, and intraoperative perfusion assessment may reduce ischemic morbidity and improve reconstructive outcomes.