DIEP-MDS for Risk Stratification of Flap Vascular Compromise and Failure in Breast Reconstruction

This multicenter retrospective observational study will develop and validate a CTA-based quantitative risk score-the DIEP Morphological Deviation Score (DIEP-MDS)-to estimate the risk of flap-related vascular compromise and flap failure in patients undergoing DIEP flap breast reconstruction. The score will quantify the extent to which an individual's perforator anatomy deviates from normative anatomic distributions derived from a reference population of individuals without breast cancer or reconstructive surgery. Specifically, a cohort of randomly selected individuals with available CTA imaging will be used to establish population-level reference distributions for key anatomic features relevant to DIEP perforator morphology, including length, diameter, and muscle thickness. The study will determine whether greater deviation in DIEP morphology, as quantified by the DIEP-MDS, is associated with an increased risk of flap-related vascular compromise and flap failure. The score will be evaluated in an internal surgical cohort and externally validated in an independent multicenter surgical cohort. In addition, the study will pre-specify an analysis to assess whether a dual-pedicle strategy is associated with a lower risk of flap-related vascular compromise compared with a single-pedicle strategy across DIEP-MDS risk strata.