Retrorectus Polyglactin Mesh Reduces the Risk of Bulge in DIEP Flap Donor Sites: A Propensity Score-Matched Study with Hernia Risk Modeling.

[INTRODUCTION] Hernia and bulge are recognized complications after DIEP flap harvest. We evaluate retrorectus placement of absorbable polyglactin mesh as a low-cost strategy to reduce hernia and bulge, and introduce a sliding scale estimator for individualized hernia risk with and without mesh use.

[METHODS] We conducted a retrospective, single-center cohort study of patients who underwent DIEP flap breast reconstruction from March 2018 to September 2023. Donor-site outcomes, including hernia and bulge, were compared between patients with and without retrorectus polyglactin mesh placement. Propensity score matching and multivariable logistic regression were used to adjust for baseline differences and identify predictors of hernia and bulge. To individualize hernia risk assessment, we developed and validated a sliding scale estimator.

[RESULTS] Among 330 patients undergoing DIEP flap reconstruction, 108 (33%) received retrorectus polyglactin mesh. After propensity score matching, polyglactin mesh placement was associated with significantly lower postoperative bulge (1.2% vs. 9.3%, p=0.017). Multivariable analysis identified age, lateral perforator harvest, and number of medial perforators as independent predictors of hernia while polyglactin mesh placement was the only significant predictor of reduced bulge risk. A logistic regression model with Lasso regularization (AUC = 0.97) was used to develop a nomogram estimating individualized hernia risk with and without polyglactin mesh.

[CONCLUSION] Retrorectus polyglactin mesh reduces bulge after DIEP flap harvest, while hernia risk is driven by age, prior open surgery, and perforator dissection. When retrorectus polyglactin mesh is used to reduce donor site morbidity, our validated nomogram can aid in estimating personalized risk and guiding surgical decision-making.