Bulging after DIEP Breast Reconstruction: New Insights Concerning Rectus Diastasis and Medial Perforator Harvest

Background: The aim of this study was to evaluate the association between flap harvest technique and occurrence of abdominal bulging. Methods: A retrospective analysis of 159 patients undergoing DIEP flap breast reconstruction between 2014 and 2021 in the University Medical Center Utrecht was conducted. Outcomes measured were preoperative rectus diastasis, flap weight, laterality of flap harvest (unilateral or bilateral), timing of the harvest (immediate or delayed), number of perforators harvested (single or multiple), and location of the harvested perforator (medial, lateral, or both). Results: In 159 patients, 244 DIEP flaps were performed, 16 of these donor-sites (6.6%) developed a clinically evident abdominal bulge. When preoperative rectus abdominis diastasis was found (n = 97), postoperative bulging occurred significantly more often (P < 0.01). Patients in whom the medial perforator artery was harvested for reconstruction (n = 114) showed less abdominal bulging than patients in whom the lateral (n = 92) was harvested (P = 0.02). Using single versus multiple perforators for the DIEP flap, bilateral versus unilateral reconstruction or timing of the operation showed no significant difference in outcome of bulging (P = 1.00, P = 0.78, P = 0.59, respectively). Conclusions: The incidence of bulging in our study cohort is comparable to the literature. Harvesting the medial perforator artery for the DIEP flap showed less abdominal bulging than using the lateral perforator artery in a DIEP flap breast reconstruction. Also, preoperative rectus diastasis was found to be an important risk factor for the occurrence of bulging.