Operative management of abdominal bulge following deep inferior epigastric perforator flap breast reconstruction: a systematic review of repair strategies and outcomes.

Background: Abdominal bulge after deep inferior epigastric perforator (DIEP) flap breast reconstruction is an uncommon but clinically meaningful donor-site complication. Although several operative repair strategies have been described, evidence guiding management remains limited. This systematic review aimed to synthesize the evidence on operative management of established abdominal bulge after DIEP flap breast reconstruction, including repair techniques, outcomes, and persistent or recurrent deformity. Methods: This review was prospectively registered (PROSPERO CRD420261368586). MEDLINE, Scopus, and Web of Science were searched from inception to August 2026 for studies reporting abdominal wall morbidity after DIEP flap breast reconstruction and describing management of an established complication with extractable outcomes. Quality was appraised with Joanna Briggs Institute tools and certainty of evidence with GRADE. Heterogeneity in design, definitions, techniques, and outcome reporting precluded meta-analysis, so findings were synthesized narratively. Results: Six studies were included: five retrospective single-arm series and one case report, with no randomized, prospective comparative or controlled study identified. Clinically relevant bulge or hernia occurred in 3.6% to 4.8% of patients in cohorts reporting denominators. Repair outcomes were extractable for 34 patients across five studies, spanning DIEP-specific and mixed abdominal free-flap populations. Reported techniques were open fascial plication with onlay mesh, laparoscopic underlay, robotic retromuscular, and enhanced-view totally extraperitoneal repair. Persistent or recurrent deformity followed both open and minimally invasive approaches. Certainty was very low for every outcome assessed, and no study used a validated post-repair patient-reported outcome measure, objective abdominal wall function testing, or imaging-confirmed durability assessment. Conclusions: Operative management of post-DIEP abdominal bulge is poorly standardized, and very low certainty evidence does not establish superiority of any technique, mesh type, or mesh plane. We propose a phenotype-based classification, a structured assessment pathway, and a minimum reporting dataset for secondary repair, offered as expert interpretation requiring prospective validation rather than as guidance. Future studies should use standardized phenotyping, repair-specific follow-up, cross-sectional or dynamic imaging, objective function testing, and validated patient-reported outcomes.