Impact of Rectus Muscle Injury during Perforator Dissection on Functional Donor Morbidity after Deep Inferior Epigastric Perforator Flap Breast Reconstruction

This study aimed to assess the extent of rectus muscle damage in deep inferior epigastric perforator (DIEP) flap harvest and to evaluate its association with functional donor morbidity. METHODS: A prospective cohort of 76 patients who underwent DIEP flap breast reconstruction was evaluated preoperatively and followed up for 1 year. Abdominal wall strength was assessed using the upper and lower rectus abdominis manual muscle function tests. Functional weakness was defined as a postoperative decrease in function by at least 2 scores. The effects of patient- and operation-related characteristics on adverse outcomes were also assessed. RESULTS: The mean width of the transected rectus muscle was 2.2 cm (partial thickness, 1.8 cm; full thickness, 0.4 cm). The mean width ratio of the overall injured muscle to the entire bilateral muscle was 0.18. Muscle injury was more severe in the cases with bipedicled flap elevation and in those with 4 or more perforators harvested. Functional weakness was detected in 13 patients (17.1%). Multivariate analyses demonstrated that the width ratio of the muscle injury was an independent predictor of functional weakness. The width ratio achieved maximal discrimination regarding the rate of functional weakness at a threshold value of 0.12, indicating that functional weakness did not develop in all 19 cases with a width ratio of <0.12. CONCLUSIONS: The extent of rectus muscle injury during perforator dissection may be associated with functional donor morbidity after DIEP flap harvest. This may be beneficial in achieving proper balance between securing flap perfusion and preserving donor functions.