The effect of muscle defect size on donor site hernia and bulge after transverse rectus abdominis flap

Muscle sparing-transverse rectus abdominis flap has been widely used for breast reconstruction and the abdominal hernia or bulging at the donor site is relatively common complication. Previous studies have emphasized the fascial defects and the defect of muscle has been neglected. This study aims to investigate the relationship between the size of the rectus abdominis muscle defect and its impact on hernia or bulge formation after muscle sparing-transverse rectus abdominis flap.

A retrospective study of patients undergoing unilateral or bilateral breast reconstruction with muscle sparing-transverse rectus abdominis myocutaneous flap was performed. We compared the patient group with postoperative abdominal hernia or bulging requiring surgery with the patient group without hernia. The surgical specific data of the size of rectus abdominis muscle defect, muscle sparing type and flap weight are analyzed.  Results: We conducted a survey on a total of 160 patients, of which six patients experienced abdominal hernia or bulging requiring surgery. Comparing patient group requiring surgical treatment for hernia or bulging with patient group without hernia, there was a significant difference of the width of rectus abdominis muscle defect. The cut-off value of the width was 4.5 cm.  Conclusion: When performing MS-TRAM, minimizing the resection of rectus abdominis muscle remains crucial, especially the horizontal width.