The External Oblique Flap for Reconstruction of the Rectus Sheath

Despite the availability of synthetic materials and distant fascial flaps, primary closure of ventral abdominal defects with contiguous tissues remains the preferred solution. Increased experience with such defects in the lower abdomen, particularly at the time of bilateral rectus muscle transposition, led in 1985 to the investigation of an external oblique abdominis flap for closure of the anterior rectus sheath. From October of 1985 to October of 1990, 33 patients underwent repair of bilateral lower rectus abdominis defects with the help of bilateral external oblique flaps. Each of the patients had undergone synchronous chest or breast reconstruction using a transverse rectus abdominis musculocutaneous flap including bilateral rectus muscle pedicles. Although all patients in this study had undergone double-pedicle rectus muscle procedures, not all patients having had double-pedicle rectus muscle procedures required this maneuver. External oblique flaps were performed at the time of rectus sheath repair only if fascia could not be approximated without tearing. After closure of the bilateral paramedian defect, synthetic mesh overlay was added only if the direct closure still appeared excessively tight. At the time of advancement of the external oblique muscle and fascia, the internal oblique abdominis muscle and lateral cutaneous nerve of the thigh were preserved. Of the 33 patients who underwent this procedure, 7 required the addition of mesh overlay. Thirty-two patients healed uneventfully with a remarkably solid ventral abdominal wall. One patient developed an early postoperative hernia subsequent to a major and prolonged abdominal-wall infection and abscess. Patient follow-up ranged from 1 to 36 months, with a mean of 12 months. In light of this experience in 33 patients with up to 3 years of follow-up, it is clear that the external oblique abdominis muscle should be considered as a flap for repair of ventral abdominal defects with a high likelihood of success and without demonstrable donor-site disability. Although the external oblique abdominis muscle unit has been described previously for both regional and distant use, donor-site morbidity remained a nagging concern that now may be answered more confidently. Its effectiveness in closing the anterior rectus sheath should encourage its use in the closure of other difficult defects of the ventral abdominal wall. (Plast. Reconstr. Surg. 90: 608, 1992.)