Use of External Oblique Musculocutaneous Flap
In Closure of large defect after Mastectomy
Oliver S Leyson, MD
Mario Guevarra, MD, FPCS
Reynaldo O. Joson MD, FPCS
_____________________________________
Reprint requests: Mario Guevarra MD FPCS, Department of Surgery, Hospital X, Quirino Avenue,Malate, Manila, Philippines.
Abstract
Background: Primary closure of a large defect after mastectomies of patients with locally advanced breast cancers posed a great challenge among surgeons. Objectives: To described the use of external oblique muscle flap (EOMF) to close defect after mastectomies of locally advanced cancers. Results: Eight patients were operated consecutively from February 2002 to August 2004
in our institution. Mean age of the patient was 43.7 with a (range of 33-52). All patients had underwent modified radical mastectomy under general anesthesia. Average tumor size is 9.1 cm with a range of 5-13 cm. Four patients had skin ulcerations 5-6 cm in diameter. The average size of the defect was 17.25 x 14.25 cm with a range of 23x18 to 15x13 cm. Closure of mastectomy defect was achieved using the EOMF in all patients with primary closure of the donor site. A
complication developed in one patient consisting of a flap tip necrosis which was managed conservatively. Two patients developed recurrence at the incision site within the year after follow up and were excised under general anesthesia. We believe that the EOMF should be considered safe and reliable option in closing large defects after mastectomy of locally advanced breast carcinomas.
Key Words: Breast cancer; external oblique musculocutaneous flap
External Oblique Musculocutaneous Flap
Introduction
Locally advanced breast cancer (T4 lesions) when extirpated commonly presents problems as far as wound closure is concerned. Skin graft, relaxing incision with undermining the wound edges, fasciocutaneous flap and myocutaneous flap are the techniques presently used. Decreasing the tumor size by neoadjuvant chemotherapy or radiation are options which can be done to facilitate closure of the defect primarily. There are few reports on the use of exernal oblique musculocutaneous flap in closing a huge defect after mastectomy for locally advanced cancers.
Objectives:
The objective of this paper was to describe an experience with the external oblique myocutaneous flap (EOMF) as an alternative option in covering large wound defect after mastectomy of locally advanced breast carcinoma(T4 lesions).
Methods:
All records of patients with locally advanced breast cancer (T4 lesion) in which an EOMF was done from February 2002 to August 2004 in Hospital X were reviewed as to tumor characteristics, post-extirpation tumor size and outcome of reconstruction.
A triangular flap was made at the epigastric area with the tip starting at the midline (linea alba) between the xiphoid and umbilicus. The flap was elevated with the anterior rectus sheath underneath and extended laterally to the external oblique aponeurosis and muscle (Figure II).
The blood supply coming from the multiple perforators in the internal oblique muscle can be ligated without compromising the viability of the flap. The degree of mobilization can be reached up to the clavicle (Figure I-B). The secondary defect “dog –ear”, from the axilla and lumbar area can be excised. The flap at the umbilicus and xiphoid are approximated to close the donor site. The EOMF was anchored at the pectoralis major muscle with the anterior rectus fascia using Vicryl 2.0 thereby stabilizing the flap. The dermal layers are approximated with Vicryl 3.0 and the skin was closed with Nylon 4.0. Two tube suction drains are placed at the axilla and underneath the flap.
See figure 1-5 for illustrations.
Results
A total 8 patients were done during the stated period. The mean age of the patients was 43.7 years with a range of 33-52. All patients underwent modified radical mastectomy under general anesthesia. Table 1 shows the details of the patients and tumor characteristics. Average tumor size was 9.1 cm (range 5-13 cm). Average size of the wound defect was 17.25 x 14.25 with range of 23x18 to 6x10. Skin ulceration was present in 3 patients. Complication developed in one patient, a necrosis at the tip of the flap and was managed conservatively without necessitating a skin graft. Two patient developed tumor recurrence at the incision site within the year, managed by radiation and chemotherapy.
Discussion:
The external oblique musculocutaneous flap was first used by Lesnick and Davids (1) for the closure of lower abdominal defects in early 1950’s. In 1964 Hershey and Butcher (2) used theEOMF for closure of the upper abdominal and chest wall defects. In the 1980’s Hodgkin’s and Arnold (3) of the Mayo Clinic reported using EOMF to cover defect after resection of sternum and
ribs due to radio necrosis and recurrent Hodgkin’s disease.
The use of EOMF for breast reconstruction was reported by Holle and Pierini (4) in 1983. They performed cadaver dissection to show its blood supply. They said that the ascular supply of the muscle was from the branches of the intercostals and lumbar arteries. The branches emerging from the 5th to 6th intercostals arteries were of considerable size and branches of the intercostals nerves innervate the muscle.
The use of EOMF for wound closure after mastectomy for primary and recurrent breast tumor was reported by Bogossian et al, of the Memorial Sloan-Kettering Cancer Center in 1994 (3). They were successful in using the EOMF in 20 consecutive cases of breast cancer patients. They opened that the EOMF was an excellent choice of coverage of large ipsilateral chest wall defect
because of the following reasons:
1. The external oblique myocutaneous flap was a sturdy, sensate myocutaneous flap with a good blood supply usually shielded from the radiation port, a possible advantage over the latissimus dorsi flap.
2. It does not violate other flap territories.
3. There was no need to reposition the patient on the operating table for harvesting of the flap.
4. The external oblique myocutaneous flap was an easy and quick flap to raise.
5. The flap has good quality skin with ideal thickness in most patients, resulting in an even contour.
6. There was no donor size morbidity and no need for skin grafting of the abdomen.
7. There was an absence of abdominal-wall weakness with the rectus abdominis muscles remaining intact.
8. This flap was suitable for further breast reconstruction with implants.
The external oblique muscle (EOM) was the largest and strongest of all flat abdominal muscles. It was located in the anterolateral portion of the abdominal wall. Its origin was the external surfaces of ribs 5-12 and its insertion was the linea alba, pubic tubercle, and the anterior half of the iliac crest. Its innervations were from the inferior 6 thoracic nerves, including the sub costal. The blood supply primarily involves the small arteries that arise from anterior and collateral branches of the posterior intercostals arteries in the 10th and 11th intercostals spaces and from anterior branches of the subcostal arteries. (2) Perforators enter the undersurface of the muscle close to the posterior axillary line. Since these vessels interdigitate throughout the muscle, flap viability was
secured if one or more of these perforators are divided inadvertently while raising the flap. The external oblique aponeurosis becomes the anterior rectus fascia and the posterior rectus fascia was composed of the transversalis fascia arc, and the internal oblique fascia. Below the umbilicus at the arcuate line, the posterior rectus fascia was absent. The blood supply was the perforating branches coming from the intercostals arteries and the superficial circumflex iliac arteries. The
presence of the posterior rectus fascia and the muscle maintains the integrity of the epigastric area thereby a mesh was not necessary during closure of the donor site. The secondary defect in the epigastric area and at the lumbar area can be covered by extending the incision and advancing the
loose flap and removing the “dog-ear.”
The external oblique myocutaneous flap offers a well-perfused composite tissue for reconstruction. It was capable of reaching the third ipsilateral rib space superiorly and up to 5 cm beyond the midlines, depending on the laxity of skin over the anterior abdominal wall. With the experience in 8 patients reinforce by the experience of other surgeons. The authors believe that the EOMF should be considered as a safe reliable option in closing primarily large defects after mastectomy of locally advance breast carcinoma.
References
1. Lesnick, GJ, Davids, AM. Repair of surgical abdominal wall defect with a pedicled musculofascial flap. Ann. Surg.1953; 137:569.
2. Hershey, F, Butcher H. Jr. Repair of Defects after partial resection of abdominal wall. Am J.Surg. 1964; 107:586.
3. Bogossian N, Chaglassian T, Rosenberg PH, Moore MP. External oblique myocutaneous flap coverage of large chest-wall defects following resection of breast tumors. Plast Reconstr Surg.1996; 97(1):97-103.
4. Holle,J., Pierini, A. Breast Reconstruction with an External Oblique Abdominis Muscle Turnover Flap and a Bipedicle Abdominal Skin Flap. Plast. Reconstr.Surg. 1983; 469-473.
Design of flap (Figure 1 )
Table 1: Eight cases of mastectomies operated at OMMC from February 2002 to
Figure 2. Pre-extirpative status.
Figure 3. Post operative defect.
Figure 4. Harvesting of EOMF.
Figure 5. Transportation of EOMF.
Figure 6. Closure of defect.
