British Journal of Plastic Surgery (1982) 35,443451 0 1982 The Trustees of British Association of Plastic Surgeons
0007- 1226/82/0406-0443 $02.00
Soft tissue reconstruction of the breast using an external oblique myocutaneous abdominal flap
DONALD R. MARSHALL, E. JOHN ANSTEE and MURRAY J. STAPLETON
Victorian Plastic Surgery Unit, Melbourne, Australia
Summary-A method of breast reconstruction is described in which the soft tissue usually discarded in an abdominal Iipectomy is transferred into the breast as a myocutaneous flap based on the external oblique muscle. The anatomy of the flap is described and two cases are presented. No prosthesis is required.
The latissimus dorsi myocutaneous flap is now used widely to provide skin and muscle cover in post-mastectomy breast reconstruction (Maxwell et al., 1980), but a prosthesis is necessary to provide sufficient breast volume. The opposite breast is occasionally available in breast reconstruction as a donor of soft tissue, providing it is large enough and certain pathological criteria are satisfied (Marshall et al., 1981). The skin and fat of the lower abdomen also provides an occasional source of soft tissue for breast reconstruction and can be transferred in a two-stage flap procedure (Marshall et al., 1981), or as a single-staged micro-vascular repair (Holstrbm, 1979).
While each of these methods of transferring tissue from the lower abdomen is occasionally indicated, the practical difficulties rule them out for routine use. Our experience with the latissimus dorsi flap combined with a prosthesis has been that while the early results are excellent, there are a sufficient number of capsular contractions to make the late results of a soft tissue repair alone superior overall. This conviction has prompted us to continue the search for a simple method of transferring the skin and fat of the lower abdomen normally discarded in an abdominal lipectomy to the breast, as many mastectomy patients have adequate soft tissue for this procedure. Furthermore, the fat of the lower abdominal wall is contained in large discrete compartments and bears an excellent likeness to breast tissue.
While the two-stage flap operation already described produces a satisfactory end result, the large area of temporary skin graft is prone to bacterial colonisation, which, with the present problem of antibiotic-resistant hospital staphylo- cocci, poses major nursing problems.
With the current renewed interest in the anatomy of the skin circulation and the role of the sub- fascial vessels, it seems logical to explore the possibility of carrying this soft tissue to the breast on a muscle flap to achieve the same end result without the raw area: the question is which muscle?
To enable the abdominal skin and fat flap to be transferred to the breast, it is clear that the vascular pedicle has to come from above and the superior epigastric vascular leash appears a possibility. However, the lower portion of the rectus abdominus muscle lies directly beneath the required skin flap and cannot be sacrificed with- out weakening the lower abdominal wall in a way which seems unacceptable, as in this region there is no posterior rectus sheath.
The only other abdominal muscle which seems a possible carrier for flap transfer is the external oblique, running as it does from the rib cage laterally to the mid-line of the abdomen, anterior to the rectus abdominus and beneath the skin flap (Fig. I).
Anatomical basis of the operation
The segmental intercostal vessels pass forward into the abdomen between the internal oblique and the transversus muscles as far as the rectus sheath (Fig. 2), but their lateral cutaneous branches pass through the internal oblique in the mid-lateral line to pass forward deep to the external oblique to supply the skin and fat of the abdominal wall (Fig. 3).
Cadaver dissections reveal the technical feasi- bility of carrying the skin and subcutaneous tissue of the lower abdomen into the breasts via
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Fig. 1 Line drawing to show: 1. On the left side of the patient the skin flap outlined in a solid black line and the underlying muscle flap outlined in a dotted line. 2. On the right side of the patient the myocutaneous flap with an island of skin and fat transferred superiorly into the region of the breast (skin tunnel not shown). Note the deficiency in the external oblique muscle with the underlying ftbres of internal oblique running as far as the lateral edge of the rectus sheath and the vertical rectus abdominus muscle medial to this.
Fig. 2 Drawing of a transverse section of the left side of the abdominal wall. Note the external oblique, internal oblique, transverse abdominus and the fascial arrangement of the rectus sheath. The segmental nerves and vessels and their mid-lateral branches are shown as a broken line. The plane of the elevation of the myocutaneous flap is shown as a dotted line and passes as far posteriorly as the lateral branches.
Fig. 3 Drawing of a transverse section of the abdominal wall with the flap now elevated. Note that the rectus abdominus muscle is undisturbed. The skin and fat overlying the external oblique muscle is raised as an island.
a subcutaneous tunnel lying over the ribs, using such an external oblique myocutaneous flap.
The circulatory competence of the flap can be established during the course of a number of routine abdominal lipectomies, in which the skin and fat is left as an island attached to the muscle flap, which is temporarily developed up to the rib cage. It is later replaced, the skin excised and the lipectomy completed in the usual way. The defect in the external oblique muscle seems unlikely to cause a problem, providing the underlying muscles are in no way damaged.
The patient had a right Patey mastectomy for carcinoma of the breast two years prior to consultation (Fig. 4). She had a moderate ab- dominal apron and wished to have a breast reconstruction as well as an abdominal lipec- tomy. It was decided to reconstruct her breast using the tissue which would otherwise be dis- carded in the abdominal lipectomy. The skin defect in the breast was minimal (Figs. 5 and 6). She had had an abdominal operation via a lower midline incision seven years ago. With the patient lying on her back on the operating table, the skin flap was outlined on the right side from umbi- licus to pubis in the midline and extending as a triangle to the anterior superior ilial spine (Fig. 7).
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Fig. 4 Pre-operative photograph showing the transverse scar Fig. 5 Photograph of same patient showing the dependent of a right Patey mastectomy two years before. normal left breast.
Fig. 6 Photograph of same patient showing absence of Fig. 7 Photograph taken on the operating table showing the contour of the right side although there is no shortage of island flap of skin and fat (solid line) and the underlying skin, muscle flap (dotted line). The planned position of the sub-
mammary groove is also shown.
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The incision was deepened through the freed from the iliac crest and the posterior free external oblique aponeurosis and the anterior border of the muscle was transected. The lateral rectus sheath was elevated in continuity. The skin perforating vessels were identified and preserved and fat usually discarded was left attached to the in two spaces as the muscle was elevated from external oblique muscle (Fig. 8). A strip of the lateral surface of the ribs (Fig. 10). The external oblique four inches wide was elevated abdominal skin above the island flap was from the underlying internal oblique muscle back elevated from the abdominal wall to above the as far as the rib cage (Fig. 9). The muscle was umbilicus on each side, as in a normal lipectomy.
Fig. 8 Photograph showing the island of skin and fat which is left attached to the underlying external oblique muscle and the anterior rectus sheath.
Fig. 9 Photograph showing the upper skin flap elevated off the external oblique muscle to above the umbilicus as in an abdominal lipectomy. The strip of external oblique which is left in continuity with the island of skin and fat is also visible.
Fig. 10 Photograph showing the strip of external oblique muscle with the lowest lateral cutaneous branch of the intercostal vessels passing from internal oblique into the overlying muscle.
The mastectomy scar in the breast was opened and the skin flaps raised from the pectoralis major muscle. A subcutaneous tunnel was es- tablished from the breast to the abdominal wound and the myocutaneous flap was then passed through this into the breast (Fig. 11). No skin replacement was necessary in this case so most of the skin of the flap was removed to leave an island of skin as a monitor of the circulation of the flap (Fig. 12). The remainder of the flap was then arranged to conform as accurately as possible to the normal breast. No prosthesis was used and the shape and volume of the recon- structed breast was sufficiently close to the normal side that no adjustment to the latter was required (Fig. 13).
The abdominal lipectomy was then com- pleted with a transposition of the umbilicus and excision of the skin and fat on the opposite side. The wounds were closed with drainage and the circulation in the flap appeared adequate at all times. A nipple reconstruction was not per- formed. The operating time was approximately two hours and the blood loss was 500mls.
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Fig. 11 Photograph showing the subcutaneous tunnel from the wound in the breast into the abdominal wound. Note the gloved hand emerging from