Source Surgery of The Breast Principals and Art Volume: n/a Number: n/a 1999

The Gluteal Artery Perforator Flap

The use of a buttock skin and fat flap based on either the superior or inferior gluteal artery perforators (GAPs) results in a scar largely invisible to the patient, adequate harvest of autogenous tissue even in young, thin patients, and a flap with a long vascular pedicle. The GAP flaps differ from previously described superior and inferior gluteal myocutaneous flaps by eliminating the muscle component and providing a much longer vascular pedicle. In the chest, the internal mammary artery and vein are the preferred recipient vessels, although the thoracodorsal vessels also may be used. No vein grafts or rotations of external jugular or cephalic veins have been necessary.

FIG. 12. Skin island location of the superior gluteal artery perforator flap. The superior gluteal artery can be found one third the distance between the posterior superior iliac spine and the greater trochanter.

FIG. 13. Superior gluteal vessel dissection through the retracted gluteus maximus muscle.

For unilateral reconstruction, the patient is placed in the lateral decubitus position for a two-team approach. In our series of 70 cases, the superior GAP (S-GAP) flap has been used 64 times and the inferior GAP (I-GAP) flap has been used six times. There are certain advantages to using the S-GAP flap. First, it is easier to conceal the donor scar in the bathing suit line. Second, the sciatic nerve is not exposed in the dissection. Preoperatively, the superior gluteal vessels are marked according to known anatomic landmarks. This vessel enters the gluteus maximus muscle at a point approximately one third down a line drawn from the posterosuperior spine to the greater trochanter. After the Doppler probe is used to identify the perforators, a fusiform skin island is drawn over the perforators (Fig. 12). Skin island size varies from 9 X 24 to 12 X 32 cm. The incision is made down through the skin and fat to the muscle, and the skin island is elevated from lateral to medial until a larger perforator is located. Most flaps have been elevated on one perforator, although several have used two perforators that joined within the muscle or deep to the muscle. Loupe magnification and microsurgical technique are used to dissect the pedicle. The muscle is split around the perforator in the direction of its fibers. Small muscular side branches of the perforating vessels are divided as previously described in the section covering the DIEP flap. Dissection continues to the superior gluteal artery and vein deep to the muscle (Fig. 13). It is the final 2 or 3 cm of the dissection that generally present the greatest difficulty because there are often multiple branches that need to be divided. The superior gluteal artery is usually 3.5 mm in diameter and matches the internal mammary artery's diameter quite well. The vein diameter varies between 2.5 and 4.5 mm.

FIG. 14. Closure of the S-GAP flap do-nor site and insetting of the flap.

The GAP flap consists of only skin, fat, and a pedicle approximately 8 cm in length. Flap weight has ranged from 210 to 801 g. As with the other flaps described in this chapter, the third costal cartilage is removed to expose the recipient internal mammary vessels. The donor area is closed with minimal undermining as needed (Fig. 14). The patient is then repositioned supine for microvascular anastomosis and flap insetting.

For bilateral simultaneous GAP flap reconstruction, the patient is supine for mastectomy and recipient vessel preparation. Then, in the prone position, both flaps are harvested and the donor sites are closed. Microvascular anastomosis and flap insetting are performed in the supine position to complete the procedure.

Gap flap success has been 100% in 70 cases, with no fat necrosis noted. Donor site seroma formation is fairly common but has decreased with the use of compression garments. Donor site morbidity is minimal, with ambulation on the first postoperative day and discharge on the second or third day after surgery.

In approximately 25% of patients presenting for breast reconstruction, the lower abdomen is not a suitable donor site. In these patients, the buttock is an excellent donor area for autogenous reconstruction (Figs. 15-18).

FIG. 15. A: A 33-year-old nulliparous woman underwent a modified radical mastectomy for ductal carcinoma. Note midline abdominal scar and inadequate excess tissue in the lower abdomen. B: The donor site was marked in the swim suit line before superior gluteal artery perforator flap reconstruction. C: S-GAP flap skin island measured 26 x 9 cm with a weight of 494 g.

FIG. 15. Continued. D: S-GAP flap reconstruction at 3-year follow-up. E: Donor site.

FIG. 16. A: A 34-year-old Jehovah's Witness has carcinoma of the right breast. The patient is nulliparous with inadequate volume of tissue in lower abdomen. B: Donor site is marked with a 28 x 9 cm skin island. C: S-GAP flap with two perforators merging into the superior gluteal artery and vein. D: Right S-GAP flap reconstruction at 2-year follow-up.

FIG. 17. A: A 55-year-old woman with severe capsular contractures and ruptured implants 27 years after augmentation mammoplasy. B: Donor sites marked for bilateral S-GAP flaps. C: Calcified capsule with ruptured gel implant. D: Bilateral S-GAP flap augmentation mammoplasty at 1 -year follow-up. E: Oblique view. F: Donor site with improved contour and buttock lift.

FIG. 18. A: A 25-year-old woman with Poland's syndrome has congenital absence of the left breast and partial absence of the pectoralis muscle. The patient is nulliparous and has no excess tissue in the lower abdomen. Previous attempts at implant reconstruction were unsuccessful. A plaster mold of the normal right breast calculated the volume to be 350 ml. B: S-GAP flap marked on the left buttock with Doppler localization of perforators. Skin island measured 22 x 8 cm. C: Initial flap weight was 467 g, based on one perforator. Final flap weight was 394 g after insetting. D: Four-year postoperative follow-up of S-GAP flap reconstruction of the left breast. E: Oblique view postoperatively. F: Donor site (left buttock) 4 years post-surgery.