S-GAP & I-GAP Perforator Flaps
WHAT IS A S-GAP FLAP?
S-GAP (Superior Gluteal Artery Perforator) Flap is used for women who have very thin abdominal tissues that are inadequate to create a breast mound.
This flap is similar to the Superior Gluteal Myocutaneous Flap but without a muscle component. It is based on the superior gluteal artery and consists of the skin and fat from the upper hip and buttocks area, but spares the muscle, and therefore has a longer vascular pedicle. The incision line is designed to be hidden by your undergarments.
WHAT IS AN I-GAP FLAP?
I-GAP (Inferior Gluteal Artery Perforator) Flap that spares the gluteal muscle, but includes an ellipse of skin and subcutaneous tissues from the lower hip and buttock area served by the inferior gluteal artery perforator.
There are two Gluteal Artery Perforator flaps. The S-GAP utilizing the superior gluteal artery perforator as its blood supply, and the I-GAP or inferior gluteal artery perforator as its blood supply.
These flaps can be used for bilateral breast reconstruction and are often dissected simultaneously by two surgeons. These flaps are less frequently used than DIEP flaps because they are more difficult to dissect, and because the patient must be turned over twice to perform these flaps.
The patient begins on her back for the mastectomy surgery. After mastectomy has been completed, the internal mammary arteries and veins are prepared for microvascular anastomosis and the wounds are dressed.
Then the patient is turned onto her stomach, the buttocks are prepped and the pre-operatively determined position of the perforators and skin paddle once confirmed with an ultrasound Doppler.
Then using microscope loupes, the dissection begins with an incision of the skin paddle down through the skin and subcutaneous (fat) tissue to the muscle. This paddle is elevated from lateral to medial up to the area of the large perforator (or two).
Then the gluteal artery perforator is followed through the gluteus muscle by splitting the muscle fibers, dividing and cauterizing small muscle branches until main gluteal artery (superior or inferior depending on the flap chosen) is reached.
The gluteal artery is then dissected out and prepped for division. The gluteal artery and vein pedicle is then tied and divided. The S-GAP and I-GAP flap(s) are then put on the side table while the gluteal donor site wounds are closed and dressed.
The patient is then placed on her back; the chest is again prepped and draped sterily. The S-GAP (or I-GAP) flap (s) is brought to the mastectomy site and microvascular anastamosis performed to immediately re-establish circulation. The flaps are then tailored and inset to create symmetrical breast mounds.