I-GAP Flap (Inferior Gluteal Artery Perforator Flap) or "In-the-Crease" GAP Flap
The "In-the-Crease" GAP flap is one of Dr. Marga’s favorite flaps as this was the first microsurgical perforator flap she completed in 2004!
Stage 1 of this reconstructive technique includes the transfer of skin, fat and the associated blood vessels that keep it alive transplanted from the buttock to the chest wall. This flap differs for the S-GAP flap as the donor site places the scar "in the crease" beneath the buttock. No muscle or motor nerves are sacrificed in the execution of this form of breast reconstruction. Blood vessels of the flap are connected to either blood vessels in the chest wall or under the arm in the axilla using an operating room microscope. Unilateral and Bilateral I-GAP flap breast reconstruction can be performed in a 8-10 hour general anesthetic in the setting of a 4-day hospital stay with a focus on flap monitoring. This procedure is longer because of the need to turn the pateint on the operating room table and a higher level of flap dissection difficulty. It is a minimally painful operation, less than a TRAM, DIEP or SIEA flap. Blood thinners are administered to prevent deep venous thromboses or pulmonary emboli. Costochondral cartilage or rib resection is uncommon due to the long length of the blood vessels of the flap.
Stage 2 of this technique involves the aesthetic shaping of the breast reconstruction flap and the completion of any counterbalancing procedures of the remaining breast (breast reduction, breast lift or breast augmentation). Excess skin from the flap previously placed for perioperative monitoring will be removed. Revisions to the donor site include liposuction and scar revisions. Nipple reconstruction is completed at this stage. On occasion in the irradiated patient, nipple reconstruction is deferred to a later date allowing for the revised reconstruction to settle, therefore optimizing nipple placement. Stage 2 procedures can be completed in a 2-hour MAC anesthesia in an outpatient setting. Areolar reconstruction will be completed as a Stage 3 procedure in 2 months in the office.
Common complications of I-GAP flaps are seromas or collections of fluid under the skin that may require needle aspiration.
I-GAP total flap failure can be seen in less than 2% of cases.
Flap failure can result from 3 etiologies:
1. Inadequate flap blood vessel anatomy (i.e. congenital or secondary to injury in the setting of prior liposuction);
2. Inadequate recipient blood vessels in the chest or axilla (likely secondary to prior surgery, irradiation, or prolonged exposure to silicone gel);
3. Injury to the essential blood vessels of the flap at the time of surgery;
I-GAP total flap failure is diagnosed prior to your release from the hospital. Most patients with a failed I-GAP flap undergo a secondary microsurgical flap procedure during the same hospitalization or at a later date, typically at 3 months, in the form of a Bi-Pedicle DIEP flap (see above) or an I-GAP from the other buttock.
I-GAP partial flap loss is commonly referred to as fat necrosis. Fat necrosis can present as a firm area of the breast reconstruction flap where the blood supply was not adequate enough to keep the tissue soft and viable. It likely represents an anatomic variant of the individual (not unlike a "hole" in your Christmas tree…), OR possibly the poor choice of the I-GAP perforator to support the flap reconstruction. The desire to avoid fat necrosis fuels Dr. Marga’s desire for a pre-operative CT or MR angiogram so your procedure can be based on the most robust blood vessel of your gluteal region.
Dr. Marga is a microsurgery-fellowship-trained Plastic Surgeon with a focus on I-GAP flap breast reconstruction at the Center for Restorative Breast Surgery. She would be pleased to discuss with your the differences in the selection of I-GAP vs. S-GAP flap breast reconstruction in the setting of your office or phone consultation.