Perforator Flap Breast Reconstruction Treatment & Management

Deep inferior epigastric perforator flap

In patients with adequate abdominal fatty tissue volume, the deep inferior epigastric perforator (DIEP) flap is typically chosen. This procedure was originally described by Koshima in 1989^[2] and allows harvest of excess fat in the lower abdomen without rectus muscle sacrifice.^{[7, 8]} This carries the advantage over the transverse rectum abdominus myocutaneous (TRAM) flap of muscle preservation in the anterior abdomen.^{[9, 10]} The advantages of donor scar placement in an aesthetically acceptable location and an improved resultant abdominal contour contribute to selection of the DIEP flap as a first-line modality. The avoidance of intraoperative repositioning compared to the gluteal artery perforator (GAP) flap also provides for shorter relative surgical times.

Superficial inferior epigastric artery flap

The superficial inferior epigastric artery (SIEA) flap allows for harvest of the lower abdominal fatty tissue based on the superficial inferior epigastric system. Occasionally, the flow from the superficial system may be more robust than that of the deep inferior epigastric system. If the perforators of the deep inferior epigastrics are judged to be of insufficient size or location because of either previous surgery or atypical anatomy, the superficial epigastric system may serve as a logical alternate flow source.

The SIEA flap is not preferred over the DIEP flap because the superficial artery is usually of much smaller caliber than the deep inferior epigastric artery, and the superficial artery is usually tortuous in its proximal origin point from the common femoral. The advantage of no muscular dissection may make the SIEA flap a preferred choice. However, in the authors' experience, the vascular issues associated with the pigtailed small artery and the higher incidence of seroma due to dissection through the groin lymphatics make the SIEA flap a secondary or backup choice in most cases.

Superior and inferior gluteal artery perforator flaps

For patients who have inadequate abdominal soft tissue volume or who have undergone prior abdominal surgeries that have compromised the abdominal perforating vessels, the GAP flap is selected. The GAP flap evolved as a refinement of the gluteal myocutaneous flap, which was first described in 1975 by Fujino et al for reconstruction of the aplastic breast.^[11] Koshima's work in 1993 led to the original descriptions of the GAP flap for management of sacral pressure sores.^[3]

Numerous applications have evolved for this flap, including breast reconstruction.^{[1, 2]} The GAP flap allows for harvest of substantial amounts of fatty tissue, even in patients who are very thin. The avoidance of gluteal muscle sacrifice minimizes long-term morbidity and shortens recovery. The donor site is in an aesthetically acceptable location with minimal resultant contour changes in the buttock.

The inferior gluteal artery perforator (IGAP) flap is essentially the same operation as the superior gluteal artery perforator (SGAP) flap, but with lower positioning of the flap on the buttock. In this lower position, the feeding vasculature emanates from the inferior gluteal artery, which passes below the piriformis muscle (in contradistinction to the superior gluteal artery, which passes over it). The sciatic nerve also passes inferior to the piriformis muscle; the added need for dissection around this nerve bundle also distinguishes the IGAP flap from the SGAP flap. The IGAP flap is not commonly chosen for routine perforator flap breast reconstruction for these reasons, along with the fact that the donor site may suffer contour effects that mimic the male buttock shape. Patients with thin upper buttocks and adequate lower buttocks may benefit from movement of the donor site to a lower position with adequate discussion of anticipated effects.

Stacked/layered DIEP flap

For women who are too thin for breast volume restoration with a routine single DIEP flap reconstruction, 2 flaps may be combined into a single breast reconstruction with the stacked DIEP flap technique. This allows 2 independent flaps to be linked to one another and layered into the breast reconstruction site. This provides another option for a thin patient who needs a single breast reconstructed (presented at the Annual Meeting of the American Society of Reconstructive Microsurgery in January 2008).^{[12, 13]}

“Body lift" perforator flap: Stacked abdomen/hip flap

For women with inadequate volume in the abdominal and gluteal donor regions, the stacked abdomen/hip flap may be appropriate. This procedure allows for the DIEP flap to be layered with the GAP flap. This stacking method incorporates 4 flaps to provide sufficient volume in bilateral breast reconstruction.

Lumbar perforator flap

In patients with adequate soft tissue in the lumbar region, this area may be used as a donor site for free fat transfer. The perfusion of this flap depends on the vasculature from the lumbar perforators that penetrate the fascia superior to the gluteus medius and posterior superior iliac spine.

Lateral thigh flap

The lateral thigh flap is another option. It is described here for completeness but is very rarely performed because the donor site morbidity is less acceptable than with other options. The amount of tissue that can be harvested is minimal, and the scar rests in an aesthetically challenging location. The flap is based on musculocutaneous perforating vessels that pass through the tensor fascia lata. The vessels originate from the lateral femoral circumflex system.

Thoracodorsal artery perforator flap

The thoracodorsal artery perforator (TDAP) flap is another rarely chosen source for autogenous tissue breast reconstruction. An evolution of the latissimus myocutaneous flap, the TDAP flap allows for collection of skin and soft tissue from the upper back without sacrifice of muscle tissue. The flap is based on proximal perforating vessels that originate from the thoracodorsal artery and vein. These vessels pass through the latissimus dorsi muscle and into the overlying skin and fat.

DIEP flap

Harvest of the free flap is initiated with an incision along the lower arc of the premarked elliptical skin incision. This allows for identification and inspection of the superficial inferior epigastric artery (SIEA) and associated veins prior to searching for the perforating branches of the deep inferior epigastric vessels. This maneuver provides 2 advantages. First, the size of the vessels in the superficial system may give a sense of whether the superficial system is more dominant than the deep system. Second, if the perforating branches are injured during dissection or affected by fascial scarring from prior surgery, the superficial system may be used to supply the flap as a backup source of blood supply. The authors do not routinely choose the SIEA flap over the DIEP flap because the artery is often tortuous as it loops back toward the common femoral artery and it is typically 1.5-2 mm in diameter, even when very well-developed.

Once the superficial system is identified, harvest of the flap proceeds with completion of the upper arc of the skin incision. The whole flap is then elevated in a plane superficial to the fascia of the muscular abdominal wall. The lateral row perforators are encountered first and are selected as the supplying vasculature, if adequately developed, which is the case in approximately 90% of patients.

The lateral row vessels more often maintain a rectilinear course and, thereby, facilitate dissection with shorter intramuscular courses. If the medial row perforators are better developed, they may be chosen; however, they have a less central position under the bulk of the flap.

Once the desired perforators are chosen, the lateral row vessels are delicately dissected from their penetration point in the rectus fascia. A connecting incision is created in the rectus fascia between these perforating vessels, and the dissection proceeds down to the common deep inferior epigastric trunk. Surrounding fibers of the rectus abdominus are gently teased away from these vessels, and crossing motor nerve fibers are identified and preserved. Once a pedicle of adequate length and caliber is achieved, the flap is harvested via ligation and transsection of the pedicle at its proximal origin point. The fascial incision is then repaired with a nonabsorbable suture and the abdominal wound is closed.

The authors rely solely on the internal mammary vessels for the recipient vasculature; these are prepared by releasing the pectoralis origins over the desired costal cartilage in the reconstructive bed. The perichondrium is stripped, and a small segment of costal cartilage is resected alongside the lateral sternal border. Once completed, removal of the deeper perichondrium exposes the internal mammary arteries and associated veins. The veins are typically smaller on the left than the right but serve adequately even when small. These vessels are reliable and easy to expose, even in radiated tissue beds. Alternatively, the thoracodorsal vessels may be selected as the recipient vessels, when necessary.

Once the microvascular anastomosis is completed between the flap's pedicle and the recipient vasculature, the flap is contoured and inset to provide the new breast mound. Patients typically spend 3-4 days in the hospital prior to discharge. Nipple reconstruction follows at 6-8 weeks, and final pigment application takes place to complete the nipple and areolar reconstruction in the weeks following.

Stacked DIEP flap

Flap dissection proceeds as with a standard DIEP flap reconstruction. As deep inferior epigastric vessels are identified, the branch points are carefully inspected. All large branches, including the distal extent of the deep inferior epigastric, are dissected for length and ligated to serve as anastomosis points for the second flap. Once the pedicle dissection is completed, attention is directed to the opposite hemi abdomen. The second flap is dissected in a manner similar to that of the first flap. Once the pedicle is dissected free, the flaps are harvested.

The ipsilateral abdominal flap is then deepithelialized and inset into the breast pocket dermal side down. The vascular pedicle is oriented appropriately to provide alignment with the planned anastomotic branch point in the opposing flap. The second flap is placed atop this flap with its pedicle draped into the site for anastomosis to the recipient internal mammary vessels.

Anastomosis is then completed between the venae comitantes of the deep inferior epigastric system and the internal mammary veins. Arterial anastomosis is then carried out with 9-0 nylon. Cook implantable Doppler probes are then applied to the arterial and venous anastomosis sites. Anastomosis of the selected branch point of this primary pedicle to the pedicle of the deeper flap is then completed similarly. The overlying flap is carefully positioned and secured in place, and inset is completed. Volume of the final reconstructed breast is tailored with trimming of the deeper flap before it is inset and trimming of the superficial flap once anastomosis is complete.

SIEA flap

In the case of the SIEA flap, the blood vessels are encountered along the lower arc of the abdominal incision pattern and rest in the subcutaneous fat just below the skin surface. The arterial pedicle may be followed down to the origin point at the common femoral artery via careful opening of the femoral sheath. The artery is typically smaller than the deep inferior epigastric system and turns on itself as it enters the femoral sheath, creating a tortuosity in its final few millimeters.

The venae comitantes with this artery are occasionally well-developed enough to serve as the outflow for the flap, but, more commonly, the superficial inferior epigastric vein provides a more adequate source of venous egress. This vein may emerge several millimeters from the arterial pedicle, and care must be taken not to injure it with the initial skin incision. Dissection of the vascular pedicle requires working through the groin lymphatics and may, therefore, increase the drain time required and the chances of postoperative seromas.

SGAP flap

Harvest of the SGAP flap is initiated with placement of the patient in the prone position. The perimeter of the flap is defined with electrocautery, and incision through the superficial fascia of the gluteus maximus follows. The subfascial plane is then entered and serves as the plane for perforator identification. Once the dominant perforator or perforators are identified, selection is made based on size and location of the feeding vessels. The perforators are then followed down through the substance of the muscle by spreading and preserving the fibers.

The connective tissue of the perimysia around the vessels serves as a layer that may be handled easily and speeds the dissection of the perforator. The dissection is then carried through the deep gluteal fascia to reach the larger caliber vessels in the subgluteal fat pad as they emerge from the sacral foramina. Extreme care must be taken in this portion of the dissection, as entry into the large venous confluence or a poorly controlled arterial branch point in the tight confines of this portion of the harvest can make for unnecessary blood loss and possible injury to the flap pedicle.

Once adequate vascular caliber is attained, the flaps are harvested and passed off the field. The donor sites are closed, and the patient is returned to the supine position. The flaps are then brought into the field, where they are contoured and de-epithelialized prior to completion of microvascular anastomosis. The internal mammary vessels are again chosen as recipients. They are particularly suited to the GAP flap because they allow for medial positioning of the flap and avoidance of vein grafts, since the flap's pedicle is usually short (4-6 cm). Once anastomosis is complete, the flaps are shaped and inset. Nipple reconstruction and pigmentation of the nipple areolar complex follow.

TDAP flap

To dissect the TDAP flap, perforating vessels are identified in the subfascial plane of the latissimus, and the muscle is split in the direction of its fibers. These vessels are then followed to the submuscular branches of the thoracodorsal system as the thoracodorsal nerve is identified and preserved. This pedicle is then followed to its origin from the subscapular artery and vein. The flap may then be either passed through the opening in the muscle to rotate anteriorly or harvested for free tissue transfer. The resultant scar is difficult to conceal, and the amount of available tissue is adequate only in patients who are obese. For these reasons, this flap is not chosen as a primary source of tissue for autogenous breast reconstruction. It may, however, serve as a viable option for wound closure or in patients in whom a flap procedure has failed and other donor sites are precluded.

Intercostal artery perforator flap

The intercostal artery perforator (ICAP) flap is designed as a fasciocutaneous pedicled flap and is based anteriorly. The base of the flap is marked out at a width of 6-7 cm and is located at the anterior axillary fold. A triangular-shaped extension from this base is then marked out, extending posteriorly at the level of the inframammary fold. The axis of the flap is designed over the corresponding rib, and its length may be tailored up to approximately 12-15 cm. The flap is then dissected in a deep plane, including the fascia of the serratus anterior. Some perforating intercostals are transected as the dissection marches anteriorly, but the dissection should stop short of transecting the feeding perforators emanating between the slips of the serratus anterior. The flap may then be rotated into the corresponding defect to complete wound closure or augment lateral breast insufficiencies.^[14]

Patients who undergo perforator flap breast reconstruction are typically hospitalized for 3-4 days after the surgery. Follow-up care after discharge from the hospital includes management of any remaining drain tubes and avoidance of strenuous activities for 6 weeks. Most patients resume basic normal activities within a week after returning home and should return to the clinic for follow-up to assess for proper healing and progress.

Perforator flap breast reconstruction is a technically demanding art and requires extensive training in microsurgical free tissue transfer. Success rates with respect to complete flap loss improve as experience increases. Surgeons who routinely perform these procedures may have success rates of more than 99%. However, free flaps for free tissue transfers carry general success rates of 93-95%.

Partial flap loss is very rare, as blood flow within the harvested flaps is typically vigorous. Fat necrosis has not been shown to be more common than in techniques that include muscle tissue with the harvested flaps. Seromas may occur at the donor site and are most often treated with simple aspiration. Hematomas are no more common in perforator flap reconstruction than in other tissue transfer techniques. Infection rates are comparable to any other elective breast surgery. Abdominal bulge and hernia are less common than with the transverse rectus abdominus myocutaneous (TRAM) flap technique.^[4]Deep vein thrombosis (DVT) and pulmonary embolus prophylaxis are important per standard guidelines.^[15]

Perforator flap breast reconstruction is a powerful tool that may provide a breast reconstruction composed of living tissue. Once reconstruction is complete, the breast should be essentially maintenance-free and should be a lifelong solution for the affected breast. The aesthetics of the reconstructed breast can be excellent in most cases, and the added benefit of minimized disruption of muscle structure can make this type of procedure an appealing option for women seeking breast reconstruction.

Perforator flap breast reconstruction represents a significant surgical advancement in and of itself. Additional applications beyond mastectomy reconstruction include correction of lumpectomy defects and congenital breast deformities such as Poland syndrome. Perforator flap techniques may also be considered for patients seeking autogenous augmentation or replacement of troublesome implants.