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

The Deep Inferior Epigastric Perforator Flap

This procedure uses skin and fat from the lower abdomen. The flap is based on one, two, or three perforators of the deep inferior epigastric vessels. This technique has all of the advantages of the free transverse rectus abdominus myocutaneous (TRAM) flap without the donor site complications of abdominal bulge, hernia, or muscle weakness. The deep inferior epigastric perforator (DIEP) flap may be substituted for the free TRAM flap in all instances and provides the added advantage of preservation of the rectus muscle and anterior rectus sheath.

Preoperative markings are applied with the patient in the sitting and supine positions (Fig. 1). After placement of standard abdominoplasty markings, the Doppler probe is used to identify the main perforators of the medial and lateral branches of the deep inferior epigastric artery. On the chest, the inframammary crease is outlined. In immediate reconstruction, suggested markings are made for skin-sparing mastectomy to include the nipple-areola complex and biopsy site. A slight medial extension may be helpful to improve access to the internal mammary artery and vein for anastomosis to donor vessels. As a distant second choice, the thoracodorsal vessels may be used as recipients. In secondary reconstruction, the mastectomy scar is excised and the breast skin flaps are elevated to recreate the mastectomy defect.

FIG. 1. Typical preoperative markings on the lower abdomen of a patient undergoing breast reconstruction using the DIEP free flap.

The operating room table is rotated 180 degrees, allowing the surgeons to sit comfortably during the microvascular anastomoses of the deep inferior epigastric vessels and the internal mammary vessels. The patient is positioned supine with the arms tucked by her sides. A two-team surgical approach is used, with simultaneous preparation of the recipient area and flap harvest.

FIG. 2. Perforating vessels of the lateral branch of the inferior epigastric artery are visible coursing through the rectus sheath.

With flap dissection, the skin island is carefully elevated from the muscle fascia until the lateral perforators are encountered (Fig. 2). If a large perforator is located, the flap can be based on this alone or with one or two other lateral perforators dissected as a measure of safety. Otherwise, the medial row of perforators is exposed by elevating the skin flap from the opposite site. Usually, about seven perforators are present over each rectus muscle. Often a sensory branch of an intercostal nerve runs with the perforators and may be used to innervate the flap. Once the decision is made whether to use the lateral or the medial row of perforators, the anterior rectus sheath is opened around the desired perforator. Loupe magnification with microsurgical technique is used to dissect the perforating artery and vein(s) through the rectus muscle. Side branches of the vessels are either divided using bipolar forceps or ligated with silk ligatures. The muscle is split in the direction of its fibers to expose the lateral or medial branch of the deep inferior epigastric vessels. Superior to the entry point of the musculocutaneous perforator, the pedicle is doubly ligated and divided. The anterior rectus sheath and muscle are split inferiorly to obtain the desired pedicle length. If necessary, the dissection may be continued past the point where the medial and lateral branches converge into the main deep inferior epigastric artery and vena comitantes in order to assure adequately sized vessels to match the diameter of the recipient vessels. Branches of the intercostal nerves that pass anterior to the deep inferior epigastric vessels should be left intact to avoid denervating the muscle medially. Often, a second or third perforator in line with the first is maintained with the flap. In our experience, approximately 25% of flaps are based on one perforator, 50% on two, and 25% on three. Pure sensory nerves running with the perforators can be dissected for a length of several centimeters for innervation of the new breast. After branches of the pedicle are divided, the skin and fat flap are now an island based on the deep inferior epigastric artery and vein(s).

FIG. 3. Isolation of the internal mammary artery provides an excellent recipient site.

In Fig. 3, the internal mammary vessels are used as recipient vessels. With immediate reconstruction, the mastectomy specimen is weighed and the size and location of skin resection is noted. In secondary reconstruction, the mastectomy scar is resected and the chest skin flaps elevated. The pectoralis major muscle is split in the direction of its fibers medially to expose the third costal cartilage. Once the perichondrium is elevated, the entire rib cartilage is removed. Next, the posterior perichondrium is opened to expose the internal mammary vessels. Using loupe magnification, the vessels are isolated for a distance of 3 to 4 cm. The internal mammary artery is usually an excellent recipient vessel, with a diameter of approximately 3 mm. Of the one or two veins present, the larger vein's diameter varies from 2 to 4 rum. Although these veins are often thin walled, damage during dissection has not been problematic if meticulous technique is used. Care must be taken to avoid opening the pleura. This has occurred in less than I% of our cases and even in those two instances has not resulted in a pneumo-thorax. The flap is harvested by dividing the proximal pedicle and sliding the pedicle under any crossing intercostal nerves present. Once the flap is weighed, it is transferred to the anterior chest wall. At this point, the operating microscope is set up and the vessels are positioned midway between the two surgeons. The flap is rotated 180 degrees and secured inferior to the mastectomy incision, creating ample room for microvascular anastomosis. The larger or only internal mammary vein is ligated distally, divided, and anastomosed end-to-end to the larger or only deep inferior epigastric vein using 9-0 nylon suture. Next, the internal mammary artery is anastomosed to the deep inferior epigastric artery in a similar fashion. After completion of microvascular anastomosis, Doppler probing can identify the precise location on the skin flap where the perforators enter. Marking these positions intraoperatively facilitates postoperative monitoring of the flap. The flap is then tailored to achieve the desired breast size and shape. Using the internal mammary artery as the recipient vessel facilitates medial positioning. Lateral fullness may be avoided by suturing the lateral axillary skin down to the serratus or lateral pectoralis major muscle. After placement of a closed suction drain, the skin island incorporating a perforator is left for postoperative monitoring.

Closure of the donor site is quite simple. The opening in the anterior rectus sheath is closed without tension with a layer of running 0 Prolene. The remainder follows standard abdominoplasty closure of the skin flaps with umbilicoplasty (Fig. 4). A suction drain is brought out through the lateral incision.

FIG. 4. Anastomosis of the internal mammary artery and vein with the inferior epigastric artery and vein and placement of the DIEP flap.

Postoperatively, the patient is monitored in the recovery room for 2 to 3 hours and then transported to the plastic surgery ward. No anticoagulants are given during or after surgery. Often a unit of autogenous blood is given, but banked blood is rarely needed. Flap monitoring by the nursing staff consists of skin color, capillary refill, temperature versus control, and Doppler evaluation. On the morning after surgery, the intravenous and Foley catheters are re-moved and the now ambulatory patient requires only oral analgesics. After discharge on the third postoperative day, the patient resumes normal activity over the next several weeks.

The DIEP flap is particularly suited for simultaneous bi-lateral breast reconstruction. Harvesting two skin flaps from the lower abdomen without any sacrifice of the anterior rectus sheath or rectus abdominus muscle significantly reduces the donor site morbidity often associated with bilateral TRAM flap reconstruction. Avoiding a tight fascial closure or the use of synthetic mesh allows the patient to be ambulatory on the first postoperative day and to require only oral analgesics. Hospitalization lasts 3 to 4 days. In addition, breast symmetry is easier to achieve in bilateral reconstruction.

Complications include the possibility of flap loss, the need to return to the operating room for revision of the venous or arterial anastomosis, and the development of seroma, fat necrosis, or infection. The take-back rate for re-vision of the anastomosis has been 5%, with a flap failure rate of less than 1%. Seroma of the donor site is common (15%) but self-limited. Minor fat necrosis is present in 10% of cases. Significant flap or donor site infection requiring hospitalization has occurred in 3% of patients.
In summary, the DIEP flap is an elegant method of breast reconstruction in a patient with excess skin and fat in the lower abdomen. As Ian Taylor stated, the most coveted donor tissue in the parous female lies transversely across the lower abdomen. This perforator flap technique significantly decreases the potential donor site morbidity associated with the TRAM flap procedure. The DIEP flap has been used in over 300 clinical cases in our institution, with a greater than 99% flap survival rate, establishing this as a reliable procedure. Only one in-stance of abdominal bulge occurred in our series and was due to dehiscence of anterior rectus sheath closure. No muscle weakness has been noted, and current pre- and postoperative evaluation of rectus abdominus muscle strength is underway (Figs. 5-11).

FIG. 5. A: A 43-year-old woman presenting for secondary breast reconstruction of the right breast after having undergone modified radical mastectomy 6 months earlier with postoperative chemotherapy and radiation. Unilateral DIEP flap reconstruction was planned with resection of severely radiation-damaged skin before flap insetting. Note preoperative markings, including Doppler-identified perforator locations. B: Flap shown inset. Conical shape achieved by end-to-end folding of the flap.

FIG. 6. A: A 39-year-old woman presents requesting immediate reconstruction of the right breast after modified radical mastectomy secondary to breast carcinoma. B: One year follow-up of DIEP flap re-construction of right breast.

FIG. 7. A: A 36-year-old woman presents requesting immediate reconstruction after planned simple mastectomy of the right breast for extensive ductal carcinoma in situ. The patient also wished to augment her current breast size. Flap weight was 482 g, as compared with a mastectomy weight of 308 g. A prosthesis was placed contralaterally to achieve symmetry. B: Long-term follow-up of DIEP flap reconstruction of the right breast with prosthetic augmentation of the contralateral side.

FIG. 8. A: A 47-year-old woman requests bilateral immediate reconstruction after planned left modified radical mastectomy and right simple mastectomy for invasive carcinoma of the left breast and ductal carcinoma in situ of the right breast. Because of adequate abdominal donor tissue, bilateral DIEP flap reconstruction was planned. B: Excision of the nipple-areola complex and biopsy site in concert with skin-sparing mastectomy. C: Right DIEP flap shown with marked perforator sites and flap weight. D: Left DIEP flap shown with flap weight.

FIG. 8. Continued. E: Frontal view of bilateral DIEP flap breast reconstruction 5 months post-surgery. F: Oblique view 5 months post-surgery.

FIG. 9. A: Preoperative photograph of a 45-year-old woman who elected bilateral breast reconstruction after having undergone bilateral simple mastectomy for lobular carcinoma in situ of the left breast and fibrocystic disease of the right breast. B: Bilateral DIEP flap markings.

FIG. 9. Continued. C: Insetting of left DIEP flap after microvascular anastomosis. D: Long-term follow-up of bilateral DIEP flap breast reconstruction. E: Oblique view.

FIG. 10. A: A 43-year-old woman, with ductal carcinoma of the right breast and lobular carcinoma in situ of the left breast presenting for bilateral breast reconstruction. B: Long-term follow-up of bilateral DIEP flap breast reconstruction.

FIG. 11. A: A 35-year-old woman with ductal carcinoma of the left breast. B: Three-month postoperative follow-up of DIEP flap breast reconstruction. Right breast mastopexy was performed to achieve symmetry with the reconstructed breast.