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As the diagnosis of breast cancer increases, so does the amount of information available to the patient regarding treatment. Patients have become more informed regarding treatment and reconstructive options in recent years. The plastic surgery community has attempted to provide reconstructive options that give the best result with the least donor-site morbidity. By using these criteria, the deep inferior epigastric artery perforator flap (DIEAP) flap has been developed based on previous experience with the free and pedicled transverse rectus abdominis myocutaneous flap reconstruction. The DIEAP flap provides autologous tissue for breast reconstruction, which is similar in makeup to the patient's own breast, while minimizing donor-site morbidity. Over the past decade, the DIEAP flap has been a reliable and reproducible method for autologous breast reconstruction.
The use of perforator flaps for autologous breast reconstruction has developed in an effort to perform a safe, reliable, reproducible reconstruction with low donor-site morbidity. The skin and subcutaneous fatty tissue of the lower abdomen provide tissue that has a soft texture and also provides adequate tissue for symmetric breast reconstruction. The use of abdominal flaps as a free flap by Holmstrom and Robbins,1,2 or as a pedicled flap by Hartrampf et al,3 provided the information to describe the perforators of the inferior epigastric vessels. Using this information, Koshima and Soeda reported the first clinical use of the lower abdominal skin and fatty tissue for breast reconstruction without sacrificing rectus muscle.4 The use of the deep inferior epigastric artery perforator flap (DIEAP) for breast reconstruction was then popularized by Allen and Treece.5 Since that time, the use of the DIEAP has become the gold standard for breast reconstruction in many centers.6,7,8
The skin and fat of the lower abdominal wall is lax with zones of adherence at the linea alba and at the umbilicus. The soft consistency of the fat is ideal for breast reconstruction, as it gives a soft, natural reconstruction. The blood supply to the lower abdominal wall, which is of interest in DIEAP reconstruction, arises from the external iliac artery. The deep inferior epigastric artery (DIEA) arises from the terminal aspect of the external iliac artery deep to the inguinal ligament. The DIEA ascends from the lateral aspect of the rectus abdominis muscle toward the umbilicus. It ascends between the transversalis fascia and the peritoneum, where it penetrates the posterior aspect of the rectus abdominis muscle. Milloy et al found that the artery enters the middle third of the muscle most frequently (78%), with the lower (17%) and upper third (5%) less frequently.9 Once penetrating the muscle, it takes on a variety of branching patterns with an average of five (plus or minus two) perforators supplying the skin. Most of the perforating vessels are found within 2 cm cranial and 6 cm caudal and between 1 to 6 cm around the lateral aspect of the umbilicus.10,11 The lateral perforators may be larger and easier to dissect, but the midline perforators supply better blood flow to zone III and to zone IV, which is farthest from the vascular pedicle (Fig. 1).12,13,14 As such, the medial perforators supply better blood flow, but the dissection involves a longer intramuscular course with more extensive longitudinal muscle splitting. Perforators that pass through the rectus muscle at the level of the tendinous insertions are generally large with few side branches. At this location, the distance to the skin is also shorter, which decreases the complexity of the dissection.
Surgical planning of the DIEAP flap involves evaluation of the skin of the lower abdomen. The proposed skin island should be centered over the identified perforators and not necessarily over the middle of the abdomen. Although this is true, careful planning of the final surgical incisions should consider the final skin closure (Fig. 2). Better understanding of perforator perfusion and flap anatomical zone are reported recently.12,13,14 Consideration is also given to the fact that when using the DIEAP flap, zone IV can be utilized if the patient requires added bulk for reconstruction. A duplex Doppler scan is advantageous prior to surgery.15 Using a 1-cm grid system and the umbilicus as 0 for the x- and y-axes, the results of the Doppler examination are marked on the trunk.15 This gives detailed information regarding the location, size, and flow of the perforating vessels, as well as information regarding the thickness of the adipose tissue. Information regarding scarring, unusual vessel course, and obstruction of the pedicle can also be obtained. More recently, multidimensional computed tomography (CT) scan of the lower abdominal wall has been introduced to evaluate the blood supply of the abdominal wall and mapping of the perforator.16 Three-dimensional reconstruction of CT findings gives a road map to the most favorable perforators (Fig. 3), decreasing operative time and aiding with intraoperative decisions. If a duplex examination or multidimensional CT scan is unavailable at the surgeon's institution, a handheld Doppler probe can be used preoperatively to localize the perforators.
During the preoperative markings, the patient should be in both standing and supine positions. The design of the skin island is similar to that of a transverse rectus abdominis myocutaneous (TRAM) flap. It is fusiform in shape and designed over the selected perforator. The usual borders are from the anterior superior iliac spines laterally, the umbilicus, and the suprapubic crease. The average measurement is dependent on the individual patient, but typically measures 30 to 45 cm in width and 13 cm (11 to 16 cm) in height. The estimated tension of the closure will be the limiting factor for the flap dimensions. The fat in the flanks may also be included in the lateral aspects of the flap if the extra tissue is required.
In the operative theater, the patient is placed in the supine position with the arms placed beside the trunk. This allows the surgeon access to the thorax and abdomen during the case. A two-team approach is preferred to perform simultaneous dissection of the abdominal flap and the recipient vessels. Of course this depends on factors such as the timing of mastectomy and availability of staff at the surgeon's institution.
The lower incision is made carefully, to preserve the superficial inferior epigastric vein with the longest length possible. This is useful for flaps, which require additional venous drainage,17,18 because a second venous anastomosis may be performed on the ipsilateral or contralateral aspect of the flap using the superficial inferior epigastric vein. This improves overall venous drainage and may also augment venous drainage of zone III in a large reconstruction if necessary.
The incisions are then carried down to the abdominal fascia. Scarpa's fascia is carefully maintained, and beveling is performed at the lateral aspects and at the level below Scarpa's fascia only. Using electrocautery, the flap may quickly be raised at the suprafascial level to the lateral border of the anterior rectus fascia. When available, the surgeon may use the duplex results as a guide to proceed with the dissection. When a perforator is encountered, the caliber and location of the vessels are assessed. If the caliber and location are deemed unacceptable, that perforator is sacrificed. When only handheld unidirectional Doppler was used, it may be necessary to maintain as many perforators as possible. Once these are assessed, the largest perforator can then be chosen. A large dominant perforator when identified for use can successfully supply the entire flap (Fig. 4). It is also possible to use multiple perforators in the same row if they are small.
Once the desired perforator is identified, the anterior rectus fascia is then incised with a pair of scissors. There is usually a small gap in the anterior rectus fascia through which the perforating vessels pass. This is incised in the direction of the fibers of the rectus muscle (Fig. 5). If the surgeon has limited experience performing this maneuver, a small cuff of fascia may be left around the vessels to avoid injury to the vascular bundle. It is important to note that the course of the vessel may be directly adherent to the deep surface of the rectus fascia, and care must be taken during the initial opening of the fascia. Division of the fascia should be continued superiorly for a distance of 1 to 3 cm to aid with intramuscular dissection and for later division of superior branches.
During intramuscular dissection, the muscle fibers should be split in a longitudinal direction in the direction of the rectus muscle fibers. More adherent fibers are found in regions of side branches and motor nerves (Fig. 6). The side branches should be carefully ligated with surgical clips 1 to 2 cm from their origin. Using a combination of sharp dissection with fine surgical scissors and bipolar diathermy, the perforator is dissected and the side branches isolated and divided. Dissection of the perforator continues toward the origin at the deep inferior epigastric vessel (Fig. 7). If a large side branch is identified, it should be maintained. This is especially important if the branch is arterial, because this would allow for a second arterial anastomosis.19 When identifying multiple small perforators in the same row, one must consider the motor innervation of the rectus abdominis muscle. It may be necessary to divide the intervening nerve branch, and if this occurs, they should be reapproximated after the flap is raised. If more than one perforator is chosen in the same plane, the rectus abdominis fibers must be widely separated. If the perforators are in different planes, the intervening fibers must be divided. It should be noted that transection of large portions of the rectus abdominis muscle should be avoided.
The fascial incision should extend inferiorly and obliquely toward the lateral border of the rectus muscle. In an effort to avoid later hernias or abdominal bulging, a separate incision at the lateral inferior border of the rectus muscle near the inguinal ligament is recommended (Fig. 8). This second incision avoids a continuous area of weakness, thereby avoiding the possibility of bulging, especially in obese patients. Obesity is considered the major risk factor of bulging and hernia after harvesting free abdominal flaps.20 The lateral border of the rectus abdominis muscle is then retracted using noncrushing clamps. The muscle is raised and retracted medially so that the proximal portion of the pedicle is freed, and the origin of the deep inferior epigastric vessels can be dissected from the underlying fatty tissue (Fig. 9). Once all of the side branches are divided and the pedicle is free near its origin to the entrance into the subcutaneous abdominal fatty tissue, perfusion may be checked and the contralateral abdominal flap dissected. It is not necessary to dissect the vessels completely to their origin at the iliac artery and vein. Enough pedicle length can generally be obtained without this extensive dissection to the iliac vessels. The deep inferior epigastric vessels are clipped and the flap is ready for transfer (Fig. 10).
Typically the anastomosis is technically easier with the contralateral lower abdominal flap, because of the position of the artery and vein, but an ipsilateral flap can be also easily anastomosed because of the large arc of rotation of the perforator due to the long pedicle in DIEAP flap. The internal mammary vessels are our vessels of choice,21 with the thoracodorsal vessels as another good option for inflow. Once the anastomosis is complete, the flap is allowed to perfuse for a short period of time and is inspected for arterial inflow and venous congestion. This is most easily accomplished during the shaping of the flap. The flap is shaped for inset on the chest after the anastomosis is complete. The flap should have signs of arterial bleeding from the edges, and dark venous bleeding should be at a minimum. It is important to maintain the superficial inferior epigastric vein during shaping to be used as a second venous anastomosis in cases of venous congestion. If necessary, all abdominal zones may be used for breast volume, but zone IV is typically discarded in unilateral reconstruction. The flap may be secured in position with surgical staples and the patient placed in a seated position to assess for symmetry. Once satisfied with the shape and size, the flap is inset over drains with the buried portion de-epithelialized. Placement of the drains should carefully avoid contact with the pedicle. In some cases the nipple areola complex may be recreated at the time of inset. This is at the discretion of the operating surgeon and is not recommended if there are any questions of flap viability or during delayed reconstructions.
The fascia of the abdomen is closed in layers using nonabsorbable sutures (Fig. 11). If the patient has a rectus diastasis, rectus plication can be performed in the manner of a cosmetic abdominoplasty.22 The soft tissue of the abdomen is closed over drains with the patient in flexed position (Fig. 12). A long suture is left on the umbilicus for easier identification when the incision is made for inset. This allows the umbilicus to be easily pulled into place for less traumatic inset.
Patients stay in the intensive care unit for the first postoperative night, then are transferred to the ward. They receive standard intravenous (IV) fluids. We use Nootropil® (UCB Pharma, Brussels, Belgium) (Piracetam) 12 g/24 hours IV for 5 days and a 20% solution orally, 25 mL four times a day, for postoperative days 6 through 10. This drug has been shown to increase the viability of the distal portion of skin flaps due to an increase in the capillary blood flow.23
Monitoring of the flap is accomplished using a combination of techniques. Clinical evaluation of the color and capillary refill, temperature, handheld Doppler, and implantable Doppler devices may all be used for monitoring. The patient's core temperature should be maintained with a warm room, warming blanket, and warmed fluids as needed. The use of vasoconstrictive agents should be avoided.
Similar to large published studies,24 our experience with breast reconstruction DIEAP flaps exceeds 1200 cases. The microanastomosis revision rate is estimated at 5% with total failure rate of 1%; partial flap failure and/or fat necrosis is 8% on average. Regarding concern with the donor-site morbidity, bulging still occurs in less than 1% of our patients. Patients who have factors that increase intra-abdominal pressure or weaken the abdominal wall, such as high body mass index, multiple-scar abdomen, or active smoking history, have higher potential risk of developing abdominal bulging or asymmetry.
For surgeons beginning to use the DIEAP flap for reconstruction, it is recommended to use this technique first for a unilateral reconstruction until proficiency is achieved. The DIEAP flap is contraindicated in those patients who have already had cosmetic abdominoplasty. Smoking is not an absolute contraindication for free flaps,25 but patients who are candidates for elective surgery are requested to cease smoking at least 1 month before surgery. Relative contraindications for DIEAP reconstruction include previous abdominal liposuction, multiple abdominal scars, lack of adequate tissue volume, and poor overall medical conditions.25,26,27 However, a DIEAP free flap could still be harvested if intact and sizable perforators are shown by preoperative image techniques such as duplex or CT scan.
The use of the DIEAP flap for breast reconstruction allows for a breast with a natural appearance and texture (Figs. 13–16). This is an excellent option for those patients who request autologous reconstruction, those who have adequate tissue for reconstruction, and those medically acceptable for surgery.5,6,7,8,24 The DIEAP flap, like other perforator flaps, relies on different techniques in flap harvesting. For beginners or trainees, the learning curve is obviously the major challenge as in any new technique. As such, perforator flaps should be included in every training program. In addition, attending perforator flap courses together with visiting centers where large numbers of perforator flaps are performed will shorten the learning period and significantly decrease the complication rate that may occur during early experience. Using image technology such as duplex or spiral CT scan in planning of perforator flaps is essential to make this technique more reliable among inexperienced hands. Precise preoperative perforator mapping will significantly shorten the operative time and decrease complications related to poor perforator choice. A unilateral DIEAP flap breast reconstruction takes 3 hours in our hands, thanks to precise preoperative surgical planning using the new image technology in perforator mapping. Moreover, partial flap failure and/or fat necrosis in DIEAP flaps can be reduced by choosing the dominant perforator. However, flap blood supply may be insufficient in the case of multiple tiny perforators. Therefore, conversion of a DIEAP flap to a TRAM flap seems safer and easier than dissecting three or more perforators, which may cause similar damage to the rectus muscle when compared with a muscle-sparing free TRAM flap.
Perforator flaps have major advantages in decreasing donor-site morbidity.6,28,29 However, long-term complications can still occur. Careful closure of the deep fascia is among standard requirements, but in weak abdominal wall musculature, additional procedures may be necessary. Additional fascial plication or even use of a mesh is recommended in multiple scar abdomen or obese patients.
The DIEAP free flap is our first choice for breast reconstruction. It is a safe and reliable technique with an acceptable complication rate. Preoperative mapping of the perforators using radiological imaging techniques has revolutionized this technique in terms of decreasing operative time and postoperative complication rates. Some patients with high body mass indexes or smokers may present a higher risk for abdominal complications. Therefore, additional procedures such as fascial plication with or without use of mesh is recommended in these patients.