Superficial Inferior Epigastric Artery Flap for Breast Reconstruction

Robert J. Allen, M.D., F.A.C.S.,1 and
Andreas S. Heitland, M.D.2

ABSTRACT
The superficial inferior epigastric artery (SIEA) flap is reintroduced as an ideal flap for breast reconstruction. It combines reliable donor and recipient vessels, ease of the technique, and an “acceptable donor scar.” The advantages of the SIEA flap are the minimal donor site morbidity, a low scar, and an esthetically pleasing closure. The authors investigated the anatomy of the SIEA in 100 cadavers and reported the artery present in of 72% of groins. Since 1997, 81 reconstructions and 4 augmentations have been performed in 70 patients at the Louisiana State University Health Sciences Center. The technique and the postoperative results are demonstrated.

KEYWORDS:
Superficial inferior epigastric artery flap, breast reconstruction, donor site morbidity, direct cutaneous artery flap, microsurgery

Since Tansini’s first successful attempt in the late nineteenth century to reconstruct the breast after a radical mastectomy defect, it has always
been a dream to rebuild the ideal breast. After the introduction of the latissimus dorsi muscle with implants2 in 1977 the race for the ideal technique began. The abdominoplasty flap or free rectus abdominis myocutaneous flap was reported by Holmstrom3 in 1979 and showed the right direction in choosing the lower abdomen as the donor site. Paradoxically, the pedicled trans- verse rectus abdominus (TRAM) flap4 followed. Its main disadvantage is the destruction of the integrity of the abdominal wall by harvesting one or both rectus abdominus muscles. The free TRAM5 was not able to prevent a weakening of the anterior wall, with the risk of an abdominal bulge or hernia being the same as the conventional TRAM. This flap also included another oftenneglected disadvantage. Those perforators that are not directly coursing through the rectus muscle may be injured during the muscle flap dissection, as Blondeel et al.6 showed in their studies. Unfortunately, often the use of synthetic mesh was necessary for closing the abdominal defect. However, back to the simple and logical approach: the breast is made of mammary glands and ducts suspended
in fat. Following a mastectomy the breast should be reconstructed by fat and skin alone without muscle sacrifice. The superficial inferior epigastric artery (SIEA) and vein are the nourishing pedicle for the free SIEA flap, which has been used for a wide variety of reconstructive purposes. Wood7 reported the pedicle SIEA flap for correction of burn contracture of the hand in 1863. Further indications for this flap were demonstrated by Hester8 for defects of the head, neck, and extremities after he examined the blood supply of the abdomen with emphasis on the SIEA. Several years later progressive hemifacial atrophy associated with Lyme disease in a child9 was treated with an SIEA-flap transfer. The author (RJA)10 used the SIEA flap for breast reconstruction in 1989 followed by Grotting11 in 1991. The idea to use cutaneous flap with direct cutaneous vessels as pedicle for breast reconstruction was continued by Arnez,12 who reported five successful cases. A variation of the SIEA flap is described in Buncke’s13 atlas of microsurgery: transplantation –replantation by the use of the bilateral inferior epigastric artery flap (BIEF). The BIEF needs an excessive pedicle dissection as it includes the three main systems for the abdominal perfusion: the deep inferior epigastric artery, the large perforators from the deep circumflex iliac artery,
and the SIEA. Following this short overview of the historical attempts to reconstruct the ideal breast we have to remember the principles of free flaps summarized by Taylor14: 1. The predictability of the vascular supply to the donor site 2. The suitability of the recipient vessels 3. The expertise employed in the microvascular procedure Therefore, in search of the perfect flap for breast reconstruction, the anatomy of the transplantated tissue is of major importance.

ANATOMY
The differentiation of the fat and skin perfusing vessels is well known since the early studies of Henle15 and Manchot.16 The musculocutaneous arteries arise from a large segmental muscular artery and supply the overlying muscle and a limited area of skin above it. This type of perfusion is most numerous in “fixed-skin” areas of the body such as the dorsum and the limbs. The direct cutaneous arteries pierce and run immediately above the deep fascia and supply a large area of skin such as the “loose skin areas” of the ventrolateral dorso, the hands, feet, head, and neck. The venous drainage of the fat layer is separated into a deep and superficial system. The deep system provides heat in comparison with the superficial system, which exchanges heat and transports large volume of blood. Concerning the previously postulated predictability of the vascular supply of a free flap, the direct cutaneous arteries offer a blood supply that allows a large or irregular contour of the flap design and are considered to be easier dissected. Taylor14 found the presence of 65% of his study of groin dissections in cadavers. As the SIEA varies in size and presence, the author (RJA)10 reviewed the predictability of these vessels in a large study of 100 cadaver dissections. Our study motivated us to use this flap for breast reconstruction as we found a consistency of 72% in dissected groins with an average size of 1.6 mm (range 0.75 to 3.5 mm) at the level of the inguinal ligament. At the point of origin the artery has an average diameter of 2.9 mm (range 2.0 to 4.0 mm). In 58% the artery is present on both groins. The artery lies lateral to the superficial inferior epigastric vein between the pubic tubercle and the anterior superior iliac spine. Vena comitantes course with the artery. In our study we found three variations of the origin of the SIEA. In 79% the SIEA and the SCIA arise from a common trunk of the femoral artery 2 cm below the inguinal ligament. The different variations of the artery are explained in Figure 1.



FLAP DESIGN AND OPERATIVE TECHNIQUE
Evaluation of the ideal patient depends on the adequate amount of abdominal fat, prior abdominal surgeries, and past medical history such as chemotherapy, radiation, or smoking. The last three factors increase the fragility of the dissected vessels. The flap design is drawn on the supine patient 1 day prior to surgery and depends on the Doppler location of the SIEA. Therefore, we use a handheld Doppler probe (5-Mz ultrasound stethoscope,
Doppler mode BF4B,Medasonics™), which allows us to verify the exact location of the SIEA and also the location of the perforators of the DIEA. In the 9% absence of the SIEA in both groins or in inadequately sized vessels we use the deep inferior epigastric artery perforator (DIEP) flap for breast reconstruction. The drawn flap design includes the SIEA markings caudal and extends cranial to the umbilicus. A standard abdominal pinch test is done to evaluate the amount of harvested tissue and to control the abdominal closure. Figure 2A shows the dissected SIEA and Figure 2B shows a harvested free SIEA flap. The background marks the pedicle. In the ideal situation a primary reconstruction of the breast is done, which offers the patient a “new breast” after skin-sparing mastectomy. The patient does not have to suffer from the emotional trauma of waking up without a breast and copes quicker and is more motivated than after a secondary breast reconstruction. The operation is undergone in a two-team approach. Meanwhile, the general surgeon excises the breast parenchyma and undergoes the sentinel lymph node biopsy with or without lymph node dissection; the plastic surgeon harvests the SIEA flap. The two operation teams stand contralateral and therefore do not disturb the dissection of each other. If the SIEA and vein are not acceptable the contralateral side is dissected. Following the mastectomy the internal mammary artery and veins16 as recipient vessels are dissected. The pectoralis major muscle is divided above the palpated third rib. The medial border of the muscle is incised cranial and caudal, which provides more room for the pedicle and prevents its compression. The perichondrium of the third rib is incised in an H pattern and carefully dissected with the freer and a rib stripper. The cartilage is cut laterally and exarticulated at the costosternal joint medially. The dorsal perichondrium is opened and the internal mammary artery and vein are prepared. The flap is weighed and the venous and arterial anastomosis are undergone microscopically. Postoperatively, the perfusion is checked clinically and with an implanted venous Doppler (Cook- Swartz Doppler Flow Probe™) as well as with a handheld Doppler (5-Mhz ultrasound stethoscope Doppler model BF4B,Medasonics®) at the marked point of the SIEA. About 3 months later the nipple is reconstructed under local anesthesia with an “arrow design,” and about 8 weeks later the areola is tattooed.

RESULTS
In our series of 85 cases since 1997 we have had excellent results with the SIEA flap for breast reconstruction. The 70 patients had an average age of 46 years, with the youngest at the age of 15 years and the oldest at the age of 70 years. Fifty-five patients suffered from ductal invasive carcinoma, six patients from ductal carcinoma in situ (DCIS), two patients from lobular carcinoma in situ (LCIS), one patient from inflammatory carcinoma, and two patients from medullary carcinoma. This flap technique was also used for autogenous augmentation in four other cases, which are demonstrated in the article “Management of Congenital Breast Deformities and Autogenous Breast Augmentation” found in this issue. In these cases the SIEA flap was used for an immediate contralateral augmentation following a breast reconstruction with a DIEP flap in a single patient and for esthetic augmentation because of congenital breast hypoplasia in three other patients. In 32 patients the breasts were immediately reconstructed after a skin-sparing mastectomy was performed. Thirteen patients underwent a bilateral reconstruction with SIEA flaps.

CASE REPORTS
We are presenting several typical breast reconstructions with SIEA flaps. The case reports demonstrate our three-stage reconstruction with the SIEA flap from immediate reconstruction to the nipple and areola reconstruction, immediate and secondary reconstructions, and bilateral reconstructions. Because of the previously mentioned inconsistency of the SIEA we often used the DIEP flap on one side and the SIEA on the other. Case Report 1 (Fig. 3)
This 48-year-old woman was diagnosed with invasive ductal carcinoma of the right breast. She did not want any implants and decided on an immediate reconstruction (Fig. 3A). Figure 3B shows her postoperative result with an SIEA flap about 14 day later. She still has some edema, which will be resorbed and gives the reconstructed breast a natural ptosis. Figure 3C demonstrates her final result after nipple reconstruction and areola tattooing. Case report 2 (Fig. 4)
A 55-year-old woman was diagnosed with ductal carcinoma of the right breast (Fig. 4A). Intraoperative dissection demonstrated adequate superficial vessels (Fig. 4B). The harvested flap weighed 848 g (Fig. 4C). The second intercostal perforator was selected as the recipient neurovascular bundle (Fig. 4D). Figure 4E shows the sensate SIEA breast reconstruction. Case Report 3 (Fig. 5) This 30-year-old woman is status post–bilateral mastectomy because of ductal carcinoma (Fig. 5A). Figure 5B illustrates the reconstruction with a right SIEA flap and a left DIEP flap status post– nipple reconstruction and tattooing. Case report 4 (Fig. 6)
A 16-year-old young woman presented with congenital hypoplasia of the left breast (Fig. 6A). The preoperative design avoids periumbilical incision. Figure 6B is 5 weeks post–submammary augmentation with a 329-g SIEA flap.

DISCUSSION
The principles of free flaps summarized by Taylor14 are fulfilled with the use of the SIEA flap. The predictability of the vascular supply to the donor site is demonstrated in a repeated study by the author (RJA)10 and by the clinical use of this flap for breast reconstruction and even for breast augmentation. The suitability of the recipient vessels is summarized in the report of Dupin et al.17 of 110 cases of the internal mammary artery and vein as a recipient site for free-flap breast reconstruction. We use the same technique and consider these vessels excellent recipients, which are easily dissected and provide reliable perfusion with consistency. The average diameter of the internal mammary artery and vein matches adequately with the diameter of the SIEA and SIEV. The expertise employed in the microvascular procedure depends on the learning curve of the surgeon.We think that sometimes the dissection of the DIEP pedicle is more demanding than the dissection of the pedicle of the SIEA, which is a direct cutaneous artery.Taylor14 summarizes that, in general flaps, designed on direct cutaneous arteries are easier to dissect and produce less morbidity than those designed on musculocutaneous arteries. The main advantage of the SIEA flap is that it does not require opening of the anterior rectus sheath and therefore does not harm the integrity of the abdominal wall. The risk of an abdominal hernia or bulge is nonexistent. The morbidity of the donor site is minimal as the muscles are not weakened. Donor site seroma has been the most frequent complication. The postoperative pain is even lower in comparison with the DIEP flap and much lower than in the TRAM flap. Kroll et al.18 compared the postoperative morphine use in free TRAM and DIEP flap patients. The morphine need evaluated by the use of a PCA pump was lower by half in the DIEP flap patients than in the TRAM flap patients. The advantages of autogenous breast reconstruction in comparison with implants are well known. Autogenous breast reconstruction provides a final breast reconstruction without implantrelated problems such capsule formation, dislocation, pain, or implant rupture, which lead to further surgeries. The advantages of the SIEA flap for breast reconstruction are multiple: (1) it provides soft tissue with comparable consistency and skin color to breast tissue. The transplantated tissue can be shaped individually and because of the perfusion by a direct cutaneous artery irregularly. (2) It avoids transfer or transplantation of a muscle pedicle such as in the pedicled or free TRAM flap. (3) It provides the patient an abdominoplasty closure, which is often desirable after multiple pregnancies. Because of the lower incision of the SIEA flap in comparison with the DIEP flap the esthetic outcome of the low abdominal scar is even more pleasing. The indications for the SIEA flap are significant soft tissue defects of the breast. These include not only oncological breast reconstruction but also breast augmentation. The SIEA is present in 72% and the common trunk in 79%10; therefore, this flap should be integrated in any approach to breast reconstruction.We agree with Arnez’s19 classification of the harvesting defects of the lower abdomen, which considers the pedicled TRAM flap to have the highest morbidity followed by the free TRAM flap and less morbidity with the DIEP flap. However, the SIEA flap has to be included in this evaluation as being the abdominal free flap with the lowest donor site morbidity.

CONCLUSION
In search of the perfect flap for breast reconstruction we consider the free SIEA flap the ideal procedure. It provides minimal donor site morbidity and allows the surgeon to switch to other procedures such as the DIEP flap if the vessels found at the time of surgery are inadequate. Because of our studies one can conclude that, in a given patient without previous abdominal surgery, one may find an SIEA of adequate size for anastomosis in 91%. The vessel can be traced to an equal- or largersized vessel in the majority of cases. The ideal patient would be of mild to moderate obesity without any previous abdominal surgery. We include this technique in any breast reconstruction as firstchoice flap followed by the DIEP and then by the GAP flap.

REFERENCES
1. Maxwell GP. Igino Tansini and the origin of the latissimus dorsi musculocutaneous flap. Plast Reconstr Surg 1980; 65:686–692 2. Mühlbauer W, Olbrisch R. The latissimus dorsi myocutaneous flap for breast reconstruction. ChirPlast 1977; 4:27–34 3. Holmstrom H. The free abdominoplasty flap and its use in breast reconstruction. Scand J Plast Reconst Surg 1979;13: 423–427 4. Hartrampf CR, Schelan M, Black PW. Breast reconstruction with a pedicled transverse abdominal island flap. Plast Reconst Surg 1982;69:216–225 5. Grotting JC, Urist M, Maddox W, et al. Conventional TRAM versus free microsurgical TRAM flap for immediate breast reconstruction. Plast Reconstr Surg 1989;83: 828–841 6. Blondeel N, Vanderstraeten GG, Monstrey SJ, et al. The donor site morbidity of free DIEP flaps and free TRAM flaps for breast reconstruction. Br J Plast Surg 1997;50: 322–330 7. Wood J. Extreme deformities of the neck and forearm. Med Chir Trans 1863;46:151 8. Hester TR. Blood supply of the abdomen revisited with emphasis on the superficial inferior epigastric artery. Plast Reconst Surg 1984;74:657–670 9. Stern H. Progressive hemifacial atrophy associated with Lyme disease. Plast Reconst Surg 1992;90:479–483 10. Allen R. The superficial inferior epigastric artery free flap: an anatomic and clinical study for use in reconstruction of the breast. In: Proceedings of the Xth Annual Meeting of the Southeastern Society of Plastic and Reconstructive Surgeons. Kiawah, SC, June 3–7, 1990 11. Grotting J. The free abdominoplasty flap for immediate breast reconstruction. Ann Plast Surg 1991;27:351–354 12. Arnez ZM. Breast reconstruction using the free superficial epigastric artery (SIEA)-flap. Br J Plast Surg 1999;52: 276–279 13. Buncke H. Bilateral inferior epigastric flap (BIEF). In: Buncke H, ed. Microsurgery: Transplantation-Replantation. An Atlas-Text, 1st ed. Philadelphia: Lea & Febiger; 1991:167–186 14. Taylor GI. The anatomy of several free flap donor sites. Plast Reconst Surg 1975;56:243–256 15. Henle JFG. Handbuch der Gefä_lehre des Menschen im Handbuch der Systematischen Anatomie des Menschen, 1. Auflage, Vivweg, Braunschweig, 1869 16. Manchot C. Die Hautarterien des Menschlichen Körpers, 1. Leipzig: Auflage F. C.W. Vogel; 1889 17. Dupin CL, Allen RJ, Glass CA, Bunch R. The internal mammary artery and vein as a recipient site for free-flap breast reconstruction: a report of 110 consecutive cases. Plast Reconstr Surg 1996;98:685–689 18. Kroll SS, Sharma S, Koutz C, Lanstein HN, et al. Postoperative morphine requirements of free TRAM and DIEP flaps. Plast Reconst Surg 2001;107:338–341 19. Arnez ZM. Rational selection of flaps from the abdomen in breast reconstruction to reduce donor site morbidity. Br J Plast Surg 1999;52:351–354

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