Bipedicled SIEA Flap with Deep Inferior Epigastric Artery and Vein Grafts for Breast Reconstruction

Summary:

A superficial inferior epigastric artery (SIEA) flap can be an alternative to a deep inferior epigastric artery perforator (DIEAP) flap in cases where SIEAs are relatively well developed. Although an SIEA flap is less invasive than a DIEAP flap, the pedicles of the former are anatomically shorter, making it more difficult to choose recipient vessels when bilateral SIEAs are necessary. A 45-year-old female diagnosed with cancer of the left breast underwent mastectomy (specimen weight: 750 g) and immediate two-stage breast reconstruction using a free abdominal flap with bilateral pedicles was planned. Preoperative computed tomographic angiography showed that the bilateral DIEAPs in the flap were less than one millimeter in diameter, whereas the bilateral SIEAs were well developed enough for us to opt for a double-pedicled stacked SIEA flap. After the double-pedicled SIEA flap was elevated, folded, and temporarily placed in the subcutaneous pocket, the pedicle length on one side was found to be insufficient. Therefore, portions of the right composite deep inferior epigastric artery (DIEA) and vein (DIEV) grafts (roughly 7 cm) were collected from a short fasciotomy and anastomosed to the peripheral ends of the right SIEA and SIEV, respectively. Following this, the left SIEA and SIEV were antegradely anastomosed to the internal mammary artery and vein (IMA/IMV), while the DIEA/DIEV grafts were retrogradely anastomosed to the IMA/IMV, respectively. We recommend the proactive use of this method, as pedicle extension using the DIEA/DIEV grafts enables a higher degree of freedom in unilateral breast reconstruction using bilateral SIEA flaps.

Postmastectomy breast reconstruction using a deep inferior epigastric artery perforator (DIEAP) flap is widely accepted as the gold standard for acquiring sufficient abdominal tissue with minimal invasion to the donor site.¹ Among other reconstruction options such as muscle-sparing transverse rectus abdominis musculocutaneous flaps, superior gluteal artery perforator flaps, or double transverse upper gracilis flaps, the superficial inferior epigastric artery (SIEA) flap is a good alternative to a DIEAP flap in cases where SIEAs are more developed than DIEAPs. Although an SIEA flap is less invasive as it does not require dissection of abdominal wall muscle, given the anatomically shorter pedicles relative to those of a DIEAP flap, the SIEA flap is inferior to a DIEAP flap in its ease of flap placement.^2,3 When bilateral SIEAs are necessary, this may complicate recipient vessel selection.

The present case of breast reconstruction used composite deep inferior epigastric artery (DIEA) and deep inferior epigastric vein (DIEV) grafts to lengthen the pedicle and overcome this disadvantage in a double-pedicled SIEA flap.

CASE REPORT

A 45-year-old woman diagnosed with left breast cancer underwent mastectomy, and immediate two-stage breast reconstruction was planned. Following resection of 750 grams of mammary gland, a tissue expander was inserted and gradually filled with 850 mL of saline solution. Breast reconstruction using a free abdominal flap with bilateral pedicles was planned for 11 months postmastectomy.

Preoperative computed tomographic angiography revealed bilateral DIEAPs at the penetration site of the fascia of less than 1 mm diameter. Meanwhile, bilateral SIEAs were developed enough for us to opt for a double-pedicled stacked SIEA flap. (See figure, Supplemental Digital Content 1, which shows preoperative computed tomographic angiography, http://links.lww.com/PRSGO/C143.) However, concerned about insufficient pedicles when one pedicle was anastomosed antegradely to the internal mammary artery (IMA) and retrogradely to the internal mammary vein (IMV), we planned to use DIEA/DIEV grafts as interpositional grafts to lengthen the pedicle.

A double-pedicled SIEA flap measuring 36 cm and 11 cm in width and height, respectively, was raised from the lower abdomen. After removing the fourth rib cartilage to expose the IMA and IMV, the flap was folded and temporarily placed in the subcutaneous pocket. As expected, pedicle length on the right side was insufficient. Therefore, portions of the right DIEA and DIEV grafts (roughly 7 cm each) were collected by fasciotomy (roughly 5 cm) along the ipsilateral inferolateral rectus sheath and anastomosed to the peripheral ends of the right SIEA and superficial inferior epigastric vein (SIEV) with 9-0 nylon sutures and a 1.5-mm coupler, respectively (Fig. 1A). Next, the left SIEA and SIEV were antegradely anastomosed to the IMA and IMV with 9-0 nylon sutures and a 2.5-mm coupler, respectively. DIEA and DIEV grafts were retrogradely anastomosed to the IMA and IMV with 9-0 nylon sutures and a 2.0-mm coupler, respectively (Fig. 1B). After trimming, the flap (730 g) was arranged vertically and folded at the left side of the flap to form a breast mound (Fig. 2A, B). Total surgery time was 8 hours and 25 minutes.

Fig. 1.

Intraoperative view. A, 7-cm portions of the right DIEA/DIEV grafts were collected and anastomosed to the peripheral ends of the right SIEA/SIEV. The tip of the forceps indicates the site of vascular anastomosis. B, Left SIEA/SIEV were antegradely anastomosed to IMA/IMV (yellow arrow), and the DIEA/DIEV grafts were retrogradely anastomosed to IMA/IMV (white arrow). C, Arrowhead: anastomosis between right SIEA/SIEV and DIEA/DIEV grafts. Blue area: DIEA/DIEV grafts.

Fig. 2.

Schematic of flap arrangement. After a portion of the flap was trimmed slightly (A), the flap was arranged vertically and folded at the left side of the flap to form a breast mound (B). When the flap is folded in the middle (C), the distance between the bilateral SIEA/SIEVs is short; this increases when folded on either side, requiring grafts (B).

The patient had no postoperative complications and was discharged 14 days after surgery. Fourteen months postoperatively, the patient remains free of any serious complications such as flap necrosis or abdominal hernia. (See figure, Supplemental Digital Content 2, which shows postoperative view at 14 months, http://links.lww.com/PRSGO/C144.)

DISCUSSION

Unilateral reconstruction of large breasts often indicates a free abdominal flap with bilateral pedicles. Although rare, in some like the present case, both sides lack significant DIEAPs, and SIEA and SIEV often develop compensatorily. Although SIEA flaps allow for transplantation of large volumes of tissue in a short time without fascial incision, their anatomy renders the pedicles shorter than those of DIEAP flaps. This is not problematic for unilateral pedicles with sufficient flap volumes or when one bilateral pedicle is a DIEA/DIEV. However, when bilateral pedicles are SIEA/SIEVs, choosing recipient vessels can become problematic. Specifically, given the challenges of anastomosing one to internal thoracic vessels and another to thoracodorsal vessels, surgeons are extremely restricted with flap placement options.

Several studies have reported unilateral breast reconstruction using bilateral SIEA flaps. Although Malata and Rabey⁴ do not specify, we assume that bilateral SIEA/SIEVs were anastomosed to IMA/IMVs antegradely and retrogradely, respectively, in the immediate reconstruction. Murray et al⁵ also folded the flap and anastomosed the bilateral pedicles antegradely and retrogradely to IMA/IMVs in the secondary reconstruction. Francis et al⁶ anastomosed the right SIEA/SIEV to the perforator on the pectoralis major muscle and the left SIEA/SIEV to the IMA/IMV. None of these mention graft use.

Although our case reflects the reconstruction method of Murray et al, it differs in that the distance between the bilateral SIEA/SIEVs was increased when the flap was arranged and folded at the left side of the flap, as a vertically long breast mound was required (Fig. 2B, C). While cartilage from multiple ribs could be removed to widen the IMA/IMV exposure, the superior and inferior pedicles would be anastomosed to IMA/IMV antegradely and retrogradely, respectively, increasing the risk of pedicle kinking.⁷ Anastomosing each pedicle to the IMA/IMV in a “criss-cross” fashion⁷ required extension of the unilateral pedicle by grafting. Use of DIEA/DIEV grafts enabled relatively easy vascular anastomosis without excessive tension on the pedicles.

DIEA/DIEV grafts can be collected from the same surgical field with a 4–5 cm fasciotomy, eliminating surgical invasiveness such as intramuscular dissection or nerve injury.^8,9 Compared with other vein grafts, DIEA/DIEV grafts are physiologically natural, reducing the risk of arterial thrombosis.¹⁰ Although an additional anastomosis is required, anastomosis between SIEA/SIEV and DIEA/DIEV grafts is easily performed on the table. Cho et al⁸ and Gassman et al¹⁰ reported active use of DIEA/DIEV grafts in cases of unilateral SIEA flaps, primarily to overcome differences in pedicle diameter, thereby reducing the risk of thrombosis; their criterion for graft use was a difference in diameter of 1 mm or more. Therefore, even in a double-pedicled SIEA flap such as that of the present case, the use of DIEA/DIEV grafts could extend the pedicle and reduce the risk of thrombosis, even on one side.

CONCLUSION

In unilateral breast reconstruction using bilateral SIEA flaps, a higher degree of freedom in reconstruction is made possible by extending the pedicle length using DIEA/DIEV grafts.

ETHICAL APPROVAL STATEMENT

All procedures conformed to the principles set forth in the Declaration of Helsinki. This study was approved by the Ethics Committee of Osaka University.

PATIENT CONSENT STATEMENT

Written informed consent to publish personal and medical information was obtained from the patient.