THE PRESERVATION OF A SPARE HEMI-ABDOMINAL FLAP IN UNILATERAL BREAST RECONSTRUCTION WITH ABDOMINAL FREE FLAP IN HIGH RISK PATIENTS

INTRODUCTION

Autologous free tissue transfer for breast reconstruction is a well-established and reliable procedure. Breast reconstruction with free abdominal flaps enables a plastic surgeon to obtain a natural shape of the reconstructed mound and stable long term results (2, 3). The donor site morbidity is usually acceptable and well tolerated, especially when a free muscle sparing-TRAM or a DIEP flap is used (5, 8). However, selection of the patient is very important, and the possibility of other reconstructive options should be taken into account based on the patient’s preferences, co-morbid conditions, oncology status, potential size of the reconstructed breast and previous surgeries in the abdominal area (1).

Prophylactic bilateral skin sparing or subcutaneous mastectomy with immediate reconstruction is a surgical option considered by many patients with high risk of developing breast cancer. BRCA mutations, very strong familial history and/or multifocal pre-malignant changes in the breast parenchyma, along with contra-lateral breast cancer, are some of the reasons why women opt for prophylactic mastectomies. Both autologous and implant-based breast reconstruction is available to these patients. Many patients prefer reconstruction of the breast with autologous tissue (4, 7, 9–11). Patients with adequate abdominal tissue and small/medium breast size are able to have the breast reconstructed with a hemi-abdominal flap alone. This enables symmetric reconstruction utilizing the abdominal flap composed of only vascular areas I and II of the DIEP flap. Usually the peripheral zones III and IV are discarded. However, it is possible to bank the unused hemi-abdominal flap for later use instead of discarding it. This “spare” flap could then potentially be used for reconstructing the contra-lateral breast in patients who later develop breast cancer in that breast, or be used as a salvage flap for a failed primary reconstruction. We describe this surgical approach to unilateral breast reconstruction in patients with unilateral breast cancer; patients who are at high risk for developing contra-lateral breast cancer but reluctant to undergo simultaneous prophylactic mastectomy of the opposite breast; or patients for whom the risk of free flap failure is high.

MATERIAL AND METHODS

We describe the technique of preservation of a spare hemi-abdominal flap in two patients. Both patients underwent unilateral mastectomy with immediate reconstruction and were at high risk of developing breast carcinoma in the opposite breast; however, they opted not to have a prophylactic mastectomy of the unaffected breast. They also had ample abdominal tissue to reconstruct the affected breast with only half of the abdominal tissue. Instead of discarding zones III and IV, the contra-lateral, unused hemi-abdominal flap was banked. This portion of the flap was deepithelialized and buried under the abdominal closure. This “spare” flap could potentially be used in case of future requirement for contra-lateral breast reconstruction or as a bailout flap. The patients were preoperatively informed about the possibility of developing a visible asymmetry of their abdomen caused by the buried extra tissue. It was explained to them that, if desired, liposuction could be performed in future to achieve symmetry.

Case No. 1

Patient 1 was a 55-year-old female who underwent a right subcutaneous mastectomy for Grade 1 ductal carcinoma in situ and immediate unilateral breast reconstruction (Fig. 1). The patient was at high risk for the development of a metachronous contra-lateral breast carcinoma due to her strong familial history. Despite counselling, she opted not to have a prophylactic contra-lateral mastectomy. A right DIEP hemi-abdominal flap was harvested in the described manner for bilateral reconstructions (Fig. 2). The blood supply was based on two lateral row perforators. The flap was transferred to the recipient site, and the breast was reconstructed. Microsurgical anastomosis was performed to the internal mammary artery and vein in the 4^th inter-costal space. The unused left hemi-abdominal flap was de-epithelialized and buried underneath the usual abdominoplasty closure (Fig. 3 a–c).

At the end of the surgery the flap looked pale, with slow capillary refill. On re-exploration there was visible and palpable flow through both arterial and venous anastomoses. The pedicle did not show any signs of thrombosis, and no obvious damage to the perforators was observed. Vasospasm of the microcirculation was deemed the problem, and we administered Rheodextran 10% (Infusia, Czech Republic) in continuous infusion (30 ml per hour). During immediate postoperative care the circulation in the flap continued to show signs of ischemia. On the second postoperative day we surgically explored the anastomoses. Both arterial and venous anastomoses were patent, and detailed observation of the pedicle did not show any signs of damage or thrombosis. Persistent signs of ischemia forced us to perform a second flap exploration on the third postoperative day. This time the flap was removed after it was established that there was no microcirculation despite a patent pedicle artery and vein. There was, however, arterial thrombosis of both of the perforators distal to their take-off from the main pedicle. The specimens taken from the flap and different parts of the pedicle vessels were sent for histological examination, which revealed thrombosis of small vessels in the periphery of the flap, necrotizing vasculitis and necrosis of the sweat glands. As the stem of the pedicle was thrombus free and the main anastomoses of the deep inferior epigastric vessels to the intercostal vessels were patent, we left the main vessels of the flap pedicle in situ, and they served as vascular grafts. Breast reconstruction was subsequently accomplished using the buried contra-lateral hemi-abdominal flap. During harvest of the bailout flap we encountered large diameter superficial inferior epigastric vessels and extremely small calibre perforators from the deep system. We therefore decided to raise this flap on the superficial system. The vessels were anastomosed end-to-end to the original flap’s preserved deep inferior epigastric vessels in the chest.

The patient’s recovery after the second procedure was uneventful, and she was discharged on postoperative day #6. A seroma in the medial upper quadrant of the abdomen did develop, and it was aspirated on the 14^th postoperative day. Follow up at 4 months showed good symmetry of the reconstructed breast and satisfactory appearance (Fig. 4).

Case No. 2

Patient 2 was a 63-year-old active smoker who had a right lumpectomy for stage 2 lobular multicentric breast cancer in January 2005. She subsequently underwent adjuvant radiation and chemotherapy. In January 2007 the patient was referred to us for possible bilateral mastectomy and breast reconstruction. However, she was not willing to undergo a prophylactic mastectomy of the uninvolved left breast. After discussion she agreed to have the unused hemi-abdominal flap buried for potential future reconstruction. As the patient had ample abdominal tissue, only the right DIEP hemi-abdominal flap was used for the reconstruction of the right breast. The internal mammary vessels in the 4^th intercostal space were used as recipient vessels for the flap. The left hemi-abdominal flap was de-epithelialized and advanced centrally to maintain symmetry. The abdominal closure was achieved with the abdominoplasty flap thinned over the underlying buried tissue to decrease the appearance of a bulge. Her breast reconstruction healed uneventfully; however, the abdominal wound was complicated by skin necrosis in the midline below the umbilicus, where aggressive thinning had been undertaken. The 7x12 cm necrosis was excised one month after the reconstruction, and the defect was covered with a split thickness skin graft which healed well.

DISCUSSION

Our experience with free abdominal flaps began in 1992 and is so far based on more than 500 abdominal free tissue transfers. These include TRAM flaps, DIEP flaps and SIEA flaps. Our data shows that our total flap failure rate is 3%, comparable to published data (6, 11, 12).

In the patients described in our article the “spare hemi-abdominal flap” was buried under the abdominoplasty closure, on the basis that it might be possible to use it in case of development of a contra-lateral breast cancer requiring reconstruction, or as a bailout flap in the event of flap failure. This approach saves a patient from another remote donor site defect. We feel that the original flap loss in patient 1 was secondary to microcirculation failure within the flap. This phenomenon has already been described in 1987 using an experimental rodent model (13). We think that in this case the prolonged vasospasm inside the flap most likely led to the subsequent thrombosis of small vessels, despite patency of the main pedicle for three days. The continued patency of the main vessels may have been a result of persistent circulation through open A-V shunts in the pedicle of the DIEP flap. The bailout flap used in this patient was based on the superficial system, because the significantly small size of the perforators from the deep epigastric vessels would probably have forced us to harvest a “mini TRAM” flap, with its associated higher abdominal wall morbidity.

In the case of Patient 2, the flap healed uneventfully, and therefore the “spare” hemi-abdominal flap did not have to be used immediately. However, if required in the future, it is available for reconstruction. Central advancement of the flap under the abdominal closure was performed, to prevent an asymmetric bulge in the lateral abdominal wall. The necrosis of the central abdominal flap was a complication most likely caused by excessive tension on closure, aggressive flap thinning, and her history of smoking. Whether the extra tissue buried under the central portion of the flap exacerbated the situation is certainly a possibility; however, this is a known complication even in standard abdominoplasty closures, especially in smokers.

We believe the following clinical scenarios may benefit from having the hemi-abdominal flap preserved:

• Patients with high risk of contra-lateral breast cancer who do not wish to have simultaneous prophylactic contra-lateral mastectomy and reconstruction. This “spare flap” can avoid added donor site deformity if future reconstruction of the opposite breast is warranted.
• If there is a concern in the operating room about the reliability of the original unilateral breast reconstruction or the patient is at high risk for flap failure in the postoperative period.
• Banking this “spare” hemi-abdominal flap might also be useful for less experienced microsurgeons to have a possible bailout in case of problems.

This technique has some obvious limitations and drawbacks. It is suitable only in patients who have a relative abundance of abdominal tissue compared to the amount of tissue required for breast reconstruction, and it is ideal only in patients who undergo skin sparing/subcutaneous mastectomies. One has to de-epithelialize the tissue prior to burying, and therefore this limits the clinical indications in which it is used for future breast reconstructions. It would ideally be suited only in mastectomies that retain all or most of the skin envelope (subcutaneous or skin sparing mastectomies). If one needed to use the flap in a situation where skin coverage was also required (simple mastectomy), a full or split thickness skin graft to the de-epithelialized flap would be an option, although this would negatively impact the aesthetic result. Another option would be to harvest the “spare” flap with the overlying abdominal skin, although abdominal closure may become difficult requiring a skin graft at the donor site. Probably, where applicable, the best result would be obtained by staged expansion of the chest wall skin and subsequent use of the “spare” hemi-abdominal flap for volume fill. Thus the benefit of using autologous tissue instead of a permanent implant is maintained.

The possible donor site asymmetry and bulge is another potential disadvantage of this technique which the patient must be willing to accept. This asymmetry can be reduced by advancing the flap centrally, thus balancing the appearance. One must be cognisant of the potential necrosis of the abdominal flap if aggressive thinning is undertaken to decrease the appearance of the bulge, which may require surgical debridement and possible skin grafting with resultant donor site morbidity and poor aesthetic outcome. Liposuction of the area can always be performed if this asymmetry or bulge is of great concern to the patient.

CONCLUSIONS

We present a useful concept, based on our early experience with two cases, of burying the unused hemi-abdominal flap in unilateral breast reconstructions that can be accomplished by using solely the contra-lateral abdominal flap. The buried tissue can serve as a “spare” flap (DIEP, TRAM or SIEA) in high risk patients who may need future contra-lateral breast reconstructions, or as a bailout flap in the case of original flap loss. The use of the buried flap is best suited for patients undergoing skin sparing/subcutaneous mastectomies, and patients must be willing to accept a certain degree of abdominal wall asymmetry and/or bulge.

Abbreviations

DIEP flap – Deep Inferior Epigastric artery Perforator flap

TRAM flap – Transverse Rectus Abdominis Musculocutaneous flap

SIEA flap – Superficial Inferior Epigastric Artery flap

Acknowledgment

All the authors listed above contributed to the writing of the manuscript or assisted in the surgeries. The idea of the surgery comes from the senior author Jiri Vesely, and the surgeries were performed by him. This work was supported by the grant IGA-MZCR Nr. 8368-5.

Address for correspondence:

Prof. Jiri Vesely, M.D.

Clinic of Plastic and Aesthetic Surgery

Berkova 34

612 00 Brno

Czech Republic

E-mail: jiri.vesely@fnusa.cz