Internal Mammary Artery Perforator Flap for Immediate Volume Replacement Following Wide Local Excision of Breast Cancer

Patients

From January 2011 through January 2015, 256 oncoplastic WLEs were performed in 249 women with ductal carcinoma in situ (n=56), invasive ductal carcinoma (n=180), or benign tumours (n=13). Breast reduction techniques were applied in 172 of these 249 women, whereas an immediate tissue replacement technique was used in the remaining 77 women. Two women underwent bilateral operations, and 5 others underwent repeated WLE and tissue displacement after an initial non-radical WLE combined with tissue displacement. We used the IMAP flap to replace a mean weight of 46.5 g (median, 36.0 g; standard deviation [SD], 30.1 g) of excised medial breast tissue in 12 non-smoking women with a mean age of 56.1 years (median, 55.7 years; SD, 6.2 years) and a mean body mass index of 24.5 kg/m² (median, 23.2 kg/m²; SD, 3.9 kg/m²) (Table 1).

Table 1.

Characteristics of 12 women who underwent wide local excision and oncoplastic reconstruction using an IMAP flap

Preoperative planning

Preoperative perforator mapping was performed with a unidirectional Doppler probe (8 Hz) with the patient in the supine position. The perforator of the fourth or fifth ipsilateral intercostal space was marked on the skin, approximately 6 to 11 mm lateral to the sternal border [10]. The superior border of the flap was projected in the inframammary fold to assure that the flap would contain abdominal, rather than mammary tissue (Figs. 1, 2). The width and inferior border of the skin pedicle flap were established by pinching the inframammary skin and subcutis between the thumb and index finger. The length of the flap could reach the anterior axillary fold, but was preoperatively designed and intraoperatively adjusted depending on the replacement volume needed [11].

Fig. 1.

Preoperative design of the IMAP flap

The design was made with the patient in supine position. X indicates the location of the tumour. IMAP, internal mammary artery perforator.

Fig. 2.

Design of the IMAP flap after WLE

The small o indicates the IMAP. The large O indicates the WLE defect. IMAP, internal mammary artery perforator; WLE, wide local excision.

Surgical technique

The women underwent surgery in the supine position with both arms abducted at 90°. Immediately following the WLE and possible axillary node dissection, the skin was incised as planned. The flap was raised from its lateral edge overlying the external oblique muscle towards the rectus fascia, thus approaching the IMAP. Medially, we preserved a skin pedicle in the first 6 women. Propeller flaps were applied in the latter 6 women. Subsequently, the abdominal, caudal edge of the donor flap was raised at a suprafascial level. This edge was then advanced cranially over a vacuum drain towards the inframammary fold using ample subcutaneous quilting sutures. After the lower incision line was situated in the inframammary fold in this way, we fixed it to the fascia with vicryl 2-0 sutures to prevent caudal displacement of the inframammary fold.

The flap was rotated 90° and tunnelled from the inframammary fold into the medial mammary defect. The IMAP flap was de-epithelialized as needed and fixed in the recipient site with vicryl 3-0 sutures in order to prevent dead space (Figs. 3, 4). Finally, the skin was closed intracutaneously (Figs. 5, 6).

Fig. 3.

Rotation and tunneling

The de-epithelialized IMAP flap was rotated and tunnelled from the inframammary fold into the medial mammary defect. IMAP, internal mammary artery perforator.

Fig. 4.

Rotation and tunneling

Rotation and tunnelling of the de-epithelialized propeller IMAP flap. The de-epithelialized propeller IMAP flap was rotated and tunnelled from the inframammary fold into the mediocranial mammary defect. IMAP, internal mammary artery perforator.

Fig. 5.

Result immediate postoperative

The donor site after intracutaneous closure of the skin.

Fig. 6.

Result immediate postoperative

The donor site after intracutaneous closure of the skin.

The women were discharged from hospital on the first day after surgery. The drain was left until its production was less than 20 mL/24 hour. Three weeks postoperatively, all patients were seen at our outpatient clinic to evaluate the healing of the breast in order to treat possible complications before adjuvant radiotherapy was started 4 weeks postoperatively.

Follow up and cosmetic evaluation

Further postoperative assessments were performed routinely at 3 and 6 months after surgery (Fig. 7). Any additional conservative or surgical treatment was noted. All women evaluated the cosmetic outcome and position of the nipple on a scale from 0 (very unsatisfactory) to 10 (very satisfactory), after a median follow-up of 35 months (SD, 1.2 months). They were asked about volume asymmetry compared to the non-operated contralateral breast and about possible pain in the reconstructed breast or donor area. Last, they indicated whether they would choose the oncoplastic approach with an IMAP flap reconstruction again in a similar situation.

Fig. 7.

Result at 6 months after surgery

General advantages and disadvantages of oncoplastic reconstruction after WLE

The ultimate goal of oncoplastic WLE is to allow relatively large-volume resections with free margins and fewer re-excisions and additional mastectomies than can be obtained with standard WLE [12]. It allows restoration of breast shape and volume before radiation therapy is started. This results in more patients being satisfied with the cosmetic outcome [12,13]. Consequently, it may prevent secondary, post-radiotherapy surgical correction of mammary malformations [1,14]. Although this combined oncoplastic approach has extended the indications for BCT, its true value for the prevention of local recurrence remains to be determined [12]. Although many guidelines and extensions of indications have been suggested [1,15-17], there are no standardized practices or guidelines regarding the use of oncoplastic reconstruction [18].

A disadvantage of volume replacement techniques may be donor site morbidity and flap failure [7]. Furthermore, oncological re-operations may be more difficult in cases where the initial excision turns out to have been pathologically non-radical [12].

Development of the IMAP flap

Starting in 1917, IMAP-based flaps have been used, mostly for head and neck reconstruction [19]. The ability of the lower perforating branches of the internal mammary vessels to serve as the vascular pedicle of a true island flap was proven by Kalender et al. [20] when they introduced the use of the IMAP flap for post-burn mammary correction in 2000. Subsequently, the use of this flap was described for secondary contralateral breast reconstruction [20-22] and the reconstruction of anterior chest wall defects following ablative surgery [23,24]. During preoperative planning, it is not always clear whether the most inferior IMAP or the most superior epigastric artery perforator (SEAP) is included in the flap. Although the potential use of the IMAP or SEAP flap [23,25] for immediate ipsilateral oncoplastic breast reconstruction has been suggested, no reports on this use have been published so far.

Potential limitations of our methodology

Before we discuss the clinical implications of our observations, some potential limitations of our report need be addressed. The small number of patients may be explained by the limited incidence of tumours in the medial quadrants of the breast. Still, our mean follow-up of 2.6 years indicates that the use of the IMAP flap for this indication is not just feasible, but successful as well.

A second limitation may be that the successful use of this flap depends on cooperation between an oncological surgeon and a reconstructive surgeon and on both their personal experiences [1]. Hence, our experience may not be easily extrapolated to other clinics, despite the generally increasing interest in oncoplastic techniques.

Clinical implications of our observations

In this series, we replaced the resected tissue of oncologic specimens of a maximum of 125 g (range, 18–125 g; SD, 30.1 g) (Table 1). This, however, did not constitute the maximum possible weight of the IMAP, which obviously depends on the body mass index and superior abdominal skin laxity of the patient. In cases where this maximum volume proves insufficient to replace all tissue loss, immediate or secondary additional lipofilling may be performed. Furthermore, the perforator itself may be dissected in cases where additional advancement of the flap is needed, although this did not occur in our series [19].

We observed no flap loss and the overall satisfaction of our patients was good. Adhesiolysis of the scar and dog-ear correction at the donor site were the main reasons for re-operation. To prevent dog-ear corrections in the latter half of this series, we incised the skin pedicle of the flaps and applied the flaps as true propeller flaps in patients number 7 through number 12 (Table 1). Although the mean breast cosmesis scores among these latter 6 patients (mean, 8.67; SD, 0.58) were more favourable than those among the 6 patients in whom a pedicled flap was applied (mean, 7.63; SD, 1.19), this difference did not reach statistical significance (P=0.36). We advise the liberal application of quilting sutures when advancing the abdominal edge of the donor site towards the inframammary fold in order to reduce possible traction on this fold and the donor scar.

In conclusion, we chose to use the IMAP flap for medial breast defects because it is a reliable fasciocutaneous local flap with good cosmetic outcomes. The favourable results of using the IMAP flap in breast-conserving surgery widen the applications of this flap, which may lead to a further increase of indications for breast-conserving surgery. Although donor site revision often proved necessary in the first half of this series, we showed this to be easily preventable in the latter half.