Successful breast reconstruction using acellular dermal matrix can be recommended in healthy non-smoking patients

Breast cancer survival seems to be increasing despite a more conservative surgical approach in oncologic breast surgery [1]. Preservation of aesthetically important units is of paramount importance, and skin- or even nipple-sparing mastectomies are becoming the standard of care depending on the tumour extent. Post-ablative reconstruction of the breast has thus become a parallel primary goal of modern breast cancer therapy, where oncologic and reconstructive objectives go hand in hand. Immediate breast reconstruction offers an aesthetical and psychological advantage to the patients [2].

The use of autologous tissue has been the reconstructive gold standard, among others due to the disappointing longevity of implant-based reconstructions as well a high rate of complications and revisions [3]. How-ever, implant-based immediate breast reconstruction seems to have gained popularity during the past decade. An important factor is the introduction of acellular dermal matrix (ADM) as well as fat grafting [4]. The ADM was first introduced in the 1990s for burn wound management [5] and later in 2003 reported to be beneficial in aesthetic breast surgery as well [6]. Breuing & Warren described a hammock extension to the subpectoral pocket with ADM in 2005 [7]. Subsequently, the technique has been widely adapted and modified by surgeons worldwide with evermore reports of its use and debates on its value or benefits [8]. We present Scandinavia’s first series of immediate alloplastic breast reconstruction with ADM.

MATERIAL AND METHODS

We collected data on 76 immediate breast reconstructions in 59 women with a median age of 51 years (range 30-70 years) using implant-based reconstructions in combination with an ADM. The procedures were performed at the Telemark Hospital in Norway and at Vejle Hospital in Denmark between June 2011 and January 2013. Patient data were recorded in a standard fashion and collected retrospectively. The median follow-up period was 326 days (range 68-624 days). Data on body mass index (BMI), smoking habits and relevant co-morbidity in the form of hypertension and diabetes were collected along with information of adjuvant chemo-, radiation and hormone therapy following the mastectomy. The indication for breast reconstruction was prophylactic and oncologic.

The reconstructions were carried out in immediate conjunction with a skin or nipple sparing mastectomy using an implant in combination with a sheet of Strattice, a porcine-derived ADM, to form an internal bra. The operative technique for immediate breast reconstruction was standardised as follows: the mastectomy was performed by the breast surgeon aided by a tumescent hydrodissection followed by subcutaneous dissection using a pair of scissors. A pocket was then dissected between the pectoralis major muscle and the chest wall using a monopolar cautery from lateral to medial and upwards releasing the inferomedial insertion. Following thorough rinsing of the ADM in three sets of sterile, isotonic saline baths for at least five minutes, the sheet was applied to the cavity. The inferomedial corner of the ADM was rounded off with scissors for a better fit before it was sutured along the new inframammary fold, the cut edge of the pectoralis major and along the anterior axillary line upwards laterally using a running 2-0 mono- or polyfilament resorbable suture. The implant was placed in the pocket under the ADM and the pectoralis major muscle. Implant selection was based on the breast footprint and mastectomy specimen weight. An expander or Becker type implant was used if the patient had a compromised or thin skin flap. In those cases, the expander was filled to a safe extent without causing tension on or compromising the overlying skin. Two drains were then placed, one within the implant pocket and one between the mastectomy skin and neocapsule. The vitality of the mastectomy skin flaps was evaluated for signs of perfusion, skin edge bleeding and capillary response and debrided accordingly prior to skin closure. The drains were left in place until the draining volume was less than 10-20 ml per day. All patients received a prophylactic dose of intravenously administered antibiotics for the first 24 hours, followed by oral antibiotics four times a day until drain removal. Mobility was encouraged. Application of a compressive bra and a breast band was used if indicated to guard elevation of the implant.

The patient follow-up parameters registered were: 1) skin- or fat necrosis, 2) wound dehiscence, 3) infection, 4) seroma and 5) success/failure of reconstruction.

RESULTS

We performed immediate breast reconstruction in a total of 59 patients. The indication was oncologic in 49 cases and prophylactic in ten cases. A skin-sparing mastectomy was chosen in 50 patients and a nipple-sparing mastectomy (NSM) in nine patients (Table 1). The average BMI was 24 kg/m2 (range 18-36 kg/m2). Active smoking was the most common co-morbidity registered in 19 patients, 11 had hypertension and two were diabetics.

The total number of reconstructed breasts was 76; 38 left-sided and 38 right-sided. The median implant size was 370 cc, (range 200-620 cc). We used six expanders, 19 Becker, eight round silicone and 26 anatomic silicone implants (Table 1). A total of 65 pieces of ADM sized 8 × 16 cm and 11 pieces of 8 × 20 cm. The median number of days with a drain was 12, (range 4-19 days). The total number of unsuccessful reconstructions was 10/76 (13%) (Table 2).

The main reasons for complications were skin necrosis (Figure 1) or fat necrosis followed by wound dehiscense and infection. These three factors have a significant impact on the outcome of reconstruction (Table 3).

Smoking, hypertension and age seem to have an impact on the outcome of intended breast reconstruction. Only two intended reconstructions failed in non-smokers (4%) compared with eight failures in patients who smoked (33%) (Table 2). This is statistically significant, p = 0.001 (χ2-test). Interestingly, out of the two non-smokers in whom an intended reconstruction failed, one was hypertensive and the other was a former smoker. In hypertensive patients, six out of 12 intended reconstructions failed (50%) (Table 2), compared with only 4/64 intended reconstructions in normotensive patients (6%), p = 0.001. The impact of hypertension may be confounded by the fact that five out of the six failed reconstructions were also smokers. The median age in the group of patients with a successful outcome was 50 ± 10 years compared with 63 ± 9 years in those who failed (Table 2). The median age overall was 51 years. However, the age distribution was skewed; 7/10 patients in whom the reconstruction failed were older than 66 years of age. None of the other factors measured, including diabetes and adjuvant therapy, showed any significant impact on the reconstructive outcome.

DISCUSSION

In our series of 59 women, we achieved 66 successful reconstructions out of the 76 intended using an ADM and an implant (87%), Table 2. The success rate in non-smokers was 52/54 (96%), which is comparable to the results presented in other papers [9]. We chose to use ADM for breast reconstructions in all patients disregarding any proposed exclusion criteria or previously suggested risk factors to investigate if ADM had any impact on the risk of failure [10]. The Norwegian and Danish patient groups differed in the higher amount of smokers amongst the Danish population and greater number of bilateral cases and NSMs performed on the Norwegian population. Otherwise the groups were homogenous.

When the mastectomy flap was thin or felt compromised, we used an expander or a Becker type prosthesis with over 80% filling volume of saline in order to be able to compensate for skin flap tension if necessary or if the patient wished to have a bigger breast size post-operatively.

Hypertensive patients had a significantly higher risk of failure than normotensive patients. However, all but one of the failed breast reconstructions in the hypertensive group were smokers, Table 2. Age was another important factor, and the risk of failure appears to be higher in patients aged 65 years or older.

This is in accordance with published data on the impact of age on the risk of reconstructive failure [11]. The higher risk of failure among elderly patients in this series may represent the added years of tobacco smoking and thus the accumulated effect of smoking rather than age being a significant factor itself.

Seroma formation has not been a problem in our series, Table 3, in contrast to other published papers where seroma occurrence has been on average 6.5%, ranging from 0 to 15.4% [12, 13]. Our strict drain removal criterion in which drains were left until drainage was below 10-20 ml per day is a possible explanation for having only one case of prolonged seroma formation. Most published papers describe the use of Alloderm and not Strattice. However, Strattice has been shown to cause less seroma formation than Alloderm in comparative studies [13]. We had two cases of implant removal due to infection without skin flap necrosis, which is less than expected compared with previously published results [14]; however, a recent paper on surgical site infection risk factors is in concordance with our findings [15].

Chemo- or radiation therapy did not contribute to increase complication or failure rates in this series as found by others [16]. It must be stated that suboptimal aesthetic results or the need for corrective procedures were not considered complications and have not been addressed in this study.

There is a considerable amount of confusing and confounding evidence in the literature in terms of the use of ADM, and most of the studies are based on the human-derived Alloderm.

Based on our experience using ADM for immediate breast reconstruction, we find that non-smokers and normotensive patients can be reconstructed in one stage using an ADM and a permanent implant with a 96% success rate. Caution is advised if an immediate breast reconstruction is considered in active smokers even if they cease smoking, as well as in hypertensive patients. The combined use of an ADM and an implant seems to be a promising technique for immediate breast reconstruction. However, careful patient selection is warranted. Smoking, hypertension and age are important factors which add significantly to the risk of reconstructive failure. Despite a relatively small sample size, the significant results cannot be overlooked. Immediate alloplastic breast reconstruction using an ADM can be recommended to healthy non-smoking patients.

Correspondence: Jørn Bo Thomsen, Plastikkirurgisk Afdeling Z, Vejle Sygehus, Kabbeltoft 25, 7100 Vejle, Denmark. E-mail: jbth@dadlnet.dk.

Accepted: 15 October 2013

Conflicts of interest:Disclosure forms provided by the authors are available with the full text of this article at www.danmedj.dk