Early implant-based reconstructions involved the placement of implants directly under the mastectomy flap in a «subcutaneous» position. This technique fell out of favour as it was found to be associated with a high degree of complications, as well as unsatisfactory cosmesis. Consequently, techniques were developed in which chest wall musculature was used to provide coverage of the implant, with the aim of reducing implant exposure, palpability and visible rippling by providing an additional soft tissue layer between the incision and the implant. Sub-muscular implant coverage may be «total» (in which sub-pectoral and sub-serratus muscular pockets are created and joined together to provide complete implant coverage) or «partial» (where just a sub-pectoral pocket is created and the lower pole of the implant therefore lies subcutaneously).

Both total and partial sub-muscular techniques are associated with limitations. Firstly since the size of the implant pocket that can be created with either approach is constrained by available skin and muscle, immediate reconstruction generally requires a two-stage (tissue expander/implant) approach unless the patient is very small breasted. With the partial sub-muscular technique, only the superior part of the implant is covered by muscle, which leaves the lower pole of the implant vulnerable to exposure, should skin necrosis or infection occur. In addition, if the flaps are initially thin, or atrophy with time, then the implant and any creases or wrinkles in its surface may be easily palpable. The released lower edge of the pectoralis muscle can also adhere to the skin, such that when it contracts, there is an unsightly deformity known as «window shading» that requires surgical correction. With total muscular coverage, elevation of the serratus anterior muscle can be associated with pain both at the time of surgery and during the expansion phase. Furthermore, tight banding of the raised muscle or fascia across the lower pole may result in difficulty in controlling expansion vectors resulting in flattening and unnatural breast shape. Both techniques can result in lack of control over the position of the IMF, in a flat unnatural look, and make it difficult to achieve a natural looking ptosis.

The «lower pole sling» technique has been developed to avoid the problems associated with partial or total sub-muscular implant placement described above. This technique uses a piece of mesh which is sutured superiorly to the lower border of pectoralis major and inferiorly to the inframammary fold, such that it augments the volume of the implant pocket, lowers the IMF and reduces muscular dissection [12]. Although many different meshes, both biological and synthetic, are now available on the market for this purpose, there is more evidence on the use of «acellular dermal matrices» (ADMs) – as this technique was first described with ADM.

ADMs are sterile, acellular, biological pieces of material derived from human or animal tissue (usually skin), in which the dermis is stripped of cellular components leaving a structurally intact and biochemically inert, extracellular matrix [13]. Whilst the human skin-derived ADM, «Alloderm,» was the first ADM to be described in the literature [14], multiple ADMs have now entered the market derived from both allogenic and xenograft (porcine and bovine) donor sources. As well as dermally derived products, other tissues such as pericardium and peritoneum have also been used to create meshes with similar properties [15]. The first report of using an ADM in reconstructive breast surgery was by Breuing and Warren in 2005, with their series of ten patients who underwent bilateral mastectomy and direct-to-implant single-stage reconstruction using Alloderm [14]. The first series of ADM use in two-stage expander/implant surgery was described by Bindingnavale and colleagues in 2007 [16].

Proposed benefits of ADM use in implant-based reconstruction are described below:

The use of ADM to extend the sub-pectoral pocket allows one-stage breast reconstruction to be performed when there is sufficient preservation of the skin at the time of mastectomy. This eliminates the need for the tissue expansion phase. It is suggested that this simplifies the process of reconstruction, potentially reduces the time to completion of reconstruction and therefore minimises cost [17–19].

Reconstructions using ADMs may result in less pain by reducing the extent of muscle elevation to create the implant pocket, thereby reducing the degree of neuronal disruption compared to a standard sub-muscular technique. However the evidence that post-operative pain is reduced by ADM use is purely anecdotal at present. McCarthy and colleagues randomised patients undergoing mastectomy from two US hospitals into cohorts who received two-stage immediate breast reconstruction either with or without ADM and was unable to demonstrate a significant difference in pain scores between the two cohorts either post-operatively or during the expansion phase [20].

As a larger pocket may be developed when an ADM is used, it is proposed that this may allow increased initial fill volumes and faster expansions in two-stage procedures. There is conflicting data in the literature with comparative retrospective cohort studies both supporting and refuting this [21]. Factors which may account for this discrepancy include patient factors (the ability of different patients to tolerate varying fill volumes, patient availability and the patient’s physical characteristics) and surgeon preferences for the frequency and volumes of expansions.

The rationale behind this theory is that by securing the ADM to the lateral and inferior borders of the breast pocket, this defines the inframammary fold and enables reliable placement of the implant whether placed as one stage or at the time of exchange. Additionally, the alternative technique using complete sub-muscular coverage of tissue expanders restricts the ability of the lower pole to fully expand, whilst placement of an ADM would allow less constriction. This therefore enables full use of the mastectomy flap to allow a natural curve of the lower pole. There are a few studies which report ADM-based reconstructions as having a better cosmetic outcome compared to standard sub-muscular implant placement based on panel assessment of cosmesis from post-operative photographs [22, 23], but follow-up is relatively short.

Initial experimental evidence which showed reduced inflammatory reactions associated with ADM use in both animal models and human capsule specimens has been backed up by some clinical studies but has not as yet been evaluated in a prospective trial. Studies with long-term follow-up of ADM-assisted reconstructions have, however, demonstrated a low cumulative rate of capsular contracture even in the setting of radiotherapy [17, 24]. However there are no randomised comparisons, and the rate of capsule formation is still higher in ADM cases when radiotherapy is used so it clearly does not abolish the problem completely [92].

The use of a dermal sling in implant-based reconstruction was first described in 1980 by Tanski [30] and further refined by Hammond and colleagues [31], Bostwick [32] and Nava and colleagues [33]. This technique uses a similar principle to the lower pole support offered by ADMs but uses instead the de-epithelialised excessive skin of the lower pole of the breast to provide an entirely autologous, well-vascularised tissue coverage for the lower pole of the implant. This technique is generally offered to women with large ptotic breasts who can be offered a skin-sparing mastectomy, as it makes use of the redundant skin normally excised as part of the skin-reducing Wise pattern incision. Since a skin-reducing incision pattern is used, patients should be counselled that a contralateral mastopexy/reduction is usually required for symmetrisation.

There are only a limited number of case series in the literature reporting on outcomes of the dermal sling technique [34–37]. Whilst earlier case series report high incidences of skin necrosis and implant extrusion, the more recent ones report equivalent outcomes to the use of an ADM [37]. In particular, T-junction dehiscence, which commonly occurs with the Wise pattern incision, is well tolerated due to the underlying dermal sling which prevents implant exposure. Safety and efficacy in the presence of radiotherapy have not been studied to date.

Pre-pectoral implant placement is commonly used for cosmetic breast augmentation but until recently has not generally been used following skin-sparing mastectomy due to unacceptable complication rates, poor cosmetic outcomes and high rates of capsular contracture in early series [93]. With the introduction of biological and synthetic meshes, which provide a replacement for soft tissue coverage, there has been a recent resurgence in this technique. This is based on the rationale that both ADMs and synthetic meshes can be safely placed subcutaneously between the implant and mastectomy flaps when providing support for the inferior pole in retro-pectoral reconstructions described above. There are suggestions that pre-pectoral placement, as well as simplifying the reconstruction overall, may improve patient outcomes by avoiding some of the issues associated with the use of retro-pectoral implant placement such as functional impairment of the pectoralis muscle, breast animation associated with muscle contraction and post-operative pain associated with detachment of pectoralis major as well as during the expander phase in two-stage breast reconstruction. Furthermore by recreating the natural anatomical position of the breast in front of the pectoralis muscle, it is suggested that a more natural appearance may result. Whilst patient selection is generally limited to those with decent subcutaneous tissue coverage, the concomitant use of lipomodelling to improve the quality of the subcutaneous tissue layer may mean this technique becomes available to a larger proportion of women. The technique has several variations, but the general principle involves wrapping either a fixed volume or expander implant within a mesh pocket [38–41]. This pocket may be an acellular dermal matrix or any of the alternatives described above and is either constructed by the surgeon or available in a preformed shape (◘ Fig. 30.5). In the case of expanders, the mesh should be wrapped loosely to allow for an increase in volume. The covered implant is then fixed in position to the underlying chest wall using anchoring sutures between the mesh and the underlying pectoralis muscle. Drains are then placed and skin flaps closed directly over this.

Although initial outcome data is promising, it is currently too limited at present to make a definitive conclusion as to whether pre-pectoral implant placement offers benefits over the retro-pectoral lower pole sling technique (◘ Table 30.2 presents an overview of studies of pre-pectoral implant placement).