42.1 Introduction

In 2016, over 245,000 women were diagnosed with breast cancer in the United States. Of these, just over 109,000 women underwent mastectomy with reconstruction; 86,000 of them were treated with prosthetic-based reconstruction, 90% of which were two-stage expander–implant procedures with 10% being direct-to-implant (DTI) approaches. With respect to implant positioned, 83% where subpectoral while 17% were prepectoral.

Implant-based reconstruction has undergone significant changes in the last decade. Three technological advances have ushered in a new era in breast reconstruction:

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  Improvements in implant design.

  
  
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  Availability of skin perfusion techniques.

  
  
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  Acellular dermal matrices (ADMs).

In addition, there has been the recent focus once more on the prepectoral plane for breast reconstruction.

42.2 The Original Rationale for Subpectoral Breast Reconstruction

When the first Cronin–Gerow gel-filled implants were introduced in 1962, these were used for breast augmentation in the subglandular plane. Subsequently, these were used for breast reconstruction following subcutaneous mastectomy for chronic pain associated with fibrocystic disease. It soon became apparent, however, that complications where significant, including capsular contracture, rippling, severe asymmetry with malposition, deformity, and chronic breast pain.

At that time, the Halsted radical mastectomy had reigned supreme in breast cancer management and it was only as the procedure was altered as modified radical mastectomy to preserve more muscle that alternative techniques of breast reconstruction became feasible.

In breast augmentation, the implant pocket was moved into the subpectoral plane in order to ameliorate the complications of the subglandular approach. This change was ported into the reconstructive arena and subpectoral reconstruction became the gold standard for breast reconstruction.

The move to the subpectoral plane was motivated by several perceived potential benefits.

While capsular contracture rates did appear to drop slightly and implant visibility problems were softened, the subpectoral position introduced a new set of complications to breast reconstructive surgeons.

The introduction of total submuscular coverage followed on as a natural progression; if partial muscle coverage was superior to subcutaneous cover, then total muscle coverage must be better! The concept involved raising pectoralis major, the anterior border of serratus anterior as well as the superior origin of the rectus abdominis muscle and its associated fascia in an effort to create a complete submusculofascial envelope to cover the implant. The major benefit to this approach was that if skin necrosis of the inferior flap supervened following mastectomy, muscle present at the base of the wound allowed for granulation and delayed healing to occur. This was a positive development at a time when perfusion assessment was limited to fluorescein injection at best.

The problem with this approach was the intense tightness of the confluence of pectoralis major, serratus anterior, and rectus abdominis creating a point of maximal pressure at exactly the area where the surgeon needed elasticity for lower pole projection (▶Fig. 42.1). The result was loss of lower pole projection, forcing displacement of the reconstruction in a cephalad direction with bulging of the implant below the clavicle (▶Fig. 42.2).

Given the negatives of total submuscular coverage, many surgeons sought to move away from this approach into a dual-plane technique incorporating pectoralis major above and the lower pole breast skin below. This left a significant amount of the implant covered only by skin, exacerbated by the problem of window-shading deformity occurring when the lower portion of the pectoralis major was released from its origin to accommodate the expander–implant volume.

42.3 Acellular Dermal Matrices

Spear offered the first solution to window-shading deformity by suggesting the use of marionette sutures between the pectoralis major and the overlying mastectomy skin envelope (▶Fig. 42.3). While this helped to alleviate the problem to some extent, it was also capable of inducing ischemic changes in the mastectomy skin envelope. A more permanent solution became apparent when ADMs were introduced. These products were sutured from the caudal border of the pectoralis major over the lower pole of the implants to the chest wall creating an anchor between the pectoralis major and the inframammary crease, thereby minimizing window shading. The ADM also acted as an internal bra to hold the implant in place and enable control of the subpectoral pocket to a degree never before achieved (▶Fig. 42.4). Given our more recent understanding of biofilms and their role in capsular contracture, as well as the fact that ADM modifies capsular biology to reduce capsular contracture development, this troublesome complication has been dramatically reduced.

42.4 Implant Shape

The use of more cohesive gel implants aided in reducing rippling and improving shape. Shaped anatomical implants have almost eliminated the upper pole hollowing seen so commonly with round devices and have, as a consequence, caused a reduction in the need for upper pole fat grafting (▶Fig. 42.5).

42.5 Perfusion Assessment Devices

Wound healing complications and skin necrosis after breast reduction occur in between 6 and 45% of patients depending on the series reported. Reduction in wound healing complications and skin necrosis has been achieved most successfully through the use of perfusion assessment devices. While fluorescein perfusion enabled flap assessment to some degree, it tends to overread potential necrosis resulting in unnecessarily large amounts of skin being resected. Laser-induced fluorescence of indocyanine green (ICG) dye provided a much more accurate, real-time assessment of skin perfusion that could be repeated multiple times during a given procedure. Floor-mounted and handheld devices are available at varying costs, but they still remain very expensive. New technologies including thermography (FLIR device) and various forms of spectral imaging are coming onto the market and it will be interesting to watch the development of this niche technology subset.

When teaching this procedure to surgeons, it has often been my experience that they mention the thickness of skin flaps as a limiting factor in being able to perform the procedure.

I have performed this procedure in dozens of patients with extremely thin skin flaps who have had highly successful outcomes. This has been based not on their skin flap thickness but on their skin viability. Skin perfusion assessment devices have been invaluable in providing this level of safety during the procedure.

Given the development of these three different technologies, the stage was set for the successful launch of a prepectoral approach to breast reconstruction for the first time since the 1960s. While technologically feasible at this point, many surgeons ask the question “Why change to the prepectoral location when subpectoral reconstruction has provided reasonable success?” The answer to that question lies in the way in which we define success in the past. If success is defined as creating a reasonably soft round mound on the chest wall, yes it has been achieved. The problem is we have always tended to examine our patients with their arms at their sides and tend not to ask penetrating questions about aesthetics, cleavage, function, and the daily struggles with tightness and animation. If we factor into the assessment natural shape as well as the behavior of the breast during arm motility and activities of daily living, we suddenly find our supposedly successful reconstructions failing miserably. Patients find animation deformity to be embarrassing and the tightness of subpectoral implant placement to cause chronic discomfort during activity and at rest.

42.6 The Impact of The Pectoralis Major Muscle on Animation Deformity

This can be defined as adhesion between the pectoralis major and the overlying mastectomy skin flap resulting in bizarre and often uncomfortable contraction of the skin envelope during upper extremity emotion. The only reasonable cure for the problem is to separate the muscle completely from the skin with a relatively inanimate object in the form of a breast implant or flap reconstruction.

42.7 The Impact of the Pectoral Muscle on Cleavage Formation

One of the difficulties of placing breast implants in patients, whether for reconstruction or for cosmetic augmentation, has been the creation of attractive cleavage. Many implant-based procedures are marred by the presence of a wide, flat expanse between the two breasts even when the latter have reasonable shape and volume. This absence of cleavage is an important factor in the aesthetic outcome of any breast procedure whether cosmetic or reconstructive and for many women it is one of the crucial elements in their assessment of success.

The location of the medial pectoral origin varies tremendously between different women. In some patients the medial borders almost approximate each other on the anterior aspect of the sternum, while in other women the muscles can arise as far lateral as the costal cartilages and even rib surfaces. When performing either subpectoral breast augmentation or breast reconstruction, the inferomedial origin of pectoralis major is divided to allow easier accommodation of the implants beneath the muscle. Despite this release, the remaining superomedial attachment of the pectoralis major acts as a physical barrier to medial implant placement. No amount of increasing implant volume can impact this physical limitation in a positive way. The wider the spacing of the pectoral origins, the wider, and less well-defined will be the ultimate cleavage created.

This is clearly demonstrated in ▶Fig. 42.6.

These aesthetic and functional considerations prompted the author to move toward performing only prepectoral breast reconstruction. With the accuracy of skin perfusion assessment, the better shapes of our implants coupled with the use of ADM, I can no longer justify performing subpectoral reconstruction and find expanders necessary in only the most extreme situations or for delayed reconstruction.

Related posts:

49 Preventing and Managing Complications in Latissimus Dorsi Flap Reconstruction 45 Preventing and Managing Complications of Expander–Implant Reconstruction 47 Latissimus Dorsi Flap Anatomy 44 Two-Stage Prepectoral Prosthetic Breast Reconstruction 39 Prepectoral Breast Reconstruction: Direct-to-Implant versus Two-Stage 51 Transverse Rectus Abdominis Musculocutaneous Flaps

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