Subcutaneous Reconstruction Without Acellular Dermal Matrix

Fig. 15.1

Preoperative radiation therapy . (Left) Fifty-seven-year-old patient who had been previously treated with left partial mastectomy and radiation therapy. The patient underwent bilateral nipple-sparing mastectomy and staged subcutaneous reconstruction with 400 ml silicone implants. (Right) Result at 21 months

Rapid expansion for improving breast shape with acellular dermal matrix is considered advantageous when partial muscle coverage is compared with total muscle coverage that blunts the lower half of the breast [11, 12]. Subcutaneous expansion is as fast, if not faster than submuscular expansion with a cellular dermal matrix, because the muscle does not require expansion and the lower portion of the breast readily assumes the full rounded shape of the underling expander with very little expansion. This leaves the upper half of the breast that does not require expansion ready for augmentation with a final implant that is twice the size of the expander fill volume (Fig. 15.2). Also, in subcutaneous reconstruction the pectoralis muscle does not need to be detached from the sternum to improve the cleavage nor does the muscle have be expanded in its upper portion or the tail of the breast region, as these areas can be readily augmented with subcutaneous implantation (Fig. 15.3). The major drawback of submuscular reconstruction is the difficulty in expanding the infraclavicular portion of the muscle that often leaves a step-off contour deformity along the upper border of the implant requiring fat injection [13].

Fig. 15.2

Moderate inflation of tissue expander . (Above, left) Thirty-eight–year-old patient with left breast carcinoma who underwent bilateral nipple-sparing mastectomy. (Above, right) Expanders inflated up to 240 ml. The final implant will cover a larger area requiring a larger implant to fill the upper and medial portions of the breast (Blue broken line). (Below) Reconstruction with 550 ml silicone gel implants at 16 months

Fig. 15.3

Suprapectoral reconstruction . (Left) Fort-nine-year-old patient with left invasive ductal carcinoma who underwent bilateral nipple-sparing mastectomy and staged suprapectoral reconstruction. (Right) Result of reconstruction with 525 ml silicone gel implants at 4 years

Subcutaneous expansion is reliable in defining the inframammary fold if thick mastectomy flaps are used and the fold ligaments [14] are not disrupted during the mastectomy and second-stage reconstruction. In thin individuals (BMI = 21) with relatively large implants, it is preferable to anchor the chest skin at the inframammary fold to the rib periosteum with nonabsorbable sutures during the second-stage reconstruction to avoid implant migration. Finally, subcutaneous reconstruction without acellular dermal matrix carries less morbidity and is more cost-effective.

Capsular Contracture in Staged Subcutaneous Breast Reconstruction

One of the reasons for the acceptance of submuscular breast reconstruction with acellular dermal matrix, rather than the supramuscular method, is the reduced rate of capsular contracture [15]. Clinical evaluation, corroborated with laboratory studies, has shown decreased inflammatory response to acellular dermal matrix that results in a thinner capsule and less capsular contracture [16, 17]. In spite of its disadvantages in staged suprapectoral breast reconstruction, capsular contracture has certain advantages in the ptotic breast that cannot be overlooked. If the expander is placed subcutaneously and expanded minimally, capsule formation may be desirable to reduce the skin surface area and “lift” the breast to improve the ptosis. Most patients with medium or large breasts and Regnault grade II/III ptosis benefit from the “lift” provided by capsular contracture.

Capsular contracture rates are time dependent with Baker grade III/IV capsular contractures typically developing several years after the completion of reconstruction. Our average 33.5-month follow-up breast capsular contracture rate for Baker grade III/IV contractures was 3 % [4]. This capsular contracture incidence will probably increase with longer follow-up periods. The overall advantages and disadvantages of capsular contracture should be considered in making a decision whether to place the implant subpectorally or subcutaneously.

Complications

Major complications in subcutaneous reconstruction such as postoperative bleeding, infection, expander exposure, and explantation are comparable to submuscular reconstruction. In subcutaneous reconstruction skin loss can be avoided if the breast flaps are kept thick and subcutaneous fat thinning around the nipple-areola, as previously mentioned, is limited to 16–25 cm². Major skin loss following subcutaneous mastectomy or extensive radiation damage is treated with latissimus dorsi myocutaneous flap transfer. For minor skin loss, the eschar is excised in the operating room and the wound closed primarily leaving the expander in place to complete the reconstruction in two stages. Patients who develop a deep wound infection following the mastectomy will require removal of the expander to allow the wound to heal for several months before reconstructing the breast with a permanent implant. Direct subcutaneous permanent implantation is feasible because the skin does not require expansion, other than a radical capsulotomy, to restore its original surface area.

Other relatively minor complications in subcutaneous reconstruction include implant dystopia and rippling. With thick mastectomy flaps implant dystopia and rippling is uncommon. We have seen implant migration in thin women (BMI = 21) with implants larger than 400 ml. This deformity can be corrected with fixation of the chest skin along the inframammary fold to the rib periosteum with nonabsorbable sutures. To avoid this complication, we routinely tack the skin down to the rib during the second-stage implant exchange in thin women who desire large implants. Rippling in thick mastectomy flaps is minor and is treated with implant exchange or low volume lipofilling.

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