CHAPTER 4 Expanders and Breast Reconstruction with Gel and Saline Implants
Key Points
Introduction
Clinical use of tissue expansion dates back to 1957 where expanded postauricular skin was used to reconstruct a traumatic ear defect.1 Subsequent interest in this technique, and specifically its application to breast reconstruction, did not flourish until 20 years later when Radovan and Austad developed silicone tissue expanders, independently presenting their results in 19782 and 1979.3 Radovan described a saline-filled implantable silicone expander utilizing a port; Austad described a self-inflating tissue expander4 including a description of the histological features of expanded tissue.5,6 As the safety and efficacy of submuscular tissue expansion has improved, implant-based breast reconstruction has become one of the most frequently employed reconstructive techniques in eligible patients. Today, an understanding of implant reconstruction results through careful planning of tissue expander placement and judicious modification of the pocket at the time of permanent implant exchange is resulting in a more realistic appearance to the reconstructed breast, while technologic advances in implant design and biologic substitutes are providing improved soft tissue coverage, contour and a more realistic feel to implant-based breast reconstruction.
Indications and Patient Selection
The ideal candidate for implant-based reconstruction is the patient with durable, non-redundant soft tissue coverage desiring a moderate sized non-ptotic breast (Fig. 4.1). This allows for flexibility in final size, tends to create a more stylized contour of the breast, and is particularly well suited to bilateral reconstruction. In unilateral reconstruction the patient must be willing to entertain the possibility of contralateral breast augmentation, reduction, or mastopexy. These considerations hold true for immediate or delayed reconstruction patients. However, the delayed reconstruction patient who has received postmastectomy radiation therapy should be approached very cautiously as the complication rate in this setting may be exceedingly high7 (Fig. 4.2). Also, large-breasted patients who wish to maintain a large size in their reconstruction may not be able to achieve this with tissue expansion and implants. Tissue expansion may altogether be avoided in carefully selected patients who have received a skin-sparing mastectomy (e.g., prophylactic mastectomy) with unequivocally viable skin flaps. However, in those patients with significant soft tissue loss at the time of tumor extirpation, tissue expansion is usually necessary.
Radiation Therapy and Implant-Based Reconstruction
Radiation therapy may be administered before mastectomy in the instance of prior breast conservation therapy, immediately following mastectomy but before reconstruction, coincident with tissue expansion, or after completion of tissue expansion. Radiation therapy has traditionally been avoided in patients with T0, T1 or T2 tumors after mastectomy, based on the patient’s choice, rather than lumpectomy with radiation as defined in the NSABP-B-06 trial.8 However, an increasing number of patients desiring breast reconstruction are eligible for radiotherapy due to the increasing prevalence of breast cancer and expanding indications for adjuvant therapy.9 In 1999 the indications for radiation therapy for breast cancer after mastectomy were expanded to include patients with stage II disease having either a primary tumor diameter greater than 5 cm (T3) and/or four or more involved lymph nodes (Table 4.1).10 Currently the efficacy of radiation therapy in patients with one to three affected lymph nodes is in phase III trials (NSABP-B-39).11
As such, an understanding of the effects of radiation therapy on the reconstructive surgeon’s strategy has become increasingly important. Radiation therapy by itself is no absolute contraindication to implant-based reconstruction, but its limitations must be realized, and some surgeons may wish to avoid attempting to expand skin with anticipated irradiation. While the need for radiation may be determined prior to mastectomy in a subset of patients, an increasing number are offered postoperative radiation therapy following analysis of the permanent pathology of lymph nodes or tumor margins. Delayed primary reconstruction, in which the tissue expander is placed 3 or 4 days after mastectomy, may be performed to ensure negative pathology and no indication for radiation. In those patients where radiation therapy is indicated based on intraoperative findings such as tumor size, narrow margins or sentinel lymph node status, the reconstructive surgeon should reserve the option to ‘walk away’ from an immediate reconstruction. Some authors have suggested the use of a delayed-immediate reconstruction technique, where a partially inflated expander is placed immediately with interval deflation for the duration of radiation therapy, if indicated.12 In this circumstance of postoperative radiation, we prefer to expedite the expansion process to completion within 4 to 5 weeks, before radiation therapy is started.
In most centers, radiation oncologists do not perceive the tissue expander as a hazard to good treatment. If oncologic considerations require radiation prior to that time, delayed reconstruction is preferred. Those patients who have received even appropriately titrated radiation therapy are at greater risk for mastectomy flap necrosis, implant exposure or inability to complete tissue expansion (Fig. 4.3). However, a successful result can nonetheless be obtained (Fig. 4.4). As such, we often allow patients to ‘prove’ the expander will not work before resorting to autologous forms of reconstruction. Ultimately, autologous tissue coverage may be required to achieve an acceptable contour. Spear reviewed a series of saline implant-reconstructed women receiving radiation therapy at various time points relative to reconstruction and found autologous tissue was needed in 19 out of 40 (47.5%) patients primarily as a consequence of contracture or unsatisfactory implant position.13 These secondary operations still make use of the expanded tissue, and may be thought of as an adjunct to implant-based reconstruction, rather than salvage for a failed operation. No additional operations are required than if the patient had proceeded to autologous tissue transfer, initially or at a later date; the only disadvantage is the time and inconvenience for the patient having undergone an expansion process that does not progress to completion or ultimately fails. In those secondary or delayed reconstruction patients who have received very high doses of radiotherapy, we do not attempt tissue expansion alone, and proceed directly to autologous tissue transfer with or without the use of an implant and expander.
Preoperative Marking and Tissue Expander Selection
Preoperative coordination with the surgical oncologist is critical for obtaining a favorably placed mastectomy scar that can be concealed by clothing with preservation of as much skin envelope as needed. The importance of preserving the inframammary fold should be appreciated by the oncologic surgeon. With greater acceptance of skin-sparing and areola-sparing mastectomies, incisions other than a standard periareolar ellipse may affect surgical exposure (Fig. 4.5). In the large-breasted patient who wants significantly smaller breasts and has no indication for radiation, a mastectomy scar incorporating a vertical component, or based on an inverted ‘T’ incision as seen in Wise pattern breast reductions, may be considered (see Fig. 4.27).
With the final result in mind, tissue expanders of appropriate dimensions are ordered prior to the surgery. A range of tissue expanders are currently available, including round and contoured expanders, the latter offering the benefit of differential, greater lower pole expansion, and an increasing slope from the upper pole. Most expanders utilize an integrated valve that is located using a magnetic port finder (Fig. 4.6). If expander positioning is ideal, a remote port expandable implant provides an option of explanting only the port and interconnecting catheter, leaving the implant in place as a permanent device. Each tissue expander has a specific base diameter, height, contour profile (e.g., low, moderate, and tall), and maximum recommended volume (Fig. 4.7). We use base diameter as the primary determinant of implant choice with volume as the second consideration. The choice of profile is largely based on the habitus of the patient, with narrow-chested, thinner patients appearing proportional with low or medium profile expanders and heavier patients requiring a tall profile to offer projection commensurate with their larger size.
Operative Technique: Immediate Reconstruction
Patient positioning
Pocket dissection
With the deficiency of soft tissue coverage resulting from the mastectomy, partial or complete muscle coverage is necessary to limit implant visibility or exposure. We prefer complete muscular coverage of the expander to maximize the vascularity of the pocket and exclude the implant from the overlying mastectomy incision. In this technique, the lateral edge of the pectoralis major muscle is elevated and a submuscular pocket is dissected medially to the sternal edge and superiorly to the second rib. The superior dissection is made in a relatively avascular plane between the pectoralis major and minor muscles. Care should be taken to avoid injury to the thoracoacromial pedicle located on the undersurface of the pectoralis major muscle. A systemic paralytic may be administered to make the superior dissection easier, as powerful contractions of the pectoralis major may result from electrocautery dissection near its dominant neurovascular pedicle. Superior dissection may be made bluntly, and while technically easy, excess dissection in this direction may lead to implant malposition, as the expander is wider than it is tall. When possible, the large perforator in the medial second interspace is preserved because of its contribution to the mastectomy flap blood supply (Figs 4.8 and 4.9A–C).
