Implant-based breast reconstruction is the most frequently performed reconstructive technique following breast ablative surgery.1 For the past 15 years, this technique has been performed primarily with subpectoral implant placement by means of the dual-plane approach. The coverage and support provided by the pectoralis major muscle has not only minimized implant-related complications but also mitigated the risk of capsular contracture and produced a more natural-appearing breast.2 However, a concern with this approach is the risk of animation deformity and associated breast discomfort,3 which is a direct consequence of muscle elevation. Changing the implant site to prepectoral may provide some relief, and predictable results can be obtained with prepectoral placement (and the dual-plane approach) with application of the bioengineered breast concept. This concept involves the use of a combination of form-stable and/or higher-fill implants, regenerative acellular dermal matrices, and fat grafting.4 We have previously reported on the original bioengineered group of dual-plane reconstruction patients,4 and in this report, we review the background and rationale for prepectoral placement using the bioengineered concept, propose indications/contraindications for its use, and present our preliminary results from over 350 reconstructions.
HISTORY OF SUBPECTORAL PLACEMENT
Silicone breast implants, introduced in the early 1960s, marked the beginning of the modern era of implant-based breast reconstruction. The first breast reconstructions using silicone implants involved placement of the implant in a subcutaneous pocket, beneath the mastectomy skin but over the pectoralis major muscle. This subcutaneous approach was simple and quick and preserved the integrity of the pectoralis muscle but was associated with a number of complications. Implant malposition (bottoming out), visibility, and palpability; rippling/wrinkling; implant exposure subsequent to skin breakdown; and capsular contracture were some of the most commonly reported complications.5 With the realization that these complications arose from insufficient soft-tissue coverage, breast reconstruction technique evolved to moving the implant from the subcutaneous to the submuscular position.
In submuscular placement, the implant is placed under the pectoralis major muscle without releasing the inferior origin of the muscle. Full muscle coverage of the implant is achieved by recruitment of muscle flaps (serratus anterior and rectus abdominis sheath) for lateral and inferior coverage of the implant. Full-muscle coverage eliminated the soft-tissue coverage limitations of the subcutaneous approach but resulted in unnatural-appearing breasts. The inferior restrictions imposed by the submuscular pocket prevents lower pole expansion that results in poor breast projection, ptosis, and poor definition of the breast shape.5 In addition, recruitment of muscle flaps introduced donor-site morbidity.
To address the inferior restriction of full muscle coverage, the partial muscle coverage or dual-plane technique was introduced. In partial muscle coverage, the implant is covered partially superiorly by the pectoralis major and partially inferiorly by only the mastectomy flap.6–8 The inferior subcutaneous coverage allows for lower pole expansion and eliminates the need for flap recruitment for lower pole coverage. Partial muscle coverage, however, introduced a new problem. Without its inferior attachment, the pectoralis major is free to migrate superiorly, resulting in “window-shading.” Moreover, subcutaneous coverage at the lower pole reintroduced the problems seen with subcutaneous implant placement.
To address the problem of lower pole coverage, acellular dermal matrix was introduced in breast reconstruction in 2006. In this widely used modification of the partial muscle coverage technique, acellular dermal matrix sutured at the lower pole provides the additional support needed at the inferior pole.9–12 With lower pole acellular dermal matrix placement, complications associated with subcutaneous coverage are minimized without restricting lower pole expansion.9,12,13 Although this technique resolves some of the concerns of partial muscle coverage (without acellular dermal matrix), the pectoralis major muscle remains elevated and window-shading remains a problem. Window-shading can, however, be minimized by stabilizing the muscle and altering the degree of release of the muscle origins.
RATIONALE FOR PREPECTORAL PLACEMENT
Subpectoral prosthesis placement with partial muscle coverage, with or without acellular dermal matrix, is currently the standard technique for implant-based breast reconstruction. Many of the disadvantages/complications of subcutaneous implant placement (e.g., implant visibility, palpability, and exposure and capsular contracture) are mitigated with the subpectoral technique because of the thicker coverage provided by the muscle. Elevation of the muscle, however, has introduced its own set of problems, including animation deformities caused by muscle contraction, chest tightness, pain, and muscle spasm.3 Furthermore, subpectoral placement creates an unnatural state, as the natural breast is anterior to the muscle. Despite these concerns, patients who have had dual-plane reconstruction with acellular dermal matrix can have aesthetically pleasing results14; however, with any contraction of the pectoralis major, animation deformity on the chest can be noted immediately. We have used fat grafting as a means to establish a natural gliding surface between the thin mastectomy flap and the pectoralis/acellular dermal matrix interface, which decreases the pain and the visual deformities associated with the scarred mastectomy flap being pulled by the pectoralis major.4 This ameliorates but does not eliminate animation deformity, and some degree of animation remains.
As a further means of alleviating muscle-related issues, we resorted to moving the implant from the subpectoral back to the prepectoral (subcutaneous) position in certain revision cases. We then used our bioengineered breast concept to overcome the limitations of subcutaneous placement and improve the aesthetic outcome.4 The bioengineered breast concept, described in a prior publication,4 involves the use of autologous fat cells, scaffolds (acellular dermal matrices), and cohesive gel implants to recreate the breast. Bioengineered breast is not a technique but rather a principle of replacing the missing tissues after ablative surgery to recreate a breast that appears and feels like the natural breast. In prepectoral reconstruction, using form-stable and/or higher-fill implants, we reinforced the entire breast pocket with acellular dermal matrix to mimic muscle coverage and performed fat grafting to enhance the thickness and the gliding ability of the subcutaneous pocket. Prepectoral revision reconstruction has produced consistent outcomes, with resolution of animation deformity and implant-related complications in appropriately selected patients.
We have been using the prepectoral approach in our revision cases since 2008 and have refined the technique further. Initially, we placed the acellular dermal matrix anteriorly over the implant, but given the complexity of placement of acellular dermal matrix and its suturing, we attempted to find a more efficient solution to simplify acellular dermal matrix use. To this end, various off-label constructs of prosthesis and acellular dermal matrix were configured for placement into the prepectoral space. We continue to use both of these techniques for acellular dermal matrix placement in our practices.
The simplicity of the prepectoral concept and the good outcomes observed in our revision cases led us to adopt the concept into our primary reconstructions. Since June of 2008, we have performed prepectoral implant placements in selected primary reconstructions as a means of proactively addressing complications associated with subpectoral placement and to simplify the reconstructive process. The acellular dermal matrix is placed at the time of primary reconstruction with an implant or expander. Fat grafting is performed at the second and/or the third stage. Fat grafting is never performed at the time of expander or implant placement immediately after mastectomy. In expander-based reconstruction, fat grafting is performed during the second stage only if no additional capsulotomies are performed. Virgin tissue is required for fat grafting; in the absence of such tissue, loss of the graft and infection may occur around the implant. If capsulotomies are performed, fat grafting is performed as a third stage, as illustrated in Figure 1, at a minimum of 3 months but possibly as long as 1 year after the second stage, depending on patient preference.
To date, 353 prepectoral, implant-based, primary reconstructions (146 bilateral) in 207 patients, following skin- or nipple-sparing mastectomies, have been performed in our practices (Table 1). AlloDerm (LifeCell Corp., Branchburg, N.J.) was used in all reconstructions to support and reinforce the prepectoral space. Of the 207 patients, 18 were BRCA-positive, 23 underwent single-stage reconstruction (46 breasts), seven underwent delayed reconstruction (14 breasts), 17 underwent postsurgical radiotherapy, and 10 underwent preoperative radiotherapy. Patients were followed from 6 to 26 months after completion of single- or two-stage reconstruction.
Complications after reconstructive surgery included infection, seroma, and flap necrosis, each occurring at an incidence of less than 5 percent (Table 2). There was no incidence of capsular contracture. Patients with prior radiation therapy had a higher complication rate (five of 10). Given the small cohort size of these patients, no direct associations can be made between the impact of prior irradiation on outcomes. In our opinion, the irradiated pectoralis major muscle adds to the deformities and discomfort and has an adverse effect on long-term outcomes. In contrast, patients who underwent unplanned radiation therapy postoperatively in our cohort remain complication-free to this date. Whether prepectoral placement of implants provides a protective benefit against postoperative irradiation remains to be seen. The decision to irradiate implants or expanders in the prepectoral space is, however, dependent on the comfort level of the radiation oncologist.
INDICATIONS FOR PREPECTORAL PLACEMENT
Although the prepectoral approach presents an alternative muscle-sparing reconstructive approach, not all patients are candidates for this approach (Table 3). Critical to this approach is the availability of adequately vascularized skin flaps. Because of the proximity of the implant to the skin flap, any skin-related complications can potentially compromise the reconstruction (thus the absolute indication for adequate vascularization of these flaps). To ensure the integrity of skin flap perfusion, we recommend close collaboration with general surgeons to minimize aggressive mastectomies. In addition, we recommend objective assessment for tissue perfusion using devices available for this purpose before prepectoral reconstruction in every patient. As prior breast irradiation and active smoking can compromise skin perfusion, the prepectoral approach should be contraindicated in such patients at this time. Candidates should also have adequate fat depots for fat grafting, as it is integral to the prepectoral approach. Patients who are obese and immunocompromised are at increased risk of complications in general and are not suitable for this approach. Obese patients (body mass index >35 kg/m2) with no radiation therapy history can undergo delayed prepectoral reconstruction. These patients undergo a delayed first-stage reconstruction, which includes fat grafting under the mastectomy focusing on raising the central mastectomy scar in preparation for the second stage of prepectoral reconstruction. Elevation of the central scar helps in minimizing complications in a prepectoral placement, given the tendency for thin flaps around old scarred incisions.
Oncologic Guidelines and Indications
The oncologic guidelines for the prepectoral approach remain to be defined. As a multidisciplinary treatment plan is most optimal for the comprehensive care of the breast cancer patient, a combined effort is needed to balance the safest oncologic care with the most desirable aesthetic outcome. The oncologic treatment plan is frequently configured based on availability of resources and the willingness of each discipline to embrace and be able to safely adapt to changes brought about by new techniques.
Prepectoral reconstruction can be safely performed in patients undergoing skin-sparing mastectomy for breast cancer using the same oncologic parameters as would be applied for subpectoral implant-based reconstruction. As with subpectoral reconstruction, extreme caution should be exercised for large tumors, positive lymph nodes, and skin and chest wall involvement (Table 3), especially in centers where postmastectomy radiation therapy is not used. When performing nipple-sparing mastectomy, guidelines identical to those used for nipple-sparing mastectomy with subpectoral reconstruction should be followed.15 Because these guidelines are continuing to evolve, it is prudent to be cognizant of available randomized, prospective, clinical trial results. Furthermore, it is imperative to approach patient selection from a multidisciplinary standpoint, involving the surgical team (reconstructive and oncologic) and the medical team (oncologist, radiation oncologist) and most definitely radiation oncology in any case where adjuvant radiotherapy is anticipated.
In addition to these general guiding principles, we have identified a number of contraindications for prepectoral placement in oncologic patients. In particular, patients with late-stage breast cancer, posterior tumors lying near the pectoralis major muscle, and a high risk of recurrence are not candidates for prepectoral placement, as the oncologic safety of prepectoral placement is not yet known. Monitoring for cancer recurrence is thus recommended using a protocol similar to that undertaken in autologous reconstructions. Autologous flaps are routinely placed in a prepectoral location, and these flaps are regularly monitored for cancer recurrence by clinical examinations and at times by radiologic screening. Similarly, in prepectoral reconstruction with implants, clinical and monthly self-breast examinations are important, as breast cancer recurrence in the majority of the cases occurs under the mastectomy flap. We have instituted a follow-up protocol of our prepectoral reconstructions using the U.S. Food and Drug Administration criteria for implant surveillance, which includes magnetic resonance imaging, with and without contrast, beginning at 3 years after reconstructive surgery and every 2 years thereafter. Magnetic resonance imaging surveillance not only monitors the implant but also helps monitor the overall chest.
Prepectoral implant placement is not a novel concept, as the first subcutaneous breast reconstructions were essentially prepectoral. However, prepectoral reconstructions performed in the 1960s were limited by the extent of mastectomy, reconstructive technique, technology, and perhaps also by the lower expectations of breast aesthetics. Over the past several decades, great strides have been made in implant designs and reconstructive and soft-tissue augmentation techniques. Mastectomies are now less aggressive with improved understanding of skin flap limitations; thus, the damage to the skin flap and its vasculature are minimized. The availability of devices that assess tissue perfusion has further allowed assessment of perfusion and viability of the skin flap that help guide decisions on the suitability of the prepectoral approach for a particular patient. The availability of acellular dermal matrices that can be used as a layer of vascularized regenerative tissue between the implant and mastectomy flap is a prerequisite for prepectoral placement. Improvement in fat grafting techniques have made fat grafting a routine procedure in breast surgery, thereby allowing the use of adipose tissue to support and augment the soft-tissue volume between the implant and the mastectomy flap. Finally, improvement in implant designs have resulted in highly cohesive, form-stable, and higher-fill implants that are associated with less rippling. It is the combination of all the above factors that have made the prepectoral approach feasible, more than half a decade after the failure of early attempts.
Our preliminary results suggest that the prepectoral approach can lead to predictable outcomes and aesthetically stable reconstructions, at least in the short-term (data available up to 2 years after surgery) (Figs. 1 and 2). There has been no instance of animation deformity or capsular contracture in over 350 reconstructions to date. In addition, postoperative complications have been minimal and comparable in incidence to those reported with the partial muscle coverage technique.16–18 Integral to the success of this approach is our bioengineered breast concept of enhancing soft-tissue coverage using a combination of regenerative scaffold (acellular dermal matrix) and regenerative cells in conjunction with form-stable implants. [See Figure, Supplemental Digital Content 1, which shows a 56-year-old woman (body mass index, 24 kg/m2) with a diagnosis of multifocal right breast ductal carcinoma (estrogen receptor/progesterone receptor-positive). The patient underwent bilateral nipple-sparing mastectomy and immediate two-stage reconstruction with tissue expanders, acellular dermal matrix, fat grafting (170 cc on each side), and a Natrelle Style 410 LX 570-cc implants (Allergan). Preoperative view (first three pictures) and postoperative view at 12 months are shown, http://links.lww.com/PRS/C56.] Volume enhancement is critical for both aesthetics (e.g., masking implant palpability, visibility, and rippling/wrinkling) and functionality of the breast. Thicker flaps are more protective given that small trauma to the breast will not lead to major complications and implant loss. In addition, diligent follow-up of patients to monitor for signs of postoperative complications and their aggressive management is also critical for a successful outcome. We have instituted specific protocols for managing complications in our practices. For skin necrosis, we maintain a lower threshold for intervention than for the partial-muscle coverage technique given the proximity of the skin to the underlying implant. Even minor flap necrosis is débrided and/or excised and rinsed with antibiotic solution before closure. For red breasts suspicious for seroma/infection, we typically perform an ultrasound and follow through with drainage, oral antibiotics, and intravenous antibiotics plus surgical intervention as the case may be (Fig. 3). Any degree of rippling is corrected with further fat grafting and thus selected patients must have adequate donor fat availability.
In addition to producing aesthetically pleasing and predictable outcomes, the prepectoral procedure is also attractive because of its simplicity. It is a less invasive procedure, as it obviates the need to elevate the pectoralis major muscle. With muscle sparing, surgical time is shortened, the requirement for intravenous pain control or a pain pump is diminished, and patients can typically be discharged after 1 night of hospital stay. For patients, it is a less traumatic procedure with less pain and a faster recovery. In the future, patients may be able to be discharged to home on the same day after prepectoral reconstruction.
However, the immediate prepectoral procedure is not suitable for all patients, including in particular patients who have a thin, ischemic, poorly vascularized skin flap after mastectomy; patients with a history of preoperative breast irradiation or uncontrolled diabetes (hemoglobin A1c >7.5 percent); patients who are active smokers, immunocompromised, or obese; and patients who lack fat donor sites (Table 3). In addition, oncologic patients who have late-stage breast cancer, have deep tumor near the pectoralis major muscle, and who are at increased risk of cancer recurrence are also poor candidates for the prepectoral approach. Patients undergoing skin- or nipple-sparing mastectomy can have prepectoral placement, provided that they do not have the identified contraindications. The immediate reconstructive contraindications do not apply to delayed reconstructions, as the latter do not rely on viability of flaps; instead, the overall health of the patient should be considered. Given our early experience with this technique, we have adopted a conservative, cautious approach to indications and continue to work closely with breast surgeons to minimize contraindications. In a few years, it is possible that our list of contraindications may be shorter, but for now we believe it is important to remain cautious. This is very similar to what we have seen with nipple-sparing mastectomies, where the procedure is now being performed on more advanced cancers than originally intended and the indications have expanded in the past 2 years based on experience and new evidence.
The breast reconstructive process is continuously evolving given the increasing expectations of both patients and surgeons for stable aesthetic outcomes with minimal complications and a fast recovery. Whether prepectoral implant placement using the bioengineered breast concept would fulfill these expectations remains to be seen. Evaluation of longer term outcomes will be necessary to ensure the adequacy of the “engineered” soft-tissue coverage. The other issue that must be documented over time is whether the soft-tissue cover of the acellular matrix and added fat maintain adequate thickness and padding over the implant, to justify the cost of the larger pieces of acellular dermal matrix required for total device coverage.
Prepectoral implant-based breast reconstruction is a muscle-sparing procedure that simplifies breast reconstruction. By placing the implant prepectorally, the attendant problems associated with pectoralis muscle elevation are avoided. The success of this approach rests on the bioengineered breast concept wherein highly cohesive, form-stable implants are used in combination with regenerative scaffold and regenerative cells to augment the soft-tissue envelope of the reconstructed breast. Preliminary data from over 350 reconstructions attest to the feasibility of this approach, but long-term data are needed to understand the aesthetic and functional stability of the prepectoral approach.
The authors would like to thank Kalanethee Paul-Pletzer, Ph.D., for providing medical writing support for this article.
2. Gruber RP, Kahn RA, Lash H, Maser MR, Apfelberg DB, Laub DR. Breast reconstruction following mastectomy: A comparison of submuscular and subcutaneous techniques. Plast Reconstr Surg. 1981;67:312317.
3. Spear SL, Schwartz J, Dayan JH, Clemens MW. Outcome assessment of breast distortion following submuscular breast augmentation. Aesthetic Plast Surg. 2009;33:4448.
4. Maxwell GP, Gabriel A. Bioengineered breast: Concept, technique, and preliminary results. Plast Reconstr Surg. 2016;137:415421.
5. Glasberg SB, Light D. AlloDerm and Strattice in breast reconstruction: A comparison and techniques for optimizing outcomes. Plast Reconstr Surg. 2012;129:12231233.
6. Spear SL, Pelletiere CV. Immediate breast reconstruction in two stages using textured, integrated-valve tissue expanders and breast implants. Plast Reconstr Surg. 2004;113:20982103.
7. Serra-Renom JM, Fontdevila J, Monner J, Benito J. Mammary reconstruction using tissue expander and partial detachment of the pectoralis major muscle to expand the lower breast quadrants. Ann Plast Surg. 2004;53:317321.
8. Hammond DC, Capraro PA, Ozolins EB, Arnold JF. Use of a skin-sparing reduction pattern to create a combination skin-muscle flap pocket in immediate breast reconstruction. Plast Reconstr Surg. 2002;110:206211.
9. Breuing KH, Warren SM. Immediate bilateral breast reconstruction with implants and inferolateral AlloDerm slings. Ann Plast Surg. 2005;55:232239.
10. Salzberg CA. Nonexpansive immediate breast reconstruction using human acellular tissue matrix graft (AlloDerm). Ann Plast Surg. 2006;57:15.
11. Zienowicz RJ, Karacaoglu E. Implant-based breast reconstruction with allograft. Plast Reconstr Surg. 2007;120:373381.
12. Spear SL, Parikh PM, Reisin E, Menon NG. Acellular dermis-assisted breast reconstruction. Aesthetic Plast Surg. 2008;32:418425.
13. Breuing KH, Colwell AS. Inferolateral AlloDerm hammock for implant coverage in breast reconstruction. Ann Plast Surg. 2007;59:250255.
14. Vardanian AJ, Clayton JL, Roostaeian J, et al. Comparison of implant-based immediate breast reconstruction with and without acellular dermal matrix. Plast Reconstr Surg. 2011;128:403e410e.
15. Maxwell GP, Storm-Dickerson T, Whitworth P, Rubano C, Gabriel A. Advances in nipple-sparing mastectomy: Oncological safety and incision selection. Aesthet Surg J. 2011;31:310319.
16. Cordeiro PG, McCarthy CM. A single surgeon’s 12-year experience with tissue expander/implant breast reconstruction: Part I. A prospective analysis of early complications. Plast Reconstr Surg. 2006;118:825831.
17. Kim JY, Davila AA, Persing S, et al. A meta-analysis of human acellular dermis and submuscular tissue expander breast reconstruction. Plast Reconstr Surg. 2012;129:2841.
18. Hunsicker LM, Ashikari AY, Berry C, Koch RM, Salzberg CA. Short-term complications associated with acellular dermal matrix-assisted direct-to-implant breast reconstruction. Ann Plast Surg. E-published ahead of print February 5, 2016.
Supplemental Digital Content
Copyright © 2017 by the American Society of Plastic Surgeons