Recent advancements in both mastectomy techniques and breast reconstruction practices ameliorated many of the historical concerns of reconstruction in the subcutaneous plane and allowed for a renewed push toward wider acceptance of prepectoral prosthetic-based breast reconstruction (PBBR). Much of the apprehension with prepectoral reconstruction lies in the fact that early mastectomy flaps were thin, poorly vascularized, and unpredictable, which could lead to tissue ischemia, delayed wound healing, and ultimately prosthesis exposure. By placing the prosthetic in a retropectoral plane, reconstructive surgeons created a well-vascularized tissue envelope with which to develop a breast mound through staged tissue expansion. The relatively recent introduction of skin-sparing and nipple-sparing mastectomy techniques has led to more ample skin envelopes for reconstruction and obviated this need for the total submuscular plane and, in many cases, tissue expansion altogether.1–4 In addition, new tools have emerged allowing for real-time assessment of tissue perfusion. Fluorescence angiography with indocyanine green allows for intraoperative visualization of compromised mastectomy flaps and has led to a decrease in skin flap necrosis.5,6 Similarly, reconstructive outcomes have improved with the use of acellular dermal matrices (ADMs) leading to better esthetic results and decreased rates of implant rippling and capsular contracture.7–12
The theoretical advantages of prepectoral PBBR over partial or total submuscular reconstruction include reduced postoperative pain and faster postoperative recovery. From an esthetic standpoint, postoperative animation deformity of the pectoralis muscle is eliminated. Furthermore, anatomically replacing the native subcutaneous breast tissue with an implant in the same position enhances overall breast esthetics and provides greater symmetry in unilateral cases. As prepectoral PBBR gains notoriety and acceptance as an alterative to the partial or total submuscular reconstruction, adjustments to surgical technique will allow for a more optimal result in terms of esthetics and patient satisfaction.
Previously published reports on prepectoral PBBR highlight 2 potential drawbacks to its use: (1) a conspicuous and palpable superior implant edge and (2) upper-pole implant rippling.13 Traditionally, these untoward effects are addressed by means of fat grafting, which requires further surgical intervention and is particularly difficult in thin patients. We propose “The P1 Method,” which incorporates a superiorly based slip of pectoralis muscle in prepectoral PBBR as a novel technique that affords the patient all of the benefits of prepectoral reconstruction while capitalizing on the known advantages of muscle coverage in the upper pole. Use of this technique allows for prepectoral PBBR to be undertaken in thin patients without ample donor sites for subsequent fat grafting, reducing the need for reoperation and providing greater implant support.
A retrospective review of all patients undergoing P1 PBBR at our institution from December 2015 through September 2016 by a single surgeon (T.A.P.) was undertaken. Patients were offered prepectoral breast reconstruction if they desired prosthetic-based reconstruction and did not meet several relative contraindications. These contraindications include patients with morbid obesity, with tumors near the pectoralis muscle or those invading the pectoralis fascia, with diagnosis of a connective tissue disease, with prior chest wall irradiation, with immunocompromised state, or with uncontrolled diabetes mellitus, or patients who were active smokers. Patients who underwent P1 prepectoral breast reconstruction, with a small slip of superior muscle, were included for review in this study based on the plane of their prosthetic device after breast reconstruction (Table 1). Those whose implant was placed in a complete prepectoral plane were labeled “P0” and were excluded from data collection. Data pertaining to patient demographics, mastectomy type/weight, indications for mastectomy, need for either preoperative or postoperative adjuvant therapy, implant type, and esthetic outcomes were collected. Patients were seen in follow-up at 1 week postoperatively and then at 3-month intervals for the duration of the study. A thorough breast examination included assessment for animation deformity, and capsular contracture was performed at each follow-up visit. Clinical photographs were taken by a single medical photographer under controlled studio conditions with standardized lighting, lens, and subject distance. Subjects were photographed from the frontal, three quarter oblique, and lateral views while standing in repose. Images were taken at each follow-up visit. Preoperative and postoperative clinical images were blinded to reconstructive modality and were analyzed by multiple reviewers (T.A.P., J.M.E., O.A.A.) for evidence of conspicuous superior implant edge or implant rippling.
The P1 Method: Surgical Technique
After successful completion of mastectomies by the breast oncology team, adequate perfusion to the mastectomy skin flaps is assessed clinically and confirmed via indocyanine green angiography (SPY Elite; Novadaq Technologies, Inc, Toronto, Canada). Tissue perfusion is considered adequate if there are no clinical signs of venous congestion or ischemia. Based on the SPY images, the decision is made to proceed with direct-to-implant (DTI) reconstruction or proceed with placement of a tissue expander. A preoperative discussion regarding interoperative decision making, based on SPY data, is carried out with each patient at her initial consult. The P1 prepectoral plane is then created by elevating a 2-cm, partial-thickness slip of pectoralis major muscle parallel to its fibers from the sternal edge to the lateral margin of the muscle (Fig. 1). This slip of muscle is created at the superior-most aspect of the pectoralis muscle, approximately 2 cm caudal to the clavicle, and is created at a standard width of 2 cm regardless of implant height in an effort to minimize potential for future animation. Careful attention is given to remain partial thickness to avoid the subpectoral fat pad, which contains the thoracoacromial vascular bundle. Blunt dissection laterally is also recommended to avoid vascular pedicle injury. The muscle is not disinserted from the sternum and the dissection proceeds atraumatically. A sheet of ADM (8 × 16 or 8 × 20 cm) is prepared and attached to the inferior edge of pectoralis muscle with running 3–0 Vicryl suture, which now serves as the leading edge of an ADM curtain (Fig. 2). After attaching the ADM to the pectoralis muscle slip, the pocket is thoroughly irrigated. A highly cohesive, gel implant is inserted under the ADM and wedged into position deep to the muscle slip superiorly but anterior to the bulk of pectoralis muscle, which remains in its anatomic position (Fig. 3). Alternatively, a tissue expander may be placed at this time if the patient is to undergo 2-stage reconstruction. The ADM is then secured to the chest wall with interrupted 3–0 Vicryl suture at the desired level of the inframammary fold and lateral breast margin. Careful attention is given to secure the ADM appropriately to provide enough lateral support to keep the implant in a medial position. Lack of inferolateral support may result in superomedial rippling. Before closing the wound, a 15F Blake drain is placed between the ADM and the mastectomy flap and brought out through a lateral stab incision. With the incisions tailor tacked, the patient is put in the sitting position to check for appropriate shape and symmetry. The wound is closed in layers with 3–0 Monocryl suture.
Fifty patients (93 breasts) were identified who underwent P1 prepectoral PBBR (Table 2). Mean final follow-up was 63 weeks (range, 53–85 weeks). The mean age at time of reconstruction was 46.4 years (range, 27–71 years), whereas body mass index was 23.56 kg/m2 (range, 18–40.6 kg/m2). No patients had a diagnosis of diabetes mellitus or were active smokers during the study period, whereas 16 patients were former tobacco smokers. Three patients (6.0%) underwent preoperative chemotherapy, 6 patients (12.0%) underwent postoperative chemotherapy, and 3 patients (6.0%) underwent postoperative radiation. Seven patients (14%) received postoperative hormonal therapy. Two patients who had undergone bilateral DTI reconstruction (4 breasts; 4.3%) were found to have a noticeable superior implant edge at final follow-up. One of these patients successfully underwent fat grafting in a separate procedure to address her noticeable superior implant edge, which the other patient declined further intervention. No other patient in this series underwent fat grafting at any point during her reconstructive process (Table 3). No patient experienced postoperative animation deformity (Fig. 4; see Video, Supplemental Digital Content 1, http://links.lww.com/SAP/A269, which demonstrates the absence of postoperative animation deformity).
Despite its introduction by Snyderman and Guthrie14 over 40 years ago, subcutaneous breast reconstruction was not widely adopted due to high rates of mastectomy skin flap necrosis, implant extrusion, and capsular contracture.15–17 To mitigate these concerns, surgeons favored a submuscular plane either with total muscle coverage of both pectoralis major and serratus muscles (P3) or with a partial submuscular approach facilitated by an inferolaterally placed ADM sling (P2). The intent with these techniques was to provide durable soft tissue coverage of the implant that obscures the superomedial implant edge, offers an extra layer of coverage in settings of compromised wound healing, and potentially prevents or minimizes capsular contracture. The limitations of submuscular techniques were evident, however, in increased operative time, increased postoperative pain, implant dislocation/malposition, and animation deformity.18–20
As prosthetic-based reconstruction continues to dominate most breast reconstructions in the United States, constant assessment and adaptation of safe, reproducible surgical technique is necessary to achieve increased patient satisfaction and improved esthetic results.21 Prepectoral breast reconstruction is the next step in the evolution of PBBR, allowing for decreased operative time, decreased postoperative pain, more rapid recovery, a natural breast shape, and elimination of animation deformity compared with a submuscular approach.
The case for prepectoral PBBR is currently evolving, with increasing evidence pointing toward its safety, reliability, and perceived benefits over other approaches.22,23 Although long-term follow-up is lacking, preliminary reports show promise. Reitsamer and Peintinger24 reported on 22 cases of immediate DTI prepectoral breast reconstructions after nipple-sparing mastectomies with no cases of infection, implant dislocation, or grade III or IV capsular contracture after 6 months of follow-up. Bernini et al25 built on these data and compared 34 retropectoral with 35 prepectoral reconstructions at more than 2 years of follow-up, noting no significant difference in implant failure between the groups and a significantly improved esthetic outcome in the prepectoral cohort. Most recently, a large cohort of 353 prepectoral reconstructions has been reported with a 5% complication rate with up to 26-month follow-up.26
The benefits of prepectoral PBBR on esthetic outcomes are also noted in the literature and further supported by our findings. Hammond et al13 demonstrated the ability of the subcutaneous plane to treat animation deformity in their experience converting reconstructions from a submuscular to a prepectoral plane. Similarly, we found that no patient undergoing P1 prepectoral reconstruction experienced postoperative animation deformity in our study. A visibly obvious superior implant edge and superomedial implant rippling, particularly with round implants, are known potentialities of reconstruction in the subcutaneous plane, with subsequent fat grafting often needed to mask these effects (Figs. 5A, B).25,26 The P1 Method described here successfully eliminates these effects and offers a more cosmetic superior pole (Figs. 5C, D). In our series, no patient undergoing a P1 reconstruction had implant rippling at final follow-up and only 2 patients presented with a visible superior implant edge. In addition to the use of a highly cohesive gel implant, these results are likely due to the use of the leading edge of pectoralis muscle to mask the chest wall–implant interface superiorly. This construct not only blunts the superomedial edge of the implant but also provides for a more robust anchor for the ADM sling that enhances inferolateral support of the prosthesis and further reduces rippling at the opposing superomedial edge. In addition, our technique deviates from other published reports in that only the anterior and inferior aspects of the implant are wrapped in ADM vs a complete encapsulation of the prosthetic.26
We believe this modification to be superior for several reasons: (1) it allows for more control in defining the inferior and lateral mammary folds; (2) it promotes posterior implant adherence to the underlying muscle, thus decreasing the risk of implant rotation and bottoming out of highly cohesive anatomically shaped implants within the breast pocket; and (3) the technique used a single moderately sized piece of ADM rather than multiple larger pieces needed for a 360-degree wrap of the entire implant. We believe this to be of utmost importance in today's economic environment and believe that egregious use of ADM in PBBR is fiscally unsustainable. Finally, use of this technique is particularly helpful in slender patients with thin skin envelopes who would otherwise be unable to undergo fat grafting to augment flap thickness due to limited donor sites.
Limitations to this study include a small sample size, limited follow-up, and lack of a control, which reduce the power of our conclusions. Although measures were taken to standardize assessment of esthetic outcomes, these are inherently subjective and dependent on the reviewer(s). Another concern of all prepectoral reconstructions is the potential for capsular contracture. Previous reports describe an incidence of Baker grade III or IV capsular contracture of greater than 20% requiring reintervention.27 Unfortunately, our current study lacks longer term follow-up to adequately assess rates of capsular contracture, with further investigation necessary. The use of ADM in the creation of the prepectoral pocket will hopefully aid in the prevention of capsular contracture. Acellular dermal matrix has previously been shown to be effective in preventing recurrence in revision reconstruction for Baker grade III and IV capsular contracture.28 Nevertheless, we believe that the preliminary results of this novel technique show a viable alternative to standard prepectoral PBBR in patients prone to contour deformities and rippling of the superomedial implant edge. Future investigation into long-term outcomes including objective measures of patient satisfaction and postoperative pain will be necessary to demonstrate the superior value of this technique.
Prepectoral PBBR is an increasingly popular reconstructive modality that may allow for decreased operative times, more rapid postoperative recovery, and overall improved patient satisfaction. Known limitations of this technique include a visible superior implant edge and implant rippling. We propose a novel muscle-sparing technique modification, The P1 Method, which incorporates a partial-thickness slip of pectoralis major muscle in an otherwise prepectoral plane to mask the superomedial edge of the prosthesis. Our results show improved cosmesis and a more esthetic result when compared with a true prepectoral breast reconstruction. Long-term follow-up is needed to assess the viability of this technique.
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