One- and two-stage prepectoral reconstruction with prosthetic devices

Introduction

Oncoplastic treatment of breast cancer, which combines oncologic and reconstructive surgery, has become increasingly popular. Conservative mastectomy, including SSM, NSM, and skin-reducing mastectomy (SRM), are well-established, validated, and widely used procedures for breast cancer treatment; in such cases, immediate breast reconstruction is the current standard.

Ideally, oncoplastic surgery provides aesthetically pleasing results while achieving appropriate oncologic safety. However, a potential pitfall of these oncoplastic techniques is the uncertainty regarding the blood supply to the remaining flaps and the NAC. Post-procedural nipple and skin necrosis rates as high as 38% have been reported. Patients with a large cup size or a previous history of surgery or radiation and active smokers are considered to be at high risk for NSMs and SSMs because these factors are associated with even higher rates of complications.

Several recommendations have been proposed to avoid necrosis of mastectomy flaps and/or NAC. Preservation of adequate flap thickness during mastectomy significantly reduces skin necrosis. However, this is not always possible and depends on the anatomical characteristics of each patient. Performing an oncologically safe mastectomy requires dissection below the superficial layer of the fascia superficialis. The distance between the skin and the gland determines the subcutaneous tissue or “gland envelope” thickness.

Currently, standard film mammograms do not allow for clear identification and measurement of non-glandular breast tissue coverage. In contrast, digital mammography clearly distinguishes gland tissue density from tegument and fat coverage; accordingly, this preoperative imaging modality can determine the coverage thickness, which is the distance between the breast skin and Cooper's ligaments surrounding the gland ( Figs. 20.1–20.3 ). Incision planning, treatment selection, surgical technique, and reconstructive procedures are usually related to the breast volume, tumor characteristics, and surgeons' and patients' preferences; preoperative information regarding breast tissue coverage thickness might highlight the likelihood of postmastectomy flap issues and assist with the planning process, rather than relying on breast volume alone as a guideline.

Adequate fat tissue coverage thickness is one of the most important independent factors in immediate breast reconstruction and flap survival. Anatomically, the vascular network that ensures flap and NAC survival runs between the Cooper's ligaments and the skin. Compression of this vascular network by implant insertion, surgical damage, tissue tension at closure, or extremely thin flaps might endanger vascularization, and such events have been shown to cause tissue damage in the distal parts of the flaps. Therefore, preoperative breast tissue coverage should be considered an important factor in immediate reconstruction.

Indications for prepectoral DTI

The indications for prepectoral DTI are the same as those for subpectoral DTI. Patients need to have optimal skin quality, excellent mastectomy flap perfusion, ideally mild to moderate ptosis and size, and mild to moderate breast size. Skin-reducing mastectomy techniques can be used judiciously in a selective subset of patients with larger ptotic breasts for prepectoral DTI reconstruction.

Patient selection

Preoperative evaluation of gland coverage can help predict the viability of the remaining flaps after conservative mastectomies and select the optimal immediate reconstructive procedure to reduce postoperative coverage complications.

One of the most important factors for the vascularization of the remaining postmastectomy flaps is the preservation of the skin perforators and flap thickness. The thickness of the remaining skin flap after gland resection during conservative mastectomy plays an important role in flap integrity and NAC vitality. Cooper's ligaments separate the mammary gland from the superficial fat and skin tissue layers that contain the vascular plexus, of which the mastectomy flaps are composed. Preoperative information regarding this tissue coverage is therefore of utmost importance to avoid complications associated with immediate reconstruction procedures.

Larson et al. reported differences in the thickness of subcutaneous breast tissue not related to breast volume. Therefore, it could be advantageous to know the thickness of the subcutaneous breast tissue before considering a DTI reconstruction following an NSM.

A more comprehensive indication for a reconstructive method could be evaluated by considering this preoperative information over the possible resulting flap thickness after mastectomy. We propose a breast tissue coverage classification (BTCC) ( Table 20.1 ) based on digital mammogram evidence.

Based on the obtained range of coverage values, a three-type BTCC is as follows:

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  Type 1: <1 cm (poor coverage)

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  Type 2: between 1 and 2 cm (medium coverage)

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  Type 3: >2 cm (good coverage).

This classification may also allow a rational use of materials for individual patients.

We confirmed that the selection of patients with breast subcutaneous tissue coverage above 2 cm, as an evidence of preoperative digital mammogram evaluation, determines an adequate flap for NSM, directly representing the distance between the Cooper's ligaments (the “safe” mastectomy surgical plane) and the skin.

In such patients, an immediate DTI reconstruction could be safely performed.

The possibility of selecting cases for this procedure according to the preoperative digital mammogram showing a superficial tissue thickness of more than 2 cm may help reduce the risk of immediate ischemic complications. Additionally, the use of surgical materials may be evaluated according to this coverage measure. According to our classification, it would be helpful to add supplementary coverage for the reconstruction, such as acellular dermal matrix (ADM), meshes, retropectoral implant placement, and delayed fat grafting for patients in the poor coverage group (type 1). In the medium coverage group (type 2), a two-stage expander-implant reconstruction should be suggested to avoid tension at the flap closure, whereas in the good coverage group (type 3), single-stage DTI prepectoral reconstruction with implants could be performed without any mesh.

The selection of mastectomy and reconstruction procedures should be made jointly by the oncologic and plastic surgeon or by the oncoplastic breast surgeon based on objective preoperative information. We observed that breast tissue coverage and breast volume are independent factors that exist in large breasts with poor coverage and small ones with good coverage. This suggests that preoperative measurement of the breast tissue coverage thickness is important for surgical decisions independent of breast volume. Regardless of breast volume, however, preoperative evaluation of tissue coverage is crucial for surgical planning by both oncologic and plastic surgeons, as this factor is directly related to the risk of flap and NAC ischemia/necrosis. Thin flaps can lead to ischemic complications following mastectomy and reconstructive procedures. Preoperative digital mammography or magnetic resonance imaging (MRI) is therefore potentially useful not only for tumor detection but also as an objective tool to predict the resulting flap thickness, thus improving patient safety.

As a result, preoperative communication between the reconstructive and oncologic surgeons regarding the incision choice and integumentary preservation according to digital mammogram findings might lead to improved outcomes with a decreased rate of complications ( Figs. 20.4–20.5 )

Other patient factors associated with higher postoperative complications in reconstructive surgery include active smoking and a history of previous breast irradiation.

Patients should be fully involved in the decision-making process, and clear information should be provided, including uncertainties and risks of more complex procedures.

Surgical technique

A meticulous surgical technique is essential to preserve the vascular network that guarantees the survival of the skin flap and NAC. Skin flaps are dissected with or without prior infiltration using either blunt or sharp techniques.

The NSM is performed with blunt scissors to dissect the breast gland from the skin flap in the plane of the Scarpa fascia as a first step, and previous infiltration with Klein solution of the whole breast between the gland and the cutaneous coverage is performed with 250 cc per breast. Electrocautery is then used to dissect the gland from the pectoralis major muscle in the second step. With this technique, thermal injury of the skin can be avoided, the best blood supply of the skin flaps can be preserved, and skin perfusion can be protected. Then, the complete breast gland is dissected peripherally with sufficient exposure of the axillary tail. After glandular resection ablation, the volume and weight of the breast gland are measured, and the final implant size is determined according to this information. As most of our patients want their reconstructed breasts to look natural and similar to their original breasts, anatomical implants and implant sizes resembling the removed breast volumes are used.

To improve oncologic safety, reduce ischemic risk, and assure the dissection of the subareolar and periareolar tissue, we perform specific hydrodissection under the NAC, which we find very helpful at this point of practice to remove maximum breasts and ducts. Hydrodissection with Klein solution creates a subdermal plane facilitating NAC dissection and permits a more complete removal of breast tissue in NSM. Such radicality could prove important in the treatment of breast cancer and in BRCA 1/2 mutation carriers because of its potential to reduce the risk of relapse ( Fig. 20.6 ).

Retroareolar nipple biopsy NAC tissue biopsy is also essential to ensure oncological safety. Partial necrosis of the nipple or NAC and loss of sensation are the most frequent complications of this surgery. The balance between oncological safety and preservation of vascularity is vital for obtaining optimal surgical outcomes.

Incision location

From a reconstructive perspective, preservation of the NAC improves aesthetic outcomes without increasing the rate of cancer recurrence. The principal reconstructive benefit of the NSM technique is NAC preservation; however, the NAC is also the most vulnerable anatomical element during the mastectomy and reconstructive procedures. If significant epidermolysis or full-thickness loss of the nipple occurs, there is no advantage in performing an NSM.

A number of incision locations are available to the mastectomy surgeon, including inframammary, lateral, and periareolar approaches. Different studies have identified periareolar incision as a risk factor for nipple necrosis during NSM. In comparison, the lateral or inframammary incision resulted in fewer complications of nipple necrosis.

Knowledge of breast blood supply is fundamental to diminish ischemic complications during conservative mastectomies. Previous scars and radiotherapy must be considered when planning the incision. The second intercostal perforator is dominant in more than 60% of the cases, and the 5th intercostal perforator (AICAP) also has a fundamental role in NAC and lower skin survival. External lateral vascularization was supplied by the lateral thoracic artery. Topographic localization over the skin flaps is important for preserving them during mastectomy ( Fig. 20.7 ).

Incorporating these findings, our recommendation for the NSM approach and subsequent reconstruction is as follows: for patients with small breasts without tumors in the upper outer breast quadrant, an inframammary incision should be used; in cases not meeting these criteria, a lateral incision is recommended.

Use of meshes

Various types of biological and synthetic meshes have been used for prepectoral implant reconstruction. Both partial wrap (anterior) and total wrap techniques are used for prepectoral DTI reconstruction with comparable outcomes. Meshes such as the Braxon mesh is a pre-fashioned mesh that allows total wrap of the implants and helps save operating time.

Complete wrap with flat sheet mesh

The wraparound of the mesh was carried using either a single large piece (if available) or two pieces of mesh anchored using sutures ( Fig. 20.8 ). The mesh forms a complete 360° wrap around the implant, and the mesh edges are sutured using an absorbable suture (e.g., 2-0 Vicryl or PDS) to form a pocket. The mesh implant pocket is secured to the chest wall and, if needed, to the inframammary fold (IMF). This enables adequate anchorage and control of the breast shape and ptosis, thus avoiding implant displacement.