Postoperative morbidity and mortality associated with chest wall resection have been reported to range from 8% to 27% in various series.30 Stability and dynamic elasticity of the thorax are required to support the mechanics of normal respiratory function. Extirpation of a locally advanced or recurrent breast cancer often involves resection of ribs, sternum, adjacent chest wall musculature, lung, pericardium, and thymus. Chest wall reconstruction thus often requires recreation of both skeletal and soft-tissue components. Reconstruction following simple or MRM involves both immediate and delayed reconstructive options; reconstruction following RM or ERM, however, presents unique challenges, as the aims are not only aesthetic but functional. When skin graft is utilized for closure following a RM for LABC, the appearance of the graft is unaesthetic and less stable compared with more complex reconstructive methods (Fig. 68-2). Respiratory disturbance after resection of the anterior chest wall is a major problem, and different techniques of chest wall reconstruction have been described. A reconstructed chest wall should prevent paradoxical movement of the thorax, protect underlying mediastinal structures, and be immunologically inert as well as translucent on chest radiograph. The anatomic site and size of the defect must also be taken into consideration when choosing the materials and technique. Figure 68-3 describes the reconstructive ladder of increasingly complex approaches that can be applied to the reconstruction of chest wall defects.
A skin graft may be an appropriate reconstructive option for defects limited to the skin and subcutaneous tissues. Placed over a greater omental flap, a split-thickness skin graft can be used to resurface the chest wall.42 Likewise, skin grafts may also be used to assist with primary donor site closure after harvesting myocutaneous flaps for chest wall coverage.
The process of engraftment involves revascularization of the skin graft, as the graft initially has no vascular connection and survives via plasma imbibition. The process of revascularization commences approximately 48 hours after graft placement, but graft take may be compromised in a radiated wound bed. This process can be hastened with use of the vacuum-assisted closure (VAC) device (Kinetic Concepts Inc, San Antonio, Texas), which is placed at the time of the initial operation, left in place over the skin graft for 5 days, and then removed at the bedside.43,44 The VAC not only protects the graft in the wound bed but provides a means to improve the adherence of skin grafts in compromised tissues, thus expediting wound closure. Disadvantages of using a skin graft include its propensity to contract and provide a far less aesthetic and durable form of coverage than a vascularized flap.
Various techniques have been used to restore chest wall stability and recreate the chest wall scaffold with the aim of limiting flap movement and consequent paradoxical respiration. The need for a skeletal reconstruction depends on the size and site of the resection; that is, skeletal reconstruction is necessary in cases of removal of the sternum and the anterior and lateral tracts of the ribs, but it may not be necessary for the repair of posterior wall defects entirely covered by the scapula or if the defect can be stabilized by the action of adjacent muscles. While traditionally all sternal defects with greater than 2 adjacent ribs were deemed necessary for rigid stabilization these considerations are evolving. Many authors believe that defects of the sternal and posterior walls need to be stabilized less frequently than anterior or lateral defects.45 Options include the use of autogenous bone grafts, autogenous fascia lata grafts, and numerous synthetic materials, alone or in various combinations.
A spectrum of prosthetic materials may be used for chest wall reconstruction, including metal plates, stainless steel mesh, absorbable mesh (Vicryl mesh, Johnson & Johnson, New Brunswick, New Jersey), nonabsorbable polypropylene mesh (Marlex mesh, Chevron Phillips Chemical, Woodlands, Texas; Prolene mesh, Ethicon, Somerville, New Jersey), and nonporous prosthetic mesh (Gore-Tex mesh; W L. Gore & Associates, Newark, Delaware). The use of synthetic materials is often necessary when reconstructing locally advanced or locally recurrent cancers involving the chest wall (Fig. 68-4). Rigid prosthetic materials, both permanent and absorbable, while less commonly used, may be needed in larger defects (resin plates, methylmethacrylate, and hydroxyapatites combined with tricalcium phosphate).
Locally recurrent breast cancer with erosion into the chest wall (A). Reconstruction of the chest wall with a prosthetic mesh (B) and subsequent rectus abdominis myocutaneous flap (C) are noted.
Prosthetic mesh is easy to handle and can be sutured under tension, thus improving the stability of the thoracic wall.
Gore-Tex has the advantage of being impermeable to air and liquids, but it is very expensive. More importantly, Gor-Tex does not allow for tissue penetration and has a greatly increased rate of seroma formation and infection even late postoperatively and is accordingly less feasible in reconstructive application; porous mesh initially allows passage of fluid through the prostheses, and then tissue ingrowth favors their incorporation into neighboring structures. Vicryl mesh, as it is absorbable, is usually only considered a temporary measure. While a foreign body, vicryl allows tissue ingrowth, making significant complications rare. Polypropylene meshes are the most widely used because of their resistance, manageability, and tolerability over time. Marlex and Prolene are both polypropylene and inert; the difference is that the former has a double and the latter a single layer: when Prolene is extended, it remains rigid in all directions, whereas Marlex is rigid in only one direction. After a total sternectomy or a broad resection including the lateral portion of the thoracic wall and more than 4 ribs, a sandwiched polypropylene and methacrylate mesh offers the best results in terms of stability, intrathoracic organ protection, and pulmonary expansion, but with the utilization of methacrylate the incidence of seroma and complications increase. Accordingly, some authors prefer using prostheses or simple muscle flaps without rigid supports.33,34,45
When the inferior part of the sternum is resected, use of a rigid prosthesis has been advocated to prevent paradoxical movement of the thorax. In contrast, when only the manubrium is resected, soft mesh can be used.46 In patients who have undergone previous mastectomy, there is little subcutaneous tissue remaining over the chest wall. Likewise, radiotherapy has been demonstrated to impair wound healing with resultant skin ulceration, especially with a foreign body or prosthetic material. This has become a challenge for reconstruction. While placement of a Prolene mesh over the surface of the methylmethacrylate has been suggested to aid in skin incorporation with a rigid nonporous foreign body in several studies citing increased success of methylmethacrylate covered on adjacent sites with Prolene mesh, it must be remembered that adequate soft-tissue cover is imperative to insure successful application of such.47,48 In addition, while Gore-Tex mesh has been utilized to cover the heart or in diaphragmatic repairs in cases of broad pericardial and adjacent resections, it must be remembered that these materials remain a foreign body and that they must have adequate soft-tissue coverage or even in the late postoperative course, exposure or compromise of these tissues can result in severe infectious complications that may compromise the patient's health and minimally require removal of the prosthetic material.
Accordingly, the role of newer prosthetic materials that are biocompatible so called bioprosthetic materials that become completely incorporated into the local healing wound are encouraging. These newer prosthetic materials may stem from either human cadaveric dermis (eg, Alloderm, Lifecell, Houston, Texas) or bovine or porcine material (eg, Stratus, Lifecell, Houston, Texas). These materials have been utilized successfully for abdominal wall reconstruction and have found a role increasingly in chest wall applications as well. Currently, however, long-term rigidity and the overall strength of these materials is unclear, as well as the potential for some long-term reabsorbtion. However, these appear to be encouraging materials in application for general truck reconstruction. The utilization for bone grafts and other biological materials in a nonvascularized setting has not demonstrated any improved efficacy in terms of incorporation or infectious complications compared to synthetic materials, and accordingly, due to their more expensive nature and more limited source and volume available for reconstruction, have not played a role even in more recent applications of chest wall deformity reconstruction. It is important to remember that the combination of prosthetic materials with their easy availability but potential for infection and delayed incorporation is most efficaciously employed with the combination of adequate soft-tissue coverage, and this usually involves the application of a muscle or myocutaneous flap in the setting of prior radiation in order to minimize the potential for wound-related complications.