138: Options for Soft Tissue Chest Wall Reconstruction

The bony thorax with its overlying muscles and integument creates a cage that protects the relatively fragile heart, great vessels, lungs, esophagus, and large lymphatics. Disruption of the thorax by trauma, tumor, congenital anomaly, infection, or surgical intervention can have potentially lethal consequences. Advances in cardiac and thoracic surgery have enabled surgeons to operate safely within these cavities. Positive pressure ventilation with the use of selective tubes and bronchial blockers permits surgeons to open the pleural spaces and continue respiration while the pleural cavity is disrupted. Advances in cardiac surgery include cardiopulmonary bypass, intra-aortic balloon pumps, and ventricular assist devices that permit continued or augmented perfusion with oxygenated blood. These advances combined with a better understanding of biomaterials,^1–3 tissue-engineered solutions, and advances in plastic and reconstructive surgery^4–6 have allowed more complex sternal and chest wall defects to be successfully reconstructed. In this chapter we will focus our efforts on the multidisciplinary approach to reconstruction of the chest and highlight the three most common flaps used for large defects: the latissimus dorsi, pectoralis major, and omental flaps.

The chest wall has a robust blood supply provided anteriorly by the internal mammary vessels that arise from the subclavian artery and are connected via intercostals to the aorta. Multiple other arteries including the thoracoacromial trunk, transverse cervical artery, and the thoracodorsal artery provide the blood supply to muscles around the upper chest, back, and shoulders. A thorough understanding of the intricacies of the chest wall vasculature, including angiosomes, will allow the surgeon to design reliable flap coverage for most defects. Occasionally, if regional flaps are insufficient or unavailable, free tissue transfer may be necessary to close selected defects.

Large chest wall defects may benefit from a stable reconstruction of the ribs or rib cartilages to maintain adequate pulmonary function (see also Chapter 137). This is generally performed with a variety of materials including synthetic and biological implants. An understanding of the biomaterial/tissue interface is critical to the proper planning of any reconstructive operation. In addition, the stiffness of the biomaterial should optimally match that of the region being replaced to avoid stress concentrations at the junction between the biomaterial and normal tissue.

Meticulous surgical technique is essential in dissecting flaps and allowing them to survive when transferred. Because of the robust blood supply to the chest skin, many wounds can be closed with moderate tension without breakdown. Many chest wall reconstructive procedures occur before or after radiation therapy. Radiated tissues can be difficult to work with because of increased stiffness and their susceptibility to infection.

Patient Selection

The reconstructive surgeon must carefully match the many possible solutions of a thoracic defect to the needs of the specific patient. Chest wall compliance is a function of age, with older patients developing stiffer costochondral junctions and barrel chests. These patients often can tolerate more options for chest wall reconstruction than a younger patient where movement can result in chest wall instability. Younger patients require careful attention to the donor site and ultimate functional and aesthetic outcome and can tolerate longer, more complicated procedures to achieve these goals. Older, more debilitated patients are better served with a more expeditious and reliable operation that might involve more visible scarring. Chest wall reconstruction is optimally performed in a multidisciplinary setting that often includes reconstructive, thoracic, and cardiac surgery, as well as an experienced anesthesia team. A team that works together often will soon develop a sense for what operations can be safely performed in which patients.

Preoperative Assessment

The reconstructive surgeon needs to evaluate these patients in conjunction with a cardiac or thoracic surgeon to coordinate each portion of the procedure. The nutritional status of the patient as defined by albumin and prealbumin levels can be an important predictor of the ability to heal wounds and achieve a successful closure.⁷ A careful history and examination of the patients with regard to previous surgeries is essential to understand which flaps may not be usable based on previous incisions. Flaps ideally should come from areas that have not been heavily irradiated, so an assessment of where radiation therapy has been given is important. Also, many cancer patients may be on chemotherapy, and operative timing should be coordinated so an operation is not required when the patient is neutropenic.

The majority of thoracic reconstructions can be accomplished with one or a combination of the latissimus dorsi, pectoralis major, and omental flaps. Flaps have an independent blood supply and can be transposed into the defect. They fill dead spaces and allow a three-dimensional vascularized surface to deliver antibiotics, heal tissue, and help prevent direct cutaneous exposure of implanted biomaterials in the event of wound separation.

Latissimus Dorsi Muscle Flap

The latissimus dorsi muscle is the largest muscle in the body. It originates from the thoracic spine and thoracolumbar fascia to the iliac crest and inserts into the humerus (Fig. 138-1). Its major blood supply comes off the thoracodorsal system. The muscle can be accessed through a vertical, horizontal, or oblique incision or endoscopically.⁸ The skin and subcutaneous tissues are dissected off the muscle, and the muscle is then dissected off the chest wall. Large perforators off the paraspinous area and thoracolumbar area can be divided with clips or ties. The thoracodorsal pedicle is identified and preserved. The nerve can be left intact, divided, or crushed depending on the desired function of the muscle. For additional pedicle flap reach, the insertion to the humerus can be divided. If the insertion is divided, care must be taken to avoid tension on the pedicle. Suturing the tendinous insertion to the chest wall at a location that provides protection from tension to the pedicle should suffice and also will avoid rotational kinking that can occur if the flap is dissected to the point that it is only attached to the neurovascular bundle. This large muscle reaches nicely into the chest cavity after removing a portion of the second rib and easily covers the hilum. It also can easily reach the anterior mediastinum to cover the heart. With a skin paddle included with the tissue, it can be a useful flap for breast reconstruction or chest wall reconstruction. The distal portion of the flap can sometimes be unreliable because of vascular insufficiency, and caution therefore needs to be taken when the flap is used for defects that are distal to the costal margin. Although loss of latissimus dorsi function results in negligible functional deficit, a split-latissimus dorsi flap can be used to preserve some of its form and function. For many patients who have undergone a standard posterolateral thoracotomy, this muscle is divided and only the superior portion can be used based on the thoracodorsal blood system. The inferior portion can be used for lower thoracic defects based on perforators near the spine. Closure of this defect is generally accomplished with deep dissolvable sutures. Quilting sutures are preferred by many surgeons to reduce the size of the cavity, thus minimizing the risk of postoperative seroma, which has been reported to occur in 20% to 80% of patients.

Pectoralis Major Muscle Flap

The pectoralis major muscle is the largest anterior chest muscle and can be very versatile in treating a variety of chest defects (Fig. 138-2A). Its primary blood supply is from the thoracoacrominal trunk. Access to the muscle can be made through an incision concealed in the inframammary fold. The skin and subcutaneous tissues are dissected off the muscle and the muscle is taken off the chest wall with electrocautery. The perforating vessels off the internal mammary artery are coagulated or ligated and the thoracoacromial trunk is identified and preserved (Fig. 138-2B). For additional length, the medial and lateral pectoral nerves as well as the insertion into the humerus can be divided. To cover the hilum, the muscle can be brought through a second rib resection anteriorly (Fig. 138-2C). For cervical esophageal reconstruction, overlying skin can be taken with the flap and fashioned into a tube. For anterior mediastinal reconstructions, the muscle can be transposed over the ribs and easily fills the superior portion of the anterior mediastinum. For lower defects, the muscle is often more efficiently transposed on the perforators from the internal mammary artery system. In this case, the thoracoacromial vascular pedicle and humeral insertion is divided and the muscle is “turned over” medially to fill the defect. As there is usually a perforator between each costal cartilage, it is possible to divide the muscle along its fibers and have multiple small segments of the muscle for filling complex defects of the anterior mediastinum. The pectoralis major muscle can also be split based on perforator anatomy to more accurately fill specific defects.

Omental Flap

The omentum is a large vascularized fatty structure in the abdominal cavity that originates from the greater curvature of the stomach and is adherent to and drapes over the transverse colon (Fig. 138-3). It connects to the spleen on the left side. Access to the omentum is most easily performed through a small upper midline incision, although it is possible to reach from the anterior mediastinum, through the diaphragm or to dissect it endoscopically. The first step in harvest is to release any abdominal adhesions to the omentum. Making counter incisions over previous scars, such as appendectomy incisions, can facilitate release. The omentum and transverse colon are then brought into view and the omentum meticulously dissected off the transverse colon, preserving both the vasculature to the colon (the transverse colonic mesentery) and the vasculature arcades of the omentum. After some dissection, the lesser sac is entered. Generally, the omentum is less stuck to the transverse colonic mesentery on the left side than the right, in most cases making it easier to start the dissection on the left side. Extensions to the spleen are divided with clamps and ties or with an advanced coagulation method.

For anterior mediastinal defects, this amount of dissection may be sufficient. If additional length is needed, it can be acquired from either the right or left gastroepiploic system. Each system should be assessed for patency before dividing any vessels to assure adequate flow to the omental flap. Each of the gastric perforators is individually ligated while checking the pulse within the gastroepiploic system. Once completed, this dissection gives the omentum several inches more of length, permitting a large segment of vascularized material to be placed virtually anywhere within the chest cavity. The omentum can be brought through an anterior defect in the diaphragm to reach anterior mediastinum and sternal debridement defects. Anterior chest wall defects with intact sternum usually require the pedicle of the omental flap to pass through a midline subxiphoid laparotomy defect. Closure of the abdominal cavity needs to be performed with care to make sure that there is no compression on the pedicle and to minimize the risk of herniation.

Postoperative Care

Initial care of complex reconstructions of the chest most reliably occurs in an intensive care setting by staff familiar with treating thoracic surgical patients. Invasive hemodynamic monitoring, ventilatory support, pleural drainage catheters, monitoring of fluids and renal function are essential to avoid morbidity and mortality. Pain relief using narcotics, nonsteroidal anti-inflammatory agents and regional epidural blocks can greatly aid patient recovery. Deep venous thrombosis prophylaxis is essential. For free tissue transfer operations, a monitoring system that is well understood in the hospital is essential for flap success. Even in the best centers, up to 5% of patients with free tissue transfer will need to return to the operating room for potential vascular thrombosis and revision of the microanastomosis. If discovered early, there is a high likelihood of correcting this problem.

Thoracic reconstruction allows treatment of large and complex defects. The combination of new technology such as advanced biomaterials, free tissue transfer, advanced wound care modalities, and vascularized tissue transfer have allowed these defects to routinely be treated with low morbidity and mortality. The complexity of these operations requires a team approach including a cardiac or thoracic surgeon, a plastic surgeon, and intensive care specialists to provide advanced life support measures in the postoperative period. Advances in plastic surgery including better understanding of anatomy, improved biomaterials, and tissue-engineered solutions will undoubtedly improve the ability to reconstruct these challenging defects in the future.

Harvesting the latissimus dorsi muscle flap for chest wall reconstruction will weaken arm adduction but is generally well tolerated. Seroma is common after reconstruction with latissimus dorsi muscle and is best treated with serial aspiration and/or drain reinsertion. Pectoralis muscle flaps will cause some weakness in adduction and internal rotation of the arm. The turnover flap can cause a significant contour deformity. Given the nature and location of omental flaps, the risk is increased for bowel obstruction, hernia formation, or abdominal dehiscence. For infections of the chest, the most common complication seen is inadequate debridement of necrotic bone or cartilage fragments leading to recurrent infection.

Chest well reconstruction requires a multidisciplinary approach to patient selection and operative intervention as well as close postoperative monitoring. Advances in plastic surgery have made pedicled flap closure quite reliable. Free tissue transfer is sometimes needed but can generally be avoided by the use of local or regional flaps.

Given the importance of obtaining negative margins after resection of a chest wall tumor, the ability to resect the necessary chest wall and reconstruct the resultant defect with a variety of tissue flaps is of utmost importance for both the functional and cosmetic benefit of the patient. Early involvement of the plastic surgeon in the planning stages is critical, particularly for planning of the incision to spare as much viable muscle as possible. This chapter highlights the importance of multidisciplinary teamwork for the benefit of the patient.