135: Chest Wall Resection and Reconstruction

Chest wall tumors are uncommon malignancies, whether primary or secondary in nature. Nevertheless, nearly every thoracic surgeon eventually will be asked to evaluate one of these tumors in clinical practice. It is estimated that only 500 index cases of primary malignant chest wall tumors occur in the United States annually,¹ in addition to secondary chest wall tumors, which are, most notably, those related to recurrent breast cancer. Given this relatively low incidence, no one surgeon or surgical group could be expected to have an extensive experience with this tumor type. Having a working knowledge of the surgical principles underlying the management of uncommon chest wall tumors therefore is all the more relevant.

The more common primary chest wall tumors are listed in Table 135-1. Although most of these tumors in the pediatric population are malignant, only approximately half of these tumors are malignant in adults.

The overriding technical principle of chest wall surgery is similar to that of tracheal surgery. Specifically, the procedure consists of two separate but equally important parts – resection and reconstruction – and the technical considerations of each must be assessed independently.

With regard to resection, it is imperative to establish first whether the tumor is primary or metastatic, and if primary, whether it is malignant or benign. This determination may be clear from the patient's history and certain radiographic characteristics of the tumor, but a tissue diagnosis is important for several reasons. If the tumor is benign, an overly aggressive resection and complex reconstruction may not be needed. Alternatively, if the tumor is malignant, one of several different treatment strategies may be required. For example, some of these tumors (e.g., osteosarcoma and plasmacytoma) are best treated nonoperatively initially. Other primary malignant chest wall tumors (e.g., primitive neuroectodermal tumors and some sarcomas) may benefit from induction therapy before a planned surgical resection. Thus, establishing a tissue diagnosis is the first important step in the treatment algorithm for chest wall tumors.

The diagnostic technique selected for biopsy also must adhere to standard oncologic principles. The biopsy site must be placed in a location that can be incorporated into the planned resection specimen. Most chest wall lesions that arise from bone, cartilage, or soft tissues of the chest wall are amenable to diagnosis by core needle biopsy. On the rare occasion that core needle biopsy is not possible or is nondiagnostic, incisional biopsy can be performed, provided that the incision is placed within the margins of the resection specimen, as mentioned earlier. Excisional biopsy also can be used for smaller lesions (<3 cm), and if such lesions are later determined to be malignant, a wider local excision that incorporates the old surgical scar can be performed as a separate procedure.

Resectability represents another important oncologic principle, and it is addressed after the tissue diagnosis has been established. Typically, the determination of resectability involves a radiographic assessment of the involved anatomic structures. If it is determined that resection is possible, the surgeon must decide how the resulting skeletal defect will be handled and whether any additional soft tissue coverage will be required. If it is likely that a muscle flap or omentum or a split-thickness skin graft will be needed, a careful assessment of the suitability of the various tissues and flaps should be made. This assessment is often made with the assistance of a plastic surgeon both familiar and comfortable with soft tissue reconstruction of chest wall defects. The planned resection strategy should ensure a complete R₀ resection if at all possible. With advances in chest wall reconstruction (both skeletal and soft tissue) and some intraoperative creativity, nearly any postresection chest wall defect can be managed successfully. Thus the size of a resulting chest wall defect has little, if anything, to do with the resectability of the tumor or extent of the planned resection.

From both a technical and an oncologic perspective, it is important to have an adequate surgical margin around the tumor. This typically requires resection of one uninvolved rib above and below the ribs invaded by the malignant tumor. The medial and lateral margins of resection should be at least 4 to 6 cm. Several reports have documented the importance of a wide local excision (margin of at least 4 cm) resulting in increased disease-free and overall survivals.^2,3 For tumors located in the sternum, the sternum must be removed, although the manubrium may be spared if the tumor affects only the body. The converse is true for isolated manubrial lesions. Additionally, sternal tumors require removal of at least 2 to 3 cm of costal cartilage laterally to ensure R₀ resection. If possible, the upper aspect of the manubrium should be preserved because it provides for the majority of anterior chest wall stability.⁴ Resection of overlying soft tissue and skin is mandatory if there is any suspicion of tumor involvement.

An essential part of the treatment algorithm is the need for case discussion, including careful review of the pathology in the context of a multidisciplinary tumor conference. Such discussion provides the opportunity for medical and radiation oncologists to examine their potential roles in the treatment plan. This exchange is particularly important if either induction chemotherapy or catheter placement for intraoperative brachytherapy is being considered. In addition, multidisciplinary review of the staging studies and pathology ensures the appropriateness of the treatment plan.

Most benign and malignant chest wall tumors are managed with complete surgical resection. For example, the primary treatment for chondrosarcoma, the most common malignant chest wall tumor, is wide local excision. These lesions are highly chemoresistant and have limited sensitivity to radiation. Selected tumors, however, are better managed with adjuvant therapies.

Induction chemotherapy appears to play a role in the management of some primary chest wall tumors. On the basis of data from extremity sarcoma studies, preoperative Adriamycin-based chemotherapy is used in patients with primitive neuroectodermal tumors and for some soft tissue sarcomas.^5,6 After restaging, wide surgical excision is performed, and many patients complete an additional course of adjuvant chemotherapy secondary to the high rate of systemic failure observed with surgery alone for tumors of this type.⁷

Adjuvant external beam radiation for all primary chest wall tumors typically is reserved for R₁ or R₂ resections or in cases where the margin, while negative, lies close to the tumor.⁸ For instance, the rate of recurrence with an R₁ resection of a desmoid tumor of the chest wall is 90%.⁹ In contrast, patients with R₀ resection for a desmoid tumor have a recurrence rate of 27%, and none of the patients who received adjuvant radiation with an R₀ resection developed a recurrence. This suggests that adjuvant radiation may be reasonable in all patients with a desmoid tumor regardless of margin status. The role of adjuvant brachytherapy in the treatment of soft tissue sarcomas of the chest wall is limited by a greater incidence of regional recurrences compared with in-field recurrences. Thus external beam therapy, which covers a larger region of the tumor bed, is preferred.¹⁰ On the other hand, brachytherapy is a useful adjunct to surgical resection for a tumor that has been irradiated previously.

For several tumors, the role of surgery is purely diagnostic. Plasmacytoma is a prime example. These tumors are associated most commonly with multiple myeloma, and even if the patient has no current clinical or laboratory evidence of the disease, he or she frequently develops the disease years later. Therefore, isolated chest wall plasmacytomas typically are treated with external beam radiation alone with very good results. Similar to plasmacytomas, osteosarcomas are often metastatic deposits from long bone (e.g., tibia, femur, or humerus) primaries, although primary chest wall osteosarcomas can arise from the ribs. Regardless of the origin, once the diagnosis is established, both types are treated initially with Adriamycin-based multidrug chemotherapy. Residual primary chest wall osteosarcomas should be resected with wide margins after restaging studies demonstrate the absence of metastatic disease.

After the tissue diagnosis has been established, the patient must be assessed for operability. This process necessitates evaluation of the patient's cardiopulmonary status, age, comorbidities, and performance status.

Once it is clear that the patient is operable, a careful radiographic assessment of the stage and local extent of the tumor is performed. All patients need a CT scan of the chest and upper abdomen, and many will have a PET scan as well. There are few data on the use of PET scans for primary chest wall tumors, particularly those arising from bone or cartilage, but extrapolation from other solid-tumor malignancies suggests that they may be beneficial, particularly with PET-avid tumor types known to metastasize early. Pertinent information supplied from the CT images includes the locoregional extent of the tumor, as well as its proximity to the mediastinum, vertebral bodies, and diaphragm. CT scan also may suggest the presence or absence of metastatic disease in the lung, liver, or adrenals. MRI is reserved for tumors located close to the brachial plexus and subclavian vessels and to resolve any questions about direct involvement of the great vessels or extension into the intervertebral foramina. For soft tissue tumors of the chest wall, it may be difficult to know with certainty if there is bony involvement. No roentgenographic study can definitively include or exclude bone involvement. If the patient has chest wall pain at the tumor site, there is at least an 80% likelihood that bone is involved.

If it appears that the tumor is growing into the underlying lung tissue and that a lung resection may be required, pulmonary function studies also should be performed. If the patient has had a prior surgical procedure, it is imperative to obtain the old operative notes. Likewise, if the patient has received preoperative external beam radiation, the dose and the fields need to be identified before planning the resection and, more particularly, the reconstruction. It is wise to perform a nutritional assessment of the patient and to strongly encourage smoking cessation if applicable. Finally, outpatient consultation with plastic and neurosurgical colleagues can be very helpful, particularly if removal of the tumor requires an extended resection (e.g., vertebral body) or a complex soft tissue reconstruction.

Anesthesia

General anesthesia usually is provided through a single-lumen endotracheal tube. If there is concern that concomitant pulmonary resection or diaphragm reconstruction may be required, a double-lumen tube should be placed. An epidural catheter is used routinely to help manage postoperative pain. Patient positioning is critical because there is frequently a need for access to the abdomen, lower back, flank area, and anterior chest wall. Correct patient positioning and incision planning are facilitated in more complex cases by the presence of other members of the multidisciplinary team, who, if needed, can be called on for their input. This is particularly important if plastic surgery assistance is needed for muscle flap harvest and transposition. Concurrent with patient positioning, the patient should receive prophylactic IV antibiotics.

Chest Wall Resection

All previous incisional biopsy sites or old surgical scars need to be incorporated into the planned resection specimen. The overlying skin does not need to be excised if it is viable and free of tumor. If there is a history of significant radiation with obvious skin changes, however, the skin should be excised back to nonradiated, viable skin and underlying soft tissue. The surgical dissection and resection of a chest wall tumor are guided by the principle that a tumor should be palpated but not seen. Thus a wide (4 cm or more) margin of grossly normal soft tissue around the tumor is required as the dissection plane is being developed. This margin may include portions of the overlying chest wall musculature. The extent of chest wall or sternal resection has been discussed previously. It is worth emphasizing the importance of achieving a complete R₀ resection and obtaining the necessary surgical margins despite temptations to “limit” the resulting chest wall defect.

The pleural cavity should be entered away from the tumor, and the lung should be inspected and palpated for any nodules suspicious for metastatic disease (Fig. 135-1). This is particularly important with soft tissue sarcomas. It is not uncommon for these tumors to adhere to or directly involve the underlying lung parenchyma. Usually a wide nonanatomic wedge excision is sufficient to obtain an adequate margin, although occasionally a lobectomy or segmentectomy is required (Fig. 135-2). Alternatively, the tumor may involve the pericardium or more likely the diaphragm. Pericardial reconstruction is necessary for right-sided resections, whereas wide opening of the entire pericardium on the left will suffice. The diaphragm is reconstructed with polytetrafluoroethylene with interrupted 0 Ethibond or Prolene sutures. This reconstruction is commonly performed independent of the chest wall reconstruction, but if the tumor involves portions of the ribs at the insertion site of the diaphragm, that edge of the Gore-Tex (W. L. Gore and Associates, TX, Flagstaff, AZ) will need to be incorporated into the resulting chest wall reconstruction as well.

The extent of chest wall resection typically includes one normal rib above and below the tumor. If an adequate chest wall margin cannot be obtained secondary to proximity to a vital structure, clips should be placed to guide adjuvant radiation therapy. Once the tumor is removed, the specimen should be inspected, and any questionable soft tissue margins should be marked and submitted for frozen-section analysis. A small Blake drain or chest tube should be placed into the pleural cavity through a separate incision.

Skeletal Reconstruction

Attention now turns to the first phase of chest wall reconstruction—the skeletal reconstruction. The choice of prosthetic material should be appropriately rigid, inert, malleable, and if possible, radiolucent to permit follow-up radiographic assessment.¹¹ Several prosthetic materials are available for reconstruction, including Marlex or Prolene mesh, polytetrafluoroethylene (2-mm thick), and methyl methacrylate placed between two pieces of Marlex mesh. The choice of material depends on the location of the defect, its size, as well as surgeon preference and experience.¹² We prefer to use the Marlex mesh-methyl methacrylate composite for large defects involving the sternum or anterolateral chest wall, where protection of the underlying cardiovascular structures is most important. The surgeon needs to fashion the methyl methacrylate to fit the defect and the contour of the chest wall and then exhibit all due patience as the substance hardens via an exothermic reaction. For smaller defects, DualMesh polytetrafluoroethylene is quite easy to use and is impervious to fluid and air. Regardless of the prosthetic material chosen, the prosthesis is sewn to the ribs with interrupted nonabsorbable sutures (0 Ethibond or Prolene) placed around the ribs superiorly and inferiorly and through holes drilled into the rib edges laterally and medially. An alternative to placing the sutures around the ribs and their associated neurovascular bundles is to drill holes in the ribs superiorly and inferiorly and place the sutures accordingly (Fig. 135-3). The prosthetic material is then secured in place with a slight amount of tension to confer some rigidity to the chest wall reconstruction (Fig. 135-4).

Occasionally the chest wall defect is very large and the number and length of resected ribs required to remove the tumor and have negative margins are significant. These large defects can be addressed through a combined prosthetic (titanium) rib osteosynthesis and expanded polytetrafluoroethylene (DualMesh).¹³ When this approach is used one needs to tailor the DualMesh such that its circumference is approximately 2 cm greater than the defect area. The number of titanium plates that should be used depends on the number of resected ribs, but in general one plate is sufficient for skeletal reconstruction of 2.75 ribs. While uncommon, there can be occasion to need a vertical expandable titanium prosthesis, and these devices are also available. Once the extensive skeletal chest wall defect is reconstructed, one should use a muscle flap to provide additional soft tissue coverage over the combined DualMesh and titanium plate reconstruction.

Chest wall defects that do not require skeletal reconstruction typically are very small (<3 cm) or posterior defects that lie above the fourth rib and are covered by the scapula. One does need to be aware that herniation of the scapular tip into the pleural cavity through an unclosed defect in the fifth or, less commonly, sixth rib can happen and is quite painful. These ultimately will require surgical reintervention.

Soft Tissue Reconstruction

After the skeletal reconstruction is completed, the second phase of chest wall reconstruction begins with mobilization and rotation of the muscle flaps or omentum to provide soft tissue coverage of the defect. This part of the procedure is often performed in conjunction with a plastic surgeon, although for smaller flaps and omentum we have performed the soft tissue coverage ourselves. We typically place Jackson–Pratt drains under the flaps, the harvest sites, or both to help prevent the formation of seromas.

The postoperative care of the patient who undergoes a chest wall resection and reconstruction centers on adequate pain control, pulmonary hygiene, and assessment of flap integrity and viability. Epidural analgesia combined with nonsteroidal medications typically provides adequate pain control. At the time of hospital discharge, we favor a long-acting nonsteroidal narcotic (e.g., OxyContin or MS Contin) to manage the patient's pain. Common to other major thoracic procedures, early patient mobilization, coughing, incentive spirometry, and respiratory treatments are instituted to avoid atelectasis and its attendant sequelae.

The viability and integrity of the flaps used to provide soft tissue coverage for the chest wall closure need to be assessed frequently. It is typical to observe some slight tissue swelling as well as some faint duskiness at the edges of a flap that has been maximally rotated. This needs to be watched carefully and, in conjunction with plastic surgery, debrided only when there is complete demarcation. Previously placed drains are removed when drainage is less than 30 mL per day or if there is any sign of infection at the drain site.

The most dreaded complication of chest wall resection and reconstruction of the skeletal defect is infection of the prosthetic material. This can occur with any prosthetic material but may be observed more frequently with Marlex or Prolene mesh constructs. In addition, it is much more likely to occur in patients with wounds that are contaminated preoperatively. Once infected, the mesh must be removed to completely eradicate the problem. Deschamps et al.¹⁴ report a 4.6% infection rate in 197 patients undergoing chest wall resection and reconstruction with prosthetic material. Fifty percent of those infected had mesh, and the others had polytetrafluoroethylene. Of note, the mesh was removed in all patients, and the polytetrafluoroethylene was removed in none. Even if the mesh requires removal, the lung commonly adheres to the chest wall, and thus an open pneumothorax is avoided. The wound is managed subsequently with debridement and gauze packing, and healing occurs by secondary intent.

Resection and reconstruction of the chest wall require a multidisciplinary effort. Optimal results are obtained with aggressive resection of tumor with adequate margins, followed by reconstruction of resulting skeletal and soft tissue defects. Complications are few, although prosthetic graft infection can be a challenging problem.

A 62-year-old man had resection of a right anterior chest wall malignant fibrous histiocytoma followed by adjuvant external beam radiation for positive margins. The initial resection included soft tissue only, and no ribs were resected. Two years later he presented with a painful recurrent mass (Fig. 135-5). He had no other complaints, and his performance status was good. CT scan demonstrated a large tumor involving the right anterolateral ribs with possible invasion of the diaphragm and lung (Fig. 135-6). A core needle biopsy of the lesion confirmed recurrent malignant fibrous histiocytoma.

The patient was scheduled for a combined thoracic and plastic surgery chest wall resection and reconstruction. After intubation with a double-lumen endotracheal tube, a wide local chest wall excision of the mass was performed, including all previously irradiated skin and soft tissue. The resection included removal of one noninvolved rib above and below the tumor (Fig. 135-7). The tumor was found at surgery to be invading the lung and diaphragm. A nonanatomic wedge resection of the right lower lobe was performed, and the diaphragm was resected en bloc with the tumor. The diaphragm then was reconstructed with polytetrafluoroethylene. Given the size of the chest wall defect, a methyl methacrylate mesh prosthesis was constructed and used to close the skeletal defect (Fig. 135-8). The resulting soft tissue defect was closed in conjunction with the plastic surgery service using a right transverse myocutaneous rectus abdominis flap. Jackson–Pratt drains were placed at the flap harvest site.

Although rare, the resection of chest wall tumors and subsequent “pearls” of reconstruction are critically important skills for all thoracic surgeons to master. Failure in either aspect often will significantly impact patient outcome and/or quality of life.