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.
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.
After exposing the primary chest wall tumor, rib shears are used to begin the chest wall resection 4 to 5 cm away from the primary malignant tumor.
The lung parenchyma may be adherent to the primary chest wall tumor. As shown here, this can be taken en bloc with the specimen with the aid of an endo-GIA stapler.
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.
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).
A pneumatic drill is used to place holes through the ribs for future placement of sutures, which are required to secure the prosthetic material used for the chest wall reconstruction.
The prosthetic chest wall material is secured to the underlying ribs with nonabsorbable suture. A second running layer between the prosthetic material and the intercostal muscles typically is used to help buttress the repair.
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.