Evarts Graham performed the first successful pneumonectomy for lung cancer in 1933.1 Pulmonary resection was also applied to patients with tuberculosis before effective drugs were developed. Lobectomy became the standard procedure as a radical resection for lung cancer in the 1950s. Cahan described procedures of mediastinal and hilar lymph node dissection for pneumonectomy and lobectomy in 1951 and 1960. Bronchoplasty and arterioplasty were introduced to lung cancer surgery in the 1970s. Techniques for locally advanced lung cancer invading great vessels and/or the heart were described in the 1960s and were applied as clinical practice in the 1980s. Limited resection—that is, segmentectomy or partial resection of the lung—were examined as potential operations for lung cancer. However, the results of a randomized controlled trial revealed that local and/or regional recurrence occurred more frequently in the limited resection group than in the conventional lobectomy group and this translated into a survival difference. Video-assisted thoracoscopic surgery (VATS) lobectomy has been introduced as an option for early stage lung cancer and, in many centers, is the procedure of choice for a majority of pulmonary resections.
PRINCIPLES AND JUSTIFICATION
Right-sided pulmonary resections include pneumonectomy, lobectomy with or without bronchoplastic procedures, segmentectomy, and partial (wedge) resection. These procedures are common and applicable to lung malignancies, inflammatory lesions, and congenital anomalies. Most of the inflammatory diseases can be controlled pharmacologically, and lung cancer has become the most common reason to proceed with pulmonary resection. Bronchoplastic procedures are performed on the right side much more frequently than on the left because of asymmetric anatomy of the tracheobronchial tree and the pulmonary artery, specifically because of the position and angulation of the right upper lobe orifice in relation to the carina. That being said, bronchoplastic procedures on the left side are feasible but often involve resection and reconstruction of the pulmonary artery in order to preserve pulmonary parenchyma and avoid a pneumonectomy.
PREOPERATIVE ASSESSMENT AND PREPARATION
The size, extent, and location of the lesion are the most important factors in deciding what procedure to choose. Computerized tomography (CT) provides good information concerning the extent of the locoregional disease in addition to identifying the presence of distant metastatic disease. Thoracic CT images the primary tumor, nodal involvement, intrapulmonary metastases, and pleural involvement with or without effusion or pleural dissemination. Malignant effusion and intrapulmonary metastases, if seen on CT scan, render the patient inoperable and contraindicate curative resection of a lung cancer. A tissue diagnosis should be confirmed histologically or cytologically, either with a percutaneous needle aspiration biopsy or bronchoscopy. Upper mediastinal lymph node metastases can be documented histologically, either by mediastinoscopy or endobronchial ultrasound guided biopsy if the thoracic CT shows enlarged lymph nodes.
Smoking should cease at least 4 weeks prior to surgery to decrease bronchial secretion and to reduce the likelihood of postoperative pulmonary complications. This often is difficult for the patient who has been a long-term smoker. In
cases of an inflammatory lesion or a lung cancer with airway obstruction, secretions from the lesion and/or obstructed bronchi must be controlled during the operation. The facedown prone position prevents secretions from flowing into the opposite healthy lung. However, the face-down position limits the operative procedure. More commonly, operations are performed in the lateral decubitus position under anesthesia, with a separate ventilation tube to suction secretions during the operative procedure. Inhalation anesthesia stimulates the bronchial glands and increases secretion. Instead of inhalation anesthesia, intravenous anesthesia with epidural anesthesia is used in cases where significant secretions are expected. Epidural analgesia, instituted at the time of operation usually is continued until after the chest drain has been removed.
Incision and exploration
Pneumonectomy and lobectomy may be performed through a standard posterolateral thoracotomy. However, with recent advances including the introduction of VATS and the development of surgical instruments, skin incisions have become smaller than those formerly used for standard thoracotomy. Although some doctors recommend VATS lobectomy even for cases of lung cancer, open remains the most common procedure used to perform radical resection with systematic nodal dissection for lung cancer.
Exposure of the hilum
- Exposure of the hilum of the lung is the first step of pulmonary resection. The reflection of the mediastinal pleura is opened from anterior to posterior beyond the right main bronchus. In the case of lung cancer located in the hilum, intrapericardial division of pulmonary vessels may be required depending on the extent, or lack thereof, of hilar invasion. (See Figure 12.1).
In cases of lung cancer involving the main bronchus, right pulmonary artery, pulmonary veins, or left atrium, pneumonectomy has to be a consideration to achieve a curative resection, though an assessment should always be made as to whether a bronchoplastic procedure with or without a vascular resection might be feasible.
DISSECTION OF THE PULMONARY LIGAMENT
- In cases of lung cancer located in the lower or middle lobe, lower mediastinal lymph node dissection is required. After opening the pleura along with pulmonary ligament at the reflection, fatty tissue including lymph nodes is divided from the esophagus and the vagus nerve until the lower border of the inferior pulmonary vein is exposed. Retracting the lower lobe cephalad provides adequate exposure. (See Figure 12.2).
SUBCARINAL LYMPH NODE DISSECTION
- The subcarinal lymph node space is triangle shaped, with the nodes located posterior to the right pulmonary artery, left atrium, and both pulmonary veins. Therefore, early dissection of the subcarinal lymph node improves the exposure of the inferior pulmonary vein as well
as the mainstem bronchi. The dissection is begun by elevating the lymph node mass off the pericardium using clips on the many small vessels encountered during the dissection. The nodal mass may be grasped with ring forceps to provide counter traction. Clips should be used liberally. Vagal branches going toward the lung are clipped and divided. Ideally, the entire nodal mass is removed as a package, with clips placed to minimize bleeding. (See Figure 12.3).
DIVISION OF THE INFERIOR PULMONARY VEIN
- The inferior pulmonary vein is exposed after the inferior mediastinal and subcarinal lymph node dissection has been completed. The vein should be encircled and the adventitia of the vein exposed to perform complete lymph node dissection and to confirm the reflection
- If the incision line crosses the pericardium, the pulmonary veins and artery should be divided within the pericardium (see Figure 12.5).
DIVISION OF THE SUPERIOR PULMONARY VEIN
The superior pulmonary vein will be easily exposed by incising the overlying pleura. When encircling the vein, care must be taken to avoid injury to the pulmonary artery, which lies immediately behind the vein. The soft tissue and lymph nodes located in front of the superior vein should be dissected until the anterior adventitia of the vein is completely exposed. If dissection of the vein is performed in the subadventitial plane the possibility of injury to the adjacent pulmonary artery will be minimized. Recently, the superior pulmonary vein has almost always been divided with a stapler. However, in the case of a tumor invading or located in the hilum, either a suture or suture ligation technique may be used (See Figure 12.6).
DIVISION OF THE RIGHT PULMONARY ARTERY
The right pulmonary artery and superior vena cava are connected by a fibrous membrane at the bifurcation of the upper and lower branches of the pulmonary artery. This membrane is a part of the pericardium. Division of this membrane makes central dissection of the anterior aspect of the right pulmonary artery easy. As the posterior wall of the right pulmonary artery is covered by a fibrous portion of the pericardium attaching the trachea and both main bronchi, this fibrous portion should be divided from the bronchus to expose the artery completely. This is particularly important for very proximal lesions where safe division of the artery requires obtaining adequate length. The safest move to execute division of the pulmonary artery employs the use of a vascular stapler. When the stapler is used to divide the pulmonary artery, ideally a vascular clamp should be placed, in case of the very rare occurrence of the stapler cutting without laying down staples. After the artery is cut, the central stump should be dissected from neighboring structures to render the stump free from tension to avoid tearing near the staples. (See Figure 12.7 a and b).
MEDIASTINAL LYMPH NODE DISSECTION
To expose the superior mediastinum, the mediastinal pleura is opened longitudinally from the azygos vein to the apex of the thorax and horizontally at the apex. The
azygos vein may be divided to facilitate the dissection, especially if lymph nodes are enlarged secondary to the tumor, but rarely is this necessary. The entire contents of the space bordered by the trachea posteriorly, the superior vena cava anteriorly, the right subclavian artery superiorly, and the azygous vein inferiorly should be removed with the liberal use of hemoclips and electrocautery. The dissection may be facilitated by grasping the nodal mass with ring forceps. The subcarinal space is then entered and the lymph nodes removed, taking care to clip any bronchial arterial branches. (See Figure 12.8).