With any major surgical procedure, one must perform careful assessment of preoperative status to reduce postoperative risks. Accurate assessment of patient’s nutritional status, coagulation profile, hemoglobin level, renal function, and hepatic function can provide better understanding of patient’s status. In addition to basic factors, it is crucial that patient undergoes the pulmonary and cardiovascular assessment prior to any surgical resection.
The most important presurgical evaluation for lung cancer patients is the pulmonary function test. If the forced expiratory volume in 1 s (FEV1) and carbon monoxide diffusion capacity (DLCO) are greater than 80 percent of the predicted values, the patient can tolerate up to a pneumonectomy. However, if the FEV1 and DLCO are below the 80 percent threshold, then the predicted postoperative value of lung function should be assessed by counting the number of segment remaining after removal of the tumor. The right upper lobe has three segments, the right middle lobe has two segments, the right lower lobe has five segments, the left upper lobe has four segments, and the left lower lobe has four segments. For example, if left lower lobectomy is planned then 14 segments (18 segments − 4 segments) or 77.8 percent (14/18) of the lung will be still available postoperatively. For a patient with a preoperative FEV1 of 60 percent, the postoperative predicted value would be 77.8 percent of 60 percent or 47 percent FEV1.48
For patients with obstructing tumors resulting in segmental/lobar/or pneumonic collapse, this estimate is no longer adequate since the segments that will be removed are no longer contributing effectively to the patient’s overall pulmonary function. A similar situation is seen when resecting lung that is significantly damaged secondary to emphysema. For these patients, measuring the percentage of perfusion and ventilation in the part of the lung to be resected provides a more accurate measure of postoperative lung function. For example, if a tumor involves the distal left lower lobe, bronchus, and pulmonary artery in a patient with an FEV1 of 45 percent, and the perfusion rate is only 5 percent in that lobe, the patient will have an FEV1 of 43 percent after resection or 95 percent of 45 percent.
The usual thresholds above which the planned resection can be performed without a significant increase in perioperative mortality is a postoperative predicted FEV1 and DLCO of 40 percent. When the postoperative predicted values are just above or below 40 percent patients should undergo cardiopulmonary exercise testing to determine whether surgery is appropriate. Patients with a maximal oxygen consumption (Vo2 max) of >15 mL/kg/min are not at an increased risk of complication or death following resection. However, patients with a Vo2 max of <10 mL/kg/min are at a significantly higher risk of complications or death and are not surgical candidates. Patients with a Vo2 max of between 10 and 15 mL/kg/min should undergo pulmonary rehabilitation. Pulmonary function should be reassessed periodically to determine whether these patients are candidates for pulmonary resection.
One exception to this rule is the patients with emphysema. Patients with poor pulmonary function and heterogeneous emphysema with upper-lobe predominance who develop a tumor in the upper-lobe may benefit from lung volume reduction surgery (LVRS) along with the resection of the lung cancer. The criteria for patients who can tolerate LVRS are an FEV1 of <40 percent, a DLCO >20 percent, total lung capacity >120 percent, and residual lung volume >150 percent.49 Rigorous pulmonary rehabilitation is necessary in patients who are going to undergo LVRS.
Patients must have adequate cardiac function to tolerate pulmonary resection. Cardiac work-up including an EKG, a detailed history, and an echocardiogram or a stress test, when indicated, should be performed to ensure that patients can tolerate lung resection. Coronary artery disease is cardiac significant risk factor for myocardial infarction following lung resection. The likelihood of myocardial infarction following resection in patients without coronary artery disease is <0.5 percent, while the likelihood of myocardial infarction following resection in patients with coronary artery disease is about 6 percent.50
Arrhythmias are also very common postoperatively and any preexisting arrhythmias will place patients at an even higher risk.
Although posterior lateral thoracotomy with entry through the fifth intercostal space remains the standard incision for anatomic pulmonary resections, complete resections can also be performed through posterior muscle-sparring, anterior muscle-sparing and axillary thoracotomies as well as VATS using two, three, or four incisions. The main advantages of VATS over traditional thoracotomy are reduced postoperative pain, earlier return to normal activity, and an increased likelihood of patients receiving adjuvant chemotherapy.
Upon entry into the thoracic cavity, the surgeon reassesses the clinical stage of the tumor. If there is pleural effusion that is positive for malignancy on cytologic evaluation or if the tumor is invading structures that cannot be resected, the surgeon aborts the surgery. The entire lung and parietal pleura are then inspected and palpated for additional masses. Any suspicious nodules located in lobes other than the tumor bearing lobe are biopsied and the specimens cytologically evaluated; if the nodules are positive for malignancy, the surgeon aborts the surgery. If there are malignant-appearing, broad-based, or dense adhesions to the chest wall the surgeon determines whether the tumor can be resected with negative margins. If the tumor is deemed resectable, the surgeon divides the inferior pulmonary ligament and renders the lung completely atelectatic.
The pulmonary vessels are now dissected along the plane of Leriche. This perivascular plane may be absent in the presence of long-standing granulomatous or tuberculous disease, after major chemotherapy or thoracic radiotherapy, and in cases of reoperation. In these situations, proximal control of the main pulmonary artery and the two pulmonary veins may be necessary before the more peripheral arterial dissection can be started. During an open operation the pulmonary arterial and venous branches can be ligated in any order. Although there is theoretical concern of pulmonary congestion when the pulmonary vein is ligated first, other collateral vessels between the lobes usually compensate adequately. During a VATS lobectomy the order in which vessels are ligated is more defined with the pulmonary vein often taken first.
Bronchial exposure should not involve stripping the bronchial surface of its adventitia. Aggressive dissection may compromise the vascular supply of the bronchus and lead to impaired healing and bronchial dehiscence. Overlying nodal tissues should be cleared, and major bronchial arteries should be clipped just proximal to the point of division. Bronchial closure has been greatly facilitated by the use of automatic staplers. With the stapler applied but not yet fired, the remaining lung should be ventilated to determine whether there is any impairment of ventilation secondary to stapler placement too close to a proximal lobar bronchus. Only when the absence of ventilatory impairment has been confirmed should the stapler be fired. When bronchial length is limited, the surgeon may perform suture closure of the bronchial stump rather than attempting to force a stapler around the bronchus. A vascularized rotational tissue flap should be used to reinforce the bronchial closure whenever there is a high risk of bronchial stump dehiscence such as in the presence of active infection, steroids, chemotherapy, radiation, or poor nutritional status.
First, the lung is then rotated posteriorly, and the pleura is incised posterior to the course of the phrenic nerve, which usually passes close to the base of the superior pulmonary vein. The phrenic nerve is carefully and gently mobilized anteriorly to expose the superior pulmonary vein and inferior pulmonary vein. Next, the right upper lobe is then rotated more inferiorly to provide a better view of the superior aspect of the hilum and allow complete exposure of the truncus anterior branch. Finally, the lung is rotated anteriorly, and the right main bronchus, right upper-lobe bronchus, and right bronchus intermedius are exposed.
After hilar dissection, the lung is rotated inferiorly and posteriorly, and the main trunk of the right pulmonary artery is exposed as it exits the pericardium posterior to the vena cava. The ligation and division of the right pulmonary artery can be accomplished using a vascular stapler or dividing the vessel between clamps and oversewing with 3-0 nonabsorbable sutures. Next, the lung is rotated posteriorly, and the superior pulmonary vein is mobilized on its superior and inferior aspects with blunt and sharp dissection then encircled, ligated, and divided using a vascular stapler. Division between clamps and oversewing with 3-0 nonabsorbable sutures is also acceptable. The lung is then retracted superiorly, and the inferior pulmonary vein is dissected, ligated, and divided in the same manner as the superior pulmonary vein.
After dividing the major vessels, the lung is retracted anteriorly and the subcarinal lymph nodes are mobilized. The bronchial artery originates at the apex of the carina anteriorly and should be clipped. The remaining peribronchial tissues are then mobilized distally with blunt and sharp dissection so that the bronchus is exposed within 1 cm of the carina. A tick tissue stapler is oriented so as to approximate the anterior cartilaginous and posterior membranous walls and the bronchus is divided distal to the staple line. On the right side, the coverage of the pneumonectomy stump with viable tissue is preferred, especially if the patient has received or will receive chemotherapy and/or radiotherapy. The ideal tissue for coverage is either a rotated intercostal muscle flap harvested during entry into the chest or a pericardial fat pad rotational flap. The flap is secured with carefully placed 4-0 polypropylene sutures.
Two branches of the pulmonary artery—the truncus anterior and posterior ascending arteries—enter the right upper lobe. The truncus anterior is the first branch of the right main pulmonary artery and is typically a large branch that immediately bifurcates into two or three branches. Once the truncus anterior is exposed, it is either suture-ligated and divided or transected with a vascular stapler. The posterior ascending artery typically originates from the interlobar pulmonary artery opposite the right middle lobe branch. To expose the posterior ascending pulmonary artery, the interlobar fissure is dissected, and the pulmonary artery is exposed at the junction of the major and minor fissures. All the branches are dissected including the middle lobe, posterior ascending, superior segmental, and basilar segmental arteries. The posterior ascending artery is often partially obscured by a level 11 interlobar lymph node and the posterior segmental branch of the superior pulmonary vein, which traverses the fissure towards the superior pulmonary vein. If the exposure is adequate, the posterior ascending branch can be ligated and divided or stapled. If the exposure proves difficult completion of the fissure between the upper lobe and lower lobe can sometimes facilitate this exposure. This is facilitated by dividing the pleura in the posterior hilum along the lateral edge of the bronchus intermedius. A level 11 lymph node located between the right upper-lobe bronchus and the bronchus intermedius is then removed to allow exposure of the posterior ascending branch of the pulmonary artery. A right-angle clamp can be passed from the interlobar fissure between the superior segmental branch of the pulmonary artery and the posterior ascending pulmonary artery to the posterior hilar dissection. The fissure can then be completed with either a medium or thick tissue stapler.
Next, the superior pulmonary vein is dissected, and the upper- and middle-lobe branches are carefully identified. The branches draining the upper lobe are then ligated and divided or stapled. Attention is now turned to completion of the minor fissure. Dissection continues along the lateral surface of the pulmonary artery until the right middle-lobe artery is identified. A right-angle clamp can be passed from this location posteriorly to the interlobar dissection. The minor fissure is then completed through the serial application of thick tissue staplers.
The upper lobe is retracted superiorly and posteriorly, and the pulmonary artery is gently retracted anteriorly. The bronchus is circumferentially exposed to the right upper lobe, and all nodal tissue surrounding the right upper-lobe bronchus is swept distally so that it can be included with the specimen. Once an adequate length of the right upper-lobe bronchus is exposed, the lung is rotated anteriorly to allow visualization of the course of the bronchus intermedius. The right upper lobe bronchus is compressed within with a thick tissue stapler and the right lung is ventilated to confirm that the bronchus intermedius has not been compromised. Once confirmed, the stapler is fired and the bronchus is divided distally.
The initial steps in a right middle lobectomy can begin with the interlobar dissection described above. There can be one dominant or two smaller middle-lobe arteries. Once the anatomy has been confirmed, the arterial branches to the middle lobe can be individually ligated and divided. If additional exposure is needed before ligation, the minor fissure can be completed to yield added exposure of a proximal middle-lobe artery. Once the arteries are divided, the lung is rotated posteriorly to expose the superior pulmonary vein. The branches to the upper and middle lobes are carefully identified, and the branches to the middle lobe are ligated and divided. The minor fissure is completed as described above. Once complete, the surgeon will have a clear view of the posterior segmental branch of the superior pulmonary vein and the interlobar pulmonary artery coursing posterior and medial to the veins. The fissure between the right middle and lower lobe can be completed using serial application of the thick tissue staplers by keeping the right middle lobe bronchus superiorly and the right lower lobe with the basilar branches of the pulmonary artery and the right lower-lobe bronchus inferiorly.
The middle lobe is then rotated superiorly and posteriorly to expose the right middle-lobe bronchus, which usually arises anterior and inferior to the right middle-lobe branches of the pulmonary artery. The basilar arterial branches to the right lower lobe are gently mobilized posteriorly to expose the bronchus intermedius and the origin of the right middle-lobe bronchus. Peribronchial lymph nodes located in this region should be dissected and removed, with care taken not to injure the bronchial arterial branches. Once the bronchus is free, it is divided and either oversewn or stapled.
Once again, the interlobar pulmonary artery and its branches are exposed in the major fissure. The pulmonary branches to the superior segment and the basilar segments of the right lower lobe, posterior ascending branch of right upper lobe, and right middle lobe branches are identified. The superior segmental and basilar segmental artery is encircled, ligated, and divided. Next, the fissure between the lower lobe and upper lobe is completed as described above for a right upper lobectomy. Next, the inferior pulmonary vein is then encircled as it exits the pericardium. This step is facilitated by the dissection of the superior edge of the inferior pulmonary vein with the lung rotated first anteriorly and then posteriorly. Once encircled, the pulmonary vein is divided with a vascular stapler. Then, the basilar segmental bronchi and the middle-lobe bronchus are exposed allowing division of the fissure between middle lower lobes. The removal of lymphoid tissue facilitates the application of stapler.
Level 11 and 12 lymph nodes are cleared distally along the bronchi to expose the origin of the superior segmental bronchus. The lung is then rotated anteriorly, and the bronchus intermedius is dissected distally until the origin of the superior segmental bronchus is identified. The branch of the inferior pulmonary vein draining the superior segment of the right lower lobe should be mobilized distally to allow adequate exposure of the origin of the superior segmental bronchus. The superior segmental bronchus is encircled, divided, and oversewn or stapled. Next, the basilar segmental bronchi are encircled at a point where closure will not affect airflow to the middle-lobe bronchus. Appropriate placement is confirmed by ventilating the right lung while the stapler or clamp is applied to the base of the basilar bronchi. If placement is adequate, the basilar segmental bronchi are divided and sewn or stapled.
Retract the lung anteriorly and open the hilar pleura to expose the inferior pulmonary vein, and continue superiorly to expose the left main bronchus and the pulmonary artery. Next, with the lung retracted inferiorly, the pleura is incised under the arch of the aorta to expose the left main pulmonary artery. A variable number of small vessels and vagal branches to the lung are encountered and can be ligated and divided. Care is taken not to injure the recurrent laryngeal nerve as it branches from the vagus nerve and courses under the arch just posterior to the ligamentum arteriosum. With the lung now retracted posteriorly, the hilar pleura is opened parallel to and posterior to the course of the phrenic nerve, exposing the main trunk of the left pulmonary artery and the superior pulmonary vein.
The superior and posterior surfaces of the main trunk of the pulmonary artery are dissected as it enters the thorax under the aortic arch. Once the perivascular space is entered, the entire vessel can be encircled with blunt dissection. If the superior pulmonary vein limits access to the anterior surface of the pulmonary artery, it may be ligated and divided first to facilitate arterial exposure. Once the pulmonary artery is encircled, the vessel can be divided using vascular stapler or between clamps.
Next, with the lung retracted posteriorly, the superior pulmonary vein is identified, encircled with blunt dissection, and then ligated and divided. The lung is then retracted superiorly to expose the inferior pulmonary vein. Dissection is performed on the anterior and posterior aspects of the inferior pulmonary vein, and blunt dissection is used to completely encircle the vein after which it is ligated and divided. Finally, the lung is retracted anteriorly and superiorly. Complete dissection of the subcarinal lymph nodes is performed and facilitated by dividing one or two pulmonary branches of the left vagus nerve and both bronchial arteries. Gentle traction in conjunction with blunt dissection is applied to allow encirclement of the proximal left mainstem bronchus. An effort should be made to encircle the bronchus within 1 cm of the carina. A thick tissue stapler is then passed around the left main stem bronchus and applied within 1 cm of the carina. If the patient has a left-sided double-lumen tube, ensure that it is pulled back proximal to the carina. The stapler is fired, and the bronchus is divided distal to the staple line. Frequently, the position of the bronchial stump under the aortic arch deep within the mediastinum renders coverage of the stump unnecessary.
The interlobar fissure is developed with a combination of sharp and electrocautery dissection. The posterior aspect of the fissure between the apicoposterior segment of the left upper lobe and the superior segment of the left lower lobe is completed with cautery or GIA stapler to expose the proximal portion of the interlobar pulmonary artery. The left upper lobe is then retracted anteriorly and superiorly to expose the arterial branches supplying the upper lobe. This anatomy varies among patients. Although there are usually three branches—the apico-anterior, posterior, and lingular pulmonary arteries to the left upper lobe—there may be as many as seven vessels. Each vessel should be identified and individually ligated and divided. Although the superior and posterior branches are easily dissected, the anterior-most branch is frequently obscured by an apical branch of the superior pulmonary vein. Division of this venous branch may improve exposure and facilitate control of the arterial branch.
The superior pulmonary vein can then be easily identified in the anterior hilum. If the apical branch was not previously ligated, the surgeon should make every effort not to damage the pulmonary artery branches that lie posterior to this portion of the vein. The majority of the superior pulmonary vein lies anterior to the left upper-lobe bronchus. Once this vein is encircled, it is ligated and divided. The fissure between the lingula and the lower lobe is now completed with serial application of tissue staplers. The left upper-lobe bronchus is encircled and either clamped or ligated with a thick tissue stapler. To prevent inadvertent injury, the pulmonary artery branches to the lower lobe should be gently retracted posteriorly during stapler placement. With the stapler clamped, the left lung is ventilated to verify that air is flowing freely to the entire left lower lobe, and the left-sided double-lumen tube is moved to ensure that the tube is not in the stapler. The stapler is then fired, and the bronchus is divided distal to the staple line.
Dissection begins again within the interlobar fissure. The pulmonary artery is identified, and the branches to the upper and lower lobes are dissected. The superior segmental artery is encircled, ligated, and divided. The basilar segmental arteries are then encircled distal to the origin of the lingular artery and ligated and divided, with care taken to preserve blood flow to the lingular artery. The anterior and posterior fissures are identified and divided with tissue stapler. The lung is rotated superiorly to expose the inferior pulmonary vein. Once the vein is encircled, it is ligated and divided. Attention is then redirected to the interlobar fissure, and the left lower-lobe bronchus is identified. The origin of the bronchus is cleared by dissecting nodal tissue distally with blunt and sharp dissection. The upper-lobe branches of the pulmonary artery are gently retracted superiorly to allow placement of a tick tissue stapler on the bronchus. With the stapler clamped, the anesthesiologist ventilates the left lung to confirm the adequacy of airflow to the upper lobe, and that the stapler is not entrapping the double-lumen tube. The stapler is fired and the bronchus is divided distal to the staple line.
A chest tube is placed after surgical resection to prevent symptomatic pleural effusion. The amount of pleural fluid output over a 24-h period that is considered safe to allow removal of the tubes has long been debated. However, a single-institution retrospective series recently found that symptomatic pleural effusion occurred after chest tube removal in just 11 of 2077 patients (0.55%) who had their chest tube removed for <450 mL of nonchylous drainage per day.51
Persistent air leak is defined as an air leak that occurs for at least 5 days following surgery. The incidence of persistent air leak is about 10 percent for patients who are undergoing lobectomy based on the Society of Thoracic Surgery general thoracic surgery database that looked at 4979 cases.52 A significantly smaller incidence of air leak of 3.2 percent was reported in a single-institution retrospective series when patients undergoing segmentectomy or wedge resections were mixed with lobectomy patients. In that series, the patients with a persistent air leak whose lung remained expanded off suction were discharged with their chest tube in place. At follow-up on an average of 16 days later, 57 of the 199 patients (28%) had persistent air leak and/or pneumothorax. All patients’ chest tubes were eventually removed during follow-up. Over the next 3 months, air leaks resolved in all but three patients, who developed empyema.53
About 10 percent of patients develop pneumonia after undergoing pulmonary resection. Pneumonia carries a mortality rate of 19 to 26 percent following lung resection.54,55 For patients who are undergoing pneumonectomy, pneumonia-associated mortality rates are 40 percent and smoking within 1 month of the operation increases the risk of developing pneumonia nearly threefold.56 Pneumonia usually develops 2 to 4 days after surgery. Bronchial colonization, male gender, and chronic obstructive pulmonary disease are independent predictors of postoperative pneumonia. Standard treatments used to prevent pneumonia after lung resection includes prophylactic antibiotics, chest physiotherapy to clear secretions, bronchodilator placement, effective pain control, and early ambulation. The standard treatment for postoperative pneumonia is broad-spectrum antibiotics followed by targeted antibiotics selected on the basis of culture results. Repeated bronchoscopies can also be used to facilitate clearance of secretions
Atrial fibrillation is a common complication following pulmonary resection. The incidence of supraventricular arrhythmias following pulmonary resection is 10 to 28 percent. Although the cause of atrial fibrillation is unclear, contributing factors may include postoperative inflammation, right heart strain owing to right ventricular dilatation, pulmonary hypertension, and/or increased right heart pressures. Alternative explanations include conduction abnormalities from ligation of the pulmonary veins that contain the atrial fibers. The incidence of postoperative atrial fibrillation increases with the amount of lung tissue resected. Patients who undergo pneumonectomy are at the higher risk of developing atrial fibrillation. Curtis et al. found that postoperative supraventricular arrhythmias developed in 46.1 percent of patients who underwent pneumonectomy but only 14.3 percent of patients who underwent lobectomy.57 Age is the second most important risk factor associated with development of atrial fibrillation. In addition to amount of lung resected and advancing age, male gender, history of congestive heart failure, and history of arrhythmias are risk factors for postoperative atrial fibrillation.58 Atrial fibrillation often occurs in the first 24 to 72 h following thoracotomy. Although patients who develop atrial fibrillation frequently have a higher incidence of other complication,59 the atrial fibrillation is usually controlled with medical therapy that is typically discontinued within 4 to 6 weeks of surgery.60
Empyema and Bronchopleural Fistula
Empyema occurs in 1 to 2 percent of patients after lobectomy and 2 to 12 percent of patients after pneumonectomy. The management of postoperative empyema depends on the timing of its onset, the stability of the patient, and the presence of a bronchopleural fistula. If a bronchopleural fistula develops within the first 2 days after resection, the best option may be an additional surgery that includes debridement of the stump, reclosure at the healthy bronchus, and placement of a muscle flap. The stump should be tested to ensure that no air leaks are present.
If empyema develops more than 2 days after resection, the initial treatment includes administering broad-spectrum antibiotics, draining the space with close-tube drainage, and using flexible bronchoscopy to determine whether a bronchopleural fistula is present. If the patient is medically unstable, Eloesser flap should be performed to provide the best way to sterilize the space. If the patient is stable, treatment depends on whether bronchopleural fistula is present. If bronchopleural fistula is not present, a modified Clagett procedure, in which antibiotic solution is instilled and then drained to sterilize the fluid, can be performed.61 However, if bronchopleural fistula is present, the treatment will vary based on the operative side, the size of the fistula, the availability of suitable muscle flaps, and a number of other factors. This discussion is beyond the scope of this chapter but muscle flap coverage of the fistula, and vascularized tissue placement to fill the postresectional, or even a thoracoplasty.