Overview of pulmonary resection

INTRODUCTION — Pulmonary (lung) resection is used for the treatment of pulmonary malignancy, infection, and trauma. In addition, pulmonary resection can be used as a means to diagnose pulmonary disease.

An overview of lung resection, including the types of resection, a comparison of open and minimally invasive techniques, and complications, is reviewed here. Specific management of pathologies that indicate a need for lung resection and disease-specific outcomes related to lung resection are discussed in links provided below. Additional detail regarding minimally invasive thoracoscopic surgery is provided separately. (See "Overview of minimally invasive thoracic surgery".)

LUNG ANATOMY AND TYPES OF LUNG RESECTION — Below is a summary of the modes of lung resection. The various lung resections are broadly regarded as anatomic or non-anatomic resections. The extent of resection is based upon the size, location, and type of lesion found within the lung. In addition, the ability to obtain a negative margin is an important consideration in determining the choice of resection, which varies based on pulmonary pathology requiring resection.

Anatomy and bronchopulmonary segments — The right and left lungs are contained within the thorax and separated by the mediastinum (containing the heart). Each lung is divided into lobes, with each lobe having its own bronchial, arterial, and venous supply. Lobes are further divided into bronchopulmonary segments (figure 1), which also have their own segmental bronchial and vascular supply. The lobar and segmental anatomy are the basis for surgical resection of the lung.

The right lung has three lobes (upper, middle, and lower) and 10 segments. The left lung is slightly smaller than the right as it must accommodate the heart. The left lung has two lobes (upper and lower) and eight segments. The left upper lobe can be further divided into named divisions, each with its own vascular and bronchial supply, the superior division and the lingular division. The superior division is anatomically similar to the right-sided upper lobe while the lingular division is comparable to the right middle lobe. The oblique fissure on each side divides lower lobes from the remainder of the lung, namely the upper lobe on the left and both the upper and middle lobes on the right. The horizontal fissure is located in the right lung only and divides the upper and middle lobes.

The lung requires adequate ventilation and perfusion for gas exchange. Ventilation refers to the movement of air into and out of the lungs, and perfusion is the amount of pulmonary blood flow through the lung. The amount of ventilation and perfusion varies between the different lobes of the lung due to gravity and pressure variances between the alveolar, arterial, and venous systems. The right lung typically provides about 55 percent of total ventilation and perfusion, with the right upper lobe providing approximately 20 percent, right middle lobe approximately 10 percent, and right lower lobe approximately 25 percent. The left lung provides about 45 percent of total ventilation and perfusion, with the left upper and lower each providing 22.5 percent.

Anatomic resection — An anatomic resection requires ligation and division of the feeding vessels and airways to a segment or lobe of the lung (figure 1). (See 'Anatomy and bronchopulmonary segments' above.)

The pulmonary artery is a fragile vessel and thus requires careful dissection and handling. Undue tension or grasping of the artery may lead to intimal disruption or tearing of the vessel leading to significant hemorrhage. The pulmonary vein, although more robust, also requires delicate handling.

Ligation and division of the pulmonary vessels is achieved in a variety of ways, including triple ligation with silk ties, ligation with clips, ties and suture ligature, or mechanical stapling. Ultrasonic energy devices have been shown to be effective for the ligation and division of vessels up to 6 mm [1,2]. The bronchus is most commonly ligated with a stapler; a linear cutting stapler allows for both ligation and division of the bronchus with a single firing of the device. Alternatively, the bronchus may be sharply divided and closed with suture.

Surgical linear cutting staplers are used to divide the lung parenchyma, providing fast and reliable hemostasis of the cut edge of remaining lung, thus minimizing air leak.

Pneumonectomy — Right pneumonectomy removes the entirety of the right lung (upper, middle, and lower lobes), whereas a left pneumonectomy removes the entirety of the left lung (upper and lower lobes).

Lobectomy — Lobectomy (anatomic lobar resection) removes the individual lobe by ligating its contributing pulmonary arteries, egressing pulmonary veins and lobar bronchi.

Segmentectomy — A segmentectomy (anatomic sublobar resection) removes one or more segments by dividing their contributing arterial, venous, and bronchial elements. This procedure is often reserved for treating tumors smaller than 2 cm that are well within a segment; patients who cannot tolerate larger pulmonary resection (eg, lobectomy) due to marginal pulmonary function tests and other comorbidities; or to treat low-grade malignancies such as typical carcinoids; and metastases. A study in 1995 by the Lung Cancer Study Group suggested that sublobar resection was inferior to lobectomy (tumor size <3 cm), reporting an increase in recurrence and trend toward decreased survival in patients undergoing sublobar resection. However, later studies, CALGB 140503 and JCOG0802, display noninferiority with respect to survival in patients with tumors sized 2 cm or less, leading to increased acceptance of this approach in stage IA lung cancer patients [3,4].

Sleeve resection — A sleeve resection is an alternative to a pneumonectomy. This procedure conserves lung tissue by removing a lobe containing a target lesion with a portion of the lobar bronchus to an uninvolved lobe. The remaining bronchus to the uninvolved lobe is anastomosed to the remaining proximal airway.

Nonanatomic wedge resection — A wedge resection is the non-anatomic removal of a portion of the lung, meaning the contributing vessels and minor airways are not individually dissected and ligated. Lung wedge resections are akin to removing a pie slice with the portion of excised lung encompassing a lesion or area of disease/abnormality (figure 2). Pulmonary wedge resection is often chosen for obtaining tissue for diagnostic purposes and to definitively resect peripheral lesions.

Wedge resections may be completed via open thoracotomy or minimally invasive techniques. If the lesion is small or not visible on the surface of the lung, digital palpation may be necessary to localize the lesion. When using minimally invasive techniques (movie 1), instruments or a finger may be inserted into the chest cavity to palpate the lung and localize the lesion.

Landmarks may also be used to estimate where the lesion is located, but some interpolation is necessary since radiologic imaging is usually performed with the lung fully inflated, while surgery is performed on the deflated lung. If it is anticipated that a nodule will be hard to find, it can be localized using a variety of methods, such as computed tomography (CT)-guided needle localization, dye marking, radionucleotide, and real-time on-table imaging [5-7].

Surgical linear cutting staplers are used to divide the lung parenchyma, providing fast and reliable hemostasis of the cut edge of remaining lung, thus minimizing air leak. Alternatively, lung parenchymal tissue can be divided between parallel clamps and oversewn with a running absorbable suture; this technique, however, results in a slightly higher rate of air leak.

INDICATIONS — Indications for pulmonary resection include malignant and benign conditions. In addition, although pulmonary injuries can often be managed conservatively, these may also require resection for management. (See "Pulmonary contusion in adults".)

Malignancy

Primary lung disease — Primary lung cancer is the leading cause of cancer-related death in males and females [8]. Smoking remains the number one risk factor for the development of lung cancer [9]. Other known environmental risk factors include radon and asbestos. In addition, host factors include family history of lung malignancy and chronic obstructive pulmonary disease (COPD).

Lung cancer is broadly categorized into two major groups: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). This designation is determined by tumor histology, with adenocarcinoma, a type of NSCLC, being the most common [10]. Cancer staging is in accordance with the tumor, node, metastasis (TNM) system (table 1). The lung cancer staging system is the cornerstone for the management of malignant lung disease. Resection is the primary treatment for stages I and II lung cancers in patients without contraindications to surgery. Stage III lung cancers, a heterogenous group with varying tumor size and nodal status, are more varied in their management; however, surgery may be an aspect of the treatment strategy. (See "Overview of the initial treatment and prognosis of lung cancer", section on 'Treatment'.)

Metastatic disease — The lung is the third most common site of extrapleural metastasis from other types of tumor, behind the lymph nodes and the liver [11]. The most common metastases to the lung are epithelial tumors (including colorectal, breast, urinary system), followed by sarcomas, germ cell tumors, and melanoma, respectively [12]. Of the epithelial tumors, colorectal cancers are the most frequent primary tumors to metastasize to the lung [13]. (See "Surgical resection of pulmonary metastases: Benefits, indications, preoperative evaluation, and techniques".)

In selected patients, resection of metastatic lesions is appropriate. Metastasectomy can be performed provided all of the following are satisfied:

●The primary tumor is controlled.

●The patient is medically fit and can tolerate resection.

●Lesion(s) are completely resectable.

●There are no extrapulmonary metastases. (If extrapulmonary metastases are present, these lesions can be controlled with surgery or an alternative modality.)

●Lack of availability of other effective treatment.

Lung metastasectomy is often completed with a lung-sparing technique such as wedge resection or anatomic segmentectomy, although lobectomy or even occasionally pneumonectomy may be indicated and required for centrally located tumors. A longer disease-free interval, smaller number of metastatic nodules, and ability to achieve a complete resection portend a favorable outcome. (See "Surgical resection of pulmonary metastases: Benefits, indications, preoperative evaluation, and techniques", section on 'Factors that may influence the decision'.)

Benign disease — Many benign lung resections are resected using tissue-sparing techniques (eg, partial lung resection, sublobar wedge resection, segmentectomy).

Pulmonary blebs and bullae — Resection of blebs and bullae (figure 3) may be indicated to prevent spontaneous pneumothorax from rupture or to manage air leak following thoracostomy tube placement (picture 1) [14]. (See "Pneumothorax in adults: Epidemiology and etiology" and "Bullectomy for giant bullae".)

Bullae, which are thinned areas of lung parenchyma, are typically >1 cm in diameter with wall thickness <1 mm and typically occur from parenchymal destruction such as that caused by emphysema, typically from smoking, but also from other causes, such as alpha-1 antitrypsin deficiency. Large bullae can occupy up to one-half of the volume of the pleural cavity, leading to contralateral lung compression (picture 2). A bleb is smaller than 1 cm in diameter and typically subpleural and located more cephalad. Blebs may occur from alveolar disruption in patients with otherwise relatively normal parenchyma.

When intervention is indicated, the margins of resection should be performed in the more normal (less emphysematous) lung parenchyma, which will decrease the risk of prolonged air leak that can occur due to poor sealing of thin lung parenchyma at the staple line margin or from lung lacerations that may occur from taking down adhesions. (See "Bullectomy for giant bullae".)

To prevent prolonged air leaks from stapled margin lines, bovine pericardial, bioabsorbable, and synthetic absorbable buttresses have been used [15]. In one randomized trial that included 80 participants, there was no significant difference in hospital stay or time to chest tube removal for patients randomly assigned to the buttress or standard stapled division; however, there was a trend toward shortened air leak time and chest tube duration [16].

Benign masses and nodules — Benign lung lesions are often diagnosed during the workup of an incidentally identified solitary pulmonary nodule or evaluation of concerning symptoms (eg, chronic cough, hemoptysis). Overall, the need to resect a benign lesion is rare. Most benign lesions such as pulmonary hamartoma, mucous gland adenoma, histiocytoma, and pulmonary lipoma do not require resection unless symptomatic. Others, such as mucinous cystadenoma and intrapulmonary fibrous tumors, require resection due to malignant potential or increased likelihood of becoming symptomatic in the future. Often these indeterminate lesions are identified following diagnostic resection. (See "Diagnostic evaluation of the incidental pulmonary nodule" and "Diagnostic approach to the adult with cystic lung disease".)

Bronchiectasis — Bronchiectasis is an obstructive lung disease identified by inflammation and dilation of the bronchi with destruction of the bronchial wall. Viral and bacterial infections are often the inciting event leading to initial airway damage, while fungal infections have also been responsible. Destruction of the bronchial wall leads to its collapse, and impaired sputum clearance leads to repeated respiratory infection or chronic sputum production. The sputum can be blood tinged, or the patient may present with hemoptysis. Surgical treatment may be indicated if medical therapies fail. The ideal candidate for surgical therapy has localized disease that is amenable to anatomic lung resection such as segmentectomy or lobectomy [17]. (See "Bronchiectasis in adults: Treatment of acute and recurrent exacerbations", section on 'Surgical resection, in localized bronchiectasis'.)

Infectious lung disease — Lung infections can be broadly categorized into bacterial, mycobacterial, and mycotic pleural infections. Most infectious diseases of the lung are treated medically, which is successful in nearly 90 percent of patients. Indications for surgery include persistence of disease in spite of optimal medical therapy, empyema, hemoptysis, and development of bronchopleural fistula [18]. (See "Lung abscess in adults", section on 'Surgical intervention' and "Mucormycosis (zygomycosis)", section on 'Surgery' and "Bronchopleural fistula in adults".)

Chronic obstructive pulmonary disease — In selected patients, emphysematous lung tissue may be removed, reducing the size of overinflated parenchyma, which allows the more functional lung tissue to expand. Resection is typically reserved for patients with severe and heterogeneous emphysema. The results of the National Emphysema Treatment Trial (NETT) identified a select group of patients who were the best candidates for lung volume reduction surgery (LVRS) [19]. Patients typically have upper lobe emphysema and low exercise capacity. These patients were more likely to live longer and function better after LVRS than after medical treatment [20]. (See "Lung volume reduction surgery in COPD".)

Traumatic injury — Pulmonary trauma is broadly separated into blunt and penetrating injuries. Injury can occur to the airway, pulmonary parenchyma, or pulmonary vasculature, or a combination of injuries can occur. Minor injuries can often be managed conservatively, but for more severe injuries, pulmonary resection may become necessary. Pulmonary parenchymal lacerations can often be treated with tube thoracostomy alone. If extensive tissue loss is present, a nonanatomic (wedge) resection or lobectomy may be required. In the acute setting, a thoracotomy is often necessary to provide adequate exposure for expedient repair. (See "Initial evaluation and management of blunt thoracic trauma in adults" and "Initial evaluation and management of penetrating thoracic trauma in adults".)

Tracheobronchial injuries are rare and are usually the result of high-energy blunt impact. These injuries often occur in the presence of multiple trauma presenting with respiratory distress and persistent air leak. Flexible bronchoscopy is diagnostic, and primary surgical repair is often required. When the injury to the bronchial tree is severe, lobectomy or pneumonectomy may be required [21]. (See "Identification and management of tracheobronchial injuries due to blunt or penetrating trauma".)

Pulmonary vascular injuries are typically due to penetrating trauma or from deceleration injury. The pulmonary vascular system is low pressure, such that with lung expansion, compression of smaller vessels will often stop the bleeding. If the bronchial arterial supply remains intact, lobar and segmental pulmonary arteries may be ligated. However, pulmonary venous injury that requires ligation will also require resection of the corresponding pulmonary parenchyma since pulmonary vein obstruction will result in pulmonary infarction. (See "Overview of blunt and penetrating thoracic vascular injury in adults".)

Pulmonary contusion, which is the most common pulmonary injury and can occur with either blunt or penetrating trauma, rarely requires surgical intervention [22]. (See "Pulmonary contusion in adults".)

PREOPERATIVE EVALUATION AND PREPARATION — The operating surgeon should evaluate the patient anatomically and medically to assess the risks of morbidity and mortality following pulmonary resection. This evaluation should begin with a focused history and physical examination and includes preoperative laboratory studies and pertinent imaging.

Depending upon the complexity of the operation, duration, and positioning, the type of anesthetic, monitoring, ventilation, and oxygenation parameters will vary. There should be clear communication between the surgeon and the anesthesiologist about the plan for the operation as well as the possible complications and their immediate treatments. (See "Anesthesia for open pulmonary resection" and "Anesthesia for video-assisted thoracoscopic surgery (VATS) for pulmonary resection" and "One lung ventilation: General principles" and "Lung isolation techniques".)

Pulmonary risk assessment — An overview of the evaluation of pulmonary risk is reviewed separately. (See "Evaluation of perioperative pulmonary risk" and "Preoperative physiologic pulmonary evaluation for lung resection".)

Coronavirus disease 2019 (COVID-19) increases the complexity of cancer care. Specific guidance for decision-making for cancer surgery on a disease-by-disease basis is available from the Society of Thoracic Surgeons, from the Society of Surgical Oncology, and from others. These and other recommendations for cancer care during active phases of the COVID-19 pandemic are discussed separately. (See "COVID-19: Perioperative risk assessment, preoperative screening and testing, and timing of surgery after infection" and "COVID-19: Considerations in patients with cancer".)

Pulmonary function testing — Preoperative pulmonary function testing is required prior to elective pulmonary resection. Pulmonary function tests (PFTs) include spirometry, lung volume measurements, and quantification of diffusing capacity. Forced expiratory volume in one second (FEV1) and diffusing capacity of the lung for carbon monoxide (DLCO) provide the best estimate of postoperative morbidity and mortality [23]. (See "Overview of minimally invasive thoracic surgery", section on 'Contraindications' and "Evaluation of perioperative pulmonary risk" and "One lung ventilation: General principles".)

In most emergent situations, a brief assessment based on history and patient functional status prior to illness is usually sufficient. The results of arterial blood gas may also be helpful when PFTs cannot not be obtained in an urgent situation.

Predicted postoperative values — Predicted postoperative values for diffusing capacity of carbon dioxide (ppo DLCO) and forced expiratory volume at one second (ppo FEV1) should be calculated (calculator 1 and calculator 2) in all patients considered for pulmonary resection. The calculation is based on the assumption that the various segments of the lung contribute equally to the patient's total lung function. By counting the number of resected segments, the remaining lung function is calculated. Patients with ppo DLCO or ppo FEV1 <40 percent are at moderate-to-high risk for postoperative morbidity. When patients do not meet the minimal ppo FEV1 and ppo DLCO, additional functional assessments, including cardiopulmonary exercise testing, stair climbing, six-minute walk test, and ventilation/perfusion scans may aid in determining eligibility for resection [24]. (See "Preoperative physiologic pulmonary evaluation for lung resection", section on 'Predicted postoperative pulmonary function'.)

Cardiac risk assessment — The goals of preoperative cardiac risk assessment are to identify patients with active cardiac disease and to initiate risk factor modification and management. Patients with active or high-risk cardiac conditions require preoperative correction or identification of alternative nonsurgical management strategies [25]. (See "Evaluation of cardiac risk prior to noncardiac surgery" and "Management of cardiac risk for noncardiac surgery".)

Preoperative lung imaging — Lung imaging studies (computed tomography [CT] of the chest, plain chest radiography) should be obtained (and repeated if necessary) within six to eight weeks of the planned thoracic surgery, particularly for inflammatory or infectious etiologies. For malignancy, imaging within 10 to 12 weeks is sufficient.

The CT protocol depends upon the nature of the pathology being evaluated for resection or repair. For resection of lung cancer, our preference is fusion CT/positron emission tomography (CT/PET), which improves the accuracy of clinical preoperative staging. (See "Overview of the initial evaluation, diagnosis, and staging of patients with suspected lung cancer", section on 'Whole-body FDG PET and PET/CT'.)

For patients with suspected invasion or involvement of vascular, neurologic, or bony structures that may change or preclude operative management, we obtain magnetic resonance (MR) imaging of the thorax.

Preventive measures

●Thromboprophylaxis – The risk of venous thromboembolism (VTE) in patients undergoing pulmonary resection depends upon the indication for surgery, extent of resection, and postoperative course. In a review of over 14,000 patients, the overall incidence of VTE was 1.6 percent [26]. Nearly half of VTE events occurred post-discharge. The incidence of VTE was significantly higher following pneumonectomy compared with lobectomy (2.0 versus 0.6 percent; odds ratio [OR] 3.4, 95% CI 2-6.0). The VTE incidence was also higher for open lung resection compared with minimally invasive resection and extended length of stay. Other factors included prolonged operative time, age, and obesity. Prophylactic measures to reduce the incidence of VTE are discussed separately. (See "Prevention of venous thromboembolic disease in adult nonorthopedic surgical patients".)

●Postoperative arrhythmia – The risk of atrial fibrillation and flutter following major lung resection ranges from 10 to 20 percent with higher rates among those undergoing pneumonectomy. Atrial fibrillation is the most common sustained postoperative arrhythmia. Postoperative arrhythmia is most likely to occur on days 2 to 4 and often resolves within four to six weeks of surgery. In a review of 4731 patients undergoing lobectomy or more major lung resections, risk factors for postoperative atrial fibrillation included transfusion, inotrope usage, open (rather than thoracoscopic) surgery, and history of excessive alcohol consumption [27]. In a systematic review that included 10 trials, pharmacologic prophylaxis significantly reduced the risk of postoperative atrial fibrillation (relative risk 0.53, 95% CI 0.42-0.67) [28]. In addition to ensuring normal serum magnesium levels, a number of medications have been shown to be effective, including beta-1 selective blockers, amiodarone, sotalol, and calcium channel blockers. However, data on other outcomes such as stroke, length of hospital stay, and other adverse events are limited [28-33]. In a network meta-analysis that included 22 trials (nearly 2900 patients), prophylactic beta-1 selective agents were more effective for preventing atrial fibrillation after thoracic surgery compared with other agents [30]. Guidelines from the American Association for Thoracic Surgery state that low-risk patients who are not on beta blockade prior to lung resection should not be started on a beta-blocker postoperatively. Patients who are taking beta-1 blockers prior to thoracic surgery should continue them perioperatively since beta-blocker withdrawal can increase the risk of atrial fibrillation [29]. For high-risk patients who are not taking beta-blockers, prophylactic diltiazem or amiodarone may be reasonable. (See "Atrial fibrillation in patients undergoing noncardiac surgery" and "Atrial fibrillation and flutter after cardiac surgery", section on 'Prevention of atrial fibrillation and complications'.)

●Smoking cessation – Smoking is a known risk factor for postoperative morbidity following lung resection. Current smokers are also noted to have longer hospital stay and increased likelihood of intensive care unit admission. Thus, it is recommended that all smokers abstain prior to all pulmonary resections [34]. (See "Strategies to reduce postoperative pulmonary complications in adults" and "Overview of smoking cessation management in adults".)

●Prehabilitation – (See "Overview of prehabilitation for surgical patients" and "Strategies to reduce postoperative pulmonary complications in adults", section on 'Pulmonary prehabilitation'.)

OPEN VERSUS MINIMALLY INVASIVE LUNG RESECTION — Surgical lung resection can be achieved using open or minimally invasive techniques (video-assisted thoracoscopic surgery [VATS], robotic-assisted thoracoscopic surgery [RATS]), each offering its own benefits and hindrances. A comparison is provided in the table (table 2). (See 'Thoracotomy exposures and techniques' below.)

Minimally invasive thoracic surgery (MITS) is increasingly being used to diagnose or treat conditions of the chest that were historically performed as an open thoracotomy. VATS quickly gained popularity after its introduction in the 1990s as thoracoscopic techniques and improved instrumentation for dissection, ligation, and division of major structures were developed [35]. Contrary to VATS, the acceptance of RATS has progressed more slowly due to higher costs, loss of haptic feedback, and steep learning curve. (See "Overview of minimally invasive thoracic surgery", section on 'VATS versus RATS'.)

Minimally invasive techniques have increasingly shown a benefit when compared with open thoracotomy. Several systematic reviews have reported faster recovery and shorter length of stay with MITS compared with patients who have had a thoracotomy with or without rib division [36-43]. Older patients are independent sooner with minimally invasive procedures compared with those with larger rib-spreading chest incisions, even though the extent of surgery internally is equivalent.

Individual postoperative metrics such as postoperative pain, pulmonary function, and costs studied in the realm of lung resection for management of malignancy are discussed below, although, as discussed above, lung resection may be required for several pulmonary diseases, and the data presented below offer indirect support for other indications.

Postoperative pain — It is well accepted that VATS offers the benefit of major pulmonary resection with decreased early postoperative pain [44]. Several studies have documented a decreased need for opioid analgesia, decreased hospital stay, and faster recovery and return to preoperative activities [45].

Similarly, RATS provides decreased pain scores immediately postoperatively with decreased opioid usage upon discharge, and shorter length of stay compared with open lung resection [46].

Minimally invasive lung resection confers an improved short-term quality of life (QOL) and decreased chronic pain as documented in several studies [47-50]. Few studies quantify long-term QOL, although one suggests the benefit may be present for up to one year following surgery [51].

Pulmonary function — Pulmonary function may be better preserved following minimally invasive pulmonary resection [52]. In a nonrandomized comparison, those who underwent minimally invasive lobectomy had improved recovery of forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and vital capacity (VC) compared with open thoracotomy. This improved recovery was superior up to two weeks postoperatively [44]. In another small comparison study, postoperative phase oxygen saturation, FEV1, and FVC were improved in the immediate postoperative period; however, there was no significant differences at approximately 12 months postoperatively [53].

Complications — In general, complications related to minimally invasive thoracic procedures are similar to those of the open surgical approaches. Common complications following lung resection include atrial fibrillation/flutter, postoperative atelectasis, respiratory failure, bleeding, surgical site infection, prolonged postoperative air leak, and bronchopleural fistula.

Postoperative arrhythmia occurs in 10 to 15 percent of lung resections and typically occurs within one to three days postoperatively with a similar incidence for open and minimally invasive approaches. In a secondary analysis of the American College of Surgeons Oncology Group (ACOSOG) Z0030 trial, the incidences of adult respiratory failure, adult respiratory distress syndrome, and atelectasis requiring bronchoscopy were low overall [54]. Compared with the open thoracotomy cohort, the minimally invasive cohort experienced none of these complications.

There is an increased risk for vessel injury during minimally invasive surgery; however, this does not uniformly translate to requiring conversion to thoracotomy or any increase in postoperative sequelae. Hemorrhage may be more difficult to control quickly via minimally invasive methods since blood may obscure camera visualization, but despite this, the frequency of blood transfusions is generally lower following VATS lobectomy compared with open thoracotomy (2.4 versus 4.7 percent, in one study [42]).

Prolonged postoperative air leak, defined as pulmonary leak of longer than seven days (the Society of Thoracic Surgeons [STS] defines a prolonged air leak as longer than five days), occurs in 10 to 15 percent of patients following lobectomy. Management is often conservative with ongoing chest tube drainage. Bronchopleural fistula, which is a direct communication of the bronchus and the pleural space, is a major complication of lung resection and occurs in 1 to 2 percent of lobectomies. Its incidence is higher following pneumonectomy (6 to 10 percent). Management requires reoperation for bronchial closure, pleural space drainage, and sterilization of the pleural cavity. (See "Bronchopleural fistula in adults".)

Unintended ligation and division of a bronchus or vessel has been documented in minimally invasive thoracic surgery [55,56]. Decreased "overview" and magnification used in minimally invasive techniques may contribute to this surgical mishap. Injury to the diaphragm, liver, or spleen may occur, particularly during port placement. Injuries to the liver or spleen can cause significant hemorrhage [57,58]. Some methods to avoid this complication include careful imaging review to identify anatomic variations, starting with cephalad ports or placement of a port that allows camera viewing at its tip, as commonly performed in laparoscopic surgery. Diaphragm injuries rarely cause severe morbidity, though they require repair.

Cost — The costs associated with open and VATS pulmonary resection appear to be similar, with the initial increased equipment costs associated with minimally invasive surgery offset by its reduced length of stay and fewer complications [59].

Despite the many benefits of robotic thoracic surgery, it has not achieved acceptance like VATS due to longer operative times and higher cost [60]. In one cohort study, there was a nearly $4600 increased incremental cost for RATS lobectomy compared with VATS. One author has suggested that the costs of robotic surgery are offset by decreased need for intraoperative monitoring devices and the ability to "fast track" patients with decreased hospital stay and procedural efficiency [61].

THORACOTOMY EXPOSURES AND TECHNIQUES — A thoracotomy is an incision through the chest wall used to provide exposure of the intrathoracic contents. The number and lengths of the incision(s) vary, with open thoracotomy using a single long incision compared with minimally invasive surgery, which uses one or more smaller incisions. The chosen approach to lung resection depends on the exposure needed to accomplish the resection. Video-assisted thoracoscopic surgery (VATS) is often chosen for its perceived benefits, but even in the era of minimally invasive techniques, open thoracotomy is still chosen by many thoracic surgeons of specific reasons. (See "Overview of minimally invasive thoracic surgery", section on 'Contraindications'.)

The various thoracotomy incisions are described below. Regardless of which is used, the basic principles are similar. The initial incision is made overlying the superior aspect of the chosen rib to avoid the intercostal neurovascular bundle (figure 4) and carried down through the subcutaneous tissue and intercostal muscles, typically by using sharp dissection to enter the pleura safely if there was a prior thoracotomy (eg, prior thoracotomy to enter the pleura safely). The pleura beneath the muscles is divided, taking care not to injure the underlying lung.

Open approaches

Posterior lateral thoracotomy — The posterior lateral thoracotomy incision through the fifth interspace is the most commonly used incision for lung resection. This incision provides adequate exposure for the majority of pulmonary resections.

The traditional moderate sigmoid incision of a posterior lateral thoracotomy (figure 5) is located one fingerbreadth inferior to the tip of the scapula extending posterosuperiorly between the spine and posterior border of the scapula, and progressing anteriorly toward the inframammary fold. The length of the incision is variable depending on the need for exposure. The thoracotomy can be performed either sparing or dividing the latissimus dorsi muscle, but the serratus muscle is commonly spared and retracted for entry into the thorax.

Sparing both the serratus and latissimus can also be performed, particularly in small, less muscular patients; this technique is more challenging in larger, more muscular patients. Muscle sparing can also be used when the latissimus dorsi muscle or serratus muscle will be used as a muscle flap for bronchial stump reinforcement.

Axillary thoracotomy/limited lateral thoracotomy — Located medial to the latissimus dorsi muscle, the axillary thoracotomy incision through the fourth intercostal space is a serratus muscle-sparing incision used for anterior mediastinal, hilar, and/or upper and middle lung resections. The axillary thoracotomy is typically reserved for upper lobe resection (right, left) and provides poor access to the posterior thorax.

Anterior thoracotomy — The anterior thoracotomy incision is performed by making an incision along the inframammary fold and dividing the pectoralis and anterior serratus muscles to reach the fifth intercostal space (figure 6). The anterior thoracotomy incision provides exposure for the anterior, upper, and middle lobes. Much like the axillary thoracotomy, the lower lobe is not well accessed via the anterior thoracotomy due to limited access to the posterior thorax.

Hemi-clamshell — The hemi-clamshell incision is a combination of an anterior thoracotomy and sternotomy with division of the sternum using an electric or hydraulic saw (figure 7). This incision is used for the resection of large tumors involving the apex of the upper lobe and/or anterosuperior mediastinum.

Clamshell — The clamshell incision provides bilateral thoracic and mediastinal access (figure 8). The incision spans the bilateral inframammary folds, with horizontal transection of the sternum.

Minimally invasive port placement — Minimally invasive lung surgery or VATS is typically defined as the use of thoracoscope (video) with thoracotomy but with no rib spreading. (See "Overview of minimally invasive thoracic surgery", section on 'Incisions'.)

Minimally invasive lung resections are performed through one or more small incisions, which are variable in size (figure 9). The surgeon performs the procedure while looking at the operative field on a monitor (figure 10). The incisions used to place the ports for the camera and instruments are created in their chosen locations in a manner similar to the open thoracotomy incisions described above, ranging in length from 0.5 to 8 cm depending upon the approach (eg, totally thoracoscopic, hand assisted). Insufflation of carbon dioxide can be used to aid with initial deflation of lung, or with entry into the chest.

CHEST TUBE PLACEMENT AND MANAGEMENT — Following lung resection, one or more chest tubes are placed in the hemithorax. The number of chest tubes placed varies with surgeon preference and the nature of the surgical procedure. Chest tubes are typically placed through a separate incision when a thoracotomy is performed. When a minimally invasive technique is performed, chest tubes can also be placed directly through the port sites. In a trial that randomly assigned 40 patients to thoracic drainage using the same intercostal space as the thoracotomy incision or traditional chest drainage using a separate incision, the mean lengths of hospital or intensive care unit stay, pain scores, and complications (including infection) were similar between the groups [62].

Chest tubes are connected to a chest drainage system consisting of three chambers: a fluid collection chamber for collection of postsurgical effluent, a "water seal" that collects air expelled from the thoracic space while preventing the entrainment of air into the thorax, and a vacuum chamber to which negative pressure or "suction" can be applied. The drainage system can be consolidated as a self-contained chest tube collection device (figure 11), or a three bottle system. Newer drainage systems offer the ability to better quantify the magnitude of a pleural leak to help direct chest tube care [63]. (See "Thoracostomy tubes and catheters: Indications and tube selection in adults and children".)

Postoperative management of chest tubes is directed by postoperative imaging, presence or absence of air leak (identified by the presence of bubbles within the water seal chamber), and the volume and/or character of drainage. Following both open and minimally invasive techniques, we typically place the chest tube to suction in the immediate postoperative period for at least 12 hours (overnight), then disconnect the suction, typically the next day, leaving the chest tube to water seal.

The decision to place a chest tube to suction versus water seal if a postoperative pleural leak is present is controversial. Up to 44 percent of patients following lung resection have a postoperative air leak [64]. Retrospective studies have suggested that pleural leaks may seal more quickly if suction can be eliminated (water seal for wet drainage systems) [64-71]. Some suggest a short period of postoperative suction, while others suggest water seal beginning immediately postprocedure [64,66]. Randomized trials have compared outcomes for patients assigned to chest tubes placed to water seal or to suction following lung resection following a brief period of suction [64,65,68-70]. A meta-analysis of seven trials that included 1139 patients found no difference in the incidence of prolonged air leak for patients who received ongoing suction compared with those who did not; however, there was substantial heterogeneity among trials [72]. Whether ongoing suction affects air leak or chest tube duration remains uncertain, as this meta-analysis and an earlier meta-analysis reached different conclusions [72,73].

Chest tubes must be evaluated several times daily to ensure patency of the tubes, checking for kinks or occlusions, and to assess for their ongoing need. We leave the chest tubes in position as long as any air leak from the lung remains, or the fluid effluent volume is >300 mL/day. Upon resolution of pleural leakage and collection of minimal fluid drainage, the chest tube is removed at the bedside.

Persistent air leak — For patients who do not resolve their air leak, the patient can be discharged to home with a one-way flutter valve [74,75]. The authors' practice is to take the tube out at approximately three weeks on first follow-up visit. Until the tube is removed, antibiotics are given to the patient.

Risk factors for persistent air leak include severe emphysematous lungs, an incomplete fissure that may have required division, and cauterizing lung parenchyma. In a study of 669 postoperative patients, other factors included male sex, steroid therapy, and lobectomy [76]. Most air leaks sealed within two weeks with conservative care (one-way valve).

Techniques that can be useful for minimizing air leak include gently handling of lung tissue with lung clamps or sponge gauze, minimizing cautery to divide fissures, and using a linear cutting stapler, when possible.

SUMMARY AND RECOMMENDATIONS

●Pulmonary resection – Pulmonary (lung) resection is used for the treatment of a variety of diseases, including primary lung malignancies, metastatic disease to the lung, a variety of benign lung diseases when medical therapies are no longer effective, and more severe traumatic injuries. In addition, pulmonary resection is also a means of diagnosis for some pulmonary diseases. (See 'Indications' above.)

●Preoperative evaluation – The preoperative evaluation includes anatomic and cardiopulmonary assessment to determine the risk of pulmonary resection. The evaluation includes history and physical examination, pulmonary function tests including calculation of predicted postoperative pulmonary function values, and lung imaging. If imaging studies of the chest have not been performed within six to eight weeks of the planned thoracic surgery, they should be repeated, particularly for inflammatory or infectious etiologies. For malignancy, imaging within 10 to 12 weeks is sufficient. (See 'Preoperative evaluation and preparation' above.)

●Types of lung resection – The various types of lung resection are broadly classified as anatomic resections that follow the segmental anatomy of the lung (figure 1) and non-anatomic resections. Anatomic resections include segmentectomy, lobectomy, pneumonectomy, and sleeve resection. The extent of resection needed is based upon the size, location, and type of lesion found within the lung. For malignant disease, the ability to obtain a negative margin is an important consideration in determining the choice of resection. (See 'Lung anatomy and types of lung resection' above.)

●Surgical approach – Surgical lung resection can be achieved using open or minimally invasive thoracotomy techniques (video-assisted thoracoscopic surgery [VATS], robotic-assisted thoracoscopic surgery [RATS]). Minimally invasive techniques have increasingly shown a benefit compared with open thoracotomy with faster recovery and shorter length of stay. Complications related to pulmonary resection are similar for minimally invasive and open thoracotomy approaches. Overall costs are similar, with the initial increased equipment costs associated with video-assisted thoracoscopic surgery offset by its reduced length of stay. (See 'Open versus minimally invasive lung resection' above.)

●Use and management of thoracostomy tubes – Following lung resection, one or more chest tubes are placed in the hemithorax. The number of chest tubes placed varies with surgeon preference and the nature of the surgical procedure. The decision to place a chest tube to suction versus water seal if a postoperative air leak is present is controversial. Retrospective studies have suggested that pleural leaks may seal more quickly if suction can be eliminated (water seal for wet drainage systems); however, the effect of suction on air leak duration remains uncertain. (See 'Chest tube placement and management' above.)