The application of thoracoscopy can be traced back to 100 years ago, when Dr. Jacobaeus first reported his experiences in the diagnosis and treatment of pleural effusions by thoracoscope in 1909 [1]. Most patients who needed to undergo thoracoscopy at that time suffered from pulmonary tuberculosis [2]. The development of fibro-optic light transmission, the illumination and the image processing techniques, as well as the refinement of related instruments made video-assisted thoracoscopy more easily and broadly applied after the 1990s [3, 4]. And now video-assisted thoracic surgery (VATS) has become a basic and important technique for a thoracic surgeon.

Frequently, minimal invasive thoracic surgery for lung cancer includes three approaches: (1) VATS, (2) Hybrid VATS and (3) Hand-assisted VATS. VATS usually refers to thoracic surgery that involves insertion of instruments through one (Uniport) or two to four small chest incisions under two-dimensional video images, and hand-assisted VATS mainly refers to thoracic surgery performed by inserting the surgeon’s hand into the chest cavity through one of the chest incisions to control the target organs under a two-dimensional video images. A “Hybrid VATS” was defined as using a rib spreading retractor and operates directly through the thoracotomy (usually 8–10 cm in length). In these cases the camera is only used for illumination. Recently VATS can be performed through uniportal or subxiphoid approach for lung lesion.

In 2012, the VATS Lobectomy Consensus Meeting was held in Edinburgh, UK, which marked the 20th anniversary of this procedure. For the first time in history, consensus agreements on several important issues on VATS lobectomy, including its definition, patient eligibility, surgical standard of care were reached [5]. Since then, the Cancer and Leukemia Group B (CALGB) definition has become the globally accepted state-of-the-art VATS lobectomy technique [6], which comprised (1) no use of rib-spreading, (2) a maximum length of 8 cm for the utility incision (3) individual dissection of pulmonary vessels and bronchus. While a small retractor isonly acceptable in selected circumstances, such as conducting complex procedures (e.g. sleeve resection) or delivery of a large specimen.

In the current era, a prospective, randomized comparison of open versus VATS lobectomy for lung cancer will likely never occur, leaving us to rely on the best available current evidence to draw meaningful clinical conclusions. In the following sections, several important studies to address this issue.

To the best of my knowledge, there has been no publication thus far demonstrating inferior outcomes of VATS lobectomy compared to open thoracotomy. Without a doubt, VATS has completely revolutionized modern thoracic surgery and significantly improved patient outcomes over the last two decades.

After pulmonary resection, there are substantial changes in the physiology of the cardiopulmonary system. Lung resection decreases postoperative pulmonary function as measured by forced expiratory volume in the first second (FEV1) and the shuttle walk test [17]. While FEV1 decreases maximally the first few days postoperatively, it improves to only 75 % of predicted values at 1 month and 85 % at 3 and 6 months [17]. Similarly, the shuttle walk test is 70 % of its preoperative value when assessed at 1 month and improves to 84 % of preoperative values when reassessed at 6 months [17]. The immediate postoperative decrease is related to reduced respiratory mobility of the ribs and diaphragm after a thoracic operation, predominantly due to pain. This subsequently leads to decreased pulmonary expansion, alveolar collapse, and subsequent atelectasis [18].

The changes in pulmonary spirometry are associated with the degree of pulmonary resection performed. For patients undergoing a segmentectomy, FEV1 and forced vital capacity (FVC) are relatively preserved [19]. After lobectomy, and once recovered from the initial postoperative period, spirometry values for FVC, FEV1 and total lung capacity (TLC) are reduced by 7–10 % [20]. For those patients undergoing pneumonectomy, FVC, FEV1, and TLC are typically decreased by 30–35 % [20]. In patients undergoing wedge or lobectomy, no postoperative changes in cardiac hemodynamics are observed [21]. Pneumonectomy is associated with elevated right ventricular volumes at end-systole and end-diastole, while right ventricular ejection fraction is decreased by 10 % [21]. The decreased ejection fraction after pneumonectomy is likely due to the increased afterload, while the increased right heart volume compensates to improve ejection based on the Frank-Starling Curve. These changes underline the importance of preoperative evaluation to determine which patients are likely to tolerate surgery without increased cardiopulmonary risk.

General anesthesia adversely affects pulmonary function by relaxing respiratory muscles leading to a reduction in functional residual lung volume. This in turn collapses bronchioles leading to atelectasis [22]. These changes contribute to postoperative hypoxemia and can last many days after surgery. A thoracotomy incision reduces chest wall compliance leading to decreased total lung volume due to limited expansion. Appropriate pain control and minimally invasive procedures are thought to limit this physiologic restriction.

Induction chemotherapy reduces diffusion capacity of the lung for carbon monoxide (DLCO) in 15 % of patients [23]. This reduction does not typically affect clinical symptoms and only 2 % of patients are ineligible to proceed with surgery based on the change in DLCO. For heavy smokers, the reduction after induction chemotherapy is greater. The relation of induction chemotherapy to increased post-operative complications is controversial [23, 24]. Due to pulmonary changes after induction chemotherapy, an updated assessment of the patient’s lung function should be obtained [25].

Lung resection is associated with the development of postoperative complications including pulmonary, cardiovascular, infectious, surgical, and others (Table 2.3). Some postoperative complications are associated with specific preoperative patient characteristics, permitting risk stratification. The two most common categories of complications, pulmonary and cardiovascular, are listed in Table 2.4 with their preoperative predictive variables. Aside from demographics, significant predictive ability is found in cardiac and pulmonary function. For this reason, specific evaluation of these parameters should be performed in all patients undergoing major lung resection regardless of the surgical approach [26].

Physiologic assessment of lung function includes measurement of both ventilatory capacity and gas exchange capacity. Each of these is an independent predictor of postoperative complications, especially cardiopulmonary complications [27–32]. The most useful spirometric parameters are the forced expiratory volume during the first second expressed as a percent of predicted (FEV1%) and the predicted postoperative value for this parameter estimated based on the amount of lung to be resected (ppoFEV1%). Gas exchange capacity is assessed by measurement of the diffusing capacity of the lung for carbon monoxide (DLCO), which is an estimate of pulmonary capillary surface area or pulmonary capillary blood volume. The value is often corrected for hemoglobin, which provides a more accurate assessment of gas exchange ability. In contrast, corrections for lung volume are not typically performed, as the basis for such corrections are not physiologically sound. DLCO is usually expressed as a percent of predicted (DLCO%) or as an estimate of expected postoperative function (ppoDLCO%).

Predicted postoperative values are more accurate than preoperative values in estimating the risk of postoperative complications as well as long-term survival [33, 34]. Preoperative alterations in FEV1% may be related to underlying lung disease, neuromuscular disorders, prior lung surgery, extreme obesity, and other conditions (Table 2.5). Alterations in DLCO% may be related to serum hemoglobin level, primary lung disease, disorders of the pulmonary vasculature, and cardiac insufficiency. Predicted postoperative values of FEV1% and DLCO% usually can be accurately estimated using the functional segment counting technique [35].

The accuracy of such estimates can be affected by the location of the resected lobe (upper versus lower) and the presence of heterogeneous distribution of emphysematous changes [36]. In patients with heterogeneous lung disease, prior lung resection, or major airway obstruction, more accurate estimates are obtained using quantitative ventilation/perfusion scans or quantitative computed tomography [37–39].

Exercising testing is also a useful method for evaluating patients’ postoperative risk after lung resection, as it assesses the interactive function of the respiratory and cardiovascular systems [40–45]. Although the routine use of exercising testing provides slightly more accurate risks of postoperative complications, its use is usually reserved for patients who are identified as being at increased risk based on pulmonary function testing. Selective use decreases the costs and duration of the preoperative evaluation. Exercise testing can be performed using low technology methods (stair climb, 6 min walk test, shuttle test) or using high technology testing, usually measurement of peak oxygen consumption during maximal exercise (peak VO₂), which is typically performed during cycle ergometry. Exercise testing may not be possible in some patients because of lower extremity weakness, cardiovascular disease, or other physical limitations, and is often precluded because of the lack of availability the required equipment and expertise to use it.

The American College of Cardiology and the American Heart Association (ACC/AHA) guidelines stratify procedures by their level of risk and in turn identify patients who have clinical risk factors placing the patient at increased cardiac risk during non-cardiac procedures [46]. According to the ACC/AHA, major lung resection qualifies as having intermediate risk (a cardiac risk of 1–5 %). If patients are undergoing an elective lung resection, they should be evaluated and screened for severe or increasing angina, recent myocardial infarction (MI), decompensated heart failure, severe arrhythmias, or severe valvular disease. If any of these symptoms or history is present, the patients should have an appropriate cardiac work-up and management prior to an elective lung resection. If no history is present, patients are then evaluated for typical physical activity levels based on metabolic equivalents (METs). One MET is expended during effectively taking care of one’s self daily by dressing and feeding. Four METs are expended doing light work around the house or climbing a flight of stairs. If a patient meets the 4 MET threshold, the likelihood of important cardiovascular disease in the absence of symptoms is low and the operation can be planned. If less than 4 METs are typically expended or if METs are unknown, clinical risk factors of ischemic heart disease, heart failure, stroke, diabetes, and renal insufficiency are evaluated. If none is present, proceeding with the operation is appropriate. If one or more risk factors are present, a non-invasive stress test should be considered prior to scheduling an operation.