Video-Assisted Thoracoscopic Surgery Versus Open Thoracotomy

Contrary to conventional incisions—such as posterolateral thoracotomy—port holes require smaller incisions which would be associated with reduced inflammatory response, better respiratory mechanics, improved respiratory muscle recovery, and certainly lesser pain. Thoracoscopic procedures have become more frequently comprising a wide range of procedures and represent a reliable minimal invasive alternative for high-risk patients.

Initial reports highlighted benefits of VATS in reducing overall complications and decreasing hospital stay.⁶ Furthermore, the thoracoscopic approach was found to be more favorable in terms of intensive care unit (ICU) stay time and postoperative pneumonia despite preoperative comorbidities.⁷ In several studies, it was shown that VATS minimized complications and enhanced the quality of life in the postoperative period,⁸ with less postoperative pain,⁹ better pulmonary function outcomes,¹⁰ shorter overall hospital length of stay, and faster return to normal activities.^11,12 In 2010, the American College of Surgeons Oncology Group published data of approximately 1000 patients and found that thoracoscopic lobectomy was associated with lower pulmonary complications (atelectasis, chest tube drainage) and shorter length of stay.¹³ In 2016, the European Society of Thoracic Surgeons reported results from 235 centers which included 5500 patients (selected among 26,000 according to propensity score).¹⁴ Major cardiopulmonary complications were significantly lower in the VATS group compared with the thoracotomy group (15.9% vs. 16.9%; P = .0094). Length of stay was shorter among the thoracoscopic group as expected (P = .003). Mortality at discharge was also lower in the VATS group, which, however, needs to be cautiously commented according to authors because of some missing data. A more recent trial by Nwogu et al. has compared VATS with open thoracotomies as length of stay (LOS) for primary outcome. The VATS group had significantly lower LOS (5.4 vs. 8 days; P < .001). Moreover, incidence of complications was consistent with the primary outcome favoring the VATS group (6% vs. 16%; p = .0001). Thoracoscopic surgery is associated with reduced injury, stress response, and may enhance recovery of patients in thoracic surgery. The short-term outcome appeared favorable for thoracoscopic surgery.¹⁵

In the recently published: “Guidelines for enhanced recovery after thoracic surgery (ERATS),” VATS was recommended for lung resection for early-stage lung cancer with a “high” evidence level and “strong” recommendation grade, stating that “the benefits are even more marked in patients with poor respiratory reserve.”¹⁶

Long-term results are controversial; studies show either similar results of both approaches, or better results for VATS in terms of survival. Sugi et al. reported a similar oncologic outcome in VATS compared with conventional lobectomy for the following 5 years.¹⁷ Similarly, Whitson et al. did not find any difference in survival between thoracoscopy and thoracotomy.⁷ Recently, one center study by Oda et al. in patients with early lung cancer, reported better 5-year survival in patients undergoing thoracoscopic resection.¹⁸ Short-term variables (blood loss, hospital stay, C-reactive protein [CRP] levels) were also significantly advantageous in the thoracoscopy group. The authors speculated that it could be related to lesser tissue damage and inflammatory response screened by CRP values. Other studies confirm that the long-term (5 years) survival was better with VATS when compared with open surgery for early-stage lung cancer^19,20 (Fig. 31.1). Another recent study comparing VATS to open thoracotomy for cT1–T2 N1 M0 nonsmall cell lung cancer (NSCLC) showed that VATS had no significant difference in long-term survival, with shorter LOS and similar nodal upstaging rates, considering it suitable for the treatment of NSCLC.²¹

Today, VATS is recognized by international guidelines as preferred over thoracotomy for treatment of early-stage NSCLC.²²

An interesting retrospective study revealed similar costs for thoracoscopic or traditional lobectomies.²³ Operative cost was significantly higher with VATS, whereas total hospital cost was similar with traditional lobectomy, but a shorter stay in the thoracoscopic group and increased patients’ turnover abolished the temporary economic issue of conventional approach.

Uniportal Video-Assisted Thoracoscopic Surgery

In a period of less than 20 years, there has been a rapid evolution in the surgical technique of VATS: the classical three-port approach was initially changed to a two-port strategy, and soon afterwards, there was a trend toward a one-port technique, where the camera was moved to the utility port, the camera’s port was abandoned, and the entire procedure was completed using just one incision. Uniportal VATS was first described in 2001, and then reported for simple procedures, such as lung biopsies and spontaneous pneumothorax in 2005.²⁴

The expansion of the technique was achieved following the developments by Gonzalez-Rivas et al. in the next 10 years, where the technique was used for more complex procedures, such as pulmonary anatomic and complex resections for the treatment of lung cancer.²⁵ This strategy achieves a direct vision of the targeted tissue and of the pulmonary hilum. This fact, together with the accession of parallel instrumentation, achieves an approach similar to the open surgery view and maneuvers, making the surgeons feel more comfortable while operating, compared with other VATS strategies. Today, the technique has been adopted, reproduced, and reinforced by the surgical community; however, it is limited by the significant learning curve.^26,27

Compared with conventional VATS, UniVATS has been shown to be beneficial with shorter LOS in the hospital, duration of drainage, and reduced overall morbidity.²⁸ One—instead of three—incision is associated with less inflammation and less pain, leading to reduced postoperative complications, with an overall better outcome. It has been used not only in operations like lobectomy or wedge resection but also in more complicated procedures like pneumonectomy, sleeve resection or tracheal and carinal resections.²⁷

It should be noted that some trials report no difference between uniportal and multiport VATS lobectomy. Perna et al. have compared uniportal video-assisted lobectomy (group A; n = 51) and other video-assisted thoracoscopic lobectomy techniques (group B; n = 55). The median visual analog pain score in the first 3 days did not show statistically significant differences. Likewise, the median morphine use in the first 3 days did not show statistically significant differences. There was no difference in timing to remove the paravertebral catheter and the chest drain and the duration of the postoperative hospital stay. There was no difference in postoperative complications.²⁹ In ERATS protocols, it has been stated that “The number of ports used does not appear to affect outcomes, and so, one VATS approach cannot be recommended over another.”¹⁶ As a matter of fact, more and more high quality studies are still necessary to evaluate the potential benefits of this technique. The anesthetic management, including ventilation, for uniportal VATS does not differ from that performed for classical VATS.³⁰

Subxiphoid Uniportal Video-Assisted Thoracoscopic Surgery

The subxiphoid approach began its evolution in 1999.³¹ First implemented for mediastinal pathologies, in 2014, a subxiphoid UniVATS left upper lobectomy was reported.³² Following that, many procedures, such as wedge resections, segmentectomies, lobectomies, and even pneumonectomies have been performed by this approach. There are two major advantages of this technique: (1) intercostal nerve injury related to the incision and instrumentation is avoided, and (2) it will allow approaching bilateral lesions from a single incision without changing the patient’s position. Avoidance of intercostal nerve injury has been shown to be associated with significantly lower postoperative pain compared with intercostal UniVATS.³³

Robotic-Assisted Thoracic Surgery

Robotic-assisted thoracic surgery (RATS) is covered in Chapter 52 in this book in detail. It should be considered as an important step of the rapid changes in the practice of thoracic surgery and anesthesia. A subcostal VATS approach (with or without robotic help) is also one of these promising steps.³⁴

Preoperative Risk Stratification

Preoperative evaluation with risk stratification and scoring systems are extensively explained in Chapter 8 of this book. Regarding VATS, it should be noted that some systems take also “operation-related” risk factors into consideration (e.g., considering pneumonectomy as “high-risk”); however, to our knowledge, none of these risk stratifications and scoring systems differentiated between open thoracotomy and VATS as different risk factors. The risk of a patient undergoing open thoracotomy with similar comorbidities and extent of resection is higher than the patient undergoing VATS. This part will therefore focus on “common” criteria.

Improvements of surgical techniques and advances in anesthesia have resulted in an overall improved outcome. But at the same time, those improvements allowed patients who previously were not considered surgical candidates to now be offered major resections. These patients are older, with multiple comorbidities which in many cases are uncontrolled or not treatable, making the perioperative period challenging, and probably leading to an increase in postoperative complications and decrease survival.³⁵ Therefore preoperative evaluation and preparation of patients who will undergo a VATS procedure should be revised separately.

Perioperative mortality represents a serious worldwide public health problem. Thoracic surgery deserves special interest because postoperative complications are significantly high (up to 27% in a recent review) (Fig. 31.2).³⁶ Preoperative assessment and screening of high-risk patients must identify the patient that would benefit from optimizing measures. Increase in patient comorbidities and an increase in awareness during the perioperative period is a relatively new topic which is part of the ERAS (enhance recovery after thoracic surgery) guidelines.¹⁶ A team approach makes sense for this population while assessing cardiac risk, planning optimizing measures, organizing oncologic follow-up, and judging operability. Thus an experienced team should be composed of a pulmonologist, oncologist, thoracic surgeon, and anesthesiologist as well as the patient and the relatives.

The first step of preparation can be initiated with cardiac evaluation to determine preexisting risk factors and to treat before surgery. The revised cardiac risk index has been adapted for thoracic surgery (Table 31.1).³⁷ Three to four subgroups are defined in this scoring system as A (0 point), B (1–1.5 points), C (2–2.5 points), or D (>2.5 points); the latter two described as high risk. The incidence of cardiac event varies in groups for A less than 1.5%, for B 5.8%, for C 19%, and for D 23%. The thoracic revised cardiac risk index (ThRCRI) can discriminate high-risk patients—groups C and D³⁸—and may allow for identification of patients who would benefit from additional cardiac evaluation.

A subsequent cardiac issue—generally neglected—is right ventricular (RV) function, which remains affected from the second postoperative day to the second month.³⁹ Postthoracotomy impaired RV ejection fraction is a recognized phenomenon usually related to elevated pulmonary vascular pressures but also to reduced compliance. Thoracoscopic surgery compared with thoracotomy offers advantages in terms of RV function in the early postoperative course for elderly patients.⁴⁰ Not surprisingly, the extent of lung resection directly affects RV changes. Pneumonectomy is found to be associated with more pronounced RV dysfunction compared with lobectomy.⁴¹ Further studies are needed to determine the best predictor for preoperative assessment of RV. Natriuretic peptides seem promising in thoracic patients to detect some CV complications, especially for prediction of postoperative atrial fibrillation.^42,43

Pulmonary evaluation for lung surgery includes spirometry, diffusion capacity, and exercise tests if needed, as summarized in Fig. 31.3.³⁷ Although patients with low risk can be cleared for surgery, in high-risk patients, cardiopulmonary exercise testing should be considered. In a newly introduced algorithm, a slope of minute ventilation to CO2 output ratio seems promising.⁴⁴ A slope of more than 34 was associated with increased mortality. In fact, an increased ratio could be explained by respiratory inefficiency and appeared to be associated with increased mortality.⁴⁵

History

Historically, lung isolation essays were started with physiologic animal studies by C. Bernard and E. Pflüger in the 19th century. The setup was adapted to volunteers by Loewe and von Schrotter at the beginning of the 1900s, again, for cardiopulmonary physiologic studies.⁵⁶ Introduction of the endotracheal tube (ETT), by Gale and Waters, followed by the introduction of the double-lumen tubes (DLTs). The 1950s presented the first double-cuffed double-lumen tube described by Carlens. DLTs designed by Robertshaw were introduced first in red rubber in the 1960s; 20 years later, they are marketed as disposable polyvinyl chloride, and are used worldwide. A rubber bronchial blocker (BB) was first used (positioned by radiography) in the 1930s by Archibald.⁵⁷ The use of the fiberoptic bronchoscope was considerably later in the 1980s and constituted a huge advancement in thoracic anesthesia.

Indications

The historical classification of indications for one-lung ventilation (OLV; namely, absolute vs. relative) is not target-oriented and sometimes confusing. From that historical point of view, every VATS operation should be considered as an “absolute” indication of OLV. Currently, thoracic anesthetists agree on the classification of lung isolation versus lung separation: the isolation of the lungs means a completed “anatomic” sealing (conditions like massive pulmonary bleeding, air leak as a result of bronchopleural fistulae, pneumonia with pus, etc.); whereas the separation of the lung means a “functional” sealing.⁵⁸ Because most VATS operations require just lung separation and not isolation, both DLTs and BBs can be used. DLT is the most common device used in OLV, but it should be known that in some conditions, BBs can be a more rational alternative (Table 31.2).

Challenges During Video-Assisted Thoracoscopic Surgery

The primary objective of lung isolation is to protect the healthy lung to ensure gas exchange in the presence of pulmonary hemorrhage, bronchopleural fistula, etc. On the other hand, lung separation (and sometimes also isolation) is necessary to improve surgical exposure especially in thoracic and also cardiac, mediastinal, orthopedic, or esophageal surgeries.

• • Anesthesiologists must be aware of the necessity of lung collapse for thoracoscopic surgeries to ensure adequate exposure. In fact, it can be considered that the smaller the incision, the better collapsed the lung should be. If the lung is not adequately collapsed, it would not be possible to achieve an optimal still surgical exposure. In some open thoracotomies, this compromise can be compensated by the large incision; however, it can lead easily to a failure during VATS.
  
• • A total collapse is necessary not only for an optimal surgical exposure: in VATS, stapling devices are used for resection. If the lung is not well collapsed, the risk of air leak from the staple lines increases.
  
• • Continuous positive airway pressure (CPAP) to the nondependent lung is considered as a method of choice to treat—and prevent—hypoxemia during OLV. In VATS, the application of this technique is not practical since the inflate lung reduce the surgeon view.

Double-Lumen Tubes Versus Bronchial Blockers (See Table 31.2)

Using the DLTs is the most common method for lung isolation; referred to as the “gold standard” by Cohen⁵⁹: many anesthesiologists consider it as the easiest method, mainly because they are familiar with it. A left DLT is preferable for the vast majority of thoracic procedures because a right DLT is more difficult to place and it is more complicated to maintain the optimal position to ventilate the right upper lobe. There are some limited indications for use of a right DLT, such as left main bronchial lesions with associated surgery (e.g., left pneumonectomy or sleeve resection) or an external cause of obstruction of the left main bronchus by an aneurysm of the descending aorta.

Available sizes of DLTs for adults vary between 26 Fr and 41 Fr and smallest sizes can be selected in children over 8 to 10 years old. One of the major challenges of a DLT is the lack of an accurate method to select the proper size and also the optimal insertion depth.

*Proper size: For a left-sided DLT, it is recommended to measure the width of the left main bronchus and to choose the largest tube that can fit safely that bronchus⁶⁰ (Table 31.3). For a right-sided DLT, this issue remains unsolved.

*Optimal insertion depth: The depth of the DLT can be most accurately determined with fiberoptic bronchoscopy (FOB). A blind technique could easily be associated with 50% incidence of malposition.⁶¹ Formulas based on height have been proposed to estimate optimal DLT depth.⁶²

A major concern regarding DLTs is airway trauma because of tube and stiffness and the larger diameter. Other risk factors are lack of flexibility (especially compared with BB), malposition (and multiple attempts to place), or rotation angle in one study (safer with 180 degrees instead of 90 degrees).⁶³ A new meta-analysis comparing a DLT with BB affirmed that a DLT was more commonly associated with an increase in airway trauma presenting as sore throat.⁶⁴ However, a DLT had significantly less malposition and was more rapidly inserted with a difference of 1 minute, which may be statistically significant but is obviously clinically irrelevant.

A relative new innovation of DLTs has an embedded camera at the tip of the tracheal lumen. This camera enables a continuous view of the carina and ensures the optimal position of the tube. The authors suggest that these types of DLTs can be a good choice especially for (but not excluded to) robotic VATS procedures, where the approach of the anesthetist to the patient can sometime be limited.

Fiberoptic Bronchoscopy

Use of FOB in thoracic anesthesia, and especially during VATS, is crucial:

• • One of the most common reasons of hypoxemia during OLV is dislocation of OLV devices, which is much more common (e.g., 38%) for less experienced anesthesiologists in low-volume centers.⁶⁹ In another study, more than one-third of the DLTs, which were thought to be correctly positioned according to auscultation, required repositioning after use of FOB.⁷⁰
  
• • For the intubation with a DLT, there are two possible methods:
  
  
  
  • • After passing a DLT with direct laryngoscopy, confirmation with FOB is essential to ensure that the bronchial tube is in the correct bronchus, and its depth is optimal (cuff 3–5 mm below the carina).
    
  • • FOB can be used from the beginning as a guide: the intubation is performed with the FOB in the bronchial lumen of the DLT to guide under direct vision into the correct bronchus. Afterwards, the depth should be confirmed with via bronchoscopy through the tracheal lumen.
  
  
• ߦ Cohen, Arndt, and Uniblocker BBs have to be positioned with FOB.
  
• • Position of the DLT or BB should be checked again with FOB:
  
  
  
  • • After lateral decubitus position.
    
  • • In changes in oxygenation, gas exchange, ventilation pressures.
  
  
• ߦ Specific for VATS: contrary to open thoracotomies, reinflation of the remaining lobe(s) during the stapling process can impair the surgical visualization. At this stage, visual control via FOB can ensure the patency of the bronchi of not resected lobe(s).

1. 1. DLTs have to be preferred to Arndt, Cohen, and Uniblocker.
   
2. 2. EZ-Blocker can be used because the resistance of the Y at the distal tip on carina can be positioned without FOB. In this case, careful auscultation would avoid the possibility that both ends of the blocker have been introduced to the same bronchus.
   
3. 3. Position control of DLT should be performed with auscultation: first in two-lung ventilation, followed by the sequential blockade of both lumens.
   
4. 4. New, but extensively introduced in anesthesia practice, ultrasound (US) was found to be useful in confirming adequate position of left DLT.⁷¹ It is feasible in the intercostal view to distinguish the ventilating lung from the collapsed one. To and from movement of ventilated lung is associated with pleura seen as “lung sliding,” whereas collapsed lung appears with “lung-pulse sign” because of pleural movement with heartbeat.
   
5. 5. Electric impedance tomography (EIT) can be used to confirm the correct placement of a DLT.⁷²
   
6. 6. Finally, DLT and ETT with an embedded camera (VivaSight®). The DLT has the camera at the tip of the tracheal lumen to monitor the position of the bronchial lumen continuously. The ETT has the camera at the distal tip so that BBs (including the one of the same companies) can be positioned under continuous view.^73,74

Total Collapse of the Nonventilated Lung

(Fig. 31.4)

In open thoracotomies, some degree of “partial” collapse can be tolerated by the surgeons. On the contrary, in VATS, a total collapse of the lung is inevitable. Even apneic periods can be necessary to create an immobile surgical area for manipulation in the hilum or mediastinum.

Some maneuvers can help to create a total collapse:

1. 1. Immediately after starting the OLV, open to air or suction to the lumen of DLT or BB to the nonventilated lung should be applied. A relatively low level of negative pressure (–20 cm H₂O) is usually enough to improve the speed and quality of lung collapse. The negative pressure and the suction catheter itself achieve both the suction of air from the lung and the prevention of passive entrainment of air into the lung.
   
2. 2. Although it is a general rule to keep the time of OLV as short as possible, it can make sense to start the OLV immediately after the positioning of the patient to the lateral position. This would not require a significantly long time, but can help to achieve a collapsed lung when the trocar enters the thorax. Moreover, this time can also be used for a positive end-expiratory pressure (PEEP)-titration in the patients (see the next part of this chapter). Remember that in “OLV with closed chest,” if the lumen of the DLT to the nonventilated lung is open to atmosphere, so-called “passive paradoxical ventilation” can occur, and a tidal volume (V_T) of approximately 130 mL can be inhaled to the nonventilated lung (during expiration).⁷⁵ This means, starting OLV earlier may lead to a delayed collapse, which can be avoided by applying the suction immediately after OLV.
   
3. 3. During two-lung ventilation before OLV, lungs can be ventilated with a fraction of inspired oxygen (F_iO2) of 1.0 for a period of some minutes. Nitrogen is the “natural CPAP” of the alveoli preventing/delaying the collapse. Wash-out of the pure oxygen from the denitrogenated lung would obtain a faster and better collapse of the lung. After the initiation of OLV, a recruitment maneuver (RM) to “open” the dependent lung would be necessary; adding some air (if the oxygen saturation [SpO2] >90%) would also prevent further atelectasis of the dependent lung.
   
4. 4. To repeat one suggestion in this chapter that the use of CPAP during VATS is limited, however oxygen insufflation without expanding the lung may provide some improvement in oxygenation through apneic oxygenation.