VATS Lung Surgery

TSRA Content:

Author: Daniel P. Dolan, MD

This is a revision and update from the previous edition of the TSRA Primer in Cardiothoracic Surgery written by Benjamin Wei, MD

Thoracoscopic Pulmonary Lobectomy

Preoperative Evaluation:
1) What type of resection is appropriate to remove the nodule/mass?
2) Will the patient tolerate having this amount of lung removed without requiring supplemental O2 at home after surgery?

Thorough review of the chest CT scan usually reveals whether a nodule/mass can be safely removed with a lobectomy; final extent of resection is made intraop. Patients with tumors near the major vessels and lobar bronchi may need to undergo a more detailed preoperative evaluation to determine if they are a candidate for lobectomy. IV contrast is useful to determine if vascular structures are involved, while bronchoscopy with endobronchial biopsies should be performed ahead of time to determine if the patient will need a bilbectomy, sleeve lobectomy, or pneumonectomy instead of a standard lobectomy.

A tumor that crosses a fissure may require either an extended parenchymal resection or one of the aforementioned more extensive procedures. Invasion of the chest wall necessitates chest wall resection and possible reconstruction. Superior sulcus tumors require neoadjuvant chemoradiation prior to surgery with reimaging after to determine resectability.

The patient’s baseline functional status and the CT appearance of their lungs are taken into account when pulmonary reserve is questionable. Exercise testing for V02 max can also be used in special cases. If it does not appear that the patient will tolerate a lobectomy, a sublobar resection such as wedge resection or (preferably) anatomic segmentectomy may be an option. In keeping with the mission of this primer, only the 5 standard lobectomies will be described here.

Anesthetic Considerations:
Thoracoscopic lobectomy requires single lung ventilation. A dual lumen endotracheal tube is typically used, though a bronchial blocker (easier to place for left-sided resections) may suffice if the patient’s airway is very difficult or too small to accommodate a double lumen tube. Minimizing the "down-side" tidal volume, which can be lowered to 300 ml or less in most patients, improves visibility and decreases motion on the side of the thoracoscopy. Epidural analgesia can be offered to optimize postoperative pain control if there are no contraindications. An arterial line is placed given the risk of vascular injury and to monitor blood gases during single-lung ventilation. Prophylactic antibiotics, urinary catheter, a warming blanket, and sequential compression devices are standard for lobectomy.

Positioning:
The patient is placed in the lateral decubitus position on a bean bag as explained in the "thoracotomy" chapter; some institutions will use blanket/foam rolls as an alternative. Proposed thoracoscopic incision sites, the tip of the scapula, and the location for a potential thoracotomy are marked prior to draping. The standard incisions are located in the 8th intercostal space posterior to the anterior superior iliac spine for the camera port, and in the 5^th intercostal space near the anterior axillary line (but avoiding the breast in women) for the utility port. The camera will be placed via the utility port at times to facilitate dissection and division of structures. Port number and locations will vary between surgeons and institutions. Draping should be wide enough to permit a posterolateral thoracotomy.

General Considerations:

General guidelines to follow include:

1) Avoiding traction or pressure on the pulmonary artery and its branches (the veins and bronchi are more forgiving)
2) Dissecting away the visceral pleura from the hilum both anteriorly and posteriorly prior to isolating the various structures
3) Being acutely aware of the stapler and the position of its jaws as you manipulate it in the chest
4) removing lymph nodes as the dissection proceeds to help improve visualization
5) Clarifying the anatomy prior to dividing any structures

Some surgeons routinely clamp the bronchus and have the anesthesiologist insufflate the remaining lung to confirm its identity prior to dividing. Check to make sure any suction catheters are removed from the airway prior to stapling. Rapid or uncontrollable bleeding requires conversion to thoracotomy. The assistant should hold pressure to tamponade the bleeding while the surgeon rapidly performs a thoracotomy, and the anesthesiologists resuscitate the patient.

Stapler failures are rare but catastrophic. After firing a stapler, carefully move it away from the hilum prior to removing it from the chest, to avoid tearing vascular structures. Oozing from the stapler line usually ceases with time, pressure, and topical hemostatic such as Surgicel ®; if not, a clip can be deployed. The typical order of division of structures listed in the sections on specific lobectomies is summarized in Table 1, though it may vary depending on the surgeon and the anatomy of each individual patient. If performed for cancer, each lobectomy should be followed by mediastinal lymph node dissection, which is described in the following section after the descriptions of the lobectomies.

Right Upper Lobectomy:
The lobe is visualized from the anterior side, with the right upper and middle lobes retracted so that the veins are oriented vertically in the field. The lobectomy usually begins by identifying the RUL and pulmonary vein branches, followed by transection of the RUL vein branch. This uncovers the truncus branch of the pulmonary artery (PA) going to the anterior and apical segments of the RUL, which is then isolated and divided. At that point, the RUL bronchus usually comes into view and is then divided. The posterior ascending branch of the PA is behind the RUL bronchus and is therefore the last hilar structure to be divided (be wary of a possible additional posterior branch). Identify the branch from the PA to the superior segment of the RLL to avoid stapling this prior to dividing the minor fissure, which is the final step in the resection.

Right Middle Lobectomy:
The utility port may be placed in a lower interspace than standard for this lobectomy to provide more room to work. Part of the major and/or minor fissure may need to be divided first to allow for exposure of the hilum. The inferior and superior pulmonary veins are identified. The RML vein is distinguished from the RUL vein and is divided. This reveals the RML bronchus, which is then transected. Finally, the RML artery/arteries are divided (there may be 1 or 2). Division of the major and minor fissures is then completed with the stapler, taking care to avoid the superior segmental artery to the RLL (located in the major fissure) and venous branches to the RUL (located in the minor fissure).

Left Upper Lobectomy
The order in which structures are divided in the left upper lobectomy is more variable than the other lobectomies, which reflects the greater anatomical variability of this lobe in terms of the number of arterial branches. The left superior pulmonary vein is usually the first structure to be taken during this operation. Prior to transecting it, the inferior pulmonary vein should be located to avoid inadvertently dividing a misidentified "common vein" that bifurcates into the superior and inferior veins outside of the pericardium.

After the vein is divided, the left upper lobe bronchus should come into view, behind which is the PA and its branches. Dissecting out the LUL bronchus will reveal the anterior segmental artery. Either the bronchus or anterior segmental artery may be divided first, in whichever order is more anatomically favorable. The apicoposterior segmental artery/arteries begin to come into view after dividing the anterior segmental artery and can be divided at this point if convenient.

After the LUL bronchus is divided, the lingular artery/arteries are visualized and divided, along with the apicoposterior segmental arteries if they have not already been divided. Identify and avoid the superior segmental artery of the LLL prior to doing so. Finally, the fissure is divided.

Left/Right Lower Lobectomy:
The incision on a lower lobectomy will usually be slightly larger than that of an upper lobectomy, as a lower lobe requires more space to be extracted through the chest wall. The order of division of structures may vary depending on the surgeon; here we present a caudal-to-cranial approach. First, divide the inferior pulmonary ligament and remove the level 9 lymph node, if present. Then isolate the inferior pulmonary vein and transect it. Again, it is necessary to visualize the superior pulmonary vein prior to doing so, to avoid a catastrophic misidentification.

Next, the lower lobe bronchus comes into view; it should be dissected free and divided. Note that the pulmonary artery will be immediately behind the bronchus. The ongoing pulmonary artery is then encircled and transected, taking care to first identify and avoid the branch(es) to the lingula (or right middle lobe if doing a right lower lobectomy). Finally, the fissure is divided. If the major fissure is well developed, it may be easiest to divide it completely and then isolate the ongoing pulmonary artery first.

Postoperative Considerations:
For resections on the right that do not include removal of the middle lobe, it is imperative that the middle lobe is visualized during re-expansion of the lung to ensure that torsion has not occurred. Appearance of torsion on a postoperative CXR warrants immediate bronchoscopy. If bronchoscopy confirms the diagnosis, immediate return to the operating room is indicated. The usual management of torsion is lobectomy, as detorsion of an infarcted lobe can lead to massive release of cytokines, resulting in hemodynamic instability and possible death.

Standard postoperative management includes placement of chest tubes at the end of case under direct visualization with placement on suction. IV fluids are minimized. Early ambulation and pulmonary toilet (coughing, nebulizers, incentive spirometry) are emphasized.

Besides either an epidural or regular PCA, lidocaine patches and standing acetaminophen are given in the absence of contraindications. Anti-inflammatories such as ketorolac should be given with caution, as the age and relative hypovolemia of these patients in the perioperative period predispose them to acute kidney injury. DVT prophylaxis is given.

For lobectomies, chest tubes are generally removed on postoperative day 1-2 in the absence of air leak, as long as the amount and quality of chest tube drainage is reasonable. If the patient has an epidural this can also be removed on postoperative day 2 typically; a foley is not required to be in place for the entire duration of the epidural and can be removed when appropriate.

Anti-hypertensives with the exception of beta-blockers are generally held if patients have an epidural in place due to the risk of hypotension. Hypotension in the presence of an epidural is treated with decreasing, changing, or discontinuing the epidural infusion in addition to judicious fluid administration. Use of a low dose vasoconstrictor rather than large amounts of IV fluid is generally preferable.

Awake bronchoscopy is indicated if the patient's oxygen requirements are increasing, pulmonary toilet is suboptimal, or if there is radiologic evidence of lobar collapse. Prolonged air leaks are managed non-operatively in most cases. Atrial fibrillation prophylaxis is usually not given for lobectomies.

Note on Robotics

The robotic approach for VATS is becoming increasingly common with equivalent perioperative outcomes to traditional VATS approaches. The pre-operative and post-operative considerations are largely the same as for VATS; additional considerations include availability of the equipment (robotic system, possibly the paired operating room table, replacement tools), nursing staff trained in robotics equipment, a first assistant trained in robotic surgery, and support from industry. After positioning the patient, trochars are inserted similarly to the VATS approach; Figure 1 for robotic port placements. Next, the robotic arm for the camera is docked, the camera is then inserted, (if targeting is performed the target typically is on the hilum), and the remainder of the arms are docked. The operations proceed as described previously with modifications based on the robotic tools. At the conclusion of the operation, the assistant typically undocks one arm and inserts the chest tube.

Advantages of robotics are 3D high-definition view, more natural wrist motion compared to VATS, and ability to adjust the operator console ergonomics for each surgeon. The disadvantages include lack of haptic feedback, the high cost, equipment, and resources required.

Mediastinal Lymph Node Dissection

Overview:
To review, mediastinal lymph node stations are numbered 1-9 (single digits), while those outside the mediastinum are 10 and greater. Mediastinal lymph nodes accessible from the right side thoracoscopically include 2R, 4R, 7, 8, and 9. Mediastinal lymph nodes accessible from the left side thoracoscopically include 5, 6, 7, 8, and 9.

If a prior mediastinoscopy has been performed, there may be scarring (if the procedure was several days to weeks ago), hematoma (if it immediately precedes thoracoscopy), and/or fewer remaining paratracheal lymph nodes (stations 2 and 4) to be sampled.

Right Thoracoscopic:
When performing a paratracheal lymph node dissection (2R, 4R) from the right, the goal is to clear the space between the azygos posteriorly, the innominate vein/SVC anteriorly, and the innominate artery superiorly. The "floor" of the dissection is the pericardium/trachea. The recurrent laryngeal nerve is not often located within this space so would be uncommon to find during this dissection; the nerve typically wraps around the subclavian artery, which is more superior than the typical dissection location.

Retract the upper lobe posteriorly and inferiorly, if not already removed. The paratracheal lymph nodes can be accessed either from above or below the inflow of the azygos vein into the innominate vein. Open the pleura and while retracting the pleura upward (and azygos vein, if approaching from below the inflow), bluntly dissect out this space. To perform a complete lymph node dissection, remove enough mediastinal lymph node tissue and accompanying fat until you can clearly see the boundaries described previously.

In order to remove level 7 (carinal) lymph nodes, retract the remaining lobe(s) of the lung anteriorly (Figure 3), and identify the bronchus intermedius. Follow this structure proximally to reach the carina. Open the pleura in this space, and bluntly dissect this window until you have identified and removed the level 7 lymph node. The esophagus will be located posteriorly and generally does not have to be manipulated during this dissection.

To remove the level 9 (inferior pulmonary ligament) lymph node, divide the inferior pulmonary ligament with electrocautery while retracting the lung superiorly and anteriorly. Stay near the parenchyma of the lung. Be cognizant of the inferior pulmonary vein, which will be running just superior to this ligament. Level 9 lymph nodes are encountered within the ligament. This portion of mediastinal lymph node dissection is often performed early on during lobectomy while the lung is being mobilized.

Left Thoracoscopic
The paratracheal lymph nodes (2L, 4L) are not typically accessed from the left because the aorta obstructs access to the trachea. Lymph nodes at stations 5 (aortopulmonary window) and 6 (paraaortic) are accessible from the left. Identify the main trunk of the left pulmonary artery and open the pleura just superior to it. While retracting the pleura with a toothed grasper, used an empty curved forceps or similar instrument to bluntly dissect out the aortopulmonary window. Remove any lymph nodes located here. The recurrent laryngeal nerve will be located in this space so avoid cautery; grasp lymph node tissue and try to dissect away surrounding lymphovascular structures instead of performing blind exploration/resection. The dissection can be extended to the para-aortic region in order to obtain level 6 lymph nodes, although this is not typically done during lung cancer surgery unless there is a specific indication to do so.

Level 7 lymph nodes are more difficult to remove from the left side because the carina is located towards the right. Retract the lung anteriorly and identify the left main stem bronchus (if you have performed a lower lobectomy) or the left lower lobe bronchus (if you have performed an upper lobectomy). Open the pleura here and dissect out the space beneath the bronchus bluntly. The esophagus often needs to be retracted posteriorly (towards the aorta) to locate level 7.

Removing the level 9 lymph node is identical to the procedure described previously in the "Right Thoracoscopic" section.

Table 1: Summary of Common Order of Key Structure Division for Lung Lobectomy

Figure 1: Robotic Port Locations

Note: All ports in 8^th intercostal space with assist port placed approximately 2 intercostal spaces lower.

(Image used with permission of Dr. Samuel Kim, Canning Thoracic Institute, Department of Surgery, Northwestern University Feinberg School of Medicine)

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