Master Techniques in Surgery: Thoracic Surgery: Lung Resections, Bronchoplasty, 1st Ed.

7. Robotic Lymph Node Dissection

Franca M. A. Melfi, Olivia Fanucchi, and Alfredo Mussi

 INDICATIONS/CONTRAINDICATIONS

Definition

“Robotic surgery” is an imprecise term, but it has been widely used by both the medical and lay press and is now generally accepted. The term refers to the surgical technology that places a computer-assisted electromechanical device in the path between the surgeon and the patient. A more scientifically accurate term would be “remote tele-presence manipulators” since the available technology does not generally function without the explicit and direct control of a human operator. For the purposes of the document, we define robotic surgery as a surgical procedure or technology that adds a computer technology enhanced device to the interaction between the surgeon and the patient in a surgical operation and assumes a certain degree of control heretofore completely reserved to the surgeon.

Indication

Robotic lobectomy is commonly performed in selected peripheral located T1 or T2 tumors and usually reserved to patients where complications are not expected. However, during these past years, robotic technology was applied also in central tumors, pneumonectomy, and in sleeve lobectomies. With regard to lymph nodes staging of NSCLC during surgical intervention, it should be as accurate as possible, however, the extent of mediastinal lymph nodes’ assessment is still a debated issue. In fact several approaches are utilized, ranging from simple visual inspection of the unopened mediastinum to an extended bilateral lymph nodes’ dissection. However, ESTS guidelines recommended systematic nodal sampling or dissection with the removal of at least six lymph nodes (UICC) from hilar and mediastinal stations to define pathologic N0.

Contraindication

The principal contraindications for the robotic approach are related to the presence of tenacious pleural adhesions, which can be expected when the medical history shows previous pleuritis, chest radiation therapy, or previous thoracic intervention. In addition, large tumors (greater than 5 to 6 cm) are contraindicated in a minimally invasive approach due to the limited maneuverability of the lesion itself in a close chest setting.

 PREOPERATIVE PLANNING

Patient’s evaluation should be based on a chest x-ray, chest and upper abdomen CT scan imaging with contrast media enhancement, and positron emission tomography (PET) scan. Invasive staging procedures, such as mediastinoscopy, can be omitted in patients with stage I NSCLC and negative PET scan, while in central tumors, PET hilar N1 disease, low FDG uptake of the primary tumor and LNs ≥16 mm on CT, invasive staging remains indicated, according to ESTS guidelines. PET positive mediastinal findings should be histologically or cytologically confirmed.

Preoperative functional assessment consisted of medical history, physical examination, routine blood tests, blood gas analysis, spirometry, and cardiologic evaluation with electrocardiogram and echocardiography. Stress testing and other assessments of myocardial function were performed when indicated by the cardiologist in case of a history of coronary artery disease, suspicious symptoms, or electrocardiographic abnormality.

 SURGERY

Robotic System

The robotic system consists of a master remote console, a computer controller, and a manipulator with fixed remote center kinematics connected via electrical cables and optical fibers. The master console is connected to the surgical manipulator with the camera arm and three instrumental arms. The surgeon manipulates two master handles and the movements are transmitted to the tips of the instruments, thanks to the highly sensitive motion trigger sensor. The surgical arm cart provides three degrees of freedom (pitch, yaw, and insertion), while the tips of the instruments are characterized by a mechanical cable-driven wrist (EndoWrist), providing four more degrees of freedom (internal pitch, internal yaw, rotation, and grip).

This system overcomes many of the technical obstacles found in the traditional thoracoscopic surgery.

 The robotic system provides stereoscopic binocular vision allowing a depth perception and optical resolution to the surgeon.

 Stable camera holders are one of the benefits of robotic system. The scope is held by the central arm, which is directly and optimally controlled by the surgeon at the console, permitting both an increased close vision for fine dissection and a panoramic vision of the whole thoracic cavity. In addition, the robotic camera holder liberates the assistant’s hands, allowing him/her to perform other functions.

 Magnified video imaging up to 10 times the actual size.

 Robotic instruments reproduce the human hand’s degrees of freedom, inside chest cavity (internal pitch, internal yaw, rotation, and grip).

 Downscaling of surgeon’s movements, in fact the robotic system is a transducer of surgeon’s movements in more fine ones of the instrument tips.

 Tremor filter: The robotic system software is able to filter up to 6 Hz of the surgeon’s hand tremor due to a transducer that is able to reproduce only the desired movements in the operative field.

Patient Positioning and Port Mapping

General anesthesia with double-lumen intubation is mandatory. The patient is positioned in a lateral decubitus position, such as for a poster lateral thoracotomy, with the operating table flexed at the scapula tip level. In case of female patients, a pillow can be positioned under the hip to have the patient’s hip and scapula leveled on the same line. The appropriate sites of the incisions are essential for the success of the procedure, and to avoid any arm impingement during the operation. For this reason a minimum distance of 6 to 8 cm from each arm is required. Generally, the first port is placed in the seventh to eighth intercostal space on the midaxillary line. In this site the camera (12 mm, 30-degree angled down scope) is positioned (called camera arm). Then, an exploration of the chest cavity is performed by the camera to have important information that could alter the programed procedure. Following, the other port incisions (8 mm) can be performed: Sixth to seventh intercostal space on the posterior axillary line (first arm), fourth to fifth intercostal space on the anterior axillary line (second arm), and in the auscultatory area (for the third arm). However, the port mapping can vary, and the best port positioning is assessed during chest cavity exploration, in relation to the fissure and to the shape of each patient’s thorax. A utility port between the camera port and the anterior robotic port can be positioned for the assistant surgeon, who has to introduce the stapler or suction. Only in some difficult cases, a service entrance, with rib spearing, can be performed. Since September 2010, we are performing a totally endoscopic procedure, without service entrance. Although, at the beginning, during the learning curve, a utility incision is recommended. Subsequently, with gained experience, it is possible to utilize a totally endoscopic technique.

Surgical Cart Positioning

After the port incisions are performed, the surgical cart can be positioned from the head of the patients. The center of the column of the surgical cart must be in line with the camera port and the longitudinal axis of the patient. This fact is mandatory to avoid impingements of the robotic arms. The layout is the same for the right and left side. Only when the patient has been placed in the chosen position and the surgical cart positioned appropriately, the ports can be fixed to the robotic arms. Thus the camera is inserted, then the instruments’ insertion in the chest cavity is accomplished under direct vision.

Instruments

On the right hand a hook or vessel sealer is generally used for dissection. On the left hand fenestrated forceps can be used for dissection and surrounding the hilar structures. The fourth arm is generally used for the retraction of the lung, thanks to a Prograsp forceps or robotic irrigator, to expose hilar structures. These are the robotic instruments currently available.

 Cadiere forceps

 Permanent cautery hook (monopolar cautery)

 Fenestrated forceps (bipolar cautery)

 Maryland (bipolar cautery)

 Prograsp forceps

 Vessel sealer (bipolar cautery)

 Robotic irrigator

Technique

The dissection of mediastinal lymph node follows the same steps as it does in open surgery. It is carried out with hook or vessel sealer on the right hand and fenestrated forceps on the left hand, to excise en-bloc the fatty tissue of the hilum and mediastinum that contain the lymph nodes. Attention must be taken to prevent damage to the lymph nodes and to dissect free the adipose tissue surrounding the lymph nodes themselves. It is necessary to coagulate small lymphatic channels with hook or better with vessel sealer to prevent bleeding or exudation of lymphatic fluid into the chest. A Cadiere is generally used on the left arm and a vessel sealer or a hook is used on the right arm. Suction/irrigator can be used on the third arm to keep the operative field clean.

Figure 7.1 Station 2 to 4: The mediastinal pleura is incised vertically from the apex along the edge of the superior vena cava. The vagus and phrenic nerves are identified and carefully preserved. When possible the fatty tissue, located between the superior vena cava, anteriorly, and the esophagus, posteriorly, should be removed as an en-bloc resection.

Before starting the surgical intervention, the pulmonary ligament is separated from the mediastinal pleura adjacent anteriorly and posteriorly to it. The number and consistency of lymph nodes have a high variability at any station: They can be absent, discrete, or copious and surrounded by abundant fat tissue. Mediastinal lymph node dissection is generally performed at the end of the procedure; however, the dissection of some lymph node stations is required during hilum dissection, to safely complete the lobectomy. For example, for the dissection of the Boyden artery, dissection of station 4 can be useful to obtain enough space for stapler positioning. However, here below, we have described the procedures station by station.

Right Side

Station 2 to 4: The mediastinal pleura is incised vertically from the apex along the edge of the superior vena cava. The vagus and phrenic nerves are identified and carefully preserved. When possible the fatty tissue, located between the superior vena cava, anteriorly, and the esophagus, posteriorly, should be removed as an en-bloc resection (Fig. 7.1). Generally the fatty tissue and lymph node are dissected away from the tracheal wall and the posterior wall of the superior vena cava, taking particular attention on identifying eventual intercostal veins that drain directly in superior vena cava. It is recommended to master these veins with a clip, because if accidently cut, they have a tendency to retract and disappear, making the control of bleeding difficult. Then the dissection continues down to station 4. The division of the azygos vein is not necessary: The wristed instrumentation allows to safely reach the fatty tissue behind the vein, and if needed the azygos vein can be surrounded by a sling and retracted.

Station 3: Once the upper mediastinal pleura is opened, the lymph nodes in front of the superior vena cava and/or posterior to the trachea are accessible. Generally, this station is dissected in continuity with station 2.

Station 7: The lung is retracted anteriorly to expose the posterior face of the hilum. The pleura is incised posteriorly to the hilar structures, to expose the bifurcation of the trachea. The dissection of the subcarinal lymph node is performed, and when necessary it can be en-bloc with the main right bronchial stem or the right upper lobe bronchial lymph nodes. It is readily seen during dissection that these lymph nodes are in direct continuity with each other (Fig. 7.2).

Figure 7.2 Station 7: The lung is retracted anteriorly to expose the posterior face of the hilum. The pleura is incised posteriorly to the hilar structures, to expose the bifurcation of the trachea. The dissection of the subcarinal lymph node is performed, and when necessary it can be en-bloc with the main right bronchial stem or the right upper lobe bronchial lymph nodes.

Station 8: Once the pleura is opened, the esophagus is exposed. The paraesophageal fatty tissue is removed, taking particular attention not to damage the vagus nerve. Generally, the dissection of these lymph nodes is performed in continuity with those of pulmonary ligament.

Station 9: The lower lobe is retracted upward with the third arm, to expose the pulmonary ligament. Then the mediastinal pleura is incised anteriorly and posteriorly to the pulmonary ligament, with the hook or vessel sealer, until the inferior pulmonary vein is identified. Thus, the fatty tissue with the lymph nodes is dissected. In case of a lower lobectomy, these lymph nodes are often removed with the specimen (Fig. 7.3).

Left Side

Station 3 to 4: The upper lobe is down retracted, generally with the right hand (first arm). To expose station 3 lymph nodes, the pulmonary artery is dissected from the main bronchus to identify the trachea. Nodal tissue is removed with a Cadiere on the left hand (second arm) and a hook or a vessel sealer on the right arm (fourth arm).

Figure 7.3 Station 9: The lower lobe is retracted upward with the third arm, to expose the pulmonary ligament. Then the mediastinal pleura is incised anteriorly and posteriorly to the pulmonary ligament, with the hook or vessel sealer, until the inferior pulmonary vein is identified. Thus, the fatty tissue with the lymph nodes is dissected. In case of a lower lobectomy, these lymph nodes are often removed with the specimen.

Figure 7.4 Station 5 to 6: The upper lobe is down-retracted. The mediastinal pleura is incised at the level of the pulmonary artery and continued upward at the left side of the vagus nerve, which must be identified and preserved.

Station 5 to 6: The upper lobe is down retracted. The mediastinal pleura is incised at the level of the pulmonary artery and continued upward at the left side of the vagus nerve, which must be identified and preserved. Once the pleura is opened the Botallo ligament can be divided to reach the para-aortic and subaortic lymph node easily, which are generally resected en-bloc (Fig. 7.4).

Station 7: The lung is retracted anteriorly (third arm) to expose the hilum and the descending aorta. The mediastinal pleura is opened proximally to the hilum to preserve the vagus nerve and the laryngeal recurrent nerve that surround the aorta below its concavity. There are bronchial arteries that regularly arise from descending aorta. These should be identified and coagulated. Then the left main bronchus is identified and followed proximally, thus the subcarinal space is reached, with gentle retraction of the esophagus posteriorly. Dissection is performed taking special attention not to injure the esophagus or the membranous parts of the bronchus.

Station 8: Generally, this station is explored after the division of the pulmonary ligament. The lower lobe is retracted upward (third arm). Thus the medial mediastinal pleura is opened to expose the paraesophageal lymph nodes, taking attention not to injure the esophagus or vagus nerve.

Station 9: The lower lobe is retracted upward with the third arm, to expose the pulmonary ligament. Then the mediastinal pleura is incised anteriorly and posteriorly to the pulmonary ligament, with the hook or vessel sealer, until the inferior pulmonary vein is identified. Thus, the fatty tissue with the lymph nodes is dissected.

 POSTOPERATIVE MANAGEMENT

Two chest tubes (28 F and 32 F) are positioned into the anterior port and the camera port, respectively, and connected to a pleurovac. Then the lung is gently expanded and the other ports are closed. The patient is awaken and goes to a subintensive care unit. A chest x-ray is performed in the operative day. Intravenous fluid administration with an isotonic solution for the first 24 hours will maintain a normal intravascular volume. Intravenous antibiotics (large spectrum cephalosporin) together with gastroprotectants are administered postoperatively for 2 to 3 days, then they are administrated per os. Urine output may be a useful guide to evaluate the patient’s volume status in the first day or two postoperatively; thereafter, the catheter is removed.

No epidural anesthesia is required. However, even if it is a minimally invasive approach, an adequate pain control is important during the postoperative period to permit a proper breathing. Generally pain is controlled with intravenous infusion of FANS (diclofenac or similar) and tramadol for the first 24/48 hours. The patients are moved to the ward, generally in the first postoperative day and can walk autonomously in the second postoperative day. The chest drainage is removed when the eventual air leaking has stopped.

 COMPLICATIONS

Perioperative complications related to lymph node dissection are represented by vessel injury, recurrent laryngeal nerve injury, vagal injury, chylothorax, and airways injury. Vessel injuries can occur intraoperatively, above all during the dissection of hilar lymph nodes, which can be necessary to isolate hilar structures (bronchus, arterial branches, or vein). This adverse event is one of the most frequent causes (together with oncologic ones) of conversion to open surgery. In this case, it is recommended to compress the damaged vessel with a pad, thus allowing to promptly perform a thoracotomy.

Recurrent nerve injury generally can occur on the left side, during the dissection of station 5 to 6, due to its anatomy: It originates from the vagus nerve and goes upward surrounding the aortic arch. It is important that the incision of the mediastinal pleura is done proximally, near the hilum to preserve the recurrent nerve. Vagal nerve injuries are less frequent because it can be easily identified during the dissection of station 7 and 8, once the mediastinal pleura is opened.

Chylothorax is observed when the patient is allowed a regular diet, but often a latent interval of 2 to 10 days passes between the time of the injury and its clinical evidence. There is a large variability in the course of the thoracic duct, which generally crosses from the right side to the left side, at the level of the fifth to sixth thoracic vertebrae, and continues upward close to the left side of the esophagus and the pleural reflection, into the neck. Thus, injuries of thoracic duct can occur both from the left and right side, and are more frequent during the dissection of station 2 and station 4 to 7, respectively. With regard to the airway injuries, they generally interest the membranous part of the trachea, during dissection of station 2 to 4, or main bronchi, during the dissection of station 7 both for the left and the right side. Table 7.1reports the most common adversities.

 RESULTS

Many studies were published demonstrating the safety and the feasibility of different robotic techniques for lung lobectomy in case of early stage NSCLC. However, the debate about the adequacy of robotic lymph node dissection is still open. Some recent studies compared robotic and thoracotomic mediastinal lymph node dissection for early stage NSCLC. They verified equivalence between robotic and open approaches, both for total number of resected lymph node, and the median number of N1 and N2 lymph node stations assessed (Table 7.2). In addition, it should be recognized that robotics, thanks to its three-dimensional vision and to the articulation of the instruments, allow greater confidence in dissecting N1 lymph nodes adjacent to the lobar arteries and bronchus. This may ultimately have an impact on oncologic outcomes in the long term, but in the immediacy of the operation it permits easier and safer passage of the stapler.

From an oncologic point of view, further studies are expected because there is only one paper reporting long-term survival. They obtained a 5-year overall survival of 80% with a median follow-up of 27 months, it increases up to 91% and 88% if stage IA and IB, respectively, were considered.

TABLE 7.1 Postoperative Results of Robotic Lobectomy

TABLE 7.2 Analysis of Number of Lymph Node and Lymph Node Stations Removed, and Survival Data

 CONCLUSIONS

Robotic lobectomy for NSCLC, maintaining the oncologic principles, represents an advantage for patients, offering less trauma and faster recovery. Although the current technique is still evolving, the current literature and our experience showed that the patients’ position and the site of port accesses are essential for the success of the intervention. From the oncologic point of view, large comparative studies with long follow-up are necessary.

Recommended References and Readings

Augustin F, Bodner J, Wykypiel H, et al. Initial experience with robotic lung lobectomy: Report of two different approaches. Surg Endosc. 2011;25:108–113.

Cerfolio RJ, Bryant BS, Skylizard L, et al. Initial consecutive experience of completely portal robotic pulmonary resection with 4 arms. J Thorac Cardiovasc Surg. 2011;142:740–746.

Gharagozloo F, Margolis M, Tempesta B, et al. Robot-assisted lobectomy for early-stage lung cancer: Report of 100 consecutive cases. Ann Thorac Surg. 2009;88:380–384.

Lardinois D, De Leyn P, Van Schil P, et al. ESTS guidelines for intraoperative lymph node staging in non-small cell lung cancer. Eur J Cardiothorac Surg. 2006;30(5):787–792.

Melfi FM, Ambrogi MC, Lucchi M, et al. Video robotic lobectomy. Multimed Man Cardiothorac Surg. 2005;2005(628):mmcts. 2004.000448.

Naruke T, Suemasu K, Ishikawa S. Lymph node mapping and curability of various levels of metastases in resected lung cancer. J Thorac Cardiovasc Surg. 1978;76:832–839.

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Park BJ, Flores RM, Rusch VW. Robotic assistance for video-assisted thoracic surgical lobectomy: Technique and initial results. J Thorac Cardiovasc Surg. 2006;131(1):54–59.

Park BJ, Melfi F, Mussi A, et al. Robotic lobectomy for non-small cell lung cancer (NSCLC): Long-term oncologic results. J Thorac Cardiovasc Surg. 2012;143:383–389.

Schmid T, Augustin F, Kainz G, et al. Hybrid video-assisted thoracic surgery-robotic minimally invasive right upper lobe sleeve lobectomy. Ann Thorac Surg. 2011;91(6):1961–1965.

Spaggiari L, Veronesi G, Kuenzer Caetano da Silva RF. Robotically assisted pneumonectomy for lung cancer. In: Inderbitzi RG, Schmid RA, Melfi FMA, et al., eds. Minimally Invasive Thoracic and Cardiac Surgery. Berlin, Heielberg: Springer-Verlag; 2012:161–172.

Veronesi G, Galetta D, Maisonneuve P, et al. Four-arm robotic lobectomy for the treatment of early-stage lung cancer. J Thorac Cardiovasc Surg. 2010;140:19–25.



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