Technique and Application of Transcervical Extended Mediastinal Lymphadenectomy in Thoracic Surgery

The position of the operating team is shown in Fig. 2. Generally, TEMLA can be performed with two surgeons and one scrub nurse. The surgeon stands behind the patient's head and the assistant and scrub nurse stand to the patient's right side. In some exceptionally difficult cases or for surgeons who are only beginning to perform TEMLA, having the second assistant standing on the left side of the patient may be helpful. We prefer to perform the operation with the use of electrosurgical coagulation or harmonic scalpel. However, it is also possible to achieve hemostasis with the use of vascular clips. Generally, TEMLA is an open procedure that is performed under direct eye control with the use of normal surgical instruments developed for open surgical procedures.

The operation is performed through a collar incision in the neck just above the sternal notch. The length of incision is 5 to 8 cm. The platysma muscle is divided and the anterior jugular veins are exposed, suture-ligated, and divided. Bilateral visualization and protection of the laryngeal recurrent nerves are priorities. The technique used for visualization of the laryngeal recurrent nerves is described elsewhere in the article. In short, to reach the nerve below the level of the thyroid gland, one must divide the deep cervical fascial layers covering the carotid arteries until the clean wall of the artery is reached. Traction is then applied on the carotid artery in the lateral direction and in the opposite direction on the trachea. This maneuver stretches the tissue between these structures containing the laryngeal recurrent nerves. With use of a blunt dissection with a peanut sponge, the laryngeal recurrent nerves can be safely visualized almost instantly. The key is not to dissect the nerve circumferentially and to leave the deepest layer of the fascial tissue covering the nerve. These maneuvers protect the nerve from injury. The right recurrent nerve runs from the division of the innominate artery to the larynx (Fig. 3). The left laryngeal recurrent nerve lies in the groove between the trachea and the esophagus (Fig. 4). The position of both nerves is almost always constant that we have never seen any anatomical variability of their position in more than 1200 operations with the laryngeal recurrent nerve dissection (including TEMLA, transcervical-subxiphoid-VATS maximal thymectomies, the resection of the various mediastinal lesions, and the esophageal resections).

After visualizing both laryngeal recurrent nerves, the sternal manubrium is elevated with a sharp three-teeth hook connected to the Rochard frame (Aesculap-Chifa Co., Nowy Tomysl, Poland) to widen the access to the mediastinum.

The highest mediastinal nodes (station 1) are dissected first. These nodes are located above the upper margin of the left innominate vein and belong to the anterior lymphatic flow from the chest. The fatty tissue containing these nodes is dissected from the right carotid artery and the right innominate veins (laterally, on the right side), from the left carotid artery (laterally, on the left side), and then is dissected from the trachea (posteriorly) and from the left innominate vein (inferiorly). The piece of tissue containing the station 1 nodes is resected en bloc along with the upper poles of the thymus gland.

Entering the right paratracheal space containing stations 2R and 4R is done by dissecting along the right vagus nerve, which is located between the right carotid artery and the right jugular vein (Fig. 5). The dissection proceeds along the nerve, below the division of the innominate artery. The origin of the right laryngeal recurrent nerve is clearly visible and protected from injury. Dissection proceeds toward the tracheal bifurcation. All the fatty tissue containing the 2R and 4R nodes lying between the right innominate vein and the right mediastinal pleura (laterally), the ascending aorta and trachea (medially), the back wall of the superior vena cava (anteriorly), the esophagus and the thoracic spine (posteriorly), the right main bronchus, the azygos vein, and the right pulmonary artery (inferiorly) is removed. Any vessels in this area can be handled with vascular clips, electrosurgical coagulation, harmonic knife, or cautery (Fig. 6).

The next step is to dissect the left paratracheal space. By retracting the trachea to the right side and the left common carotid artery to the left and upwards, this enables excellent visualization of the entire left paratracheal space to the proximal one-third of the left mainstem bronchus. The dissection proceeds along the left laryngeal recurrent nerve below the level of the tracheal bifurcation. The nerve is dissected from the left wall of the trachea and the left main bronchus with a peanut sponge, while lateral connections of the nerve are preserved to maintain the blood supply. Division of the fascial layer covering the nerve is usually necessary to visualize the nerve. In most patients, the left upper paratracheal nodes (station 2L) are located medially and in front of the nerve, while the lower paratracheal nodes (station 4L) almost always lie behind it (Fig. 7). Carefully preserving the left laryngeal recurrent nerve, the lymph nodes 2L and 4L are dissected. Our current practice is to dissect the most distal 4L nodes with the aid of a mediastinoscope. We have found that it is also helpful in removal of the most distal lower paratracheal nodes (station 4L) in some patients, reaching the division of the left main stem bronchus. In these patients, removal of the lower paratracheal nodes (station 4L) is postponed until the subcarinal and the periesophageal nodes are removed.

To enter the subcarinal nodes, it is necessary to divide the firm fascial layer covering the station 7 nodes anteriorly. Dissection proceeds along the medial walls of both main bronchi for 4 to 5 cm. The package containing the station 7 and 8 nodes is dissected from the pulmonary artery, the pericardium covering the left atrium (anteriorly), and the esophagus (posteriorly) and is then removed en-bloc (Fig. 8). For the removal of the subcarinal and periesophageal nodes (stations 7 and 8), a mediastinoscope is used; we prefer to use the operative Linder-Dahan videomediastinoscope (Richard Wolf GmbH, Knittlingen, Germany), which is equipped with moving blades that are very useful in retracting the pulmonary artery from the carina during dissection of node station 7, and the left atrium from the esophagus during dissection of node station 8, to 5 to 8 cm below the carina. The mediastinoscope is used for retracting these structures and for visualization only. Removal of lymph nodes is performed using a standard dissector for open surgery, introduced through the right paratracheal space along the mediastinoscope.

The entrance to the aorta-pulmonary window and station 6 nodes lies between the left innominate vein and the left carotid artery. The first step in reaching this area is to divide the firm layer of the fascial tissue between the innominate artery, the left carotid artery, and the left innominate vein (Fig. 9). The fascial layer obscures the view of these vessels and, after its division, the left innominate vein can be retracted anteriorly. After retracting the vein upwards by using a long retractor, the plane is developed at the anterior surface of the aortic arch. With blunt dissection using a peanut sponge, the fatty tissue containing the station 6 nodes is dissected of the ascending aorta until the left pulmonary artery is reached. The left vagus nerve is a landmark of dissection. The nodes located above the convexity of the aortic arch and lying in front of the vagus nerve cross the aortic arch and the Botallo ligament and the para-aortic nodes (station 6). The nodes are located below the aortic arch and behind the Botallo ligament and the pulmonary-window nodes (station 5). Left pulmonary artery, the left phrenic nerve, and the left superior pulmonary vein are well visible after completion of dissection (Fig. 10). In case the mediastinal pleura opens, there is no need to drain the mediastinum. Inserting a piece of fibrin sponge and hyperinflating the lungs during closure of the wound is all that is necessary in such cases. The same rule is valid if the mediastinal pleura is opened on the right side.

Stations 3A (prevascular nodes) and 3P (retrotracheal nodes) are removed in selected patients. Station 3A nodes lie below the left innominate vein, in front of the superior vena cava, medially to the right mediastinal pleura, and laterally to the ascending aorta. These nodes are dissected after removal of station 1 nodes. The left innominate vein and the superior vena cava are retracted posteriorly with a peanut sponge and the fatty tissue containing the 3A nodes is dissected from the structures mentioned above (Fig. 11). In our experience, these nodes are rarely the site of metastasis in the case of the right-sided tumors.

The retrotracheal nodes (station 3P) are located behind the bifurcation of the trachea. This area is approached in same fashion as the right paratracheal nodes. The tracheal bifurcation is retracted anteriorly, which enables the visualization of the nodes lying in front of the esophagus. The nodes are easily removed; however, we never found any metastatic nodes in this station and most often there are no visible nodes in this location at all.

During TEMLA, all mediastinal lymph nodal stations and the surrounding fatty tissue are removed with the exception of the pulmonary ligament, station 9 nodes.

We try to follow the rule of performing lymphadenectomy in en-bloc fashion, at least in part, with resection of the whole package of the lymphatic tissue without separation of the individual nodes. It is possible to remove all the nodes of station 1 in one piece containing also the upper poles of the thymus. Afterward, stations 2R and 4R are removed in one piece; the same is done for stations 7 and 8 and 5 and 6. We remove the nodes of stations 2L and 4L separately because they almost never occur in one piece of tissue.

Generally, TEMLA is an open procedure, with the exception of dissection of the subcarinal (station 7), the periesophageal (station 8) nodes, and the left lower paratracheal (station 4L) nodes, which are dissected in the mediastinoscopy-assisted fashion with the aid of Linder-Dahan two-blade mediastinoscope. The para-aortic, station 6 and aorta-pulmonary window, station 5 nodes are sometimes dissected with the aid of videothoracoscope introduced to the mediastinum through the operative wound.

Bilateral supraclavicular lymphadenectomy and even deep cervical lymph node dissection is possible during TEMLA through the same incision, although we do not recommend this addition for routine use for NSCLC.