Technique of right sided mediastinal node dissection

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Mediastinal node dissection technique- right side:

Following the appropriate pulmonary resection, all lymph nodes in the right side of the mediastinum are systematically dissected.

In this illustration, the dissection is started at the diaphragm. The inferior pulmonary ligament is excised and the mediastinal pleura extending from the pericardium back to the spine is excised as well as the lymph nodes lying anterior to the esophagus. Care is taken to clip all tissues at the inferior margin of the dissection to avoid lymphatic leaks. Injury to the esophagus and vagus nerve branches is carefully avoided.

Nodal tissue in this area incorporates lymph nodal areas 8 and 9 and is so marked and packaged for pathologic examination.

The extent of this dissection is from the diaphragm to the subcarinal space.

The subcarinal space is the most difficult part of the proceedure. The remaining right lung must be gently retracted forward, being careful of hemodynamic effects and avoiding displacement of a right Univent blocker balloon, if one has been used.

This dissection incorporates all of the lymph nodes along the back wall of the right main bronchus and extends to the carina and on to the origin and first few centimeters of the left main bronchus. Technique must vary according to the consistency of the nodes. If the nodes are soft and friable, they are best dissected with a Kittner "peanut" dissector. If firm, the nodes can be retracted upward with a pickup and dissected with a scissor or electrocautery.

It is important to be on the watch for a bronchial artery traversing the space. It can be surprisingly large, and tends to retract back deeply into the mediastinum if transected before gaining control. It should be carefully clipped and/or coagulated.

The specimen consists of nodes from group 7 and should be separately labeled as such for the pathologist.

The upper mediastinal dissection begins with dissection, and ligation of the azygos vein anteriorly at the superior vena cava, and posteriorly. After doubly securing this large vein at each end with large clips, it is transected. Some surgeons mobilize but do not transect the vein. I have tried this, but find that the disection of the precarinal area is more difficult under these circumstances.

Next, two longitudinal incisions are made in the parietal pleura, the first follows the course of the vagus nerve and the second, the posterior edge of the superior vena cava. The incisions meet over the brachiocephalic artery.

Anterior traction on the ligature on the azygos vein and a separate vein retractor allow dissection of all tissues off the posterior wall of the superior vena cava.

Although not mentioned in anatomy books, small venous branches enter the SVC in a small percentage of cases. They should be watched for and clipped.

The dissection continues medially to the ascending aorta, carefully avoiding injury to the contralateral recurrent nerve.

After the vagus nerve is dissected, all pretracheal and right paratracheal lymph noded are encircled by finger dissection and a loop is passed around this tissue for traction. Blunt finger dissection continues inferiorly in the precarinal space, and all nodal tissue is teased up off the right pulmonary artery.

The lower dissection is completed by clipping the inferior margin of the dissected tissues

Tissues at the upper margin of dissection are clipped or cauterized and divided.

As the uppermost tissues of the dissection are reached, the tissue is clamped with a right angle clamp, the specimen excised and the tissue ligated.
The completed dissection, shown here incorporates all tissue behind the SVC, to the right of the ascending aorta and in front of the trachea, and extends from the brachiocephalic artery to the right pulmonary artery and azygos vein.

Nodes from the brachiocephalic artery are labeled 2, and constitute the upper margin of the dissected specimen. The remainder of the specimen is labeled 3 and 4.

If there are enlarged nodes palpable anterior to the phrenic nerve, the nerve is retracted with a tape and the nodes dissected.

Surgicel gauze is gently packed into the space created behind the SVC and into the subcarinal space to aid in hemostasis.

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