Extended Cervical Mediastinoscopy 

Patient Selection 
Operative Steps 
Tips and Pitfalls 
Results 

Patient Selection

This technique, which explores the anterior mediastinum (Figure 1) in conjunction with a standard cervical mediastinoscopy, can be utilized to biopsy anterior mediastinal masses but is best employed to stage lymph nodes of the anterior mediastinum in conjunction with mediastinoscopy staging for lung cancer involving the left upper lobe (Figure 2).

Personally, I use this technique only when enlarged level 5 and/or level 6 nodes are evident on CT scan and the standard cervical mediastinoscopy fails to reveal involved superior mediastinal lymph nodes that would make the patient inoperable (Figure 3). The procedure should not be performed in patients with: 1) dilated aortic arch; 2) excessively calcified aortic arch; 3) previous sternotomy for cardiac disease (e.g., aortocoronary bypass). All of these conditions make exploration of the anterior mediastinum using this approach hazardous.

Operative Steps

Before beginning to use a procedure such as this, it is advised that a standard Chamberlain procedure be done in conjunction with the surgeon's first few attempts at using this technique to become familiar with it.

Following completion of the standard cervical mediastinoscopy, and if this proves to be negative for metastatic disease, the mediastinoscope is withdrawn from the cervical incision and the index finger is re-inserted into the mediastinum. The innominate artery is located, is palpated on its superior surface, and the index finger is then directed towards its origin from the aorta. Just to the left of the origin of innominate artery, the fascia investing the aortoinnominate junction is opened digitally (Figure 4). This opening is made between the innominate artery and the origin of the left carotid artery on the superior aspect of the aorta. This "window" is created posterior to the innominate vein although some authors have suggested an approach anterior to the innominate vein to reach the anterior mediastinal compartment and claim that it is just as effective.

Once the "window" in the fascia is created, the finger is withdrawn and the mediastinoscope is re-inserted through the cervical excision, directing it anterolaterally towards the left sternoclavicular junction. A blunt metal suction catheter is used to probe and identify the "window" created by finger dissection and the tip of the mediastinoscope is then gently "screwed" into the window, advancing it over the base of the innominate artery along the anterolateral surface of the arch of the aorta (Figure 5).

The mediastinoscope is then passed gently along the lateral border of the aorta into the node-containing fat pad, which is always present in the location. Ultimately, one encounters lymph nodes which, following suitable dissection, are biopsied (Figures 6 & 7).

One can extend the inspection down to the pericardium overlying the pulmonary artery and superior pulmonary vein. In this procedure, care is taken not to transgress the pleura unless a pleuroscopy is required, the tunnel being created between the pericardium and pleura.

This "extended mediastinoscopy" however can also include pleuroscopy as described by Deslauriers et al. To do this, a left bronchial blocker or double lumen tube is placed prior to the mediastinoscopy so that the left lung can be collapsed. At the time of extended mediastinoscopy, the pleura is identified and opened using blunt dissection and the mediastinoscope enters the left hemi-thorax. The combined use of the mediastinoscope and a thoracoscope will allow inspection of a large portion of the hemithorax.

Tips and Pitfalls

Before embarking on extended cervical mediastinoscopy, I recommend a trip to the autopsy room to practice the technique or, following standard cervical mediastinoscopy when a Chamberlain procedure is to be performed, utilizing this opportunity to gain experience with the technique after the Chamberlain procedure has been carried out and both incisions are opened. Bi-manual palpation through the Chamberlain opening and the cervical mediastinoscopy opening will allow one to create the appropriate window with the guidance available through the Chamberlain opening, thus allowing the procedure to be done almost under direct vision.

Results

Virtually all the extended cervical mediastinoscopies attempted are successfully completed and lymph nodes are obtained for pathologic examination. On occasion, the window and tunnel that are created digitally are not large enough to allow the mediastinoscope to proceed properly into the anterior mediastinum. When this occurs, this approach should be abandoned. In over 15 years of using this technique only one major complication has occurred--a small laceration of the base of the innominate artery due to the use of a sharp-tipped suction catheter inadvertently handed to the surgeon by mistake. This was repaired by sternotomy, and a left upper lobectomy was performed at the same time without incident. One other complication has been reported by Urschel--a transitory stroke, which may or may not be related to the "extended" portion of the mediastinoscopy since it has been reported after standard cervical mediastinoscopy.





© 2002 Cardiothoracic Surgery Network.