ing of biopsies should start on the contralateral side to the tumour to rule out N3 disease. Macroscopically abnormal nodes should be sent for frozen section examination and, if nodal involvement is identifed, mediastinoscopy may be terminated unless the patient is in a protocol that requires more information on the extent of nodal disease. Then, the subcarinal and the ipsilateral paratracheal nodes are biopsied. If the nodes are not removed entirely, the initial biopsies of each lymph node are ideal to examine the involvement of the nodal capsule and the extranodal tumour invasion. Each complete node or all the biopsies from one node are kept in a container and properly labelled according to the present nodal nomenclature [1]. This makes the counting of the removed and involved nodes much easier and reliable (Fig. 27.6). Whenever possible, it is better to remove the entire nodes to avoid missing micrometastases and increase the sensitivity of the exploration. Mediastinal lymph nodes are embedded in the peritracheal fatty tissue. Exploration of this fatty tissue with the dissection-­ suction-­coagulation device allows the surgeon to identify them and free them from their surroundings. Sometimes, fragments of lymph nodes or whole small lymph nodes are suctioned during dissection. In this case, it is recommendable to flter the contents of the suction container to retrieve the suctioned lymph nodes or their fragments for pathological examination.

Mediastinoscopy allows the surgeon to reach the cervical nodes at the sternal notch, the supe-

rior and inferior paratracheal nodes on both sides, the subcarinal nodes and the right and left hilar nodes. However, the superior paratracheal nodes are hidden by the mediastinoscope when it is inserted and are not easy to identify. They are better explored and biopsied in the open fashion at the time of cervicotomy. The European Society of Thoracic Surgeons (ESTS) guidelines require biopsies from, at least, one right and one left inferior paratracheal nodes, and one subcarinal node for an acceptable mediastinoscopy in clinical practice. In addition, the superior paratracheal and hilar stations should be explored, if there is imaging suspicion of nodal involvement. For cancers of the left lung, exploration of the subaortic and para-aortic nodes is also required, either by left parasternal mediastinotomy, extended cervical mediastinoscopy or left thoracoscopy [19] (Fig. 27.7).

Control of Haemostasis and Closure

The use of the dissection-suction-coagulation cannula minimizes bleeding during dissection of peritracheal tissue. Mediastinal lymph nodes usually are dark blue or black because of their anthracotic content. The azygos vein or a partially visualized superior vena cava may resemble lymph nodes. In case of doubt, especially if the standard mediastinoscope is used, a puncture test should be performed. If blood is seen along the glass suction tube, the needle should be

Fig. 27.7  Endoscopic images of video-mediastinoscopy. (a) Proximal trachea. (b) Distal trachea, right and left main bronchi. (c) Right hilar lymph node. This lymph

node is located caudal to the inferior rim of the azygos vein (yellow arrows). (d) Hilar lymph node biopsy

removed and the bleeding site gently pressed with gauze for haemostasis. During this manoeuvre, care must be taken not to puncture through the trachea, because perforation of the endotracheal cuff is possible and already has been described [30]. All biopsy sites should be checked before closure. Coagulation of biopsied lymph nodes or peritracheal fatty tissue is enough to control bleeding. Control of bleeding from the bronchial arteries in the subcarinal space, especially those running in front of the left main bronchus, should be tried frst with gauze packing and coagulation. If bleeding persists, clipping or coagulation with energy devices of the bronchial artery may be necessary. The gauze used for packing must be removed through the mediastinoscope to minimize tumour seeding in the cervi-

cal incision. Tumour cell dissemination during mediastinoscopy is possible. Cytological analyses of mediastinal lavage uid have shown that tumour cells can be identifed before and after taking biopsies, although long follow-up periods are needed to understand their prognostic value [31]. Major bleeding is an uncommon complication that may occur in 0.4% of procedures and may come from the azygos vein, the pulmonary arteries, the innominate artery - the most common sites of serious bleeding -, the superior vena cava and the aorta. Packing and median sternotomy or thoracotomy, depending on the location of bleeding, is the usual procedure of haemorrhage control [32]. The choice of access to the chest is important because each provides a different exposure to the intrathoracic vessels. The