The patient is positioned in the supine decubitus under general anaesthesia and orotracheal intubation. Double-lumen intubation will be required if exploration of the pleural cavities is anticipated, by either mediastino-thoracoscopy or standard intercostal thoracoscopy. Hyperextension of the neck is achieved by a long cushion positioned under the patient’s shoulders. A round rubber cushion keeps the head in place and avoids displacement during the operation (Fig. 2.5). The operative field is prepared and draped as for median sternotomy, from under the mandible cranially to the xiphoid caudally and from nipple to nipple laterally. An extra drape is put over the sternum below the sternal notch to be easily removed if emergency sternotomy is required (Fig. 2.6). A peripheral vein in one arm or hand is cannulated for infusion of fluids and medication. An additional vein access in a foot is recommended for fast infusion of fluids and blood in case of copious bleeding from a mediastinal vessel (Fig. 2.7). Intraoperative monitoring includes EKG, blood pressure and right arm pulse (Fig. 2.8). The latter is useful to control excessive pressure exercised on the innominate artery during mediastinoscopy. The pulse wave will diminish or even disappear if the innominate artery is compressed against the anterior chest wall by the mediastinoscope. Compression can be easily relieved by repositioning the mediastinoscope. The surgeon stands or sits at the head of the patient, and the assistant and the scrub nurse either stand or sit on the right side. The television monitor for video-mediastinoscopy is positioned at the patient’s feet, slightly on the left.

A 5-cm collar incision is performed immediately cranial to the sternal notch. A low cervical incision gains a few centimetres and allows the mediastinoscope to be inserted more deeply into the mediastinum. The incision is carried out through the subcutaneous tissue and the platysma. Anterior jugular veins in the midline can be ligated if they interfere with the dissection. The pretracheal muscles are separated laterally with Farabeuf retractors. If the thyroid grand is found in the midline, it can be retracted cranially to expose the trachea. At this point, the anterior tracheal wall is identified. The pretracheal fascia is held with forceps and incised with scissors (Fig. 2.9). An index finger is inserted into the incision, anterior to the trachea, and the pretracheal fascia is torn as caudally as the finger allows (Fig. 2.10).

This initial palpation with the index finger should be able to identify the pulse of the innominate artery, anteriorly and on the right, as well as that of the aortic arch, in the midline and on the left. The finger separates the peritracheal fatty tissue from the anterior and lateral walls of the trachea; feels the consistency and adhesion of the surrounding tissues, tumours or lymph nodes; and creates a pretracheal space for the insertion of the mediastinoscope.

The mediastinoscope is inserted along the anterior wall of the trachea. When the neck is hyperextended, the mediastinoscope is inserted parallel to the trachea. In case of neck rigidity, the mandible interferes with the mediastinoscope, but it still can be inserted in a more perpendicular way to direct its tip to the target lesion (Fig. 2.11). In patients with laryngectomy and tracheostomy, the cervical incision is performed caudal to the tracheostomy, and the mediastinoscope is inserted as in a regular case (Fig. 2.12). From this point on, the exploration is performed much more comfortably if the surgeon sits on a chair at the patient’s head, and the height of the operating table is at a lower level than the surgeon’s shoulders to avoid any strain on the surgeon’s shoulders and elbows. The pulsation of the innominate artery and of the ascending aorta should be identified. The pretracheal fascia is then further dissected caudally with the dissection-coagulation-suction device till the carina and both main bronchi are clearly seen. In most cases, dissection can be followed along the whole length of both main bronchi. On the right, the azygos vein should be identified at the tracheobronchial angle. This is an important landmark, because, according to the lymph node map proposed by the International Association for the Study of Lung Cancer, nodes caudal to the lower rim of the azygos vein are now called, for taxonomical reasons and for prospective evaluation, hilar nodes although they are located in the mediastinum [55] (Fig. 2.13 and Table 2.1). The right pulmonary artery runs anterior to the subcarinal space and can be followed over the right main bronchus. The left pulmonary artery is identified over the left main bronchus, and nodes caudal to its upper rim are called hilar nodes [55]. The dissection already performed to identify these anatomical landmarks of the superior mediastinum allows the surgeon to assess the peritracheal tissues, to see the mediastinal lymph nodes, mediastinal tumours or any other lesions that are the target of the exploration.

With the mediastinoscope, the following mediastinal nodal stations can be reached: supraclavicular, right and left superior and inferior paratracheal, right and left hilar and subcarinal. Quite often, the para-oesophageal nodes can also be removed or biopsied (Fig. 2.13 and Table 2.1). However, the thoroughness of mediastinoscopy depends on its objective. For diagnostic purposes, biopsy of the abnormal lesions might be enough for pathological studies or culture. For nodal staging in cases of bronchogenic carcinoma with abnormal lymph nodes on CT or PET, biopsy of the abnormal contralateral nodes to prove N3 disease may be enough, unless special studies or protocols require a more thorough exploration. For abnormal ipsilateral nodes to the tumour, biopsy of the abnormal nodes to confirm N2 disease has to be complemented with the assessment of the contralateral nodes to confirm or rule out N3 disease; otherwise, it may pass unnoticed. The ESTS recommends to explore and to take biopsies of the right and left inferior paratracheal lymph nodes and of the subcarinal lymph nodes for a mediastinoscopy to be considered acceptable in standard clinical practice [30]. However, biopsies from these three nodal stations may be insufficient for patients in whom the mediastinum looks normal on CT and PET but require mediastinoscopy for other indications. For these patients, the revised ESTS guidelines recommend the use of the video-mediastinoscope and to perform lymphadenectomy instead of taking biopsies of a few nodes. The idea behind this recommendation is to identify nodal disease that may be missed if only a few nodes are biopsied or removed [56].

Biopsies of tumours or lymph nodes are taken with biopsy forceps. Tissues must be well dissected and identified before biopsies are taken. Mediastinal lymph nodes are black or dark blue, and veins may be mistaken for nodes. In case of doubt, it is advisable to puncture the structure to be biopsied with a needle attached to a glass tube connected to suction and see if blood comes out of it. If blood is seen in the tube, the needle is withdrawn, and the puncture site compressed with gauze for a few minutes. If there is no bleeding, then the biopsy can be taken safely. This manoeuvre is not so necessary if the video-mediastinoscope is used, because structures can be better recognised. During dissection with the dissection-suction-coagulation device, small lymph nodes or nodal fragments can be aspirated. If these samples are considered important for diagnosis, the aspirate can be filtered at the end of the operation, and the samples recovered for pathological study (Fig. 2.14). Quantification of nodal disease has prognostic implications [57]. To facilitate the counting of explored and involved lymph nodes, each removed node or all the fragments of a single node are kept in an individual container that is labelled with the name of the patient and the name or the number of the nodal station (Fig. 2.15).

All biopsy sites should be controlled for haemostasis before closing. The azygos vein, the superior vena cava, the small tributary veins to the superior vena cava, the pulmonary arteries and the bronchial arteries should be carefully checked. Gauze compression for a few minutes is usually enough to control small blood oozing from fatty tissue. To avoid tumour implantation in the cervical incision, the biopsy specimens and the gauzes used for haemostasis must be removed along the mediastinoscope to minimise contact with the incision (Fig. 2.16).

For closure, the pretracheal muscles are not sutured to the midline, and the incision is closed in two layers: platysma and subcutaneous tissue together with absorbable 2-0 sutures and the skin with intradermal absorbable 3-0 sutures.

Patients are usually awakened and extubated in the operating room and taken to the recovery room till they are fully awake. Oral intake can be restarted 6 h after the operation. If the hospital has an outpatient surgery programme, the patient can be sent home. Readmission rate ranges from 1 to 5 %, mainly because of supraventricular arrhythmias and pneumothorax [58–61]. Postoperative chest x-rays are not required unless the patient has respiratory symptoms, the mediastinal pleura was opened or bleeding occurred during the procedure.

From the cervical incision, the mediastinoscope can be slipped behind the sterno-clavicular insertions of the sternocleidomastoid muscle to reach the scalene fat pad [62]. This topic is covered in Chap.​ 1 of this book.