Application of the Technique

The surgical technique is essentially the same Carlens described in 1959, [3] but several variants have been developed to widen the range of the exploration and to increase its sensitivity.

Patients planned to undergo mediastinoscopy should have a complete history and physical examination. It is important to know if the patient had previous interventions in the neck

and in the mediastinum, i.e. cervicotomy for goitre or neck tumours, tracheostomy, laryngectomy or median sternotomy for mediastinal or heart diseases. These rarely contraindicate mediastinoscopy, but the surgeon should be aware of them. Neck exibility should be checked, too, because it is important to properly insert the mediastinoscope. Complete blood count and biochemistry, as well as coagulation tests, should be available before the operation. For those patients with high or moderate risk for thromboembolism (patients with a mechanical heart valve, atrial fbrillation or venous thrombosis) bridging anticoagulation is recommended with therapeutic doses of subcutaneous low- molecular-weight heparin fve days before the operation. Regarding the perioperative antiplatelet therapy, it is recommended to stop aspirin and clopidogrel 5–7 days prior to surgery and restart within 24 h after surgery, except for doses of 100 mg of aspirin, that do not need to be stopped [28]. In any case, the discontinuation of anticoagulation and antiplatelet therapy should be assessed individually depending on the indication of the drugs and the risk of bleeding associated with the procedures [29].

Chest x-rays, CT of the chest and PET are necessary to identify the target areas in the mediastinum and should be available at the time of the operation. Although mediastinoscopy should be as complete as possible in all cases, if the surgeon knows the location of the abnormal lymph nodes or the site where the tumour contacts the mediastinum, these areas are not likely to be missed. The patient should be seen by an anaesthesiologist to assess the risk associated with general anaesthesia, and should be informed of the most frequent complications (left recurrent laryngeal nerve palsy, pneumothorax) and of the rare but potentially fatal ones (bleeding, tracheo-bronchial and oesophageal perforation), as well as of the potential need for blood transfusion. The patient is required to sign an informed consent form.

Patient’s Position and Operative Field

Under general anaesthesia and oro-tracheal intubation, the patient is positioned in the supine decubitus. A double-lumen oro-tracheo-­bronchial tube may be necessary if additional procedures are planned. For standard intercostal thoracoscopy or for mediastino-thoracoscopy, for which opening of the mediastinal pleura to reach the pleural space is required during mediastinoscopy, selective single-lung ventilation is needed to inspect the pleural space properly. The patient’s shoulders are raised with a long sand cushion. This allows some hyperextension of the neck and exposure of a long segment of the intrathoracic trachea, especially in young patients. The patient’s head is allowed to rest on a circular rubber pillow to prevent displacement during the operation. In addition to the EKG leads and the blood pressure cuff, a pulse metre is fxed in one right-hand fnger to control the occlusion of the innominate artery that may occur during mediastinoscopy, when excessive pressure is exercised on the artery with the mediastinoscope against the anterior chest wall. Repositioning the mediastinoscope will easily relieve this pressure (Fig. 27.4).

An operative feld is prepared and draped from the mandible, cranially, to the xiphoid, caudally, and from nipple to nipple, laterally. An extra drape is positioned caudal to the sternal notch to cover the sternum. In case median sternotomy is needed during mediastinoscopy, this drape can be quickly removed.

The surgeon either stands or sits at the head of the patient, depending on the moment of the operation. The assistant is besides the surgeon, on the right or on the left, and the scrub nurse stands on the right. The television monitors, if the procedure is performed with a video-­ mediastinoscope, are positioned at the patient’s feet and in front of the scrub nurse (Fig. 27.2).

Fig. 27.4  Patient with tracheostomy, a classic contraindication of mediastinoscopy. The patient had a centrally located tumour and mediastinoscopy was indicated to rule out mediastinal nodal disease. (a) Position of the patient for videomediastinoscopy. The neck is hyperextended and

the head rests on a circular pillow. (b) A double-lumen oro-tracheo-bronchial tube (black arrows) is inserted because a pleural inspection was planned. (c) Insertion of the videomediastinoscope. (d) View of the wound after closing the incision with absorbable intradermal suture

Incision and Initial Dissection

A 5-cm collar incision is performed as close to the sternal notch as possible. After incising the skin, subcutaneous tissue and platysma, the avascular midline is incised and the paratracheal muscles are dissected and separated laterally. Although this is a low-neck incision, sometimes the thyroid gland can be found covering the trachea. By blunt dissection and fnger retraction, the thyroid gland can be pulled cranially to allow the insertion of the mediastinoscope. The pretracheal fascia is intimately attached to the trachea. It is hold with dissection forceps and incised with scissors. The fascia is further separated from the trachea by fnger dissection: the index fnger is

inserted into the fascial opening and the fnger is carried caudally tearing most of the length of the pretracheal fascia.

Palpation

Contrary to other endoscopies performed in virtual cavities, i.e. the pleural cavity (pleuroscopy), the peritoneum (laparoscopy) or a joint (arthroscopy), there is no mediastinal space as such. A space must be created in the upper mediastinum by fnger dissection. In addition to creating an adequate mediastinal space, palpation allows the surgeon to feel the size, consistency and degree of attachment of mediastinal lymph nodes, medi-

Fig. 27.5  Endoscopic view of left paratracheal space. Black arrows show left recurrent laryngeal nerve. LMB left main bronchus; T trachea

astinal tumours or bronchogenic carcinomas with direct mediastinal contact or invasion.

Palpation must be systematic and the anatomical landmarks must be recognized. In the typical case, after inserting the distal phalange of the index fnger, the pulsation of the innominate artery can be felt. In young patients, when the neck is hyperextended, the innominate artery may become cervical and may be seen after completing the cervical incision. In older patients, the innominate artery may be located more caudally, if the neck cannot be hyperextended, or more cranial if the aortic arch is elongated. In all these circumstances, care must be taken not to injure it in these initial manoeuvres. Following the course of the innominate artery on the left, the aortic arch can be felt. Then, the fnger is passed more distally behind the aortic arch. By palpation, the tracheal cartilages can be felt. Close to the carina, they are disrupted, as the trachea separates into the two main bronchi.

Insertion of the Mediastinoscope

and Mediastinal Inspection

is performed more comfortably if the surgeon sits on a chair. The heights of the operating table and of the chair have to be regulated to relieve tension at the surgeon’s shoulders and elbows (Fig. 27.2).

From top to bottom, the pulsation of the innominate artery is seen frst. The pulsation of the ascending aorta is seen on the left. More caudally, at the level of the right tracheo-bronchial angle, the azygos vein can be identifed. The fatty tissue of the right paratracheal space has to be dissected to fnd the azygos vein. This landmark is important because, according to the new regional lymph node map, nodes caudal to the inferior rim of the azygos vein are coded as right hilar nodes, or 10R, although they are anatomically located in the mediastinum [1]. If the dissection is carried out more distally on the right, the whole length of the right main bronchus can be seen and, in some patients, even the origin of the right upper lobe bronchus. Over the right main bronchus the right pulmonary artery is found, usually the distal end of the exploration on the right. Over the subcarinal space, the prolongation of the pretracheal fascia has to be torn to reach the subcarinal nodes. The right pulmonary artery crosses in front of them and the oesophagus is behind. Care must be taken not to injure these structures. If the integrity of the oesophagus is questionable, a naso-oesophageal tube can be inserted and air injected into it. With the subcarinal space ooded with saline, an air leak will be evident if there is an oesophageal perforation. In more than three thousand mediastinoscopies, we have inserted a naso-oesophageal tube once, only, to rule out oesophageal perforation. On the left, it is important not to injure the recurrent laryngeal nerve that runs along the left paratracheal margin (Fig. 27.5). The left tracheo-­ bronchial angle can be identifed and, distal to it, the left pulmonary artery, marking the end of the exploration on the left. Nodes caudal to its upper rim are now coded as left hilar nodes, or 10 L [1].

Biopsy

After creating a peritracheal space by fnger palpation, the mediastinoscope is inserted into the upper mediastinum. At this point, the exploration

Lymph node biopsies for lung cancer staging must be systematically taken to obtain the maximal beneft from the exploration. Ideally, the tak-