respectively [5]. A step forward was the insertion of a laryngoscope through the cervical incision performed to reach the scalene fad pad. This exploration was a limited unilateral mediastinoscopy and was published in 1954 by Harken et al. [6] One year later, Radner used an incision over the cervical midline to explore the paratracheal lymph nodes [7].

Mediastinoscopy was quickly spread in Europe as the books by Otto Jepsen [8] and by Tauno Palva [9] show. The main advantage of mediastinoscopy was that it allowed the diagnosis of intrathoracic diseases with no need to open the chest cavity. For lung cancer, diagnosis and staging were simultaneous in many cases. Tuberculosis, sarcoidosis, silicosis, vascular anomalies, mediastinal tumours and in ammation could also be diagnosed via this transcervical approach. Its systematic indication in the clinical staging before lung resection showed that those lung cancers with involved mediastinal lymph nodes identifed at mediastinoscopy had worse prognosis than those with nodal disease identifed at thoracotomy [10]. This gave a prognostic perspective to the procedure in addition to diagnosis and staging. With the introduction of computed tomography (CT) in clinical practice, the most common trend was to indicate mediastinoscopy when there were abnormal lymph nodes [11]. However, some authors favoured its systematic use, regardless of the size of the lymph nodes on CT, even for early stages [12].

The design of the video-mediastinoscope by Lerut in 1989 and of the two-bladed video-­ mediastinoscope by Linder and Dahan in 1992 increased the possibilities of the exploration for staging and therapeutic indications, leading to mediastinal lymphadenectomy and complex therapeutic procedures, such as closure of bronchopleural fstula and lobectomy through the transcervical approach [13–17].

Indications and Contraindications

For lung cancer staging, the guidelines of the American College of Chest Physicians (ACCP) revised in 2013 recommend invasive nodal staging in the following situations: (a) discrete medi-

astinal lymph node enlargement with or without positron emission tomography (PET) uptake in mediastinal lymph nodes; (b) PET activity in mediastinal lymph nodes and abnormal lymph nodes on CT; (c) high suspicion of N2 or N3 disease either by lymph node enlargement on CT or PET uptake and (d) intermediate suspicion of N2 or N3 disease by CT and PET, a central tumour or N1 disease. According to these guidelines, invasive mediastinal staging would not be indicated in patients with massive mediastinal infltration or in those with stage IA tumours without any mediastinal nodal abnormality on CT and PET [18].

In a similar way, the recommendations for invasive mediastinal staging of the revised European Society of Thoracic Surgeons (ESTS) guidelines are (a) positive mediastinal nodes on CT, PET or PET-CT; and (b) when there is no evidence of N2–N3, but there is suspicion of N1 disease, in central tumours larger than 3 cm and in adenocarcinomas with high PET uptake. Invasive staging could be spared in patients with no enlarged lymph nodes on CT or abnormal uptake on PET and tumours less than 3 cm in greatest dimension located peripherally in the outer one-third of the lung [19].

The ACCP and the ESTS favour the use of endoscopic procedures for initial invasive staging, such as transbronchial needle aspiration (TBNA), endobronchial ultrasound-guided fne-­ needle aspiration (EBUS-FNA) or oesophageal ultrasound-guided FNA (EUS-FNA). If these explorations are positive for cancer, the information may be adequate to start a multidisciplinary treatment protocol. However, if they are unavailable or negative, a surgical technique is recommended, instead, to confrm their negative results, because their negative predictive value is too low to make further therapeutic decisions [18, 19]. Regarding the indication of a surgical technique to confrm a negative result of an ultrasound-­ guided endoscopic needle aspiration or biopsy, the North American guidelines state that a surgical technique should be performed when there is high suspicion of nodal involvement [18]. On the other hand, the European guidelines recommend either EBUS-TBNA/EUS-FNA or video-assisted mediastinoscopy for tumours with an intermedi-

ate risk of nodal disease (central tumours, suspicion of N1 by CT and/or PET, tumours larger than 3 cm and adenocarcinomas with a high PET uptake) depending on the local expertise and adherence to the minimal requirements for staging [19]. The ambiguity of both guidelines regarding what has to be done after a negative endoscopy may be responsible for the fact that not all negative results of EBUS-TBNA/EUS-­ FNA are confrmed by a surgical technique. When the latter are performed, mediastinoscopy usually is the procedure of choice, but mediastinotomy or thoracoscopy could be performed if the target lesion is within the range of these explorations.

The ESTS guidelines also recommend to pathologically confrm tumour response after induction therapy. As at initial staging, this can be done by endoscopic techniques, but if their results are negative, then a surgical procedure is recommended. Over the years, remediastinoscopy has proved to be a safe and reliable restaging method [20–22]. It is important to confrm or rule out persistent nodal disease and tumour progression after induction therapy. Persistent nodal involvement and progressive disease are unfavourable prognostic factors and lung resection should be avoided because it does not add any survival beneft [20, 23, 24]. With the increased use of EBUS-TBNA and EUS-FNA for initial staging, the sequence ‘staging mediastinoscopy-­ restaging remediastinoscopy’ is not so common now. If nodal disease has been diagnosed at staging endoscopy, then the same endoscopy can be used for restaging. If this is negative, mediastinoscopy can be indicated to confrm the results. This restaging mediastinoscopy will not be a reoperation and will be performed without having to negotiate the adhesions caused by the initial exploration. Alternatively, thoracoscopy can be used for restaging after a staging mediastinoscopy with results similar to those of remediastinoscopy [25].

There are very few contraindications. Severe neck rigidity and large goitres are anatomic abnormalities that can prevent the correct insertion of the mediastinoscope, but they are extremely rare in lung cancer patients. Aortic aneurism is a contraindication, because the aortic

arch is compressed by the mediastinoscope when it is inserted in front of the trachea and may be injured. Abnormal coagulation tests are a relative contraindication. As in any other intervention, they should be corrected before the operation and the operation rescheduled when they are normalized. In the past, superior vena cava obstruction, a previous mediastinoscopy or a previous mediastinal operation by median sternotomy, tracheostomy or total laryngectomy were considered contraindications, but experience has proved that mediastinoscopy can be performed safely when other less invasive procedures have not established a diagnosis [26, 27].

Description of the Equipment

Needed

General

For the incision and initial dissection, the following instruments are needed: standard surgical knife, dissection forceps, Mayo and Metzenbaum scissors and a right-angle dissector. Silk 2-0 sutures may be necessary to ligate small anterior jugular veins. Absorbable 2-0 and 3-0 sutures are used to close the incision in two layers: platysma and subcutaneous tissue together and skin, respectively.

Speci c

There are two types of scopes: the conventional ones and the video-mediastinoscopes that, since the late 1980s, are progressively replacing the former. Mediastinoscopes are in the right-angle shape, with the vertical arm as handle and the horizontal arm, in the shape of a truncated cone, as the scope proper. The conventional mediastinoscopes are in a single piece and the video-­ mediastinoscopes are made either in a single piece or in two spreadable blades to widen the operative feld. Video-mediastinoscopes are connected to a camera and the exploration is seen on a television monitor. The equipment is completed with a light source and a recorder to register the operations.

The dissection-suction-coagulation device is fundamental to dissect and identify the lymph nodes from the peritracheal fatty tissue. Suction keeps the operative feld clean at all times and coagulation controls bleeding from small veins, lymph nodes or fatty tissue.

A glass tube connected to a needle on one end and to suction on the other is used for puncture test when the nature of the structure to be biopsied is not clear. This is more useful when the conventional mediastinoscope is used. Mediastinal structures are much better seen with the video-mediastinoscope and this makes the puncture test rarely necessary.

There are several types of biopsy forceps. Some are spherical and others, oval, and they come in different sizes.

There also are several types of graspers and ring forceps that allow the surgeon to hold the tis-

sue with one hand and dissect with the other, while the assistant holds the mediastinoscope in place.

Endoscopic clips should be available in case clipping of the bronchial arteries is necessary. The new energy devices for haemostasis and cutting may reduce the risk of bleeding and are easy to use especially with the two-bladed video-­ mediastinoscope that allows a larger operative feld for the insertion of these devices. They are especially valuable at the beginning of the learning curve to reduce the risk of bleeding and of injury of the left recurrent laryngeal nerve, because the heat does not spread to the tissues close to the blades of the device. These devices can safely coagulate vessels of up to 8 mm in diameter.

Figure 27.1 shows the basic instruments for mediastinoscopy; and Fig. 27.2, the general view of the operative feld. Figure 27.3 shows the use of an energy device in the subcarinal space.

Fig. 27.1  Basic instruments set: (a1) Biopsy forceps with oval jaws, size 8 mm × 16 mm. (a2) Biopsy forceps with spherical jaws, size 5 mm. (b) Dissection-suction-coagulation

cannula. (c) Glass tube connected to a needle for puncture test. (d) Linder-Dahan two-bladed spreadable video-medias- tinoscope. (e) Lerut video-mediastinoscope