Procedure

Videomediastinoscopy

University Hospitals Leuven, Department of Thoracic Surgery, Herestraat 49, B-3000 Leuven, Belgium

^* Corresponding author: ^* Tel.: +32 16 346822, fax: +32 16 346821, Email: paul.deleyn{at}uz.kuleuven.ac.be

	Summary

Top Summary Introduction Advantages Types of videomediastinoscopes Technique-cervical... Technique-repeat... References

 
The use of videotechniques in mediastinoscopy has increased the quality of mediastinal lymph node staging due to improved visualisation and magnification on the screen. The anatomical landmarks are much more easily identified. Teaching with standard mediastinoscopy is difficult as the working channel is small. Videomediastinoscopy has made teaching much easier. It is hoped that videotaping accompanying this article may contribute to standardisation and refinement of this very important and frequently performed procedure. Indications, technique, results and complications are discussed in more detail in the procedure on conventional mediastinoscopy.

Key Words: Non-small cell lung cancer • nodal staging • video-assisted

	Introduction

Top Summary Introduction Advantages Types of videomediastinoscopes Technique-cervical... Technique-repeat... References

 
Conventional equipment for cervical mediastinoscopy obliges surgeons to work in an uncomfortable position. Only he or she has a view through the instrument. Teaching is extremely difficult because of the danger of damaging vital organs. The development of videoscopic and video-assisted technology during recent years has opened up new perspectives in surgical practice.

The credit for bringing videomediastinoscopy to the international thoracic surgery community attention goes to T. Lerut who presented the concept, developed in 1989 at the First International Symposium on Thoracoscopic Surgery in San Antonio in January 1993 [1]. We further described the technique and its indications [Ref. [2], and Footnote ¹]. Subsequently, the instrumentation of the videomediastinoscope was further developed and refined by different authors and companies. Several authors have reported their experiences with the use of videomediastinoscopy [3, 4].

	Advantages

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Better imaging
The magnified image on the screen offers a much more detailed image (Photo 1).

View larger version (74K): [in this window] [in a new window]   Photo 1 Improved visualisation by the use of the videomediastinoscopy. A: even the small vasculare of the trachea is clearly visible at this level of magnification. B: view of right pulmonary artery and right main bronchus. C: the left recurrent nerve.

Bimanual preparation (Photo 2)
Hurtgen et al. [5] have shown that using bimanual dissection complete lymph node dissection is feasible through the videomediastinoscopy, the so-called video-assisted mediastinal lymph node dissection (VAMLA [5]). Sensitivity and negative predictive value is increased by performing videomediastinoscopy [6].

View larger version (86K): [in this window] [in a new window]   Photo 2 (A and B) Since the working channel is somewhat broader and as the instruments do not obscure the view, bimanual preparation is feasible. The scope can be held by an assistant who can also follow the intervention.

View larger version (99K): [in this window] [in a new window]   Photo 3 Classic mediastinoscopy is a difficult procedure to teach as the working channel is narrow. With direct imaging on a TV monitor and simultaneous video recording several people can follow the operation; this offers greater teaching capabilities.

	Types of videomediastinoscopes

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At the moment, two types of videomediastinoscopes are available (Photos 4 and 5).

View larger version (134K): [in this window] [in a new window]   Photo 4 The Lerut scope (K. Storz, Tuttlingen, Germany) resembles the normal mediastinoscope with light optics built into the framework of the scope.

View larger version (70K): [in this window] [in a new window]   Photo 5 The scope from Wolf (Richard Wolf, Knittlingen, Germany) may be considered as a two-bladed speculum. The inferior valve may be opened widely, allowing exposure of mediastinal structures and creation of an operative field for bimanual surgery.

	Technique-cervical videomediastinoscopy

Top Summary Introduction Advantages Types of videomediastinoscopes Technique-cervical... Technique-repeat... References

View larger version (91K): [in this window] [in a new window]   Photo 6 (A and B) Operation room set-up for videomediastinoscopy.

Click on image to view video Video 1 Introduction of the scope. The isthmus of the thyroid is retracted superiorly. The scope is introduced in front of the trachea under the pretracheal fascia. One has to be careful not to avulse the inferior thyroid veins. After some more dissection, the arterial vessels (the innominate artery and left common carotid artery) are easily identified. The scope is advanced under these vessels.

Click on image to view video Video 2 The plane in front of the videomediastinoscope is developed with blunt dissection, using the metal suction device. The scope is advanced underneath the pretracheal fascia.

Click on image to view video Video 3 The dissection starts with visualisation of the anatomical landmarks such as the carina, on the right side the azygos vein, the first branch of the right pulmonary artery. On the left side, the left main bronchus and the left pulmonary artery are visualised before any biopsies are taken. In this patient, a massively involved subcarinal node was found.

Click on image to view video Video 4 The left recurrent nerve lies approximately 1 cm lateral to the trachea and can usually be easily visualised in the mid tracheal plane. From there it can be followed more distally. One should not use monopolar coagulation in this region to avoid thermal damage of the left recurrent nerve.

Click on image to view video Video 5 Small bleeding sites can be coagulated.

Click on image to view video Video 6 Bronchial arteries are easily identified and if necessary they can be clipped.

Click on image to view video Video 7 The lymph nodes lie outside of the fascial envelope and the pretrachial fascia has to be broken before a biopsy can be taken. Prior to biopsying the lymph node, the node should be mobilised as much as possible to ensure that it is a lymph node and not a vessel. This mobilisation is performed by the use of the metal suction device. For the upper paratracheal lymph nodes this can be safely performed with the finger.

Click on image to view video Video 8 On the right side, one has to be careful when a biopsy is taken from a lymph node fixed to the first branch of the right pulmonary artery.

Click on image to view video Video 9 In the subcarinal area, bleeding will immediately occur at the biopsy sites. This bleeding is usually not severe but obscures dissection and sampling. By pushing the scope deeper in the subcarinal space the bleeding will stop and this allows to take more representative biopsies before the bleeding sites are electrocoagulated. At the end of the procedure, a resorbable hemostatic gauze is placed in the subcarinal biopsy area.

Click on image to view video Video 10 In case of doubt, a long aspiration needle can be placed in the lymph node and suction is applied to the attached syringe, to confirm that the structure to be biopsied is not a vessel. The case demonstrated on the video is a repeat mediastinoscopy. After puncture of what appeared to be a lymph node (station 7), a safe biopsy was taken.

Click on image to view video Video 11 The left recurrent nerve is easily identified in the left paratracheal plane. Usually at its medial side a lymph node is located at the tracheobronchial angle (station 4L). Biopsy of this lymph node should be done with caution and is best performed from the medial site of this node in order to avoid injury to the recurrent laryngeal nerve.

Click on image to view video Video 12 In case of involvement of the subcarinal lymph nodes, the right pulmonary artery needs to be dissected off from the involved nodes in order to safely take the biopsies. In this case, the subcarinal nodes were macroscopically massively positive.

Click on image to view video Video 13 On the left paratracheal side, the esophagus may be identified. Care is taken not to damage the esophagus when taking biopsies of left paratracheal lymph nodes.

Click on image to view video Video 14 After removal of the subcarinal nodes, the esophagus is visualised. Again one has to be careful not to injure the esophagus when taking biopsies.

Click on image to view video Video 15 In left upper lobe tumors, when there is clinical suspicion of involved nodes subaortic or in the aortopulmonary window, an extended mediastinoscopy is an alternative to left anterior mediastinotomy or VATS. After a negative cervical videomediastinoscopy, blunt dissection is performed with the finger anterior to the innominate artery, in between the innominate artery and the innominate vein. The videomediastinoscope is introduced in this plane above the aortic arch. The scope is advanced over the top of the aortic arch down to the aortopulmonary window. Biopsies of nodes in the aortopulmonary window are taken.

	Technique-repeat videomediastinoscopy (Videos 16 and 17)

Top Summary Introduction Advantages Types of videomediastinoscopes Technique-cervical... Technique-repeat... References

Click on image to view video Video 16 The brachiocephalic trunk is adherent to the anterior surface of the trachea due to fibrosis. Blunt dissection is performed on the left side of the trachea which has not been extensively dissected during previous mediastinoscopy. A left paratracheal tunnel is created (medial border is trachea, the inferior surface is part of the esophagus). Dissection is continued on the left side until the left tracheobronchial angle is visualised. Starting from this tunnel, blunt dissection is now commenced from below in a retrograde fashion. The anterior surface of the trachea is freed from the major vascular structures. Strong adhesions can be divided with the endoscopic scissors.

Click on image to view video Video 17 Blunt dissection can be performed with the suction device. A good and safe alternative is using a dissection pledget. Once more space is gained; this dissection can be carried on by finger dissection. One has to do this carefully in order not to enter the brachiocephalic artery.

	Footnotes

	References

Top Summary Introduction Advantages Types of videomediastinoscopes Technique-cervical... Technique-repeat... References

 

1. Coosemans W, Lerut T, Van Raemdonck D. Thoracoscopic surgery: the Belgian experience. Ann Thorac Surg 1993;56:721–30[Abstract]
2. De Leyn P, Lerut T. Videomediastinoscopy. Minimal access in cardiothoracic surgery. W.B. Saunders Company 2000. Chapter 22:169–74.
3. Venissac N, Alifano M, Mouroux J. Video-assisted mediastinoscopy: experience from 240 consecutive cases. Ann Thorac Surg 2003;76:208–12[Abstract/Free Full Text]
4. Lardinois D, Schallberger A, Betticher D, Ris HB. Postinduction videomediastinoscopy is as accurate and safe as videomediastinoscopy in patients without pretreatment for potentially operable non-small cell lung cancer. Ann Thorac Surg 2003;75:1102–6[Abstract/Free Full Text]
5. Hurtgen M, Friedel G, Toomes H, Fritz P. Radical video-assisted mediastinoscopic lymphadenectomy (VAMLA): technique and first results. Eur J Cardiothorac Surg 2002;21:348–51[Abstract/Free Full Text]
6. Leschber G, Holinka G, Linder A. Video-assisted mediastinoscopic lymphadenectomy (VAMLA) – a method for systematic mediastinal lymph node dissection. Eur J Cardiothorac Surg 2003;24:192–5[Abstract/Free Full Text]
7. Martin-Ucar AE, Chetty GK, Vaughan R, Waller DA. A prospective audit evaluating the role of video-assisted cervical mediastinoscopy as a training tool. Eur J Cardiothorac Surg 2004;26:393–5[Abstract/Free Full Text]