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Mediastinoscopy & mediastinotomy indications & techniques

  1. MEDIASTINOSCOPY AND MEDIASTINOTOMY Professor Abdulsalam Y Taha School of Medicine Faculty of Medical Sciences University of Sulaimaniyah Sulaimaniyah Region of Kurdistan/ Iraq 1 https://sulaimaniu.academia.edu/AbdulsalamTah a
  2. Introduction  The mediastinum is the central compartment of the chest. Its boundaries and compartments are well known.  Although, it contains the most vital organs of the body; it is often a forgotten compartment. 2
  3. Introduction:  Involvement of mediastinal nodes has a dramatic prognostic and therapeutic impact in patients with non-small cell lung cancer.  Cervical mediastinoscopy remains the most important technique for staging of the mediastinum.  The technique of extended mediastinoscopy and redo mediastinoscopy are described as well. Indications, technique and complications are discussed. 3
  4. Introduction 4 * Lymph node sampling is an important intervention for the diagnosis and management of the mediastinal nodal disease, including benign and malignant etiologies. * The cervical mediastinoscopy is the ( gold standard) for the assessment of mediastinal lymph nodes and it remains the clinical method with the highest sensitivity and specificity for exclusion of mediastinal lymph node involvement.
  5. History 5
  6. Anatomy 6
  7. Nodal zones  Peripheral 12-14  Hilar 10 & 11  Upper 1-4  Aorto-pulmonary window 5 & 6  Subcarinal 7  Lower 8 & 9
  8. 8 Although cervical mediastinoscopy is used in the diagnosis of lymphoma, sarcoidosis and mediastinal tumors, it is mainly used as an invasive staging method in patients with non-small cell lung cancer (NSCLC). Surgical exploration of the mediastinum was first developed by Harken et al. Through a supraclavicular incision, a Jackson laryngoscope was inserted into the mediastinum and lymph node biopsies were taken. They reasoned that the presence of involved mediastinal lymph nodes in patients with lung cancer would preclude successfull resection of the cancer. More than fifty years later, their reasoning still proves to be very valid. Cervical mediastinoscopy through a pretracheal suprasternal incision was developed by Carlens in Sweden and subsequently popularized by Pearson in North-America. The prognostic importance of the level and extent of nodal involvement has led to the development of an internationally used lymph node map
  9. Indications  Lymph nodes or masses in the middle mediastinum of unknown origin (sarcoidosis, lymphoma, …).  Mediastinal staging in patients with NSCLC. 9
  10. There remains controversy regarding the selected use of mediastinoscopy in patients with NSCLC. Before PET scan became available, many centers used to perform cervical mediastinoscopy in every patient since it has been proved that small nodes on CT scan can harbor metastatic disease of clinical importance . There is consensus that the positive predictive value of both CT as well as PET scan is low and that positive mediastinal findings on CT or PET scan need to be proven histologically. Other less invasive techniques such as transbronchial fine needle aspiration and esophageal and tracheal endoscopic ultrasound needle aspiration have become available in specialized centers with high sensitivity in clinically obviously involved mediastinal nodes. The sensitivity and negative predictive value (NPV) of these techniques are, however, significantly lower when compared to mediastinoscopy and mediastinoscopy remains the gold standard. 10
  11. 11 * Cervical mediastinoscopy has a high accuracy. Its specificity is 100%, the sensitivity is dependent upon the surgeons experience but sensitivity rates of 90% are usually reported. Therefore, cervical mediastinoscopy remains the gold standard to which all other techniques are to be compared. * However, because PET scan has a high NPV up to 93% in primary mediastinal staging in patients with NSCLC [3] cervical mediastinoscopy can nowadays be omitted in some circumstances (peripheral tumor, N0 on PET and CT scan).
  12. 12 Contraindications: Absolute contraindications for cervical mediastinoscopy are very rare. 1. Contraindication for general anesthesia 2. Extreme kyphosis 3. Cutaneous tracheostomy (after laryngectomy) 4. Superior vena cava syndrome, previous sternotomy and enlarged goiter do not preclude mediastinoscopy as well as previous radiotherapy and mediastinoscopy. Due to fibrosis and adhesions the intervention can be much more challenging and is more time consuming.
  13. 13 Accessible lymph node stations by cervical mediastinoscopy By cervical mediastinoscopy the following nodal stations (according to the Mountain– Dresler modification (1997) from Naruke/ATS-LCSG Map) can be searched for and biopsied: the left and right upper paratracheal nodes (station 2L and 2R), left and right lower paratracheal nodes (station 4L and 4R) and the subcarinal nodes (station 7).
  14. The endotracheal tube is positioned at the left corner of the mouth, with the anesthesia equipment at the patients left side. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  15. Station 1 nodes are not routinely accessed by cervical mediastinoscopy. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  16. A horizontal line drawn tangential at the upper margin of the aortic arch delineates the lower border of station 2 nodes. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  17. Station 3 nodes are also not accessible by conventional cervical mediastinoscopy. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  18. The posterior subcarinal nodes (station 7p), the para-esophageal nodes (station 8), the inferior pulmonary ligament nodes (station 9) are not accessible by conventional media-stinoscopy. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  19. The subaortic nodes (station 5) and para-aortic nodes (station 6) cannot be biopsied through a standard cervical mediastinoscopy. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  20. A bolster is placed under the patients shoulders and the neck is extended. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  21. Operation room setup for conventional mediastinoscopy. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  22. 22
  23. For mediastinoscopy, only few instruments are needed. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  24. Conventional mediastinoscope. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  25. A 3 cm transverse cervical incision is made one-finger breadth above the suprasternal notch. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  26. Illustration of the anatomy of this region. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  27. Sharp dissection exposes the pretracheal muscles which are separated vertically in the midline to expose the anterior surface of the trachea. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  28. Incision of the pretracheal fascia. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  29. The surgeon's middle finger is advanced along the pretracheal plane and blunt dissection is carried out along the anterior surface of the trachea down to the carina. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  30. The mediastinum is carefully palpated for the presence of nodal disease. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  31. The finger is withdrawn and the mediastinoscope is advanced. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  32. The plane in front of the mediastinoscope is developed with the use of blunt dissection, using a metal sucker through the channel of the mediastinoscope. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  33. 33 • Prior to biopsying the lymph node, the node should be mobilized as much as possible to ensure that it is a lymph node and not a vessel. This mobilization is performed by the use of the suction device. • For the upper paratracheal lymph nodes this can be safely performed with the finger. • In case of doubt, a long aspiration needle can be placed in the lymph node and suction is applied to the attached syringe, to ensure that the structure to be biopsied is not a vessel. An experienced surgeon will find this seldom necessary when the nodes were adequately mobilized and the anatomical structures are clearly identified. • The lymph node is grasped with a biopsy forceps. In case of resistance, one should be cautious not to pull too strongly because the diseased lymph node may be attached to an adjacent vascular structure such as the azygos vein, the first branch of the right PA or the innominate artery. This may lead to a vascular tear with major bleeding
  34. To avoid and to handle major complications, it is important to visualize the anatomical landmarks such as the azygos vein, the right and left main bronchus and the first branch of the right pulmonary artery before biopsies are taken. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  35. The left recurrent nerve lies approximately 1 cm lateral to the trachea and can usually be visualized in the mid tracheal plane. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  36. Sequentially, the paratracheal tissues are entered to expose the lymph nodes at the various stations. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  37. 37 • One starts to biopsy the obvious enlarged nodes and those nodes that felt firm by palpation. • However, small lymph nodes may also contain metastatic deposits. • Routine sampling of all accessible mediastinal nodal stations is advised. • The standard is that biopsies of the subcarinal nodal station, two ipsilateral nodal stations and one contralateral nodal station are biopsied or removed. • The author uses adhesive labels on which the stations according to the Mountain– Dressler map are printed. This increases the accuracy in labelling
  38. The biopsies are stored in separate vials, labelled with these adhesive labels and sent for pathology. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  39. When biopsies are taken from the different nodal stations the biopsy forceps is cleaned each time to prevent contamination and false positive results. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  40. Mediastinoscopy. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  41. 41 • In the subcarinal area, bronchial arteries are frequently encountered and bleeding frequently occurs from the subcarinal lymph node biopsy sites. • This bleeding, although usually modest, obscures clear vision and further dissection and sampling. • In case a bronchial artery is visualized, a vascular clip can be placed. • Pushing the scope deeper into the subcarinal space the bleeding will stop which allows to take more representative biopsies before the bleeding sites are electrocoagulated. • Sufficient tissue has to be removed. In case of doubt, frozen section can be performed to confirm that sufficient tissue will be available. • When there is no histological diagnosis part of the lymph node is sent for culture.
  42. 42 Small bleedings from biopsy sites can be electrocoagulated. Bleeding is best handled with resorbable hemostatic resorbable gauze placed through the mediastinoscope. When a major bleeding occurs, packing is the first thing to do. By packing for at least 10 minutes, most of the even dramatic bleedings will stop. A long strip of wide gauze packing should always be available in the operating room for such instances. In case of uncontrollable hemorrhage (for instance injury of aorta or innominate artery), the mediastinum is packed or the bleeding site is compressed with the surgeon's finger, or the mediastinoscope, and the decision is made whether thoracotomy or sternotomy will be performed. Decision is based on the location of the bleeding and the location of the tumor if resection is indicated. Right thoracotomy might be indicated when the bleeding is from the first branch of the right pulmonary artery or from the azygos vein. In all other cases sternotomy offers the best chances to control the bleeding.
  43. 43 Closure • The strap muscles are approximated with one suture. • Drainage of the mediastinal bed is usually not required. • A subcutaneous interrupted suture will obliterate the dead space. • The skin is closed according to the surgeon,s preferences.
  44. 44 Morbidity & Mortality • Cervical mediastinoscopy is a low-risk procedure but the potential for catastrophic complications is apparent. • Unless additional or more extensive procedures are done under the same general anesthesia, and the patient's condition permits, the procedure can be performed on an outpatient basis. • In experienced hands, cervical mediastinoscopy has no mortality and minimal morbidity.
  45. • In a recent review of over 20000 cases complications did not surpass 2.5% and mortality was under 0.5%. • Only 0.1 to 0.5% of complications are considered major. •The most important major complication is a.severe hemorrhage. On the right side, the azygos vein and the anterior branch of the right pulmonary artery are at risk of injury. The azygos vein can be mistaken for an anthracotic lymph node. b.Other major complications are injury of the esophagus, c.damage to the recurrent laryngeal nerve (usually the left) and d.tracheobronchial tree injuries. 45 Morbidity & Mortality…
  46. 46 • In a twenty-year period, we performed well over 4000 cervical mediastinoscopies. • There was no hospital mortality. • Major bleeding requiring immediate intervention occurred in four patients, • injury to the esophagus was seen in one patient in whom the mediastinum was drained through the mediastinoscopy incision and this fistula dried up after a few days of conservative treatment. •In one case a tear of the left main bronchus was made by the biopsy forceps. This was sutured by the endoscopic suturing technique using the videomediastinoscope and healed without any problems.
  47. Left upper lobe tumors may metastasize to the subaortic lymph nodes (station 5) and paraaortic nodes (station 6). These nodes cannot be biopsied through routine cervical mediastinoscopy. Ginsberg and associates described a technique to explore these stations through the cervical incision. This technique is an alternative for the anterior-second interspace mediastinotomy which is more commonly used for exploration of these nodal stations. The advantage of the extended mediastinoscopy is the saving of an additional incision. 47 Extended Cervical Mediastinoscopy
  48. *If the standard cervical mediastinoscopy is negative, a plane is developed anterior to the aortic arch, down to the subaortic space. • To do so, blunt dissection is performed with the finger anterior to the innominate artery, between the innominate artery and the innominate vein. • The mediastinoscope is introduced through the cervical incision above the aortic arch. • The scope is advanced over the top of the aortic arch down to the aorto-pulmonary window. 48 Extended Cervical Mediastinoscopy; Technique
  49. If the standard cervical mediastinoscopy is negative, a plane is developed anterior to the aortic arch, down to the subaortic space. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  50. Biopsies of lymph nodes in the aortopulmonary window are taken. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery In experienced hands the procedure has a high accuracy and minimal morbidity. It is important to state that this procedure is far less easy and therefore is less routinely performed compared with the conventional mediastinoscopy.
  51. Repeat Mediastinoscopy  It is done for restaging of the mediastinal LNs after induction chemotherapy.  Induction chemotherapy is given to patients with N2 disease in order to achieve down staging of the tumour.  Precise restaging of the mediastinum after induction therapy for patients with involved mediastinal nodes (N2 or N3) disease is of utmost importance since confirmation of downstaging of mediastinal nodes is a very important prognostic factor in these patients.  Although PET scan has a high accuracy in primary staging of the mediastinum, its accuracy is much less in restaging of the mediastinum after induction therapy.  So, thoracic surgeons will be faced more and more frequently with the need to repeat the mediastinoscopy.  Several authors have shown that repeat mediastinoscopy is feasible with an accuracy of 85% and a sensitivity of 73%. 51
  52. Technique of repeat mediastinoscopy 52 *Positioning of the patient is not different from mediastinoscopy but the whole sternum is disinfected in case a sternotomy or hemiclamshell would be necessary. * The primary incision is reopened. Usually the isthmus or even the thyroid may be adherent to the trachea. Sharp dissection is performed to find the anterior surface of the trachea. The brachiocephalic trunk is adherent to the anterior surface of the trachea due to fibrosis.
  53. Repeat Mediastinoscopy. Blunt dissection is started on the left side of the trachea. This region was usually not extensively dissected at the previous mediastinoscop y and thus contains less fibrosis. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  54. A left paratracheal tunnel is created (medial border is trachea, the surface is part of the esophagus) and the scope is inserted. Leyn P D , Lerut T MMCTS 2005;2005:mmcts.2004.000158 © 2005 European Association for Cardio-thoracic Surgery
  55. 55 Repeat Mediastinoscopy: Technique….. * Dissection is continued on the left side until the left tracheo-bronchial angle is visualized. • From this tunnel, blunt dissection to the right side is performed from below in a retrograde fashion. • The anterior surface of the trachea is freed from the adherent major vascular structures. Initially this is perfomed with a dissection pledget. Once additional space is gained this can be continued by finger dissection. One has to do this carefully to avoid injury to the brachiocephalic artery. • The pretracheal space now being liberated, the scope can be changed in its normal position. Dense fibrosis and adhesions render the thorough exploration of all nodal stations very difficult or even impossible. • To reach the subcarinal region, the pulmonary artery has to be pushed away. Adhesions can be divided with the endoscopic shears. When there is a lot of precarinal fibrosis, we advise to dissect as far as possible on the left main bronchus. From there the sub-carinal space can be dissected and biopsied.
  56. Staging Lung Cancer - Mediastinoscopy
  57. Rigid video-mediastinoscopy 65 Case History: * An elderly man with enlarged paratracheal, subcarinal and aorto-pulmonary LNs. * Rigid video-mediastinoscopy was done under GA. * Needle aspiration of right paratracheal LN revealed a caseous material consistent with TB. * Multiple biopsies were taken.
  58. 66 Enlarged AP window Lymph nodes Enlarged para-tracheal Lymph nodes.
  59. 67 Enlarged sub-carinal Lymph nodes.
  60. 68
  61. 69
  62. Video assisted mediastinoscopy
  63. Anterior Mediastinotomy Indications & Technique 71
  64. Staging Lung Cancer - Mediastinotomy
  65. Staging Lung Cancer - Mediastinotomy
  66. Case A man of 30 presented with shortness of breath, chest pain and dry cough for few months. Neck veins were distended. No lymphadenopathy.
  67. Chest radiograph: greatly widened mediastinum with a smooth lobulated outline.
  68. Lateral chest film: anterior mediastinal mass. Fiberoptic bronchoscopy revealed a mucosal redness. Percutaneous transthoracic FNAC was inconclusive.
  69. CT scan of mediastinum: anterior mediastinal mass mainly to the right side.
  70. Diagnostic Anterior Mediastinotomy Large cell Lymphoma
  71. Take Home Message  The (forgotten compartment) is no longer (forgotten) with the availability of many efficient and safe diagnostic techniques like conventional cervical and video-mediastinoscopy and the extended cervical mediastinoscopy which can be done routinely with high level of safety and minimum morbidity and mortality.  The primary role of mediastinoscopy lies in the evaluation of paratracheal and subcarinal lymphadenopathy.  Anterior mediastinotomy , the Chamberlain procedure, offers access to the aortic window and the anterior mediastinum. 81

Editor's Notes

  1. The endotracheal tube is positioned at the left corner of the mouth, with the anesthesia equipment at the patients left side. The table should be level or slightly tilted foot downwards to reduce venous congestion. For left handed surgeon, the installation may be mirrored to the right side.
  2. Station 1 nodes are not routinely accessed by cervical mediastinoscopy. Station 1 nodes are located above the suprasternal notch.
  3. A horizontal line drawn tangential at the upper margin of the aortic arch delineates the lower border of station 2 nodes.
  4. Station 3 nodes are also not accessible by conventional cervical mediastinoscopy. Station 3A lymph nodes are located prevascular (in front of vena cava) and 3P lymph nodes are located in the upper paraesophageal region, above the tracheal bifurcation.
  5. The posterior subcarinal nodes (station 7p), the para-esophageal nodes (station 8), the inferior pulmonary ligament nodes (station 9) are not accessible by conventional media-stinoscopy.
  6. The subaortic nodes (station 5) and para-aortic nodes (station 6) cannot be biopsied through a standard cervical mediastinoscopy.
  7. A bolster is placed under the patients shoulders and the neck is extended.
  8. Operation room setup for conventional mediastinoscopy. The surgeon is standing at the head of the table.
  9. For mediastinoscopy, only few instruments are needed. Scalpel, dissection scissors, pickups, small retracting instrument, suction and cautery device, needle holder and biopsy forceps.
  10. Conventional mediastinoscope.
  11. A 3 cm transverse cervical incision is made one-finger breadth above the suprasternal notch.
  12. Illustration of the anatomy of this region
  13. Sharp dissection exposes the pretracheal muscles which are separated vertically in the midline to expose the anterior surface of the trachea. The thyroid isthmus is retracted superiorly and the tracheal surface is exposed just below the isthmus. One has to be careful not to avulse the inferior thyroid veins. These small veins can usually be avoided. In case of bleeding, they need to be ligated or electrocoagulated.
  14. Incision of the pretracheal fascia. The tissues are cleared down to the anterior surface of the trachea exposing the dense white pretracheal fascia which is incised and dissected off the trachea exposing the cartilaginous rings. At this point one should avoid to dissect downward into the mediastinum. It is easier to incise the pretracheal fascia just below the isthmus of the thyroid and then to carry down the dissection along the anterior surface of the trachea.
  15. The surgeon's middle finger is advanced along the pretracheal plane and blunt dissection is carried out along the anterior surface of the trachea down to the carina.
  16. The mediastinum is carefully palpated for the presence of nodal disease. This palpation is of extreme importance, pretracheal nodes are more easier palpated rather than being visualized. In many cases massive infiltration of the upper mediastinal nodes is mainly diagnosed by palpating them in the mediastinum!
  17. The finger is withdrawn and the mediastinoscope is advanced.
  18. The plane in front of the mediastinoscope is developed with the use of blunt dissection, using a metal sucker through the channel of the mediastinoscope. Small bleeding vessels can be coagulated. The tissue planes are developed to the level of the carina and both tracheobronchial angles. The left and right border of the trachea are dissected.
  19. To avoid and to handle major complications, it is important to visualize the anatomical landmarks such as the azygos vein, the right and left main bronchus and the first branch of the right pulmonary artery before biopsies are taken.
  20. The left recurrent nerve lies approximately 1 cm lateral to the trachea and can usually be visualized in the mid tracheal plane. From there it can be followed more distally.
  21. Sequentially, the paratracheal tissues are entered to expose the lymph nodes at the various stations. The lymph nodes lie outside of the fascial envelope and the pretrachial fascia has to be broken with the suction device (for instance in the subcarinal area and the lower paratracheal area) or by the finger (upper paratracheal and pretracheal area). When the mediastinoscope reaches the subcarinal area, a thin layer of firm fibrous tissue has to be broken to visualize the subcarinal nodes. Beneath the subcarinal nodes, the esophagus can be visualized. One has to be careful not to damage the esophagus.
  22. The biopsies are stored in separate vials, labelled with these adhesive labels and sent for pathology.
  23. When biopsies are taken from the different nodal stations the biopsy forceps is cleaned each time to prevent contamination and false positive results.
  24. Mediastinoscopy
  25. If the standard cervical mediastinoscopy is negative, a plane is developed anterior to the aortic arch, down to the subaortic space. To do so, blunt dissection is performed with the finger anterior to the innominate artery, between the innominate artery and the innominate vein. The mediastinoscope is introduced through the cervical incision above the aortic arch. The scope is advanced over the top of the aortic arch down to the aortopulmonary window.
  26. Biopsies of lymph nodes in the aortopulmonary window are taken.
  27. Repeat mediastinoscopy. Blunt dissection is started on the left side of the trachea. This region was usually not extensively dissected at the previous mediastinoscopy and thus containing less fibrosis.
  28. A left paratracheal tunnel is created (medial border is trachea, the surface is part of the esophagus) and the scope is inserted.
  29. Figure 39-5 Patient and equipment positioning for videomediastinoscopy. The surgeon is shown looking across the operative field at the video monitor. Diagram of a video mediastinoscope (top inset). View of the patient’s neck in extension, the incision site, and the support behind the patient’s shoulders (bottom inset).
  30. Figure 39-6 Anatomical structures at the high paratracheal level as seen from the surgeon’s position standing at the patient’s head. Ao, aorta; INNOM. A, innominate artery; LCCA, left common carotid artery; LSCA, left subclavian artery.
  31. Figure 39-7 View through the mediastinoscope at the high paratracheal level. Note the tracheal rings posteriorly, the innominate artery anteriorly, and the use of the suction cautery to dissect through the pretracheal fascia and allow the underlying station 2 lymph node located to the right of the trachea to bulge into the operative field.
  32. Figure 39-10 Anatomical structures at the lower paratracheal level as seen from the surgeon’s position standing at the patient’s head. RA, right atrium; RPA, right pulmonary artery; SVC, superior vena cava; AZYG V, azygous vein; E, esophagus; LSA, left subclavian artery; Ao, aorta; LIGAMENTUM ART, ligamentum arteriosum; LPA, left pulmonary artery.
  33. Figure 39-11 View through the mediastinoscope at the lower paratracheal level. Note the use of an aspirating needle to rule out a vascular structure before biopsy of the suspected lymph node.
  34. Figure 39-14 Anatomical structures at the carinal level as seen from the surgeon’s perspective standing at the patient’s head. RA, right atrium; RPA, right pulmonary artery; SVC, superior vena cava; AZYG V, azygous vein; E, esophagus; LSCA, left subclavian artery; Ao, aorta; LMB, left main bronchus.
  35. Figure 39-15 View through the mediastinoscope at the carinal level. Note the widened tracheal diameter and the triangular-shaped tracheal cartilage just proximal to the subcarinal tissue containing station 7 lymph nodes. After blunt dissection and needle aspiration, as described earlier, a nodal biopsy is illustrated with a cup biopsy forceps. RPA, right pulmonary artery; RMB, right main bronchus; LMB, left main bronchus.
  36. Figure 39-18 View of the mediastinoscope light transilluminating the right lower paratracheal region through the tracheal wall. Note the bronchoscope, which has been passed through the endotracheal tube, lying within the tracheal lumen. Inset shows a bronchoscopic view of the distal trachea and carina with bright transillumination of the right lower paratracheal wall from the mediastinoscope confirming the location of the mediastinal node station as that of 4R. Ao, aorta.
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