Ann Thorac Surg 2008;86:1704-1706. doi:10.1016/j.athoracsur.2008.04.017
© 2008 The Society of Thoracic Surgeons
How To Do It
Extended Mediastinoscopic Examination at the Right Hilum
Chang Chen, MD*,
Yi-ming Zhou, MD
Department of General Thoracic Surgery, Tongji University-Affiliated Shanghai Pulmonary Hospital, Shanghai, China
Accepted for publication April 7, 2008.
* Address correspondence to Dr Chen, Zhengmin Rd. 507, Shanghai, 200433, China (Email: changchenc{at}hotmail.com).
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Abstract
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Transcervical video-assisted mediastinoscopy has been the gold standard for mediastinal lymph node sampling. However, we believe that its application at the hilum region has not been previously documented. The current study details this technique and discusses its advantages and potential applications.
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Introduction
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Video-assisted mediastinoscopy (VAM) has been regarded as the gold standard for mediastinal biopsy. Its scope is usually limited to station-1 (highest mediastinal) to station-7 (subcarinal) lymph nodes, either through cervical or anterior routes [1–4]. We believe that there have been no previous experiences of hilar (station 10) mediastinoscopic examination reported, because video-assisted thoracoscopy is usually preferred. However, when indicated, extended VAM examination at the right hilum region is also a practical option and offers several advantages, including being mini-invasive, increasing histologic yield, and avoiding operation conversion to thoracoscopic or open biopsy.
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Technique
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The study was approved by the Ethics Committee of Shanghai Pulmonary Hospital in January 2006, and informed consent was obtained from all patients.
Patients
Twelve patients were involved in this study. Our initial VAM experiences were derived from 2 patients whose computed tomographic scans suggested only limited mediastinal lymph node enlargement (one station involved) and prominent right hilar lymphadenopathy. Although the initial output from mediastinal biopsies was negative, histologic diagnosis was successfully obtained from hilar lymph nodes. For these 2 patients, VAM was preferred over thoracoscopy primarily because of its less invasive nature and better record of postoperative recovery.
Based on these preliminary experiences, we expanded the study to verify the operative feasibilities in an additional 10 patients. The operative field was marked with clips in 3 patients with left-sided cancer and bi-hilar lymph enlargement; in these cases the operative margin at the right hilum was marked for subsequent radiotherapy. The inclusion criteria for the other 7 patients were right open thoracotomy candidates with right lung cancer who received VAM examination for enlarged left mediastinal lymph nodes (L2–L4).
Surgical Technique
All operations were performed under general anesthesia. A routine suprasternal 2-cm incision was made. Lymph nodes from stations 2, 3, 4 and 7 were exposed with the blunt-tipped suction coagulation device and sampled. Before the right hilum was entered, adhesions at the right tracheobronchial angle were dissected to facilitate instrumental manipulation. The right pulmonary artery trunk was then exposed caudally to the azygous vein in front of right main bronchus. It was usually not mandatory to expose a clear margin of the azygous vein; yet the other two structures (ie, the pulmonary artery and the right main bronchus) should be visualized and carefully manipulated as landmarks during the whole procedure. The main techniques for exposing the right hilum were dissecting the para-bronchial tissue plane with the suction device, followed by a "diving" maneuver using the scope tip. In this way the scope could be advanced further along the right main bronchus until it reached the bifurcation of the right upper and lower artery branches. This vessel bifurcation usually appeared at the right-upper corner on the monitor. When the upper artery branch was further displaced superiorly with the scope tip, the hilar nodes were visible between the pulmonary artery branches and the right upper bronchus (Figs 1A,
1B). Caution should be taken not to overstretch the artery at this point, in case of vessel injury or even rupture. Biopsies were then taken and submitted for frozen section. In radiation candidates, a clip was placed on the cancer-containing field. Occasionally a minor bronchial artery might be encountered adjacent to the pulmonary artery branch; homeostasis could be easily accomplished with coagulation. The patient's neck wound was then closed without drainage after an adequate amount of tissue was sampled.
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Fig 1. (A, B) Mediastinoscopic view of the hilar anatomy. Note the lymph node located between the pulmonary artery (PULM A.) branches and right upper bronchus. (AZYGOUS V. = azygous vein; LN = lymph node (#10); R. BRONCHUS = right bronchus; RB = right middle bronchus; RPA = right pulmonary artery; RUB = right upper bronchus; RUPA = right upper pulmonary artery branch; Superior PULM V. = superior pulmonary vein.)
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When tissues around the middle bronchus must be examined, the scope may be advanced further along the right main bronchus, underneath the right lower pulmonary artery. The lymph node between the right upper and middle bronchus is defined as station 11, according to Naruke's mapping.
Histologic Yield of Hilar Lymph Nodes
Frozen sections confirmed the hilar nodes to be lung cancer in the first patient and granulatous tissue in the second patient. The VAM-sampled hilar nodes were confirmed as metastasized cancer in 6 of the remaining 10 patients, but were unrevealing in the others.
Intraoperative Findings
Slight stress on the pulmonary artery branches, due to pressure from the scope tip, was noted during VAM procedures, yet no bleeding or vessel bruising occurred secondary to such strains. As well, the arteries appeared normal in color and the wall integrity was noted as well preserved under re-examination during open thoracotomies, and no obvious signs of vessel injuries were present.
VAM Operative Field Verification
Postoperative chest films and chest computed tomographic scans demonstrated that the hilar nodes under examination were station 10 (Figs 2A,
2B). The number 11 node may be reached adjacent to the right middle bronchus (Fig 2C).
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Fig 2. Postoperative chest film (A) and computed tomographic image (B) demonstrate the clip at the right hilum, adjacent to the cancerous lymph node. (C) The clip marks the position of a #11 node between the right upper and middle bronchus. The arrows point to the metal clip at the hilum.
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Postoperative Outcomes
No complications occurred and all 12 patients were ambulant on postoperative day 1. The first patient was referred to the radiological department for cranial radiation on postoperative day 1. However, this patient had epilepsy develop on the same day that he was relieved by prompt dehydration and radiation. The second patient was diagnosed with sarcoidosis and was referred to the respiratory department. The left cancer patients, who had mediastinal and contralateral hilar nodal involvement, received chemoradiation as preoperatively scheduled. Both the hilum and mediastinum were included in the radiation schedule.
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Comment
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Mediastinoscopy has proved to be safe, effective, and mini-invasive for mediastinal biopsy. The mediastinal lymph nodes that can be normally accessed include stations 1 to 4 and 7 by suprasternal incision [1–3], and stations 5 to 6 by the parasternal route [4]. Although from an anatomical view, the para-hilar region is also reachable [5], mediastinoscopic examination at the hilum region has been previously omitted.
The practical consideration in performing extended VAM at the hilum region is that the procedure widens the extent of sampling and increases the positive yield rate. When a nodule is located among the right bronchus, the inferior pulmonary artery branch, and the superior pulmonary vein (Fig 1B), biopsy may be difficult even for open surgery. However, this situation can be satisfactorily solved with the present technique, a backup maneuver for para-bronchus tissue biopsy. The use of this technique can also effectively avoid operation conversion to thoracoscopic or thoracotomic biopsy. Moreover, providing a pathologic view of the N1 status of lung cancer is another minor benefit. Although it is yet unnecessary to confirm N1 disease in surgical candidates, it may benefit some nonoperable cancer patients. The cancerous field can be well-delineated for subsequent radiation, as described in the present cases. In addition, when percutaneous needle biopsy and bronchoscopic examinations fail to make pathologic diagnosis, sampling of enlarged N1 nodes may be an alternative choice.
One of the most important questions to be addressed is whether such a procedure should be advocated over another mini-invasive technique for hilar biopsy (ie, video-assisted thoracoscopy). Video-assisted mediastinoscopy has several advantages, as Gossot and colleagues [6] observed. First, the thoracic cavity is not entered during VAM, so the procedure is not hampered by pleural adhesions, intraoperative anesthetic manipulations are simple, and the operation is safe in candidates with impaired pulmonary function. Second, VAM requires only one short incision, so it has cosmetic benefits and is associated with less postoperative pain. Third, there is no postoperative chest tube required after VAM examination; all VAM patients can be discharged early and safely. Additional advantages are a lower operative complication rate, fewer postoperative respiratory problems, and less of a postoperative nursing burden [6].
Endobronchial ultrasound-guided transbronchial needle aspiration has recently been advocated as a promising alternative for accessing both mediastinal and hilar lymph nodes [7, 8], and its sensitivity and specificity may even reach 98.7% and 100%, respectively [7]. However, this technique is currently and largely limited by resource availability, practitioner experience, and access to cytopathologists in most hospitals. In such a clinical setting, mediastinoscopy remains the gold standard for mediastinal lymph node biopsy, and the presently described technique certainly has practical value.
The current study made no attempt in the left hilum. The main obstacle to this is the position of the aorta, which makes biopsy of the left parabronchial nodes difficult. In this case, Endobronchial ultrasound-guided transbronchial needle aspiration or thoracoscopy is the better approach.
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References
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Abstract
Introduction
