mediastinoscopy


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Related to mediastinoscopy: sarcoidosis, Chamberlain procedure

Mediastinoscopy

 

Definition

Mediastinoscopy is a surgical procedure that allows physicians to view areas of the mediastinum, the cavity behind the breastbone that lies between the lungs. The organs in the mediastinum include the heart and its vessels, the lymph nodes, trachea, esophagus, and thymus.
Mediastinoscopy is most commonly used to detect or stage cancer. It is also ordered to detect infection, and to confirm diagnosis of certain conditions and diseases of the respiratory organs. The procedure involves insertion of an endotracheal (within the trachea) tube, followed by a small incision in the chest. A mediastinoscope is inserted through the incision. The purpose of this equipment is to allow the physician to directly see the organs inside the mediastinum, and to collect tissue samples for laboratory study.

Purpose

Mediastinoscopy is often the diagnostic method of choice for detecting lymphoma, including Hodgkin's disease. The diagnosis of sarcoidosis (a chronic lung disease) and the staging of lung cancer can also be accomplished through mediastinoscopy. Lung cancer staging involves the placement of the cancer's progression into stages, or levels. These stages help a physician study cancer and provide consistent definition levels of cancer and corresponding treatments. The lymph nodes in the mediastinum are likely to show if lung cancer has spread beyond the lungs. Mediastinoscopy allows a physician to observe and extract a sample from the nodes for further study. Involvement of these lymph nodes indicates diagnosis and stages of lung cancer.
Mediastinoscopy may also be ordered to verify a diagnosis that was not clearly confirmed by other methods, such as certain radiographic and laboratory studies. Mediastinoscopy may also aid in certain surgical biopsies of nodes or cancerous tissue in the mediastinum. In fact, the surgeon may immediately perform a surgical procedure if a malignant tumor is confirmed while the patient is undergoing mediastinoscopy, thus combining the diagnostic exam and surgical procedure into one operation when possible.
Although still performed in 2001, advancements in computed tomography (CT) and magnetic resonance imaging (MRI) techniques, as well as the new developments in ultrasonography, have led to a decline in the use of mediastinoscopy. In addition, better results of fine-needle aspiration (drawing out fluid by suction) and core-needle biopsy (using a needle to obtain a small tissue sample) investigations, along with new techniques in thoracoscopy (examination of the thoracic cavity with a lighted instrument called a thoracoscope) offer additional options in examining mediastinal masses. Mediastinoscopy may be required, however, when these other methods cannot be used or when the results they provide are inconclusive.

Precautions

Because mediastinoscopy is a surgical procedure, it should only be performed when the benefits of the exam's findings outweigh the risks of surgery and anesthesia. Patients who previously had mediastinoscopy should not receive it again if there is scarring present from the first exam.
Several other medical conditions, such as impaired cerebral circulation, obstruction or distortion of the upper airway, or thoracic aortic aneurysm (abnormal dilation of the thoracic aorta) may also preclude mediastinoscopy. Anatomic structures that can be compressed by the mediastinoscope may complicate these pre-existing medical conditions.

Description

Mediastinoscopy is usually performed in a hospital under general anesthesia. An endotracheal tube is inserted first, after local anesthesia is applied to the throat. Once the patient is under general anesthesia, a small incision is made usually just below the neck or at the notch at the top of the breastbone. The surgeon may clear a path and feel the patient's lymph nodes first to evaluate any abnormalities within the nodes. Next, the physician will insert the mediastinoscope through the incision. The scope is a narrow, hollow tube with an attached light that allows the surgeon to see inside the area. The surgeon can insert tools through the hollow tube to help perform biopsies. A sample of tissue from the lymph nodes or a mass can be extracted and sent for study under a microscope or on to a laboratory for further testing.
In some cases, analysis of the tissue sample which shows malignancy will suggest the need for immediate surgery while the patient is already prepared and under anesthesia. In other cases, the surgeon will complete the visual study and tissue extraction and stitch the small incision closed. The patient will remain in the surgery recovery area until it is determined that the effects of anesthesia have lessened and it is safe for the patient to leave the area. The entire procedure should take about an hour, not counting preparation and recovery time. Studies have shown that mediastinoscopy is a safe, thorough, and cost-effective diagnostic tool with less risk than some other procedures.

Preparation

Patients are asked to sign a consent form after having reviewed the risks of mediastinoscopy and known risks or reactions to anesthesia. The physician will normally instruct the patient to fast from midnight before the test until after the procedure is completed. A physician may also prescribe a sedative the night before the exam and before the procedure. Often a local anesthetic will be applied to the throat to prevent discomfort during placement of the endotracheal tube.

Aftercare

Following mediastinoscopy, patients will be carefully monitored to watch for changes in vital signs or indications of complications of the procedure or the anesthesia. A patient may have a sore throat from the endotracheal tube, temporary chest pain, and soreness or tenderness at the site of incision.

Risks

Complications from the actual mediastinoscopy procedure are relatively rare—the overall complication rate in various studies has been 1.3-3.0%. However, the following complications, in decreasing order of frequency, have been reported:
Mediastinoscopy is a surgical procedure used to detect or stage lymphoma or lung cancer. In this procedure, the surgeon makes an incision below the neck and inserts a mediastinoscope (a narrow, hollow tube with an attached light) through it to reach the area behind the breastbone. The surgeon can then insert tools through the scope to collect tissue for laboratory analysis.
Mediastinoscopy is a surgical procedure used to detect or stage lymphoma or lung cancer. In this procedure, the surgeon makes an incision below the neck and inserts a mediastinoscope (a narrow, hollow tube with an attached light) through it to reach the area behind the breastbone. The surgeon can then insert tools through the scope to collect tissue for laboratory analysis.
(Illustration by Electronic Illustrators Group.)
  • hemorrhage
  • pneumothorax (air in the pleural space)
  • recurrent laryngeal nerve injury, causing hoarseness
  • infection
  • tumor implantation in the wound
  • phrenic nerve injury (injury to a thoracic nerve)
  • esophageal injury
  • chylothorax (chyle—a milky lymphatic fluid—in the pleural space)
  • air embolism (air bubble)
  • transient hemiparesis (paralysis on one side of the body)
The usual risks associated with general anesthesia also apply to this procedure.

Normal results

In the majority of procedures performed to diagnose cancer, a normal result involves evidence of small, smooth, normal-appearing lymph nodes and no abnormal tissue, growths, or signs of infection. In the case of lung cancer staging, results are related to the severity and progression of the cancer.

Abnormal results

Abnormal findings may indicate lung cancer, tuberculosis, the spread of disease from one body part to another, sarcoidosis (a disease that causes nodules, usually affecting the lungs), lymphoma (abnormalities in the lymph tissues), and Hodgkin's disease.

Resources

Books

Fischbach, Frances Talaska. A Manual of Laboratory and Diagnostic Tests. 6th ed. Philadelphia: Lippincott Williams and Wilkins, 2000.
Pagana, Kathleen Deska, and Timothy James Pagana. Mosby's Manual of Diagnostic and Laboratory Tests. St. Louis, MO: Mosby, 1998.

Periodicals

Deslauriers, Jean, and Jocelyn Gregoire. "Clinical and Surgical Staging of Non-Small Cell Lung Cancer." Chest, Supplement (April 2000): 96S-103S.
Tahara R. W., et al. "Is There a Role for Routine Mediastinoscopy in Patients With Peripheral T1 Lung Cancers?" American Journal of Surgery December 2000: 488-491.

Organizations

Alliance for Lung Cancer Advocacy, Support, and Education. P.O. Box 849, Vancouver, WA 98666. (800) 298-2436. http://www.alcase.org.
American Cancer Society. 1599 Clifton Rd. NE, Atlanta, GA 30329. 800-ACS-2345 http://www.cancer.org.
American Lung Association. 1740 Broadway, New York, NY 10019-4374. 800-LUNG-USA (800-586-4872). http://www.lungusa.org.

Key terms

Endotracheal — Placed within the trachea, also known as the windpipe.
Hodgkin's disease — A malignancy of lymphoid tissue found in the lymph nodes, spleen, liver, and bone marrow.
Lymph nodes — Small round structures located throughout the body; contain cells that fight infections.
Pleural space — Space between the layers of the pleura (membrane lining the lungs and thorax).
Sarcoidosis — A chronic disease characterized by nodules in the lungs, skin, lymph nodes and bones; however, any tissue or organ in the body may be affected.
Thymus — An unpaired organ in the mediastinal cavity that is important in the body's immune response.

mediastinoscopy

 [me″de-as″tĭ-nos´kah-pe]
examination of the mediastinum by means of an endoscope inserted through an anterior midline incision just above the thoracic inlet.

me·di·as·ti·nos·co·py

(mē'dē-as'ti-nos'kŏ-pē),
Endoscopic examination of the mediastinum through a suprasternal incision, usually for biopsy of paratracheal lymph nodes.
[mediastinum + G. skopeō, to view]

mediastinoscopy

(mē′dē-ăs′tə-nŏs′kə-pē)
n.
Exploration of the mediastinum through a suprasternal incision.

mediastinoscopy

A procedure in which an endoscope is inserted into the mediastinum, and regional structures (lungs and lymph nodes) are visualised to evaluate and/or manage neoplasms or other lesions.

Indications
Widened mediastinum of unknown cause, staging of a known cancer, confirmation of TB or sarcoidosis, diagnosis of mediastinal fibrosis.
 
Types
Cervical mediastinoscopy (for right paratrachial and subcarinal LNs); anterior mediastinoscopy (for left mediastinum, especially in presence of left upper lobe lesions); anterior mediastinotomy (on either side).
 
Complications
< 3%; haemorrhage, pneumothorax, vocal cord paralysis, oesophageal perforation.

mediastinoscopy

Surgery A procedure in which an endoscope is inserted in the mediastinum, and regional structures—lungs and lymph nodes are visualized to detect neoplasms or other lesions needing evaluation or therapy; mediastinoscopy may be part of a 'staging procedure', where a Pt has a known malignancy, and metastases are identified to determine further management Indications Widened mediastinum of unknown cause, cancer staging, confirmation of TB or sarcoidosis, diagnosis of mediastinal fibrosis Types Cervical mediastinoscopy–for right paratrachial and subcarinal LNs; anterior mediastinoscopy–for left mediastinum, especially in presence of left upper lobe lesions; anterior mediastinotomy–on either side Complications < 3%; hemorrhage, pneumothorax, vocal cord paralysis, esophageal perforation. See Endoscopy, Mediastinotomy, Thoracotomy.

me·di·as·ti·nos·co·py

(mē'dē-as'ti-nos'kǒ-pē)
Exploration of the mediastinum through a suprasternal incision, for biopsy of paratracheal lymph nodes.
[mediastinum + G. skopeō, to view]

mediastinoscopy

Direct examination by fibreoptic ENDOSCOPY of the internal structures of the central compartment of the chest (the MEDIASTINUM). The endoscope is passed through an opening in the base of the neck under general anaesthesia. The procedure is relatively easy on the right side but is more difficult and dangerous on the left and other methods are often preferred.
References in periodicals archive ?
In the past patient suspected to have sarcoidosis with negative transbronchial biopsy were referred for mediastinoscopy, the availability of EBUS TBNA is a less Invasive safe and more economical alternative for obtaining a pathologic diagnosis of mediastinal lymph nodes.
Videoassisted mediastinoscopy (VAM) for surgical resection of ectopic parathyroid adenoma.
Schafers, "Mediastinal lymph node staging in suspected lung cancer: comparison of positron emission tomography with F-18-fluorodeoxyglucose and mediastinoscopy," Annals of Thoracic Surgery, vol.
Patients without a specific diagnosis at EBUS-TBNA (benign or malignant) but a definitive non-malignant diagnosis at mediastinoscopy were considered false negative.
Subsequent to treatment, lymphoma size decreased progressively, relieving the airway compression, and extubation was performed after one week from undergoing the mediastinoscopy. After three days of observation, she was discharged home, with scheduled outpatient chemotherapy sessions and later possible surgical management.
The most important factor that contributed to such high rates was that there was no false negative results in case of mediastinoscopy. The reason for this was that utmost effort was shown for taking biopsies from all the MLNs that can be seen by dissecting all the MLN stations routinely that can be reached during mediastinoscopy.
If disease was suspected but not confirmed, patients underwent further radiological follow up (thoracoscopy, thoracotomy, or mediastinoscopy and CT-guided biopsy) after 6 months.
As the gold standard for primary lymph node staging,[sup][10],[11] mediastinoscopy was not recommended in patients with peripheral tumors and negative mediastinal PET images, because it is not cost effective for patients with clinical stage N0 NSCLC,[sup][12] and direct surgical resection with systematic nodal dissection is indicated for tumors ≤3 cm located in the outer third of the lung.[sup][13] CT has been used to assess lymph node status and in the lung cancer screening program.
These include minimally invasive transthoracic or transbronchial fine needle aspiration cytology (FNAC) or core needle biopsy (CNB), mediastinoscopy, video-assisted thoracoscopy, and open surgical biopsy.
Lymph node exploration by fine needle aspiration and mediastinoscopy was inconclusive and the decision for surgery was made by the multidisciplinary team.
Liberman, "Mediastinal staging: endosonographic ultrasound lymph node biopsy or mediastinoscopy," Thoracic Surgery Clinics, vol.
[6] Since the advent of CT and MRI, a decline in the use of other diagnostic chest procedures such as chest fluoroscopy, tomography, mediastinoscopy, arteriography, and thoracotomy has occurred.