Mediastinum Examination

Mediastinoscopy

Procedure Overview

A mediastinoscopy is a surgical procedure performed to examine the mediastinum. The mediastinum is the space behind the sternum (breastbone) in the middle of the chest that separates the two lungs. It contains lymph nodes, the heart and its great vessels, the trachea, the esophagus, and the thymus gland.

The mediastinum can be visualized by the use of an endoscopic instrument called a mediastinoscope. A mediastinoscope is a lighted, long, thin, flexible tube that can visualize the organs and structures of the mediastinum. It also has the capacity to transmit images onto a TV-like monitor.

The procedure is performed in an operating room under general anesthesia. The surgeon makes a small incision in the neck above the top of the sternum and inserts the mediastinoscope. In addition to directly visualizing the mediastinum, tissue samples of mediastinal lymph nodes may be obtained. These lymph nodes receive lymphatic drainage from the lungs. A biopsy of these lymph nodes helps to identify disease processes that may be present in the mediastinum and the lungs.

The primary reason for mediastinoscopy is to visualize, examine, and biopsy lymph nodes for identification of disease processes in the mediastinum, particularly the staging of lung cancer. Determining the “stage” or the extent to which cancer has spread is important in planning the proper treatment. While positron emission tomography (PET scan) is becoming more useful in staging cancer, mediastinoscopy remains an important diagnostic tool when tissue biopsy is required.

Other related procedures that may be used to diagnose problems of the lungs and respiratory tract are chest X-ray, chest fluoroscopy, bronchoscopy, bronchography, chest ultrasound, lung scan, pleural biopsy, oximetry, pulmonary angiogram, pulmonary function tests, sinus X-ray, thoracentesis, computed tomography (CT scan) of the chest, and PET scan. Please see these procedures for additional information.

Respiratory System - Click to Enlarge

The respiratory system is made up of the organs involved in the interchanges of gases, and consists of the:

• Nose

• Pharynx

• Larynx

• Trachea

• Bronchi

• Lungs

The upper respiratory tract includes the:

• Nose

• Nasal cavity

• Ethmoidal air cells

• Frontal sinuses

• Maxillary sinus

• Larynx

• Trachea

The lower respiratory tract includes the lungs, bronchi, and alveoli.

The lungs take in oxygen, which cells need to live and carry out their normal functions. The lungs also get rid of carbon dioxide, a waste product of the body's cells.

The lungs are a pair of cone-shaped organs made up of spongy, pinkish-gray tissue. They take up most of the space in the chest, or the thorax (the part of the body between the base of the neck and diaphragm).

The lungs are enveloped in a membrane called the pleura.

The lungs are separated from each other by the mediastinum, an area that contains the following:

• The heart and its large vessels

• Trachea (windpipe)

• Esophagus

• Thymus

• Lymph nodes

The right lung has three sections, called lobes. The left lung has two lobes. When you breathe, the air enters the body through the nose or the mouth. It then travels down the throat through the larynx (voice box) and trachea (windpipe) and goes into the lungs through tubes called main-stem bronchi.

One main-stem bronchus leads to the right lung and one to the left lung. In the lungs, the main-stem bronchi divide into smaller bronchi and then into even smaller tubes called bronchioles. Bronchioles end in tiny air sacs called alveoli.

Reasons for the Procedure

A mediastinoscopy is primarily performed to visualize, examine, and biopsy lymph nodes to aid in determining the stage of lung cancer and potential surgical options. Conditions of the mediastinum that may be detected by mediastinoscopy may include, but are not limited to, the following:

• Cancer of the lungs, bronchi, and/or or structures in the mediastinum

• Infection or inflammation

• Lymphoma - a type of cancer in the lymphatic system; includes Hodgkin disease

• Sarcoidosis - a condition that causes small, fleshy, swellings in the tissue around organs, usually in the liver, lungs, and spleen

• Thymoma - a tumor of the thymus gland (located behind the breastbone, the thymus is part of the immune system)

By determining the stage of lung or mediastinal cancer, if present, the physician can plan for additional surgical procedures or other types of treatment.

There may be other reasons for your physician to recommend a mediastinoscopy.

Risks of the Procedure

As with any surgical procedure, complications can occur. Some possible complications may include, but are not limited to, the following:

• Bleeding

• Infection

• Temporary or permanent paralysis of the laryngeal nerve, which may cause hoarseness

• Pneumothorax - air becomes trapped in the pleural space causing the lung to collapse

• Subcutaneous emphysema - air under the skin

• Perforation of the esophagus (hollow, muscular tube used in swallowing), trachea (windpipe), or large blood vessels of the heart - rare

Mediastinoscopy may be contraindicated in certain situations, including, but not limited to, the following:

• Previous mediastinoscopy, heart surgery, or other chest surgery

• Pregnancy

• Previous neck or cervical spine surgery, or other conditions which would prevent proper positioning of the neck during the procedure

• Superior vena cava obstruction - blockage in the large vein that carries blood from the upper body into the heart

There may be other risks depending upon your specific medical condition. Be sure to discuss any concerns with your physician prior to the procedure.

Before the Procedure

• The physician will explain the procedure to you and offer you the opportunity to ask any questions that you might have about the procedure.

• You will be asked to sign a consent form that gives your permission to do the procedure. Read the form carefully and ask questions if something is not clear. More extensive surgery may be performed during the procedure if examination and biopsy results indicate the need for it. Your physician will explain this possibility to you during the consent process.

• In addition to a complete medical history, your physician may perform a complete examination to ensure you are in good health before undergoing the procedure. You may undergo blood tests or other diagnostic tests.

• You will be asked to fast for eight hours before the procedure, generally after midnight.

• If you are pregnant or suspect that you are pregnant, you should notify your physician.

• Notify your physician if you are sensitive to or are allergic to any medications, latex, iodine, tape, or anesthetic agents (local and general).

• Notify your physician of all medications (prescription and over-the-counter) and herbal supplements that you are taking.

• Notify your physician if you have a history of bleeding disorders or if you are taking any anticoagulant (blood-thinning) medication, aspirin, or other medications that affect blood clotting. It may be necessary for you to stop these medications prior to the procedure.

• You may receive a sedative prior to the procedure to help you relax.

• The area around the surgical site may be shaved.

• Based upon your medical condition, your physician may request other specific preparation.

A mediastinoscopy may be performed on an outpatient basis or as part of your stay in a hospital. The procedure will be performed while you are asleep under general anesthesia. Procedures may vary depending on your condition and your physician’s practices.

Click Image to Enlarge

Generally, a mediastinoscopy follows this process:

1. You will be asked to remove any jewelry or other objects that may interfere with the procedure.

2. You will be asked to remove clothing and will be given a gown to wear.

3. An intravenous (IV) line will be started in your arm or hand.

4. You will be positioned on the operating table lying on your back.

5. After you have been sedated, a breathing tube will be inserted into your lungs to assist your breathing while you are asleep during the procedure.

6. The anesthesiologist will continuously monitor your heart rate, blood pressure, breathing, and blood oxygen level during the surgery.

7. The skin over the surgical site will be cleansed with an antiseptic solution.

8. The physician will make a small horizontal incision just above the breastbone.

9. The physician will use a finger to make a passageway into the mediastinum and palpate (examine by touch) the lymph nodes.

10. The physician will advance the mediastinoscope through the passageway and examine the mediastinal structures. One or more tissue samples may be taken for biopsy.

11. After the examination has been completed and any other procedures performed, the mediastinoscope will be removed.

12. If more extensive surgery is indicated, the physician may choose to perform it at this time.

13. The incision will be closed with stitches or adhesive strips.

14. Tissue specimens will be sent to the lab for examination.

15. The breathing tube may be removed before you leave the operating room or later in the recovery room, depending on whether a more extensive procedure was performed.

After surgery, you will be taken to the recovery room for observation. Your recovery process will vary depending upon the type of anesthesia that is given, as well as the type of procedure that was performed. If a more extensive procedure was performed, your recovery process will take longer, and you will most likely be admitted to the hospital for a day or so.

The area of your incision will be monitored for bleeding. Once your blood pressure, pulse, and breathing are stable and you are alert, you will be taken to your hospital room or discharged to your home.

Your physician may order a chest X-ray after the procedure to check for bleeding or air in the pleural space.

Once you are home, it is important to keep the incision area clean and dry. Your physician will give you specific bathing instructions. If stitches are used, they will be removed during a follow-up office visit. If adhesive strips are used, they should be kept dry, and generally will fall off within a few days.

You may resume your normal diet unless your physician advises you differently.

Take a pain reliever for soreness as recommended by your physician. Aspirin or certain other pain medications may increase the chance of bleeding. Be sure to take only recommended medication.

Your physician may recommend using throat lozenges for a sore throat.

Notify your physician to report any of the following:

• Fever and/or chills

• Redness, swelling, or bleeding or other drainage from the incision site

• Increased pain around the incision site

• Any changes in voice or difficulty breathing

Your physician may give you additional or alternate instructions after the procedure, depending on your particular situation.