Mediastinoscopy is a technique that allows you to visually examine the inside of the mediastinum, the region of the chest located between the two lungs, from a small incision in the neck, without having to open the rib cage. It also allows biopsies to be taken.

Mediastinoscopy is an endoscopy of the mediastinum. It allows direct visual examination of the organs located between the two lungs, in particular the heart, the two main bronchi, the thymus, the trachea and the esophagus, large blood vessels (the ascending aorta, the pulmonary arteries, the vein superior vena cava, etc.) and a number of lymph nodes. 

Most mediastinoscopy involves the lymph nodes. Indeed, x-rays, scans and MRIs can show that they have gained volume, but they do not allow us to know if this adenomegaly is due to an inflammatory pathology or a tumor. To decide, you have to go and see, and possibly take one or more lymph nodes to be analyzed in the laboratory. More generally, mediastinoscopy is used to inspect the suspicious masses that an imaging test has identified in the mediastinum and, if necessary, to make a biopsy.

Rather than opening the rib cage for this visual check, mediastinoscopy uses a probe called a mediastinoscope. This hollow tube, fitted with optical fibers and through which small surgical instruments can be passed, is introduced into the thorax through an incision of a few centimeters made at the base of the neck.

This surgical procedure is purely diagnostic. It is recommended after conventional medical imaging techniques (x-rays, CT scan, MRI) when these reveal suspicious masses in the mediastinum. It allows: 

to rule on the nature of the lesions. Lymph nodes in the mediastinum can, for example, be swollen in response to an infection such as tuberculosis or sarcoidosis, but also be affected by lymphoma (cancer of the lymphatic system) or by metastases from other cancers (of the lung , breast or esophagus in particular);

to take samples of tissues or lymph nodes, in case of doubt about the malignancy of a tumor or to clarify the diagnosis. These biopsies, analyzed in the laboratory, make it possible to establish the type of tumor, its evolutionary stage and its extension;

to follow the evolution of certain lung cancers, located on the external part of this organ, therefore visible from the mediastinum.

More and more, mediastinoscopy is being replaced by new, less invasive diagnostic techniques: the PET scan, which makes it possible, by combining the injection of a radioactive product with a scanner, to diagnose certain cancers or to search for metastases; and / or ultrasound-guided transbronchial biopsy, which involves passing a small needle through the mouth and then the bronchi to puncture a lymph node located on the other side of a bronchial wall. This last technique, which does not require any incision, is now allowed by the development of theultrasound bronchoscopy (use of a very flexible endoscope, fitted with a small ultrasound probe at its end). But the substitution of mediastinoscopy by these two techniques is not always possible. It depends in particular on the location of the lesion. 

Likewise, mediastinoscopy is not applicable in all situations. If the biopsy lesions are also inaccessible in this way (because they are located on an upper pulmonary lobe, for example), the surgeon must opt ​​for another surgical procedure: the mediastinotomy, that is to say the surgical opening of the mediastinum, or thoracoscopy, endoscopy of the thorax this time passing through small incisions between the ribs.

Even though it is a diagnostic test, mediastinoscopy is a surgical act. It is therefore performed by a surgeon, in the operating theater, and requires hospitalization of three or four days.

After general anesthesia, a small incision is made at the base of the neck, in the notch above the breastbone. The mediastinoscope, a long rigid tube fitted with a lighting system, is introduced through this incision and descended into the mediastinum, following the trachea. The surgeon can then examine the organs there. If necessary, he introduces other instruments through the endoscope to perform a biopsy, for laboratory analysis. Once the instrument is removed, the incision is closed with absorbable suture or biological glue.

This exam lasts about an hour. Discharge from hospital is scheduled for the next day or two, once surgeons are satisfied that there are no complications.

The visual and histological information provided by mediastinoscopy makes it possible to orient the therapeutic strategy. This depends on the pathology diagnosed. 

In the event of cancer, the treatment options are multiple, and depend on the type of tumor, its stage and its extension: surgery (removal of the tumor, removal of part of the lung, etc.), chemotherapy, radiotherapy, immunotherapy or a combination of several of these options.

In the event of metastasis, treatment is part of the treatment plan for the primary tumor.

If it is inflammation or infection, the exact cause will be investigated and treated.

Complications from this examination are rare. As with any operation, there is a low risk of a reaction to the anesthesia, bleeding and bruising, infection or healing problems. There is also a rare risk of damage to the esophagus or pneumothorax (injury to the lungs causing air to leak into the pleural cavity).

The laryngeal nerve can also be irritated, causing temporary paralysis of the vocal cords, resulting in a change in voice or hoarseness, which can last for a few weeks.

Pain is also felt in the first days after the operation. But prescribed painkillers work. Normal activities can be resumed very quickly. As for the small scar, it fades a lot within two or three months.