mediastinoscopy
Meaning of mediastinoscopy: A short operation through a small cut above the breastbone, giving direct access to the lymph nodes lying around the windpipe.
Definition of mediastinoscopy
Mediastinoscopy is a procedure in which a lighted tube is passed through a small incision just above the breastbone and advanced downward alongside the windpipe into the space between the lungs. It is carried out under general anesthesia. The usual purpose is to take samples from the lymph nodes there, most often to establish whether a lung cancer has spread beyond its origin.
What is being looked at?
The mediastinum, the central compartment of the chest lying between the two lungs. It is crowded: the heart and the great vessels leaving it, the windpipe and its first branches, the esophagus, the thymus and several major nerves all pass through it, packed in loose tissue along with clusters of lymph nodes. Those nodes drain the lungs, so whether they contain tumor cells decides how far a lung cancer has spread and therefore what treatment makes sense. The instrument used is a mediastinoscope, a rigid tube carrying a light and a channel for taking tissue.
What does it reach, and what does it miss?
| Node group | Reached from the neck incision? |
|---|---|
| Beside the upper windpipe, both sides | Yes |
| Where the windpipe divides | Yes |
| Beside the aorta and in front of it | No; needs a different route |
| Deep within the lung tissue itself | No |
The claim that the operation samples nodes on one side of the chest is a common error. From a single cut above the breastbone the surgeon works down the front and both sides of the windpipe, so both sides are accessible. What lies out of reach is the pocket beside the aortic arch, which is approached instead through a small opening in the front of the chest or with a camera passed between the ribs.
What are the risks and the alternatives?
The tube travels within a few millimeters of the largest vessels in the body, so bleeding is the serious hazard, though an uncommon one. The nerve that supplies the voice box hooks around structures on the left and runs close by, and injuring it leaves a hoarse voice. Tearing the lining of a lung can let air into the chest. Much of the sampling of lymph nodes that once required this operation is now attempted first with a needle passed through the wall of the airway under ultrasound guidance, which needs no incision, and the operation is kept for cases where that returns nothing useful.
Used in a sentence
Mediastinoscopy was performed to sample the lymph nodes before surgery was planned.
Good to know
The approach from above the breastbone reaches nodes on both sides of the windpipe and beneath its division but not those beside the aorta, which need a separate route, and the nerve supplying the voice box runs close enough that hoarseness is a recognized complication.
Word origin
Where “mediastinoscopy” comes from
Mediastinum derives from Latin words meaning standing in the middle, describing the space between the lungs, and -scopy comes from the Greek skopein, meaning to look at.