The sphenopalatine ganglion (SPG) is a collection of nerves (sympathetic, parasympathetic and some sensory). It lies in a bony cavity called the pterygopalatine fossa, which is deep in the midface.
It supplies the lacrimal gland, paranasal sinuses, glands of the mucosa of the nasal cavity and pharynx, the gingiva, and the mucous membrane and glands of the hard palate. It is not involved in feeling or movement.
Sometimes after a nerve is sensitized by trauma, infection or other causes, the sympathetic activity can cause pain. Blocking the sympathetic activity by anesthetizing the SPG may stop the pain.
A sphenopalatine ganglion block is done to:
- Diagnose the cause of pain in the face and head
- Manage the pain of certain types of chronic headaches
- Manage sympathetically maintained facial pain
The Sphenopalatine Ganglion Block Procedure
During a sphenopalatine ganglion block, pain-relieving medicine is injected to the region where the ganglion lies. This may reduce the release of the chemical norepinepherine activating the pain sensitive nerves and reduce the pain.
The patient is usually sedated, and using X-ray (fluoroscopy) guidance, a fine needle is placed near the SPG and anesthetic is injected. The patient will not feel numbness in the face. Pain relief may also not be immediate. A pain diary is used following the procedure to track the response.
The animation below shows how a sphenopalatine ganglion block is done.