What is the sphenopalatine ganglion?
The sphenopalatine ganglion (SPG) is a collection of nerve cells that is closely associated with the trigeminal nerve, which is the main nerve involved in headache disorders. It contains autonomic nerves and sensory nerves. Autonomic nerves are specialized nerves that control organ functions, including gut and bladder movements, beating of the heart, sweating, salivation, tearing and other secretions. In the SPG, these autonomic nerves supply the lacrimal glands (which produces tears) and the inner lining of the nose and sinuses (which produces nasal discharge or congestion). The SPG is located just behind the bony structures of the nose.
What is the role of the sphenopalatine ganglion in headache disorders?
The SPG has connections to the brainstem, where cluster headaches and migraine attacks may be generated, and to the meninges (coverings of the brain) by the trigeminal nerve. Inflammation and opening of the blood vessels around the meninges occur, which activate pain receptors that send pain impulses through the trigeminal nerve, eventually to the sensory area of the brain, and are perceived as pain. In migraines, cluster headaches and other headache disorders, nerves carrying these pain signals pass through the SPG, with some making connections to the autonomic nerves. This explains why in cluster headaches, and sometimes in migraines we see autonomic features including tearing of the eyes and nasal congestion or discharge. We call this the trigeminal autonomic reflex.
What is a sphenopalatine ganglion block?
A nerve block is a procedure to stop pain transmission through the application of anesthesia to the nerve. In a sphenopalatine ganglion block, an anesthetic agent is administered to the collection of nerves in the ganglion. The least invasive way to access the SPG is through the nose.
Are there any risks to a sphenopalatine ganglion block?
The risks of the procedure are typically minimal. They include mild discomfort during the procedure, tearing during the procedure, a numb sensation when swallowing, bitter taste from the anesthesia, bleeding from the nose, and light-headedness. These side effects are uncommon and typically resolve within minutes to a few hours if they should occur.
Will I experience pain during a sphenopalatine ganglion block?
The procedure is painless. You may experience mild discomfort as the applicators are placed in the nostrils, tearing during the placement and possibly a bitter taste from the anesthetic agent. These symptoms typically resolve rapidly after block placement.
How often can I have this procedure done?
SPG block can be repeated as often as needed to reduce pain. One study report reduced frequency and severity of chronic migraine pain over a six month period if the procedure was done twice a week for six weeks (a total of 12 procedures).
What conditions can be treated by a sphenopalatine ganglion block?
- Cluster headache
- Trigeminal neuralgia
- Herpes zoster
- Paroxysmal hemicrania
- Pain from cancer of the head or neck
- Atypical facial pain
- Complex regional pain syndrome (CRPS)
- Vasomotor rhinitis
- Post-Dural puncture headache