Migraines a common ailment found in every 5 out of 10 people in the world. A migraine which starts with a normal headache and gradually increases the pain with common symptoms like throbbing and pulsating pain on one side of the head, feeling of nausea and vomiting, sensitivity to light, sound and odours, dizziness etc. There are many types of migraines and each type has a different treatment to prevent and cure the migraine headaches.
Over the period, many studies were conducted and a lot of treatments for migraines are available in the form of medications, surgical implant electrodes, neurostimulators, other types of therapies etc.
However in recent times, researchers have introduced Sphenopalatine Ganglion Block (SPG). It has been creating interest as an alternative extracranial nerve block which can be used as a part of treatment for a migraine.
What is Sphenopalatine Ganglion?
The sphenopalatine ganglion (SPG) is a collection of nerve cells that is closely associated with trigeminal nerve, which is the main nerve involved in the headache conditions. A sphenopalatine ganglion (SPG) also called as pterygopalatine ganglion, Meckel’s ganglion, Nasal ganglion is situated in the pterygopalatine fossa, located behind the bony structures of the nose. The SPG contains autonomic nerves and sensory nerves.
In SPG, the autonomic nerves which are specialized nerves control the functioning of the organs which stream the lacrimal glands (produce tears) and the inner lining of the nose and sinuses (produces nasal discharge and congestion). The SPG has connections to the brainstem and to the meninges (layers of the brain) by the trigeminal nerve. When there are an opening and swelling of the blood vessels around the meninges then the pain receptors are activated which will send pain instincts over the trigeminal nerve and then sensory part of the brain which is observed as pain.
When the cluster headaches and migraine attack occurs the nerves carrying these pain signals pass through the SPG and create connections to the autonomic nerves. The SPG is fundamental for facilitating the autonomic signs included such as tearing of eyes and nasal congestion which is produced by prime headache conditions, mostly the trigeminal autonomic cephalalgia (pain in the head).
How does Sphenopalatine Ganglion Block (SPG) work for Migraine?
An SPG block is a process to stop the pain diffusion through anesthesia to the nerve. The SPG block is an application of local anesthesia on to the collection of nerves in the ganglion. An SPG block may be performed to the patients experiencing pain due to acute or chronic migraines, acute cluster headaches and with other variant facial neuralgia’s.
To access the SPG, the most invasive method is through the nose. In the Sphenopalatine Ganglion block process the patient is instructed to lie on his/her back with the head slanted back to the side where the pain is, then a nasal anesthetic spray may be given to reduce any discomfort during the procedure.
The Sphenopalatine ganglion blockade can be performed by inserting a small applicator or catheter through the nostril to the back of the nasal cavity and by applying an anesthetic soaked cotton swab tipped applicator or catheter which drops onto the back of the nasal cavity, is immersed through the bone and into the SPG. Usually, the process takes approximately 5 minutes but the catheter is left there for up to 10-15 minutes.
The procedure of SPG block can be repeated in the other nostril depending on the type of headache condition to be treated. The time duration of the pain is not constant after the process, for some patients it will be some days to weeks and some other patients they will not respond to this process. After the process is done, the patient is asked to lay quietly for some time to observe the effectiveness of the block. Then the patient is asked to come to a sitting position and again to standing position once the patient is ready.
Below video demonstrates SPG block procedure on a patient
Sphenopalatine ganglion catheters were developed such as Sphenocath, Tx360, and Allevio devices which are helpful to the patients for a faster and a comfortable process.
SPG blocks are used to treat the following conditions
- Acute and chronic migraines
- Acute and cluster headaches
- Trigeminal neuralgia
- Cancer of the head and neck
- Paroxysmal hemicranias
- Facial neuralgia
- Nasal contact point headache
Safety measures and risks of SPG block
Sphenopalatine Ganglion Block (SPG) is not to be executed to the patients who have an infection in the upper respiratory tract, fever, bleeding problems, allergy to the anesthesia and pregnancy. For the treatment, there are protocols which implicate repeated injections. Depending on the patient condition the regularity of the injections taken will be analyzed.
Using the block, there are few minimal risks and possible complications of the process which include discomfort during and after the process, hypo-tension, nosebleed, infection, numb sensation when swallowing, bitter taste from anesthesia, light headedness, seizures and allergic reactions.
Sphenopalatine ganglion block side effects and complications are very rare and if arise then it will be resolved within minutes to a few hours. But, the procedure is safe, painless and is very effective than with older techniques.
What is Sphenopalatine Ganglion Stimulation?
Recently, a device that manages to decrease the pain of a migraine and cluster headaches has been developed. This device is called Sphenopalatine Ganglion Stimulation. In some studies it has shown that SPG stimulation may be effective, further studies are ongoing. The SPG stimulator is a miniature device and is implanted through the mouth into an area just behind the cheek under the anesthesia. There are no external wires or batteries. The SPG stimulator looks like a small cellphone which is placed next to the patient`s cheek and the patient controls the stimulation which gives electric current.
In one study conducted in Europe, about 55 percent of patients had relieved the pain within 15 minutes by using this device whereas 42 percent were able to prevent their migraine headache attacks. The SPG stimulation produces some of the disorders like one eye redness, rhinorrhea, eyelid edema, facial flushing or sweating, ear fullness, and ptosis.
This device is approved in Europe but further study has to be done in USA as it is not approved by FDA for the treatment of migraine and headaches in the USA.