2. Glycerol rhizolysis: this technique uses a chemical called glycerol to interrupt the transmission of pain through the nerve.
3. Balloon compression: a balloon is inserted alongside a particular nerve to compress it, resulting in injury. This injury prevents the pain transmission
4. Gamma knife therapy: Despite its name, Gamma knife therapy does not involve a knife. It is a device that uses focused beams of cobalt radiation into a small space. When used for neuralgia, this therapy uses the beams of radiation therapy to a nerve. The radiation will kill or“ lesion” the nerve thus, preventing pain transmission. This type of therapy was invented at the Karolinska Institute in Sweden in 1967.
Glossopharyngeal Neuralgia( GPN) is a far less common cranial neuralgia than transcranial neuralgia but can be confused due to similar characteristics. Like TN, GPN consists of brief episodes of recurrent sharp pains. However, the location of GPN pain is in the distribution of the branches of the glossopharyngeal and vagus nerves( cranial nerves IX and X) as opposed to the trigeminal nerve. Patients describe a severe, stabbing, lancinating( piercing) pain that lasts a fraction of a second up to 2 minutes. The pain may be located in the ear, base of the tongue, tonsils, or beneath the angle of the jaw. Triggers of GPN pain include yawning, talking, coughing, swallowing, or touching the outside of the ear.
Occasionally, GPN and TN may coexist. The incidence of GPN is very rare and estimated to be 0.2 to 0.7 per 100,000 patients. GPN is rarely seen in children, and is most commonly found in females. The majority of patients with GPN are over the age of 50.
Location of the glossopharyngeal nerve
The majority of cases of GPN are thought to be idiopathic( no known cause) as thorough imaging and physical examinations usually do not reveal any abnormalities. Secondary causes may be from compression of the glossopharyngeal nerve by blood vessels or tumors. The majority of secondary cases are believed due to an artery compressing the glossopharyngeal nerve as it exits the brain.
Considering the rarity of this disorder, a comprehensive evaluation should be undertaken. A high resolution MRI with thin views through the brainstem will help evaluate for tumors. Angiography of the spine will also identify any compression by a blood vessel.
First-line treatment is similar to that for TN, with medical management with anti-seizure drugs such as carbamazepine, oxcarbazepine, gabapentin, pregabalin, and phenytoin. Surgical options such as microvascular decompression have been successful with long-term pain-free outcomes in upwards of 80 % of patients with a low rate of complications such as dysphagia( difficulty swallowing) or hoarseness.
Nervus Intermedius Neuralgia( NIN) also known as geniculate neuralgia is an extremely rare condition affecting an estimated 0.03 per 100,000 people per year. It is usually seen in patients 50 years and older, and women appear to be affected more than men. The pain is a brief, sudden bout of pain felt deep inside the ear, lasting seconds to minutes. During the attack, the patient may complain of a bitter taste in their mouth. The nervus intermedius is a small branch of the facial nerve( cranial nerve VII) that supplies the inner ear, middle ear, mastoid cells, Eustachian tube, and part of the pinna of the ear. Contrast-enhanced imaging( MRA) should be utilized to identify dilation of a vessel or any abnormal vessels. Treatment regimens include carbamazepine and other anti-seizure drugs that are used to treat TN.
COMPARISON OF LOCATIONS OF Trigeminal Neuralgia( TN), Glossopharyngeal Neuralgia( GN), and ervus Intermedius Neural ia NIN
TN
GPN
NIN
Along the branches of cranial nerve V, V2 and V3: cheek bone and lower face
Along cranial nerve IX and X: inner ear, base of tongue, tonsils, or along angle of the jaw
Along the branch of cranial nerve VII, the nervus intermedius: deep inside the inner ear
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