Treatment of Trigeminal Neuralgia, Glossopharyngeal Neuralgia, and Hemifacial Spasm

by Stephen B. Tatter, M.D., Ph.D.

• Introduction
• Trigeminal Neuralgia
• Glossopharyngeal Neuralgia
• Hemifacial Spasm
• Go to the MGH/Harvard Trigeminal Neuralgia/Hemifacial Spasm Homepage for links to more information about these disorders.

Intraoperative picture shows the trigeminal nerve with a vessel loop compressing it. Courtesy Dr Eskandar

Introduction

Recent evidence suggests that a number of neurologic syndromes characterized by paroxysms of motor (tics) or sensory (pain) activity may be caused by compression of the cranial nerves at the root entry or exit zone of the brain stem by blood vessels. This has lead to the dramatic demonstration that microsurgical microvascular decompression is a safe and effective treatment for these syndromes when they fail to respond to oral medications. While these syndromes are relatively rare outside of neurosurgical practice in specialized centers they can none-the-less be extremely disabling.

Trigeminal Neuralgia

Trigeminal neuralgia or tic doloureux is charterized by brief episodes of extremely intense facial pain often radiating down the jaw. These episodes can occur spontaneously or can be triggered by light touch, chewing, or changes in temperature (i.e. cold). The pain is so intense as to be completely disabling. In addition, weight loss is common because oral triggers prevent affected individuals from eating enough to maintain adequate nutrition. Trigeminal neuralgia is caused by irritation of the fifth cranial nerve (the trigeminal nerve) which is responsible for providing sensation to the face. This irritation is occassionally due to benign tumors or to multiple sclerosis either of which can usually be detected by a high quality MRI of the brain. In the majority of cases, however, imaging of the brain does not reveal a cause of the nerve irritation. In such cases a small vessel (usually an artery but occassionally a vein) is often found to be compressing the root entry zone of the trigeminal nerve at the brainstem.

Repositioning this vessel using microsurgery is an effective method of treating many people with this disorder. The majority of patients who have this procedure performed by a qualified neurosurgeon have no facial numbness and and are pain free, requiring no further medications. The first line of therapy is medical and consists of anticonvulsants such as Tegretol (carabamazepine) and related medications. Surgery is reserved for those who are unable to tolerate the side effects of these medications or for whom these medications are no longer effective.

Another category of surgical treatments are also effective in relieving trigeminal neuralgia. These involve making a partial lesion in the trigeminal nerve to produce facial numbness that is irreversible. The most commonly used version of this type of procedure, radiofrequency lesioning (RFL), was developed by Dr. William E. Sweet at Massachusetts General Hospital.

Glossopharyngeal Neuralgia

Glosspharyngeal neuralgia is closely related to trigeminal neuralgia but is thought to be caused by irritaion of the ninth cranial nerve (the glossopharngeal nerve) which is responsible for providing sensation to the back of the throat. The paroxysms of pain are, therefore, localized to this region. Treatment options are the same as those outlined for trigemenial neuralgia above.

Hemifacial Spasm

Hemifacial spasm or tic convulsif is characterized by facial muscle spasms or tics. These tics are usually not painful (although there is a sensory component to the facial nerve that can produce pain behind the ear, hearing changes are also noted by some patients) and initially effect only one side of the face. Hemifacial spasm is thought to be caused by irritation of the seventh cranial nerve (the facial nerve). A small vessel (usually an artery but occassionally a vein) is often found to be compressing the root entry zone of the facial nerve at the brainstem. This vessel is usually too small to be demonstrated by imaging studies such as magnetic resonance imaging (MRI), computed tomography (CAT scan), or even angiography (arteriography).

Repositioning this vessel using microsurgery is an effective method of treating many people with this disorder. The majority of patients who have this procedure performed by a qualified neurosurgeon have no further facial tics and require no further medications. Treatments include medical therapies as outlined for trigeminal neuralgia above, although anticonvulsants are more rarley effective for hemifacial spasm than for trigeminal or glossopharyngeal neuralgia. Another treatment option available at MGH is the injection of botulinum toxin into the face to produce a temporary partial paralysis. This procedure needs to be repeated approximately every six months.

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