About Trigeminal Neuralgia

Causes | Treatment Options | Surgery | Secondary TN | Post Herpetic Neuropathy | Anesthesia Dolorosa

The trigeminal nerve branches into a portion of the scalp, the face, lips, eyes, nose, scalp, forehead, upper jaw and lower jaw, inside the mouth, part of the tongue, and every tooth in the mouth

Trigeminal Neuralgia (TN) also called Tic Doloureux is thought to be one of the most painful conditions known to medicine. It is characterized by sudden and severe stabbing, bursts of shock like or electrical pain usually on one side of the face. The pain can be triggered by simple activities like brushing teeth, eating and drinking or talking.

Pain attacks can come and go and can go into remission for long periods of time, from days to weeks to years. Atypical TN, a less common form of the condition, has an aching and burning component to it; sometimes both are experienced. In addition, TN can be a consequence of Multiple Sclerosis.

TN is a disorder of the fifth cranial nerve called the trigeminal nerve. The nerve is located in three branches on each side of the face: the eye, forehead and nose; the cheek and the jaw. Compression on a blood vessel can be a cause of TN. However there is more than one kind of TN and in reality the causes of TN are not fully understood.

TN is most usual after the age of 50 but people of all ages can suffer from it including infants and children. It is thought to be more common in women. In most people it's restricted to one branch of the nerve on one side of the face, but there are cases of bilateral TN where pain attacks can occur on both sides of the face in different branches of the nerve.

Many people with TN in the jaw mistakenly seek dental treatment as symptoms lead them to conclude it's a dental problem. In fact, what is needed is a referral to a neurologist for diagnosis and treatment.

Known as “the Suicide Disease”, TN is excruciatingly painful but is not fatal and, as a consequence of the acute pain episodes sufferers live with the fear of attack if the condition is not well managed.

The diagnosis is made on history and can often be confirmed by the effectiveness of the medication. Initial treatment is with anti convulsant drugs such as Tegretol, Neurontin or Lyrica. These medications reduce the excitation of the nerve. Opiates are generally not effective for TN.

If medication is ineffective or side effects are too severe there are neurosurgical procedures to either relieve pressure on the nerve or to create numbness instead of pain. About five out of every 100,000 people, or 1,500 people, are diagnosed with TN each year in Canada. In the US it is classified as a rare disease.

For a comprehensive description of TN go to:  http://www.umanitoba.ca/cranial_nerves/ccndhome.htm.

Causes

It is believed that TN is caused by irritation of the Trigeminal nerve by  a blood vessel sitting on its origin from the brain.  It can also result from the loss of the nerve’s protective covering in diseases like MS or from the pressure of a tumor on the nerve.

Treatment Options

Patients are usually treated first with drugs. The ones used are anti-seizure drugs and it is believed that these drugs alter the way the brain transmits pain signals. Drugs include:

	Carbamazepine (Tegretal)
	Oxcarbazepine (Trileptal)
	Gabapentin (Neurontin)
	Phenytoin (Dilantin)
	Baclofen

Links to Treatment of Trigeminal Neuralgia:

	Treatment Options: A talk by Vancouver neurosurgeon, Dr. Chris Honey
	Treatment of Trigeminal Neuralgia from the Centre for Cranial Nerve Disorders in Winnipeg, MB
	Options for Treating Neuropathic Facial Pain and Trigeminal Neuralgia from The Facial Pain Association in the USA

Surgery

If the drugs are ineffective or if the side effects become bothersome, then surgery is an option.  Surgical options can be classified in one of two ways:  Nerve preserving or nerve damaging.

Nerve Preserving Surgery

The Microvascular Decompression or MVD involves opening the skull and exposing the nerve. The surgeon locates the blood vessels near the nerve and places Teflon padding between the nerve and blood vessel. The MVD has a success rate of 85-90%. After 15 - 20 years about half the patients will have the return of some pain.

This is major surgery and the risks include death (up to 1% in some reports), stroke, hearing loss, facial nerve weakness, meningitis, cerebral spinal fluid leaks, and seizures.

Patients must remain in the hospital for 3 to 5 days and recovery can take about 2 months.

Percutaneous Procedures

Percutaneous procedures are done through the skin. The surgeon slides a needle into the skull base so that the tip lies near the Trigeminal nerve’s ganglion.

Glycerol or alcohol - is placed on the nerve and left there to chemically damage the nerve.

Balloon compression - a small balloon at the end of the needle is inflated for a few minutes which damages the nerve mechanically.

Radiofrequency uses electricity to damage the nerve.

In all these percutaneous procedures there is an 85% early success rate but within 5 years about half of the patients will have pain return. These procedures can be repeated.

The risks include meningitis, some difficulty chewing, a cheek hematoma, double vision, loss of the corneal reflex, anesthesia dolorosa, a sudden rise or drop in blood pressure, cerebrospinal fluid leaks and meningitis. Only 5% of patients will experience any complication.

Stereotactic Radiosurgery

There are several machines used. All provide focused radiation to a small point near the nerve’s origin from the brainstem.The nerve is damaged using radiation.

	Gamma Knife – uses cobalt radiation and is the machine used in Winnipeg (soon to be in Toronto and Sherbrooke)
	Modified LINAC  – this is machine currently used in Calgary, Vancouver, Toronto, Ottawa, Halifax, Montreal
	Novalis – currently only Canadian site is Calgary.  With this machine the  size and shape of the beam can be adjusted to achieve an optimal homogeneous or modulated dose of radiation.

Secondary TN

The compression of the nerve is caused by a tumor or a vascular abnormality. It occurs in less than 2% of TN. The pain is slightly different with some associated sensory changes, numbness or weakness.

TN Secondary to Facial trauma

The pain may be more throbbing and burning than the electrical shock like pains of typical TN and associated with significant facial trauma or reconstructive surgery.

Post- herpetic Neuralgia

The pain follows an attack of shingles. People describe it as a crawling, prickling and burning sensation.

Anesthesia Dolorosa

A complication of the surgeries for TN. Patients experience a combination of numbness and burning pain. It is very difficult to treat.