About Trigeminal Neuralgia
Trigeminal neuralgia commonly is called "tic douloureux" or just "tic". When severe, it is the most excruciating pain known to man. This pain most frequently involves the lower lip and lower teeth or the upper lip and cheek, but it also may involve the nose and the area above the eye.
Routine pain medications often are ineffective in controlling this pain. The most effective drug for controlling this pain is Tegretol however; it often caused side effects such as somnolence, mental slowness, or imbalance. More serious side effects, such as blood and liver problems, may also occur. Dilantin, Baclofen, and Neurontin are also used for trigeminal neuralgia but are generally less effective. Almost all patients with trigeminal neuralgia initially obtain excellent relief from Tegretol, so we routinely recommend it. However, most patients find that, over time, larger and larger doses of medication are required and that it eventually becomes ineffective or caused intolerable side effects. At this point, fortunately, we have several excellent surgical alternatives.
In planning a surgical procedure for trigeminal neuralgia it is important to determine which branch of the trigeminal nerve is involved. The trigeminal nerve has three branches. In general these branches correspond to the upper, middle, and lower portions of the face.
The first (upper) branch includes the eye, eyebrow, and forehead. The second (middle) branch corresponds to the upper lip, upper teeth, upper gum, cheek, lower eyelid, and side of the nose. The third (lower) branch involves the lower lip, lower teeth, lower gum, and one side of the tongue. It also includes a narrow area that extends from the lower jaw in front of the ear to the side of the head.
Trigeminal neuralgia most commonly involves the middle (second) and lower (third) branches, but may involve the upper (first) branch alone, any two branches, or all three branches.
Treatment of Trigeminal Neuralgia
After identifying the affected branch the next decision is the selection of an operative procedure. We perform several types of surgical procedures for trigeminal neuralgia. The most common operations are the vascular decompression and percutaneous stereotactic radiofrequency lesion procedures.
The vascular decompression procedure is a major operation designed to minimize facial numbness as part of the treatment. The radiofrequency procedure is a more minor, needle-type procedure, designed to relieve pain by causing numbness in the face in the region of the branch or branches involved in the pain.
Another method of treating tic involves cutting the branches of the trigeminal nerve outside the skull, but this usually gives only temporary relief. An operation to cut the branches of the trigeminal nerve inside the skull gives permanent relief, but for most patients the operation carries significant risks and is no more effective than the radiofrequency procedure.
Injection therapy to offer temporary pain relief also is available. Novocaine or Xylocaine injections, such as those used in dentistry, can numb the painful area for a few hours. Alcohol and glycerol injections and other means of destroying part of the trigeminal nerve also may be considered.
With almost every type of injection and surgical procedure, including the radiofrequency lesion procedure, there is a small chance the pain will recur. If the numbness wears off and the pain returns the procedure can be repeated.
Vascular Decompression Procedure
The vascular decompression procedure is the operation recommended for a healthy person who does not want numbness of the face and is willing to accept a major operation entering the skull. It relieves trigeminal neuralgia by placing a small pad between the trigeminal nerve and the blood vessels next to the nerve.
The operation requires making an incision in the back of the head, creating a small hole in the skull, and lifting an edge of the brain to expose the trigeminal nerve which is located approximately two inches deep. The incision is made behind the ear on the side of the head where the patient feels pain.
The blood vessels that press on the nerve when the nerve leaves the brain are exposed and pushed away from the nerve. A small pad is inserted between the nerve and the vessels. This relieves the pain in most patients.
The operation requires a general anesthetic and involves a small risk of complications. These risks include facial numbness, facial weakness, hearing loss, double vision, infection, bleeding, stroke, hydrocephalus, CSF leak, and other neurological deficits.
Recurrent pain following the operation occurs in about 15 percent of patients. If the pain recurs another vascular decompression operation or a radiofrequency lesion procedure (described later) may be required.
The preoperative evaluation is done by the doctor and the Anesthesia Service in the clinic as an outpatient prior to the operation. The patient goes home or stays with their family in a hotel or motel in the area the night before the operation. The patient is admitted to the hospital on the day of surgery. The procedure typically takes about 45 minutes. Most patients spend two nights in the hospital. Intensive care is usually not necessary. The patient should plan on taking approximately two weeks off work after leaving the hospital. A follow-up appointment is scheduled four weeks after leaving the hospital.
Percutaneous Stereotactic Radiofrequency Lesion Procedure (RFL)
The other procedure we commonly perform to treat trigeminal neuralgia is called "percutaneous stereotactic radiofrequency destruction of the trigeminal nerve." The term "percutaneous" means the treatment is performed with a needle passed through the skin. The term "stereotactic" refers to the fact the needle is directed by X-ray control. The term "radiofrequency" refers to the radiofrequency heating current which is used to destroy the nerve.
Relief of the neuralgia by this method involves making the region of the pain permanently numb. The RFL procedure is performed in the operating room with the patient lying horizontally on his or her back. A needle is passed, under X-ray control, into the cheek on the side of the face where the patient feels pain and through a small, natural opening in the base of the skull into the trigeminal nerve.
The patient is put to sleep for a few minutes during the insertion of the needle and during the other painful parts of the operation. This is accomplished with a medication similar to Pentothal called Brevital which results in a very brief period of sleep.
After inserting the needle the patient is awakened and a small electric current is passed through the needle causing tingling in the face. When the needle is positioned so the tingling occurs in the area of the tic pain the patient is put to sleep again and a radiofrequency current is passed through the needle to destroy part of the nerve.
The patient is awakened a few minutes after completing the nerve lesion and is checked to determine if there is enough numbness in the face to give pain relief. The radiofrequency lesion procedure is repeated with the patient asleep until it has resulted in the desired numbness.
In most cases the X-ray portion of the procedure takes approximately 15 minutes. When the procedure is completed the patient goes to the recovery room for about two hours after which they can go home. They are usually able to eat the next meal. The numbness with this procedure usually is permanent. Should the numbness wear off, there is a chance of recurrent tic pain in which case the procedure can be repeated.
Several undesirable side effects may follow the procedure. The first is that the numbness may have an unpleasant or painful sensation. Often the numbness has an undesirable quality; similar to the way it feels after a Novocain injection. It is possible to stick a pin into the numbed area without the person feeling it, yet the patient may describe this sensation with words, such as it "tingles", "burns", "draws", "pulls", "crawls", or it is "woody" or "stiff, like cement".
Some patients find the numb area seems irritated or aches. One or two percent of the patients will find this sensation more disagreeable than their original tic pain. However, an overwhelming majority feel the numbness is far more preferable than the intense tic pain.
The second most common undesirable side effect is a weakness of the chewing muscles on the side of the head where the patient feels the pain. Many people describe the weakness as a change in their bite or as an inability to chew as hard on the side of the lesion. This weakness usually recovers six to eight months after the procedure.
The third undesirable side effect in an unwanted spread of the numbness to the adjacent branches of the nerve and to the eye. In some cases we actually are trying to numb the area in and surrounding the eye because the pain is situated there. Numbness of the eye itself is not harmful, but if foreign matter enters the eye the patient would not feel it. Inflammation, scarring of the cornea, and reduction or loss of vision could result. To prevent this we recommend each patient inspects the eye regularly with a mirror and to see an eye doctor if the eye becomes red or appears irritated, even though he or she may not experience pain.
A few cases of double vision have been noted after the procedure, but none of these have been permanent. Rarely, meningitis or other neurological problems may occur.
Patients are evaluated in the clinic the day before the procedure. Patients are instructed to go to the outpatient surgery desk on the morning of the operation and are taken to the operating room from there. After the procedure the patient remains in the recovery room for about two hours, after which the patient is discharged to their home. The patient returns to work a day or two following the procedure.
For additional information, visit the Trigeminal Neuralgia Association website.