The Surgical Treatment of Trigeminal Neuralgia and Hemifacial Spasm A guide for you and your family
TRIGEMINAL NEURALGIA
As you probably know, 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 has potential serious side effects necessitating occasional blood studies. Dilantin, Baclofen, and Neurontin have been used, but have not been very effective.
Most patients referred to us already have tried these medications without benefit or their doctors have decided the risks of continued use of these drugs are too great. If you desire further treatment with these medications arrangements should be made with your personal physician or with a neurologist.
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 (See Figure 1). In general these branches correspond to the upper, middle, and lower portions of the face.
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Figure 1. |
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. 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 slight chance the pain will recur. If the numbness wears off and the pain returns the procedure can be repeated.
Since 1970 I have performed more than 2,000 operations for trigeminal neuralgia.
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 (See Figure 2).
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Figure 2: In trigeminal neuralgia, a pad is placed between an artery and the trigeminal nerve. In hemifacial spasm, the pad is placed between the vessel and the facial nerve. |
Figure 3: This is the area where the hair is shaved for the vascular decompression operation. The red line shows the skin incision, and the dotted line shows where the bone is opened. |
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 (See Figure 3). 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 to life. At the time of this publication in 2001, there has been no loss of life in more than 700 operations I have performed. In addition, there is a small risk of facial numbness, facial weakness, double vision, infection, bleeding, alterations of hearing or imbalance, paralysis, or 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. Most patients spend one day in the intensive or intermediate care unit immediately after the operation and another three or four days in the hospital The patient should plan on taking approximately two weeks off work after leaving the hospital. A follow-up appointment is scheduled six to eight weeks after leaving the hospital.
The other procedure I 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. Numbness can be achieved by a variety of means. A Novocain and Xylocaine injection, such as might be done by your dentist, may numb the area to control the pain for a few hours. In an attempt to give longer relief, alcohol may be injected into the nerves. The numbness and relief with an alcohol injection may last from a few weeks to many months. It is uncommon for an alcohol injection to relieve the pain beyond 18 months, and in most patients the relief lasts less than a year. The reason an alcohol block is not permanent is that the nerve regenerates after this form of treatment. Another method of treating tic involves cutting the nerves outside the skull, but this usually gives only temporary relief. An operation to cut the nerves inside the skull gives more permanent relief, but the operation carries significant risks and is no more effective than the radiofrequency procedure in most patients.
The percutaneous radiofrequency lesion 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 (See Figure 4).
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Figure 4: Needle placed in deep part of trigeminal nerve. |
The area of the needle stick is numbed with Xylocaine. 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 30 to 60 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 often 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.
A few patients note pain around the ear because of chewing muscle weakness and looseness in the jaw joint, but this disappears when the muscle recovers. There have not been any cases of facial paralysis in our patients as there have been with some of the operations inside the skull.
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. This has occurred in two of the more than 1,000 patients treated with this technique at Shands Hospital. 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. Approximately 1 in 200 patients had double vision after the procedure, but this disappeared completely after a few months in each case.
I began performing this operation when I was on staff at the Mayo Clinic 30 years ago and have performed more than one thousand of these operations.
Patients are evaluated in the clinic the day before the procedure. The evaluation includes a general medial exam, consultation with an anesthesiologist, laboratory tests, a chest X-ray, and an EKG. 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.
Patients are asked to inform us of their progress one-month following the procedure. A follow-up appointment is scheduled, if needed, to review any concerns. However, since many of our patients come long distances we do not recommend a recheck if the long trip would be inconvenient. The pain may return if the numbness recedes or disappears with time, in which case the radiofrequency procedure can be repeated. We are most happy to see patients any time if they feel we can be of assistance or if there should be a recurrence of the pain.
The majority of patients find numbness a good trade for trigeminal pain. The pain usually is so severe and devastating to most patients they want an operation that offers permanent pain relief. Other patients, however, may want to test the effect of a temporary lesion that causes numbness that lasts from several months to several years.
Radiofrequency Lesion or Alcohol Block
The easiest way to create a temporary lesion in the second (middle) or third (lower) branch of the nerve is to use a radiofrequency technique in which the needle is positioned in the nerve outside of the skull. An alternate method is to inject alcohol into the nerve at these sites. The disadvantage of the alcohol injection is that it is difficult to repeat because scarring develops in the nerve which prevents the alcohol from getting into the nerve on subsequent injections. The numbness associated with an alcohol injection or a radiofrequency lesion in a superficial location outside the skull usually lasts from two to 12 months. If there is satisfactory pain relief with a temporary lesion and the numbness is not unpleasant a permanent type of radiofrequency lesion can be done when the pain recurs. If the numbness was especially unpleasant because of a tingling or burning feeling in the numb area, a vascular decompression procedure could be done when the pain recurs. Alcohol injections may be used to numb the forehead, but are less effective for the first branch of the nerve than for the second or third branches.
Supraorbital Neurectomy
Pain in the upper branch of the trigeminal nerve that involves the forehead may be relieved temporarily by an operation called a "supraorbital neurectomy". This operation involves making an incision in the eyebrow and cutting or crushing the nerves in the skin above the eyebrow. This relieves the pain for six to 18 months in most patients by causing numbness in the eyebrow and forehead.
A more recent type of procedure that destroys the trigeminal nerve is called a "glycerol injection". The procedure is performed by injecting glycerol into the region of the trigeminal nerve. Soon after the glycerol injection was introduced some magazine articles stated glycerol obtained its effect by a mechanism other than causing damage to the trigeminal nerve. However, it now has been clearly demonstrated in experimental studies that the glycerol injection relieves trigeminal pain by damaging the trigeminal nerve.
We have used glycerol injections in the past, but now use them infrequently because the return of pain following a glycerol injection has been earlier and more frequent than after a radiofrequency procedure. We also have found the size of the numb area cannot be controlled as well with a glycerol injection as with a radiofrequency lesion. Eye complications related to eye numbness, which may occur after the radiofrequency procedure, also have occurred with the glycerol injection.
The main disadvantage of the glycerol injection when compared to the radiofrequency procedure is the glycerol injection is less likely than the radiofrequency procedure to relieve the pain at the time of the procedure. If the glycerol injection does relieve the pain at the time of treatment the chance of recurrence of the pain is greater than with the radiofrequency lesion.
We have stopped recommending the glycerol injection for the reasons mentioned above, but would consider using it if a patient has tried it previously and wants to try it again, or if the radiofrequency procedure has been unsuccessful. The location where the needle is inserted for a glycerol injection is the same as for the radiofrequency lesion.
Hemifacial spasm is a condition similar to trigeminal neuralgia and is due to an abnormal discharge of another nerve called the "facial nerve". In trigeminal neuralgia the abnormal discharge is in a pain-bearing trigeminal nerve.
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Figure 5: The appearence of the face with hemifacial spasm |
In hemifacial spasm the abnormal discharge is in the facial nerve which supplies the muscles of the face and thus causes twitching or spasms of the muscles of the face and not pain. (Figure 5). No drug has proven effective in preventing or stopping hemifacial spasm. Muscle relaxants and the drugs used for trigeminal neuralgia commonly are given to patients with hemifacial spasm, however they rarely help. In the past, attempts were made to cut or crush the branches of the facial nerve. However, these destructive procedures were associated with facial paralysis and when the paralysis recovered the spasms returned. One form of creating damage to the facial nerve now in current use involves injecting a bacterial toxin into the nerve. This results in relief of the spasms by causing weakness of some muscles of the face. It often is necessary to repeat the injections after two to six months. The most effective treatment of hemifacial spasm is a vascular decompression procedure of the facial nerve. The procedure is similar to the vascular decompression procedure described in the section on the treatment of trigeminal neuralgia, however this procedure is directed to the facial nerve approximately one-half inch away from the trigeminal nerve. The site of the skin incision and skull opening are nearly the same for trigeminal neuralgia and hemifacial spasm, however in hemifacial spasm the facial nerve is exposed. The risks of this operation are the same as those described in the section on vascular decompression operations for trigeminal neuralgia. The operation relieves the spasm permanently in the great majority of patients, however, as with trigeminal neuralgia, the problem may persist or recur in a few patients in spite of this form of treatment. The vascular decompression operation is the most effective permanent treatment for hemifacial spasm. We do not want these problems to create a financial hardship for any patient and if any problem with payment should arise we will be glad to have you review that with our financial counselor. Most patients who have trigeminal neuralgia are over age 65. Medicare covers the majority of the expenses for these patients. |
FOR FURTHER INFORMATION
If you need more information please contact:
Albert L. Rhoton, Jr., MD
R.D. Keene Family Professor and Chairman Emeritus
Department of Neurological Surgery
College of Medicine
University of Florida
PO Box 100265
Gainesville, FL 32610-0265
(352) 392-4331 or E-mail rhoton@neurosurgery.ufl.edu
