Trigeminal Neuralgia – “TN”

For some, it may mean brief episodes of facial pain that will come “out of the blue” and disappear just as quickly. For others, it will be relentless, lightening-like bolts of pain resulting in agony for the individual. Whatever your situation, you need to know that trigeminal neuralgia is a very treatable disorder and one in which effective management and in many cases, a long-term resolution is attainable. Although TN is not a fatal disease, it may be a chronic problem. Fortunately for the patient, effective medications and excellent neurosurgical procedures provide do-able and livable options that can provide answers.

What is it?
Trigeminal neuralgia, also known as tic douloureux, is an excruciating facial pain that tends to come and go in sudden shock-like attaches. It is a chronic disorder of the trigeminal nerve (5th cranial nerve) which is the largest of the body’s 12 pairs of cranial nerves. The trigeminal nerve has three branches which conduct sensation from the upper, middle, and lower portions of the face, and also the oral cavity, to the brain.

Upper - 1ST Branch-Ophthalmic - Eye, eyebrow, forehead and frontal portion of the scalp

Middle - 2nd Branch-Maxillary - Upper lip, upper teeth, upper gum, cheek, lower eyelid and side of the nose

Lower - 3rd Branch-Mandibular - Lower lip, lower teeth, lower gum and side of the tongue. Also covers a narrow area that extends from the lower jaw in front of the ear to the side of the head

The painful attacks of TN can involve one or more branches. Most commonly the middle branch or the lower branch either individually or in combination with each other are involved. Only about 4% of patients experience pain in the upper branch. In rare instances all three branches may be involved. The right side of the face is more frequently affected than the left. In a small percentage of patients, pain occurs on both sides of the face, but rarely at the same time. The area of the nerve branch involvement determines the type of symptoms the patient will describe to the physician. It is extremely important that the patient gives a clear description of the area where the pain is being felt and the character of the sensation-constant, jabbing, shock-like, burning, etc. as this will help to confirm the diagnosis and recommendations for treatment.

Since the largest percent of patient have involvement of the middle and lower branches many of the initial symptoms are felt in the teeth and gums. Many patients experience a dull, continuous aching and gum sensitivity to heat and cold prior to the onset of the more intense, classical symptoms of TN. This period, sometimes referred to as pre-trigeminal neuralgia, presents a considerable diagnostic challenge, especially for the dentist since this is, quite often, the first health professional to see the patient. While true dental abnormalities do produce pain, the pain of TN is not caused by dental problems. What may appear as a toothache may actually be an early symptom of TN. It is not unusual for a TN patient to see half a dozen or more dentists, oral surgeons, ear, nose, the throat, and TMJ specialists, etc. Many modes of treatment-root canals, extractions, oral surgeries, etc.-are pursued, to no avail, while the pain steadily worsens and more classic symptoms of TN develop.

How TN is Diagnosed
Classic TN has distinct symptoms which clearly separate it from other forms of facial pain:

• Pain in short, acute bursts rather than a dull, constant ache. Often described as electric shock-like in nature.
• Pain is usually triggered by light touch or sensitivity to vibrations-brushing one’s teeth, shaving, a light breeze, a soft kiss, talking, etc.
• The pain has a tendency to come and go with periods of intense, sometimes totally debilitating pain, followed by complete pain-free periods of remission lasting from weeks to months or possibly longer.
• Most patients experience pain during the day while they are up and about. Generally, they are pain-free while asleep unless triggered by the touch of bed linens or changes in position.

The patient history and description of symptoms are the physician’s major aids in confirming the diagnosis of TN. Most doctors, including the surgeons at Central Wyoming Neurosurgery, will recommend a head/brain MRI or CT scan along with other laboratory tests. These are conducted mainly to rule out other possible causes of the pain such as tumors, multiple sclerosis, etc. There is no specific test available to confirm the diagnosis of TN.

Cause of TN
There are several theories on the cause or causes of TN, but not one that is universally accepted by all medical professionals. The majority of specialists believe that the protective covering (myelin sheath) of the trigeminal nerve deteriorates allowing abnormal messages (pain) to be sent along the nerve. These changes in the covering of the nerve may be caused by pressure from blood vessels, tumors, multiple sclerosis (which causes a breakdown in the myelin sheath of the nerve) and injury to the nerve or just the ageing process, in general. Like static in a telephone line these abnormalities disrupt the normal signal of the nerve and cause pain. Some cases of facial pain are caused by the herpes virus following cases of shingles, but are more correctly identified as post-herpetic neuralgia rather than TN. This form of neuralgia is treated by other modes of treatment, usually with anti-viral medications and anti-depressant drugs that alter transmission and help decrease the pain.

Who is Affected?
An early study (1945-1984) indicates that TN affects 1 in 25,000 people and occurs slightly more frequently in women than in men. It is estimated that each year 15,000 new cases will be diagnosed. More data is needed to confirm the current incidence of this disorder in today’s population. Most patients are over the age of forty with more individuals being affected in their 50’s and 60’s. However, TN can occur at any age. Several cases of TN in children have also been confirmed. There is an estimated 5 percent incidence of family history with TN.

Medical Treatment of TN
There is a growing arsenal of ways to treat TN, including medications and surgical treatments. The first universally accepted treatment option is usually through medications. Surgical procedures are used for those patients who are unable to tolerate the medications, exhibit serious side effects, or if the medications do not control the problem. Medications are initially effective for many patients, but over a period of time may diminish and require a surgical procedure.

During all phases of medical treatment patients need to have good communication with their physician and nurse to monitor their medication and response. The patient needs to understand the need to maintain a therapeutic blood level of medication for effective relief of their symptoms. Taking the medications irregularly is not effective. After the patient is pain free for 4 to 6 weeks the medications are tapered gradually. Abrupt withdrawal of medications can cause serious side effects. Analgesics (i.e. aspirin, Tylenol, etc.) and narcotics are not effective in addressing the pain of TN as it is of lightning-like intensity and the attacks are of brief duration.

• Carbamazepine (Tegretol) - has been the main drug used to treat TN. It is also used to treat seizures. Initial relief is so readily achieved that many physicians consider its use as a means to confirm the diagnosis. The drug is introduced slowly and increased to a level where the patient is pain free or side effects occur.
• Phenytoin (Dilantin) - is another drug that is used to treat TN, especially if the patient has had adverse side effects to carbamazepine (Tegretol). Since Dilantin may also be administered intravenously it is sometimes used to stop an acute attack, such as in the emergency room. Dilantin is considered to be less effective in addressing TN, but it may be better tolerated by the elderly patient.
  
  These drugs, which are also used as anticonvulsants, generally are thought to work by blocking the firing mechanism of the nerve. The more common side effects are dizziness, drowsiness, forgetfulness, unsteadiness, and nausea. Serious side effect may occur although they are rare. They include anemia, liver toxicity, and kidney dysfunction. Patients on Tegretol and Dilantin should have periodic blood counts to monitor any blood abnormalities.
• Gabapentin (Neurontin) - is a more recent anticonvulsant. Since it is eliminated by the body rather than metabolized it is felt to be more easily tolerated and to cause less liver toxicity. Neurontin has also been found to be beneficial in the treatment of some atypical facial pain syndromes and other painful nerve problems. It has also been used in the treatment of TN, but no data showing its effectiveness has been published.

Baclofen (Lioresal) - is a muscle relaxant that may be used alone or in combination with other medications. It seems to help increase their effectiveness if additional medication is needed.

Other medications used in the treatment of TN may include clonazepam (Klonopin), sodium valporate (Depakote) and pimozide (Orap).

Surgical Treatment
While these medications provide effective management for many TN patients, medical therapy is often not a permanent solution for this problem. Fortunately for the TN patient there are several neurosurgical procedures that are available if medication no longer provides the desired results.

The dilemma for the TN patient considering surgery is how to resolve the selection of a surgical procedure since there are several modes of surgical intervention available. Procedures vary from nerve blocks/injections, percutaneous surgery (through the cheek), to open skull surgery and pinpoint radiation. Each procedure has certain advantages and disadvantages-ease of the procedure, effectiveness, long-term results, recurrences, complications, etc. There is no one medical or surgical treatment that is effective in all patients. The choice between a procedure done as a one-day or outpatient (e.g., radiofrequency coagulation or glycerol injection) or one requiring a several days hospital stay (microvascular decompression) depends on the patient’s preference, physical well-being, previous surgeries, presence of multiple sclerosis, and area of trigeminal nerve involvement (some procedures are particularly indicated when the upper/ophthalmic branch is involved).

• Radiofrequency Rhizotomy (RF) – Percutaneous Stereotactic Radiofrequency Rhizotomy (or Electrocoagulation). This outpatient procedure is done under local anesthesia and sedation. A needle is placed through the face through which an electrode is inserted to heat the nerve and destroy the pain fibers. This procedure is the percutaneous “needle” procedure, which has a very high success rate but produces obligatory face numbness from destroying part of the nerve.
• Glycerol Rhizotomy – Glycerol Injection or Installation – Using a surgical technique similar to the RF (above) the surgeon injects glycerol (an alcohol substance) into the cavity where the trigeminal ganglion lies. The nerve is bathed with the glycerol to damage the pain fibers. This “needle” procedure also destroys part of the nerve but because it consists of an injection, it is less precise and more unpredictable than other procedures.
• Balloon Compression – Percutaneous Trigeminal Ganglion Compression – Also a “through the cheek” procedure, the surgeon first inserts a catheter up to the trigeminal ganglion (the central part of the nerve from which the nerve impulses are transmitted) and then inflates a tiny balloon to compress the nerve and damage the pain fibers. This “needle” procedure destroys less of the trigeminal nerve than other percutaneous techniques but has a high chance the pain will recur after the procedure, requiring re-treatment, which is less successful.
  
• Stereotactic Radiosurgery –LINAC Radiosurgery – This procedure consists of highly focused beams from cobalt or LINAC (Linear Accelerator) radiation, and a lesion (an area of controlled damage) is created in the root of the trigeminal nerve. The nerve develops a region of radiation injury over a period of time to interrupt the pain transmission. This is considered an ablative procedure, similar to radiofrequency rhizotomy although the results have not been as good, with less pain relief and high recurrence rates. We reserve this treatment for those patients who have failed all other treatments, including MVD.
• Microvascular Decompression – (MVD) – The operation is performed under general anesthesia where a small opening is made in the back of the skull on the side with the pain. The trigeminal nerve is viewed with a microscope and compressing blood vessels are moved away from the nerve and the nerve is padded with a soft sponge. The operative procedure takes about an hour and the stay in the hospital is about 2 days. The incision for the MVD procedure is small and is behind the ear on the side of the pain.
  

As discussed earlier, the most frequent cause of classic trigeminal neuralgia is a normal loop of a cerebral artery lying in contact with the trigeminal nerve. As the normal artery pulsates with the heartbeat, the artery rubs a small portion of the insulating sheath away from the trigeminal nerve and pain is transmitted to the nervous system at the slightest stimulation of the nerve. Fortunately this condition is extremely simple to treat with a high degree of success.

Dr. Thomas Kopitnik recommends a microvascular decompression that entails slightly moving the causative artery away from the nerve. Dr Kopitnik has performed over 200 of these decompressions for relief of TN. The operation is extremely safe and effective, with a 95% success rate of eliminating the pain. The hospital stay is usually only several days and the patients are weaned from their trigeminal medication shortly following the procedure. The ease and success of this procedure has been a godsend more innumerable patients suffering from this affliction.

Contact Central Wyoming Neurosurgery to request a consult with Dr. Thomas Kopitnik or Dr. Debra Steele if you suspect you suffer from Trigeminal Neuralgia.

More information is available by contacting the Trigeminal Neuralgia Association, 2801 SW Archer Road, Suite C, Gainesville, FL 32608 – Phone (352)376-9955 – Fax (352)376-8688. E-mail: tnanational@tna-support.org