Trigeminal Neuralgia

Trigeminal neuralgia is a facial pain syndrome consisting of sharp, lancinating pain in the face. The pain is often described as shock-like stabs of pain. The pain is only on one side of the face and may be elicited by touching trigger points in the skin of gums. There is no associated numbness (unless there is co-existing multiple sclerosis). Often there may spontaneous remissions from pain lasting weeks to years. Interestingly, this pain usually responds to carbamazepine (Tegretol), an oral anticonvulsant medication.

Trigeminal neuralgia is usually caused by compression of the sensory (trigeminal) nerve within the skull by a small artery or vein at the point where the nerve joins the brain stem. Sometimes a small, benign tumor compressed the nerve, causing jolts of electrical shock–like pain to radiate into the face. A few percent of tic patients suffer from multiple sclerosis. In this case the inflammatory response affecting the brain also involves the trigeminal nerve, causing paroxysmal pain.

Tic douloureaux is unique among pain disorders because nearly all treatments work for a period of time. Over the years peripheral nerve avulsion, heating, cooling, compressing, decompressing, chemical ablation, and irradiation have all enjoyed varying degrees of success. Because of the effectiveness of carbamazepine (Tegretol), its use is usually the first level of treatment. Other anticonvulsants may be tried, but these are not usually as effective. When oral medication fails to control this dreadful pain, other surgical measures are quite effective. These procedures have challenged the imagination of neurosurgeons

Gamma Knife Radiosurgery

Gamma Knife radiosurgery can successfully treat tic pain. A single, non-invasive morning treatment has resulted in excellent pain relief in 58%; good pain relief in 36% and failed pain relief in 6%. Transient facial numbness is rare. Long term recurrence rates are unknown. This treatment is a suitable alternative to anticonvulsant therapy and compares favorably to other treatments.

A single 4 mm isocenter is focused on the left trigeminal nerve for Gamma Knife treatment.

Things you might need to know

Before any operation for epilepsy can be performed, there has to be a period of careful testing and evaluation.

These tests are done to make sure the surgery has a good chance of being successful and won't affect any of the important functions of the brain.

Most of the tests are used to pinpoint the area of the brain where seizures begin or to locate other areas, like speech and memory, that have to be avoided.

How many tests have to be done depends on the kind of operation that is being planned and how much information each test produces.

The following tests are most often used before a decision to operate is made:

Electroencephalography (EEG) : An electroencephalogram is a non-invasive, diagnostic test which records electrical activity on the surface of the brain, and can identify the location of the abnormally firing neurons. More Info

Magnetic Resonance Imaging (MRI) :Scans take pictures of the inside of the brain. MRI scans may show tumors, abnormal blood vessels, cysts, and areas of brain cell loss or other brain damage. More Info

Video EEG :In video-EEG, you are videotaped at the same time as your EEG is recorded. The recording is carried out for a long period of time, often several days. The doctor usually views the video and EEG images side by side on a split screen. In this way the doctor can see precisely how your behavior during seizures is related to the electrical activity in your brain. More Info

Neurological Exam :A neurological examination looks at how well your brain and the rest of your nervous system are functioning. Every time your doctor taps your knee with a hammer to see if your foot jumps, that's part of a neurological exam. More Info

Wada Test :The Wada test, also known as the Intracarotid Amobarbital Procedure (IAP), combines neuroimaging and neuropsychological testing methods to examine memory and language functions. It is used to evaluate patients being considered for epilepsy surgery, by examining the independent functions of the brain. More Info

Positron Emission Tomography (PET) :may be used in certain cases to help identify where seizures are taking place. PET measures how intensely different parts of the brain use up glucose, oxygen, or other substances. More Info

Single Photon Emission Computed Tomography (SPECT) :Individuals with epilepsy often have changes in blood flow to specific areas of the brain when a seizure begins. The SPECT measures blood flow between seizures and during seizures. The scans are then compared to identify the changes in blood flow in specific areas of the brain, thus identifying where seizures originate.

Decisions you need to take before head for a brain surgery

In trying to decide whether an adult or child will benefit from brain surgery, doctors want to know:

Is the problem really epilepsy?
Is it the kind of seizure that can be helped by an operation?
Have we tried hard enough to control the seizures with medicine, diet, or other treatment?
Might the condition get better without surgery?
Might it get worse without surgery?
Do the benefits outweigh the risks?
Can surgery be done safely in the affected area of the brain?

These are very individual questions with different answers for each person based on the medical history of the patient or his family; physical examinations; medical records; and a whole battery of pre-surgical tests.

All epilepsy surgery involves the brain. However, different types of operations may be done. In general they fall into two main groups:

Removal of the area of the brain that is producing the seizures.

Interruption of nerve pathways along which seizure impulses spread.

Lobectomy -- Seizures that begin in one or more areas of the brain are known as simple or complex partial seizures. The seizures can take on different forms, depending on where they originate in the brain. The brain is divided into areas called lobes. There are temporal lobes, frontal lobes, parietal lobes and occipital lobes. There are two of each lobe on either side of the head. An operation to remove all or part of these areas is called a lobectomy. This type of surgery may be performed when a person has seizures that start in the same lobe every time. It is sometimes possible to stop the seizures by removing the seizure-producing area if it can be safely done without damaging vital functions.
While there are risks in all surgical procedures, including the placement of depth electrodes and grids, most brain surgery for epilepsy appears to be relatively safe. The success rate for epilepsy surgeries depends on the type of operation performed and can usually be predicted after all the test results are available.

* For temporal lobectomies, 65 to 85% of patients will be seizure-free.

Complications occur in about 4 out of every 100 of these operations. Depending on the kind of surgery that's performed, possible complications include: partial losses of vision, motor ability, memory or speech. Infection or temporary swelling of the brain may also sometimes happen.

Hemispherectomy -- A lobectomy removes a fairly small area of the brain. However, when a child has Rasmussen’s encephalitis, a rare, progressive disease affecting one whole hemisphere of the brain, a hemispherectomy to remove all or almost all of one side of the brain may be performed. While it seems impossible that someone could function with only half a brain (the other side fills up with fluid), children manage to do so because the half that remains takes over many of the functions of the half that was removed. Weakness on the side opposite the operation will continue, however. Hemisperectomies may also be performed when children are born with conditions that cause excessive damage to one side of the brain, such as bleeding in the brain prior to birth.

Excellent results for this operation, which involve removal of one half or almost one half of the brain, are being reported by the small number of very specialized centers doing these operations. However, there are more risks with hemispherectomies than with other types of epilepsy surgery.

Children who have hemispherectomy operations will continue to have loss of function on the side of the body opposite the side where the brain was removed.

Corpus Callosotomy -- Another kind of surgery for epilepsy is called a corpus callosotomy (split brain surgery).

The corpus callosotomy operation does not take out brain tissue. Instead, it interrupts the spread of seizures by cutting the nerve fibers connecting one side of the brain to the other. This nerve bridge is called the corpus callosum.

The seizures which may respond to this type of surgery include uncontrolled generalized tonic clonic (grand mal) seizures, drop attacks, or massive jerking movements.

These seizures affect both sides of the brain at once and there is usually no one area which can be removed to stop them from happening.

Seizures are usually not stopped entirely by the operation. Some type of seizure activity on one side of the brain or the other is likely to continue, but the effects are generally less severe than the repeated drop attacks or convulsions.

The corpus callosotomy operation is often done in two steps. The first operation partially separates the two halves of the brain but leaves some connections in place.

If the generalized seizures stop, no further surgery is done. If they continue, the doctors may recommend a second step that completes the separation.

Among patients having a corpus callosotomy (split brain operation), risks of major and minor complications after surgery are around 20 per 100 operations. Generalized seizures may stop or happen less often than before the operation. Partial seizures (that is, changes in movement, feeling or emotion without loss of consciousness) will probably continue and may even get worse. Still, the uncontrolled drop attacks and generalized tonic clonic seizures that the operation is designed to treat have risks of their own. Decisions to operate take all these possibilities into account.

Multiple Subpial Transection -- Some seizures originate in or spread to parts of the brain that are responsible for functions such as movement or language. Removing these areas would lead to paralysis or loss of language function.

A surgical technique called multiple subpial transection (MST) may be performed in these situations. It involves making small incisions in the brain which interfere with the spread of seizure impulses.

This technique may be used alone or in addition to a lobectomy.

Vagus nerve stimulation (VNS) -- is a type of treatment in which short bursts of electrical energy are directed into the brain via the vagus nerve, a large nerve in the neck. The energy comes from a battery, about the size of a silver dollar, which is surgically implanted under the skin, usually on the chest. Leads are threaded under the skin and attached to the vagus nerve in the same procedure. The physician programs the device to deliver small electrical stimulation bursts every few minutes. This is a relatively new type of treatment. It may be tried when other treatment is not effective. Just how it works to prevent seizures is being studied.