neurosurg

Trigeminal neuralgia

The purpose of this document is to provide information about your forthcoming operation. Even though your surgeon may have explained to you what the operation entails most of us do not take in 100 % of what is said to us in an interview situation. This document is intended to help you to understand your condition and the proposed treatment. This is not however a document designed personally for you, and you should remember that there may be differences between your case and the information given here. If you are unsure about this please ask the admitting doctor when you come into hospital

What is Trigeminal Neuralgia?

You have been diagnosed as having Trigeminal Neuralgia. This is a condition which is characterised by very severe facial pain. The particular features of this condition are that the pain is almost always confined to one side of the face and it occurs out of the blue without any obvious cause and does not go away by itself in the long term.

Trigeminal Neuralgia is diagnosed mainly from the patients story. The pain typically occurs on one side of the face and may involve the upper, middle or lower thirds of the face, sometimes two thirds of the face and occasionally the whole of one side.

The character of the pain is that it is a very sharp pain, often described as feeling like ‘ red hot needles ‘ and the jabs of pain last for seconds or minutes and are of sudden onset. The pain may occur so suddenly that it can make the patient jump when it occurs.

Another feature of Trigeminal Neuralgia is that there is often a trigger spot on the face or in the mouth which if touched can start the pain off. The pain can also be provoked by touch, cold, washing the face, eating and talking. Unfortunately this can drive patients to despair and some patients lose weight and may even avoid social contact.

You do not need to have all of these features to have Trigeminal Neuralgia but usually most of them are present. Dull pain that spreads across the mid-line of the face and does not have typical provoking features is not Trigeminal neuralgia. If you have doubts about the type of pain that you are suffering, discuss this with your consultant.

What causes Trigeminal Neuralgia?

We do not know for certain what the underlying cause of this painful condition may be. There are however theories about the cause which seem to fit the facts and offer a chance of long-term treatment.

The nerve that supplies one half of the face and part of the scalp comes from the lower part of the brain at the back. It is thought that where the nerve enters the brain (the Root Entry Zone) a blood vessel lies in contact with the nerve and this ‘vascular compression’ causes the pain. This seems to be correct as the vast majority of patients that we operate upon do have this problem in this area. Unfortunately only 90% of patients do have a demonstrable vessel causing the pain at operation so we are not 100% certain that our theory is correct.

There are other causes of Trigeminal Neuralgia such as pressure from tumours or inflammatory conditions of the nervous system but most of these other causes can be excluded by doing a brain scan before planning treatment.

Treatment

Treatment of Trigeminal Neuralgia is divided up into medical and surgical treatment.

Medical Treatment

The mainstay of medical treatment is to give drugs that are normally used in the treatment of epilepsy. These particular drugs slow down nervous tissues ability to transmit the electrical impulses which allows nerves to function. The most effective of these is Tegretol (carbamazepine) which can be prescribed in doses up to 1200 milligrams / day. Other drugs such as Epanutin (phenytoin) and Epilim (sodium valproate) can also be used. Usually the pain is controlled by a small dose of Tegretol and other treatment is not needed as this drug is usually well tolerated and safe for long term use. The other drugs tend to be used if the patient does not tolerate the Tegretol for one reason or another. If the drugs don’t work there are surgical options that can be considered.

Surgery

A number of surgical procedures are available each with particular advantages and disadvantages. Your surgeon will be able to tell you which is the most suitable treatment in your individual case.

There are four basic ways to treat this condition:

1. A needle is placed under local or sometimes a general anaesthetic into the area where the nerve comes out of from the skull using x-ray control. A small amount of glycerin is then injected after which the patient has to keep still with the head held foreward for about 5-6 hours to allow the glycerin to do it’s job (not all surgeons feel that keeping the head still in this way is necessary ). It works by dehydrating the nerve and causing it mild damage and this reduces it’s ability to transmit pain. This is a good treatment but the effects last only from 6 to 24 months usually.

2. Instead of injecting anything into the nerve an electrical needle can be inserted into the nerve and used to cauterise the nerve partially. The needle placement is made more precise by being able to stimulate the nerve to produce a gentle tingle and when this is in the place where the patient has the pain that particular portion of the nerve can be heated up electrically. This is a good treatment but suffers from the disadvantage that it leads to a degree of permanent numbness of the face and also a kind of after pain can result (in 5-10%) which can be very difficult to treat. It does however give good long term relief of pain and only 15-20% of patients get the pain back in the long term.

3. The nerve can be cut. This is usually done by an open operation and usually results in complete facial numbness on that side of the face. This is only ever done as a last resort as the numbness of the eyeball that results can produce serious problems with vision in the long term.

4. The above treatments all work by damaging the nerve and the only treatment that we have which is non-destructive is an operation called ‘ micro-vascular decompression’.

Microvascular decompression is a relatively new operation that has been used now for about fifteen years. A small opening is made at the back of the skull and the edge of the brain is gently lifted aside. The Trigeminal nerve is identified and using a microscope is examined for contact with a blood vessel which is gently lifted away from the nerve and held away with a special tiny sponge ( see video). This effectively stops the pain in more than 97% of cases and leads to a permanent cure in approximately 90% of patients. This operation has the advantage that is very effective and does not damage the nerve and return of the pain is rare. Numbness following surgery is usually temporary however 15% of patients get some permanent loss of feeling in the face.

Your Hospital Stay

Shortly before admission to hospital it is likely that you will be seen in a pre-admission clinic where your general fitness for the anaesthetic is assessed. You may need a chest x-ray, ECG (a heart tracing) and some blood tests.

When you are admitted to hospital, surgery is usually carried out the following day. Most patients are given an injection or tablets before surgery to relax them (pre-med). The anaesthetist who puts you to sleep will visit the day before surgery to decide on this and on your general fitness for the anaesthetic.

On the day of surgery you will be taken to the anaesthetic room in the operating theatre and given an injection to make you sleep during the operation, after which you will awaken on the Neurosurgical Ward.

Possible Complications

Microvascular decompression is generally a safe procedure and can be carried out at almost any age. The oldest patient operated on in Middlesbrough with this operation was aged 89 and did extremely well!

You can expect to be in hospital for a minimum of five days, unless some complication arises. One of the risks of this operation is that when manipulating blood vessels in the base of the brain a stroke might occur. We have not had such a case in the last 10 years however.

Occasionally the fluid which bathes the brain can leak into the wound and require a small operation to repair the defect in the brains coverings. This is an uncommon event but should your wound leak any fluid or other matter following surgery it is important to inform your doctor.

Because other nerves are close to the Trigeminal nerve they can be affected by the surgery. This is very rare but there have been cases of weakness in the muscles of one side of the face temporarily, temporary double vision, temporary unsteadiness when walking and mild deafness on the side of the operation.

Return Home

On your return home you are unlikely to feel like doing your own cooking cleaning or shopping for at least a few weeks. It is important that you should have a friend or relative staying with you during that time to look after you during your convalescence. If this is impossible, discuss the matter with the ward sister in the pre-assessment clinic or when you are admitted to the ward.

Following the surgery you should not be in any severe pain. If you are, you should consult your GP or telephone the ward.

If the wound becomes red, painful, tender or swollen or discharges any matter it is important you should either telephone your GP or the ward.

The wound will either have staples to close the skin or a dissolvable stitch buried under the skin. Ask the ward staff to advise you about this before you go home, as the staples should be removed between five and seven days. You should avoid the wound getting wet during the first week after surgery. However, if the wound becomes wet when you wash your hair for example, you are unlikely to come to any harm and it can just be dabbed dry with a clean towel.

Most patients have returned to normal activities such as work and driving between six weeks and three months but this varies according to the patients age.

A normal sex life can be resumed within two or three weeks.

If the surgery is successful you can say goodbye to the anti-convulsant drugs as soon as you awaken after the operation.