What is trigeminal neuralgia?
People with trigeminal neuralgia experience sudden attacks of pain on one side of their face. The pain comes and goes intermittently. Trigeminal neuralgia affects the right side of the face more commonly than the left. It very rarely affects both sides of the face.
'Trigeminal' is the name of the particular nerve affected and 'neuralgia' is the medical term for nerve ('neur-') pain ('-algia').
The trigeminal nerve
The trigeminal nerve is the largest of the cranial nerves (nerves inside the head). There are two trigeminal nerves, one on the left side of the face and one on the right side. Each nerve has three branches (hence ‘tri-’). The first branch supplies feeling and sensation to the forehead, (opthalmic branch) the second supplies the cheek (maxillary branch), and the third supplies the jaw (mandibular branch). Doctors sometimes call these branches ‘divisions’.
The trigeminal nerves provide information about temperature, touch and pain from the whole front half of the head to the brain. They also control the muscles involved in chewing and equalising pressure in the ears.
Who gets trigeminal neuralgia?
Trigeminal neuralgia can affect people of any age but it is very rare in children. It is more common in older people and less common in younger adults. Women are affected more commonly than men.
How common is trigeminal neuralgia?
Trigeminal neuralgia is rare. It is estimated from a study of GP practices that trigeminal neuralgia affects around 0.1 per cent of the population in the UK.
What causes trigeminal neuralgia?
We do not know the exact cause for the majority of cases of trigeminal neuralgia. Different theories suggest that the underlying problem might lie within the brain, in the nerves inside the head, or in the nerve as it passes through the face.
Currently, the most popular theory is that people have a blood vessel pressing on the trigeminal nerve as it enters the brain in an area called the root entry zone. This is known as vascular compression. The pressure from the blood vessel damages the protective outer coating of the nerve (the myelin sheath). This results in the brain receiving signals from the nerve fibres that transmit pain.
Very rarely, trigeminal neuralgia can be caused by a tumour (usually benign) or a cyst pressing on the nerve.
People with multiple sclerosis can experience trigeminal neuralgia but it is extremely rare for this to be their first symptom. If you have trigeminal neuralgia, there is no reason to think you might be developing multiple sclerosis or any other serious condition.
What are the symptoms of trigeminal neuralgia?
People with trigeminal neuralgia might feel pain on the skin on their face or in their mouth and teeth. The pain can come and go suddenly and unpredictably. People often use words like stabbing, lacerating, electric shock-like and shooting to describe the pain. Attacks can range from fairly mild to excruciating.
Each burst of pain lasts only a few seconds or minutes but some people might experience several bursts in quick succession and this can last for hours. Other people might experience more than 20 shorter attacks a day. For some, the pain can persist at a lower level and feel like burning or aching for some time after the main attack of sharp pain.
The pain commonly affects the jaw and cheek but it might affect the whole side of the face. People often have 'trigger points' on their skin which bring on a sudden spasm of pain if touched. Various light touch activities can bring on the pain. For example, cleaning teeth, washing the face, shaving, eating, talking, laughing or smiling, the wind, a light breeze or air conditioning. Attacks of pain can also occur without any trigger. This is called spontaneous pain.
People might experience pain every day for weeks or months before it disappears completely for months or even years. As time passes, the attacks can become more frequent, last longer and be more intense. Currently, there is no way of predicting when the pain will come and go. As a result, between attacks, many people are very worried about when the pain might return.
Tests and investigations
Trigeminal neuralgia can be a difficult condition to diagnose because each person is affected differently and the pain can feel different for individuals. Many people visit their dentist when they first experience symptoms because the pain appears to come from a tooth or teeth. They might have extensive dental treatment before the diagnosis of trigeminal neuralgia is eventually made.
Because people’s nerves are working normally (even though they are sensitive) trigeminal neuralgia cannot be diagnosed by any specific tests. Doctors rely on accurate descriptions of the symptoms and careful, thorough examinations. It is very important to keep notes about the character of the pain: its frequency, the length of attacks, severity, location, factors that affect it, and any other features you notice.
It is important to rule out other possible causes of face and mouth pain. These include problems with the teeth, mouth, ears, skull and the glands around the mouth and the face, so these areas will be examined thoroughly. There are also a number of other conditions collectively known as trigeminal autonomic cephalagias which produce similar symptoms. During an attack, people with these conditions also experience physical symptoms on one side of their face such as redness of the eye and face, a runny nose and often tears.
After being assessed, you might have a brain scan to rule out the possibility that a tumour or lesion is putting pressure on the nerves. An MRI scan might show blood vessels touching or compressing the nerve. This is thought to be the cause of the majority of cases of trigeminal neuralgia. (You might be interested in reading our fact sheet on brain scans for further information.)
Anticonvulsants (or anti-epilepsy drugs) are the most common group of drugs used to treat trigeminal neuralgia. These drugs are also used to treat epilepsy. They work by reducing the activity of the nerves. Unfortunately, they do not cure trigeminal neuralgia but they can reduce the level of pain experienced. Anticonvulsant drugs need to be started at a low dose and very slowly increased to build up to the optimum dose for pain control.
The possible side effects of anticonvulsants include
- fatigue (severe tiredness) and
- difficulties concentrating.
In higher doses, the possible side effects include
- balance problems,
- memory problems and
- double vision.
Carbamazepine (brand name Tegretol) is the drug of first choice in the UK. It is effective for many people but, unfortunately, the possible side effects are often quite severe, especially in higher doses. It can also cause a rash in around 7 per cent of people who take it. (This is particularly likely to happen in Han Chinese and Thai people.) If this occurs, you should seek advice from your doctor and stop taking the drug.
Carbamazepine can interfere with the action of many other drugs so you should tell your doctors about any other medication you are taking. You will need regular blood tests when you first start taking carbamazepine, especially if you are taking a high dose. You might need to take an increased dose over time. Some people do not take the full dose because of the side effects. However, for 75 per cent of people with trigeminal neuralgia, carbamazepine is an effective treatment.
Oxcarbazepine is an alternative drug to carbamazepine. It is similar but has fewer possible side effects and does not interfere with other drugs as much. It is used in a similar way to carbamazepine. You will need to have regular blood tests with this drug, especially if you are taking a higher dose.
Phenytoin (brand name Epanutin), sodium valporate (brand name Epilim) and clonazepam (brand name Rivotril) are anticonvulsant drugs that are prescribed instead of carbamazepine, or possibly with carbamazepine. They might not be as effective but they can be useful for people who cannot take carbamazepine.
You might be prescribed drugs used to treat neuropathic pain (nerve pain). For example, gabapentin (brand name Neurontin) or pregabalin (brand name Lyrica). However, there is limited evidence that these particular drugs are effective in treating trigeminal neuralgia.
Baclofen is a muscle-relaxing drug often used for people with multiple sclerosis. For people with trigeminal neuralgia, it is usually combined with carbamazepine or phenytoin and can be effective in the early stages of the condition.
Lamotrigine can be effective for people with trigeminal neuralgia when it is prescribed with carbamazepine. It needs to be started at a very low dose and gradually increased to control side effects such as a rash.
The dosage of all these drugs can be increased over time if the pain becomes more severe. If your face pain disappears for over a month, the drugs should be slowly withdrawn and only restarted if the pain returns.
Many people find it helpful to keep a record of changes in the severity of their pain and the particular drugs and doses they are taking at the time. A good way to do this is to keep a pain diary with dates, a rating of the severity of your pain (for example, on a 1 to 10 scale), how the pain has affected your everyday activities (on a 1 to 10 scale), the drugs you are taking, and any side effects you are experiencing.
Drugs, initially, are the best form of treatment for trigeminal neuralgia if they are controlling the pain. However, if drugs fail to relieve the pain or cause unmanageable side effects, you might need to consider surgery.
It is important that you discuss the options with a neurosurgeon in the early stages of trigeminal neuralgia and that you have all your questions about surgery answered. Evidence is beginning to emerge that surgery carried out in the earlier stages of trigeminal neuralgia might result in improved outcomes.
Operations to treat face pain are mainly performed by a neurosurgeon - a specialist doctor who carries out surgery on the brain and spine (neurosurgery). Some of the procedures can be carried out by pain medicine doctors. There are different types of surgery used to treat trigeminal neuralgia.
Interrupting the nerve
Different surgical methods are used to interrupt or block activity in the trigeminal nerve. These methods can relieve the pain but, unfortunately, they nearly always leave an area of numbness or loss of feeling in the face because part of the nerve is destroyed.
The nerve can be interrupted at one of three sites:
1. The outside of the face
The small branches of the trigeminal nerve that pass inside the mouth and forehead might be cut (neurectomy), frozen (cryotherapy) or lasered. The surgeon can usually carry out these procedures under a local anaesthetic as a minor surgical treatment. People might be left with a small area of numbness in their face. Unfortunately, the pain is often only reduced for around ten months. Interrupting the nerve on the outside of the face is usually only recommended when other treatments are not possible.
2. The ganglion
The Gasserian ganglion (or trigeminal ganglion) is just inside the bottom of the skull. It is a group of nerve cell bodies on the trigeminal nerve the size and shape of a split broad bean. It contains the cells that supply the nerve fibres of the trigeminal nerve and is the point at which all the branches of the nerve meet.
To reach the ganglion, the surgeon passes a needle through the cheek into a small hole in the base of the skull. X-ray equipment is used to guide the needle. The surgeon then deactivates the ganglion by injecting it with glycerol or applying heat to it (thermocoagulation). Alternatively, the surgeon or specialist might compress the nerve with a tiny inflatable balloon positioned at the tip of the needle (balloon microcompression).
The procedures to interrupt the trigeminal nerve at the ganglion are usually carried out with the person under heavy sedation and partially awake so the surgeon can confirm that the needle has reached the correct place by checking their responses to stimulation. An overnight stay in hospital might be required for these procedures.
Interrupting the nerve at the ganglion usually allows the surgeon to treat larger areas of the face. Unfortunately, the majority of people having this surgery will be left with an area of numbness in their face. The numbness is usually less severe than the numbness following a neurectomy (see above). People often describe the feeling as similar to a dental injection wearing off.
Around 2 per cent of people will experience a condition called anaesthesia dolorosa after the surgery. Anaesthesia dolorosa is severe, dull, continuous pain in the numb area of the face. There is currently no cure for this condition. Around 10 per cent of people will experience some long-lasting or even permanent unpleasant sensations in their face after the surgery. The unpleasant sensations might be severe enough to affect the quality of people’s lives.
There are other possible risks with the techniques to interrupt the nerve at the ganglion and people should consider them carefully before deciding to go ahead with the surgery. As the needle passes into the skull, there might be complications that affect the brain. Less than 1 per cent of people are at risk of complications such as meningitis, brain abscesses, brain haemorrhages or heart attacks following the surgery. These are serious complications and can result in permanent mental and physical disabilities or death.
It is sometimes difficult for the surgeon to position the needle into the part of the nerve supplying the forehead. So, for people who experience trigeminal neuralgia mainly in their forehead, a large area of numbness might be created before any pain is relieved. An unfortunate result is that around 8 per cent of people in this situation experience a loss or reduction in their eye (corneal) reflex. This means that they cannot feel anything touching the eye so there is a risk of further problems if the eye becomes scratched or infected.
Around 10 per cent of people experience some difficulties with eating for a few months after the surgery, mainly after balloon microcompression.
Most people do not find the procedures to interrupt the nerve at the ganglion too uncomfortable but for some they can be an extremely unpleasant experience. Many people are prepared to have the procedures again if the pain returns.
3. The nerve trunk
The nerve trunk is the portion of the trigeminal nerve that emerges from the brain and extends to the ganglion. The procedure to interrupt the nerve at this point is called a partial sensory rhizotomy. It is less common than it used to be and is now carried out on relatively few people.
Under a general anaesthetic, an opening is made at the base of the skull just behind the ear. The surgeon identifies the trigeminal nerve using a microscope and cuts or crushes it to divide the nerve fibres supplying feeling to the parts of the face affected by pain. You will need a hospital stay of three to five days and around six weeks off work. People sometimes experience areas of numbness after this procedure.
Interrupting the nerve at the nerve trunk often provides a long-term cure for trigeminal neuralgia. The main disadvantage is the risk associated with surgery on such an important part of the brain. Even with the expert hands of a neurosurgeon taking the greatest possible care, the risks of this procedure are greater than the risks of alternative procedures. The exact risk differs for individuals depending on factors such as age and general health but overall there is a 0.5 per cent risk of death and a 1 per cent risk of serious physical disability.
There is also a risk that the nearby nerves coming from the brain stem will be damaged during the procedure. These include the nerves supplying hearing and balance and 4 per cent of people experience balance problems and deafness in one ear after the surgery. More rarely, people can experience weakness in the face (on the side of the operation), difficulties with swallowing, or double vision. Just less than 2 per cent of people experience damage to nearby nerves during the procedure. Some find that resulting problems can improve over the months following surgery.
Some people experience pain around the wound behind the ear or numbness in the ear. This usually improves but it might go on for several months. There is also a risk of anaesthesia dolorosa after the procedure.
Stereotactic radiosurgery (gamma knife)
Stereotactic radiosurgery (also known as gamma knife) is a newer treatment for trigeminal neuralgia. It is only available in a few specialised neurological centres in the UK. It involves interrupting the trigeminal nerve with high energy beams of radiation focused just behind the ganglion. It is not a surgical procedure and no incision (cut) is made. It is carried out with MRI scanner equipment. You will be fitted for a special metal frame to keep your head still. The treatment can take a few hours. You might need to stay overnight in hospital.
Early results of stereotactic radiosurgery suggest that people experience similar rates of pain relief to those achieved by other procedures that interrupt the nerve at the ganglion. The results for long-term pain relief are the same as those for other procedures. However, a disadvantage of stereotactic radiosurgery is that pain relief can be delayed for a few months and people might experience areas of numbness up to six months after the treatment. A very small minority of people might develop anaesthesia dolorosa.
Microvascular decompression of the nerve (MVD)
The surgical procedure of microvascular decompression (or neurovascular decompression) has been developed to provide treatment for trigeminal neuralgia without the risk of nerve damage, numbness or anaesthesia dolorosa.
With this treatment the surgeon makes an opening at the base of skull behind the ear (the same approach as a rhizotomy). The blood vessel pressing on the trigeminal nerve as it emerges from the brain stem is gently moved away and a variety of methods are then used to make sure the nerve is not compressed by a blood vessel. This is often done with fine strips of Teflon.
90-95 per cent of people experience immediate pain relief with this procedure and there is evidence to show that around 70 per cent of people are free of face pain ten years afterwards. Decompression of the nerve rarely results in areas of numbness or loss of feeling. There have been no reported cases of anaesthesia dolorosa.
The main disadvantage of this procedure is that it involves surgery on an important part of the brain and carries the same risks of serious complications as interrupting the nerve at the nerve trunk (rhizotomy). You will need to stay in hospital for three to five days. Most people recover fully within six weeks. The most common immediate complication is cerebrospinal fluid (the fluid surrounding the brain and spinal cord) leaking from the nose. This might require a further short operation. The other complications are the same as those for the partial sensory rhizotomy but the risk of numbness is extremely small.
As with several chronic pain conditions, attempts have been made to treat trigeminal neuralgia and other forms of face pain with neurostimulation. A variety of methods have been used to apply this technique. All involve placing an electrode on to the trigeminal nerve or ganglion.
Neurostimulation does not provide a cure for trigeminal neuralgia. Neurostimulation is not suitable for everyone and it is only used for a small minority of people with chronic face pain for whom it might provide some benefits. To receive neurostimulation, you will need to be referred to an expert in this treatment. You can discuss your options with your doctors. Currently, there is no evidence for its effectiveness in treating facial pain.
Who makes the decisions about my treatment?
If your face pain is controlled by drugs, this is likely to be the best form of treatment for you as an individual. However, if the pain is not controlled by drugs or you experience unmanageable side effects, you might need to give careful consideration to the surgical treatment options available. You should discuss the options with your medical and surgical team and be involved in any decisions about your treatment. Further support and information is available from patient support groups (see the Useful Contacts section).
Once you are clear about the potential benefits and risks of different surgical treatments, you will need to weigh them up and decide whether the risks are worth taking. This will differ for individuals. You should bear in mind the likely success of the different options, how long the benefits might last and what the specific risks might be. The Ottawa Personal Decision Guide might be a helpful resource.
Currently, the general view among specialists is that for healthy people microvascular decompression (decompression of the nerve) is likely to be the best option. For most people, this procedure provides lasting pain relief without numbness. For people with other health problems, those who cannot afford the time off work, and those who are unwilling to take the risks associated with microvascular decompression, the usual recommendation is to treat trigeminal neuralgia by interrupting the nerve at the ganglion. Relief from the pain will not last as long and there might be areas of numbness. However, procedures to interrupt the nerve at the ganglion can be repeated and different surgical treatments remain an option for the future. Microvascular surgery can also be repeated. Stereotactic radiosurgery (gamma knife) might be an option for people who cannot undergo surgery for medical reasons.
All of these factors need to be carefully considered by people deciding which treatment options might be right for them. No one should feel under pressure to have a particular treatment if they do not want it. You should bear in mind that not all the options will be available at the hospital where you receive your initial treatment. Also, not all the available treatments will be helpful for you, so your doctors might not offer them to you.