Trigeminal neuralgia

Typical stimuli such as eating, brushing teeth, speaking or even without any recognizable cause can cause a stabbing pain that is perceived by those affected as extremely agonizing (“like being stabbed with a knife”). There are a number of therapies available to treat trigeminal neuralgia: pain relief with medication and various surgical procedures.

What is trigeminal neuralgia?

Although trigeminal neuralgia is not a common condition, it is extremely painful. The pain, which occurs in a flash, is almost always unilateral and can be felt in either the left or right side of the face. Frequently affected areas are the upper and lower jaw, the chin, the cheek and the lip region.

Around 13 people per 100,000 inhabitants are affected each year. In Switzerland, this means that around 1100 male and female patients are diagnosed with trigeminal neuralgia every year. They are usually over 50 years old, and women are slightly more frequently affected than men.

The trigeminal nerve is the largest of a total of twelve cranial nerves. Each of them is arranged in pairs on the left and right side of the head. Cranial nerves are nerves that do not originate in the spinal cord but emerge directly from the brain. As the Latin prefix tri (three) in the word trigeminal implies, the trigeminal nerve consists of three branches. Each of them forms fine branches. The first branch connects the brain to the forehead, the second runs from the nose, and the branches of the third branch originate in the lower jaw.

The trigeminal nerve primarily transmits sensory stimuli from the face to the brain, for example touch, temperature and odor sensations. It also plays a subordinate role in the movement of the masticatory muscles.

Doctors distinguish between three different forms of trigeminal neuralgia:

• Classic trigeminal neuralgia occurs when a blood vessel, usually an artery, presses on the nerve.
• Secondary trigeminal neuralgia occurs as a result of another disease, such as multiple sclerosis, a tumor or, for example, a stroke. These diseases can also lead to irritation of the trigeminal nerve.
• Idiopathic trigeminal neuralgia has a cause that cannot be precisely determined. But here, too, the pain is caused by an irritated nerve.

Diagnosis: How can trigeminal neuralgia be diagnosed?

In many cases, sufferers complain that they repeatedly experience severe pain that radiates to one side of the mouth and jaw. This often leads to trigeminal neuralgia initially being mistaken for a dental problem. Only a neurological examination and a correct diagnosis can provide the clarity required for successful treatment.

It is often the patients themselves who provide the decisive clues for the diagnosis: by describing exactly when, how long and how often their pain attacks occur. Nevertheless, additional examinations are often required to clarify whether trigeminal neuralgia is really present and not possibly another disease. One-sided, stabbing pain in the face – in the eye area – also occurs, for example, in so-called cluster headaches.

Various technical procedures help the neurologist to make an accurate diagnosis of trigeminal neuralgia. These imaging procedures include magnetic resonance imaging (MRI ) and computer tomography (CT).

Causes: How does trigeminal neuralgia develop?

The cause of typical trigeminal neuralgia is the contact of an actually healthy blood vessel with the trigeminal nerve at the point in the brain stem where the nerve enters the tissue. As a result, the usual excitation of the nerve fibers is disturbed. Stimuli that do not normally cause pain, for example harmless touches, are then perceived as painful in the face.

In rare cases, tumors or malformations of blood vessels can be the cause of trigeminal neuralgia. Another disease, multiple sclerosis (MS), can also be a possible trigger. In MS, the protective layers (the myelin) of the nerve fibers are broken down. In this case, not only older people are predominantly affected by trigeminal neuralgia and the pain can also occur on both sides.

Symptoms: How does trigeminal neuralgia manifest itself?

The pain attacks are often triggered by a light touch. For example, when shaving, chewing, applying make-up or through contact with water when showering. Even a gust of wind can be enough to cause a sharp, penetrating pain. In the vast majority of cases, it only affects one side of the face.

The pain attacks of trigeminal neuralgia can last anywhere from less than a second to two minutes. Sometimes the nerve pain only occurs sporadically, sometimes several times a day – in extreme cases up to a hundred times. The phases of such painful attacks can last for weeks or even months.

Between the individual attacks, there may be periods in which those affected have no symptoms. These pain-free periods can also last a very long time.

Treatment: How are trigeminal neuralgias treated?

There are two ways in which trigeminal neuralgia can be treated: with medication or by surgery. In most cases, doctors initially opt for drug therapy. It is not intended to treat the causes of the disease, but to alleviate the symptoms.

Often, however, the pain cannot be permanently reduced with the help of medication, or its side effects increase. In this case, your doctor will recommend an invasive (intervening in the body) treatment method. For example, an operation.

Neurosurgical intervention is also advisable if a diagnosis of secondary trigeminal neuralgia has been made, i.e. another disease that is responsible for the neuralgia. For example, a tumor that presses on the trigeminal nerve. In this case, the removal of the tumor should also cause the excruciating pain of trigeminal neuralgia to disappear.

Pain relief through medication

The pain attacks in trigeminal neuralgia occur suddenly and sometimes last only a few seconds or minutes. This is why many well-known painkillers do not help, because they take effect too slowly and therefore too late. Drugs commonly used for pain, even the strongest drugs such as opiates, are completely unsuitable for treatment. However, your doctor has other medications at his or her disposal. They are not used in acute cases, but are intended to prevent attacks of pain.

• Carbamazepine is an active substance that reduces the transmission of nerve signals.
• Oxcarbazepine is an active substance that can reduce the excitability of nerve cells.
• Gabapentin is an active substance that is intended to prevent the transmission of stimuli between two nerve cells.
• Pregabalin is an active substance that blocks the release of messenger substances (neurotransmitters) in the brain.
• Lamotrigine is an active ingredient that reduces the excitability of nerve cells and has an anticonvulsant effect.
• Baclofen is an active ingredient that relaxes the muscles and is mainly used in patients who suffer from multiple sclerosis as well as trigeminal neuralgia.
• Vixotrigine is a novel active substance that acts on the membrane of cells. Here it reacts to the activity of the so-called sodium channels. The active substance is still in the trial phase. The initial results of an international study in which the Center for Dental Medicine at the University of Zurich was involved are promising: they indicate that vixotrigine is well tolerated and significantly reduces trigeminal pain.

Good results are often achieved with medication, especially at the beginning of treatment. However, their effect often diminishes over time, or the burden of side effects such as fatigue or dizziness becomes too great. Then it is obvious to choose a surgical treatment method.

Pain relief through invasive treatment

There are various methods with which trigeminal neuralgia can be treated by surgery:

• Jannetta surgery, also known as microvascular decompression This method, named after its developer, involves making a small opening in the skull behind the ear. The hole allows direct access to the trigeminal nerve, which is under pressure from an adjacent artery. To relieve pressure on the nerve, a small plastic pad is inserted between it and the artery. Microvascular decompression is performed under general anesthesia.
• Treatment with heat, also known as thermocoagulation This is a so-called percutaneous operation (percutaneous = under the skin). The doctor pushes a probe under the skin of the face until certain branches of the trigeminal nerve are reached. A thin heat probe is used to obliterate or destroy the nerve fibers that cause pain. Thermocoagulation is usually performed under short anesthesia and on an outpatient basis.
• Treatment with pressure, also known as balloon compression In this percutaneous procedure, a needle is inserted through the cheek or out of the oral cavity towards the base of the skull. At the target site, a catheter with a small balloon creates pressure on fibers of the trigeminal nerve as soon as it is inflated. Once the fibers have been crushed, they are no longer able to transmit painful stimuli. Balloon compression can also be performed under short anesthesia and on an outpatient basis.
• Chemical treatment. This percutaneous operation for trigeminal neuralgia also involves first inserting a needle into the cheek area. When its tip has reached a specific nerve node in the skull, an injection of alcohol (glycerine) is given. The alcohol destroys the nerve fibers, blocking the transmission of pain signals. This procedure can also be performed on an outpatient basis and under short anesthesia.
• Radiotherapy. This treatment method is called stereotactic radiosurgery. Its tool is an irradiation device such as a so-called Cyber-Knife or Gamma-Knife – a neurosurgical “knife” that does not cut with a blade, but penetrates the body from the outside in the form of concentrated and highly precise radiation. In the case of trigeminal neuralgia, the rays are intended to damage the trigeminal nerve in a controlled manner – preferably in such a way that it no longer transmits pain, but retains the nerve connections that are important for the face.

Prognosis: How does trigeminal neuralgia progress?

If it is not treated, trigeminal neuralgia can have an extremely negative impact on quality of life. Not only because of the often very serious pain. Many sufferers change their everyday habits for fear of recurring attacks, with negative consequences for their health. For example, brushing teeth is neglected because it leads to attacks of pain. Some patients drink and eat too little because they are afraid that chewing or swallowing will trigger another pain attack.

These impairments are not only physically but also emotionally stressful. Quite a few people affected by trigeminal neuralgia become depressed and lose their courage to face life. In English-speaking countries, trigeminal neuralgia is therefore also referred to as “suicide disease”.

This makes it all the more important that this disease is diagnosed and treated at an early stage. With the right therapy, the pain attacks can become bearable or disappear completely – often even in the long term. For example, after a Jannetta operation, more than 80 percent of those treated report that they are pain-free immediately after the procedure. Ten years later, the number of symptom-free patients is still over 70 percent.

Other treatment methods also achieve good or very good results. Ask your doctor about this when it comes to deciding which therapy is best for you.