Perception of pain is a mechanism meant to protect the human body from potential damage. It is a short sensation that resolves promptly once the painful stimulus is removed. When pain persists and becomes chronic due to a chronic stimulation or malfunction on its pathway and processing, it becomes an unpleasant experience and may itself be damaging for an organism.

Facial pain occurs in various forms. Trigeminal neuralgia is considered one of the most severe types of pain in humans. Patients who seek medical care with this type of pain are usually completely devastated. The pain prevents them from eating or drinking and, as a result, they are malnourished and dehydrated. They often do not leave their homes because even a simple gust of wind may trigger an attack of acute pain.

To be able to treat the pain, we must specify its character and its cause. First of all, there are three basic groups of individual types of pain:

• typical (primary) trigeminal neuralgia

• atypical trigeminal neuralgia

• atypical (secondary) facial pain

The distinction is very important because misdiagnosing within the individual groups may cause damage to patients due to an inadequate surgical procedure.

The first type to talk about is atypical facial pain. It usually develops in patients between 30 and 40 years of age, more commonly in females but males may also suffer from it. This pain is permanent with invariable intensity and usually becomes worse with stress. Some professions with higher stress level are more predisposed to this type of pain, e.g. teachers.

This pain is very sharp and is caused by a pain modulation disorder. As a result, regular psychotherapy is required to remodulate and thus stop the perception of pain. Patients with atypical facial pain need psychotherapy with guidance of a specialist in psychosomatic pain. To convince patients to see psychotherapy specialist and start treatment is usually very difficult. In our society, many patients still believe that when they are asked to consult a psychologist, it implies that their doctor does not think the pain is real. To gain patients’ trust, it is important to speak with them about their problems in detail and inform them about all possible methods of therapy at the first session. Patients have to be explained the benefit of psychotherapy and understand the cause of their pain. Gaining patients’ trust is a critical factor as it makes the whole process of therapy much easier and more effective.

Another group of types of pain is represented by atypical trigeminal neuralgia. This pain has the same cause as trigeminal neuralgia but the symptoms are much more complex. As is clear from the description, these two types of pain have the same cause. The only difference is the symptomatology of atypical neuralgia which is affected by additional causes. The treatment of this disorder is thus identical with that of typical neuralgia.

Trigeminal neuralgia is characterized by a set of clearly set criterions which define the disease. An episode is described as a short stabbing sensation of pain which may attack repeatedly. This condition may develop into a chronic irritation which is called ‘status neuralgicus’. The stabbing sensations are followed by a pause and the pain stops after some time. If there is a permanent component of pain, we speak of atypical neuralgia. The pain usually changes with seasons. Pain attacks are often triggered at the break of warm seasons, i.e. in spring and autumn. Patients are usually pain-free in the meantime. Patients have a trigger zone, i.e. an area the irritation of which triggers the pain. The most frequent trigger zones are gums, lips and nostrils. A frequent trigger of this type of pain is a tooth extraction. The subsequent pain is falsely ascribed to problems with teeth and there have been cases of patients who had almost all of their teeth extracted because of the pain.

The first step in treating trigeminal neuralgia is a conservative approach. Such treatment is also a good differential diagnostic method. The drug of choice in these cases is carbamazepine (Biston, Timonil, Neurotop or Tegretol). It should be administered 2 to 3 times a day. The desired effect usually comes within a certain time after the beginning of administration and it is hasty to stop taking the medication after a few days without success. Adverse effects include drowsiness and overall tiredness of patients but that also depends on the administered doses. The administration of carbamazepine also serves as a good diagnostic test. If carbomazepine is effective in suppressing the pain, it is also very likely that a potential surgical procedure will have a good outcome.

When conservative therapy fails, surgical procedure (ranging from minimally invasive surgeries to more extensive procedures) may help. Some surgical procedures are meant to only suppress the pain and some are to treat the underlying cause of pain. To start speaking about indications for surgery, it is appropriate to explain the cause of these attacks of severe pain.

The pain arises from demyelination of the transition zone of the trigeminal nerve root. More specifically, demyelination means the loss of isolation of individual sensory fibers conducting the sensation of pain. Due to the loss of myelin, the sensation spreads across other fibers and increases the perception of pain. We can imagine the same principle in a computer which has sensors and cables that transmit packages of information. When the isolation of cables is damaged, you experience frequent short circuits and the computer itself gets faulty pieces of information. How does this happen? There are several causes. The most frequent source of pain is the pressure on an artery or vein in the transition zone in the posterior fossa. Other causes include the loss of myelin due to multiple sclerosis or viral diseases such as shingles.

If the pain is caused by an artery compressing the nerve, the logical means of suppressing the pain is to move the artery. That is not as simple as it may seem. The transition zone is very near the brainstem, the most important centre of vital functions. Thus the artery cannot be simply removed. It must be pushed further from the nerve and fixed in the new position. The artery is fixed with a loop and glued onto the adjacent bone with a biological glue. The loop holds the artery in place and, at the same time, protects it from any damage. The lentgh of such operation without complications is about 2 hours but it may last up to 4 hours. This procedure means a lot of stress for patients and is not suitable for older patients with other diseases. Although the age limit has been recently moved to 70 years of age, patients must be completely healthy. The first three days after operation are usually accompanied with a headache but it stops soon. This surgical procedure involves the risk of a partial loss of hearing on the side that has been operated on or facial palsy. On the other hand, the procedure is highly effective and relieves patients from pain in more than 80% of cases.

When a patient is not suitable for this type of procedure, there is another method available. It is called glycerol nerolysis and it merely blocks the conduction of pain. Glycerol neurolysis is a short and quite simple procedure based on the injection of glycerol into the trigeminal cistern. Glycerol primarily damages fibers with thicker meylin layer which are pain conducting fibers. During this procedure, a special long needle is guided through a small hole in the skull base into a basal cistern under the surveillance of X-ray. The procedure is suitable for older patients with other internal diseases who are not eligible for microvascular decompression. However, it is not as effective and the suppression of pain may last from several months up to years. There is also higher occurence of side effects whether it involves a tingling sensation in the face or the damage of cornea due to the loss of sensitivity in the first branch of the trigeminal nerve. That is why we recommend that all suitable patients undergo microvascular decompression.

Facial pain is very debilitating, however, when it is properly diagnosed, we can treat it and help patients. The key to success is to make a proper diagnosis and have a good relationship with patients, which makes it easier for us to make the right decisions and even treat patients whose treatment is based on psychotherapy.

In the near future, new neurostimulating techniques will make it possible for us to modulate pain directly at the cortex where pain is perceived. These techniques are no longer fictional and have become part of our therapeutic options. However, the selection of patients for this type of procedure has not been yet properly defined. Finally, it is important to note that in pain treatment we always apply conservative methods first before we start considering surgical treatment.