Trigeminal Neuralgia

Trigeminal neuralgia is a condition comprising episodes of severe pain affecting the face, in the distribution of one or more branches of the trigeminal nerve. It is characterised by attacks of short, sharp stabbing pain, which may be superimposed on a more constant ache. These attacks can last for days or even weeks. When they settle the patient may remain pain free for many months. A sensory trigger such as chewing, teeth cleaning, speaking, or touching the face in a specific place can precipitate the attacks. It is more common in patients who have multiple sclerosis, but in most patients there are no obvious associations and the cause is unknown.

Treatment methods

Drug therapy

There is a wide range of drugs available for the treatment of trigeminal pain of which the best known, and probably most effective, is Carbamazepine. Some patients tend to require increasing doses over a period of time, often to the point where the high doses required lead to intolerable side effects. In these patients surgical treatment methods, including radiosurgery, may be considered.

Microvascular decompression (MVD)

Microvascular decompression involves manipulation of blood vessels in the region of the root of the nerve. It is performed under general anaesthetic. This has had consistently good results, approximately 90% of patients being pain free thereafter. However, it is a major operation which carries a small but real risk of serious complications, and it does have a recurrence rate.

Radiofrequency thermocoagulation

This technique is also performed under general anaesthetic and produces a permanent lesion of the nerve in the region of the ganglion behind the face. This usually results in pain relief in the appropriate area, and results are generally good. However complications, usually related to nerve damage, are relatively frequent.

Glycerol injection

Glycerol injections provide good pain relief with minimal sensory damage. Glycerol is injected directly into Meckel’s cave (where the branches of the nerve divide before going on to supply the face), and produces some local nerve damage. Pain control is generally good in the short term, but is often somewhat limited, and recurrence at a later stage is fairly common.

Gamma knife

Gamma knife is becoming increasingly popular for the treatment of this condition. A fairly large dose of radiation is delivered, but to a very small and highly focussed area of the nerve. The frequency of serious complications is extremely low, though a degree of tingling and numbness in the affected area can affect up to about 10% of people undergoing this treatment. Successfully treated patients usually respond after about 2 to 6 weeks, though some will experience pain relief sooner than this. Long-term outcome studies are still needed but favourable results are beginning to emerge. Treatment is probably not quite as effective as MVD, but this is offset by the fact that the complication rate is so low, and can be delivered on a day case basis rather than requiring general anaesthesia, major surgery, and prolonged hospitalisation. Current figures suggest that about 65% of patients treated by radiosurgery will experience good or excellent pain relief.