The National Institute for Health and Clinical Excellence (NICE) has issued updated guidance to the NHS in England, Wales, Scotland and Northern Ireland on stereotactic radiosurgery for trigeminal neuralgia using the gamma knife. The Interventional Procedures Advisory Committee reconsidered the procedure based on the results of a systematic review commissioned by NICE.

It replaces previous guidance on stereotactic radiosurgery for trigeminal neuralgia (gamma knife) (Interventional Procedures Guidance no.11, September 2003).


This procedure is used to treat trigeminal neuralgia.

Trigeminal neuralgia is a condition characterised by sudden bursts (paroxysms) of facial pain. These may be triggered by touch; talking; eating, or brushing teeth. The pain occurs in the areas supplied by the trigeminal nerve: the cheeks, jaw, teeth, gums, lips and, less often, around the eye or forehead. Trigeminal neuralgia is rare; the mean annual incidence is 4 per 100 000 population.

Some people with mild symptoms recover without treatment. For most people paroxysmal bursts of severe pain continue indefinitely. 

The first line treatment for trigeminal neuralgia is medication. Surgery is considered for people who experience severe pain despite medication, or who have side effects from medication.

Gamma knife radiosurgery involves aiming a focused beam of radiation at the trigeminal nerve to destroy it at the point where it leaves the brain. It does not require skin incision or needle insertion. General anaesthesia is not required.

Other treatments for severe trigeminal neuralgia include: glycerol injection, which involves inserting a needle into the nerve under X ray guidance; radiofrequency radiosurgery, which involves applying short bursts of radiofrequency to the nerve through a needle; balloon microcompression, which involves inflating a balloon near the nerve. All of these are minimally invasive surgical procedures. Microvascular decompression is a more invasive procedure involving opening the skull.

Coding recommendations

X65.4 Delivery of a fraction of external beam radiotherapy NEC

Y91.8 Other specified external beam radiotherapy

Y11.7 Gamma wave destruction of organ NOC 

Z03.5 Trigeminal nerve (v)

In addition the ICD-10 code G50.0 Trigeminal neuralgia is assigned, or a combination of Dagger(†) and Asterisk(*) codes B02.2† Zoster with other nervous system involvement and G53.0* Postzoster neuralgia (B02.2†). In the ICD-10 4th Edition † and * codes must appear together, sequencing depends on which is the main condition treated or investigated during the consultant episode, if this is not clear the † code is assigned before the * code.