Stereotactic radiosurgery for trigeminal neuralgia

The condition

2.1 Trigeminal neuralgia is a chronic pain condition that affects the trigeminal (fifth) cranial nerve, one of the most widely distributed nerves in the head. The pain occurs in areas supplied by the trigeminal nerve: the cheeks, jaw, teeth, gums, lips and around the eye or forehead. The typical form, type 1, causes sudden and severe facial pain, usually affecting 1 side of the face and lasting for a few seconds or minutes. It may be triggered by touch, talking, eating or brushing teeth. Atypical trigeminal neuralgia (type 2) is characterised by constant aching, burning, or stabbing pain of lower intensity than type 1. Some people have both types.

2.2 Trigeminal neuralgia can be idiopathic or may be caused by pressure on the trigeminal nerve from an artery or a vein (primary trigeminal neuralgia). It can also result from a medical condition such as a tumour, multiple sclerosis or injury (secondary trigeminal neuralgia).

Current treatments

2.3 Medication is the first-line treatment for trigeminal neuralgia. Other treatment options are considered for people who experience severe pain despite medication, or who have side effects from medication.

2.4 Percutaneous treatments include glycerol injection, radiofrequency lesioning (applying short bursts of radiofrequency to the nerve through a needle), and balloon microcompression (inflating a balloon near the nerve). The aim being to damage the trigeminal nerve and stop the transmission of pain signals. These procedures typically have high recurrence rates.

2.5 Microvascular decompression is a more invasive procedure involving opening the skull to relieve the pressure on the trigeminal nerve. This can provide longer lasting relief but carries a risk of potentially serious complications such as facial numbness, hearing loss, stroke and death.

The procedure

2.6 Stereotactic radiosurgery for trigeminal neuralgia uses precisely focused multiple beams aimed at the trigeminal nerve where it enters the brainstem, to deliver a high dose of ionising radiation in a single treatment session. It does not require open surgery, needle insertion or general anaesthesia. The aim is to damage the trigeminal nerve and stop the transmission of pain signals as with other percutaneous techniques.

2.7 There are different systems available for stereotactic radiosurgery and details of the techniques vary. In one system, a metal frame is attached to the patient's head with 4 pins inserted through the scalp under local anaesthetic. An imaging procedure (usually MRI) is used to accurately locate the target area for treatment. The patient lies with their head in a treatment machine for 20 minutes to 2 hours while the radiation is given. The frame and pins are removed before the patient goes home. In another system, a thermoplastic mask that covers the face is made for each patient. CT and MRI scans are used to locate the target. The radiosurgery is done using a robotic arm positioned over the patient, and takes about 40 to 50 minutes.

2.8 It can take a few weeks or months for the patient to notice any change after stereotactic radiosurgery.