Trigeminal neuralgia (TN) is an extremely painful condition that causes excruciating facial pain originating from the trigeminal nerve that can last from a few seconds to a few minutes. Typically patients experience sharp, shooting pain, usually on one side of the face. Pain can be brought on simply by touching your face, eating or brushing your teeth. As this condition progresses, episodes of pain often become more prolonged and painful. TN normally affects adults over the age of 50 years, but it can occur at any age. Women are affected more often than men. Sometimes no exact cause of TN can be found, but is usually caused by a blood vessel compressing the nerve or related to a disorder that damages the myelin sheath (the protective covering around the nerve). The myelin sheath carries sensory information such aspain, pressure and temperature from the face to the brain. When this is damaged or compressed, nerve signals can become erratic and hyperactive causing pain. Usually the compression is caused by the superior cerebellar artery, but it can also be caused by other arteries and veins surrounding the brainstem.
Symptoms of TN are varied and can include:
- Shooting pain that feels like an electric shock. These can last for seconds to minutes but can become constant
- Pain on one side of the face, affecting the eye, cheek and lower part of the face including jaw and gums
- Pain triggered by touch or sound
- Burning, aching pain
These attacks can be triggered by everyday activities such as talking, drinking and eating, brushing teeth, touching the face, smiling, exposure to hot or cold temperature and wind.
TN is mainly diagnosed by the description of the pain patients may be experiencing, including the type of pain, where it is located and what triggers it. Therefore TN is mostly diagnosed almost exclusively based on patient history and neurological examination. An MRI scan will also be used to visualise the trigeminal nerve and identify the presence of a compressive vessel. An MRI will also exclude other causes of TN including tumours or multiple sclerosis, which would require a different treatment.
TN is initially treated with medications such as anticonvulsants, which can help to control symptoms by blocking pain signals. These drugs do come with side effects such astiredness, upset stomach, dizziness, or blurred vision,and some patients will find these intolerable. Muscle relaxants, anti seizure or antidepressant drugs can also be used to help control symptoms, but are often not as effective in controlling TN pain. Patients will often need to take medication indefinitely, but some are eventually able to decrease their medications and live without pain.
Surgical treatment for TN is considered if pharmacological management has not worked or is no longer effective. There are a number of surgical options available including surgery to decompress the nerve or surgery to damage the nerve in order or reduce pain signals.
Microvascular Decompression (MVD) Surgery
The aim of this surgery is to relocate the blood vessel(s) coming into contact with the nerve. During the procedure, an incision is made behind the ear and in the skull. The trigeminal nerve is carefully exposed and a sponge-like pad is placed between the nerve and the blood vessel that is pressing on the nerve. If a vein is compressing the nerve, it may be removed entirely to relieve pressure on the trigeminal nerve. Postoperatively patients generally have an immediate resolution or reduction in their pain .
Radiofrequency ablation (uses high-frequency heat)
Radiation (high frequency heat)is focused directly at the root of the nerve in order to damage it. This damage results in a gradual reduction or elimination of pain. This is a non-invasive option
Trigeminal nerve block (injection)
A nerve block using local anaesthetic mixed with a steroid can rapidly relieve pain. This injection is done under x-ray guidance
A thin, flexible tube with a balloon on the end is inserted into the cheek and back of the mouth to the trigeminal nerve through a hollow needle. The balloon is then inflated the enough pressure to damage the nerve and block pain signals. This procedure is done under x-ray guidance.