The Cause of Trigeminal Neuralgia
The cause of trigeminal neuralgia in most cases is one of the brain arteries that has changed position with aging and now is pulsating against the portion of the trigeminal nerve where the insulating myelin sheaths transition from central nervous system myelin to peripheral myelin. This is called the Obersteiner-Redlich zone. If the pulsation occurs here where the myelin is weak, cross-talk can occur between the fibers, and a short-circuit can be set up. This produces the severe, repetitive, lancinating pain that characterizes classical, typical trigeminal neuralgia. After many years, there can be a secondary constant background pain that occurs that may be constant or even burning in character.
Superior Cerebellar Artery Pulsating Against Trigeminal Nerve
Some patients with multiple sclerosis can get trigeminal neuralgia related to demyelination in the brainstem where the trigeminal nerve enters. These patients be helped with some slightly different treatments.
View under the operating microscope showing arteriual compression of the left trigeminal nerve at the brainstem