Trigeminal Neuralgia Associated with a Variant of Primitive Trigeminal Artery: A Case Report.

Trigeminal neuralgia (TN) associated with a primitive trigeminal artery variant (PTAV) is a rare condition that causes severe facial pain. We report the case of an 81-year-old woman presenting with right facial pain. Brain magnetic resonance imaging revealed an aberrant artery originating from the cavernous portion of the right internal carotid artery (ICA), coursing laterally around the posterior clinoid process and running toward the anterior inferior cerebellar artery (AICA) territory, suggesting a PTAV. Although the pain subsided with carbamazepine, liver dysfunction developed; microvascular decompression was performed. Transposition of the PTAV in a lateral direction revealed a marked indentation at the root of the right trigeminal nerve. The PTAV was surgically transposed laterally and fixed to the pyramidal bone surface using a Teflon sling, whereas the proximal part was fixed downward to the brainstem. There was immediate facial pain relief, following surgery. We reviewed 27 cases of TN associated with PTA or PTAV reported in the literature, which showed that the average age of onset was similar to our case, at 56.5 years, with a male-to-female ratio of 1:2.85. The proportion of patients with PTAV with V2 region affected was highest (91.3%), with PTAV (AICA) being the most common aberrant blood vessel (40.7%). In cases of TN associated with PTA or PTAV, it is crucial to identify blood vessels that are compressing or contacting the nerve and transpose these arteries from the nerve. It is also critical to plan movement direction in order to prevent ischemia of perforators to the brainstem or internal auditory artery.