Trigeminal neuralgia

Abstract

Trigeminal neuralgia is a facial pain syndrome that presents as a severe electrical, shooting pain lasting seconds to minutes in one or more distributions of the trigeminal nerve. The pain is almost always unilateral and triggered by touching the face or other innocuous stimulation of the trigeminal nerve. Most believe the cause to be a branch of the superior cerebellar artery compressing the nerve at the root entry zone. Medications such as carbamazepine and gabapentin are often initially effective, but this may wear off over time. The most effective surgical treatment is microvascular decompression, which involves mobilizing the artery off the nerve and/or interposing a piece of teflon felt between the two. Stereotactic radiosurgery using Gamma Knife or linac devices has been shown to be effective as well. Typical doses are from 75 to 90 Gy and treatment effects are felt within a few weeks. Initial response rates are high and vary from 70 to 90 %. Recurrences do occur more frequently over time, however, with only 34 and 22 % being free of recurrence at 5 and 7 years after treatment. Treatments at the original dose can be safely repeated although there is limited experience with three or more treatments. Side effects of SRS are uncommon and are dose related. Most often patients complain of facial numbness with dysesthetic pain being very rare. Despite the high doses, proper observance of the brain-stem dose delivered minimizes the risk of radiation necrosis.​