A dual concurrent mechanism explains trigeminal neuralgia in patients with multiple sclerosis.

Objective: In this clinical and neuroimaging study, we sought information on the possible role of neurovascular compression in multiple sclerosis (MS)-related trigeminal neuralgia (TN).

Methods: After screening 1,628 consecutive patients with MS, we enrolled 28 patients with definite unilateral MS-related TN. In these patients, we acquired dedicated 3T MRI scans, identified pontine demyelinating plaques, and, using highly specific diagnostic criteria, distinguished possible neurovascular compression.

Results: MRI scans in most patients showed a demyelinating plaque in the pontine trigeminal root entry zone on the affected side. The frequency of the neurovascular compression and its association with the pontine demyelinating plaque were higher on the affected than on the unaffected side (54% vs 0%; p = 0.0001).

Conclusions: Our observation that in many patients with MS-related TN a pontine demyelinating plaque and neurovascular compression coexist should prompt neurologists to seek possible neurovascular compression in patients with MS-related TN.