Demyelinating Plaque Represents Cause of Trigeminal Neuralgia Secondary to MS

Demyelinating plaques play a primary role in the etiology of trigeminal neuralgia secondary to multiple sclerosis (TN-MS), whereas neurovascular contact plays no role, according to study results in Cephalalgia. Likewise, microvascular decompression may not be a suitable treatment strategy for patients with TN-MS.

In this study, a Danish team of researchers sought to determine whether neurovascular contact with morphological changes influences the etiology of TN-MS. They prospectively enrolled consecutive patients with TN-MS from the Danish Headache Center. The study investigators systematically collected clinical characteristics and neuroanatomical abnormalities in these patients. A blinded neuroradiologist performed magnetic resonance imaging (MRI) scans for examination of the trigeminal nerve.

A total of 63 patients were enrolled in the study, with 54 of these patients included in the MRI analysis. Overall, the mean age of patients at TN onset was 49.3 years (95% CI, 46.5–52.0). The mean age of the patient population at baseline was 56.5 years (95% CI, 53.6–59.5).

The study investigators observed a low prevalence of neurovascular contact with morphological changes on the symptomatic side (14%) and the asymptomatic side (9%), with no significant difference between the 2 sides (P =.157).

However, results indicated a significantly higher prevalence of demyelinating brainstem plaques along the trigeminal afferents on the symptomatic side compared with the asymptomatic side (58% vs 22%, respectively; P <.001). In addition, the presence of a demyelinating plaque was significantly associated with the symptomatic side (odds ratio, 10.6; 95% Cl, 2.5-44.8; P =.002).

In terms of study limitations, the study investigators noted that the MRI sequence did not include the medulla spinalis or medulla oblongata, nor did the study assess for plaques in higher brain structures.

While the study investigators concluded that microvascular decompression should be reserved for patients with classical TN, they suggest “the final decision of treatment strategy should rely on individual assessment, as this study cannot give a final conclusion on the possible benefits of microvascular decompression in patients with TN-MS.”

Reference

Noory N, Smilkov EA, Frederiksen JL, et al. Neurovascular contact plays no role in trigeminal neuralgia secondary to multiple sclerosis. Published online November 28, 2020. Cephalalgia. doi:10.1177/0333102420974356