Significance of neurovascular contact in classical trigeminal neuralgia

???????????????????????????????Neurovascular contact is considered a frequent cause of classical trigeminal neuralgia and microvascular decompression with transposition of a blood vessel is preferred over other surgical options in medically refractory patients with classical trigeminal neuralgia. However, the prevalence of neurovascular contact has not been investigated in a representative cohort of patients with classical trigeminal neuralgia based in a neurological setting and using high-quality neuroimaging and blinded evaluation. We aimed to investigate whether presence and degree of neurovascular contact are correlated to pain side in classical trigeminal neuralgia. Consecutive classical trigeminal neuralgia patients with unilateral symptoms were referred to 3.0 T magnetic resonance imaging and included in a cross-sectional study. Magnetic resonance imaging scans were evaluated blindly and graded according to presence and degree of neurovascular contact. Severe neurovascular contact was defined as displacement or atrophy of the trigeminal nerve. A total of 135 patients with classical trigeminal neuralgia were included. Average age of disease onset was 53.0 years (95% confidence interval mean 40.5-55.5) and current age was 60.1 years (95% % confidence interval mean 57.5-62.7). Eighty-two (61%, 95% confidence interval 52-69%) patients were female. Neurovascular contact was prevalent both on the symptomatic and asymptomatic side [89% versus 78%, P = 0.014, odds ratio = 2.4 (1.2-4.8), P = 0.017], while severe neurovascular contact was highly prevalent on the symptomatic compared to the asymptomatic side [53% versus 13%, P < 0.001, odds ratio = 11.6 (4.7-28.9), P < 0.001]. Severe neurovascular contact was caused by arteries in 98%. We conclude that neurovascular contact causing displacement or atrophy of the trigeminal nerve is highly associated with the symptomatic side in classical trigeminal neuralgia as opposed to neurovascular contact in general. Our findings demonstrate that severe neurovascular contact is involved in the aetiology of classical trigeminal neuralgia and that it is caused by arteries located in the root entry zone.

TAKE-HOME MESSAGE

  • Trigeminal neuralgia is an extremely painful condition associated with high morbidity. There is a causal association with neurovascular compression, but the extent and nature of this association is not fully known. This is particularly important given that vascular transposition can be very effective in refractory trigeminal neuralgia. This is the first prospective, consecutive, blinded 3.0T MRI study exploring the association between neurovascular contact and trigeminal neuralgia. Of 3869 patients seen at a major headache center, 135 were included in the study. Average onset age was 53 years. Any neurovascular contact was prevalent on both the symptomatic and asymptomatic side (89% vs 78%), but severe neurovascular contact, defined as contact associated with displacement or atrophy, was highly prevalent on the symptomatic side compared with the asymptomatic side (53% vs 13%; OR, 11.6) and was caused almost exclusively by arteries.
  • This is important information, as it highlights the difference between incidental and potentially pathogenic neurovascular contact, with direct implications for possible surgical management.

– Codrin Lungu, MD

Stine Maarbjerg, Frauke Wolfram, Aydin Gozalov, Jes Olesen, Lars Bendtsen. DOI: http://dx.doi.org/10.1093/brain/awu349 311-319 First published online: 25 December 2014
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