Significance of neurovascular contact in classical trigeminal neuralgia

Abstract

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.

Association between neurovascular contact and clinical characteristics in classical trigeminal neuralgia: A prospective clinical study using 3.0 Tesla MRI

“…The remaining 135 patients constitute the study population ( Figure 3). The clinical characteristics of the total patient population were described in previous papers (19,23), and the prevalence of NVC and its associated characteristics on the symptomatic and asymptomatic side was reported in a recently published paper (5). The evaluation of the NVC was uncertain on the symptomatic side in three cases and in five cases on the asymptomatic side.…”

“…This is of major importance to TN etiology and pathophysiology, and possibly also for selection of patients for microvascular decompression (MVD). However, approximately half of TN patients do not have a severe NVC on the symptomatic side (2)(3)(4)(5)(6). Furthermore, a simple NVC, i.e.…”

Quantitative sensory testing in classical trigeminal neuralgia—a blinded study in patients with and without concomitant persistent pain

“…Severe neurovascular contact was defined as either displacement or atrophy of the trigeminal nerve on the symptomatic side at the site of an offending blood vessel. 16 All TN patients were requested to complete a Pain DETECT Questionnaire right before QST to obtain pain intensity ratings for subgroup analysis. The Pain DETECT Questionnaire is a validated screening tool developed in cooperation with DFNS.…”

A Gain-of-Function Mutation in Nav1.6 in a Case of Trigeminal Neuralgia

“…Intraoperative microneurographic recordings in trigeminal nerve fibers after stimulation of the known trigger zone in a TN patient demonstrated afterdischarges that were absent when unaffected facial areas were stimulated (13), loss, demyelination and dysmyelination consistent with NVC of the trigeminal nerve (2). However, recent studies have suggested that only severe neurovascular contact, causing displacement or atrophy of the nerve, is associated with pain in classical TN (3,4), and some studies have questioned whether NVC is necessary and sufficient for TN, since pain can occur and recur in the absence of nerve compression (5,6). A recent study reported…”