Objective.-To prospectively describe the clinical characteristics of classical trigeminal neuralgia (TN) in a standardized manner.Background.-TN is a rare disease and most clinicians only see a few patients. There is a lack of prospective systematic studies of the clinical characteristics of TN. We hypothesized that contrary to current thinking, some TN patients suffer from sensory abnormalities at neurological examination.Methods.-Clinical characteristics such as demographics, pain characteristics, and comorbidities were systematically and prospectively collected from consecutive TN patients in a tertiary referral center in a cross-sectional study.Results.-A total of 158 patients were included. Average age of onset was 52.9 years. TN was more prevalent in women (95; 60%) than in men (63; 40%), P = .011, and more often located on the right (89; 56%) than on the left side (64; 41%), P = .043. It affected solely the second and/or third trigeminal branch in 109 (69%) while the first branch alone was affected in only 7 (4%). Notably, 78 (49%) had concomitant persistent pain in addition to paroxysmal stabbing pain. Autonomic symptoms were present in 48 (31%). Patients who had not undergone surgery for TN had sensory abnormalities in 35 (29%).Conclusions.-This, the first study in a series of papers focusing on the clinical, radiological, and etiological aspects of TN, revealed that the symptomatology of TN includes a high percentage of concomitant persistent pain, autonomic symptoms, and sensory abnormalities. These findings offer new insights to the prevailing clinical impression of the clinical characteristics in TN.

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.

Concomitant persistent pain is very prevalent in TN and is not a consequence of paroxysmal pain. Findings support that the 3rd International Classification of Headache Disorders beta division of TN with and without concomitant persistent pain is clinically and scientifically important.