Symptomatic and Asymptomatic Neurovascular Compression of the Trigeminal Nerve: Correlation with Magnetic Resonance Imaging Findings

Purpose: Neurovascular compression (NVC) is a major cause of classic unilateral trigeminal neuralgia. However, all cases of NVC may not develop symptoms typical of trigeminal neuralgia. In this study, we aimed to compare the various anatomical and radiological features of NVC in symptomatic and asymptomatic individuals on high-resolution, heavily T2-weighted driven equilibrium (T2-DRIVE) sequence. Materials and methods: This retrospective study included 31 patients in a symptomatic group (Group 1) and 31 patients in an asymptomatic control group (Group 2). T2-DRIVE imaging was evaluated in all patients for NVC of trigeminal nerve (CN V). Student’s t test and Chi-square test were used as appropriate. Results: In this study, NVC of cisternal segment of CN V was present on the symptomatic side in 100% of cases in Group 1, with 58.1% of cases on the opposite asymptomatic side. NVC was seen in Group 2 in 64.5% of cases. Symptomatic NVC was more common in the age group of 46-65 years with mean age of 50.2±12.9 years. The most common vessel associated with symptomatic NVC was SCA or its branches (67.7%), and venous loops were more associated with NVC in Group 2. Symptomatic NVC was associated with more proximal location, higher grades of NVC, smaller trigeminal-pontine angle and lesser nerve length as compared to Group 2. Conclusion: The presence of neurovascular compression by itself may not be enough to cause neuralgic symptoms. Higher grades of neurovascular compression at proximal points by an arterial loop in older individuals, with characteristic clinical features on the same side, are more associated with trigeminal neuralgia.