Potential Role of Turbulent Cerebrospinal Fluid Flow in Type 1 Trigeminal Neuralgia Without Neurovascular Compression: Insights From a Cerebrospinal Fluid Dynamics Study.

Abstract

Trigeminal neuralgia (TN) is a severe facial pain disorder typically caused by neurovascular compression (NVC) of the trigeminal nerve. However, a subset of patients with Type 1 TN presents without identifiable NVC on preoperative imaging. The pathophysiology in these cases remains unclear, and optimal surgical strategies are not well established. This study investigates the role of cerebrospinal fluid (CSF) flow dynamics in NVC-negative TN and explores its implications for surgical intervention. This single-center prospective study included 14 patients with Type 1 TN and no visible NVC who underwent arachnoid dissection around the trigeminal nerve and 25 patients with Type 1 TN and confirmed NVC who underwent standard microvascular decompression. Cardiac-gated phase-contrast MRI was performed preoperatively and postoperatively to evaluate CSF flow characteristics around the trigeminal nerve. Pain outcomes were assessed using the Barrow Neurological Institute (BNI) Pain Intensity Score. Pain relief was comparable between NVC-negative and NVC-positive groups (BNI score I/II, 78.6% vs 80.0%). In NVC-negative patients, the affected side demonstrated significantly higher mean CSF velocity, maximum velocity, and peak-to-peak difference than the unaffected side. These asymmetries were not seen in the NVC-positive group. Among 11 patients who underwent postoperative MRI (6 NVC-, 5 NVC+), the CSF flow differences resolved postoperatively. Aberrant CSF dynamics may contribute to the pathogenesis of Type 1 TN without NVC. Preoperative phase-contrast MRI may aid in identifying candidates for surgery. Arachnoid dissection targeting abnormal CSF flow may represent a viable treatment option for patients with TN lacking visible NVC.