Trigeminal neuralgia due to venous neurovascular conflicts: outcome after microvascular decompression in a series of 55 consecutive patients.

Abstract

Implication of veins as neurovascular conflict (NVC) in the genesis of trigeminal neuralgia (TN) remains a matter of debate. Few reports dealing with venous NVC have been published. The objective of this study is to describe the outcome in a historical cohort of consecutive patients with classical TN due to venous compression. All patients with TN treated by microvascular decompression (MVD) from 2005 to 2013 were included if a marked venous compression was found at the surgery either alone or accompanied by an artery. Patients were evaluated for clinical presentation, operative findings and the long-term outcome. Outcome was considered favourable if patients were classed as BNI I or II (i.e. not requiring any medication). Kaplan-Meier analysis was used to determine probability of a favourable outcome at 10 years of follow-up. Out of the overall series of 313 patients having been treated by MVD and considered for the study, in 55 (17.5%) a vein was the main compressive vessel; in 26 (8.3%) it was the only compressive vessel. Probability of relief with no need for medication at 10 years was 70.6%. The patients with focal arachnoiditis had a poor long-term outcome, i.e. BNI III-V, in 85.7% compared with 20.8% without arachnoiditis (p = 0.0037 Fisher's exact test). No differences in outcome were found between patients presenting with purely venous compression and patients with mixed compression. Outcome was similarly good for patients with atypical neuralgia when compared to patients with typical clinical presentation. Venous NVC as a cause of TN is far from rare. MVD with complete liberation of the entire root in cases with clear-cut venous compression on imaging studies gives a good probability of long-term pain relief, thus encouraging to propose surgery for such patients.