The long-term outcome predictors of pure microvascular decompression for primary trigeminal neuralgia

The aim of this study is to provide credible and comparable evidence on the efficacy and safety of pure microvascular decompression (MVD) for primary trigeminal neuralgia (TN), and also to find out the possible prognostic factors of excellent long-term outcome after the surgery.

A prospective cohort study was conducted, involving the patients who met the diagnostic criteria of primary TN (both typical and atypical). The cohort patients underwent pure MVD, and then were followed up by independent neurologists. The possible prognostic factors were analyzed by the logistic method.

All 154 consecutive primary TN patients (98 typical, 56 atypical) underwent pure MVD from January 2001 to November 2005. The patients were followed up for median 5.6 years (10 lost in 5 years). Respective initial and 5-year's complete pain-free without medication (Barrow Neurological Institute pain score, I) rates were 84% and 72% for total primary TN, 87% and 80% for typical TN, and 79% and 54% for atypical TN. The Kaplan-Meier survival curves of 5 years demonstrated different long-term outcomes in different groups (typical TN vs. atypical TN). The typical symptoms (odds ratio [OR], 2.776), preoperative magnetic resonance indicating vessel compression (OR, 2.950), and obvious vessel compression found during operation (OR, 3.219) were proved to have a positive effect on long-term pain relief without medication.

This is a perspective cohort study of pure MVD, which confirms the long-term effectiveness and safety of the surgery for primary TN. Patients with typical symptoms, positive magnetic resonance findings, or obvious vessel compressions might have better long-term prognosis.