Objective: To examine surgical findings and results of microvascular decompression (MVD) for trigeminal neuralgia (TN), including patients with multiple sclerosis, to bring new insight about the role of microvascular compression in the pathogenesis of the disorder and the role of MVD in its treatment.
Methods: Between 1990 and 1998, 250 patients affected by trigeminal neuralgia underwent MVD in the Department of Neurosurgery of the "Istituto Nazionale Neurologico C Besta" in Milan. Limiting the review to the period 1991-6, to exclude the "learning period" (the first 50 cases) and patients with less than 1 year follow up, surgical findings and results were critically analysed in 148 consecutive cases, including 10 patients with multiple sclerosis.
Results: Vascular compression of the trigeminal nerve was found in all cases. The recurrence rate was 15.3% (follow up 1-7 years, mean 38 months). In five of 10 patients with multiple sclerosis an excellent result was achieved (follow up 12-39 months, mean 24 months). Patients with TN for more than 84 months did significantly worse than those with a shorter history (p<0.05). There was no mortality and most complications occurred in the learning period. Surgical complications were not related to age of the patients.
Conclusions: Aetiopathogenesis of trigeminal neuralgia remains a mystery. These findings suggest a common neuromodulatory role of microvascular compression in both patients with or without multiple sclerosis rather than a direct causal role. MVD was found to be a safe and effective procedure to relieve typical TN in patients of all ages. It should be proposed as first choice surgery to all patients affected by TN, even in selected cases with multiple sclerosis, to give them the opportunity of pain relief without sensory deficits.