Multiple Vessel Compression of the Trigeminal Nerve Is Associated with Worse Outcomes in Trigeminal Neuralgia Following Microvascular Decompression

Introduction: Although the precise etiology and pathophysiology of trigeminal neuralgia (TN) are still incompletely understood, vascular compression of the trigeminal nerve is thought to be a common cause of TN and has been estimated to account for nearly 80% of cases. Whether the total number of compressive vessels impacts pre- and post-surgical pain outcomes in TN remains unclear.

Methods: We retrospectively reviewed all patients with TN who underwent MVDs at our institution from 2007-2020. The number and identity of compressive vessels on the trigeminal nerve were recorded. A Mann-Whitney U test was used to compare pre-operative and post-operative Barrow Neurological Institute (BNI) pain and numbness scores. A multivariate ordinal regression was used to assess the relationship between the number of offending arteries and veins with post-operative BNI pain and numbness intensity scores. A Cox proportional hazards model was used to assess factors significantly associated with increased risk for time to pain recurrence.

Results: We identified 496 patients with a single vessel and 381 patients with multiple vessels compressing the trigeminal nerve. Compared to patients with a single compressive vessel, patients with multiple sources of compression exhibited increased BNI pain scores pre-operatively (p=0.01). Additionally, pain recurrence was more frequent (p < 0.001) and occurred after a significantly shorter pain-free duration (p < 0.001) for the multiple compression group. Using multivariate ordinal regression, a greater number of arteries (p=0.03) and veins (p=0.03) were both significantly associated with higher pain scores at final follow-up. Furthermore, the number of arteries (p=0.01) and of veins (p=0.01) was significantly associated with a higher risk for pain recurrence.

Conclusion : TN patients with a single compressive vessel exhibited better pain outcomes following MVD. Patients with multiple compressive vessels exhibited higher pain scores pre-operatively and incurred a higher risk for pain recurrence, which occurred after a shorter pain-free interval compared to the single compression cohort.