Evaluation of 40 hemifacial spasm patients with MR angiography of the brain and vertebral artery dominance in the etiology of hemifacial spasm

Abstract

Objectives: Hemifacial spasm is characterised by involuntary, rhythmic, tonic or clonic contractions originating from the facial nerve and occurring intermittently in unilateral facial muscles. The most commonly reported cause of hemifacial spasm is the compression of the facial nerve at its root exit/ entry zone by an ectatic or aberrant blood vessel, leading to local demyelination. In this study, we compared magnetic resonance angiography (MRA) findings from patients with hemifacial spasm and controls to determine whether vertebral artery dominance is part of the aetiology of this condition. Methods: This retrospective case-control study was conducted with data from 40 patients with hemifacial spasm who received botulinum toxin injections and for whom MRA findings were accessible, and 42 patients of similar age and sex who presented with symptoms of nonspecific headache in the outpatient neurology clinic. Magnetic resonance imaging and unenhanced time-of-flight MRA examinations from the study and control groups were evaluated. Results: A dominant vertebral artery was present in 52.2% of patients in the hemifacial spasm group and 33.3% of those in the control group, but this difference was not significant (p = 0.079). Conclusions: The lack of significant results supporting our hypothesis may be attributable to the small study population. Further studies with larger groups are warranted.