Objectives: To assess whether contact of a vascular loop formed by the anterior inferior cerebellar artery (AICA) with the eighth cranial nerve correlated with unilateral auditory symptoms so as to produce a "vascular compression syndrome."
Study design: Prospective evaluation of patients with unilateral auditory symptoms using magnetic resonance imaging (MRI) scans to identify contact of a vascular loop with the eighth cranial nerve.
Methods: One hundred twelve patients with idiopathic unilateral auditory symptoms (42 women and 70 men, mean age of 51 years) were evaluated with MRI. Location of the vascular loop and contact with the eighth cranial nerve were assessed in each case. The asymptomatic contralateral ears of the patients were used as controls. A power analysis had determined the size of the sample to be studied.
Results: The arterial loop was found to be in contact with the eighth cranial nerve in 28 (25%) of the 112 symptomatic ears and in 24 (21.4%) of the asymptomatic (control) ears. The statistical analysis revealed that the difference was not statistically significant.
Conclusion: The results suggest that radiologic demonstration of contact between a vascular loop formed by the AICA and the eighth cranial nerve on MRI scans should be considered a normal anatomic finding and should not, on its own, be used to support the diagnosis of a "vascular compression syndrome."