Rotational vertebral artery syndrome in moyamoya disease: A sign of unilateral vertebral artery stenosis

Abstract

Rotational vertebral artery syndrome (RVAS), also known as ow hunter’s syndrome (BHS), causes a transient hemodynamic schemia due to reversible compromises of the posterior circulation 1]. It is characterized by recurrent attacks of vertigo, nystagmus, nd ataxia induced by head rotation [1,2]. In RVAS, the hemodyamic ischemia is caused by mechanical steno-occlusion of the ominant vertebral artery (VA) against a fibrous band or bony rominence at the C1–C2 level by the head rotation under the conition that the blood supply through remained VA is insufficient 1–3]. The exact incidence of RVAS is unknown but thought to be rare. n literature reviews, we have found about 70 cases consistent with he diagnosis of RVAS, and it is suggested that the contralateral VA ends to be hypoplastic, stenotic or occluded [1,2]. However, RVAS s a sign of impending steno-occlusion of unilateral VA in moymoya disease has not yet been reported. We report a patient with oyamoya disease whose initially normal unilateral VA became tenotic during follow-up period and the other dominant VA was otentially compromised by head rotation that manifested as tranient vertigo and nystagmus.