Kinking, coiling, and diameters of vertebral artery first segment and their relationships to sex and side

Introduction: Recent information on tortuosity in the prevertebral (V1) segment of the vertebral artery is based on case reports rather than systematic data on its presence, types, diameters, and sex- or left-right differences. Aim: To estimate the frequencies of V1 tortuosity (kinking and coiling) and their relationship to sex and to the left or right side. Materials and methods: This computed tomography angiographic (CTA) study included 100 adults without cerebrovascular and other related disorders (55 men and 45 women; age range 33–75 years). The presence or absence of kinking and coiling of V1 segment, as well as their sides and sex of subjects were registered and diameters were measured at the end of V1 part. Results: We found tortuosity in 36% of subjects. Of these 36 cases, 19 were kinks and 17 coils. The kinks, with the exception of one on the right (in one man) were found either only unilateral on the left side (men 8; women 4) or bilateral (6 women only), while left-sided coiling was found both in men (9) and women (8). The finding of bilateral kinking only in women is a conspicuous sex difference. Conclusions: This first detailed CTA study of kinking and coiling of V1 showed absolute left sided predominance of V1 tortuosity.