BACKGROUND: Recognition of a dominant vertebral artery (VA) is important in cervical spine surgery planning. However, few reports have discussed the relationship between the VA and the transverse foramen (TF). This study investigated the morphological features of the VA and TF, and examined for any associated risk factors for VA injury. METHODS: We retrospectively reviewed 90 patients who underwent cervical contrast-enhanced computed tomography angiography (CTA). We evaluated VA diameter, TF dimensions, TF area, and the occupation ratio of the VA within the TF from C1 and C3-6 levels. RESULTS: TF mediolateral diameter, TF anteroposterior diameter, TF area, and VA occupation ratio were all larger in the VA dominant group. The shape of the TF was elongated vertically at C1 and horizontally at C3, with the degree of horizontal elongation decreasing from C4 to C6. The inter-TF distance was wide at C1 and narrow at C3. The mediolateral diameter, anteroposterior diameter, and area of the C5 TF tended to be larger on the dominant VA side. CONCLUSIONS: In patients with a left-right discrepancy in the TF on CTA, there is a tendency for a dominant VA to be associated with the larger TF.
Hayashi et al. (Mon,) studied this question.