Anatomical anomalies of the V3 segment of the vertebral artery in the Polish population.

PURPOSE: The aim of this study is to evaluate the incidence of the anatomical anomalies of the V3 segment of the vertebral artery in the Polish population. There is conflicting evidence on the incidence of these anomalies: Asian-based studies show high incidence of 10 %, whereas the North American study identifies these anomalies in less than 1 % of patients. METHODS: 1800 computed tomography angiographies (CTA) obtained at the Barlicki University Hospital in Lodz, Poland, were reviewed retrospectively. RESULTS: All the patients were Caucasians. There were 968 males and 832 females. The mean age of the patients was 58. CTAs were obtained for the following reasons: stroke 1312, trauma 25, vascular/aneurysm 216, and intracranial haemorrhage 247. Vertebral artery hypoplasia was present in 360 cases (20 %). Persistent intersegmental artery (type I anomaly) was not found in any study. Fenestration of the V3 vertebral artery (type II) was recognized in three angiograms (0.16 %). Vertebral artery ending up as posterior inferior cerebellar artery (type III anomaly) was seen in 11 patients (0.61 %). CONCLUSIONS: Very low incidence of V3 segment anomalies does not justify in our opinion routine vascular imaging in patients undergoing posterior cervical instrumented procedures.