Vertebral Artery Variation in Patients with Congenital Cervical Scoliosis: An Anatomical Study Based on Radiological Findings.

STUDY DESIGN Observational, anatomical, radiological study. OBJECTIVE To explore the incidence and type of vertebral artery variation in patients with congenital cervical scoliosis and approach their clinical importance during surgery. SUMMARY OF BACKGROUND DATA Congenital scoliosis of the cervical spine is usually sporadic and caused by a variety of bone structural anomalies. Most of the cases remain asymptomatic. Surgical intervention is the main management for patients with neurological compromise or with cosmetic demands. The operation involved more screw insertion and osteotomy than the regular degenerative cases. The incidence and pattern of vertebral artery variants in these patients have not been reported. METHODS Patients with congenital cervical scoliosis treated in our department were reviewed. We measured Cobb angle of cervical spine. We observed bilateral vertebral arteries and recorded variants. We measured their diameter in each segment through CT angiography. The bilateral diameter in each patient was then compared respectively. RESULTS There is a total of 44 patients enrolled. The incidence of vertebral artery variation was 41% (18 of 44). 50% (22 of 44) of patients had the dominant vertebral artery with no difference between concave side and convex side. Patients with a dominant vertebral artery had a larger Cobb angle than those who had not (30.25° vs. 23.24°, p < 0.05). The courses of vertebral artery were abnormal in 18 patients. 2 patients had unilateral variant in V1 segment. 12 patients had variants in V2 segment. 8 patients had variants in V3 segment. 3 patients had vertebral artery variants in multiple sites. CONCLUSIONS In patients with congenital cervical scoliosis, the dominance of vertebral artery is not related to the convex side or concave side, but patients with a dominance of vertebral artery have a larger Cobb angle. The incidence of variant in V2 and V3 segment is higher. A thorough evaluation of bilateral vertebral arteries is required before surgery. Extra cautious must be taken during surgery. LEVEL OF EVIDENCE 5.