Table 2: The three types of VA with comparison of affected and nonaffected sides.

Affected side
Type IType IIType III

Non-affected sideType I11 (9)7 (7)17 (5)
Type II6 (4)1 (1)0 (0)
Type III11 (10)2 (2)0 (0)
None1 (0)0 (0)1 (1)

Total29 (23)10 (10)18 (6)

The location of the dissection with reference to the distance from the union of the vertebral artery was evaluated, with a distance less than 1 cm counted as near.
( ): near the union.