[Wallenberg's syndrome due to vertebral artery dissection following minimal neck injury--report of two cases].

We described two cases of the lateral medullary syndrome (Wallenberg's syndrome) due to vertebral artery dissection following minimal neck injuries. The first case was a 45-year-old man, who hit his head and often rotated his head because of posterior neck discomfort. Two years after the injury, he suffered from sudden sharp neck pain, nausea, and vertigo, which was followed by left hand numbness and difficulty in walking due to the right lateral medullary syndrome. Angiography showed right vertebral artery dissection at the fourth segment. The second case, a 48-year-old man, suffered from neck pain immediately after he hyperextended his neck for painting a wall. Within several hours, he experienced left hand numbness and difficulty in walking due to the lateral medullary syndrome. Angiography showed a saccular aneurysm and dissection of the right vertebral artery at the fourth segment. In both cases, minor traumas were thought to be the causes of vertebral artery dissection. We surveyed previously reported 84 cases (men: 50, women: 34) of the vertebral artery dissection due to minor traumas. Seventy per cent of patients were in their third or fourth decade of life. The main causes of trauma preceding the dissection were neck manipulation especially chiropractics (52%). The third segment was most vulnerable. Delay in onset following neck trauma could be more than a week, but in most cases the delay was less than 24 hours. Cervical rotation and extension were thought to precipitate dissection.