Tethering of the vertebral artery in the congenital arcuate foramen of theatlas vertebra: a possible cause of vertebral artery dissection in children

Twelve children with vertebrobasilar artery stroke are reported (seven male s, five females; aged 6 months to 15 years). Patient 1 showed an arcuate fo ramen in the posterior arch of the atlas, an anatomical variant occurring i n 3 to 15% of the population. It was hypothesized that the presence of the arcuate foremen might cause tethering of the vertebral artery and lead to i ts dissection by repetitive trauma. Lateral plain films of the cervical spi ne in cases of posterior circulation stroke were taken. Eight of 11 patient s showed aberrant arcuate foramina, Of the remaining three patients, one ha d normal cervical spine X-rays, one had an absent right posterior arch of t he atlas following previous surgery for a cervical meningocele, and one pat ient had incomplete ossification of the vertebrae. Seven of the nine patien ts with arcuate foramina had vertebral angiograms, In all cases this showed the vertebral artery passing through the arcuate foramen before entering t he brain and an appearance consistent with arterial dissection and occlusio n at the same site below the foramen. Most documented cases of posterior ci rculation stroke in children follow trauma, which may be minimal or repetit ive, with thrombotic occlusion of the artery at C1-C2 level. The associatio n with an arcuate foremen and its possible causative role in the genesis of posterior circulation stroke in children has not been previously recognize d. There may be a causal association between the presence of an arcuate for amen, tethering of the vertebral artery in the foremen, and dissection from repetitive trauma with movement of the neck.