Use of histomorphometry in the assessment of fatal vertebral artery dissection

Abstract

Aim-To assess morphometrically the structural changes, which occur with ageing, along the length of the vertebral artery. Methods-A series of 36 vessels were removed at necropsy from subjects aged between 9 months and 86 years. Image analysis was used to measure the medial width, the circumference, the intimal: medial area ratio and the adventitial: medial area ratio along each artery. The artery from a case of fatal vertebral artery dissection, which occurred after a game of cricket and then chiropractic neck manipulation, was also examined in the same manner. The proteoglycan accumulation in the media was quantified using an eyepiece graticule. Results-The vertebral arteries were, on average, larger around the origin of the vessel from the subclavian artery, and the adventitia were relatively thicker at this point, and also after piercing the dura mater. The media were much thinner within the intracranial segment and pronounced intimal thickening occurred with increasing age. The dissected artery showed undoubtable pre-existent structural abnormalities, in the form of massive proteoglycan accumulation, which predisposes an artery to dissection. Conclusions-These data should help pathologists faced with the task of assessing the underlying structural integrity of the vessel wall in cases of vertebral artery injury.