Demonstration of fluid channels in human dura and their relationship to age and intradural bleeding.

ABSTRACT

PURPOSE: This paper aims to make a systematic study of human dura to establish the presence of fluid transport channels and their relationship to age. METHODS: Samples of parasagittal dura from autopsy cases from mid-gestation to the ninth decade were examined by light microscopy. RESULTS: We have demonstrated the presence of unlined rounded spaces, uncommon in the fetus and neonate but increasingly evident after 30 weeks of postnatal life. We have shown that intradural bleeding is inversely correlated with the presence of these channels and with age. CONCLUSIONS: We suggest that dural maturation, involving the development of arachnoid granulations, may be related to dilatation of intradural fluid channels, allowing them to be identified histologically. The risk of reflux of blood into the dura appears to reduce with age.