[Angiographic signs of extra-dural hematomas of the posterior fossa (author's transl)].

Traumatic subacute and acute extra-dural hematomas of the posterior fossa are infrequent lesions which can be considered as exceptional From 1973 to 1977, we have collected 12 such cases. We performed 11 carotid angiographies and 7 vertebral angiographies in the series. Only in one case among 5 did clinical signs suggested a lesion of the posterior fossa. One of the best clinical elements to suggest such a lesion is the presence of a fracture line that crosses the lateral sinus, which necessitated a complete angiographic study. Arteriographic signs are function of the topography of the hematoma. The carotid angiography reveals only the supratentorial extension of the extra-dural collection of the blood clot. The most frequent sign is a filling defect of the affected sinus. The classic sign of detachment of the torcular is seen only in about 25% of cases. Vertebral angiography shows the existence of an expanding posteroinferior mass of the posterior fossa. Axial views always permits to find the avascular zone which corresponds to the extra-dural collection of the blood clot. In addition, vertebral angiography permits a good study of the sinusal drainage of the posterior fossa. In the purpose to find a supra-tentorial extension the prognosis of the extra-dural hematoma depends on its early discovery. The procedure of choice to make and to confirm such a diagnosis is vertebral angiography and it is not necessary to perform a carotid angiography in the cases where a supra-tentorial lesion does not seen associated.