[Arteriovenous fistulas. Apropos of 2 observations].

Two cases of mandibular angiodysplasia associated with hemorrhagic phenomena were treated surgically, by conservation resection in one patient and conservative surgery following embolization in the other. External carotid artery ligature is a useless and even risky procedure, whereas surgery should be preceded by tumoral embolization whenever possible. Prognosis, according to the classification proposed by Merland, depends upon whether active vascular malformations, mainly represented by arteriovenous fistulae, are present, or whether the lesions are inactive vascular malformations or with slowed circulation.