We report a series of 11 patients who developed headaches during intra
cranial endovascular procedures performed for the treatment of arterio
venous malformations (10 cases) or aneurysms (1 case). Headache was pr
ecipitated either by balloon inflation (3 cases) or by embolization (8
cases), and had a very constant pattern. In all cases the pain starte
d suddenly, reaching maximum intensity at once. Headache was focal, un
ilateral, ipsilateral to the occluded artery, nonthrobbing and short-l
asting (usually less than 10 minutes). It was not associated with gast
rointestinal, autonomic, or aura-like symptoms. Headache localization
depended upon the catheterized artery, being constant for each of the
major vascular territories. Yet, in all patients pain was felt in the
cutaneous territory of the ophthalmic division of the trigeminal nerve
. The occurrence of headache was not associated with cortical deficit
nor cortical irritation (assessed both clinically and by the EEG) and
therefore seems to be directly related to the stimulation of the arter
ial wall. This type of pain can be used as a model of pure vascular he
adache. Its study can contribute not only to understand the pattern of
intracranial vascular innervation but also to understand or to refute
the vascular components of migraine.