Introduction: Cerebral aneurysms are formed due to a weakness in the arterial wall, this cause a dilation and the subsequent risk of rupture, conditioning subarachnoid hemorrhage, being one of the causes of cerebrovascular disease with higher risk of morbidity or death. We presented the first brain revascularization microsurgery for the treatment of a complex cerebral aneurysm performed at the Dos de Mayo National Hospital.

Clinical case: Woman with a ruptured left paraclinoid giant aneurysm, from Piura, who underwent revascularization by means of an extra-intracranial first generation bypass, between superficial temporal artery and silvian branch of M2, using a mini-interfascial approach, sphenoid wing drilling, anterior extradural clinoidectomy, opening of the canal, distal dural ring and tandem clipping for reconstruction of the carotid artery, excluding the complex aneurysm, was the surgical strategy chosen.

Conclusion: Post-surgical evolution was favorable, with radiological evidence of complete tandem clipping and permeability of the internal carotid and bypass.