Objective.To summarize the experience of minimally invasive treatment in 520 patients with intracranial aneurysms on a retrospective study.Methods.The measures used in the treatment of 520 patients were reviewed in terms of timing of surgery,induced hypotensive anesthesia,brain protection combined with temporal occlusion of the feeding artery,external drainage of CSF,dynamic monitoring of intracranial pressure,blood flow velocity,serum osmolality and CT scanning,anti vasospasm therapy as well as selected interventional endovascular embolization of aneurysms.Results.Of the 520 patients,485 were treated with either direct clipping or endovascular embolization and 35 patients were treated non surgically.In 449 patients undergoing direct clipping and 36 undergoing endovascular embolization,intraoperative rupture of aneurysm occurred in 27 (6.0%) and 0%,respectively.Death occurred in 13 (2.6%),hemiplegia in 8 (1.6%),and vegetative state in 2 (0.4%).The operative mortality of direct clipping was 3.8% in 210 patients before 1990 and 1.8% in 275 patients after 1990 (36 patients undergoing endovascular embolization,the operative mortality was 0%).Conclusion.The outcome of patients with intracranial aneurysms can be markedly improved and the operative mortality can be lowered by minimally invasive treatment.