title: Current perspectives on the unruptured cerebral aneurysms: origin, natural course, and management.
abstract: BACKGROUND
  Unruptured intracranial aneurysms are common, but their rupture can cause subarachnoid hemorrhage. When managing unruptured intracranial aneurysms, we must assess the natural course and management risks of individual aneurysms. In this paper, we summarize current knowledge based on the literature about the natural course of these aneurysms and management risks and present our management strategy.
  
  
  METHODS
  An extensive literature review was performed to find risk factors affecting the natural course and management outcomes of unruptured intracranial aneurysms.
  
  
  RESULTS
  Risk factors for rupture, strongly supported by the literature, were the size, specific location, and shape of the aneurysms. Management morbidity was significantly affected by aneurysm size and location and the patient' age.
  
  
  CONCLUSIONS
  Unruptured intracranial aneurysms have various clinical characteristics, such as size, shape, and location and the patient's clinical condition, upon which management strategy should be stratified. In Japan, with national efforts to improve surgical and management standards, a national cohort study and individual case series have shown that the management morbidity of unruptured intracranial aneurysms is low. To improve care and to perform safer interventions, we must continue to seek better and less-invasive management methods and techniques.
authors.affiliation: Department of Neurosurgery, Nippon Medical School.
authors.forename: Akio
authors.initials: A
authors.lastname: Morita
mesh_terms: D017542:Aneurysm, Ruptured / Q000209:etiology* / Q000473:pathology*; D018450:Disease Progression; D006801:Humans; D002532:Intracranial Aneurysm / Q000209:etiology* / Q000473:pathology*; D016896:Treatment Outcome