title: [Very small intracranial aneurysms: Clip or coil].
abstract: BACKGROUND
  It is not unusual for very small aneurysms (≤3mm) to be responsible for subarachnoid haemorrhage. In addition, modern imaging has increased diagnosis of those that are asymptomatic. Because of their spatial configuration and thin and fragile walls, very small aneurysms can be a sizeable challenge for both open surgical and endovascular treatment. Based on recent literature data, the present manuscript reviews treatment indications and the choice of treatment strategy to occlude these particular aneurysms.
  
  
  METHODS
  Literature review concerning surgical and endovascular treatment of very small aneurysms (≤3mm). Arterial dissections and blister aneurysms were excluded.
  
  
  RESULTS
  We found no study that systematically and specifically assessed surgical treatment of very small aneurysms. Investigations of endovascular treatment are almost exclusively retrospective, usually evaluating a small number of patients, and are limited by selection bias. Despite often contradictory results, it appears that very small aneurysms carry a higher risk of rupture during endovascular procedures and higher ensuing mortality, as compared to larger aneurysms. The use of more flexible coils and additional endovascular tools appears to reduce this risk. There is no study comparing surgical to endovascular treatment.
  
  
  CONCLUSIONS
  Very small aneurysms carry higher treatment risks than larger aneurysms. A prospective randomised trial is justified for those very small aneurysms for which treatment is indicated.
authors.affiliation: Division of Neurosurgery, Department of Surgery, hôpital Notre-Dame, centre hospitalier de l'université de Montréal, 1560, Sherbrooke St. East, Montreal, Quebec, Canada H2L 4M1.
authors.forename: F
authors.initials: F
authors.lastname: Signorelli
authors.forename: F
authors.initials: F
authors.lastname: Scholtes
authors.forename: M W
authors.initials: MW
authors.lastname: Bojanowski
mesh_terms: D004621:Embolization, Therapeutic / Q000379:methods*; D057510:Endovascular Procedures / Q000379:methods; D006801:Humans; D002532:Intracranial Aneurysm / Q000150:complications / Q000628:therapy*; D012307:Risk Factors; D013345:Subarachnoid Hemorrhage / Q000209:etiology / Q000473:pathology / Q000628:therapy*; D016896:Treatment Outcome