title: Conventional endovascular treatment of small intracranial aneurysms is not associated with additional risks compared with treatment of larger aneurysms.
abstract: BACKGROUND
  Endovascular treatment of small intracranial aneurysms has historically been technically challenging and has been associated with high rates of complications and intraprocedural rupture. In this study, we compared complication and recurrence rates for treatment of small aneurysms (≤ 4 mm) versus large aneurysms in the context of the advent of improvements in endovascular techniques and technologies.
  
  
  METHODS
  A retrospective cohort study was performed to include all patients who underwent coiling of an intracranial aneurysm between 2005 and 2012. Small aneurysms were defined as any aneurysm 4.0 mm or smaller in all dimensions. The primary outcome was a composite outcome of the occurrence of an intraoperative rupture or a perioperative thromboembolic event. The secondary outcome of interest was aneurysm recurrence.
  
  
  RESULTS
  During the study period, 483 patients were treated using endovascular techniques; 85 (17.6%) of these patients had small aneurysms. In the small aneurysm group, there was only one (1.2%) intraoperative rupture, three (3.5%) perioperative thromboembolic events, and 11 (12.9%) incidents of aneurysm recurrence. Both the primary and secondary outcomes of interest were similar in patients presenting with small or large aneurysms. Small aneurysm size was not a risk factor for either the composite primary outcome or aneurysm recurrence in multivariate analysis.
  
  
  CONCLUSIONS
  Treatment of small intracranial aneurysms via conventional endovascular coiling techniques is not inferior to endovascular treatment of larger aneurysms based on our single institution experience. While technically challenging, such aneurysms may be treated safely and effectively with acceptable rates of complications and recurrence.
authors.affiliation: Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: William R
authors.initials: WR
authors.lastname: Stetler
authors.affiliation: Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Wilson
authors.affiliation: Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Wajd N
authors.initials: WN
authors.lastname: Al-Holou
authors.affiliation: Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Neeraj
authors.initials: N
authors.lastname: Chaudhary
authors.affiliation: Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Gemmete
authors.affiliation: Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: B Gregory
authors.initials: BG
authors.lastname: Thompson
authors.affiliation: Department of Neurosurgery, University of Michigan, Ann Arbor, Michigan, USA.
authors.forename: Aditya S
authors.initials: AS
authors.lastname: Pandey
mesh_terms: D015331:Cohort Studies; D057510:Endovascular Procedures / Q000009:adverse effects / Q000379:methods*; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome
keywords: Aneurysm; Coil; Complication; Stroke