title: Results of Endovascular Coil Embolization Treatment for Small (≤ 5 mm) Unruptured Intracranial Aneurysms.
abstract: OBJECTIVE
  Researchers and clinicians have been unable to fully elucidate the natural course of and proper treatment for unruptured intracranial aneurysms (UIAs) smaller than or equal to 5 mm, particularly with regard to whether close observation or surgery is more appropriate. In this retrospective study, we evaluated the safety and efficacy of endovascular coil embolization of small (≤ 5 mm) asymptomatic UIAs by analyzing outcomes and complications associated with the procedure.
  
  
  METHODS
  We analyzed data from 150 patients with small asymptomatic UIAs (≤ 5 mm) treated with coil embolization between January 2011 and December 2015. Three-dimensional angiography was used to measure aneurysm size. We evaluated procedure-related morbidity and mortality, immediate post-operative angiographic results, brain computed thomography follow-up results on post-operative day one, and clinical progress.
  
  
  RESULTS
  UIAs occurred primarily in the anterior circulation area (142 cases, 94.67%), though eight patients exhibited UIAs of the posterior circulation. Following coil embolization, aneurysms with complete occlusion were observed in 137 cases (91.3%). Partial occlusion occurred in five cases (3.33%), while the procedure had failed in eight cases (5.33%). Procedure-related morbidity and mortality were five cases (3.33%) and zero cases, respectively.
  
  
  CONCLUSIONS
  The endovascular treatment of small asymptomatic UIAs is associated with good short-term outcomes without permanent neurologic complications as well as low overall complication and morbidity rates. Thus, the procedure should be considered for patients with smaller asymptomatic UIAs.
authors.affiliation: Department of Neurosurgery, Presbyterian Medical Center, Jeonju, Korea.
authors.forename: Siwoo
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Neurosurgery, Presbyterian Medical Center, Jeonju, Korea.
authors.forename: Tae-Sik
authors.identifier: 0000-0002-7147-7805
authors.initials: TS
authors.lastname: Gong
authors.affiliation: Department of Neurosurgery, Presbyterian Medical Center, Jeonju, Korea.
authors.forename: Yong-Woo
authors.initials: YW
authors.lastname: Lee
authors.affiliation: Department of Neurosurgery, Presbyterian Medical Center, Jeonju, Korea.
authors.forename: Hyo-Joon
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Presbyterian Medical Center, Jeonju, Korea.
authors.forename: Chang-Young
authors.initials: CY
authors.lastname: Kweon
keywords: Embolization; Endovascular procedures; Intracranial aneurysm; Morbidity