title: Comparison of tertiary-center aneurysm location frequencies in 400 consecutive cases: Decreasing incidence of posterior communicating artery region aneurysms.
abstract: BACKGROUND
  The growing number of community hospitals with neurointerventional services over the past decade has changed the type and complexity of cerebral aneurysms referred to tertiary centers. The authors hypothesized that this would be reflected in changes in the location frequencies of aneurysms treated now compared to before the widespread institution of endovascular coiling.
  
  
  METHODS
  Using a prospectively collected aneurysm database, aneurysm location frequencies were retrospectively reviewed for the last 200 consecutively treated aneurysms (2009-2010) and 200 consecutive aneurysms treated starting from May 1999 to December 2000. International Subarachnoid Aneurysm Trial (ISAT) aneurysm location nomenclature was utilized. Two-tailed Student's t-tests were used to compare means and Fisher exact tests were used to compare proportions.
  
  
  RESULTS
  The location frequencies of all aneurysms (ruptured and unruptured) treated in the 2000 epoch as compared to the modern epoch showed significant changes for middle cerebral aneurysms (12.0% vs. 21.0%, P = 0.014), posterior communicating (21.0% vs. 13.0%, P = 0.0001), and para-ophthalmic aneurysms (10.0% vs. 25.5%, P = 0.0002). For unruptured/elective aneurysms, the change in posterior communicating aneurysms was even more pronounced (27.8% vs 3.6%, P = 0.0001). The rate of aneurysm coiling at the center rose from 26% to 37% (P = 0.02).
  
  
  CONCLUSIONS
  The significant reduction in the referrals to our tertiary center of less technically complex aneurysms (posterior communicating segment) and increased referrals of aneurysms not as amenable to coil embolization (middle cerebral artery) is likely attributable to the growth of neurointerventional services at community hospitals over the past 10 years.
authors.affiliation: Department of Neurosurgery, Johns Hopkins University School of Medicine, The Johns Hopkins Hospital, 600 N. Wolfe Street, Meyer 8-181, Baltimore, MD 21287, USA.
authors.forename: Alexander L
authors.initials: AL
authors.lastname: Coon
authors.forename: Alexandra R
authors.initials: AR
authors.lastname: Paul
authors.forename: Geoffrey P
authors.initials: GP
authors.lastname: Colby
authors.forename: Li-Mei
authors.initials: LM
authors.lastname: Lin
authors.forename: Gustavo
authors.initials: G
authors.lastname: Pradilla
authors.forename: Judy
authors.initials: J
authors.lastname: Huang
authors.forename: Rafael J
authors.initials: RJ
authors.lastname: Tamargo