title: An update to the Raymond-Roy Occlusion Classification of intracranial aneurysms treated with coil embolization.
abstract: BACKGROUND
  The Raymond-Roy Occlusion Classification (RROC) is the standard for evaluating coiled aneurysms (Class I: complete obliteration; Class II: residual neck; Class III: residual aneurysm), but not all Class III aneurysms behave the same over time.
  
  
  METHODS
  This is a retrospective review of 370 patients with 390 intracranial aneurysms treated with coil embolization. A Modified Raymond-Roy Classification (MRRC), in which Class IIIa designates contrast within the coil interstices and Class IIIb contrast along the aneurysm wall, was applied retrospectively.
  
  
  RESULTS
  Class IIIa aneurysms were more likely to improve to Class I or II than Class IIIb aneurysms (83.34% vs 14.89%, p<0.001) and were also more likely than Class II to improve to Class I (52.78% vs 16.90%, p<0.001). Class IIIb aneurysms were more likely to remain incompletely occluded than Class IIIa aneurysms (85.11% vs 16.67%, p<0.001). Class IIIb aneurysms were larger with wider necks while Class IIIa aneurysms had higher packing density. Class IIIb aneurysms had a higher retreatment rate (33.87% vs 6.54%, p<0.001) and a trend toward higher subsequent rupture rate (3.23% vs 0.00%, p=0.068).
  
  
  CONCLUSIONS
  We propose the MRRC to further differentiate Class III aneurysms into those likely to progress to complete occlusion and those likely to remain incompletely occluded or to worsen. The MRRC has the potential to expand the definition of adequate coil embolization, possibly decrease procedural risk, and help endovascular neurosurgeons predict which patients need closer angiographic follow-up. These findings need to be validated in a prospective study with independent blinded angiographic grading.
authors.affiliation: Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
authors.forename: Justin R
authors.initials: JR
authors.lastname: Mascitelli
authors.affiliation: Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
authors.forename: Henry
authors.initials: H
authors.lastname: Moyle
authors.affiliation: Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
authors.forename: Eric K
authors.initials: EK
authors.lastname: Oermann
authors.affiliation: Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
authors.forename: Maritsa F
authors.initials: MF
authors.lastname: Polykarpou
authors.affiliation: Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
authors.forename: Aanand A
authors.initials: AA
authors.lastname: Patel
authors.affiliation: Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
authors.forename: Amish H
authors.initials: AH
authors.lastname: Doshi
authors.affiliation: Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
authors.forename: Yakov
authors.initials: Y
authors.lastname: Gologorsky
authors.affiliation: Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
authors.forename: Joshua B
authors.initials: JB
authors.lastname: Bederson
authors.affiliation: Department of Neurosurgery, Icahn School of Medicine at Mount Sinai, New York, New York, USA.
authors.forename: Aman B
authors.initials: AB
authors.lastname: Patel
mesh_terms: D004621:Embolization, Therapeutic / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002532:Intracranial Aneurysm / Q000145:classification* / Q000175:diagnosis / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D016896:Treatment Outcome
keywords: Coil embolization; Intracranial aneurysm; Raymond-Roy Occlusion Classification