title: Preliminary observation on predicting the need for coil extraction  during microsurgery: the clip-coil ratio.
abstract: OBJECTIVE
  Coil extraction during microsurgery for recanalized intracranial aneurysms can be associated with high morbidity. We evaluated our preliminary experience using the clip-coil ratio to predict the need for coil extraction.
  
  
  METHODS
  A multi-institutional retrospective review of previously coiled aneurysms that were clipped for recurrence between 2005 and 2009 was performed. The maximal height and the widths of the recanalization were measured. The largest of these dimensions was divided by the other. We defined this as the clip-coil ratio, which is a modification of the aspect ratio.
  
  
  RESULTS
  Thirteen patients were included in this study. The mean age of the patients was 53 years (range 41-68 years). The aneurysm locations were anterior communicating artery (n = 5), pericallosal artery (n = 2), ophthalmic artery (n = 1), and posterior communicating artery (n = 5). A clip-coil ratio >or=1.3 allowed for microsurgical clipping without coil extraction. The mean ratio in these patients was 1.6. Coil extraction was necessary in two patients with a clip-coil ratio <1.3.
  
  
  CONCLUSIONS
  In reviewing our preliminary experience, we observed that coil extraction during microsurgery was not necessary when the clip coil ratio was >or=1.3. The ratio may serve as an indirect indicator of the amount of aneurysm tissue that can be incorporated within a clip; however, given the small patient population, further studies are needed to validate this concept.
authors.affiliation: Yale Department of Neurosurgery, Neurovascular Section, New Haven, CT 06520, USA. ketan.bulsara@yale.edu
authors.forename: Ketan R
authors.initials: KR
authors.lastname: Bulsara
authors.forename: Brian
authors.initials: B
authors.lastname: Hoh
authors.forename: Charles
authors.initials: C
authors.lastname: Rosen
authors.forename: Rokuya
authors.initials: R
authors.lastname: Tanikawa
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Carpenter
mesh_terms: D000328:Adult; D000368:Aged; D002533:Cerebral Angiography; D004621:Embolization, Therapeutic / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D005260:Female; D006801:Humans; D002532:Intracranial Aneurysm / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D008297:Male; D008866:Microsurgery / Q000295:instrumentation / Q000379:methods / Q000592:standards; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011183:Postoperative Complications / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D011379:Prognosis; D019736:Prostheses and Implants / Q000009:adverse effects* / Q000592:standards; D019919:Prosthesis Implantation / Q000009:adverse effects* / Q000295:instrumentation / Q000379:methods; D012008:Recurrence; D012086:Reoperation / Q000379:methods / Q000592:standards* / Q000706:statistics & numerical data; D012189:Retrospective Studies; D018570:Risk Assessment; D013525:Surgical Instruments / Q000592:standards / Q000706:statistics & numerical data; D016896:Treatment Outcome; D014656:Vascular Surgical Procedures / Q000295:instrumentation / Q000379:methods / Q000592:standards