Flow diverters failing to occlude experimental bifurcation or curved sidewall aneurysms: an in vivo study in canines

J Neurosurg. 2012 Jul;117(1):37-44. doi: 10.3171/2012.4.JNS111916. Epub 2012 May 4.


Object: Flow diverters (FDs) are increasingly used to treat complex intracranial aneurysms, but preclinical studies that could guide clinical applications are lacking. The authors designed a modular aneurysm model in canines to address this problem.

Methods: Three variants of one modular aneurysm model were constructed in 21 animals. Sidewall (n=5), curved sidewall (n=5), and end-wall bifurcation (n=7) aneurysms were treated with prototype 36-wire FDs. Four more end-wall bifurcation aneurysms were treated with prototype 48-wire lower-porosity FDs. Angiographic results postimplantation and at 3 months were scored with an ordinal scale. Animals were euthanized at 3 (n=17) or 6 (n=3) months, and the FD covering the aneurysm ostium was photographed to analyze metallic porosity and amount of neointima formation.

Results: Straight sidewall aneurysms were better occluded than curved sidewall and end-wall bifurcation aneurysms at the 3-month angiography follow-up (p=0.010). Flow diverters failed to occlude curved sidewall aneurysms (n=0/5) and all but one (n=1/7) end-wall bifurcation aneurysm. Angiographic results were no better (n=0/4) using a 48-wire FD (p=0.788). Branches jailed by the FD (n=16) remained patent in all cases. Metallic porosity was decreased (p=0.014) and neointimal closure of the aneurysm ostium was more complete (p=0.040) in sidewall aneurysms than in curved or bifurcation variants of the model.

Conclusions: Flow diverters may succeed in treating straight sidewall aneurysms, but the same device repeatedly fails to occlude curved sidewall and end-wall bifurcation aneurysms. In vivo studies can be designed to test basic principles that, once validated, may serve to guide clinical use of new devices.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cerebral Angiography
  • Disease Models, Animal
  • Dogs
  • Endovascular Procedures
  • Equipment Design
  • Equipment Failure
  • Intracranial Aneurysm / pathology*
  • Intracranial Aneurysm / surgery*
  • Intracranial Thrombosis / etiology
  • Neointima / pathology
  • Porosity
  • Stents* / adverse effects