Feasibility of MEMS-based hybrid coil-mesh flow diverter for intracranial aneurysms

Master of Science, Graduate Program in Mechanical Engineering
University of California, Riverside, June 2015
Dr. Masaru Rao, Chairperson

Flow  diversion  devices  have  generally  been  successful  in  the  treatment  of  intracranial aneurysms. However, clinical complications have often been linked to complex and counterintuitive mechanical responses which arise from the device’s braid-based design (e.g. poor wall  apposition, excessive foreshortening, etc.). Herein, as  a potential response to these issues, we demonstrate the feasibility of a novel microfabricated balloon-deployable flow diverter  with  finely  controlled  orthogonal  cross-sectional  elements  which  are monolithically integrated into a solid construct. Previous studies have mostly focused on characterizing  flow  diversion  as  a  result  of  porosity  in  highly  symmetric  devices.  By contrast,  here  we  show  that  similar results  can  be  achieved  in  more  sparse  and heterogeneous  structures  by  utilizing  basic  principles  of  aerodynamics  in  micro-scale design (i.e. intentionally designing structural elements to induce drag). Computational and experimental  models  suggest  the  potential  for  such  treatment,  noting an  average intra-aneurysmal  velocity  reduction  of  86%  and    88%  ±  4%  (n=3),  respectively  and reductions in average wall shear stress of 87% and 88% ± 4% (n=3). Experimental models showed  agreement  with  computational  models  with  the  model’s  predictive  metrics  for aneurysm occlusion falling within the 95% confidence interval for the experiments.