“…In trapping cases, the ICA was occluded in the petrous region or neck, as well as intracranially immediately distal to the aneurysm. Proximal occlusion was likely to be less effective because of large collateral back fl ow to the aneurysm via the ophthalmic artery [11] . Thus, craniotomy for proximal ICA ligation is necessary for proximal trapping cases.…”