Methods of intracerebral implant delivery

A method of delivering an expandable implant in an intracranial vessel, the method comprising:

• advancing a guidewire near an anchoring vessel;
• exchanging the guidewire for a tethering device, wherein the tethering device includes a tether extending proximally from an anchor;
• deploying the anchor of the tethering device in the anchoring vessel forming a first fixation point, wherein the anchor allows blood to flow past the anchor in the anchoring vessel when deployed;
• advancing a guide-sheath over the tether of the tethering device to position an opening from the guide-sheath near an entrance of a target vessel bifurcating from the anchoring vessel;
• attaching the guide-sheath to the tether of the tethering device forming a second fixation point proximal to the first fixation point;
• and
• delivering an implant through the guide-sheath to a treatment site distal to the first fixation point within an intracranial vessel.