Methods of intracerebral implant delivery

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

deploying an anchor of a tethering device in an anchoring vessel forming a first fixation point, wherein the tethering device has a tether extending proximally from the anchor and wherein the anchor allows blood to flow past the anchor in the anchoring vessel when deployed;

advancing a guide-sheath to a location near the first fixation point in the anchoring vessel, the guide-sheath having at least one lumen;

attaching the guide-sheath to the tether of the tethering device forming a second fixation point proximal to the first fixation point;

delivering the implant through the at least one lumen of the guide-sheath towards a treatment site distal to the first fixation point and located within an intracranial vessel, wherein delivering the implant through the at least one lumen tensions the tether between the first fixation point and the second fixation point; and

deploying the implant at the treatment site.

2. The method of claim 1 , wherein the implant is a balloon-expandable stent, a self-expanding stent, or a flow diverter.

3. The method of claim 1 , wherein the treatment site is an aneurysm or a stenosis.

4. The method of claim 1 , wherein the first fixation point is formed in the anchoring vessel near a bifurcation between the anchoring vessel and a vessel leading to the treatment site.

5. The method of claim 1 , wherein deploying the anchor comprises deploying the anchor from a low profile configuration to a higher profile configuration.

6. The method of claim 1 , wherein advancing the guide-sheath comprises advancing the guide-sheath over the tether such that the tether extends at least in part through the at least one lumen of the guide-sheath.

7. The method of claim 1 , wherein the guide-sheath comprises at least a second lumen, and the tether extends through at least a portion of the second lumen.

8. The method of claim 1 , wherein attaching the guide-sheath to the tether comprises using a tether gripper at the second point of fixation to attach the guide-sheath to the tether of the tethering device.

9. The method of claim 8 , wherein the tether gripper is on one or both of the tethering device and the guide-sheath.

10. The method of claim 1 , further comprising preventing prolapse of the guide-sheath during delivery of the implant.

11. The method of claim 1 , further comprising resisting tension stored in the guide-sheath during delivery of the implant.

12. The method of claim 1 , wherein the implant is a self-expanding stent and deploying the implant at the treatment site comprises unsheathing the self-expanding stent by withdrawing proximally a constraint.

13. The method of claim 12 , further comprising preventing the self-expanding stent from missing the treatment site during unsheathing.

14. The method of claim 1 , further comprising removing the anchor from the anchoring vessel; and removing the guide-sheath.

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

delivering a tethering device to an anchoring vessel, 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, the anchor configured to allow at least partial blood flow through 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;

forming a second fixation point proximal to the anchoring vessel by attaching the guide-sheath to the tether; and

delivering the implant through the guide-sheath to a treatment site distal to the anchoring vessel, wherein delivering the implant through the guide-sheath tensions the tether between the anchor deployed in the anchoring vessel and the second fixation point.

16. The method of claim 15 , wherein the tethering device fixes and supports the guide-sheath for delivering the implant through the guide-sheath.

17. The method of claim 15 , wherein the anchor is deployed at an anchoring site in the anchoring vessel.

18. The method of claim 15 , wherein the guide-sheath includes a lumen to receive at least a portion of the tether.

19. The method of claim 18 , wherein the implant is delivered through a first lumen of the guide-sheath and the tether extends at least in part through the first lumen.

20. The method of claim 18 , wherein the implant is delivered through a first lumen of the guide-sheath and the tether extends at least in part through a second lumen separate from the first lumen.

21. The method of claim 15 , wherein the implant is a balloon-expandable stent, a self-expanding stent, or a flow diverter.

22. The method of claim 15 , wherein the treatment site is an aneurysm or a stenosis.

23. The method of claim 15 , further comprising preventing prolapse of the guide-sheath during delivery of the implant.

24. The method of claim 15 , further comprising resisting tension stored in the guide-sheath during delivery of the implant.

25. The method of claim 15 , wherein the implant is a self-expanding stent and deploying the implant at the treatment site comprises unsheathing the self-expanding stent by withdrawing proximally a constraint.

26. The method of claim 25 , further comprising preventing the self-expanding stent from missing the treatment site during unsheathing.

27. The method of claim 15 , further comprising removing the anchor from the anchoring vessel; and removing the guide-sheath.