Stents twisted prior to deployment and untwisted during deployment
Stents can become twisted during deployment within tortuous vessels such that proper expansion against the vessel wall is inhibited. Stents can be twisted prior to deployment in a direction opposite the direction of twisting during deployment to facilitate full expansion of the stent against the vessel wall along the stent's entire length.
1. A method for placing a stent within an intracranial vessel, the method comprising:
(a) providing a stent comprising a first end, a second end, and a tubular, mesh wall between the first end and the second end, the mesh wall being contiguous in circumferential and longitudinal directions from the first end to the second end, the stent having a rest configuration in the absence of external forces, and a twisted configuration in which the stent is (i) collapsed toward a longitudinal axis of the stent from the rest configuration and (ii) twisted about the longitudinal axis from the rest configuration;
(b) advancing a catheter toward the intracranial vessel while twisting the catheter, and advancing the stent through the catheter into the intracranial vessel while holding the stent in the twisted configuration;
(c) expanding the first end of the stent against a wall of the intracranial vessel, comprising retracting the catheter, from a position where the catheter extends over an entire length of the stent, to expose the first end of the stent to expand the first end of the stent;
(d), after (c), untwisting the stent while untwisting the catheter and while expanding portions of the mesh wall of the stent progressively farther from the first end, comprising retracting the catheter toward the second end of the stent while rotating a distal end of the catheter; and
(e) expanding the second end of the stent against the wall of the intracranial vessel.
2. The method of claim 1 , wherein the distal end of the catheter is rotated while retracting a proximal end of the catheter without significant rotation of the proximal end of the catheter.
3. The method of claim 1 , wherein the distal end of the catheter is rotated at least 180 degrees about a longitudinal axis of the catheter from (c) to (e) while rotating the proximal end of the catheter less than 180 degrees.
4. The method of claim 1 , wherein the distal end of the catheter is rotated at least 360 degrees about a longitudinal axis of the catheter from (c) to (e) while rotating the proximal end of the catheter less than 180 degrees.
5. The method of claim 1 , wherein the stent is advanced into the intracranial vessel while the stent is twisted more than is necessary to collapse the stent.
6. The method of claim 5 , wherein the stent is only partially untwisted from (c) to (e).
7. The method of claim 1 , wherein the stent has a length of at least 50 mm, and the stent is expanded within the intracranial vessel without a kink.
8. The method of claim 7 , wherein the stent is expanded within the intracranial vessel such that a minimum transverse inside dimension of the stent is at least 50% of a maximum transverse inside dimension of the stent.
9. The method of claim 7 , wherein an entire circumference of the stent along an entire length of the mesh wall of the stent is expanded into contact with the wall of the intracranial vessel.
10. A method of treating a patient having a neurovascular condition, comprising:
providing a plurality of stents, each stent of the plurality of stents comprising first end and a second end, and having a rest configuration in the absence of external forces, and a twisted configuration in which the stent is (i) collapsed toward a longitudinal axis of the stent from the rest configuration and (ii) twisted about the longitudinal axis from the rest configuration, each stent held in the twisted configuration, the plurality of stents comprising (a) a stent twisted in a first rotational direction about the longitudinal axis, and (b) a stent twisted in a second rotational direction, opposite the first rotational direction, about the longitudinal axis;
identifying a location for placement of a stent within the patient's neurovasculature;
selecting, based on the location for placement and from among the plurality of stents, between (a) the stent twisted in the first rotational direction, and (b) the stent twisted in the second rotational direction;
placing the selected stent in the neurovasculature; and
expanding the selected stent within the neurovasculature.
11. The method of claim 10 , wherein the plurality of stents comprises stents of various amounts of twist, and wherein the selected stent is selected, based on the neurovasculature at the location of placement, to have one of the various amounts of twist.
12. The method of claim 10 , wherein the plurality of stents comprises stents of various lengths, and wherein the selected stent is selected, based on the neurovasculature at the location of placement, to have one of the various lengths.
13. The method of claim 10 , wherein the plurality of stents comprises stents of various transverse dimensions, and wherein the selected stent is selected, based on the neurovasculature at the location of placement, to have one of the various transverse dimensions.
14. The method of claim 10 , wherein the stent is configured for self-expansion, and (b) comprises advancing the stent through a catheter, (c) comprises retracting a distal end of the catheter to expose the first end of the stent to expand the first end of the stent, and (d) comprises retracting the distal end of the catheter toward the second end of the stent while rotating the distal end of the catheter.