Patent Application
20230397913
The present invention generally relates to medical instruments, and more particularly, to embolic implants detachment mechanisms for aneurysm therapy.
Cranial aneurysms can be complicated and difficult to treat due to their proximity to critical brain tissues. Recently, tubular braided implants have been introduced that have the potential to treat an aneurysm or other arterio-venous malformation easily, accurately, and safely in a parent vessel without blocking flow into perforator vessels communicating with the parent vessel. Implant devices for treating aneurysms must be delivered through long, small, tortuous blood vessels and positioning must be controlled precisely to ensure aneurysm filling without causing additional occlusions or clotting in nearby vessels. Accordingly, it is necessary to have a delivery and detachment mechanism providing the connection point between a tubular braided implant and a delivery catheter that has the ability to deliver, position, manipulate, and then release the implant.
It is an object of the present invention to provide systems, devices, and methods to meet the above-stated needs. Generally, it is an object of the present invention to provide an endovascular detachment mechanism for an endovascular implant. An endovascular treatment system can include the endovascular detachment mechanism and the endovascular implant. The endovascular implant can have an open end and a pinched end. The detachment mechanism can include a connector that is positioned approximate the pinched end. The detachment mechanism can include a lock wire having a distal end engaged within the connector. The lock wire can include a threaded portion that can have a radius larger than the lock wire. The outer coil can surround the lock wire and can be engaged to the threaded portion. Axial rotation of the threaded portion can cause the lock wire to translate proximally with respect to the outer coil. The axial rotation can thereby disengage the distal end of the lock wire from the connector and release the endovascular implant.
In some examples, the connector can be a crimped ferrule.
In some examples, the lock wire distal end can be engaged with the connector with an interference fit.
In some examples, the distal end of the lock wire can have a tapered radius such that translating the lock wire proximally reduces the interference fit between the distal end of the lock wire and the connector.
In some examples, the outer coil can have a first spacing between coils at a proximal portion of the outer coil and a second spacing between coils at a distal portion of the outer coil. The second spacing can be greater than the first spacing.
In some examples, the endovascular treatment system can include a microcatheter that is sized to deliver the endovascular implant to a treatment site while the endovascular implant is in a non-deployed configuration.
In some examples, the lock wire is configured to push the endovascular implant through the microcatheter and to the treatment site.
In some examples, the threaded portion is welded to the lock wire.
In some examples, the endovascular implant can be configured to expand to a deployed configuration to occlude a spherical cavity.
In another aspect, an endovascular treatment system is disclosed. The endovascular treatment system can include an endovascular implant that includes an open end and a pinched end. The detachment mechanism can include a connector positioned approximate the pinched end. The detachment mechanism can include a lock wire having a distal end engaged within the connector. The detachment mechanism can include an inner coil that surrounds the lock wire and is affixed to the lock wire. The detachment mechanism can include an outer coil surrounding the inner coil. Axial rotation of the inner coil with respect to the outer coil can push a distal end of one of the inner coil or the outer coil against approximal end of the connector. The axial rotation can thereby cause the distal end of the lock wire to disengage from the connector to release the endovascular implant.
In some examples, the connector can be a crimped ferrule.
In some examples, the lock wire distal end can be engaged within the connector with an interference fit.
In some examples, the distal end of the lock wire can include a tapered radius such that translating the lock wire proximally can reduce the interference fit between the distal end of the lock wire and the connector.
In some examples, the endovascular treatment system can include a microcatheter that is sized to deliver the endovascular implant to a treatment site while the endovascular implant is in a non-deployed configuration.
In some examples, the lock wire can be configured to push the endovascular implant through the microcatheter and to the treatment site.
In another aspect, a method of constructing an endovascular implant detachment system is disclosed. The method can include providing an endovascular implant that has an open end and a pinched end. The method can include providing a lock wire having a distal end. The method can include welding a threaded portion having a radius larger than the lock wire to the lock wire. The method can include providing a connector positioned approximate the pinched end. The method can include fitting the distal end of the lock wire into the connector. The method can include threading an outer coil over the threaded portion of the lock wire such that axial rotation of the threaded portion is configured to cause the lock wire to translate proximally with respect to the outer coil. The axial rotation can thereby disengage the distal end of the lock wire from the connector and release the endovascular implant.
In some examples, providing the connector can further include crimping a ferrule to the pinched end of the endovascular implant.
In some examples, the connection between the connector and the distal end of the lock wire can be an interference fit.
In some examples, the distal end of the lock wire can include a tapered radius such that translating the lock wire proximally can reduce the interference fit between the distal end of the lock wire and the connector.
In some examples, the method can include providing a microcatheter sized to deliver the endovascular implant to a treatment site while the endovascular implant is in a non-deployed configuration.
The above and further aspects of this invention are further discussed with reference to the following description in conjunction with the accompanying drawings, in which like numerals indicate like structural elements and features in various figures. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating principles of the invention. The figures depict one or more implementations of the inventive devices, by way of example only, not by way of limitation.
Examples presented herein generally include a detachment mechanism that can be used with a braided implant that can be secured within an aneurysm sac and occlude a majority of the aneurysm's neck. The implant can include a tubular braid that can be set into a predetermined shape, compressed for delivery through a microcatheter, and implanted in at least one implanted position that is based on the predetermined shape and the geometry of the aneurysm in which the braid is implanted. When compressed, the implant can be sufficiently short to mitigate friction forces produced when the implant is delivered unsheathed through the microcatheter allowing for a more simplistic delivery system compared to some other known braided embolic implant delivery systems. The implant can be as described in U.S. Pat. No. 10,653,425, the entirety of which is incorporated herein by reference as if included in full.
The endovascular implant can include memory shape material that can be heat set to a predetermined shape, can be deformed for delivery through a catheter, and can self-expand to an implanted shape that is based on the predetermined shape and confined by the anatomy of the aneurysm in which it is implanted.
As illustrated in
In block 504, the method can include providing a lock wire 160 having a distal end 162.
In block 506, the method can include welding a threaded portion 166 to the lock wire. The threaded portion can have a radius larger than the lock wire 160.
In block 508, the method can include providing a connector 130 positioned approximate the pinched end 112. In some examples, the connector can be a ferrule that can be crimped to the lock wire. The ferrule can be constructed of any suitable material, such as a metal alloy.
In block 510, the method can include fitting the distal end 162 of the lock wire 160 into the connector 130. That is the distal end 162 of lock wire can be pushed into connector 130, and the connector 130 can be tightly crimped over the distal end of 162, thereby forming an interference fit.
In block 512, the method can include threading an outer coil 170 over the threaded portion 166 of the lock wire. The outer coil 170 can be rotated axially with respect to the threaded portion 166 such that the lock wire is translated proximally with respect to the outer coil 170. In response to the axial rotation, the distal end 162 of the lock wire 160 can disengage from the connector and release the endovascular implant 110.
The tubular braid of the example implant 110 can include memory shape material that can be heat set to a predetermined shape, can be deformed for delivery through a catheter, and can self-expand to an implanted shape that is based on the predetermined shape and confined by the anatomy of the aneurysm in which it is implanted.
The example implant described herein can rely on a radial outward force to anchor the implant within the sac of an aneurysm. To this end, the braid 110 can be shaped to a predetermined shape having a diameter that is greater than its height so that the braid is radially constricted when implanted in an aneurysm. The ratio of diameter to height of the braid 110 in a respective predetermined shape can be within the range of 2:1 to 1:3 to treat aneurysms of many known sizes and shapes.
The descriptions contained herein are examples of embodiments of the invention and are not intended in any way to limit the scope of the invention. As described herein, the invention contemplates many variations and modifications of the implant, including alternative materials, alternative geometries, alternative detachment features, alternative delivery systems, alternative means for forming a braid into a predetermined shape, alternative treatment methods, etc. These modifications would be apparent to those having ordinary skill in the art to which this invention relates and are intended to be within the scope of the claims which follow.
