Embolization coil proximal connection element and stretch-resistant fiber

Abstract

To provide an embolic implant.SOLUTION: An embolic coil implant having a stretch resistant fiber therethrough and a dual-functional engagement feature at its proximal end is provided. The stretch resistant fiber can be effective to limiting separation of windings of the embolic coil. The engagement feature can provide an attachment for securing the embolic coil to an engagement system of a delivery tube and for securing the stretch resistant fiber at the proximal end of the embolic coil. The engagement feature can have two engagement surfaces affixed to a proximal end of the embolic coil that are longitudinally offset from each other by a distance that is about half of a diameter of a wire of the embolic coil.SELECTED DRAWING: Figure 1A

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application is a continuation - in - part of U.S. Patent Application No. 16 / 573,469, filed on September 17, 2019, and is incorporated herein by reference in its entirety as fully described herein.

[0002] (Field of the Invention) The present invention generally relates to implantable medical devices, and more specifically to engagement features for mechanically and releasably securing an implantable medical device to a delivery system.

Background Art

[0003] Aneurysms can be treated endovascularly by delivering a treatment device to the aneurysm, filling the aneurysm sac with an embolization material, and / or occluding the neck of the aneurysm to suppress blood flow to the aneurysm. When filling the aneurysm sac, the embolization material may promote blood clotting and create a thrombotic mass within the aneurysm. When treating the aneurysm neck without substantially filling the aneurysm sac, blood flow to the aneurysm neck can be suppressed, inducing venous congestion within the aneurysm and facilitating the natural formation of a thrombotic mass within the aneurysm.

[0004] In some current treatments, multiple embolic coils are used to either fill the aneurysm sac or treat the entrance to the aneurysm neck. A common challenge during embolic coil treatment is that the implanted portions of implanted and partially implanted coils become entangled, making repositioning difficult. In some cases, physicians may be unable to retract partially implanted coils and may be forced to position coils in less-than-ideal locations. Embolic coils that are improperly positioned in the aneurysm neck can potentially have adverse effects, such as obstructing blood flow when joining to the vessel, especially if the entrance and / or sac is overfilled. If a portion of a non-ideally implanted coil is removed, that portion may enter an adjacent vessel, promoting clot formation, and ultimately becoming tethered to the aneurysm, potentially causing a very difficult-to-treat occlusion. Conversely, if the entrance and / or sac is not sufficiently filled, blood flow may remain trapped within the aneurysm.

[0005] In some current treatments, the embolization coil is attached to a tubular delivery member and delivered to the aneurysm via a delivery catheter. During delivery, the embolization coil may engage with an implant engagement / deployment system (collectively referred to herein as “engagement system” or “deployment system”) of the delivery member. When the embolization coil is in place, the deployment system can release the coil, leaving the coil implanted, and retract the delivery member. Some treatments utilize a mechanical engagement / deployment system that can be operated by a physician to release the implant by pulling one or more wires or other extended members collectively referred herein as “pull wires”.

[0006] Some of the challenges associated with the delivery and deployment of embolization coils equipped with a delivery member having a mechanical engagement system include premature release of the coil and displacement of the delivery member due to pushback from a densely packed treatment site. [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] Therefore, there is a need for improved methods, devices, and systems to facilitate the implantation of embolic coils and other implants that face similar challenges. [Means for solving the problem]

[0008] The object of the present invention is to provide systems, apparatus, and methods that satisfy the above-described needs. In some embodiments presented herein, separation of the coil windings within the embolic coil is reduced or prevented by stretch-resistant fibers positioned within the lumen of the coil. Reducing or preventing the separation of the coil windings can, in some cases, prevent the implanted portion of a partially implanted coil from becoming entangled with the implanted coil, thereby allowing for easier repositioning and / or extraction of part or all of the coil. In some embodiments presented herein, during delivery of the embolic coil, the distal end of the pull wire is supported by an engagement / disengagement feature (collectively referred to herein as “engagement feature,” “disengagement feature,” or “key”) attached to the proximal end of the embolic coil. The support provided by the key can, in some cases, reduce the possibility of premature release of the embolic coil. In some examples presented herein, the embolic implant may have a highly flexible proximal portion. The flexibility of the embolization implant can, in some cases, reduce the force on the delivery member due to the pushback from the densely filled treatment site, thereby reducing the movement of the delivery member due to the pushback.

[0009] To meet some or all of the requirements, an implant having an embolization coil, a stretch-resistant fiber extending through the coil, and a detachment feature / key at the proximal end of the coil are provided. The stretch-resistant fiber may be effective in limiting the separation of the windings of the embolization coil. The key may provide an attachment for securing the embolization coil to the engagement system of the delivery tube and for securing the stretch-resistant fiber at the proximal end of the embolization coil.

[0010] Exemplary methods for treating an aneurysm may include one or more of the following steps, presented in no particular order, and the method may include additional steps not included herein. Part or all of an implant having an embolic coil and stretch-resistant fibers can be positioned within the aneurysm. Part of the embolic coil can be retracted from the aneurysm. When this part is retracted from the aneurysm, the stretch-resistant fibers can prevent elongation of this part. The embolic coil can be bent, and the stretch-resistant fibers can limit the separation of the windings of the embolic coil when bent.

[0011] The stretch-resistant fibers can be positioned to extend within the lumen of the embolization coil. The stretch-resistant fibers may be under tension along most of their length.

[0012] The implant can be secured to the delivery system with a key engaged with a stretch-resistant fiber. To secure the implant to the delivery system, the loop wire of the delivery system can be positioned through the key, and the pull wire can be positioned through an opening in the loop wire. When the implant is secured to the delivery system, the pull wire can be supported by the key both proximal and distal to the loop wire.

[0013] The key can be visualized by X-ray during implant delivery and / or positioning.

[0014] The key can be released from the delivery system, thereby releasing the implant from the delivery system. The key can remain attached to the implant when it is released.

[0015] An exemplary embolic implant may include an embolic coil, a detachable feature, and a stretch-resistant fiber. The detachable feature may be attached to the embolic coil at its proximal end. The stretch-resistant fiber may engage with the detachable feature, extend through the lumen of the embolic coil, and be attached to the embolic coil at its distal end. In this configuration, the stretch-resistant fiber may be effective in limiting the separation of the windings of the embolic coil when the embolic coil is reshaped.

[0016] Stretch-resistant fibers can be used for sutures. Stretch-resistant fibers can be inelastic.

[0017] The desorption feature area may be radiopaque.

[0018] The detachment feature may have an opening through which stretch-resistant fibers pass. The opening may extend proximal to the proximal end of the embolic coil.

[0019] The detachment feature may have a single opening sized to accommodate the loop wire of the mechanical delivery system and through which the stretch-resistant fiber passes.

[0020] Alternatively, the detachment feature may have two distinct openings: a first opening through which stretch-resistant fibers pass, and a second opening sized to receive a loop wire of a mechanical delivery system. The first opening may be at least partially positioned within the lumen of the embolic coil. The second opening may be at least partially positioned proximal to the proximal end of the embolic coil.

[0021] An exemplary system may include an exemplary embolic implant having a detachment feature comprising two separate openings and a mechanical delivery system including a loop wire and a pull wire. A stretch-resistant fiber can pass through one of the two openings, and the loop wire can pass through the other of the two openings. The pull wire is positioned through the opening of the loop wire, thereby allowing the implant to be secured to the mechanical delivery system with the loop wire. The detachment feature may further include a bridge positioned between the two openings of the detachment feature, the bridge being able to support a portion of the pull wire distal to the loop opening of the loop wire.

[0022] The detachment feature may have a proximal portion located proximal to the lumen of the embolic coil and a distal portion located within the lumen. The proximal portion may have a width larger than the inner diameter of the embolic coil lumen, and the distal portion may have a width approximately equal to the inner diameter of the embolic coil lumen.

[0023] Exemplary methods for constructing or designing an embolization implant, such as the exemplary implants described herein, may include one or more of the following steps, presented in no particular order, and the methods may include additional steps not included herein. A detachment feature may be cut from a flat sheet material. One or more openings may be cut from the detachment feature. Stretch-resistant fibers may be passed through the openings of the detachment feature. Stretch-resistant fibers may extend through the lumen of the embolization coil. The detachment feature may be attached to one end of the embolization coil. Stretch-resistant fibers may be attached to the other end of the embolization coil. Tension can be provided between the detachment feature and the second end of the embolization coil along the stretch-resistant fibers.

[0024] A portion of the mechanical deployment system can extend through the opening of the detachment feature to engage the detachment feature with the delivery tube. The mechanical deployment system can extend through the opening of the detachment feature that is the same opening through which the stretch-resistant fiber passes internally, or separate from the opening through which the stretch-resistant fiber passes internally.

[0025] The detachment feature can be cut from a radiopaque flat sheet material.

[0026] The distal portion of the detachment feature can be inserted into the lumen of the plug coil, and the proximal portion of the detachment feature can extend proximally from the proximal end of the plug coil. The plug coil and the detachment feature can be selected such that the proximal portion of the detachment feature is wider than the inner diameter of the lumen of the plug coil, and the distal portion of the detachment feature is approximately equal to the inner diameter of the lumen of the plug coil.

[0027] To adhere the detachment feature to the plug coil, the detachment feature can be welded to the plug coil.

Brief Description of the Drawings

[0028] The above and further aspects of the present invention will be further considered in conjunction with the following description and the accompanying drawings, in which like numbers indicate like structural elements and features in the various drawings. The drawings are not necessarily to scale and instead are focused on illustrating the principles of the present invention. The figures depict one or more implementations of the device of the present invention as illustrative examples rather than as limitations. [Figure 1A] An illustration of a plug implant according to an aspect of the present invention. [Figure 1B] An illustration of a plug implant according to an aspect of the present invention. [Figure 2A] An illustration of a detachment feature through which stretch-resistant fibers are passed according to an aspect of the present invention. [Figure 2B] An illustration of a detachment feature through which stretch-resistant fibers are passed according to an aspect of the present invention. [Figure 3]This is an example of a stretch-resistant fiber inserted into the lumen of an embolization coil according to an aspect of the present invention. [Figure 4] This is an example of a stretch-resistant fiber exiting the lumen of an embolization coil according to an aspect of the present invention. [Figure 5A] This is an example of a detachable feature portion inserted into the lumen of an embolization coil according to an aspect of the present invention. [Figure 5B] This is an example of a detachable feature portion inserted into the lumen of an embolization coil according to an aspect of the present invention. [Figure 6A] This is an example of a detachable feature attached to an embolization coil according to an aspect of the present invention. [Figure 6B] This is an example of a detachable feature attached to an embolization coil according to an aspect of the present invention. [Figure 7] This is an example of a stretch-resistant fiber attached to the end of an embolization coil according to an aspect of the present invention. [Figure 8A] This illustrates the time sequence in which embolic coils stretch as a result of the placement of suboptimal stretch-resistant fibers. [Figure 8B] This illustrates the time sequence in which embolic coils stretch as a result of the placement of suboptimal stretch-resistant fibers. [Figure 8C] This illustrates the time sequence in which embolic coils stretch as a result of the placement of suboptimal stretch-resistant fibers. [Figure 9] This is an example of an embolization coil positioned within an aneurysm according to an aspect of the present invention. [Figure 10A] This is an example of entangled embolization coils. [Figure 10B] An example of a problem caused by prior art is an example of an entangled coil in an extended state. [Figure 11] This is an example of a stretch-resistant fiber that suppresses entanglement and elongation of embolic coils according to an aspect of the present invention. [Figure 12] This flowchart outlines a method and process that may be performed as part of aneurysm treatment according to an aspect of the present invention. [Figure 13] This is an example of an embolization implant fixed to a delivery tube according to an aspect of the present invention. [Figure 14A] This illustrates a series of steps for releasing an embolization implant from a delivery tube according to an aspect of the present invention. [Figure 14B] This illustrates a series of steps for releasing an embolization implant from a delivery tube according to an aspect of the present invention. [Figure 14C] This illustrates a series of steps for releasing an embolization implant from a delivery tube according to an aspect of the present invention. [Figure 14D] This illustrates a series of steps for releasing an embolization implant from a delivery tube according to an aspect of the present invention. [Figure 15] This is an example of the end portion of an embolization implant having a detachable feature portion that expands the inner diameter of the embolization coil, according to an aspect of the present invention. [Figure 16] This is a diagram illustrating another exemplary detachment feature according to an aspect of the present invention. [Figure 17A] This is a diagram illustrating an exemplary detachment feature according to an embodiment of the present invention. [Figure 17B] This is a diagram illustrating an exemplary detachment feature according to an embodiment of the present invention. [Figure 17C] This is a diagram illustrating an exemplary detachment feature according to an embodiment of the present invention. [Figure 17D] This is a diagram illustrating an exemplary detachment feature according to an embodiment of the present invention. [Figure 17E] This is a diagram illustrating an exemplary detachment feature according to an embodiment of the present invention. [Figure 17F] This is a diagram illustrating an exemplary detachment feature according to an embodiment of the present invention. [Figure 17G] This is a diagram illustrating an exemplary detachment feature according to an embodiment of the present invention. [Figure 17H] This is a diagram illustrating an exemplary detachment feature according to an embodiment of the present invention. [Figure 18] This figure shows the proximal portion of an exemplary desorption feature shown in Figure 16, according to an aspect of the present invention. [Modes for carrying out the invention]

[0029] The object of the present invention is to achieve more accurate and repeatable implant detachment. More specifically, the object of the present invention is to facilitate the implantation of embolic coils and other implants, which face challenges such as difficulty in repositioning partially implanted implants, displacement of the delivery system due to being pushed back during implantation, and / or premature release of the implant. To satisfy some or all of these needs, exemplary implants may include stretch-resistant fibers for limiting stretching and other deformation of the embolic portion of the implant (e.g., the embolic coil), and a detachment feature to which the stretch-resistant fibers can be fixed and to which the delivery system can be detachably attached.

[0030] To facilitate implant repositioning, stretch-resistant fibers extend through the embolization coil, limiting the separation of the coil windings when the coil is bent and pulled. By limiting winding separation, the embolization coil is less likely to entangle when partially implanted and less likely to stretch or deform otherwise when retracted when partially implanted. This allows for easier repositioning of the embolization coil. In some embodiments, the detachment feature may include two separate openings, one for securing the stretch-resistant fibers and the other for engaging with the engagement system. The dual-opening detachment feature provides reliable positioning of the stretch-resistant fibers, and thus can reduce potential manufacturing challenges in more reliably providing an implant that can be more easily repositioned.

[0031] To reduce the effect of pushback during implantation, the detachment feature can be sized to provide an embolization coil implant with a highly flexible proximal section and attached to the embolization coil. The embolization coil implant with a highly flexible proximal section reduces the pushback force on the delivery tube and thereby reduces the effect of the delivery tube shifting. Additionally or alternatively, the detachment feature can be sized to interlock with a delivery tube having a highly flexible distal section, and the highly flexible distal section of the delivery tube can reduce the effect of the delivery tube shifting. When an embolization coil implant with a highly flexible proximal section interlocks with a delivery tube having a highly flexible distal portion, the combination of the flexible distal section of the delivery tube and the flexible proximal section of the implant can further reduce the effect of the delivery tube shifting.

[0032] To reduce instances of premature deployment, the detachment feature may include a bridge for supporting the pull wire. The detachment feature can be detachably attached to the mechanical engagement / deployment system on the delivery tube. The detachment feature may include an opening through which the loop wire of the mechanical engagement system can pass. In some embodiments, the detachment feature may further include a bridge positioned distal to the opening on which the distal portion of the pull wire can be placed. The bridge, through engagement with the loop wire, can prevent deformation of the pull wire, thereby reducing the possibility of premature implant release due to bending of the pull wire.

[0033] Figure 1A illustrates an example of an implant 10a comprising an embolization coil 12 having a lumen 13 through which it passes, a detachable feature 18a, and a stretch-resistant fiber 16. A portion of the coil 12 and weld 42 are illustrated in a cutaway for illustrative purposes. The detachable feature 18a can be partially positioned within the lumen 13 of the coil 12 and can extend outward from the coil 12. The detachable feature 18a may include a distal opening 24a through which the stretch-resistant wire 16 is looped, and a proximal opening 22a sized to receive the loop wire or other engagement mechanism of a mechanical implant engagement system. The detachable feature 18a may include a bridge 28a positioned between the distal opening 24a and the proximal opening 22a. The detachable feature 18a may include a proximal tab 38 sized to fit into the lumen of a delivery tube. The stretch-resistant fiber 16 can be fixed to the end of the embolus coil 12 on the opposite side of the end where the detachable feature portion 18a is attached by a weld 44 or other suitable attachment point.

[0034] The detachment feature 18a can be tapered to extend further into the lumen 13 of the embolic coil 12, allowing the embolic coil 12 to have additional flexibility surrounding the tapered region. The detachment feature 18a can also have a substantially flat contour, providing even greater flexibility in the in-plane and out-of-plane directions of the image.

[0035] The detachable feature 18a can be securely fixed to the coil 12 using the attachment 42 without fusing any of the coil 12 windings (as illustrated), or by fusing a small number of windings (e.g., five or four or fewer windings). Compared to known solutions in which typically 10 or 11 or more windings are soldered together (with limited control over the number of windings fused), the attachment 42 to the coil 12 can be realized using significantly fewer fused coil windings. By reducing the number of windings fused, the proximal section of the implant 10a can have greater flexibility compared to known designs that rely on fusing windings from the proximal end of the embolization coil.

[0036] Figure 1B is an example of an alternatively constructed implant 10b having elements described in relation to Figure 1A, which have similar reference numerals indicating similar elements. A portion of the coil 12 and weld 42 are illustrated in a cutaway for illustrative purposes. Compared to the implant 10a illustrated in Figure 1A, implant 10b may have an alternative detachment feature 18b having a single opening 26b that provides an opening through which a mechanical engagement system can be engaged and through which stretch-resistant fibers 16 can be looped. The detachment feature 18b illustrated in Figure 1B also lacks the extending tapered region of the detachment feature 18a illustrated in Figure 1A. The tapered region of the detachment feature 18a illustrated in Figure 1A may provide a more flexible proximal section of the implant 10a compared to the implant 10b in Figure 1B. Nevertheless, the detachment feature 18b illustrated in Figure 1B, being flat, provides flexibility in the in-plane and out-of-plane directions of the image, thereby providing higher flexibility than known embolic coil implants, and the low-profile attachment portion 42 can provide higher flexibility than designs that rely on fusion of the winding from the proximal end of the embolic coil.

[0037] Figures 2A and 2B to 7 illustrate a series of steps for constructing the implants 10a and 10b illustrated in Figures 1A and 1B. Figures 2A and 2B illustrate the stretch-resistant fibers 16 passing through the detachment features 18a and 18b. The detachment features 18a and 18b can be laser-cut from a flat sheet material. The flat sheet material is preferably a radiopaque material that can be welded to or otherwise attached to the embolization coil 12.

[0038] Figure 2A illustrates a double-opening detachable feature 18a having a proximal portion 32 sized to engage with a mechanical engagement system and / or a delivery tube. The proximal portion 32 is illustrated as having a width W1. The double-opening detachable feature 18a may have a distal portion 34 sized to fit into the lumen 13 of the embolic coil. The distal portion 34 may have a wider section having a width W2 approximately the same as the inner diameter of the embolic coil 12, and a tapered section having a width W3 significantly narrower than the inner diameter of the embolic coil 12. The detachable feature 18a may have a proximal tab 38 that is narrower than the proximal portion 32 and sized to fit into the lumen of the delivery tube.

[0039] Figure 2B illustrates a single-opening / detachable feature 18b having a proximal portion 32 sized to engage with a mechanical engagement system and / or a delivery tube. The proximal portion 32 is illustrated to have a width W1. The single-opening / detachable feature 18b may have a distal portion 34b that is narrower than the proximal portion 32 and sized to fit into the lumen 13 of the coil 12. The single-opening / detachable feature 18b may have a proximal tab 38 that is narrower than the proximal portion 32 and sized to fit into the lumen of the delivery tube.

[0040] After the detachment features 18a and 18b are formed, the stretch-resistant fibers 16 can be passed through the distal opening 24a of the double-opening detachment feature 18a or the single opening 26b of the single-opening detachment feature 18b.

[0041] Figure 3 shows an example of the free end of a stretch-resistant fiber 16 inserted into the proximal end 15 of the embolus coil 12. In the process illustrated in Figure 3, the stretch-resistant fiber 16 can be made into a loop by passing through detachable feature portions 10a and 10b as illustrated in Figures 2A and 2B.

[0042] Figure 4 shows an example of the free end of the stretch-resistant fiber 16 that exits the lumen 13 of the embolic coil 12 at the distal end 14 of the embolic coil 12.

[0043] Figures 5A and 5B illustrate the detachable features 18a and 18b inserted into the lumen 13 of the embolic coil 12. After exiting the distal end 14 of the embolic coil 12, the free end of the stretch-resistant fiber 16 can be further pulled, as indicated by the arrow in Figure 4, to move the detachable features 18a and 18b into the lumen 13 of the embolic coil 12 at the proximal end 15, as illustrated in Figures 5A and 5B and by the arrow. Before the detachable features 18a and 18b enter the lumen 13 of the embolic coil 12, the embolic coil may have an inner diameter D as shown in Figure 5A. The proximal portion 34 of the detachable features 18a and 18b can be sized to have a width greater than at least a portion of the distal portion 34, which is approximately equal to the inner diameter D, for a sliding fit. Alternatively or additionally, at least a portion of the distal portion 34 may have a width greater than the diameter D to create an interference fit. Alternatively or additionally, at least a portion of the distal portion 34 may have a width smaller than the diameter D to allow for greater flexibility of the coil 12 near the proximal end 15 of the coil 12.

[0044] Figures 6A and 6B illustrate the detachable feature portions 10a and 10b with the distal portion 34 fully inserted into the lumen 13 of the embolic coil 12, and the detachable feature portions 18a and 18b attached to the embolic coil 12 by a welded portion 42 or other attachment. In both Figures 6A and 6B, the detachable feature portions 18a and 18b are illustrated with a distal portion 34 having a width exceeding at least a portion of the length of the distal portion 34, which is approximately equal to the inner diameter D of the lumen 13 of the embolic coil 12.

[0045] Figure 7 shows an example of a stretch-resistant fiber 16 attached to the distal end of the embolic coil 12. After attaching the detachment features 18a, 18b, or at least after positioning the detachment features 18a-18b as illustrated in Figures 6A and 6B, the stretch-resistant fiber 16 can be tightly pulled to reduce slack within the fiber 16 and / or create tension within the fiber 16, and the fiber 16 can be attached at the weld 44 or other attachment point. After the fiber 16 is attached, the fiber can become substantially stretch-resistant to resist significant elongation due to forces applied to the embolic coil 12 during treatment preparation, delivery of implants 10a, 10b, positioning of the implant at the treatment site, retraction of the implant, and deployment of the implant. In other words, the stretch-resistant fibers 16 may be effective in limiting the elongation of the embolic coil 12 when retracting the embolic coil 12 from the aneurysm, and the stretch-resistant fibers 16 may be effective in limiting the separation of the windings within the embolic coil 12 when the embolic coil 12 is bent.

[0046] Figures 8A to 8C illustrate a time sequence in which the embolic coil 12 can be stretched as a result of the implantation of suboptimal stretch-resistant fibers 16. Figure 8A illustrates the implantation of suboptimal fibers 16 within a single-opening detachment feature 18b. The fibers 16 can be looped over a suboptimal section of the detachment feature 18b, thereby allowing the fibers 16 to be disengaged from a suboptimal position by movement of the fibers 16, as illustrated in Figure 8B, and allowing the embolic coil 12 to be stretched until at least the fibers 16 re-engage with the detachment feature 18a by movement of the fibers 16, as illustrated in Figure 8C. Therefore, a manufacturing challenge is to prevent the fibers 16 from being positioned in a suboptimal location, as illustrated in Figure 8A, when the installation process illustrated in Figure 7 is performed. If, after manufacturing is complete, the fibers 16 are removed from a suboptimal location, as illustrated in Figure 8B, the embolization coil 12 can be stretched or otherwise deformed, as illustrated in Figure 8C, while manipulating the implant 10b, such as during repositioning during treatment.

[0047] An advantage of the double-opening detachment feature 18a is that, during the manufacturing of the implant 10a illustrated in Figure 1A, the stretch-resistant fibers 16 are less likely to form loops on suboptimal sections of the detachment feature 18a.

[0048] Figure 9 shows an example of embolic implants 10 delivered through a delivery catheter 200 and positioned within aneurysm A of vascular vessel BV. The implants may loop and bend within the aneurysm sac to form a thrombotic mass. The implants may loop back into themselves and / or adjacent loops of other implants. As aneurysm A is gradually filled, overlapping portions of the implants 10 may be pushed into one another.

[0049] Figure 10A illustrates an embolic coil 12 in which the stretch-resistant fibers 16 do not entangle when the overlapping portions of the coil are pressed together. This entanglement can make it difficult or impossible to reposition any of the coils 12, which is a known problem with some current embolic coil implants. Figure 10B illustrates a portion of the embolic coil 12 that, due to a force F, is stretched to a length L2 that is longer than the length L1 of the section illustrated in Figure 10A. Figure 10B illustrates a scenario in which a physician may attempt to retract an entangled, partially implanted embolic coil, which may not only be unable to retract the coil but may also exacerbate an already difficult treatment by requiring repositioning of the deformed, stretched coil. The likelihood of entanglement may increase when the windings of the embolic coil are separated, for example, by bending, or when the coil is compressed more densely by high-density filling.

[0050] Figure 11 illustrates exemplary embolic coils 12 according to one aspect of the present invention, each having a stretch-resistant fiber 16 that prevents entanglement and stretching. Each coil 12 is illustrated as having a bend portion 20. The stretch-resistant fiber 16 can shift within the lumen 13 of each coil to allow the coil 12 to bend and flex as needed when implanted. The fiber 16 may have sufficient tension to limit the amount of separation between the windings of the bend portion 20. The separation of the windings may be limited to prevent entanglement of the windings of two adjacent coils 12, as illustrated in Figure 10A. Figure 11 also illustrates a force F applied to a portion 40 of the coil 12, where the tension within the stretch-resistant fiber 16 prevents the portion 40 from stretching. Figure 11 illustrates a scenario in which a physician can successfully retract a partially implanted embolic coil 12 through which the stretch-resistant fiber 16 is threaded.

[0051] Figure 12 is a flowchart illustrating Method 500, which may be performed as part of an aneurysm treatment using exemplary implants 10, 10a, and 10b as described herein. In step 510, the implant having an embolization coil and stretch-resistant fibers can be positioned at least partially within the aneurysm sac. In step 520, a portion of the embolization coil can be bent. In step 530, as the coil is bent, the stretch-resistant fibers may prevent the windings within the bent portion of the embolization coil from separating. In step 540, part or all of the implanted portion of the implant can be retracted from the aneurysm. In step 550, as the implant is retracted, the stretch-resistant fibers may prevent the elongation of the embolization coil.

[0052] Figure 13 illustrates an exemplary embolization implant 10, such as those illustrated in Figures 1A and 1B, or any of the implants 10a and 10b described herein, fixed to a delivery tube 300. Exemplary delivery tubes and engagement / deployment systems are described in U.S. Patents 10,806,461 and 10,806,462, which are incorporated herein by reference, respectively. The delivery tube 300 may include a notch 310 sized to receive the proximal portion 32 of the detachment feature 18 of the implant 10, and similarly, the proximal portion 32 of the detachment feature 18 may be sized to fit into the notch 310 of the delivery tube 300. Figure 13 illustrates a side view of the implant 10, highlighting the flat contour of the detachment feature 18. As described in relation to Figures 1A and 1B, the implant 10 may have a highly flexible proximal portion by having a flat detachable feature 18 and / or by having the detachable feature 18 fixed to the coil 12 without fusing some coil windings. The detachable feature 18 may also be tapered so that its flexibility increases in the in-plane and out-of-plane directions of the image. The detachable feature 18 may further include a proximal tab 38 positioned within the lumen of the delivery tube 300.

[0053] During aneurysm occlusion treatment, a lack of flexibility in the proximal portion of known embolization implants and / or a lack of flexibility in the distal portion of the delivery tube can cause the delivery tube to be pulled back from the treatment site or otherwise displaced while the implant is in place within the aneurysm. Therefore, a delivery tube having a more flexible distal portion and an implant having a more flexible proximal portion can, individually or in combination, provide a more stable system for delivering the implant. However, flexible structures may be prone to deformation or expansion during operation. The stretch-resistant fibers 16 and / or detachable features 18, individually or in combination, can support the coil 12 and suppress deformation and expansion of the coil 12 according to the principles described herein. An object of the present invention is to provide an implant 10 configured to interlock with a delivery tube 300 having a highly flexible proximal portion and / or a highly flexible distal portion.

[0054] Figure 14A is an example of an implant 10 and a delivery tube 300 configured to deliver and position the implant 10. Figures 14B–14D illustrate a series of steps for releasing the exemplary embolization implant 10 from the delivery tube 300. A portion of the delivery tube 300 has been cut off for illustrative purposes.

[0055] Figure 14A illustrates an engagement system including a pull wire 140 and a loop wire 400 locked within the detachment feature 18 of the implant 12. The delivery tube 300 may include a compressible portion 306 that can be compressed. The loop wire 400 may have an opening 405 at its distal end 404, the opening 405 can be placed through an opening 22a of the detachment feature 18. Once the pull wire 140 is inserted through the opening 405, the implant 12 is secured therein.

[0056] The detachment feature 18 may include a bridge 28 positioned distal to the loop wire opening 405 and positioned to support the distal portion of the pull wire 140, distal to the location where the loop wire opening 405 is supported by the pull wire 140. In this configuration, the bridge 28 can support the distal portion of the pull wire 140 so that when the loop wire 400 strongly pulls the pull wire 140 at the loop opening 405, the bridge 28 can suppress deformation of the distal portion of the pull wire 140. A proximal tab 38 may be positioned to support a portion of the pull wire 140, proximal to the location where the loop wire opening 405 is supported by the pull wire 140. The combination of the bridge 28 and the proximal tab 38 can suppress deformation of the pull wire 140 due to the force applied by the loop wire 400. The delivery tube 300 can be detachably attached to the implant 10, as illustrated in Figure 14A, while delivering the implant 10 through the vascular structure and while the implant 10 is positioned at the treatment site. The bridge 28 can reduce the possibility of premature release of the implant 10 due to bending of the pull wire 140 caused by force from the loop wire 400.

[0057] The bridge 28 may separate the proximal opening 22a and the distal opening 24a in a double-opening implant as illustrated. It is also intended that a single-opening implant may be adapted to include a structure that can function to support the distal portion of the pull wire 140, similar to that described with respect to the illustrated bridge 28. Thus, alternative bridge structures are intended to be within the scope of the present invention.

[0058] Figure 14B illustrates the pull wire 140 being retracted proximal to initiate the release sequence of the implant 10. Figure 14C illustrates the moment when the pull wire 140 exits the opening 405 and is detached from the loop wire 400. The distal end 404 of the loop wire 400 detaches and exits the locking portion 18. As can be seen from the figure, there is nothing holding the implant 10 to the delivery tube 300 at this point. Figure 14D shows the end of the release sequence. Here, the compressible portion 306 expands / returns to its original shape and "snaps" forward. The distal end 304 of the delivery tube 300 imparts an elastic force E to the medical device 10, "pushing" it away, ensuring clean separation and delivery of the medical device 10.

[0059] Figure 15 is a cross-sectional view of the proximal section of an alternatively constructed implant 10c having elements described in relation to Figure 1A, which has similar reference numerals indicating similar elements. Compared to the implant 10a illustrated in Figure 1A, the implant 10c illustrated in Figure 15 may have an alternative detachment feature 18c. The detachment feature 18c illustrated in Figure 18c may have a portion having a width D2 sized to fit into the lumen 13 of an embolization coil 12 having an inner diameter D1. The width D2 of the detachment feature 18c can be greater than the inner diameter D1 of the coil lumen 13 so that when the detachment feature 18c is positioned in the lumen 13, the proximal portion of the lumen 13 expands to a diameter D2 to accommodate the width D2 of the detachment feature 18c. When configured in this way, the expanding portion of the coil 12 can provide compressive force to the section of the detachment feature having a width D2 to help secure the detachment feature 18c to the coil 12.

[0060] Compared to the implant 10a illustrated in Figure 1A, the bridge 28c may extend proximal to the proximal end of the embolic coil 12. With this configuration, in some configurations, it is not necessary to insert the pull wire 140 into the lumen 13 of the embolic coil 12 supported by the bridge 28c. By limiting the length of the pull wire 140 inserted into the embolic coil 12, the flexibility of the proximal section of the embolic coil can be increased.

[0061] The implant 10c illustrated in Figure 15 can be constructed according to the principles illustrated in Figures 2A and 2B to 7. The implant 10c illustrated in Figure 15 can be used according to the principles illustrated in Figures 9 and 11 to 14D.

[0062] Figure 16 is a diagram of another exemplary detachment feature 18d. Various dimensions of the detachment feature 18d are shown in Figure 16. These dimensions can be selected based on design criteria, and as a result, the detachment feature 18d can be customized to a given implant. Figures 17A to 17H are diagrams of exemplary detachment features having a general structure similar to the detachment feature 18d shown in Figure 16, with various dimensions shown in Figure 16 adjusted to customize the detachment feature 18d. This detachment feature is positioned with respect to the longitudinal axis LL, the distal direction 54, and the proximal direction 52.

[0063] The proximal portion 32 of the detachment feature portion 18d has a first width W1 near the proximal end of the detachment feature portion 18d, which is sized to fit within the notch 310 of the delivery tube 300. Preferably, the first width W1 is approximately equal in size to the outer diameter of the distal end 304 of the delivery tube 300.

[0064] The distal portion 34 of the detachment feature portion 18d has a second width W2 and a third width W3, similar to those disclosed in relation to Figures 2A and 15.

[0065] The proximal portion 32 of the detachment feature portion 18d has a fourth width W4 near the engagement surfaces 36a and 36b of the detachment feature portion 18d. The fourth width W4 is preferably approximately equal in size to the outer diameter of the embolus coil 12.

[0066] The distal opening 18d of the detachable feature portion 24d has a fifth width W5. The fifth width W5 is wide enough to allow the stretch-resistant fiber 16 to be inserted, and narrow enough so that sufficient material of the distal portion 34 of the detachable feature portion 18d can maintain structural integrity.

[0067] The proximal extension 38 of the detachment feature portion 18d has a sixth width W6. The sixth width W6 is preferably approximately equal to and smaller than the diameter of the lumen of the delivery tube 300 at the distal end 304 of the delivery tube 300.

[0068] The proximal portion 32 of the detachment feature portion 18d has a third length L3. The third length L3 is preferably approximately equal to and greater than the depth of the notch 310 of the delivery tube 300.

[0069] The distal portion 34 of the detachable feature portion 18d has a fourth length L4. The fourth length L4 is preferably a size that is long enough to facilitate the assembly of the implant 10, maintain the structural integrity of the implant 10, and provide sufficient material for the distal opening 24d and the bridge 28d. The fourth length L4 is preferably short enough to allow flexibility of the proximal portion of the implant 10.

[0070] The distal opening 18d of the detachable feature portion 24d has a fifth length L5. The fifth length L5 is long enough to insert the stretch-resistant fiber 16 and short enough to make the fourth length L4 sufficiently short.

[0071] The detachment feature portion 18d may include a longitudinal offset between the engaging surfaces 36a and 36b. The longitudinal offset (sixth length L6) is preferably approximately equal to half the diameter D3 (Figure 15) of the wire that is wound to form the embolus coil 12.

[0072] The distal opening 24d may include a non-traumatic surface 25 that comes into contact with the tensile fibers when the implant 10 is assembled. The non-traumatic surface 25 may be shaped to reduce the possibility of the tensile fibers 16 being abraded by the detachment feature 18d. Similarly, the proximal opening 22d may include a non-traumatic surface 23 that is shaped to reduce the possibility of the loop wire 400 being abraded by the detachment feature 18d.

[0073] Figure 18 shows the proximal portion 32d of the exemplary detachment feature 18d shown in Figure 16. The proximal opening 22d is approximately a pentagon with a base having a non-traumatic surface 23 and four distally extending sides 30 of approximately equal length. The corners of this polygon are rounded. The corner 27 adjacent to the non-traumatic surface 23 (polygon base) can be deepened to encourage the loop wire 400 to rest on the deepened corner 27.

[0074] As used herein, the terms “about” or “approximately” for any number or range of numbers indicate a suitable dimensional tolerance that enables a part or set of components to function in accordance with its intended purpose as described herein. More specifically, “about” or “approximately” may refer to a range of values ​​within ±20% of the listed values, for example, “about 90%” may refer to a range of values ​​between 71% and 99%.

[0075] The descriptions contained herein are examples of embodiments of the present invention and do not limit the scope of the invention in any way. As described herein, the present invention envisions many variations and modifications of implants, including alternative materials, alternative geometric shapes of component parts, alternative positioning of component parts relative to each other, and methods for fabricating and using implants. These modifications will be obvious to those skilled in the art to whom the present invention relates and are intended to be within the scope of the following claims.

[0076] [Implementation Method] (1) Embolization implant, Embolization coils including coiled wires, A detachment feature portion attached to the embolic coil and adjacent to the proximal end of the embolic coil, comprising a first engagement surface and a second engagement surface offset from each other in the longitudinal direction by a length approximately equal to half the diameter of the coiled wire, An embolic implant comprising: a stretch-resistant fiber that engages with the detachable portion, extends through the lumen of the embolic coil, and is adjacent to the distal end of the embolic coil attached to the embolic coil. (2) The embolic implant according to Embodiment 1, wherein the stretch-resistant fibers are effective in limiting the separation of the windings of the embolic coil when the embolic coil is reshaped. (3) The detachable feature portion has a first opening through it and a second opening separated from the first opening, The stretch-resistant fiber passes through the first opening, At least a portion of the first opening is positioned within the lumen of the embolic coil, The embolic implant according to Embodiment 1, wherein at least a portion of the second opening is positioned proximal to the proximal end of the embolic coil. (4) The embolic implant according to Embodiment 3, wherein the second opening has a non-traumatic surface at the distal end of the second opening. (5) The embolic implant according to Embodiment 3, wherein the first opening has a non-traumatic surface perpendicular to the longitudinal axis of the detachment feature portion.

[0077] (6) The embolic implant according to Embodiment 3, wherein the second opening has an approximately polygonal shape with four sides of approximately equal length and a fifth side longer than the four sides, and the fifth side is perpendicular to the longitudinal axis of the detachment feature portion. (7) The embolic implant according to Embodiment 6, wherein the polygonal shape has two corners at both ends of the fifth side, each extending proximal to the fifth side. (8) The lumen of the embolic coil has an inner diameter, The detachable feature portion comprises a proximal portion located proximal to the lumen and a distal portion located within the lumen. The proximal portion has a first width that is larger than the inner diameter of the lumen, The embolic implant according to Embodiment 1, wherein the distal portion has a second width that is substantially equal to the inner diameter of the lumen. (9) A system, An implant comprising an embolization coil and a detachment feature, wherein the detachment feature comprises a distal portion extending into the lumen of the embolization coil, a proximal portion extending proximal to the proximal end of the embolization coil, a first engagement surface attached to the proximal end of the embolization coil, and a second engagement surface attached to the proximal end of the embolization coil, wherein the first engagement surface and the second engagement surface are offset from each other longitudinally by a length approximately equal to half the diameter of the coiled wire of the embolization coil, Pull wire and A system comprising: a delivery tube attached to the detachment feature portion and configured to detach from the implant when the pull wire moves in the proximal direction. (10) The detachable feature portion further has a distal opening that penetrates the distal portion, The system according to embodiment 9, wherein the implant further comprises a stretch-resistant fiber that extends through the distal opening and is attached to the embolic coil in proximity to the distal end of the embolic coil.

[0078] (11) The system according to embodiment 10, wherein the distal opening comprises a non-traumatic surface placed alongside the stretch-resistant fibers. (12) The system according to embodiment 10, wherein the stretch-resistant fibers are effective in limiting the separation of the windings of the embolic coil when the embolic coil is reshaped. (13) Further comprising a loop wire attached to the delivery tube, The detachment feature portion further comprises a proximal opening that penetrates the proximal portion, The system according to embodiment 9, wherein the loop wire extends through the proximal opening around the pull wire so that the delivery tube is attached to the detachment feature. (14) The system according to embodiment 13, wherein the proximal opening comprises a non-traumatic surface positioned alongside the loop wire. (15) The non-traumatic surface has two deepened corners that extend proximal to the side surface of the non-traumatic opening perpendicular to the longitudinal axis of the detachment feature portion, The system according to embodiment 14, wherein the loop wire is positioned within each of the two deepened corners.

[0079] (16) The system according to embodiment 13, wherein the proximal opening is shaped to approximate a pentagon. (17) The detachable feature portion further comprises a distal opening that penetrates the distal portion, The detachment feature portion further comprises a proximal opening that penetrates the proximal portion, The detachment feature further comprises a bridge that separates the distal opening and the proximal opening. The system according to embodiment 9, wherein the bridge supports a portion of the pull wire. (18) The system according to embodiment 9, wherein the proximal portion of the detachment feature has a width approximately equal to the outer diameter of the delivery tube. (19) The system according to embodiment 9, wherein the proximal portion of the detachment feature has a width approximately equal to the outer diameter of the embolic coil. (20) The system according to embodiment 9, wherein the proximal portion comprises a proximal extension having a width smaller than the diameter of the lumen of the delivery tube at the distal end of the delivery tube and approximately equal to the diameter.

Claims

1. It is an embolization implant, Embolization coils including coiled wires, A detachment feature portion attached to the embolization coil and located near the proximal end of the embolization coil, comprising a first engagement surface and a second engagement surface offset from each other in the longitudinal direction by a length approximately equal to half the diameter of the coiled wire, The system comprises stretch-resistant fibers that engage with the detachable portion, extend through the lumen of the embolic coil, and are adjacent to the distal end of the embolic coil attached to the embolic coil, The detachable feature portion has a first opening that penetrates it and a second opening separated from the first opening. The stretch-resistant fiber passes through the first opening, At least a portion of the first opening is positioned within the lumen of the embolic coil, At least a portion of the second opening is positioned proximal to the proximal end of the embolic coil, The second opening has an approximately polygonal shape with four sides of approximately equal length and a fifth side that is longer than the four sides, and the fifth side is perpendicular to the longitudinal axis of the detachment feature portion. Embolization implant.

2. The embolic implant according to claim 1, wherein the stretch-resistant fibers are effective in limiting the separation of the windings of the embolic coil when the embolic coil is reshaped.

3. The embolic implant according to claim 1, wherein the polygonal shape has two corners at both ends of the fifth side, each extending proximal to the fifth side.

4. The lumen of the embolic coil has an inner diameter, The detachable feature portion comprises a proximal portion located proximal to the lumen and a distal portion located within the lumen. The proximal portion has a first width that is larger than the inner diameter of the lumen, The embolic implant according to claim 1, wherein the distal portion has a second width that is substantially equal to the inner diameter of the lumen.

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