Connecting elements and stretch-resistant fibers proximal to the embolization coil

Abstract

The present invention, entitled "Connecting Element and Stretch-Resistant Fiber Proximal to an Embolic Coil," provides an embolic coil implant having a stretch-resistant fiber extending therethrough and a dual-function engagement feature at its proximal end. The stretch-resistant fiber effectively limits separation of the embolic coil windings. The engagement feature provides an attachment for securing the embolic coil to the engagement system of a delivery tube and for securing the stretch-resistant fiber at the proximal end of the embolic coil.

Description

Technical Field

[0001] The present invention relates generally to implantable medical devices and, more particularly, to engagement features for mechanically and releasably securing an implantable medical device to a delivery system. Background Art

[0002] Endovascular treatment of an aneurysm can be performed by delivering a therapeutic device to the aneurysm to fill the aneurysm sac with an embolic material and / or occlude the neck of the aneurysm to inhibit blood flow into the aneurysm. When filling the aneurysm sac, the embolic material can promote blood clotting, resulting in a thrombus within the aneurysm. When treating the aneurysm neck without substantially filling the aneurysm sac, blood flow into the aneurysm neck can be inhibited, causing venous stasis in the aneurysm and promoting the natural formation of a thrombus within the aneurysm.

[0003] In some current treatments, multiple embolic coils are used to fill the aneurysm sac or treat the inlet of the aneurysm neck. A common challenge in embolic coil treatment is that implanted coils and implanted portions of partially implanted coils can become tangled and difficult to reposition. In some cases, the physician may be unable to retract the partially implanted coil and may be forced to position the coil in a non-ideal position. Improper positioning of the embolic coil at the aneurysm neck can have the adverse effect of obstructing blood flow in adjacent vessels, particularly if the inlet and / or sac are overfilled. If a portion of the non-ideal implanted coil becomes dislodged, it can enter an adjacent vessel and promote clot formation, which can ultimately lead to an obstruction that is tethered to the aneurysm and therefore extremely difficult to treat. Conversely, if the inlet and / or sac are not adequately filled, blood flow can continue to enter the aneurysm.

[0004] In some current treatments, an embolic coil is attached to a tubular delivery member and delivered to the aneurysm via a delivery catheter. During delivery, the embolic coil can be engaged to an implant engagement / deployment system (equivalently referred to herein as an "engagement system" or "deployment system") of the delivery member. Once the embolic coil is in place, the deployment system can release the coil, the coil can remain implanted, and the delivery member can be retracted. Some treatments utilize a mechanical engagement / deployment system that can be actuated by a physician by pulling on one or more wires or other elongated members, collectively referred to herein as "pull wires," to release the implant.

[0005] Some challenges associated with delivering and deploying embolic coils using a delivery member with a mechanical engagement system include premature release of the coil and movement of the delivery member due to push-back from densely packed treatment sites.

[0006] Therefore, there is a need for improved methods, devices, and systems that facilitate the implantation of embolic coils and other implants that face similar challenges. Summary of the Invention

[0007] The object of the present invention is to provide systems, devices and methods that meet the above needs. In some examples presented herein, stretch-resistant fibers positioned within the lumen of the coil are used to reduce or prevent the separation of the coil windings within the embolic coil. In some cases, reducing or preventing the separation of the coil windings can prevent the implanted portion of a partially implanted coil from becoming entangled with the implanted coil, thereby making it easier to reposition and / or withdraw some or all of the coil. In some examples presented herein, during the delivery of the embolic coil, the distal end of the puller wire is supported by an engagement / disengagement feature (equivalently referred to herein as an "engagement feature," "disengagement feature," or "key") attached to the proximal end of the embolic coil. In some cases, the support provided by the key can reduce the possibility of premature release of the embolic coil. In some examples presented herein, the embolic implant can have a highly flexible proximal portion. The flexibility of the embolic implant can, in some cases, reduce the force on the delivery member caused by pushing back from a densely packed treatment site, thereby reducing the movement of the delivery member caused by pushing back.

[0008] To meet some or all of these needs, an implant is provided that includes an embolic coil, a stretch-resistant fiber extending through the coil, and a breakaway feature / key at the proximal end of the coil. The stretch-resistant fiber effectively limits separation of the embolic coil windings. The key provides an attachment for securing the embolic coil to a coupling system of a delivery tube and for securing the stretch-resistant fiber at the proximal end of the embolic coil.

[0009] An exemplary method 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. Some or all of an implant comprising an embolic coil and a stretch-resistant fiber may be positioned within the aneurysm. A portion of the embolic coil may be retracted from the aneurysm. When the portion of the stretch-resistant fiber is retracted from the aneurysm, the stretch-resistant fiber may inhibit elongation of the portion. The embolic coil may be bendable, and the stretch-resistant fiber may limit the spacing of the windings of the embolic coil at the bend.

[0010] The stretch-resistant fiber can be positioned to extend within the lumen of the embolic coil.The stretch-resistant fiber can be subjected to tension along a majority of its length.

[0011] The implant can be secured to the delivery system with a key coupled to the stretch-resistant fiber. To secure the implant to the delivery system, the loop of the delivery system can be positioned to pass through the key, and the pull wire can be positioned to pass through an opening in the loop. When the implant is secured to the delivery system, the pull wire can be supported by the key in both a proximal direction from the loop and a distal direction from the loop.

[0012] During delivery and / or positioning of the implant, the bond may be visualized radiographically.

[0013] The key can be released from the delivery system to release the implant from the delivery system. When the implant is released, the key can remain attached to the implant.

[0014] An exemplary embolic implant may include an embolic coil, a breakaway feature, and a stretch-resistant fiber. The breakaway feature may be attached to the embolic coil at its proximal end. The stretch-resistant fiber may be coupled to the breakaway feature, extend through the lumen of the embolic coil, and be attached to the embolic coil at its distal end. Thus configured, the stretch-resistant fiber may effectively limit separation of the windings of the embolic coil during reshaping of the embolic coil.

[0015] The stretch-resistant fiber may be a suture. The stretch-resistant fiber may be inelastic.

[0016] The detachment feature may be radiopaque.

[0017] The breakaway feature may have an opening through which the stretch-resistant fiber passes. The opening may extend proximally from the proximal end of the embolic coil.

[0018] The breakaway feature may have a single opening sized to receive the loop of the mechanical delivery system and through which the stretch-resistant fiber passes.

[0019] Alternatively, the breakaway feature may have two separate openings: a first opening through which the stretch-resistant fiber passes, and a second opening sized to receive a loop of the mechanical delivery system. The first opening may be positioned at least partially within the lumen of the embolic coil. The second opening may be positioned at least partially proximally from the proximal end of the embolic coil.

[0020] Exemplary system can comprise exemplary embolic implant and mechanical delivery system, and this exemplary embolic implant has the breakaway feature portion with two separate openings, and this mechanical delivery system comprises loop line and pull line.Stretch-resistant fiber can pass through one of two openings, and loop line can pass through the other of two openings.Pull line can be positioned to pass through the opening in loop line, thereby utilize loop line to fix implant to mechanical delivery system.Breakaway feature portion can also comprise the bridge piece that is positioned between two openings of breakaway feature portion, and this bridge piece can support the part of pull line in the distal direction of the ring opening in loop line.

[0021] The detachment feature may have a proximal portion disposed proximal to the lumen of the embolic coil and a distal portion disposed within the lumen. The proximal portion may measure a width greater than the inner diameter of the lumen of the embolic coil, and the distal portion may measure a width approximately equal to the inner diameter of the lumen of the embolic coil.

[0022] An exemplary method for constructing and designing an embolic implant, such as the exemplary implant described herein, may include one or more of the following steps, presented in no particular order, and the method may include additional steps not included herein. The breakaway feature may be cut from a flat sheet of material. One or more openings may be cut from the breakaway feature. A stretch-resistant fiber may be passed through the openings in the breakaway feature. The stretch-resistant fiber may extend through the lumen of the embolic coil. The breakaway feature may be attached at one end of the embolic coil. The stretch-resistant fiber may be attached at the other end of the embolic coil. Tension may be provided along the stretch-resistant fiber between the breakaway feature and the second end of the embolic coil.

[0023] A portion of the mechanical deployment system can extend through the opening in the breakaway feature to couple the breakaway feature to the delivery tube. The mechanical deployment system can extend through the same opening through which the stretch-resistant fibers are threaded, or through an opening in the breakaway feature that is separate from the opening through which the stretch-resistant fibers are threaded.

[0024] The breakaway feature may be cut from a flat sheet of radiopaque material.

[0025] The distal portion of the detachment feature can be inserted into the lumen of the embolic coil, and the proximal portion of the detachment feature can extend proximally from the proximal end of the embolic coil. The embolic 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 embolic coil, and the distal portion of the detachment feature is approximately equal to the inner diameter of the lumen of the embolic coil.

[0026] To attach the breakaway feature to the embolic coil, the breakaway feature may be welded to the embolic coil. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The above and further aspects of the present invention will be further discussed with reference to the following description in conjunction with the accompanying drawings,

[0028] In these drawings, similar numbers indicate similar structural elements and features in various figures. The drawings are not necessarily drawn to scale, with emphasis instead being placed on illustrating the principles of the invention. The drawings depict one or more specific implementations of the device of the invention by way of example only and not limitation.

[0029] Figure 1A and Figure 1B is a diagrammatic representation of an embolic implant according to aspects of the present invention;

[0030] Figure 2A and Figure 2B is an illustration of breakaway features each having a stretch-resistant fiber passing therethrough according to aspects of the present invention;

[0031] Figure 3 is an illustration of a stretch-resistant fiber inserted into the lumen of an embolic coil according to aspects of the present invention;

[0032] Figure 4 is an illustration of a stretch-resistant fiber exiting the lumen of an embolic coil according to aspects of the present invention;

[0033] Figure 5A and Figure 5B is an illustration of a breakaway feature inserted into a lumen of an embolic coil according to aspects of the present invention;

[0034] Figure 6A and Figure 6B is an illustration of a breakaway feature attached to an embolic coil according to aspects of the present invention;

[0035] Figure 7 is an illustration of a stretch-resistant fiber attached to the end of an embolic coil according to aspects of the present invention;

[0036] Figures 8A to 8C shows a time series in which the embolic coil stretches due to non-optimal stretch-resistant fiber placement;

[0037] Figure 9 is an illustration of an embolic coil positioned within an aneurysm according to aspects of the present invention;

[0038] Figure 10A is a diagram of an embolic coil becoming tangled, and

[0039] Figure 10B is an illustration of a tangled coil becoming elongated, which serves as an illustration of the problem of the prior art;

[0040] Figure 11 is an illustration of a stretch-resistant fiber that inhibits entanglement and elongation of an embolic coil according to aspects of the present invention;

[0041] Figure 12 A flowchart outlining method steps that may be performed as part of aneurysm treatment according to aspects of the present invention;

[0042] Figure 13 is an illustration of an embolic implant secured to a delivery tube according to aspects of the present invention;

[0043] 14A to 14D shows a series of steps for releasing an embolic implant from a delivery tube according to aspects of the present invention; and

[0044] Figure 15 is an illustration of an end portion of an embolic implant including a breakaway feature that expands the inner diameter of an embolic coil according to aspects of the present invention. DETAILED DESCRIPTION

[0045] It is an object of the present invention to achieve more precise and repeatable implant detachment. More specifically, it is an object of the present invention to facilitate the implantation of embolic coils and other implants that face challenges such as partially implanted implants becoming difficult to reposition, delivery systems becoming displaced due to push-back during implantation, and / or implants releasing prematurely. To meet some or all of these needs, an exemplary implant may include: stretch-resistant fibers to limit stretching and other deformation of the embolic portion of the implant (e.g., an embolic coil); and a detachment feature to which the stretch-resistant fibers can be secured and to which the delivery system can be removably attached.

[0046] To facilitate repositioning of the implant, the stretch-resistant fiber may extend through the embolic coil and limit the separation of the coil windings when the coil is bent and pulled. By limiting the separation of the windings, the embolic coil is less likely to become tangled when partially implanted and is less likely to be stretched or otherwise deformed when retracted when partially implanted. Thus, the embolic coil can be more easily repositioned. In some examples, the breakaway feature may include two separate openings, one opening for securing the stretch-resistant fiber and the other opening for engaging the engagement system. The dual-opening breakaway feature can reduce potential manufacturing challenges to provide reliable positioning of the stretch-resistant fiber and, therefore, more reliably provide an implant that can be more easily repositioned.

[0047] To reduce the effects of push-back during implantation, a break-away feature can be sized and attached to the embolic coil to provide an embolic coil implant having a highly flexible proximal segment. The embolic coil implant having a highly flexible proximal segment can reduce push-back forces on the delivery tube, thereby mitigating the effects of delivery tube deviation. Additionally or alternatively, the break-away feature can be sized to mate with a delivery tube having a highly flexible distal segment, and the highly flexible distal segment of the delivery tube can mitigate the effects of delivery tube deviation. When the embolic coil implant having a highly flexible proximal segment is mated with a delivery tube having a highly flexible distal portion, the combination of the flexible distal segment of the delivery tube and the flexible proximal segment of the implant can further mitigate the effects of delivery tube deviation.

[0048] To reduce the risk of premature deployment, the detachment feature may include a bridge for supporting the puller wire. The detachment feature can be removably attached to a mechanical engagement / deployment system on the delivery tube. The detachment feature may include an opening through which the loop wires of the mechanical engagement system can pass. In some examples, the detachment feature may also include a bridge positioned distal to the opening, upon which a distal portion of the puller wire may rest. The bridge may inhibit deformation of the puller wire due to engagement with the loop wires, and thus may reduce the likelihood of premature release of the implant due to bending of the puller wire.

[0049] Figure 1A1 is an illustration of an implant 10a comprising an embolic coil 12 having a lumen 13 therethrough, a detachment feature 18a, and a stretch-resistant fiber 16. For illustrative purposes, portions of the coil 12 and weldment 42 are shown in cross-section. The detachment feature 18a may be partially positioned within the lumen 13 of the coil 12 and may extend beyond the coil 12. The detachment 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 a loop wire or other engagement mechanism of a mechanical implant engagement system. The detachment feature 18a may include a bridge 28a located between the distal opening 24a and the proximal opening 22a. The detachment feature 18a may include a proximal protrusion 38 sized to fit within the lumen of a delivery tube. The stretch-resistant fiber 16 may be secured to the end of the embolic coil 12 opposite the end to which the breakaway feature 18a is attached using a weld 44 or other suitable attachment.

[0050] As the breakaway feature 18a extends further within the lumen 13 of the embolic coil 12, the breakaway feature can be tapered to allow the embolic coil 12 additional flexibility where the embolic coil 12 surrounds the tapered region. The breakaway feature 18a can also have a substantially flat profile, providing even greater flexibility in directions into and out of the image plane.

[0051] The breakaway feature 18a can be fully secured to the coil 12 using the attachment 42 without fusing any of the windings of the coil 12 (as shown) or by fusing a small number of windings (e.g., 5 or fewer). Attachment 42 of the coil 12 can be implemented with significantly fewer fused coil windings compared to known solutions in which typically ten or more windings are welded together (in which control over the number of fused windings is limited). By reducing the number of fused windings, the proximal segment of the implant 10a can have increased flexibility compared to known designs that rely on fused windings from the proximal end of the embolic coil.

[0052] Figure 1B For the Figure 1A FIGURE 10b is an illustration of an alternative configuration of the components of the implant 10b, wherein like reference numerals indicate similar components. For illustrative purposes, portions of the coil 12 and weldment 42 are shown in cross-section. Figure 1A Compared to the implant 10a shown in FIG, the implant 10b can have an alternative breakaway feature 18b having a single opening 26b that provides an opening to which the mechanical engagement system can be engaged and through which the stretch-resistant fibers 16 can be looped. Figure 1B The illustrated breakaway feature 18b also does not include Figure 1A The extended tapered area of ​​the breakaway feature 18a is shown. Figure 1B Compared with implant 10b, Figure 1A The tapered region of the breakaway feature 18a shown in FIG may provide a more flexible proximal section of the implant 10a, but by providing flexibility in directions into and out of the image plane due to being flat, Figure 1B The breakaway feature 18b shown in FIG. 4 may provide a more flexible proximal segment than known embolic coil implants and, due to the low profile attachment 42 , may provide greater flexibility than designs that rely on fused windings from the proximal end of the embolic coil.

[0053] Figure 2A and Figures 2B to 7 Show Figure 1A and Figure 1B A series of steps are shown for constructing implants 10a and 10b. Figure 2A and Figure 2B The stretch-resistant fiber 16 is shown passing through the breakaway features 18a, 18b. The breakaway features 18a, 18b can be laser cut from a flat sheet of material. The flat sheet of material is preferably a radiopaque material that can be welded or otherwise attached to the embolic coil 12.

[0054] Figure 2A A dual-opening breakaway feature 18a is shown having a proximal portion 32 sized to engage a mechanical engagement system and / or a delivery tube. The proximal portion 32 is shown as having a width W1. The dual-opening breakaway feature 18a may have a distal portion 34 sized to fit within the lumen 13 of an embolic coil. The distal portion 34 may have a wider section having a width W2 that is approximately the same as the inner diameter of the embolic coil 12 and a tapered section having a width W3 that is significantly narrower than the inner diameter of the embolic coil 12. The breakaway feature 18a may have a proximal protrusion 38 that is narrower than the proximal portion 32 and sized to fit within the lumen of a delivery tube.

[0055] Figure 2B A single-opening breakaway feature 18b is shown having a proximal portion 32 that is sized to engage a mechanical engagement system and / or a delivery tube. Proximal portion 32 is shown having a width W1. Single-opening breakaway feature 18b may have a distal portion 34b that is narrower than proximal portion 32 and sized to fit within lumen 13 of coil 12. Single-opening breakaway feature 18b may have a proximal protrusion 38 that is narrower than proximal portion 32 and sized to fit within the lumen of a delivery tube.

[0056] After forming the breakaway features 18a, 18b, the stretch-resistant fiber 16 may be passed through the distal opening 24a of the dual-opening breakaway feature 18a or the single opening 26b of the single-opening breakaway feature 18b.

[0057] Figure 3 FIG. 1 is an illustration of the free end of the stretch-resistant fiber 16 being inserted into the proximal end 15 of the embolic coil 12. Figure 3 In the steps shown, the stretch-resistant fiber 16 may be passed through a Figure 2A and Figure 2B Breakaway features 10a, 10b are shown.

[0058] Figure 4 is an illustration of the free end of the stretch-resistant fiber 16 exiting the lumen 13 of the embolic coil 12 at the distal end 14 of the embolic coil 12 .

[0059] Figure 5A and Figure 5B 1 is an illustration of the breakaway features 18a, 18b inserted into the lumen 13 of the embolic coil 12. After leaving the distal end 14 of the embolic coil 12, the free end of the stretch-resistant fiber 16 may be removed as shown in FIG. Figure 4 As shown by the arrow in FIG, the embolic coil 12 is further pulled to move the detachment features 18a, 18b into the lumen 13 of the embolic coil 12 at the proximal end 15 of the embolic coil 12, as shown in FIG. Figure 5A and Figure 5B Before the detachment features 18a, 18b enter the lumen 13 of the embolic coil 12, the embolic coil may have Figure 5A The inner diameter D shown. The proximal portion 32 of the breakaway features 18a, 18b can be sized to have a width approximately equal to the inner diameter D over at least a portion of the distal portion 34 for a snug fit. Alternatively or additionally, at least a portion of the distal portion 34 can 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 can have a width less than the diameter D to allow for greater flexibility of the coil 12 near the proximal end 15 of the coil 12.

[0060] Figure 6A and Figure 6B FIG. 1 is an illustration of the breakaway features 18a, 18b with the distal portion 34 fully inserted into the lumen 13 of the embolic coil 12 and the breakaway features 18a, 18b attached to the embolic coil 12 using welds 42 or other attachments. Figure 6A and Figure 6B In both, the breakaway features 18 a , 18 b are shown as having a distal portion 34 having a width approximately equal to the inner diameter D of the lumen 13 of the embolic coil 12 over at least a portion of the length of the distal portion 34 .

[0061] Figure 7 FIG is a diagram of a stretch-resistant fiber 16 attached to the distal end of an embolic coil 12. Figure 6A and Figure 6BAfter attaching or at least positioning the detachment features 18a, 18b as shown, the stretch-resistant fibers 16 can be tensioned to reduce slack in the fibers 16 and / or create tension in the fibers 16, and the fibers 16 can be secured using welds 44 or other attachment features. After attaching the fibers 16, the fibers can be substantially stretch-resistant to resist significant elongation due to forces applied to the embolic coil 12 during preparation for treatment, during delivery of the implants 10a, 10b, during positioning of the implants at the treatment site, during retraction of the implants, and during deployment of the implants. In other words, the stretch-resistant fibers 16 can effectively limit elongation of the embolic coil 12 as it is retracted from the aneurysm, and can effectively limit separation of the windings within the embolic coil 12 as it is bent.

[0062] Figures 8A to 8C A time series is shown in which the embolic coil 12 is allowed to stretch due to the placement of non-optimal stretch-resistant fibers 16 . Figure 8A The non-optimal arrangement of fibers 16 within a single opening breakaway feature 18b is shown. The fibers 16 may become looped over the non-optimal section of the breakaway feature 18b such that Figure 8B The movement of the fibers 16 shown may result in the fibers 16 being dislodged from non-optimal positions and, as shown, Figure 8C As shown, the embolic coil 12 may be allowed to stretch at least until the fibers 16 reengage the breakaway features 18a. Figure 7 During the attachment steps shown, the fibers 16 are prevented from being positioned in areas such as Figure 8A If, after manufacture is complete, the fiber 16 is moved from Figure 8B If the implant 10B is displaced from the optimal position shown, the embolic coil 12 may be displaced as shown. Figure 8C shown elongated or otherwise deformed.

[0063] The advantage of the dual opening disengagement feature 18a is that Figure 1A During manufacture of the illustrated implant 10a, the stretch-resistant fibers 16 are less likely to become looped over the non-optimal section of the breakaway feature 18a.

[0064] Figure 9 2 is an illustration of one or more embolic implants 10 delivered via a delivery catheter 200 and positioned within an aneurysm A on a blood vessel BV. The implants can be looped and bent within the aneurysm sac to form a thrombus mass. The implants can be looped onto themselves and / or adjacent to other implants. As aneurysm A becomes increasingly dense, overlapping portions of the implants 10 can be compressed into one another.

[0065] Figure 10A1 illustrates an embolic coil 12 without the stretch-resistant fibers 16. The embolic coils 12 become tangled as the overlapping portions of the coils press into each other. This tangling can make it difficult or impossible to reposition any of the coils 12, a known problem with some current embolic coil implants. Figure 10B A portion of the embolic coil 12 is shown as it becomes elongated to a length L2 due to the force F, which is longer than Figure 10A The length L1 of the segment is shown. Figure 10B The following scenario is shown where a physician may attempt to retract a tangled, partially implanted embolic coil and may not only be unable to retract the coil, but also exacerbate an already challenging treatment by now having to position a deformed, elongated coil. Tangling may become more likely when the windings of the embolic coil separate, for example due to bending, or when the coils are pressed more tightly together due to dense packing.

[0066] Figure 11 1 is an illustration of an exemplary embolic coil 12, each having a stretch-resistant fiber 16 that is inhibited from tangling and elongating, according to aspects of the present invention. Each coil 12 is shown having a curved portion 20. The stretch-resistant fiber 16 can be offset within the lumen 13 of each coil to allow the coil 12 to flex and bend as needed when implanted. The fiber 16 can have sufficient tension to limit the amount of spacing between the windings in the curved portion 20. The spacing of the windings can be limited to prevent the windings of two adjacent coils 12 from being tangled or elongated. Figure 10A Tangle shown. Figure 11 Also shown is a force F applied to a portion 40 of the coil 12 and the portion 40 being inhibited from elongating due to tension in the stretch-resistant fibers 16 . Figure 11 A situation is shown in which a physician can successfully retract a partially implanted embolic coil 12 having stretch-resistant fibers 16 passing therethrough.

[0067] Figure 12 To illustrate a flow chart of method 500, the method includes steps that can be performed as part of an aneurysm treatment using exemplary implants such as those described herein (10, 10a, 10b). In step 510, an implant having an embolic coil and stretch-resistant fibers can be positioned at least partially within the aneurysm sac. In step 520, a portion of the embolic coil can be bent. In step 530, the stretch-resistant fibers can inhibit winding separation within the bent portion of the embolic coil as the coil is bent. In step 540, some or all of the implanted portion of the implant can be retracted from the aneurysm. In step 550, the stretch-resistant fibers can inhibit elongation of the embolic coil as the implant is retracted.

[0068] Figure 13 For example, an embolic implant 10 secured to a delivery tube 300 such as Figure 1A and Figure 1B10a, 10b, or an implant otherwise described herein. Exemplary delivery tubes and engagement / deployment systems are described in U.S. Patent Application 2019 / 0192162 and U.S. Patent Application 15 / 964,857, each of which is incorporated herein by reference. The delivery tube 300 may include a recess 310 sized to receive the proximal portion 32 of the breakaway feature 18 of the implant 10. Similarly, the proximal portion 32 of the breakaway feature 18 may be sized to fit within the recess 310 of the delivery tube 300. Figure 13 A side view of the implant 10 is shown, highlighting the flat profile of the breakaway feature 18. Figure 1A and Figure 1B As described above, because the breakaway feature 18 is flat and / or because the breakaway feature 18 is fixed to the coil 12 without fusing the multiple coil windings, the implant 10 can have a highly flexible proximal section. The breakaway feature 18 can also be tapered to increase flexibility in directions into and out of the imaging plane. The breakaway feature 18 can also include a proximal protrusion 38 positioned within the lumen of the delivery tube 300.

[0069] During aneurysm occlusion treatment, it is known that the lack of flexibility in the proximal segment of an embolic implant and / or the 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 moved out of position when the implant is placed in the aneurysm. Therefore, a delivery tube having a more flexible distal portion and an implant having a more flexible proximal segment, alone or in combination, can provide a more stable system for delivering the implant. However, flexible structures can tend to deform or stretch when manipulated. According to the principles described herein, the stretch-resistant fibers 16 and / or the breakaway feature 18 can, alone or in combination, support the coil 12 and inhibit deformation and stretching of the coil 12. It is an object of the present invention to provide an implant 10 having a highly flexible proximal segment and / or being configured to cooperate with a delivery tube 300 having a highly flexible distal portion.

[0070] Figure 14A is an illustration of an implant 10 and a delivery tube 300 configured for delivering and positioning the implant 10 . 14B to 14D is an illustration of a series of steps for releasing an exemplary embolic implant 10 from a delivery tube 300. For illustrative purposes, a portion of the delivery tube 300 is cut away.

[0071] Figure 14AThe embodiment of the present invention shows an engagement system including a puller wire 140 and a loop wire 400 that are locked into 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 the distal end 404 of the loop wire 400, and the opening 405 may be placed through the opening 22a in the detachment feature 18. When the puller wire 140 is passed through the opening 405, the implant 12 is now secured.

[0072] The disengagement feature 18 may include a bridge 28 positioned distal to the loop opening 405 and positioned to support a distal portion of the pull wire 140 distal to the location where the loop opening 405 is supported by the pull wire 140. So configured, the bridge 28 may support the distal portion of the pull wire 140 so that when the loop 400 drags the pull wire 140 at the loop opening 405, the bridge 28 may inhibit deformation of the distal portion of the pull wire 140. The proximal tab 38 may be positioned to support a portion of the pull wire 140 proximal to the location where the pull wire 140 supports the loop opening 405. The combination of the bridge 28 and the proximal tab 38 may inhibit deformation of the pull wire 140 due to the force applied by the loop 400. Figure 14A As shown, during delivery of the implant 10 through the vasculature and when the implant 10 is positioned at the treatment site, the delivery tube 300 can be removably attached to the implant 10. The bridge 28 can reduce the likelihood of premature release of the implant 10 due to bending of the puller wire 140 caused by the force from the loop wire 400.

[0073] A bridge 28 can separate the proximal opening 22a and the distal opening 24a in a dual-opening implant, as shown. It is also contemplated that a single-opening implant can be adapted to include a structure that can be used to support the distal portion of the puller wire 140, similar to the structure described with respect to the illustrated bridge 28. Thus, alternative bridge structures are intended to be within the scope of the present invention.

[0074] Figure 14B Pull wire 140 is shown being pulled proximally to initiate the release sequence of implant 10 . Figure 14C The moment when the puller wire 140 exits the opening 405 and is pulled out of the loop 400 is shown. The distal end 404 of the loop 400 disengages and leaves the locking portion 18. As can be seen, there is now nothing holding the implant 10 to the delivery tube 300. Figure 14D The end of the release sequence is shown. Here, the compressible portion 306 has expanded / recovered to its original shape and "popped" forward. The distal end 304 of the delivery tube 300 applies a spring force E to the medical device 10 to "push it away," thereby ensuring complete detachment and delivery of the medical device 10.

[0075] Figure 15For the Figure 1A A cross-sectional view of a proximal segment of an implant 10c showing an alternative configuration of the elements described, wherein like reference numerals indicate like elements. Figure 1A Compared to the implant 10a shown, Figure 15 The illustrated implant 10c may have an alternative breakaway feature 18c. Figure 15 The illustrated breakaway feature 18c can have a portion having a width D2 sized to fit within the lumen 13 of an embolic coil 12 having an inner diameter D1. The width D2 of the breakaway feature 18c can be greater than the inner diameter D1 of the coil lumen 13, such that when the breakaway feature 18c is positioned within the lumen 13, the proximal portion of the lumen 13 expands to a diameter D2 to accommodate the width D2 of the breakaway feature 18c. Thus configured, the expanded portion of the coil 12 can provide a compressive force against the segment of the breakaway feature having width D2, thereby helping to secure the breakaway feature 18c to the coil 12.

[0076] and Figure 1A Compared to the implant 10a shown, the bridge 28c can extend proximally from the proximal end of the embolic coil 12. Thus configured, in some configurations, the puller wire 140 does not need to be inserted into the lumen 13 of the embolic coil 12 to be supported by the bridge 28c. Limiting the length of the puller wire 140 inserted into the embolic coil 12 can increase the flexibility of the proximal segment of the embolic coil.

[0077] Figure 15 The implant 10c shown may be configured according to Figure 2A and Figures 2B to 7 The principle shown is used to construct. Figure 15 The implant 10c shown may be configured according to Figure 9 as well as Figures 11 to 14D The principle shown is used.

[0078] As used herein, the term "about" or "approximately" for any numerical value or range indicates a suitable dimensional tolerance that allows the component or collection of elements to achieve its intended purpose as described herein. More specifically, "about" or "approximately" can refer to a range of ±20% of the value of the recited value, for example, "about 90%" can refer to a range of values ​​from 71% to 99%.

[0079] The description contained herein is an example of an embodiment of the present invention and is not intended to limit the scope of the present invention in any way. As described herein, the present invention contemplates many variations and modifications of implants and their manufacture and methods of use, including alternative materials, alternative geometric shapes of components, alternative positioning of components relative to each other, etc. It is apparent to those skilled in the art that the present invention should be included within the scope of the appended claims.

Claims

1. An embolic implant, comprising: an embolic coil comprising a lumen therethrough, a proximal end, and a distal end; a breakaway feature attached to the embolic coil proximate the proximal end of the embolic coil; as well as a stretch-resistant fiber coupled to the detachment feature, extending through the lumen of the embolic coil, and attached to the embolic coil proximate the distal end of the embolic coil, wherein the stretch-resistant fibers effectively limit separation of the windings of the embolic coil as the embolic coil reshapes; wherein the lumen of the embolic coil comprises a first inner diameter in a non-expanded portion of the lumen and a second inner diameter in an expanded portion of the lumen; wherein the breakaway feature includes a proximal portion disposed proximal to the cavity and a distal portion disposed within the cavity; wherein the proximal portion comprises a first width measuring greater than the first inner diameter of the lumen; and wherein the distal portion comprises a second width measuring greater than the first inner diameter of the lumen and approximately equal to the second inner diameter of the lumen.

2. The embolic implant according to claim 1, wherein The stretch-resistant fiber is a suture thread.

3. The embolic implant according to claim 1, wherein The stretch-resistant fibers are inelastic.

4. The embolic implant according to claim 1, wherein The detachment feature is radiopaque.

5. The embolic implant according to claim 1, in, The breakaway feature includes an opening therethrough, wherein the stretch-resistant fiber passes through the opening of the breakaway feature, wherein the opening extends proximally from the proximal end of the embolic coil, and wherein the opening is sized and positioned to receive a loop of a robotic delivery system.

6. The embolic implant according to claim 1, in, The breakaway feature includes a first opening therethrough and a second opening therethrough separate from the first opening, wherein the anti-tensile fiber passes through the first opening, wherein at least a portion of the first opening is positioned within the lumen of the embolic coil, and Wherein, at least a portion of the second opening is positioned proximal to the proximal end of the embolic coil.

7. A system comprising: The embolic implant according to claim 6; as well as a mechanical delivery system comprising a loop wire positioned through the second opening and a pull wire positioned through an opening in the loop wire, Wherein the breakaway feature further comprises a bridge separating the first opening and the second opening, and wherein the bridge supports a portion of the pull wire in a distal direction from the opening in the loop wire.

8. A method comprising: passing the stretch-resistant fiber through a first opening in the breakaway feature; extending the stretch-resistant fiber through the lumen of the embolic coil; attaching the breakaway feature to the first end of the embolic coil; attaching the stretch-resistant fiber to a second end of the embolic coil opposite the first end; as well as providing tension along the stretch-resistant fiber between the detachment feature and the second end of the embolic coil; wherein the lumen of the embolic coil comprises a first inner diameter in a non-expanded portion of the lumen and a second inner diameter in an expanded portion of the lumen; wherein the breakaway feature includes a proximal portion disposed proximal to the cavity and a distal portion disposed within the cavity; wherein the proximal portion comprises a first width measuring greater than the first inner diameter of the lumen; and wherein the distal portion comprises a second width measuring greater than the first inner diameter of the lumen and approximately equal to the second inner diameter of the lumen.

9. The method according to claim 8, further comprising: cutting the breakaway feature from the flat sheet of material; cutting the first opening in the breakaway feature; as well as A portion of a mechanical deployment system is extended through the first opening (26b) to engage the breakaway feature to the delivery tube.

10. The method according to claim 8, further comprising: cutting the breakaway feature from the flat sheet of material; cutting the first opening in the breakaway feature; cutting a second opening in the breakaway feature separate from the first opening; as well as A portion of a mechanical deployment system is extended through the second opening to engage the breakaway feature to the delivery tube.

11. The method according to claim 8, further comprising: The breakaway feature is cut from the radiopaque flat sheet material.

12. The method according to claim 8, further comprising: inserting a distal portion of the breakaway feature into the lumen of the embolic coil; as well as A proximal portion of the breakaway feature is extended proximally from the proximal end of the embolic coil.

13. The method according to claim 8, wherein Attaching the breakaway feature to the first end of the embolic coil includes welding the breakaway feature to the first end of the embolic coil.

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