Embolic coil proximal connecting element and stretch resistant fiber
13 claims: 2 independent, 11 dependent
- 1塞栓インプラントであって、内部を通る管腔、近位端、及び遠位端を含む、塞栓コイルと、前記塞栓コイルの前記近位端近くで前記塞栓コイルに 溶接さ れた脱離特徴部と、前記脱離特徴部に係合し、前記塞栓コイルの前記管腔を通って延在し、前記塞栓コイルの前記遠位端近くで前記塞栓コイルに貼着された耐延伸性繊維と、を備え、 前記塞栓コイルの前記管腔が、内径を含み、 前記脱離特徴部が、前記管腔から近位に配設された近位部分と、前記管腔内に配設された遠位部分と、を備え、 前記近位部分が、前記管腔の前記内径よりも大きい第1の幅を含み、 前記遠位部分が、前記管腔の前記内径とほぼ等しい第2の幅を有する幅広セクションと、前記管腔の前記内径よりも小さい第3の幅を有する幅狭セクションと、前記幅広セクションと前記幅狭セクションとの間のテーパ状セクションと、を含み、 前記耐延伸性繊維は、前記塞栓コイルが再成形される際に、前記塞栓コイルの巻線の分離を制限するのに有効である、塞栓インプラント。
- 2前記耐延伸性繊維が、縫合糸である、請求項1に記載の塞栓インプラント。
- 3前記耐延伸性繊維が、非弾性である、請求項1に記載の塞栓インプラント。
- 4前記脱離特徴部が、放射線不透過性である、請求項1に記載の塞栓インプラント。
- 5前記脱離特徴部が、内部を通る開口部を備え、前記耐延伸性繊維が、前記脱離特徴部の前記開口部を通過し、前記開口部が、前記塞栓コイルの前記近位端から近位に延在し、前記開口部が、機械的送達システムのループワイヤを受容するようにサイズ決め及び位置決めされている、請求項1に記載の塞栓インプラント。
- 6前記脱離特徴部が、内部を通る第1の開口部と、前記第1の開口部とは別個の、内部を通る第2の開口部と、を備え、前記耐延伸性繊維が、前記第1の開口部を通過し、前記第1の開口部の少なくとも一部分が、前記塞栓コイルの前記管腔内に位置決めされており、前記第2の開口部の少なくとも一部分が、前記塞栓コイルの前記近位端から近位に位置決めされている、請求項1に記載の塞栓インプラント。
- 7システムであって、請求項6に記載の塞栓インプラントと、前記第2の開口部を通して位置決めされたループワイヤ、及び前記ループワイヤの開口部を通して位置決めされたプルワイヤ、を含む、機械的送達システムと、を備え、前記脱離特徴部が、前記第1の開口部と前記第2の開口部とを分離するブリッジを更に備え、前記ブリッジが、前記ループワイヤの前記開口部から遠位方向に前記プルワイヤの一部分を支持する、システム。
- 8前記内径が第1の内径であり、 前記塞栓コイルの前記管腔が、非拡張部分と拡張部分とを含み、 前記拡張部分が前記第1の内径を有し、前記非拡張部分が前記第1の内径よりも小さい第2の内径を有する、請求項1に記載の塞栓インプラント。
- 9方法であって、脱離特徴部の第1の開口部に耐延伸性繊維を通すことと、塞栓コイルの管腔を通して前記耐延伸性繊維を延在させることと、 前記塞栓コイルの近位端から近位に前記脱離特徴部の近位部分が延在するように、前記塞栓コイルの前記管腔内に前記脱離特徴部の遠位部分を挿入することと、 前記塞栓コイルの 前記近位端に 前記脱離特徴部を 溶接す ることと、 前 記塞栓コイルの 遠位端に 前記耐延伸性繊維を貼着することと、前記脱離特徴部と前記塞栓コイルの前記 遠位端と の間に、前記耐延伸性繊維に沿って張力を提供することと、を含 み、 前記塞栓コイルの前記管腔が、内径を含み、 前記近位部分が、前記管腔の前記内径よりも大きい第1の幅を含み、 前記遠位部分が、前記管腔の前記内径とほぼ等しい第2の幅を有する幅広セクションと、前記管腔の前記内径よりも小さい第3の幅を有する幅狭セクションと、前記幅広セクションと前記幅狭セクションとの間のテーパ状セクションと、を含む、 方法。
- 10平坦なシート材料から前記脱離特徴部を切断することと、前記脱離特徴部内の前記第1の開口部を切断することと、前記第1の開口部 を 通して機械的 送達シ ステムの一部分を延在させて、前記脱離特徴部を送達チューブに係合させることと、を更に含む、請求項9に記載の方法。
- 11平坦なシート材料から前記脱離特徴部を切断することと、前記脱離特徴部内の前記第1の開口部を切断することと、前記第1の開口部とは別個の、前記脱離特徴部内の第2の開口部を切断することと、前記第2の開口部を通して機械的 送達シ ステムの一部分を延在させて、前記脱離特徴部を送達チューブに係合させることと、を更に含む、請求項9に記載の方法。
- 12放射線不透過性の平坦なシート材料から前記脱離特徴部を切断することを更に含む、請求項9に記載の方法。
- 13前記内径が第1の内径であり、 前記塞栓コイルの前記管腔が、非拡張部分と拡張部分とを含み、 前記拡張部分が前記第1の内径を有し、前記非拡張部分が前記第1の内径よりも小さい第2の内径を有する、請求項9に記載の方法。
Independent claims13
64 paragraphs, as filed
FIELD OF THEINVENTION The present invention relates generally to implantable medical devices, and more particularly to engagement features for releasably mechanically securing an implantable medical device to a delivery system.
Aneurysms can be treated endovascularly by delivering a treatment device to the aneurysm to load the aneurysm's sac with embolic material and/or block the aneurysm's neck to inhibit blood flow to the aneurysm. When loading the aneurysm's sac, the embolic material may promote blood clotting to create a thrombotic mass within the aneurysm. When treating the aneurysm's neck without substantially loading the aneurysm's sac, blood flow to the aneurysm's neck can be inhibited to induce venous congestion within the aneurysm and facilitate the natural formation of a thrombotic mass within the aneurysm.
In some current treatments, multiple embolic coils are used to either load the aneurysm sac or treat the ostium of the aneurysm neck. A common challenge during embolic coil treatment is that the implanted coils and the implanted portions of the partially implanted coils become tangled, making repositioning difficult. In some cases, the physician may not be able to retract the partially implanted coils and may be forced to position the coils in a non-ideal location. An embolic coil that is improperly positioned at the aneurysm neck can potentially have the detrimental effect of obstructing blood flow when mating with the vessel, especially if the ostium and/or sac are overfilled. If a portion of a non-ideally implanted coil becomes dislodged, it may enter an adjacent vessel and promote clot formation, eventually becoming tethered to the aneurysm and thus causing an occlusion that is very difficult to treat. Conversely, if the ostium and/or sac are not fully filled, blood flow may remain within the aneurysm.
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 may be engaged with an implant engagement/deployment system of the delivery member (equivalently referred to herein as an "engagement system" or a "deployment system"). When the embolic coil is in place, the deployment system may release the coil, leaving the coil implanted, and the delivery member may be retracted. Some treatments utilize a mechanical engagement/deployment system that may be actuated by the physician to release the implant by pulling on one or more wires or other elongated members, collectively referred to herein as "pull wires."
Some of the challenges associated with the delivery and deployment of embolic coils with delivery members having mechanical engagement systems include premature release of the coil and migration of the delivery member due to push-back from a densely packed treatment site.
<p>Thus, a need exists for improved methods, devices, and systems for facilitating the implantation of embolic coils and other implants that face similar challenges.</p>
<p>It is an object of the present invention to provide systems, devices, and methods that meet the above-mentioned needs. In some examples presented herein, separation of the coil windings in an embolic coil is reduced or prevented with a stretch-resistant fiber positioned within the lumen of the coil. Reducing or preventing separation of the coil windings can, in some cases, prevent the implanted portion of a partially implanted coil from entangling with the implanted coil, and thereby allow for easier repositioning and/or extraction of some or all of the coil. In some examples presented herein, during delivery of the embolic coil, the distal end of the pull wire is supported by an engagement/detachment feature (equivalently referred to herein as an "engagement feature," "detachment feature," or "key") affixed to the proximal end of the embolic coil. The support provided by the key can, in some cases, reduce the likelihood of the embolic coil being prematurely released. In some examples presented herein, the embolic implant can have a highly flexible proximal portion. The flexibility of the embolic implant can potentially reduce the forces on the delivery member due to push-back from a densely packed treatment site, and thereby reduce migration of the delivery member due to push-back.</p><p>To meet some or all of the needs, an implant is provided having an embolic coil, a stretch resistant fiber extending through the coil, and a detachment feature/key at the proximal end of the coil. The stretch resistant fiber can be effective to limit separation of the windings of the embolic coil. The key can provide an attachment for securing the embolic coil to an engagement system of a delivery tube and for securing the stretch resistant fiber to the proximal end of the embolic coil.</p><p>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: A portion or all of an implant having an embolic coil and stretch-resistant fibers may be positioned within the aneurysm. A portion of the embolic coil may be retracted from the aneurysm. As the portion is retracted from the aneurysm, the stretch-resistant fibers may inhibit the extension of the portion. The embolic coil may be bent, and the stretch-resistant fibers may limit separation of the windings of the embolic coil upon bending.</p><p>The stretch-resistant fiber can be positioned to extend within a lumen of the embolic coil. The stretch-resistant fiber can be under tension along a majority of the length of the stretch-resistant fiber.</p><p>The implant may be secured to the delivery system with a key engaged with the stretch resistant fiber. To secure the implant to the delivery system, a loop wire of the delivery system may be positioned through the key and a pull wire may be positioned through an opening in the loop wire. When the implant is secured to the delivery system, the pull wire may be supported by the key both proximally from the loop wire and distally from the loop wire.</p><p>During delivery and/or positioning of the implant, the key can be visualized radiographically.</p><p>The key can be released from the delivery system, thereby releasing the implant from the delivery system. When the implant is released, the key can remain attached to the implant.</p><p>An exemplary embolic implant may include an embolic coil, a detachment feature, and a stretch-resistant fiber. The detachment feature may be affixed to the embolic coil at a proximal end of the embolic coil. The stretch-resistant fiber may engage the detachment feature, extend through a lumen of the embolic coil, and be affixed to the embolic coil at a distal end of the embolic coil. Configured in this manner, the stretch-resistant fiber may be effective to limit separation of the windings of the embolic coil when the embolic coil is reshaped.</p><p>The stretch resistant fiber can be a suture. The stretch resistant fiber can be inelastic.</p><p>The detachment feature may be radiopaque.</p><p>The detachment 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.</p><p>The detachment feature can have a single opening sized to receive the loop wire of the mechanical delivery system and through which the stretch resistant fiber passes.</p><p>Alternatively, the detachment 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 wire of a 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.</p><p>An exemplary system may include an exemplary embolic implant having a detachment feature with two separate openings and a mechanical delivery system including a loop wire and a pull wire. The stretch resistant fiber may pass through one of the two openings and the loop wire may pass through the other of the two openings. The pull wire may be positioned through the opening of the loop wire, thereby anchoring the implant 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 may support a portion of the pull wire distally from the loop opening of the loop wire.</p><p>The detachment feature can have a proximal portion disposed proximally from the lumen of the embolic coil and a distal portion disposed within the lumen, The proximal portion can have a width dimension greater than an inner diameter of the embolic coil lumen and the distal portion can have a width dimension approximately equal to the inner diameter of the embolic coil lumen.</p><p>An exemplary method for constructing or designing an embolic implant, such as the exemplary implants described herein, can include one or more of the following steps, presented in no particular order, and the method can include additional steps not included herein: A detachment feature can be cut from a flat sheet of material. One or more openings can be cut from the detachment feature. A stretch-resistant fiber can be threaded through the openings in the detachment feature. The stretch-resistant fiber can extend through a lumen of the embolic coil. The detachment feature can be affixed to one end of the embolic coil. The stretch-resistant fiber can be affixed to the other end of the embolic coil. Tension can be provided along the stretch-resistant fiber between the detachment feature and a second end of the embolic coil.</p><p>A portion of the mechanical deployment system can extend through an opening in the detachment feature to engage the detachment feature with a delivery tube. The mechanical deployment system can extend through the same opening through which the stretch-resistant fiber is threaded or through an opening in the detachment feature that is separate from the opening through which the stretch-resistant fiber is threaded.</p><p>The break-away features may be cut from a flat sheet of radiopaque material.</p><p>A distal portion of the detachment feature can be inserted into the lumen of the embolic coil and a proximal portion of the detachment feature can extend proximally from a proximal end of the embolic coil. The embolic coil and detachment feature can be selected such that the proximal portion of the detachment feature is wider than an 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.</p><p>The detachment feature can be welded to the embolic coil to affix the detachment feature to the embolic coil.</p>
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, in which like numerals indicate like structural elements and features in the various drawings. The drawings are not necessarily to scale, emphasis instead being placed on illustrating the principles of the invention. The figures depict one or more implementations of the apparatus of the present invention, by way of example only and not by way of limitation.
<figref num="1A">1 is an illustration of an embolic implant, according to an embodiment of the present invention.</figref><figref num="1B">1 is an illustration of an embolic implant, according to an embodiment of the present invention.</figref><figref num="2A">1 is an illustration of a detachment feature having stretch resistant fiber threaded therethrough, according to an aspect of the present invention.</figref><figref num="2B">1 is an illustration of a detachment feature having stretch resistant fiber threaded therethrough, according to an aspect of the present invention.</figref><figref num="3">1 is an illustration of a stretch-resistant fiber being inserted into the lumen of an embolic coil, according to an aspect of the present invention.</figref><figref num="4">1 is an illustration of a stretch resistant fiber exiting the lumen of an embolic coil, according to an aspect of the present invention.</figref><figref num="5A">1 is an illustration of a detachment feature being inserted into a lumen of an embolic coil, according to an aspect of the present invention.</figref><figref num="5B">1 is an illustration of a detachment feature being inserted into a lumen of an embolic coil, according to an aspect of the present invention.</figref><figref num="6A">1 is an illustration of a detachment feature affixed to an embolic coil, according to an aspect of the present invention.</figref><figref num="6B">1 is an illustration of a detachment feature affixed to an embolic coil, according to an aspect of the present invention.</figref><figref num="7">1 is an illustration of a stretch resistant fiber affixed to the end of an embolic coil, according to an aspect of the present invention.</figref><figref num="8A">1 illustrates the time sequence of embolic coil stretching as a result of non-optimal deployment of stretch-resistant fibers.</figref><figref num="8B">1 illustrates the time sequence of embolic coil stretching as a result of non-optimal deployment of stretch-resistant fibers.</figref><figref num="8C">1 illustrates the time sequence of embolic coil stretching as a result of non-optimal deployment of stretch-resistant fibers.</figref><figref num="9">1 is an illustration of an embolic coil positioned within an aneurysm, according to an aspect of the present invention.</figref><figref num="10A">1 is an illustration of tangled embolic coils.</figref><figref num="10B">As an illustration of the problems with the prior art, an illustration of a tangled coil in an elongated state is shown.</figref><figref num="11">1 is an illustration of a stretch resistant fiber that inhibits tangling and elongation of an embolic coil, according to an aspect of the present invention.</figref><figref num="12">FIG. 1 is a flow diagram outlining method steps that may be performed as part of an aneurysm treatment according to an aspect of the present invention.</figref><figref num="13">1 is an illustration of an embolic implant secured to a delivery tube, according to an embodiment of the present invention.</figref><figref num="14A">1 illustrates a sequence of steps for releasing an embolic implant from a delivery tube, according to an embodiment of the present invention.</figref><figref num="14B">1 illustrates a sequence of steps for releasing an embolic implant from a delivery tube, according to an embodiment of the present invention.</figref><figref num="14C">1 illustrates a sequence of steps for releasing an embolic implant from a delivery tube, according to an embodiment of the present invention.</figref><figref num="14D">1 illustrates a sequence of steps for releasing an embolic implant from a delivery tube, according to an embodiment of the present invention.</figref><figref num="15">1 is an illustration of an end of an embolic implant including a detachment feature that expands the inner diameter of the embolic coil, according to an aspect of the present invention.</figref>
It is an object of the present invention to achieve more accurate and repeatable implant detachment. More specifically, it is an object of the present invention to facilitate implantation of embolic coils and other implants that face challenges such as difficulty in repositioning a partially implanted implant, delivery systems that shift position due to being pushed back during implantation, and/or premature release of the implant. To meet some or all of these needs, an exemplary implant may include stretch-resistant fibers to limit stretch and other deformation of the embolic portion of the implant (e.g., the embolic coil) and detachment features to which the stretch-resistant fibers may be anchored and to which the delivery system may be releasably attached.
To facilitate repositioning of the implant, the stretch-resistant fiber can extend through the embolic coil to limit separation of the coil's windings when the coil is bent and pulled. By limiting separation of the windings, the embolic coil is less likely to tangle when partially implanted and less likely to stretch or otherwise deform when retracted when partially implanted. This allows the embolic coil to be more easily repositioned. In some embodiments, the release feature can include two separate openings, one for anchoring the stretch-resistant fiber and the other for engaging the engagement system. The dual-opening release feature can reduce potential manufacturing challenges to provide reliable positioning of the stretch-resistant fiber and thus more reliably provide an implant that can be more easily repositioned.
To reduce the effects of pushback during implantation, a detachment feature can be sized and affixed to the embolic coil to provide an embolic coil implant with a highly flexible proximal section. The embolic coil implant with a highly flexible proximal section can reduce the pushback force on the delivery tube and thereby reduce the effects of delivery tube shifting. Additionally or alternatively, the detachment feature can be sized to mate with a delivery tube with a highly flexible distal section, which can reduce the effects of delivery tube shifting. When an embolic coil implant with a highly flexible proximal section mates with a delivery tube with a highly flexible distal section, the combination of the flexible distal section of the delivery tube and the flexible proximal section of the implant can further reduce the effects of delivery tube shifting.
To reduce instances of premature deployment, the detachment feature may include a bridge for supporting the pull wire. The detachment feature may be releasably attached to a mechanical engagement/deployment system on the delivery tube. The detachment feature may include an opening through which a loop wire of the mechanical engagement system may pass. In some examples, the detachment feature may further include a bridge positioned distally from the opening through which a distal portion of the pull wire may rest. The bridge may restrain the pull wire from deforming due to engagement with the loop wire, thus reducing the likelihood of premature release of the implant due to bending of the pull wire.
FIG. 1A is an illustration of an implant 10a including an embolic coil 12 having a lumen 13 therethrough, a detachment feature 18a, and a stretch-resistant fiber 16. A portion of the coil 12 and weld 42 are illustrated in a cutaway view for illustrative purposes. The detachment feature 18a may be positioned partially within the lumen 13 of the coil 12 and may extend outwardly from 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 positioned between the distal opening 24a and the proximal opening 22a. The detachment feature 18a may include a proximal tab 38 sized to fit within the lumen of a delivery tube. The stretch resistant fibers 16 may be secured to the end of the embolic coil 12 opposite the end to which the detachment feature 18a is attached at a weld 44 or other suitable attachment.
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 profile, providing even more flexibility in directions into and out of the plane of the image.
The detachment feature 18a can be sufficiently secured to the coil 12 with the attachment 42 without fusing any of the turns of the coil 12 (as illustrated) or by fusing a small number of turns (e.g., 5 or 4 turns or less). Compared to known solutions in which typically 10 or 11 or more turns are soldered together (with limited control over the number of turns fused), the attachment 42 to the coil 12 can be achieved with significantly fewer fused coil turns. By reducing the number of fused turns, the proximal section of the implant 10a can have increased flexibility compared to known designs that rely on fusing turns from the proximal end of the embolic coil.
FIG. 1B is an illustration of an alternatively constructed implant 10b having elements described in connection with FIG. 1A with like reference numbers indicating like elements. A portion of the coil 12 and weld 42 illustrated in cutaway view for illustrative purposes. In comparison to the implant 10a illustrated in FIG. 1A, the implant 10b may have an alternative release feature 18b having a single opening 26b that provides an opening through which a mechanical engagement system can be engaged and through which the stretch-resistant fiber 16 can be looped. The release feature 18b illustrated in FIG. 1B also lacks the extended tapered region of the release feature 18a illustrated in FIG. 1A. While the tapered region of the detachment feature 18a illustrated in FIG. 1A may provide a more flexible proximal section of the implant 10a compared to the implant 10b in FIG. 1B, the detachment feature 18b illustrated in FIG. 1B may nevertheless provide greater flexibility than known embolic coil implants by being flat and providing flexibility in directions into and out of the plane of the image, and the low profile attachment portion 42 may provide greater flexibility than designs that rely on fusing windings from the proximal end of the embolic coil.
Figures 2A and 2B-7 illustrate a sequence of steps for constructing the implants 10a and 10b illustrated in Figures 1A and 1B. Figures 2A and 2B illustrate the stretch resistant fiber 16 passing through the detachment features 18a, 18b. The detachment 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 affixed to the embolic coil 12.
2A illustrates a dual aperture detachment feature 18a having a proximal portion 32 sized to engage a mechanical engagement system and/or a delivery tube. The proximal portion 32 is illustrated as having a width W1. The dual aperture detachment feature 18a can have a distal portion 34 sized to fit within the lumen 13 of an embolic coil. The distal portion 34 can have a wider section having a width W2 approximately the same width 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 detachment feature 18a can have a proximal tab 38 that is narrower than the proximal portion 32 and sized to fit within the lumen of a delivery tube.
2B illustrates a single-opening detachment feature 18b having a proximal portion 32 sized to engage a mechanical engagement system and/or a delivery tube. The proximal portion 32 is illustrated having a width W1. The single-opening detachment feature 18b can have a distal portion 34b that is narrower than the proximal portion 32 and sized to fit within the lumen 13 of the coil 12. The single-opening detachment feature 18b can have a proximal tab 38 that is narrower than the proximal portion 32 and sized to fit within the lumen of a delivery tube.
After the release features 18a, 18b are formed, the stretch resistant fiber 16 can be threaded through the distal opening 24a of the dual-opening release feature 18a or through the single opening 26b of the single-opening release feature 18b.
Figure 3 is an illustration of a free end of a stretch-resistant fiber 16 that has been inserted into the proximal end 15 of an embolic coil 12. In the process illustrated in Figure 3, the stretch-resistant fiber 16 can be looped through detachment features 10a, 10b as illustrated in Figures 2A and 2B.
FIG. 4 is an illustration of the free ends of the stretch-resistant fibers 16 exiting the lumen 13 of the embolic coil 12 at the distal end 14 of the embolic coil 12 .
5A and 5B are illustrations of the detachment features 18a, 18b being inserted into the lumen 13 of the embolic coil 12. After exiting the distal end 14 of the embolic coil 12, the free ends of the stretch-resistant fibers 16 can be pulled further, as shown by the arrows in FIG. 4, 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 illustrated in FIGS. 5A and 5B and shown by the arrows. Prior to entry of the detachment features 18a, 18b into the lumen 13 of the embolic coil 12, the embolic coil can have an inner diameter D as shown in FIG. 5A. The proximal portion 34 of the detachment features 18a, 18b can be sized to have a width greater than at least a portion of the distal portion 34 approximately equal to the inner diameter D for a snug fit. Alternatively or additionally, at least a portion of distal portion 34 may have a width greater than diameter D to create an interference fit. Alternatively or additionally, at least a portion of distal portion 34 may have a width less than diameter D to allow for a more flexible coil 12 near proximal end 15 thereof.
6A and 6B are illustrations of detachment features 10a, 10b with distal portion 34 fully inserted into lumen 13 of embolic coil 12, as well as detachment features 18a, 18b affixed to embolic coil 12 by welds 42 or other attachments. In both Figures 6A and 6B, detachment features 18a, 18b are illustrated with distal portion 34 having a width that exceeds at least a portion of a length of distal portion 34 that is approximately equal to inner diameter D of lumen 13 of embolic coil 12.
7 is an illustration of a stretch-resistant fiber 16 affixed to the distal end of an embolic coil 12. After affixing the detachment features 18a, 18b, or at least positioning the detachment features 18a-18b as illustrated in FIGS. 6A and 6B, the stretch-resistant fiber 16 can be pulled tight to reduce slack in the fiber 16 and/or create tension in the fiber 16, and the fiber 16 can be affixed with a weld 44 or other attachment. After the fiber 16 is attached, the fiber can be substantially stretch-resistant to resist significant elongation due to forces applied to the embolic coil 12 during preparation for treatment, delivery of the implants 10a, 10b, positioning the implants at the treatment site, retraction of the implants, and deployment of the implants. In other words, the stretch-resistant fibers 16 can be effective in limiting the elongation of the embolic coil 12 when the embolic coil 12 is retracted from the aneurysm, and the stretch-resistant fibers 16 can be effective in limiting separation of the windings within the embolic coil 12 when the embolic coil 12 is bent.
8A-8C illustrate a time sequence in which the embolic coil 12 may be stretched as a result of non-optimal placement of the stretch-resistant fiber 16. FIG. 8A illustrates non-optimal placement of the fiber 16 in a single aperture detachment feature 18b. The fiber 16 may be looped over a non-optimal section of the detachment feature 18b, such that movement of the fiber 16 as illustrated in FIG. 8B may disengage the fiber 16 from the non-optimal position, and movement of the fiber 16 as illustrated in FIG. 8C may stretch the embolic coil 12 at least until the fiber 16 re-engages the detachment feature 18a. Thus, a manufacturing challenge is to prevent the fiber 16 from being positioned in a non-optimal location as illustrated in FIG. 8A when the attachment process illustrated in FIG. 7 is performed. If, after fabrication is complete, the fibers 16 are removed from a non-optimal location, such as that illustrated in FIG. 8B, the embolic coil 12 may be stretched or otherwise deformed, as illustrated in FIG. 8C, when manipulating the implant 10b, such as during repositioning during treatment.
An advantage of the dual opening release feature 18a is that during manufacturing of the implant 10a illustrated in FIG. 1A, the stretch-resistant fibers 16 are less likely to loop over non-optimal sections of the release feature 18a.
9 is an illustration of embolic implant(s) 10 delivered through a delivery catheter 200 and positioned within an aneurysm A of a blood vessel BV. The implant(s) may loop and bend within the aneurysm sac to form a thrombotic mass. The implant(s) may loop back on themselves and/or loop next to other implants. As the aneurysm A gradually fills, overlapping portions of the implants 10 may be pushed into one another.
FIG. 10A illustrates an embolic coil 12 in which the stretch-resistant fibers 16 do not become entangled when overlapping portions of the coil are forced into one another. 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. FIG. 10B illustrates a portion of an embolic coil 12 that is stretched by force F to a length L2 that is longer than the length L1 of the section illustrated in FIG. 10A. FIG. 10B illustrates a scenario in which a physician may attempt to retract a tangled, partially implanted embolic coil, and may not only be unable to retract the coil, but may also exacerbate an already difficult procedure by now having to position a deformed, stretched coil. Tangling may be more likely when the windings of an embolic coil become separated, for example, by bending, or when the coil is more tightly compressed by dense packing.
FIG. 11 is an illustration of exemplary embolic coils 12, each having a stretch-resistant fiber 16 that is prevented from tangling and stretching, according to an embodiment of the present invention. Each coil 12 is illustrated as having a bent portion 20. The stretch-resistant fiber 16 may shift within the lumen 13 of each coil to allow the coil 12 to flex and bend as needed when implanted. The fiber 16 may have sufficient tension to limit the amount of separation between the turns of the bent portion 20. The separation of the turns may be limited to prevent the turns of two adjacent coils 12 from tangling, as illustrated in FIG. 10A. FIG. 11 also illustrates a force F applied to a portion 40 of the coil 12, where tension in the stretch-resistant fiber 16 prevents the portion 40 from stretching. FIG. 11 illustrates a scenario in which a physician may successfully retract a partially implanted embolic coil 12 with a stretch-resistant fiber 16 threaded therethrough.
12 is a flow diagram illustrating a method 500 including steps that may be performed as part of an aneurysm treatment using the exemplary implants 10, 10a, 10b as described herein. At step 510, an implant having an embolic coil and stretch-resistant fibers may be positioned at least partially within the aneurysm sac. At step 520, a portion of the embolic coil may be bent. At step 530, the stretch-resistant fibers may inhibit separation of the windings in the bent portion of the embolic coil as the coil is bent. At step 540, some or all of the implanted portion of the implant may be retracted from the aneurysm. At step 550, the stretch-resistant fibers may inhibit elongation of the embolic coil as the implant is retracted.
FIG. 13 is an illustration of an exemplary embolic implant 10, such as any of the implants 10a, 10b illustrated in FIGS. 1A and 1B or otherwise described herein, secured to a delivery tube 300. Exemplary delivery tubes and engagement/deployment systems are described in U.S. Patent Publication No. 2019/0192162 and U.S. Patent Application Publication No. 15/964,857, each of which is incorporated herein by reference. The delivery tube 300 can include a notch 310 sized to receive the proximal portion 32 of the release feature 18 of the implant 10, which in turn can be sized to fit within the notch 310 of the delivery tube 300. FIG. 13 illustrates a side view of the implant 10, highlighting the flattened profile of the release feature 18. 1A and 1B, the implant 10 may have a highly flexible proximal portion by the detachment feature 18 being flat and/or being secured to the coil 12 without fusing any of the coil windings. The detachment feature 18 may also be tapered to provide increased flexibility in the direction into and out of the plane of the image. The detachment feature 18 may further include a proximal tab 38 positioned within the lumen of the delivery tube 300.
During aneurysm occlusion treatment, the lack of flexibility of the proximal portion of known embolic implants and/or the lack of flexibility of the distal portion of the delivery tube may cause the delivery tube to be pulled back from the treatment site or otherwise move out of place while the implant is in place within the aneurysm. Thus, a delivery tube with a more flexible distal portion and an implant with a more flexible proximal portion, alone or in combination, may provide a more stable system for delivering the implant. However, flexible structures may be prone to deformation or expansion during manipulation. The stretch-resistant fibers 16 and/or detachment features 18, alone or in combination, may support the coil 12 and inhibit deformation and expansion of the coil 12 in accordance with the principles described herein. It is an object of the present invention to provide an implant 10 having a highly flexible proximal portion and/or configured to mate with a delivery tube 300 having a highly flexible distal portion.
Figure 14A is an illustration of an implant 10 and a delivery tube 300 configured to deliver and position the implant 10. Figures 14B-14D are illustrations of a sequence of steps for releasing an exemplary embolic implant 10 from the delivery tube 300. A portion of the delivery tube 300 has been cut away for illustrative purposes.
14A illustrates an engagement system including a pull wire 140 and a loop wire 400 locked within the release feature 18 of the implant 12. The delivery tube 300 can include a compressible portion 306 that can be compressed. The loop wire 400 can have an opening 405 at a distal end 404 of the loop wire 400, which can be placed through the opening 22a of the release feature 18. Once the pull wire 140 is placed through the opening 405, the implant 12 is now secured.
The release feature 18 may include a bridge 28 positioned distally from the loop wire opening 405 and positioned to support a distal portion of the pull wire 140 distal to where the loop wire opening 405 is supported by the pull wire 140. So configured, the bridge 28 may support the distal portion of the pull wire 140 such that when the loop wire 400 tugs on the pull wire 140 at the loop opening 405, the bridge 28 may restrain 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 where the loop wire opening 405 is supported by the pull wire 140. The combination of the bridge 28 and the proximal tab 38 may restrain the pull wire 140 from deforming due to the force applied by the loop wire 400. The delivery tube 300 may be releasably attached to the implant 10 during delivery of the implant 10 through the vasculature and while the implant 10 is positioned at the treatment site, as illustrated in Figure 14A. The bridge 28 may reduce the likelihood of premature release of the implant 10 due to bending of the pull wire 140 due to force from the loop wire 400.
The bridge 28 may separate the proximal and distal openings 22a, 24a in a dual-opening implant as illustrated. It is also contemplated that a single-opening implant may be adapted to include a structure that may function to support a 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.
FIG. 14B illustrates the pull wire 140 being retracted proximally to begin the release sequence of the implant 10. FIG. 14C illustrates the moment the pull wire 140 exits the opening 405 and is unwound from the wire loop 400. The distal end 404 of the wire loop 400 drops out and exits the locking portion 18. As can be seen, there is now nothing holding the implant 10 to the delivery tube 300. FIG. 14D illustrates the end of the release sequence. Now the compressible portion 306 expands/returns to its original shape and "springs" forward. An elastic force E is applied by the distal end 304 of the delivery tube 300 to the medical device 10, "pushing" it away and ensuring clean separation and delivery of the medical device 10.
FIG. 15 is a cross-sectional view of a proximal section of an alternatively constructed implant 10c having elements described in connection with FIG. 1A with like reference numbers indicating like elements. Compared to the implant 10a illustrated in FIG. 1A, the implant 10c illustrated in FIG. 15 may have an alternative detachment feature 18c. The detachment feature 18c illustrated in FIG. 18c may have a portion with a width D2 sized to fit within a lumen 13 of an embolic coil 12 having an inner diameter D1. The width D2 of the detachment feature 18c may be greater than the inner diameter D1 of the coil lumen 13 such that when the detachment feature 18c is positioned within the lumen 13, a proximal portion of the lumen 13 expands to a diameter D2 to accommodate the width D2 of the detachment feature 18c. Configured in this manner, the expanded portion of the coil 12 may provide a compressive force against the section of the detachment feature having the width D2 to help secure the detachment feature 18c to the coil 12.
1A, the bridge 28c may extend proximally from the proximal end of the embolic coil 12. So configured, in some configurations, it is not necessary to insert the pull wire 140 into the lumen 13 of the embolic coil 12 that is supported by the bridge 28c. By limiting the length of the pull wire 140 that is inserted into the embolic coil 12, the flexibility of the proximal section of the embolic coil can be increased.
The implant 10c illustrated in Figure 15 may be constructed according to the principles illustrated in Figures 2A and 2B-7. The implant 10c illustrated in Figure 15 may be used according to the principles illustrated in Figures 9 and 11-14D.
The term "about" or "approximately" as used herein with respect to any numerical value or range of numerical values indicates a suitable dimensional tolerance that allows a portion of a component or a collection of components to function according to its intended purpose as described herein. More specifically, "about" or "approximately" may refer to a range of values of ±20% of the recited value, for example, "about 90%" may refer to a range of values of 71% to 99%.
The descriptions contained herein are examples of embodiments of the invention and are not intended to limit the scope of the invention in any way. As described herein, the invention contemplates many variations and modifications of the implant and methods for making and using the implant, including alternative materials, alternative geometries of the component parts, alternative positioning of the component parts relative to one another, etc. These modifications will be apparent to those skilled in the art to which the invention pertains and are contemplated to be within the scope of the following claims.
[Embodiments] (1) A method comprising: positioning part or all of an implant including an embolic coil and a stretch-resistant fiber within an aneurysm; retracting a first portion of the embolic coil from the aneurysm; and limiting the extension of the first portion of the embolic coil with the stretch-resistant fiber as the first portion is retracted from the aneurysm.
(2) The method of embodiment 1, further comprising positioning the stretch-resistant fiber to extend within a lumen of the embolic coil.
(3) The method of embodiment 1, further comprising bending a second portion of the embolic coil and using the stretch resistant fiber to limit separation of the windings within the second portion of the embolic coil while bending the second portion of the embolic coil.
(4) The method of claim 1, further comprising: securing the implant to a delivery system with a key engaged with the stretch resistant fiber; and releasing the key from the delivery system, thereby releasing the implant from the delivery system.
(5) The method of embodiment 4, wherein the step of securing the implant to the delivery system further comprises positioning a loop wire of the delivery system through the key and positioning a pull wire of the delivery system through an opening in the loop wire, the method further comprising supporting a first portion of the pull wire by the key positioned distally relative to the loop opening and supporting a second portion of the pull wire by the key positioned proximally relative to the loop opening.
(6) An embolic implant comprising: an embolic coil including a lumen therethrough, a proximal end, and a distal end; a detachment feature affixed to the embolic coil near the proximal end of the embolic coil; and a stretch-resistant fiber engaging the detachment feature and extending through the lumen of the embolic coil and affixed to the embolic coil near the distal end of the embolic coil, wherein the stretch-resistant fiber is effective to limit separation of a winding of the embolic coil when the embolic coil is reshaped.
(7) The embolic implant of embodiment 6, wherein the stretch-resistant fiber is a suture.
(8) The embolic implant of embodiment 6, wherein the stretch-resistant fibers are inelastic.
(9) The embolic implant of embodiment 6, wherein the detachment feature is radiopaque.
(10) The embolic implant of embodiment 6, wherein the detachment feature has an opening therethrough, the stretch-resistant fiber passes through the opening in the detachment feature, the opening extends proximally from the proximal end of the embolic coil, and the opening is sized and positioned to receive a loop wire of a mechanical delivery system.
(11) The embolic implant of embodiment 6, wherein the detachment feature comprises a first opening therethrough and a second opening therethrough separate 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, and at least a portion of the second opening is positioned proximally from the proximal end of the embolic coil.
(12) A system comprising: the embolic implant of embodiment 11; and a mechanical delivery system including a loop wire positioned through the second opening and a pull wire positioned through an opening in the loop wire, wherein the detachment feature further comprises a bridge separating the first opening and the second opening, the bridge supporting a portion of the pull wire distally from the opening in the loop wire.
(13) The embolic implant of embodiment 6, wherein the lumen of the embolic coil includes an inner diameter, and the detachment feature comprises a proximal portion disposed proximally from the lumen and a distal portion disposed within the lumen, the proximal portion including a first width having a dimension greater than the inner diameter of the lumen, and the distal portion including a second width having a dimension approximately equal to the inner diameter of the lumen.
(14) A method comprising: threading a stretch-resistant fiber through a first opening of a detachment feature; extending the stretch-resistant fiber through a lumen of an embolic coil; affixing the detachment feature to a first end of the embolic coil; affixing the stretch-resistant fiber to a second end of the embolic coil opposite the first end; and providing tension along the stretch-resistant fiber between the detachment feature and the second end of the embolic coil.
(15) The method of embodiment 14, further comprising cutting the break-away feature from a flat sheet of material, cutting the first opening in the break-away feature, and extending a portion of a mechanical deployment system through the first opening (26b) to engage the break-away feature with a delivery tube.
(16) The method of embodiment 14, further comprising cutting the break-away feature from a flat sheet of material, cutting the first opening in the break-away feature, cutting a second opening in the break-away feature separate from the first opening, and extending a portion of a mechanical deployment system through the second opening to engage the break-away feature with a delivery tube.
17. The method of claim 14, further comprising cutting the breakaway feature from a radiopaque flat sheet material.
(18) The method of claim 14, further comprising inserting a distal portion of the detachment feature into the lumen of the embolic coil and extending a proximal portion of the detachment feature proximally from the proximal end of the embolic coil.
(19) The method of embodiment 18, further comprising: selecting the embolic coil such that the lumen comprises an inner diameter; and selecting the detachment feature such that the proximal portion of the detachment feature comprises a first width having a dimension greater than the inner diameter of the lumen and the distal portion of the detachment feature comprises a second width having a dimension approximately equal to the inner diameter of the lumen.
(20) The method of embodiment 14, wherein affixing the detachment feature to the first end of the embolic coil comprises welding the detachment feature to the first end of the embolic coil.
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Every citation, both ways
| Document | Relation | Office | Cited during |
|---|---|---|---|
| JP2021058586A | Cited by | Japan | Search report |
| JP2013212372A | Cites | Japan | – |
| JP2019111339A | Cites | Japan | – |
| JP2012000464A | Cites | Japan | – |
22 members in 6 offices
Members22
| Document | Office | Kind | |
|---|---|---|---|
| US2021077118A1 | United States of America | A1 | |
| CN112515726A | China | A | |
| EP3795097A1 | European Patent Office (EPO) | A1 | |
| JP2021045547A | Japan | A | |
| KR20210032908A | Republic of Korea | A | |
| US2021338248A1 | United States of America | A1 | |
| US11439403B2 | United States of America | B2 | |
| US2022387045A1 | United States of America | A1 | |
| CN115607217A | China | A | |
| EP4119064A1 | European Patent Office (EPO) | A1 | |
| KR20230011880A | Republic of Korea | A | |
| JP2023014032A | Japan | A | |
| JP7508317B2This record | Japan | B2 | |
| US12127744B2 | United States of America | B2 | |
| EP3795097B1 | European Patent Office (EPO) | B1 | |
| EP3795097C0 | European Patent Office (EPO) | C0 | |
| ES2999631T3 | Spain | T3 | |
| EP4119064B1 | European Patent Office (EPO) | B1 | |
| EP4119064C0 | European Patent Office (EPO) | C0 | |
| ES3031893T3 | Spain | T3 | |
| US12376859B2 | United States of America | B2 | |
| CN112515726B | China | B |
8 legal events, as the office reported them to INPADOC
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| Certificate of patent or registration of utility modelJAPANESE INTERMEDIATE CODE: R150R150 | R150 | |
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Numbers
- Publication
- 7508317
- Application
- 155306
Titles2
- Japanese
- 塞栓コイル近位接続要素及び耐延伸性繊維
- English
- Embolic coil proximal connecting element and stretch-resistant fiber
Classification
- CPC, 9
- A61B17/12113
- A61B17/12154
- A61B17/1214
- A61B17/1215
- A61B2017/1205
- A61B2017/00526
- A61B2017/12054
- A61B2017/0092
- A61B2017/00477
- IPC, 1
- A61B17 00
