Aneurysm device and delivery system

Abstract

A braid for treating an aneurysm can include a first radially expandable segment operable to move from a collapsed state within a microcatheter to a deployed state distal of the microcatheter. The first radially expandable segment can be capable of radially expanding to form an outer occlusive sack in the aneurysm in the deployed state. The braid can also include a second radially expandable segment operable to move from the collapsed state within the microcatheter to the deployed state distal of the microcatheter, wherein the second radially expandable segment is capable of radially expanding inside the outer occlusive sack to form an inner occlusive sack in the outer occlusive sack in the deployed state. An expansion mechanism can be included and be disposed at a proximal end of the first and second radially expandable segments.

Description

FIELD

This disclosure relates to medical instruments, and more particularly, systems and devices for aneurysm therapy.

BACKGROUND

Aneurysms can be complicated and difficult to treat. For example, treatment access may be limited or unavailable when an aneurysm is located proximate critical tissues. Such factors are of particular concern with cranial aneurysms due to the brain tissue surrounding cranial vessels the corresponding limited treatment access.

Prior solutions have included endovascular treatment access whereby an internal volume of the aneurysm sac is removed or excluded from arterial blood pressure and flow. In this respect, because the interior walls of the aneurysm may continue being subjected to flow of blood and related pressure, aneurysm rupture remains possible.

Alternative to endovascular or other surgical approaches can include occlusive devices. Such devices have typically incorporated multiple embolic coils that are delivered to the vasculature using microcatheter delivery systems. For example, when treating cranial aneurysms, a delivery catheter with embolic coils is typically first inserted into non-cranial vasculature through a femoral artery in the hip or groin area. Thereafter, the catheter is guided to a location of interest within the cranium. The sac of the aneurysm can then be filled with the embolic material to create a thrombotic mass that protects the arterial walls from blood flow and related pressure. However, such occlusive devices do have certain shortcomings, including mass effect, which can cause compression on the brain and its nerves.

One particular type of occlusive approach endeavors to deliver and treat the entrance or “neck” of the aneurysm as opposed to the volume of the aneurysm. In such “neck” approaches, by minimizing blood flow across the neck, then a cessation of flow into the aneurysm may be achieved. In turn, a thrombotic mass may naturally form without having to deliver embolic materials, as previously described. This is preferable to masses formed from embolic material since a natural mass can improve healing by reducing possible distention from arterial walls and permits reintegration into the original parent vessel shape along the neck plane of the aneurysm. It is understood that the neck plane is an imaginary surface where the inner most layer of the parent wall would be but for the aneurysm. However, neck-occlusive approaches are not without drawbacks. It is desired to block the neck of the aneurysm in the parent vessel. Furthermore, embolic coils do not always effectively treat aneurysms as re-canalization of the aneurysm and/or coil compaction can occur over time.

It is therefore desirable to have a device which easily, accurately, and safely occludes a neck of an aneurysm or other arterio-venous malformation in a parent vessel without blocking flow into perforator vessels communicating with the parent vessel.

SUMMARY

In some embodiments, the present disclosure relates to a braid for treating an aneurysm. The braid can include a first radially expandable segment operable to move from a collapsed state within a microcatheter to a deployed state distal of the microcatheter. The first radially expandable segment can be capable of radially expanding to form an outer occlusive sack in the aneurysm that seals the neck of the aneurysm in the deployed state. The braid can also include a second radially expandable segment operable to move from the collapsed state within the microcatheter to the deployed state distal of the microcatheter, wherein the second radially expandable segment is capable of radially expanding inside the outer occlusive sack to form an inner occlusive sack in the outer occlusive sack in the deployed state. An expansion mechanism can be included and be disposed at a proximal end of the first and second radially expandable segments.

In some embodiments, the expansion mechanism can include an expansion ring with an opening. A distal end of the braid can be inserted through the opening and then the proximal end can be folded over the opening.

In some embodiments, the expansion mechanism can include an opening and a plurality of radially flexible elements. Each flexible element can be capable of expanding from a collapsed condition in the microcatheter to an expanded condition in the deployed state distal of the microcatheter to support a proximal portion of the outer occlusive sack. Each radially flexible element can be evenly radially spaced about a central axis of the expansion mechanism. The central axis of the expansion mechanism can be axially aligned with a central axis of the first and second radially expandable segments.

In some embodiments, the expansion mechanism can include at least four radially spaced flexible elements that extend from an expansion ring (e.g. a radially movable leaf capable of moving between collapsed to deployed conditions). However, the solution is not so limited any instead greater or fewer than four leaves can be included, as needed or required.

In some embodiments, the expansion ring and leaf or leaves can be a monolithic structure. The expansion ring and leaf or leaves can also be formed from a memory alloy material such as nitinol.

In some embodiments, the expansion mechanism can include a plurality of expandable support elements that include potential energy stored in the collapsed state (e.g. the support elements may include biased bias elements or be memory shaped to expand a predetermined manner and release a predetermined amount of potential energy). The expandable support elements can be configured to urge the proximal end of the first radially expandable segment from the collapsed to the deployed state by releasing the potential energy of the expandable support elements.

In some embodiments, a porosity of the inner occlusive sack is greater than a porosity of the outer occlusive sack.

In some embodiments, distally translating the braid after the outer occlusive sack is formed causes an inner layer of the braid inside of the outer occlusive sack to radially expand inside the outer occlusive sack and form the inner occlusive sack. The inner layer of the braid can also be capable of radially expanding inside the outer occlusive sack while the outer occlusive sack is pushed against the aneurysm wall and aneurysm neck.

In some embodiments, a marker band can be included and in communication with the proximal end of the braid. The inner layer that radially expands inside the outer occlusive sack can also be formed by folding the proximal end over the marker band.

In some embodiments, wherein in the deployed state, the braid is detachable from a delivery system in the aneurysm.

In some embodiments, the delivery system can include a microcatheter and a delivery tube. The distal end of the delivery tube can be detachably connected to the proximal end of the braid. The delivery tube can be translatably disposable within the microcatheter. The delivery tube can also be capable of distally translating the braid within the microcatheter from the collapsed state to the deployed state.

In some embodiments, the outer occlusive sack can be a collapsible cage-like vaso-occlusive structure.

In some embodiments, the outer occlusive sack can include fewer wire segments than the inner occlusive sack.

In some embodiments, dimensions of interstices of the braid vary at the proximal end versus the distal end so that a porosity of the outer occlusive sack is less than a porosity of the inner occlusive sack.

In some embodiments, the braid can be included in a system or otherwise in communication with an imaging device capable of imaging the outer and/or inner occlusive sacks with respect to the aneurysm. An orientation of the outer and/or inner occlusive sacks can be adjustable by the braid being distally or proximally moved.

In some embodiments, an occlusive device for treating an aneurysm is provided. The device can include a braid being translatably disposable within a microcatheter from a collapsed state to a deployed state. The braid can include a distal end and a proximal end. In the deployed state, the braid can include an outer occlusive sack capable of pushing against an aneurysm wall of the aneurysm and sealing a neck of the aneurysm to deflect, divert, and/or slow a flow into the aneurysm, an inner occlusive sack disposed inside the outer occlusive sack, and an expansion mechanism disposed at the proximal end for urging formation of the outer and/or inner occlusive sacks in the deployed state.

In other embodiments, a method of occluding an aneurysm is disclosed. The method can include one or more of the following steps: positioning a radially expandable braid within a microcatheter, the braid being in a collapsed state within the microcatheter and comprising a distal end and a proximal end; attaching the proximal end of the braid to the distal end of a delivery tube; distally sliding the braid from the microcatheter, by the delivery tube, towards an aneurysm; urging a first radially expandable segment of the braid to form an outer occlusive sack by expanding an expansion mechanism of the braid, wherein the expansion mechanism is attached to the proximal end of the braid; laying the outer occlusive sack across a neck of the aneurysm; and further distally pushing the braid thereby expanding a second radially expandable segment inside of the outer occlusive sack while distally pushing the outer occlusive sack against the aneurysm wall and the neck of the aneurysm.

In certain embodiments, the method can include releasing the braid, including the outer and inner occlusive sacks, and withdrawing the delivery tube and the microcatheter from the aneurysm.

In certain embodiments, the expansion mechanism includes a plurality of radially spaced flexible elements, each flexible element capable of expanding from a collapsed condition in the microcatheter to an expanded condition in the deployed state to support a proximal portion of the outer occlusive sack. In this respect, the method can also include axially aligning the central axis of the expansion mechanism with a central axis of the first and second radially expandable segments; and radially spacing each flexible element about the central axis of the expansion mechanism.

In some embodiments, the method can include providing an expansion ring with an opening on or with the expansion mechanism; inserting a distal end of the braid through the opening; and folding the proximal end of the braid over the opening.

In some embodiments, the method can include radially spacing, about the expansion mechanism, at least four flexible elements that extend from an expansion ring, each flexible element being a radially movable leaf capable of moving between collapsed to deployed conditions.

In some embodiments, the method can include forming a monolithic structure from the expansion ring and the at least four flexible elements.

In some embodiments, the method can include forming a plurality of expandable support elements on the expansion mechanism that comprise potential energy stored in the collapsed state; and urging, by the expandable support elements, the proximal end of the first radially expandable segment from the collapsed to the deployed state by releasing the potential energy.

In some embodiments, the method can include forming the first radially expandable segment with a porosity lower than a porosity of the second radially expandable segment; positioning the first radially expandable segment adjacent or in communication with a neck of the aneurysm; and deflecting, diverting, and/or slowing a flow into the aneurysm.

Other aspects and features of the present disclosure will become apparent to those of ordinary skill in the art, upon reviewing the following detailed description in conjunction with the accompanying figures.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will now be made to the accompanying drawings, which are not necessarily drawn to scale.

FIG. 1A depicts an example occlusive device of this disclosure in a collapsed state.

FIG. 1B depicts an example occlusive device of this disclosure in a collapsed state within an example microcatheter.

FIG. 2A is a schematic side view of an exemplary delivery system with an occlusive device in a deployed state but not delivered to the aneurysm.

FIG. 2B is a schematic bottom view of an exemplary expansion mechanism and the outer occlusive sack of FIG. 2A with the delivery system removed.

FIG. 3A is an enlarged schematic side view of the delivery system and braid of FIGS. 1-2 as the occlusive device is being pushed into an example aneurysm;

FIG. 3B is an enlarged schematic side view of the delivery system and braid of FIGS. 1-2 as the occlusive device is being pushed into an example aneurysm;

FIG. 4A is an enlarged schematic side view of the delivery system and braid of FIGS. 1-2 as the occlusive device is being pushed into an example aneurysm;

FIG. 4B is an enlarged schematic side view of the delivery system and braid of FIGS. 1-2 after the occlusive device is deployed into an example aneurysm;

FIG. 5A is a perspective schematic view showing an exemplary delivery system for use with an example occlusive device;

FIG. 5B is a perspective schematic view of FIG. 5A but with partial cross-section of the delivery system and the occlusive device;

FIG. 6A is a perspective schematic view of FIGS. 5A-5B being deployed with partial cross-section of the delivery system and the occlusive device;

FIG. 6B is a perspective schematic view of FIGS. 5A-5B deployed with the exemplary delivery system detached from the occlusive device;

FIG. 7 depicts an example braid of this disclosure deployed in an example aneurysm;

FIG. 8A depicts an example prototype braid of this disclosure without an example expansion mechanism;

FIG. 8B depicts an example prototype braid of this disclosure without an example expansion mechanism;

FIG. 8C depicts an example prototype braid of this disclosure without an example expansion mechanism;

FIG. 8D depicts an example prototype braid of this disclosure without an example expansion mechanism; and

FIG. 9 is a flow diagram for a method of delivering an occlusive device

DETAILED DESCRIPTION

Although example embodiments of the disclosed technology are explained in detail herein, it is to be understood that other embodiments are contemplated. Accordingly, it is not intended that the disclosed technology be limited in its scope to the details of construction and arrangement of components set forth in the following description or illustrated in the drawings. The disclosed technology is capable of other embodiments and of being practiced or carried out in various ways.

It must also be noted that, as used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. By “comprising” or “containing” or “including” it is meant that at least the named compound, element, particle, or method step is present in the composition or article or method, but does not exclude the presence of other compounds, materials, particles, method steps, even if the other such compounds, material, particles, method steps have the same function as what is named.

In describing example embodiments, terminology will be resorted to for the sake of clarity. It is intended that each term contemplates its broadest meaning as understood by those skilled in the art and includes all technical equivalents that operate in a similar manner to accomplish a similar purpose. It is also to be understood that the mention of one or more steps of a method does not preclude the presence of additional method steps or intervening method steps between those steps expressly identified. Steps of a method may be performed in a different order than those described herein without departing from the scope of the disclosed technology. Similarly, it is also to be understood that the mention of one or more components in a device or system does not preclude the presence of additional components or intervening components between those components expressly identified.

As discussed herein, vasculature can be that of any “subject” or “patient” including of any human or animal. It should be appreciated that an animal may be a variety of any applicable type, including, but not limited thereto, mammal, veterinarian animal, livestock animal or pet type animal, etc. As an example, the animal may be a laboratory animal specifically selected to have certain characteristics similar to a human (e.g., rat, dog, pig, monkey, or the like). It should be appreciated that the subject may be any applicable human patient, for example.

As discussed herein, “operator” may include a doctor, surgeon, or any other individual or delivery instrumentation associated with delivery of a braid body to the vasculature of a subject.

Relatedly, flow diverters that are deployed across the aneurysm neck can alter the flow of blood into the aneurysm. An example flow diverter can be a braided device with relatively low porosity. Over time, the aneurysms can heal by sealing the aneurysm neck with a high rate of success. However, flow diversion technology is not without limitations. Challenges include placement of the devices intra-vascularly due to vessel morphology, vessel tortuosity, or braid malposition. In addition, patients receiving a flow diverter must be on anticoagulation medicine for an extended period to prevent vessel thrombosis. Intravascular devices also aim to cut circulation into the aneurysm while minimizing the amount of metal in the vessel and significantly cutting, or eliminating the need for coagulation medication. These types of devices may also be easier to track and/or deploy at the lesion site.

The occlusive device 1 disclosed herein addresses these and other drawbacks of previous approaches by using a single device to seal the aneurysm neck. Turning to FIG. 1A, an example occlusive device 1 of this disclosure is shown in a collapsed state prior to being arranged with a microcatheter 20. FIG. 1B depicts the occlusive device of FIG. 1A arranged in the collapsed state within the microcatheter 20. As shown, device 1 can include a braid 10 formed from multiple self-expanding multi-filament segments that can be formed from a mesh. For example, braid 10 can include a first radially expandable segment 12 associated with an outer occlusive sack and a second radially expandable segment 13 associated with an inner occlusive sack. Braid 10 can also have a distal end 14 associated with segment 12, a distal end 18 associated with segment 13, and a proximal end 16.

An expansion mechanism 9 can also be included disposed at or about proximal end 16 of braid 10. The expansion mechanism 9 can include one or more flexible support elements 7 that extend from or are attached to an expansion ring 5 with an opening 3. As shown, the flexible support elements 7 can be oriented to extend along the inner layer of braid 10 in both the collapsed and deployed states. Each flexible support element 7 of mechanism 9 can be elongate and extend at one or more depths into braid 10. Each element 7 of mechanism 9 can facilitate expansion of braid 10 to form sacks of segments 12 and/or 13, collectively with other flexible elements or individually. The flexible support element 7 is also referred to interchangeably herein as an elongate support element 7, a support element 7, or a flexible element 7.

The mesh of braid 10 can be defined by one or more mesh patterns, one or more discrete mesh portions, and/or one or more mesh openings defined by braided filaments. For example, the mesh of braid 10 can include a porosity region associated with an outer occlusive sack formed by braid 10 and another porosity region associated with an inner occlusive sack configured to expand and/or internally overlay the outer occlusive sack. The inner occlusive sack can have a higher porosity than the outer occlusive sack. For example, the mesh of braid 10 shown in FIGS. 1A and 1B can include a different porosity region associated with each of segments 12, 13.

Each of segments 12, 13 can be radially expandable and capable of being disposed inside microcatheter 20 in a collapsed state. Segment 12 can be an expandable, outer shell while segment 13 can be an inner, expandable shell. Segment 12 may expand and only partially file some of the aneurysm as shown and may form a “cup” like shape that within segment 13 can form and expand. Each of segments 12, 13 can be heat shaped to spherical, saddled, ellipsoid shaped, or any other shape, as shown in FIGS. 1A-2B. Though only segments 12, 13 are depicted, any number of segments could be included as needed or required. Each of segments 12, 13 can be capable of being moved from the collapsed state to a deployed state.

In practice, the porosity of segment 12 can permit the outer occlusive sack of segment 12 to take on many shapes prior to, during, or after delivery to aneurysm A. For example, the porosity of segment 12 can be relatively low to permit its sack to flexibly conform to a plurality of different shaped aneurysms. Segment 12 in this respect can have a porosity less than the porosity of segment 13 based on differing aperture sizes of the mesh. The porosities associated with segments 12, 13 and/or any other region or segment of braid 10 can also include a mesh with filaments having a different shape and/or pick count than the filaments in the other porosity regions.

The mesh of braid 10 can be comprised of a tube that is closed at one end (e.g. proximal end 16) and/or opened at opposite distal ends 14 and 18. Braid 10 can be made of several materials such as deposited thin films or of one single material. The mesh of braid 10 can include multiple wires, for example from 4 to 96 wires. The number of wires can be a factor in controlling material properties of the braid 10, including the porosity, shape in the deployed state, flexibility, stiffness, and the like. The combination of the one or more sacks internally overlaid with an outer occlusive sack can be considered when determining the number of wires of the mesh of braid 10 since one sack is inside the other. Further, the outer occlusive sack of segment 12 and/or the inner occlusive sack of segment 13 can be a collapsible cage-like vaso-occlusive structure.

The diameter of the braid 10, and the braid wire count can vary depending the diameter of the device needed to treat the aneurysm, and/or the desired porosity. For example, the distal end 14 of segment 12 can be an open end with a first diameter. The distal end 18 of segment 13 can be an open end with a second diameter that is less than the first diameter in the deployed state. The braid angle of the braid 10 can also be fixed, or vary along the length of braid 10 to create different porosity therealong. For example, to induce formation of the predetermined shape and strength of the occlusive sacks of segments 12 and 13, ends 14 and 18 may be more pliable than end 16, or vice versa, and other segments of braid 10 may vary from most pliable on or about end 14 and/or end 18 and less pliable on or about end 16. In some embodiments, ends 14, 18 can be looped as shown, which is particularly advantageous to ensure that the braid 10 is atraumatic when in contact with the dome of aneurysm A.

The number of wires, braid angle, patterns, or the like, can be used to define the porosities of segments 12, 13. The wires of braid 10 can be made from nitinol with interwoven platinum filaments for radiopacity, or Drawn Filled Tube (DFT) Nitinol with 10 to 40% Platinum. The wires can be made from a nickel-titanium alloy, cobalt chromium alloys, Stainless Steel, Tantalum, and/or other alloys, and/or any other suitable biocompatible materials, or combination of these materials. Also, these materials can be absorbable or non-absorbable by the patient over time. In this respect, the first porosity associated with segment 12 can be less than the second porosity associated with segment 13. Arranging segments 12, 13 in the deployed state, varying the braid properties, and/or positioning segment 12 adjacent or in communication with a neck of the aneurysm can induce a flow diverting effect. Material properties of segments 12, 13 can differ in other respects as well, as needed or required, including heat treatment or covering.

The apertures in the mesh of braid 10 can also create a substantially unitary frame work or mesh. Thus, the apertures may be of any size, shape, or porosity, and may be uniformly or randomly spaced throughout the wall of the mesh of braid 10. The apertures can provide the tubular element of braid 10 with flexibility and also assist in the transformation of the mesh from the collapsed state to the expanded, deployed state, and vice versa.

As shown in FIGS. 1B through FIG. 2B, a delivery system 40 can include the microcatheter 20 with a delivery tube 30 slideably disposed therein. The microcatheter 20 can be pre-placed at the level of the aneurysm neck and used to track the device to the aneurysm. The microcatheter 20 size can be selected in consideration of the size, shape, and directionality of the aneurysm or features through which the microcatheter 20 must pass to get to the treatment site. The microcatheter 20 may have a total usable length anywhere from 80 centimeters to 170 centimeters. The microcatheter 20 may have an inner diameter ID of anywhere between 0.015 and 0.032 inches. The outer diameter OD may also range in size and may narrow at either its proximal end or distal end. At its proximal end 26, the microcatheter 20 may be attached to a surgical device, and at its distal end 24 may be operable to be positioned at the neck of the aneurysm A. While the distal end 24 of the microcatheter 20 as shown contains the braid 10, the end 24 may be varied in shape and may curve at an angle.

Delivery tube 30 can be substantially elongate and can extend from the proximal 26 to the distal end 24 of microcatheter 20. Tube 30 can generally run along the inner lumen of microcatheter 20 and may leave a space between its outer surface and the internal surface of microcatheter 20. In turn, delivery tube 30 and microcatheter 30 may be axially aligned. System 40 can deliver braid 10 to a location of interest (e.g. a lesion site) using microcatheter 20. In certain embodiments, microcatheter 20 can be pre-placed at a level of the aneurysm neck and used to track the device 1 to the lesion, for example by tracking marker band 44 that can have radiopaque material. Delivery tube 30 can be in mechanical connection with braid 10 at locking portion 54. As shown more particularly below, locking portion 54 can comprise or be a pusher ring. Braid 10 may be attached to locking portion 54 by slidable attachment, permanent attachment (e.g. crimped, laser, ultrasonic weld, or other sources of heat, adhesive, or the like) or other attachment approaches. When delivery tube 30 is mechanically attached to braid 10 at locking portion 54, distally translating, sliding, or otherwise moving tube 30 towards the aneurysm A can cause braid 10 to begin moving from the collapsed state within microcatheter 20 to its deployed state external to microcatheter 20 with segments 12 and 13.

In the deployed state, some or all of braid 10 is distal of microcatheter 20 so that segments 12, 13 can radially expand. Braid 10 is particularly advantageous as it is capable of being collapsed within microcatheter 20 and also can form multiple occlusive sacks in the deployed state. The mesh of braid 10 can be configured with or without mechanism 9 so that as braid 10 is distally translated and its end 14 exits from within microcatheter 20, mechanism 9 can urge segment 12 to radially expand to form an outer occlusive sack of the first porosity. The outer occlusive sack of segment 12 can be formed as portions of flexible support elements 7 of mechanism 9 are distal of end 24 and end 14 of braid 10 slides away from end 24 of microcatheter 20. When flexible support elements 7 of mechanism 9 are no longer contained completely within microcatheter 20, they can then release potential energy stored therein and facilitate formation of the occlusive sacks of segments 12 and/or 13.

As braid 10 is further distally translated, segment 13 can begin to radially expand internal to the outer occlusive sack of segment 12. By radially expanding inside segment 12, segment 13 can form an inner occlusive sack with a porosity greater than the porosity of segment 12. As shown in FIG. 2A, the respective sacks of segments 12, 13 are formed now deployed and segment 13 is disposed internal to segment 12 but still connected to delivery tube 30 via locking portion 54. In FIG. 2A, the distal end 14 can form the outer layer of the outer occlusive sack of segment 12 while the proximal end 16 can form the outer layer of the inner occlusive sack of segment 13.

FIG. 2B is a schematic bottom view of an exemplary expansion mechanism 9 and the outer occlusive sack of segment 12 in a deployed state and delivery system 40 removed for purposes of clarity only. As shown, flexible elements 7 of mechanism 9 can be radially spaced about a central axis of the expansion mechanism, including a central axis of expansion ring 5 and/or opening 3. The expansion mechanism 9 can include a plurality of expandable, flexible support elements 7 capable of urging portions on or adjacent end 16 of braid 10 from the collapsed state in microcatheter 20 to the deployed state distal of microcatheter 20. Each element 7 of mechanism 9 can include potential energy stored in the collapsed state (e.g. the support elements 7 may include biased bias elements or be memory shaped to expand a predetermined manner and release a predetermined amount of potential energy). The expandable support elements 7 of mechanism 9 can be configured to urge the proximal end of the first radially expandable segment from the collapsed to the deployed state by releasing the potential energy of the expandable support elements 7.

In certain embodiments, the expansion mechanism 9 can include at least four radially spaced flexible support elements 7 that extend from a central portion of mechanism 9, such as expansion ring 5. When collapsed, the expansion mechanism 9 can be sized to fit through the neck of the aneurysm. When expanded and delivered to the aneurysm, the expansion mechanism 9 can be larger and block the neck. As shown in FIG. 2B, one or more flexible support elements 7 of mechanism 9 can be a radially movable leaf that can move between collapsed to deployed conditions. However, mechanism 9 is not so limited and instead greater or fewer than four leaves, or other elongate flexible support elements 7 of different structure but similar function, can be included as needed or required. The expansion ring 5 and leaf or leaves of mechanism 9 can also be a monolithic structure formed from a memory alloy material such as nitinol. The central axis of the expansion mechanism 9 can be axially aligned with a central axis of segments 12 and/or 13. Locking portion 54 may also be attached to mechanism 9 and/or aligned therewith.

As shown in FIG. 1B and FIG. 2B, end 16 can be disposed on or adjacent mechanism 9, marker band 44, and/or locking portion 54. To form or assemble braid 10 as shown in FIGS. 1A-2B, end 14 and/or 18 of braid 10 can be inserted through the opening 3 of mechanism 9 and then the proximal end 16 of braid 10 can be folded over the opening 3. In certain embodiments, the end 14 and/or 18 can also be inserted through marker band 44 until proximal end 16 is disposed on or adjacent to band 44 at locking portion 54. Locking portion 54 can then be connected to and/or folded over end 16. Braid 10 is not so limited and instead of being folded over, proximal end 16 can be operatively connected to mechanism 9, locking portion 54, or any other component thereof by sonic weld, mechanical attachment, or adhesive. Regardless of connection, the proximal end 16 being operatively connected to mechanism 7, locking portion 54, and/or band 44, can cause formation of an outer layer of the braid 10 associated with segment 12.

In practice, as shown in FIGS. 3A to 4B, the braid 10 can be pushed into the aneurysm A by the delivery tube 30 and be deployed with the lower porosity outer layer of segment 12 laying across the neck of the aneurysm A, and the inner layer of segment 13 can be expanding inside of the outer layer while pushing the outer layer in position against the aneurysm wall and/or aneurysm neck. In particular, FIGS. 3A to 4B depict an enlarged schematic side view of the delivery system 40 and braid 10 as the braid 10 is being pushed into an example aneurysm A. Prior to the arrangement of FIG. 3A, the braid 10 can be assembled with a delivery tube 30 and/or a microcatheter 20 in a collapsed state and thus disposed inside delivery system 40. In this respect, the delivery system 40 and braid 10 can be packaged as a portable kit or system. The assembly between microcatheter 20, delivery tube 30, and/or braid 10 can take place before being introduced into the vasculature. The delivery system 40 used with braid 10, which can include microcatheter 20 and delivery tube 30, can be selectively positioned at the lesion site and delivery tube 30 can begin distally translating braid 10 towards the aneurysm.

Turning to FIG. 3A, sack 12 has radially expanded towards the outer walls of aneurysm A while unexpanded portions (e.g. segment 13, end 16) of braid 10 continue to be mostly collapsed within microcatheter 20 and translated by delivery tube 30. Portions of braid 10 distal of end 24 can expand as braid 10 distally moves away from end 24 of catheter 20. When expanding from the collapsed state of FIG. 1B to the intermediary deployed state of FIG. 3A, segments 12 and 13 begin to radially expand to form their respective occlusive sacks within aneurysm A. Mechanism 9 is also depicted in FIG. 3A in a collapsed state completely contained within microcatheter 20. Ring 5 of mechanism 9 is shown in communication with end 16 while portions of elements 7 extend about segment 13 and in communication with segment 12 on or about end 16. In this respect, as braid 10 distally translates, segment 12 and/or segment 13 can be urged by elements 7 of mechanism 9 to form the occlusive sacks of this disclosure.

As shown in the transitional state of FIG. 3A, the sack of segment 12 can be generally spherical shape internal to aneurysm A while segment 13 remains mostly collapsed and stored within microcatheter 20. However, the portion of segment 13 distal of end 24 begun to radially expand within segment 12.

In FIG. 3B, the delivery tube 30 has distally slid braid 10 deeper into aneurysm A so that the outer surface of segment 12 has moved closer to contacting dome D. Locking portion 54 is depicted proximate or adjacent end 24 of microcatheter 20 so that all portions of braid 10, including mechanism 9, are distal thereof and external of microcatheter 20. As a result, elements 7 of mechanism 9 are shown urging expansion of segment 12 on or about end 16 to radially expand and form the outer occlusive sack shown filing the aneurysm A. It is understood that the outer surface of braid 10 can be made from nitinol with interwoven platinum filaments for radiopacity. Delivery tube 30 may be driven between FIGS. 3A and 3B by a hypotube from its proximal end 36 by an operator or the like. Microcatheter 20 may remain relatively stationary or fixed while delivery tube 30 can be seen distally translating braid 10 towards and through the neck of aneurysm A.

Braid 10 can include a pre-weakened or transition portion 19 (e.g., depicted in FIGS. 1A-1B) so that as braid 10 and delivery tube 30 are distally translated away from microcatheter 20 and deeper into aneurysm A, elements 7 of mechanism can urge segments 12 to expand and portion 19 can facilitate initiation of the radial expansion of segment 13 inside segment 12. For example, translation of braid 10 a first predetermined distance can cause segment 12 to radially expand to form its outer occlusive sack. Further translating braid a second predetermined distance into aneurysm A, as is shown in FIG. 3B can cause the inner occlusive sack of segment 13 to form inside of the outer occlusive sack. In certain embodiments, portion 19 can initiate radial expansion of segment 13 inside segment 12.

In FIG. 4A, the delivery tube 30 is distally translated deeper into aneurysm A. Moving between FIGS. 3A to 4A, it is shown that distally translating the braid 10, by the delivery tube 30, deeper into aneurysm A can further cause elements 7 of mechanism 9 to expand more and urge segment 12 to also additionally radially expand and press against the aneurysm wall. Further distal translation also can essentially cause locking portion 54 to make greater the expansion angle of segment 7 and push ring 5 of mechanism 9 towards the aneurysm neck. In turn, mechanism 9 is essentially tucked into braid segment 13 thereby flattening or otherwise rendering more spherical the sack of segment 12. In certain embodiments, the widening of segment 12 between FIGS. 3A and 4A can cause end 14 to slide proximally back towards end 24 of microcatheter while segment 13 continues to expand radially.

As also seen moving between FIGS. 3A to 4A, the junction between end 16 of braid 10, locking portion 54, mechanism 9, and delivery tube 30 can move from within microcatheter 20 in the collapsed state to completely within aneurysm A in the deployed state. Once braid 10, including segments 12 and 13, are selectively positioned and arranged to the desired condition (e.g. braid 10 has been translated distally to expand segments 12, 13 to form the outer and inner sacks), braid 10 can be detached from the delivery tube 30 as shown in FIG. 4B. In other words, as the braid 10 is distally translated towards the dome of the aneurysm A, segments 12, 13 can expand and be used to radially expand to support the aneurysm wall in a manner that is easy, efficient, and avoids risks of rupture.

Once expanded and positioned, delivery tube 30 can be proximally translated back into microcatheter 20 and retracted from the braid 10 and aneurysm A. In particular, FIG. 4B shows an example arrangement of braid 10 in its expanded state and the inner and outer sacks of segments 13 and 12, respectively, completely formed with delivery tube 30 having detached from locking portion 54. Expanding segments 12, 13 and positioning mechanism 9 into the braid 10 is particularly advantageous as it can prevent braid 10 from creating a protrusion that would otherwise extend into the parent vessel. Instead, any such protrusion can now be tucked into segment 12 and/or 13 of braid 10. Arranging braid 10 in this manner across the neck of the aneurysm while also varying the porosity of segments 12, 13 can also create a flow diversion essentially inside of the sacks of braid 10. FIG. 4B merely shows example spherical sacks of segments 12, 13 fully formed in a manner sufficient to occlude aneurysm. However, if either sack of segments 12, 13 is not precisely positioned or needs to be reset or adjusted within aneurysm A for safe occlusion without risk of rupture, braid 10 can be retracted back into microcatheter 20 by proximally withdrawing delivery tube 30 while still attached to braid 10.

FIGS. 5A to 6B generally illustrate example attachment and delivery between delivery tube 30 and braid 10 for deploying and detaching braid 10 in aneurysm A. The embodiments of FIGS. 5A to 6B is merely one way that delivery tube 30 and braid 10 may be attached at end 34 and any number of attachment means are contemplated as needed or required. The delivery tube 30 as shown can have a lumen extending from a proximal end 36 to a distal, delivery end 34. FIG. 5A illustrates braid 10 engaged with the locking member 52 and loop wire 58 locked into the locking portion 54. The opening 60 of the loop wire 58 can be placed through the locking portion 54. The locking portion 54 preferably takes the form of a small diameter elongate filament, however, other forms such as wires or tubular structures are also suitable. While the locking portion 54 is preferably formed of nitinol, other metals and materials such as stainless steel, PTFE, nylon, ceramic or glass fiber and composites may also be suitable. Locking member 52, in one example, may be an elongated retractable fiber that may extend between ends 24 and 26 of the microcatheter 20. Locking member 52 preferably takes the form of a small diameter elongate filament, however, other forms such as wires or tubular structures are also suitable. While the locking member 52 is preferably formed of nitinol, other metals and materials such as stainless steel, PTFE, nylon, ceramic or glass fiber and composites may also be suitable. When the locking member 52 is put through the opening 60 the braid 10 is now secure. It is understood that delivery tube 30 may include a compressible portion 38 disposed between its ends 34 and 36.

The compressible portion 38 can allow the delivery tube 30 to bend and/or flex. Such flexibility can assist tracking the braid 10 through the microcatheter 20 and the tortuous path through the vasculature. The compressible portion 38 can be formed with interference spiral cuts that can allow for gaps to permit bending but in one example, do not act as a spiral-cut spring. Compressible portion 38 can be axially adjustable between an elongated condition and a compressed condition. However, any other arrangement allowing axial adjustment (e.g., a wound wire or spiral ribbon) can also be suitable for use with detachment systems according to the present disclosure). The compressible portion 38 can be in the elongated condition at rest and automatically or resiliently returns to the elongated condition from a compressed condition, unless otherwise constrained. The function of the compressible portion 38 is described in greater detail herein.

A force F was previously applied to place the delivery tube 30 in a compressed state. FIG. 5B illustrates the locking member 52 being drawn proximally to begin the release sequence for braid 10. FIG. 6A illustrates the instant the locking member 52 exits the opening 60 and is pulled free of the loop wire 58. The distal end 62 of the loop wire 58 falls away/returns to its preformed shape and exits the locking portion 54. As can be seen, there is now nothing holding the braid 10 to the delivery tube 30. FIG. 6B illustrates the end of the release sequence. Here, the compressible portion 38 of the delivery tube 30 has expanded/returned to its original shape and “sprung” forward. An elastic force E is imparted by the distal end 34 of the delivery tube 30 to the braid 10 to “push” it away to insure a clean separation and delivery of the braid 10 to the aneurysm A. It is to be understood that the delivery scheme described in FIGS. 6A-7B are merely example approaches to delivery of braid 10.

FIG. 7 depicts an example braid 10 of this disclosure deployed in an example aneurysm A.

FIGS. 8A-8D depict example prototype braids of this disclosure with varying braid properties. These prototypes are strictly for illustrative purposes.

FIG. 9 is a flow diagram for a method 900 of delivering an occlusive device to the aneurysm. Step 905 includes positioning a radially expandable braid within a microcatheter, the braid being in a collapsed state within the microcatheter and comprising a distal end and a proximal end. Step 910 includes attaching the proximal end of the braid to the distal end of a delivery tube. Step 915 includes distally sliding the braid from the microcatheter, by the delivery tube, towards an aneurysm. Step 920 includes urging a first radially expandable segment of the braid to form an outer occlusive sack by expanding an expansion mechanism of the braid expands, the expansion mechanism attached to the proximal end of the braid, the outer occlusive sack being operable to lay across a neck of the aneurysm. Step 925 further distally pushing the braid thereby expanding a second radially expandable segment inside of the outer occlusive sack while distally pushing the outer occlusive sack against the aneurysm wall and the neck of the aneurysm. Step 930 releasing the braid, including the outer and inner occlusive sacks, and withdrawing the delivery tube and the microcatheter from the aneurysm. The outer occlusive sack can form upon or as the distal end of the braid is moved distally from the microcatheter and in communication with a dome of the aneurysm.

In certain embodiments of method 900, the expansion mechanism can include a plurality of radially spaced flexible elements, each flexible element capable of expanding from a collapsed condition in the microcatheter to an expanded condition in the deployed state to support a proximal portion of the outer occlusive sack. In this respect, the method 900 can also include axially aligning the central axis of the expansion mechanism with a central axis of the first and second radially expandable segments; and radially spacing each flexible element about the central axis of the expansion mechanism.

The method 900 can also include providing an expansion ring with an opening on or with the expansion mechanism; inserting a distal end of the braid through the opening; and folding the proximal end of the braid over the opening. The method 900 can also include radially spacing, about the expansion mechanism, at least four flexible elements that extend from an expansion ring, each flexible element being a radially movable leaf capable of moving between collapsed to deployed conditions. The method 900 can also include forming a monolithic structure from the expansion ring and the at least four flexible elements. The method 900 can also include forming a plurality of expandable support elements on the expansion mechanism that comprise potential energy stored in the collapsed state; and urging, by the expandable support elements, the proximal end of the first radially expandable segment from the collapsed to the deployed state by releasing the potential energy. The method 900 can also include forming the first radially expandable segment with a porosity lower than a porosity of the second radially expandable segment; positioning the first radially expandable segment adjacent or in communication with a neck of the aneurysm; and inducing a flow diverting effect across the neck of the aneurysm when the inner occlusive sack is formed inside the outer occlusive sack.

It is understood that variations of the braid 10 can include various materials such as stainless steel, bio absorbable materials, and polymers. Braid 10, including any specific portions such as any breaks, varying regions of differing porosities, and occlusive sacks, can be heat set to various configurations such as spherical, oblong, saddle shaped, or the like, for the purpose of shaping the outer and/or inner sack to better match the aneurysm morphology. In addition, the braid 10 can be heat shaped to include weak points to facility the radial expansion of the occlusive sacks. Further, interstices of braid 10 that form the sacks can vary, or be selectively designed, in size or shape along its length depending on how much braid 10 is caused to radially expand as delivery tube 30 is distally moved.

It is understood that the braid 10 can also be included in a system or otherwise in communication with an imaging device capable of imaging the outer and/or inner occlusive sacks of segments 12 and 13 with respect to the aneurysm. An orientation of the outer and/or inner occlusive sacks can be adjustable by the braid 10 being distally or proximally moved with respect to the aneurysm and monitored precisely by the imaging device.

The specific configurations, choice of materials and the size and shape of various elements can be varied according to particular design specifications or constraints requiring a system or method constructed according to the principles of the disclosed technology. Such changes are intended to be embraced within the scope of the disclosed technology. The presently disclosed embodiments, therefore, are considered in all respects to be illustrative and not restrictive. It will therefore be apparent from the foregoing that while particular forms of the disclosure have been illustrated and described, various modifications can be made without departing from the spirit and scope of the disclosure and all changes that come within the meaning and range of equivalents thereof are intended to be embraced therein.

Claims

1. A braid for treating an aneurysm, the braid comprising: a first radially expandable segment capable of radially expanding to form an outer occlusive sack in the aneurysm configured to seal a neck of the aneurysm as the braid is being moved distally toward the aneurysm;a second radially expandable segment capable of radially independently expanding inside the outer occlusive sack as the outer occlusive sack is forming to form an inner occlusive sack in the outer occlusive sack as the braid is being moved further distally in the aneurysm; wherein proximal ends of each segment are aligned with each other and distal ends of each segment are positioned opposite the proximal ends of each segment; anda plurality of radially flexible elements positioned at the proximal end of the first radially expandable segment, wherein each flexible element is capable of expanding from a collapsed condition to an expanded condition to support a proximal portion of the outer occlusive sack, and wherein each flexible element comprises a radially movable leaf.

2. The braid of claim 1, the plurality of radially flexible elements arranged surrounding an opening between the radially flexible elements, wherein a distal end of the braid is insertable through the opening.

3. The braid of claim 2, wherein a proximal end of the braid is foldable over the opening.

4. The braid of claim 2, wherein each radially flexible element is evenly radially spaced about a central axis aligned with the opening, the central axis being axially aligned with a central axis of the first and second radially expandable segments.

5. The braid of claim 1, wherein at least four radially flexible elements are comprised in the plurality of radially flexible elements that extend from an expansion ring, each flexible element capable of moving between collapsed to deployed conditions.

6. The braid of claim 5, wherein the expansion ring is formed from a memory alloy material.

7. The braid of claim 1, wherein the plurality of radially flexible elements is attached to and configured to urge the proximal end of the first radially expandable segment from a collapsed to a deployed state by releasing potential energy of the radially flexible elements.

8. The braid of claim 1, the inner occlusive sack comprising a porosity greater than a porosity of the outer occlusive sack.

9. The braid of claim 1, wherein the inner occlusive sack of the braid is capable of radially expanding inside the outer occlusive sack while the outer occlusive sack is pushed against the aneurysm wall.

10. The braid of claim 1, further comprising a marker band in communication with a proximal end of the braid.

11. The braid of claim 10, wherein the inner occlusive sack of the braid radially expands inside the outer occlusive sack by folding the proximal end of the braid over the marker band.

12. The braid of claim 1, the braid being detachable from a delivery system in the aneurysm, the delivery system comprising a delivery tube comprising a distal end and a proximal end, the distal end of the delivery tube being detachably connected to a proximal end of the braid.

13. A method of occluding an aneurysm, comprising: distally moving a braid towards the aneurysm to form an outer occlusive sack of a first radially expandable mesh segment of the braid by expanding a plurality of radially flexible elements attached to a proximal end of the braid; anddistally moving the braid in the aneurysm as the outer occlusive sack is forming thereby expanding a second radially expandable mesh segment inside of the outer occlusive sack to form an inner occlusive sack;wherein proximal ends of each segment are aligned with each other and distal ends of each segment are positioned opposite the proximal ends of each segment, andwherein each radially flexible element comprises a radially movable leaf.

14. The method of claim 13, further comprising: supporting a proximal portion of the outer occlusive sack, by the plurality of radially flexible elements; andradially spacing each radially flexible element about a central axis of the braid.

15. The method of claim 13, further comprising: inserting a distal end of the braid through an opening defined between the radially flexible elements; andfolding the proximal end of the braid over the opening.

16. The method of claim 13, further comprising: extending the radially flexible elements from an expansion ring.

17. The method of claim 13, further comprising: urging, by the plurality of radially spaced flexible elements attached to the proximal end of the first radially expandable mesh segment, the proximal end of the first radially expandable mesh segment to form the outer occlusive sack.

18. The method of claim 13, further comprising: forming the first radially expandable mesh segment with a porosity lower than a porosity of the second radially expandable segment.

19. The method of claim 13, further comprising: positioning the first radially expandable mesh segment adjacent or in communication with a neck of the aneurysm.