Patent ID: 12251110

DETAILED DESCRIPTION

Methods for treating intracranial aneurysms in accordance with at least some embodiments of the present technology include positioning an expandable occlusive member within the aneurysm and introducing an embolic element between the occlusive member and an aneurysm wall. Introduction of the embolic element both fills space within the aneurysm cavity and deforms the occlusive member from a first expanded state to a second expanded state to fortify the occlusive member at the neck of the aneurysm. Deformation of the occlusive member from a first expanded state to a second expanded state provides the additional advantage of giving visual confirmation to the physician that the delivered amount of embolic element sufficiently fills the aneurysm cavity. In addition to providing a structural support and anchor for the embolic element, the occlusive member provides a scaffold for tissue remodeling and diverts blood flow from the aneurysm. Moreover, the embolic element exerts a substantially uniform pressure on the occlusive member towards the neck of the aneurysm, thereby pressing the portions of the occlusive member positioned adjacent the neck against the inner surface of the aneurysm wall such that the occlusive member forms a complete and stable seal at the neck.

Once the occlusive member has deployed within the aneurysm and the embolic element has been delivered, the occlusive member may be detached from the delivery assembly. Suitable detachment mechanisms must be as small as possible so as to be guided through the fine bore of the catheter to the treatment site, while on the other hand they must securely and reliably produce detachment of the intrasaccular implant. Absent a reliable detachment of the intrasaccular implant, withdrawal of the delivery conduit and catheter may cause unintended removal of the occlusive member from the cavity to be occluded and thus injure and/or rupture of the wall of the cavity or vessel. In some embodiments, an electrolytic detachment mechanism as described herein can be used to facilitate reliable, controlled detachment of the occlusive member.

The occlusive member can be implanted in body cavities or blood vessels. In addition to the occlusive member, the treatment system can comprise a voltage source, a cathode, a delivery conduit, and a catheter. The occlusive member and the delivery conduit can be coupled together such that both can be slid in the catheter in the longitudinal direction. For example, the occlusive member can be coupled to a distal portion of the conduit, and the conduit can include a detachment zone configured to be electrolytically severed. In some embodiments, the conduit can be adapted to serve as an anode, such that a portion of the conduit is designed to be electrolytically corroded at one or more points so that while in contact with a body fluid, and the occlusive member may be released from the conduit. The delivery conduit can be configured to pass one or more embolic elements therethrough for intrasaccular delivery. The embolic element may be passed through the conduit and delivered to the treatment site. Once the occlusive member and any embolic elements are deployed, current can be applied to the conduit to electrolytically corrode the conduit at the detachment zone. After the conduit has been severed at the detachment zone, the conduit can be retracted, and the occlusive member may remain in position at the treatment site. In some embodiments, an inner liner and/or an outer sheath extend along at least a portion of the length of the conduit. The outer sheath can include a gap or opening that is aligned with the detachment zone such that the detachment zone of the conduit is exposed to bodily fluids while at the treatment site.

Specific details of systems, devices, and methods for treating intracranial aneurysms in accordance with embodiments of the present technology are described herein with reference toFIGS.1A-8C. Although these systems, devices, and methods may be described herein primarily or entirely in the context of treating saccular intracranial aneurysms, other contexts are within the scope of the present technology. For example, suitable features of described systems, devices, and methods for treating saccular intracranial aneurysms can be implemented in the context of treating non-saccular intracranial aneurysms, abdominal aortic aneurysms, thoracic aortic aneurysms, renal artery aneurysms, arteriovenous malformations, tumors (e.g. via occlusion of vessel(s) feeding a tumor), perivascular leaks, varicose veins (e.g. via occlusion of one or more truncal veins such as the great saphenous vein), hemorrhoids, and sealing endoleaks adjacent to artificial heart valves, covered stents, and abdominal aortic aneurysm devices among other examples. Furthermore, it should be understood, in general, that other systems, devices, and methods in addition to those disclosed herein are within the scope of the present disclosure. For example, systems, devices, and methods in accordance with embodiments of the present technology can have different and/or additional configurations, components, procedures, etc. than those disclosed herein. Moreover, systems, devices, and methods in accordance with embodiments of the present disclosure can be without one or more of the configurations, components, procedures, etc. disclosed herein without deviating from the present technology.

I. Overview of Systems of the Present Technology

FIG.1Aillustrates a view of a system10for treating intracranial aneurysms according to one or more embodiments of the present technology. As shown inFIG.1A, the system10comprises a treatment system100and an embolic kit200for use with one or more components of the treatment system100. The treatment system100may comprise an occlusive member102(shown in an expanded state) detachably coupled to a delivery system, and the delivery system may be configured to intravascularly position the occlusive member102within an aneurysm. The embolic kit200may comprise one or more substances or devices that alone or in combination form an embolic element that is configured to co-occupy the internal volume of the aneurysm with the occlusive member102. In some embodiments, the treatment system100may be configured to deliver the embolic element (and/or one or more precursors thereof) to the aneurysm. Additionally or alternatively, the system10may include a separate delivery system (not shown) for delivering the embolic element (and/or one or more precursors thereof) to the aneurysm cavity.

As shown inFIG.1A, the treatment system100has a proximal portion100aconfigured to be extracorporeally positioned during treatment and a distal portion100bconfigured to be intravascularly positioned within a blood vessel (such as an intracranial blood vessel) at a treatment site at or proximate an aneurysm. The treatment system100may include a handle103at the proximal portion100a, the occlusive member102at the distal portion100b, and a plurality of elongated shafts or members extending between the proximal and distal portions100aand100b. In some embodiments, such as that shown inFIG.1A, the treatment system100may include a first elongated shaft109(such as a guide catheter or balloon guide catheter), a second elongated shaft108(such as a microcatheter) configured to be slidably disposed within a lumen of the first elongated shaft109, and an elongated member106configured to be slidably disposed within a lumen of the second elongated shaft108. In some embodiments, the treatment system100does not include the first elongated shaft109and only includes the second elongated shaft108.

FIG.1Bis an enlarged view of the distal portion100bof the treatment system100. Referring toFIGS.1A and1Btogether, the occlusive member102may be detachably coupled to a distal portion of the elongated member106. For example, the elongated member106may include a first coupler112, and the occlusive member102may include a second coupler114configured to detachably couple with the first coupler112. In some embodiments, the couplers112,114can take the form of an electrolytic detachment mechanism, for example as described in more detail below with respect toFIGS.4-8C. The treatment system100may further comprise a conduit116extending from the handle103(for example, via port110) distally to the distal portion100bof the treatment system100. The conduit116is configured to deliver the embolic element (and/or one or more precursors thereof) through one or more components of the delivery system (e.g., the first or second elongated shafts109,108, the elongated member106, etc.) to a position at the exterior of the occlusive member102. As such, the embolic element may be positioned between the occlusive member102and an inner wall of the aneurysm cavity, as described in greater detail below. In some embodiments, the elongated member106serves as the conduit116.

According to some embodiments, the second elongated shaft108is generally constructed to track over a conventional guidewire in the cervical anatomy and into the cerebral vessels associated with the brain and may also be chosen according to several standard designs that are generally available. Accordingly, the second elongated shaft108can have a length that is at least 125 cm long, and more particularly may be between about 125 cm and about 175 cm long. In some embodiments, the second elongated shaft108may have an inner diameter of about 0.015 inches (0.0381 cm), 0.017 inches (0.043 cm), about 0.021 inches (0.053 cm), or about 0.027 inches (0.069 cm). Other designs and dimensions are contemplated.

The elongated member106can be movable within the first and/or second elongated shafts109,108to position the occlusive member102at a desired location. The elongated member106can be sufficiently flexible to allow manipulation, e.g., advancement and/or retraction, of the occlusive member102through tortuous passages. Tortuous passages can include, for example, catheter lumens, microcatheter lumens, blood vessels, urinary tracts, biliary tracts, and airways. The elongated member106can be formed of any material and in any dimensions suitable for the task(s) for which the system is to be employed. In some embodiments, the elongated member106can comprise an elongated tubular member having a lumen therein, for example a conduit. In some embodiments, the elongated member106may comprise any other suitable form such as a solid metal wire, an elongated tubular shaft, or any combination thereof.

In some embodiments, the elongated member106can comprise stainless steel, nitinol, or other metal or alloy. In some embodiments, the elongated member106can be surrounded over some or all of its length by a coating, such as, for example, polytetrafluoroethylene. In some examples, the elongated member106can be a hypotube or other conductive tubular member, and can include an outer insulative sheath and/or an inner insulative liner extending along a length of the elongated member106. The elongated member106may have a diameter that is generally constant along its length, or the elongated member106may have a diameter that tapers radially inwardly, along at least a portion of its length, as it extends in a distal direction.

A power supply113may be coupled to a proximal portion of the elongated shaft108, which can take the form of a conductive wire. The power supply113may also be coupled to a proximal portion of a handle or to the patient. A current can flow from the power supply113, to a detachment zone at or near the occlusive member102, and to a return path via the first elongated shaft109, the second elongated shaft108, and/or another structure extending near the detachment zone. Alternatively, the current from the detachment zone may flow to the patient, and subsequently to ground or to the power supply113. Power supply113, for example, may be a direct current power supply, an alternating current power supply, or a power supply switchable between a direct current and an alternating current. A positive terminal of a direct current power supply, as shown inFIG.1, may be coupled to the proximal portion of the elongated shaft108,111and a negative terminal of a direct current power supply may be coupled to the proximal portion of the handle. Power supply113may provide a current through the treatment system100to initiate an electrolytic process during use of the assembly in a fluid medium such as a bloodstream, which may be used as an electrolyte. A power supply, such as an alternating or direct current power supply, may additionally be used to initiate an electrothrombosis process.

A. Selected Examples of Occlusive Members

FIG.1Cis a sectioned view of the occlusive member102, shown in an expanded state and detached from the treatment system100. Referring toFIGS.1B and1C, the occlusive member102may comprise an expandable element having a low-profile or constrained state while positioned within a catheter (such as the second elongated shaft108) for delivery to the aneurysm and an expanded state in which the expandable element is configured to be positioned within an aneurysm (such as a cerebral aneurysm).

According to some embodiments, the occlusive member102may comprise a mesh101formed of a plurality of braided filaments that have been heat-set to assume a predetermined shape enclosing an interior volume130when the mesh101is in an expanded, unconstrained state. Example shapes include a globular shape, such as a sphere, a prolate spheroid, an oblate spheroid, and others. As depicted inFIG.1C, the mesh101may have inner and outer layers122,124that have proximal ends fixed relative to one another at the second coupler114and meet distally at a distal fold128surrounding an aperture126. While the inner and outer layers122,124are depicted spaced apart from one another along their lengths, the inner and outer layers122,124may be in contact with one another along all or a portion of their lengths. For example, the inner layer122may press radially outwardly against the outer layer124. In some embodiments, the occlusive member102may be formed of a single layer or mesh or braid.

In some embodiments, the inner and outer layers122,124have their distal ends fixed relative to one another at a distal coupler and meet proximally at a proximal fold surrounding an aperture. In any case, in some embodiments the conduit116may be configured to be slidably positioned through some or all of the second coupler114, the interior volume130of the expanded mesh101, and the opening126.

The inner and outer layers122and124may conform to one another at the distal portion (for example as shown inFIG.1C) to form a curved distal surface. For example, at least at the distal portion of the occlusive member102, the inner and outer layers122and124may extend distally and radially inwardly, towards the aperture126. In some embodiments, the outer and/or inner layers122and124extend distally and radially outwardly from the second coupler114, then extend distally and radially inwardly up to a distal terminus of the occlusive member102(e.g., the fold128). The occlusive member102and/or layers thereof may be curved along its entire length, or may have one or more generally straight portions. In some embodiments, the curved surface transitions to a flat or substantially flat, distal-most surface that surrounds the aperture126. In some embodiments, the curved surface transitions to a distal-most surface that surrounds the aperture126and has a radius of curvature that is greater than the average radius of curvature of the rest of the occlusive member102. Having a flat or substantially flat distal surface, or a distal surface with a radius of curvature that is greater than the average radius of curvature of the rest of the occlusive member102, may be beneficial for delivering the embolic element230in that it creates a small gap between the distal surface of the occlusive member102and the dome of the aneurysm A (see, for example,FIG.3B). In some embodiments, the surface of the occlusive member102surrounding the aperture126is curved and/or has generally the same radius of curvature as the remainder of the occlusive member102.

The inner layer124may have a shape that substantially conforms to the shape of the outer layer124, or the inner and outer layers122,124may have different shapes. For example, as shown inFIG.1D, the inner layer122may have a diameter or cross-sectional dimension that is less than the outer layer124. Such a configuration may be beneficial in that the embolic element230experiences less resistance, at least initially, when pushing the distal wall of the occlusion member102downwardly towards the neck (as described in greater detail below).

In any case, both the proximal portion and the distal portion of the mesh101can form generally closed surfaces. However, unlike at the proximal portion of the mesh101, the portion of the filaments at or near the fold128at the distal portion of the mesh101can move relative to one another. As such, the distal portion of the mesh101has both the properties of a closed end and also some properties of an open end (like a traditional stent), such as some freedom of movement of the distal-most portions of the filaments and an opening through which the conduit116, a guidewire, guidetube, or other elongated member may pass through.

In some embodiments, each of the plurality of filaments have a first end positioned at the proximal portion of the mesh101and a second end also positioned at the proximal portion of the mesh101. Each of the filaments may extend from its corresponding first end distally along the body of the mesh101to the fold128, invert, then extend proximally along the mesh body to its corresponding second end at the proximal portion of the mesh101. As such, each of the plurality of filaments have a first length that forms the inner layer122of the mesh101, a second length that forms the outer layer124of the mesh101, and both first and second ends fixed at the proximal portion of the mesh101. In some embodiments, the occlusive member102may comprise a mesh formed of a single layer, or a mesh formed of three or more layers.

In some embodiments, the distal end surface of the mesh101is completely closed (i.e., does not include an aperture). In some embodiments the filaments are fixed relative to the at both the proximal and distal ends of the occlusive member102.

The mesh101may be formed of metal wires, polymer wires, or both, and the wires may have shape memory and/or superelastic properties. The mesh101may be formed of 24, 32, 36, 48, 64, 72, 96, 128, or 144 filaments. The mesh101may be formed of a range of filament or wire sizes, such as wires having a diameter of from about 0.0004 inches to about 0.0020 inches, or of from about 0.0009 inches to about 0.0012 inches. In some embodiments, each of the wires or filaments have a diameter of about 0.0004 inches, about 0.0005 inches, about 0.0006 inches, about 0.0007 inches, about 0.0008 inches, about 0.0009 inches, about 0.001 inches, about 0.0011 inches, about 0.0012 inches, about 0.0013 inches, about 0.0014 inches, about 0.0015 inches, about 0.0016 inches, about 0.0017 inches, about 0.0018 inches, about 0.0019 inches, or about 0.0020 inches. In some embodiments, all of the filaments of the braided mesh101may have the same diameter. For example, in some embodiments, all of the filaments have a diameter of about 0.001 inches. In some embodiments, some of the filaments may have different cross-sectional diameters. For example, some of the filaments may have a slightly thicker diameter to impart additional strength to the braided layers. In some embodiments, some of the filaments can have a diameter of about 0.001 inches, and some of the filaments can have a diameter of greater than 0.001 inches. The thicker filaments may impart greater strength to the braid without significantly increasing the device delivery profile, with the thinner wires offering some strength while filling-out the braid matrix density.

The occlusive member102can have different shapes and sizes in an expanded, unconstrained state. For example, the occlusive member102may have a bullet shape, a barrel-shape, an egg shape, a dreidel shape, a bowl shape, a disc shape, a cylindrical or substantially cylindrical shape, a barrel shape, a chalice shape, etc.

B. Selected Examples of Embolic Kits

The embolic kit200may include one or more precursors for creation of a liquid embolic. For example, the embolic kit200may include a first container202containing a first precursor material203(shown schematically), a second container204containing a second precursor material205(also shown schematically), and a mixing device206suitable for mixing the first and second precursor materials203,205. The mixing device206can include mixing syringes208(individually identified as mixing syringes208a,208b) and a coupler210extending between respective exit ports (not shown) of the mixing syringes208. The mixing syringes208a,208beach include a plunger212and a barrel214in which the plunger212is slidably received.

The embolic kit200can further include an injection syringe216configured to receive a mixture of the first and second precursor materials203,205and deliver the mixture to a proximal portion100bof the treatment assembly100. The injection syringe216can include a barrel220, an exit port222at one end of the barrel220, and a plunger224slidably received within the barrel220via an opposite end of the barrel220. The handle103of the treatment system100may have a coupler configured to form a secure fluidic connection between the lumen and the exit port222of the injection syringe216.

The first and second precursor materials203,205can include a biopolymer and a chemical crosslinking agent, respectively. The chemical crosslinking agent can be selected to form covalent crosslinks between chains of the biopolymer. In some embodiments, the biopolymer of the first precursor material203includes chitosan or a derivative or analog thereof, and the chemical crosslinking agent of the second precursor material205includes genipin or a derivative or analog thereof. Other suitable crosslinking agents for use with chitosan include glutaraldehyde, functionalized polyethylene glycol, and derivatives and analogs thereof. In other embodiments, the biopolymer of the first precursor material203can include collagen or a derivative or analog thereof, and the chemical crosslinking agent of the second precursor material205can include hexamethylene diisocyanate or a derivative or analog thereof. Alternatively or in addition, genipin or a derivative or analog thereof can be used as a chemical crosslinking agent for a collagen-based biopolymer. In still other embodiments, the biopolymer of the first precursor material203and the chemical crosslinking agent of the second precursor material205can include other suitable compounds alone or in combination.

Mixing the biopolymer of the first precursor material203and the chemical crosslinking agent of the second precursor material205can initiate chemical crosslinking of the biopolymer. After the first and second precursor materials203,205are mixed, chemical crosslinking of the biopolymer occurs for enough time to allow the resulting embolic element230be delivered to the aneurysm before becoming too viscous to move through the lumen of the conduit116. In addition, the period of time during which chemical crosslinking of the biopolymer occurs can be short enough to reach a target deployed viscosity within a reasonable time (e.g., in the range of 10-60 minutes; or at most 40 minutes, 30 minutes, 20 minutes, or 10 minutes) after delivery. The target deployed viscosity can be high enough to cause an agglomeration of the embolic element230to remain within the internal volume of the aneurysm without reinforcing the neck.

In at least some cases, the biopolymer has a non-zero degree of chemical crosslinking within the first precursor material203before mixing with the chemical crosslinking agent. This can be useful, for example, to customize the curing window for the embolic element230so that it corresponds well with an expected amount of time needed to deliver the material to the aneurysm. The degree of chemical crosslinking of the biopolymer within the first precursor material203before mixing with the chemical crosslinking agent, the ratio of the biopolymer to the chemical crosslinking agent, and/or one or more other variables can be selected to cause the embolic element230to have a viscosity suitable for delivery to the aneurysm via the lumen of the conduit116for a suitable period of time (e.g., a period within a range from 10 minutes to 40 minutes) after mixing of the first and second precursor materials203,205. In at least some cases, the first and second precursor materials203,205are mixed in proportions that cause a weight ratio of the biopolymer to the chemical crosslinking agent in the resulting embolic element230to be within a range from 10:1 to 100:1, such as from 10:1 to 30:1, or from 15:1 to 50:1, or from 15:1 to 25:1. In a particular example, the first and second precursor materials203,205are mixed in proportions that cause a weight ratio of the biopolymer to the chemical crosslinking agent in the resulting embolic element230to be 30:1.

Use of a biopolymer instead of an artificial polymer in the first precursor material203may be advantageous because biopolymers tend to be more readily bioabsorbed than artificial polymers and/or for other reasons. Furthermore, use of a chemical crosslinking agent instead of a physical crosslinking agent (i.e., a crosslinking agent that forms noncovalent crosslinks between chains of the biopolymer) in the second precursor material205may be advantageous because chemically crosslinked polymers tend to be more cohesive than physically crosslinked polymers and/or for other reasons. In the context of forming a tissue scaffold within an aneurysm, high cohesiveness of the embolic element230may be more important than it is in other contexts to secure the cured embolic element230within the aneurysm302. For example, high cohesiveness of the embolic element230may reduce or eliminate the possibility of a piece of the embolic element230breaking free and entering a patient's intracerebral blood stream during delivery.

The first and second precursor materials203,205may include other components and/or the kit200may include other precursor materials intended for mixing with the first and second precursor materials203,205. For example, the first, second, and/or another precursor material may include a physical crosslinking agent. The presence of a physical crosslinking agent may be useful to form physical crosslinks that complement chemical crosslinks from the chemical crosslinking agent. The combination of chemical and physical crosslinks may enhance the cohesiveness of the embolic element230. Suitable physical crosslinking agents for use with chitosan-based biopolymers include β glycerophosphate, mannitol, glucose, and derivatives and analogs thereof. In these and other cases, the embolic element230may include multiple chemical crosslinking agents and/or multiple physical crosslinking agents.

A contrast agent is another component that may be added to the precursor materials. The presence of a contrast agent within the embolic element230can be useful to visualize delivery of the embolic element230using fluoroscopy. One problem with using conventional platinum coils in intracranial aneurysms is that the persistent radiopacity of the coils tends to interfere with visualizing other aspects of the treatment in follow-up imaging. For example, the presence of platinum coils within an aneurysm may make it difficult or impossible to detect by fluoroscopy the presence of blood-carried contrast agent that would otherwise indicate recanalization. In at least some embodiments of the present technology, a contrast agent within the embolic element230is selected to provide radiopacity that diminishes over time. For example, the contrast agent may initially be radiopaque to facilitate delivery of the embolic element230and then become less radiopaque to facilitate follow-up imaging. In a particular example, the first, second, and/or another precursor material includes iohexol or a derivative or analog thereof as a suitable contrast agent.

In animal studies, the liquid embolics of the present technology were shown to provide (a) complete or nearly complete volumetric filling of the aneurysm internal volume, and (b) complete or nearly complete coverage of the aneurysm neck with new endothelial tissue. These features, among others, are expected to result in a lower recanalization rate than that of platinum coil treatments and faster aneurysm occlusion than that of flow diverters. Furthermore, the injectable scaffold material is expected to be bioabsorbed and thereby reduced in volume over time. Thus, unlike platinum coils, the injectable scaffold is expected to have little or no long-term mass effect. Furthermore, the injectable scaffold material can be configured to have diminishing radiopacity; therefore, when so configured it will not interfere future CT and MRI imaging and procedures. Embodiments of the present technology can have these and/or other features and advantages relative to conventional counterparts whether or not such features and advantages are described herein.

In some embodiments, the embolic kit200and/or embolic element230may be any embolic or occlusive device, such as one or more embolic coils, polymer hydrogel(s), polymer fibers, mesh devices, or combinations thereof. The embolic kit200may include one or more precursors that, once mixed together, form the embolic element230that remains within the aneurysm. In some embodiments, the embolic kit200may include the embolic element pre-mixed.

In some embodiments, the embolic kit200and/or embolic element230may be any embolic or occlusive device, such as one or more embolic coils, polymer hydrogel(s), polymer fibers, mesh devices, or combinations thereof. The embolic kit200may include one or more precursors that, once mixed together, form the embolic element230that remains within the aneurysm. In some embodiments, the embolic kit200may include the embolic element pre-mixed.

Additional details regarding suitable embolic element may be found in U.S. patent application Ser. No. 15/299,929, filed Oct. 21, 2016, the disclosure of which is incorporated herein by reference in its entirety.

II. Selected Methods for Treating Aneurysms

FIGS.3A-3Gdepict an example method for treating an aneurysm A with the systems10of the present technology. To begin, a physician may intravascularly advance the second elongated shaft108towards an intracranial aneurysm (or other treatment location such as any of those described herein) with the occlusive member102in a low-profile state. A distal portion of the second elongated shaft108may be advanced through a neck N of the aneurysm A to locate a distal opening of the second elongated shaft108within an interior cavity of the aneurysm A. The elongated member106may be advanced distally relative to the second elongated shaft108to push the occlusive member102through the opening at the distal end of the second elongated shaft108, thereby releasing the occlusive member102from the shaft108and allowing the occlusive member102to self-expand into a first expanded state. Releasing the occlusive member102from the shaft108and allowing the occlusive member102to self-expand into a first expanded state may alternatively, or additionally, include withdrawing shaft108relative to the elongated member106.

FIG.3Ashows the occlusive member102in a first expanded state, positioned in an aneurysm cavity and still coupled to the elongated member106. As shown inFIG.3A, in the first expanded state, the occlusive member102may assume a predetermined shape that encloses an internal volume130(seeFIG.1C). In this first expanded state, the occlusive member102may generally conform to the shape of the aneurysm A. As illustrated inFIG.3Bwith the occlusive member102and delivery system shown in cross-section, the conduit116may be advanced through the internal volume130of the occlusive member102such that a distal opening of the conduit116is at or distal to the aperture126at the distal portion of the occlusive member102. The embolic element230may be delivered through the conduit116to a space between the occlusive member102and an inner surface of the aneurysm wall W. Although the illustrated example shows a separate conduit116extending through a lumen of the elongated member106, in other embodiments the elongated member106may itself form the conduit116, e.g., by extending through a proximal hub of the occlusive member102and through the internal volume130.

In some embodiments, the method includes mixing the first and second precursor materials203,205(FIG.2) to form the embolic element230. Mixing of the first and second precursor materials203,205may occur prior to introducing the embolic element230to the treatment system100and/or during delivery of the embolic element through the conduit116to the aneurysm. In a particular example, the first precursor material203is loaded into one of the barrels214, the second precursor materials205is loaded into the other barrel214, and the mixing syringes208are coupled via the coupler210. To mix the first and second precursor materials203,205, the plungers212are alternately depressed, thereby causing the first and second precursor materials203,205to move repeatedly from one barrel214to the other barrel214. After suitably mixing the precursor materials, the resulting embolic element230can be loaded into the barrel220of the injection syringe216. The injection syringe216may then be coupled to a proximal end of the conduit116to deliver the embolic element230through the conduit116and into the aneurysm A. As the embolic element230passes through the lumen of the conduit116, chemical crosslinking of the biopolymer can continue to occur.

Still with reference toFIG.3B, as the embolic element230is delivered between the dome of the aneurysm A and the distal portion132of the wall of the occlusive member102, pressure builds between the aneurysm wall W and the occlusive member102. As shown in the progression ofFIGS.3B-3D, when the forces on the occlusive member102reach a threshold level, the embolic element230pushes the distal wall132downwardly towards the neck N of the aneurysm A. The embolic element230exerts a substantially uniform pressure across the distal surface of the occlusive member102that collapses the occlusive member102inwardly on itself such that the rounded distal wall132transitions from concave towards the neck N of the aneurysm A to convex towards the neck N. The pressure and inversion of the distal portion of the wall132creates an annular fold136that defines the distal-most edge of the occlusive member102. As the occlusive member102continues to invert, the position of the fold136moves towards the neck N, which continues until a distal-most half of the occlusive member102has inverted. In some embodiments, the occlusive member102may include one or more portions configured to preferentially flex or bend such that the occlusive member102folds at a desired longitude. Moreover, as the occlusive member102collapses, a distance between the wall at the distal portion132and the wall at the proximal portion decreases, and thus the internal volume130of the occlusive member102also decreases. As the occlusive member102collapses, the conduit116may be held stationary, advanced distally, and/or retracted proximally.

During and after delivery of the embolic element230, none or substantially none of the embolic element230migrates through the pores of the occlusive member102and into the internal volume130. Said another way, all or substantially all of the embolic element230remains at the exterior surface or outside of the occlusive member102. Compression of the occlusive member with the embolic element230provides a real-time “leveling” or “aneurysm-filling indicator” to the physician under single plane imaging methods (such as fluoroscopy) so that the physician can confirm at what point the volume of the aneurysm is completely filled. It is beneficial to fill as much space in the aneurysm as possible, as leaving voids within the aneurysm sac may cause delayed healing and increased risk of aneurysm recanalization and/or rupture. While the scaffolding provided by the occlusive member102across the neck helps thrombosis of blood in any gaps and healing at the neck, the substantial filling of the cavity prevents rupture acutely and does not rely on the neck scaffold (i.e., the occlusive member102). Confirmation of complete or substantially complete aneurysm filling under single plane imaging cannot be provided by conventional devices.

Once delivery of the embolic element230is complete, the conduit116may be withdrawn. In some embodiments, the embolic element230may fill greater than 40% of the aneurysm sac volume. In some embodiments, the embolic element230may fill greater than 50% of the aneurysm sac volume. In some embodiments, the embolic element230may fill greater than 60% of the aneurysm sac volume. In some embodiments, the embolic element may fill greater than 65%, 70%, 75%, 80%, 85%, or 90% of the aneurysm sac volume.

FIG.3Eshows a second expanded state of the occlusive member102, shown in cross-section, with the embolic element230occupying the remaining volume of the aneurysm A.FIG.3Fshows the occlusive member102in full with the embolic element230removed so the second shape of the occlusive member102is visible. As shown, the embolic element230may be delivered until the occlusive member102is fully-collapsed such that the occlusive member102has substantially no internal volume.

In the second expanded state, the occlusive member102may form a bowl shape that extends across the neck of the aneurysm A. The wall of the occlusive member102at the distal portion may now be positioned in contact with or immediately adjacent the wall of the occlusive member102at the proximal portion. The distal wall132may be in contact with the proximal wall134along all or substantially all of its length. In some embodiments, the distal wall132may be in contact with the proximal wall134along only a portion of its length, while the remainder of the length of the distal wall132is in close proximity—but not in contact with—the proximal wall134.

Collapse of the occlusive member102onto itself, towards the neck N of the aneurysm, may be especially beneficial as it doubles the number of layers across the neck and thus increases occlusion at the neck N. For example, the distal wall132collapsing or inverting onto the proximal wall134may decrease the porosity of the occlusive member102at the neck N. In those embodiments where the occlusive member102is a mesh or braided device such that the distal wall132has a first porosity and the proximal wall134has a second porosity, deformation of the distal wall132onto or into close proximity within the proximal wall134decreases the effective porosity of the occlusive member102over the neck N. The resulting multi-layer structure thus has a lower porosity than the individual first and second porosities. Moreover, the embolic element230along the distal wall132provides additional occlusion. In some embodiments, the embolic element230completely or substantially completely occludes the pores of the adjacent layer or wall of the occlusion member102such that blood cannot flow past the embolic element230into the aneurysm cavity. It is desirable to occlude as much of the aneurysm as possible, as leaving voids of gaps can allow blood to flow in and/or pool, which may continue to stretch out the walls of aneurysm A. Dilation of the aneurysm A can lead to recanalization and/or herniation of the occlusive member102and/or embolic element230into the parent vessel and/or may cause the aneurysm A to rupture. Both conditions can be fatal to the patient.

In those embodiments where the wall of the occlusive member102comprises an inner and outer layer, the deformed or second shape of the occlusive member102forms four layers over the neck N of the aneurysm A In those embodiments where the wall of the occlusive member102comprises a single layer, the deformed or second shape of the occlusive member102forms two layers over the neck N of the aneurysm A As previously mentioned, the neck coverage provided by the doubled layers provides additional surface area for endothelial cell growth, decreases the porosity of the occlusive member102at the neck N (as compared to two layers or one layer), and prevents herniation of the embolic element230into the parent vessel. During and after delivery, the embolic element230exerts a substantially uniform pressure on the occlusive member102towards the neck N of the aneurysm A, thereby pressing the portions of the occlusive member102positioned adjacent the neck against the inner surface of the aneurysm wall such that the occlusive member102forms a complete and stable seal at the neck N.

As shown inFIG.3G, the first coupler112may be detached from the second coupler114and the elongated member106and second elongated shaft108may be withdrawn, thereby leaving the occlusive member102and embolic element230implanted within the aneurysm A. For example, the occlusive member102may be detached from the elongated member106using any of the electrolytic detachment mechanisms described in more detail below. In some examples, at least a distal portion of the conduit116may remain in place following detachment (e.g., electrolytic severance) of the elongated member106and/or conduit116.

Over time natural vascular remodeling mechanisms and/or bioabsorption of the embolic element230may lead to formation of a thrombus and/or conversion of entrapped thrombus to fibrous tissue within the internal volume of the aneurysm A. These mechanisms also may lead to cell death at a wall of the aneurysm and growth of new endothelial cells between and over the filaments or struts of the occlusive member102. Eventually, the thrombus and the cells at the wall of the aneurysm may fully degrade, leaving behind a successfully remodeled region of the blood vessel.

In some embodiments, contrast agent can be delivered during advancement of the occlusive member102and/or embolic element230in the vasculature, deployment of the occlusive member102and/or embolic element230at the aneurysm A, and/or after deployment of the occlusive member102and/or embolic element230prior to initiation of withdrawal of the delivery system. The contrast agent can be delivered through the second elongated shaft108, the conduit116, or through another catheter or device commonly used to delivery contrast agent. The aneurysm (and devices therein) may be imaged before, during, and/or after injection of the contrast agent, and the images may be compared to confirm a degree of occlusion of the aneurysm.

According to some aspects of the technology, the system10may comprise separate first and second elongated shafts (e.g., microcatheters) (not shown), the first dedicated to delivery of the embolic element, and the second dedicated to the delivery of the occlusive member. In example methods of treating an aneurysm, the first elongated shaft may be intravascularly advanced to the aneurysm and through the neck such that that a distal tip of the first elongated shaft is positioned within the aneurysm cavity. In some embodiments, the first elongated shaft may be positioned within the aneurysm cavity such that the distal tip of the shaft is near the dome of the aneurysm.

The second elongated shaft containing the occlusive member (such as occlusive member102) may be intravascularly advanced to the aneurysm and positioned within the aneurysm cavity adjacent the first elongated shaft. The occlusive member may then be deployed within the aneurysm sac. As the occlusive member is deployed, it pushes the first elongated shaft outwardly towards the side of the aneurysm, and when fully deployed the occlusive member holds or “jails” the first elongated shaft between an outer surface of the occlusive member and the inner surface of the aneurysm wall.

The embolic element (such as embolic element230) may then be delivered through the first elongated shaft to a position between the inner surface of the aneurysm wall and the outer surface of the occlusive member. For this reason, it may be beneficial to initially position the distal tip of the first elongated shaft near the dome (or more distal surface) of the aneurysm wall. This way, the “jailed” first elongated shaft will be secured by the occlusive member such that the embolic element gradually fills the open space in the aneurysm sac between the dome and the occlusive member. As described elsewhere herein, the filling of the embolic element pushes and compresses the occlusive member against the tissue surrounding the aneurysm neck as the space in the sac above the occlusive member is being filled from the dome to the neck. Also as described elsewhere herein, the compression of the occlusive member with the embolic element provides a “leveling or aneurysm filling indicator” which is not provided by conventional single plane imaging methods. The filling of the embolic element may complete, for example, when it occupies about 50-80% of the volume of the aneurysm.

III. Example Systems with Electrolytic Detachment Mechanisms

FIG.4Ashows a schematic side view of a treatment system400, andFIG.4Bshows a side cross-sectional view of a distal portion of the treatment system400shown inFIG.4A. As described in more detail below, the treatment system400can include a conduit assembly402that is releasably coupled to the occlusive member102. In operation, the treatment system400facilitates placement of the occlusive member102at the treatment site and utilizes electrolytic detachment to release the occlusive member102from the conduit assembly402. As described in more detail below, a distal portion of the conduit assembly402may remain in place alongside the occlusive member102following electrolytic detachment. Furthermore, the conduit assembly402can facilitate introduction of an embolic element230(FIGS.2-3G) therethrough for placement at the treatment site (e.g., within an aneurysm sac accompanying the occlusive member102).

Although several examples refer to the use of electrolytic detachment, in various embodiments other techniques can be used to sever a conduit and release the occlusive member102. For example, instead of or in addition to electrolytic detachment, embodiments of the present technology may utilize thermal detachment, mechanical detachment, chemical detachment, or any other suitable detachment techniques.

Referring toFIGS.4A and4Btogether, the conduit assembly402can take the form of an elongated tubular member defining a lumen404therein. The conduit assembly402can be coupled to a proximal hub406of the occlusive member102, such that the lumen404extends distally beyond the proximal hub406. As shown inFIG.4B, an inner band408of the hub406circumferentially surrounds a portion of the conduit assembly402. An outer band410surrounds the inner band408, such that proximal portions of the layers of the occlusive member102are grasped between the inner and outer bands408,410of the hub406. Such bands can be made of any suitable material, for example being polymeric or metallic, and optionally may be radiopaque to facilitate visualization of the system400as it advanced through the vasculature. The bands can be crimped, with or without an adhesive or weld, to secure them in place. In operation, an embolic element can be introduced via the lumen404into the treatment site (e.g., within an aneurysm sac) and adjacent the occlusive member102. In some examples, the inner band408can have an inner diameter of about 0.020 inches, and the outer band410can have an outer diameter of about 0.023 inches.

In various embodiments, the conduit assembly402can include a single tubular member or a plurality of tubular members arranged coaxially. Moreover, any one of the tubular members can be monolithic or can be formed of multiple separate components joined together. Additionally or alternatively, some or all of the tubular member(s) can include one or more coatings along some or all of their respective lengths. In some embodiments, one or more of the tubular members can be slidably moveable with respect to other tubular members. Alternatively or additionally, one or more of the tubular members can be fixed (e.g., non-slidably coupled) with respect to the other tubular members.

In the embodiment illustrated inFIGS.4A-4B, the conduit assembly402includes a conduit420which takes the form of an elongated tubular member. An outer sheath430extends along a radially outer surface of the conduit420, and an inner liner440extends along a radially inner surface of the conduit420. As described in more detail below, the conduit420can include a detachment zone426configured to be electrolytically corroded when current is supplied to the conduit420. The outer sheath430and/or the inner liner440can be electrically insulative such that current carried by the conduit420is confined to the conduit420and focused at the detachment zone426. When in the presence of an electrolytic medium, such as blood, current passes from the conduit420to the surrounding media through the detachment zone426.

In various embodiments, the conduit assembly402can have a length sufficient to permit the occlusive member102to be positioned at an intravascular treatment site (e.g., within an aneurysm sac) while a proximal end of the conduit assembly402extends outside the patient's body. For example, the conduit assembly402can have a length of greater than about 50 inches, 60 inches, 70 inches, or 80 inches. The conduit assembly402can have an outer diameter suitable to permit the assembly402to be slidably advanced through a delivery catheter. For example, the conduit assembly402can have an outer diameter of less than about 0.027 inches, less than about 0.021 inches, or less than about 0.017 inches.

In the example shown inFIGS.4A-4B, the conduit assembly402extends through the hub406of the occlusive member102, with a stepped down diameter at the hub406resulting in a narrower lumen404in a distal portion of the conduit assembly402that extends through the hub406and distal to the hub406. In some embodiments, this stepped-down diameter can result from crimping the hub406over the conduit assembly402. In other embodiments, however, the conduit assembly402need not have such a stepped-down inner and/or outer diameter. For example, the conduit assembly402can have an outer diameter and/or an inner diameter that is substantially constant along its length, or that tapers gradually along some or all of its length.

As noted above, the conduit assembly402includes a conduit420, which can be radially disposed between an outer sheath430and an inner liner440. The conduit420includes a proximal portion422, a distal portion424, and a detachment zone426disposed axially between the proximal portion422and the distal portion424. In some embodiments, the conduit420can be an electrically conductive tubular member, for example a hypotube, catheter, or other suitable tubular member. In some embodiments, a portion of the conduit420, including the detachment zone426, can be coated with a conductive material, such as carbon, gold, platinum, tantalum, combinations thereof, and the like. One or more metallic coatings can be applied using known plating techniques. In various embodiments, the conduit420can have cuts (e.g., a spiral cut, a groove, etc.) along at least a portion of its length to achieve the desired mechanical properties (e.g., column strength, flexibility, kink-resistance, etc.).

The conduit420can be dimensioned to facilitate intravascular advancement to the treatment site and to accommodate a lumen404sufficient to permit advancement of embolic element(s) therethrough. In some embodiments, the conduit420can have a wall thickness of between about 0.0005 inches and about 0.0015 inches, or about 0.001 inches in some examples. The conduit420can have an outer diameter in the proximal portion of less than about 0.027 inches, less than about 0.021 inches, or less than about 0.017 inches. Additionally or alternatively, the conduit420can have an inner diameter of less than about 0.015 inches, less than about 0.012 inches, less than about 0.010 inches, or less than about 0.008 inches. As shown inFIG.4B, the conduit420can have a stepped-down diameter where the conduit420passes through the hub406. For example, the conduit420can have an outer diameter of about 0.016 inches proximal to the hub406, and an outer diameter of about 0.014 inches within the hub406. This reduced diameter can be achieved by crimping the bands of the hub406over the conduit420, or by forming the conduit420with a stepped-down profile prior to coupling the conduit420to the hub406.

The conduit420, including the detachment zone426, can include one or more of the following materials: ceramic materials, plastics, base metals or alloys thereof, for example stainless steel or nitinol. Some of the most suitable material combinations for forming the electrolytically corrodible points can include one or more of the following: stainless steels, preferably of the type AISI 301, 304, 316, or subgroups thereof; Ti or TiNi alloys; Co-based alloys; noble metals; or noble metal alloys, such as Pt, Pt metals, Pt alloys, Au alloys, or Sn alloys. Further, ceramic materials and plastics employed for forming the medical device can be electrically conductive.

In some embodiments, the detachment zone426can include features to facilitate electrolytic severability, such as features configured to reduce a time that current must be supplied to the conduit420before the conduit is severed at the detachment zone426. In some embodiments, the detachment zone426can include a sidewall having one or more openings428formed therein, which can take the form of one or more windows, slits, apertures, holes, or other such features. The openings428can both increase the surface-area-to-volume ratio at the detachment zone426, and can also reduce the overall amount of material forming the sidewall of the conduit420at the detachment zone426. As a result, the sidewall material of the conduit420at the detachment zone426may be more readily electrolytically corroded when current is supplied to the conduit420and the detachment zone426is exposed to an electrolytic medium such as blood. Additionally or alternatively to the openings428, the detachment zone426can include a reduced sidewall thickness of the conduit420, and/or otherwise provide a lower material density than the proximal and distal portions422,424of the conduit420. In some embodiments, the detachment zone426can be surface treated (e.g., using laser or chemical treatment) to create a microstructure at the detachment zone426that differs from that of the proximal and distal portions422,424of the conduit420to facilitate electrolytic detachment. For example, the detachment zone426can have a microstructure having a lower crystallinity than each of the conduit proximal portion422and conduit distal portion424. As another example, the detachment zone426can have a microstructure that is more amorphous than each of the conduit proximal portion422and conduit distal portion424.

According to some embodiments, portions of the conduit420can be covered with an electrically insulative material. For example, a sheath430that is made of or includes an electrically insulative material can extend over a radially outer surface of the conduit420along at least a portion of the length of the conduit420. For example, the sheath430can include a proximal portion432that circumferentially surrounds an outer surface of the conduit proximal portion422. The sheath430can also include a distal portion434that circumferentially surrounds an outer surface of the conduit distal portion424. A void or gap436can separate the sheath proximal and distal portions432,434. In some embodiments, the sheath proximal and distal portions432,434can be discrete members that are not connected to one another, while in other embodiments the proximal and distal portions432,434may be connected across the gap436, for example via connecting strands of material.

The sheath430can be fully or partially made of an electrically nonconductive or insulative polymer, such as polyimide, polypropylene, polyolefins, combinations thereof, and the like. In some embodiments, the sheath430takes the form of an extruded polymeric tube (e.g., PTFE), and the sheath430extends distally beyond the hub406and distally beyond a distal end of the conduit420. Accordingly, in some embodiments, the sheath430can define the distal opening of the conduit assembly402. In some embodiments, the distal end of the sheath430is disposed adjacent or distal to a distal end of the occlusive member102when the occlusive member102is in its expanded state. According to some embodiments, the distal end of the sheath430is disposed adjacent or distal to a distal end of the occlusive member102when the occlusive member102is in its low-profile state.

The sheath430can be dimensioned to facilitate intravascular advancement to the treatment site and to accommodate a lumen404sufficient to permit advancement of embolic element(s) therethrough. In some embodiments, the sheath430can have a wall thickness of between about 0.0005 inches and about 0.002 inches, or about 0.0015 inches in some examples. The sheath430can have an outer diameter in the proximal portion of less than about 0.027 inches, less than about 0.021 inches, less than about 0.017 inches, or less than about 0.015 inches. Additionally or alternatively, the sheath430can have an inner diameter of less than about 0.015 inches, less than about 0.012 inches, less than about 0.010 inches, or less than about 0.008 inches. As shown inFIG.4B, the sheath430can have a stepped-down diameter, similar to that described above with respect to the conduit420.

According to some embodiments, a gap436between the sheath proximal and distal portions432,434leaves exposed the detachment zone426of the underlying conduit420. When in contact with a body fluid, such as blood, the fluid serves as an electrolyte allowing current to be focused on the non-covered detachment zone426. The sheath proximal and distal portions422,424prevent exposure of the conduit proximal portion422and the conduit distal portion424to the fluid. Accordingly, electrical energy conducted along the conduit420is concentrated at the detachment zone426, thereby reducing the time required to erode away the detachment zone426. The sheath proximal and distal portions432,434can be slidably disposed over, over-molded, co-extruded, sprayed on, or dip-coated with respect to the conduit420.

The gap436between the sheath proximal portion432and the sheath distal portion434can be dimensioned so as to achieve the desired exposure of the underlying detachment zone426. According to some embodiments, the gap436can be as small as 0.0005 inches and as large as 0.1 inches or longer. According to some embodiments, lengths of detachment zone426can be greater than 0.005 inches and/or less than 0.010 inches to provide sufficient exposure to achieve detachment times of less than 30 seconds.

According to some embodiments, the sheath distal portion434is disposed radially between the distal portion424of the conduit420and the hub406of the occlusive member102. As shown inFIG.4B, the inner band408of the hub406circumferentially surrounds and contacts the distal portion434of the sheath430. The insulative sheath distal portion434can electrically isolate the occlusive member102from an electrical charge conducted along a length of the conduit420. A proximal end of the sheath distal portion434may be positioned proximal to the hub406, and a distal end of the sheath distal portion434may be positioned distal to the hub406. Alternatively, the proximal end of the sheath distal portion434may be coterminous with a proximal end of the hub406, and/or a distal end of the sheath distal portion434may be coterminous with a distal end of the hub406.

As noted above, an inner liner440can be disposed radially inwardly of the conduit420. The liner440can be an elongate tubular member and can be made of an electrically insulative material. In some embodiments, the liner440can have an inner surface defining the lumen404along at least a portion of the length of the conduit assembly402. Accordingly, the inner surface of the liner440can be continuous and uninterrupted along its length, such that liquid embolic material passing therethrough is contained within the lumen404until it reaches a distal end of the liner440. In particular, the liner440can provide a continuous and uninterrupted surface along the detachment zone426of the conduit420, such that any embolic element(s) cannot pass from within the lumen404through the openings428in the conduit420at the detachment zone426.

In various embodiments, the liner440can extend distally to be coterminous with the conduit420(e.g., at or adjacent a distal end of the hub406), or alternatively the liner440can extend distally beyond the hub406and/or distally beyond a distal end of the conduit420. The liner440can be made of or coated with a lubricious material to facilitate advancement of embolic element(s) therethrough. In some embodiments, the liner440takes the form of an extruded polymeric tube (e.g., PTFE) or other suitable electrically insulative material. Additionally or alternatively, the inner liner440can be co-extruded, sprayed on, or dip-coated with respect to the conduit420.

The liner440can be dimensioned to facilitate intravascular advancement to the treatment site and to accommodate a lumen404sufficient to permit advancement of embolic element(s) therethrough. In some embodiments, the liner440can have a wall thickness of between about 0.0005 inches and about 0.0015 inches, or about 0.001 inches in some examples. The liner440can have an outer diameter in the proximal portion of less than about 0.027 inches, less than about 0.021 inches, or less than about 0.017 inches. Additionally or alternatively, the liner440can have an inner diameter of less than about 0.015 inches, less than about 0.012 inches, less than about 0.010 inches, or less than about 0.008 inches. As shown inFIG.4B, the liner440can have a stepped-down diameter where the liner440passes through the hub406, similar to that of the conduit420and sheath430described above.

In some embodiments, an embolic element can be delivered through the lumen404of the conduit assembly402. The lumen404can terminate in a distal opening (not shown). As noted above, in some embodiments, the conduit assembly402can include an elongate flexible tubular member, for example a catheter, hypotube, polymer tube, etc. The lumen404can be coated with a lubricious material or lining to facilitate advancement of embolic element(s) therethrough. In some embodiments, the conduit assembly402is dimensioned such that the distal opening is disposed adjacent to, completely distal of, or at least partially distal of the occlusive member102while the occlusive member102is in the unexpanded state. The conduit assembly402can be dimensioned and configured such that the distal opening is disposed at distal to the hub406of the occlusive member102, such that embolic element(s) delivered therethrough can be delivered to a region adjacent or distal of the occlusive member102.

FIG.4Cillustrates the treatment system400with the conduit assembly402partially retracted following electrolytic severance of the conduit420at the detachment zone426. As illustrated, the sheath distal portion422and the conduit distal portion424can remain coupled to the hub406of the occlusive member102, while the sheath proximal portion422, conduit distal portion422, and the liner440are retracted proximally. According to some embodiments, the conduit assembly420can be retracted through a surrounding catheter and removed from the body completely.

FIG.5shows a schematic side view of another embodiment of a treatment system500in accordance with aspects of the present technology. The treatment system500can include several features that are generally similar to those ofFIGS.4A-4Cdescribed above. However, in the treatment system500shown inFIG.5, the liner440includes a proximal portion442and a distal portion424that are spaced apart from one another by a gap446that is axially aligned with the detachment zone426. In this configuration, following electrolytic severance of the conduit420at the detachment zone426, the liner distal portion444may remain in place along with the occlusive member102, the conduit distal portion424, and the sheath distal portion434. As such, the liner proximal portion442can be retracted along with the conduit proximal portion422and sheath proximal portion432.

FIG.6shows a schematic side view of another embodiment of a treatment system600in accordance with aspects of the present technology. The treatment system600can include several features that are generally similar to those ofFIGS.4A-5described above. However, in the treatment system600shown inFIG.6, the liner440terminates at or proximal to the detachment zone426. In this configuration, the lumen404is defined by the liner440along a portion of the length of the treatment system600, and is defined by the inner surface of the conduit420along a distal portion of the conduit assembly402.

FIG.7shows a schematic side view of another embodiment of a treatment system700in accordance with aspects of the present technology. The treatment system700can include several features that are generally similar to those ofFIGS.4A-6described above. However, in the treatment system700shown inFIG.7, the sheath430terminates distally at or adjacent a distal end of the hub406. Accordingly, the sheath430and the conduit420can be substantially co-terminal. Meanwhile, the inner liner440can extend distally beyond the hub406and beyond the distal ends of the conduit420and sheath430. Accordingly, in this configuration, the lumen404is defined along its entire length by the inner surface of the liner440. Following severance of the conduit420at the detachment zone426, the liner440can be proximally retracted along with the conduit proximal portion422and the sheath proximal portion432. As such, following this proximal retraction, there remains no tubular member extending into an interior of the occlusive member102, in contrast to the embodiments described above with respect toFIGS.4A-4C. This arrangement may be beneficial if it is desirable to remove any tubular element from within the sac of the aneurysm following deployment of the occlusive member102and any embolic element(s).

FIGS.8A-8Cillustrate delivery of an occlusive member102and embolic element230to a treatment site within an aneurysm sac. As shown inFIG.8A, the treatment system400can be positioned within a second elongate shaft108(e.g., a microcatheter) for intravascular advancement until the microcatheter is at or adjacent to the aneurysm sac. In the illustrated embodiment, the distal end of the second elongate shaft108extends within the aneurysm sac, however in other embodiments the distal end of the second elongate shaft108can be positioned at the neck of the aneurysm or proximal to the neck of the aneurysm.

In the position shown inFIG.8A, the system400has been advanced within the elongate shaft108such that the occlusive member102remains in a constrained, low-profile configuration within the shaft108while at least a portion of the conduit assembly402extends adjacent to the occlusive member102and within the shaft108. In various embodiments, the shaft108can have an inner diameter of about 0.017 inches or less, about 0.021 inches or less, or about 0.027 inches or less.

As shown inFIG.8B, once the distal opening450of the conduit assembly402is positioned at or near the treatment site (e.g., within the aneurysm sac), the elongate shaft108can be retracted, thereby deploying the occlusive member102within the aneurysm sac (e.g., allowing the occlusive member102to self-expand). In this position, the embolic element230can be advanced through the conduit assembly402and into the aneurysm to a region distal to the occlusive member102. In the case of a fluid or gel, a syringe or other injector may be used to urge the embolic element230through the lumen404. In the case of microcoils or other structural embolic element(s), a delivery wire or other suitable mechanism may be slidably advanced through the lumen404of the conduit assembly402to position the embolic element230into the aneurysm sac.

As described previously with respect toFIGS.3A-3G, introduction of the embolic element230can cause the occlusive member102to deform, for example to at least partially fold in on itself to provide for increased protection in a neck region of the aneurysm. Once the embolic element230been delivered and the occlusive member102has deformed, the occlusive member102can be severed from the conduit assembly402as described above. For example, a power supply or other current source can be used to generate current through the conduit420, resulting in electrolytic corrosion of the conduit420at the detachment zone426.

As shown inFIG.8C, after the occlusive member102is released via electrolytic corrosion of the detachment zone426, the conduit assembly402can be proximally retracted while the occlusive member102and the embolic element230remain positioned within the aneurysm. As the conduit assembly402is retracted, the distal portion of the conduit assembly (e.g., the distal portion434of the sheath430and/or the distal portion424of the conduit420) can remain within the aneurysm and coupled to the occlusive member102.

IV. CONCLUSION

Although many of the embodiments are described above with respect to systems and methods related to treatment of hemorrhagic stroke, the technology is applicable to other applications and/or other approaches. Moreover, other embodiments in addition to those described herein are within the scope of the technology. Additionally, several other embodiments of the technology can have different configurations, components, or procedures than those described herein. A person of ordinary skill in the art, therefore, will accordingly understand that the technology can have other embodiments with additional elements, or the technology can have other embodiments without several of the features shown and described above with reference toFIGS.1A-8C.

The descriptions of embodiments of the technology are not intended to be exhaustive or to limit the technology to the precise form disclosed above. Where the context permits, singular or plural terms may also include the plural or singular term, respectively. Although specific embodiments of, and examples for, the technology are described above for illustrative purposes, various equivalent modifications are possible within the scope of the technology, as those skilled in the relevant art will recognize. For example, while steps are presented in a given order, alternative embodiments may perform steps in a different order. The various embodiments described herein may also be combined to provide further embodiments.

Unless otherwise indicated, all numbers expressing dimensions, percentages, or other numerical values used in the specification and claims, are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present technology. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Additionally, all ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein. For example, a range of “1 to 10” includes any and all subranges between (and including) the minimum value of 1 and the maximum value of 10, i.e., any and all subranges having a minimum value of equal to or greater than 1 and a maximum value of equal to or less than 10, e.g., 5.5 to 10.

Moreover, unless the word “or” is expressly limited to mean only a single item exclusive from the other items in reference to a list of two or more items, then the use of “or” in such a list is to be interpreted as including (a) any single item in the list, (b) all of the items in the list, or (c) any combination of the items in the list. Additionally, the term “comprising” is used throughout to mean including at least the recited feature(s) such that any greater number of the same feature and/or additional types of other features are not precluded. It will also be appreciated that specific embodiments have been described herein for purposes of illustration, but that various modifications may be made without deviating from the technology. Further, while advantages associated with certain embodiments of the technology have been described in the context of those embodiments, other embodiments may also exhibit such advantages, and not all embodiments need necessarily exhibit such advantages to fall within the scope of the technology. Accordingly, the disclosure and associated technology can encompass other embodiments not expressly shown or described herein.