US 20060155323 A1
Devices for occluding an aneurysm are provided. In particular, the device include an upper member that sits against the dome of the aneurysm, a lower member that sits in the neck of the aneurysm, and a means of adjusting the overall dimensions of the device. Also provided are methods of making and using these devices.
1. A vaso-occlusive device for placement within an aneurysm having a neck and a dome, the device comprising
a lower member having a linear configuration prior to deployment and a deployed open configuration, wherein the deployed configuration bridges the neck of the aneurysm;
an upper member having a undeployed, linear configuration prior and an open, deployed configuration, wherein the deployed configuration rests against at least a portion of the dome of the aneurysm, and
a means of adjusting the overall dimensions of the device.
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30. A method of occluding a body cavity comprising introducing a vaso-occlusive device according to
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Compositions and methods for repair and treatment of aneurysms are described. In particular, devices and systems for placement in an aneurysm are disclosed, as are methods of making and using these devices.
An aneurysm is a dilation of a blood vessel that poses a risk to health from the potential for rupture, clotting, or dissecting. Rupture of an aneurysm in the brain causes stroke, and rupture of an aneurysm in the abdomen causes shock. Cerebral aneurysms are usually detected in patients as the result of a seizure or hemorrhage and can result in significant morbidity or mortality.
There are a variety of materials and devices which have been used for treatment of aneurysms, including platinum and stainless steel microcoils, polyvinyl alcohol sponges (Ivalone), and other mechanical devices. For example, vaso-occlusion devices are surgical implements or implants that are placed within the vasculature of the human body, typically via a catheter, either to block the flow of blood through a vessel making up that portion of the vasculature through the formation of an embolus or to form such an embolus within an aneurysm stemming from the vessel. One widely used vaso-occlusive device is a helical wire coil having windings that may be dimensioned to engage the walls of the vessels. (See, e.g., U.S. Pat. No. 4,994,069 to Ritchart et al.). Other less stiff helically coiled devices have been described, as well as those involving woven braids. See, e.g., U.S. Pat. No. 6,299,627.
U.S. Pat. No. 5,354,295 and its parent, U.S. Pat. No. 5,122,136, both to Guglielmi et al., describe an electrolytically detachable embolic device. Vaso-occlusive coils having little or no inherent secondary shape have also been described. For instance, co-owned U.S. Pat. Nos. 5,690,666; 5,826,587; and 6,458,119 by Berenstein et al., describes coils having little or no shape after introduction into the vascular space. U.S. Pat. No. 5,382,259 describes non-expanding braids covering a primary coil structure.
However, there is a risk that known coil designs will migrate fully or partially out of the aneurysm entrance zone and into the feeding vessel. This risk is particularly high with wide neck aneurysms. Generally, wide neck aneurysms are those in which the neck (the entrance zone) has a diameter that either: (1) is at least 80% of the largest diameter of the aneurysm; or (2) is clinically observed to be too wide effectively to retain vaso-occlusive coils that are deployed using the techniques discussed above. Accordingly, devices for retaining coils within aneurysms have been described. See, e.g., U.S. Pat. No. 6,168,622 and U.S. Patent Application Publication No. 20030195553.
Thus, there remains a need for systems and methods for occluding an aneurysm neck would be desirable, including systems that do not rely on coils that may migrate out of aneurysms.
Thus, this invention includes novel occlusive devices as well as methods of using and making these devices.
In one aspect, the invention includes a vaso-occlusive device for placement within an aneurysm having a neck and a dome, the device comprising a lower member having a linear configuration prior to deployment and a deployed open configuration, wherein the deployed configuration bridges the neck of the aneurysm; an upper member having a undeployed, linear configuration prior and an open, deployed configuration, wherein the deployed configuration rests against at least a portion of the dome of the aneurysm, and a means of adjusting the overall dimensions of the device. In certain embodiments, the distance between the upper and lower members is adjustable. In other embodiments, the lower and/or upper member is compressible (e.g., deformable against the wall of the aneurysm).
In any of the devices described herein, the upper and lower members may be contiguous or alternatively, the upper and lower members may be separate, for example when the device further comprises an adjustable central member having a proximal end connected to the lower member and distal end connected to the upper member. One or more of the upper member lower member and optional central member may be compressible or may comprise a compressible element. Furthermore, the optional central member may further comprise an extendable member connected to the upper member; and/or an expandable element.
In any of the devices described herein, the upper member may comprise a plurality of axially moveable wires passing through the lumen of the central member, each wire comprising a distal end and a proximal end. In certain embodiments, the distal end of one or more of the wires is attached to the central member and/or to the lower member. The upper member may be compressible or deformable, for example against the dome of an aneurysm, thereby changing the overall dimensions of the device.
In another aspect, the invention includes any of the devices as described herein, which device further comprises one or more detachment junctions, each detachment junction comprising an electrolytically detachable end adapted to detach by imposition of a current thereon. One or more detachment junctions may be positioned between the upper member and a pusher wire and/or between the lower member and a pusher tube.
In another aspect, the invention includes any of the devices as described herein, which device further comprises one or more locking mechanisms. In certain embodiments, the locking mechanism comprises an expandable material, for example a self-expanding element.
In yet another aspect, the invention includes any of the devices as described herein, wherein the upper member comprises a metal, for example, a metal selected from the group consisting of nickel, titanium, platinum, gold, tungsten, iridium and alloys or combinations thereof. In certain embodiments, the upper member comprises the alloy nitinol.
In yet another aspect, the invention includes any of the devices as described herein, wherein the lower member comprises a metal, for example a metal selected from the group consisting of platinum, palladium, rhodium, gold, tungsten and alloys thereof. In certain embodiment, the lower member comprises nitinol.
In yet another aspect, the invention includes any of the devices as described herein, wherein the upper and/or lower member comprises a braid or mesh configuration. In certain embodiments, the lower member comprises a mesh or braid structure. In other embodiments, the lower member comprises a film (e.g., a porous film, a polymer film or a metallic film).
In a still further aspect, the invention includes any of the devices as described herein, which device further comprises an additional component, for example a bioactive component.
In yet another aspect, the invention includes a method of occluding a body cavity comprising introducing a vaso-occlusive device as described herein into the body cavity (e.g., an aneurysm). These and other embodiments of the subject invention will readily occur to those of skill in the art in light of the disclosure herein.
In order to better appreciate how the devices, methods and other advantages and objects of the present disclosure, a more particular description will be rendered by reference to specific embodiments thereof, which are illustrated in the accompanying drawings. It is to be understood that the drawings depict only exemplary embodiments and are not to be considered limiting in scope.
Occlusive (e.g., embolic) devices are described. The devices described herein find use in vascular and neurovascular indications and are particularly useful in treating aneurysms, for example wide-neck, small-diameter, curved or otherwise difficult to access vasculature, for example aneurysms, such as cerebral aneurysms. Methods of making and using these vaso-occlusive devices also form aspects of this invention.
All publications, patents and patent applications cited herein, whether above or below, are hereby incorporated by reference in their entirety.
It must be noted that, as used in this specification and the appended claims, the singular forms “a”, “an”, and “the” include plural references unless the content clearly dictates otherwise. Thus, for example, reference to a device comprising “an extendable member” includes devices comprising of two or more elements.
The device is a surgical implement and can be readily deployed, removed and/or repositioned in human vasculature. Typically, the devices include a lower member, an upper member and a means for adjusting the overall dimensions of the device, including, for example, a means of adjusting the distance between the lower and upper members. The upper and lower members may be separate or contiguous elements. In addition, one or both of the upper and lower members may be compressible. The lower member typically sits in the neck of the aneurysm while the upper member sits against the walls (e.g., dome) of the aneurysm.
Overall dimensions of the device are changed using any suitable adjustment means. For example, in certain embodiments, the upper and/or lower member may be moved in relation to each other (e.g., extended, expanded, compressed, etc.) in order to change the overall dimensions of the device. One or more adjustable elements (e.g., a central member) may be employed to facilitate the change the dimensions, for example an extendable central member connecting the lower and upper members may be included.
Depicted in the Figures are exemplary embodiments of the present invention. It will be appreciated that this is for purposes of illustration only and that the various elements depicted can be of other materials or shapes.
In embodiments in which the upper and lower members are contiguous, the contiguous structure may take any number of forms, including but not limited to, wires (FIG. SB), braided or woven configurations, solid configurations (
As shown in the Figures, the overall dimensions of the devices described herein are adjustable, thereby facilitating a transfer of force between the lower member (in the neck) to the upper member (the dome of the aneurysm). The dimensions can be adjusted (and force transferred) in a variety of ways, including but not limited to, the inclusion a moveable central member; a moveable upper member; springs; and/or expandable elements such as balloons. Whatever force transfers design or combinations of designs are employed, the adjustable nature of the dimension(s) of the devices described herein aid in ensuring that the lower member sits in the neck the aneurysm while the upper member presses safely against the dome of the aneurysm. Preferably, the area of contact between the upper and the aneurysm wall is maximized so as to distribute the force across the widest possible area and thus exert the least amount of pressure on the aneurysm wall. Furthermore, it is to be understood that one or more design features shown in the Figures and described herein can be combined into one device.
Although the devices described herein are capable of retaining finer vaso-occlusive devices (e.g., coils, liquid embolics, etc.) within the aneurysm, they are also capable of functioning as vaso-occlusive devices by themselves. As can be appreciated by one of ordinary skill in the art, the force-transfer effect achieved by including one or more adjustment means (e.g., moveable elements) serves to anchor the device in the aneurysm and reinforce the lower member so that it is able to remain stably situated across the aneurysm neck while diverting the flow of blood from within the aneurysm.
As will be apparent, the devices described herein may conform to a range of shapes and sizes of aneurysms since the dimensions are adjustable. Furthermore, following the teachings described herein, the devices can be sized to fit aneurysms ranging in size from millimeters in diameter to centimeters in diameter. In this way, the operator can select a device of a generally suitable size for the particular indication and adjust it to fit securely by conforming the upper member to the dome of the aneurysm.
As noted above, the lower member and upper members may assume a variety of structures, for example, umbrella, dome, balloon, teardrop or cone shape. The deployed configuration of the lower member is preferably such that it sits in and covers the neck of the aneurysm. Similarly, the deployed configuration of the upper member is such that it sits safely against the dome of the aneurysm (e.g., back inner wall). Generally, the overall structure of the upper member is typically more variable than that of the lower member and includes, but is not limited to, configuration such as umbrella shapes, strings or wires formed into loops, etc. One or both of the lower and upper members may also include thin-film, braided, mesh like or basket type structures. Furthermore, the upper and lower members may be a single element, for example expandable structures, for example as shown in
Upper and lower members can be constructed from a wide variety of materials, including, but not limited to, metals, metal alloys, polymers or combinations thereof. See, e.g., U.S. Pat. Nos. 6,585,754 and 6,280,457 for a description of various polymers. Non-limiting examples of suitable metals include, Platinum Group metals, especially platinum, rhodium, palladium, rhenium, as well as tungsten, gold, silver, tantalum, stainless steel and alloys of these metals. Preferably, the lower member comprises a material that maintains its shape despite being subjected to high stress, for example, “super-elastic alloys” such as nickel/titanium alloys (48-58 atomic % nickel and optionally containing modest amounts of iron); copper/zinc alloys (38-42 weight % zinc); copper/zinc alloys containing 1-10 weight % of beryllium, silicon, tin, aluminum, or gallium; or nickel/aluminum alloys (36-38 atomic % aluminum). Particularly preferred are the alloys described in U.S. Pat. Nos. 3,174,851; 3,351,463; and 3,753,700. Especially preferred is the titanium/nickel alloy known as “nitinol.”
Shape memory alloys comprise a unique class of metal alloys that, once trained, are configured to “remember” a pre-selected shape, i.e., deployed shape, and can return to the pre-selected shape even if subsequently reshaped. To be trained to “remember” a first pre-selected shape, the shape memory alloy is molded and heated at or above a training, or austenite, temperature to place the shape memory alloy in an austenite phase. In the austenite phase, the shape memory alloy is formed in the first pre-selected shape and then, once formed, is permitted to cool to a martensite finish temperature, whereupon the shape memory alloy enters a martensite phase. The martensite finish temperature can be any temperature that is less than the training temperature. Upon entering the martensite phase, the shape memory alloy has been trained to “remember” the first pre-selected shape. While in the martensite phase, the alloy is in a soft state and is formed into a second pre-selected shape, e.g., an undeployed shape. The shape memory alloy in the martensite phase is configured to maintain the second pre-selected shape and, if subsequently reheated to an activation temperature, automatically returns to the first pre-selected shape. The activation temperature can comprise any temperature that is greater than the martensite finish temperature and generally approximately equals the training temperature. Once the first pre-selected shape has been recovered, the shape memory alloy is configured to maintain the first pre-selected shape irrespective of temperature. Generally, as can be appreciated by one of ordinary skill in the art, the training, martensite finishing, and activation temperatures for a shape memory alloy are adjustable, depending on the composition. For example, a slight extra amount of Nickel added to a NiTi alloy composition can change the training temperature from approximately 0° C. to 100° C. The lower member may also comprise a shape memory polymer such as those described in International Publication WO 03/51444.
In certain embodiments, the upper and/or lower members of the devices described herein may also be moveable. For instance, as shown in
As noted above, the upper and lower members may be attached directly to each other at one or more locations as shown in
When present, the central member may be made of a wide variety of materials and may assume many shapes. The central member may be a tubular or coiled structure, including a lumen therethrough, or may be a wire (e.g., a wire or other structure that serves as both central member and guide/pusher wire). The central member may comprise expandable elements, for example as shown in
In certain embodiments, the central member (or an element attached thereto or extending therefrom) is moveable. For instance, as shown in
It will be apparent that the devices described herein can be made in a wide range of sizes in order to fit any size aneurysm. As described above, the operator (surgeon) will typically image the aneurysm and determine the approximate dimensions, for example from dome to neck. The appropriate size device can then be selected and positioned within the aneurysm as described herein.
In certain embodiments, the device is secured in the desired dimensions by employing one or more locking mechanisms are generally included. A variety of locking mechanisms can be used, as shown in
In the variation shown in
Also as shown in
The detachment junction can be positioned anywhere on the device, for example at one or both ends of the device. In certain embodiments, the detachment junction(s) is(are) positioned where the extendable member or upper member is attached to an actuator or locking member. In other embodiments, the detachment junction(s) is(are) positioned at the junction between a pusher tube and the lower member or the central member. In still other embodiments, for example as shown in
In certain embodiments, the severable junction(s) are, an electrolytically detachable assembly adapted to detach by imposition of a current; a mechanically detachable assembly adapted to detach by movement or pressure; a thermally detachable assembly adapted to detach by localized delivery of heat to the junction; a radiation detachable assembly adapted to detach by delivery of electromagnetic radiation to the junction or combinations thereof.
Furthermore, one or more actuators may be included so that an operator can manipulate the shape or position of the device. For example, the moveable members may be attached, either directly or through another element such as a pusher wire, to an actuator. In certain embodiments, the pusher wire both advances the device into the aneurysm and acts as the actuator to adjust the overall dimensions. As noted above, a pusher wire can serve as guide wire and, optionally actuator. For example, the extendable element (60) of
The devices described herein may also comprise additional components, such as co-solvents, plasticizers, coalescing solvents, bioactive agents, antimicrobial agents, antithrombogenic agents, antibiotics, pigments, radiopacifiers and/or ion conductors which may be coated using any suitable method or may be incorporated into the element(s) during production. See, e.g., co-owned U.S. patent application Ser. No. 10/745,911, U.S. Pat. No. 6,585,754 and WO 02/051460, incorporated by reference in their entireties herein.
As noted elsewhere, the location of the device is preferably visible using fluoroscopy. A highly preferred method is to ensure that at least some of the elements making up the device are provided with significant radio-visibility via the placement of a radio-opaque covering on these elements. A metallic coating of a metal having comparatively more visibility, during fluoroscopic use, than stainless steel is preferred. Such metals are well known but include gold and members of the Platinum Group described above.
As noted above, one of more of the elements may also be secured to each other at one or more locations. For example, to the extent that various elements are thermoplastic, they may be melted or fused to other elements of the devices. Alternatively, they may be glued or otherwise fastened. Furthermore, the various elements may be secured to each other in one or more locations.
Methods of Use
The devices described herein are often introduced into a selected site using the procedure outlined below. This procedure may be used in treating a variety of maladies. For instance in the treatment of an aneurysm, the aneurysm itself will be filled (partially or fully) with the devices described herein.
Generally, devices as described above are delivered to an aneurysm via a delivery catheter. It will be apparent that the device is preferably delivered in an undeployed shape, e.g., a tubular shape and that, following deployment, the device assumes a different three-dimensional configuration. The device may be self-configuring (e.g., self-expanding) upon deployment, may require actuation by one or more stimuli and/or may be partially self-configuring and partially shaped by application of one or more stimuli.
Self-configuring materials include shape memory alloys and polymers, described above. Thus, the super-elastic characteristics of these materials allow the device to be deployed in a compressed configuration and upon deployment, to assume its three-dimensional configuration. It is to be understood that the three-dimensional configuration assumed by self-configuring devices may also be shaped further (e.g., changing the distance between lower and upper members) using one or more stimuli described below.
In other embodiments, the device assumes a deployed configuration upon the application of one or more appropriate stimuli. For example, the device may be configured so as to achieve its deployed shape when exposed to body temperature (e.g., temperature of the aneurysm). This can be readily achieved by adjusting the training and activation temperatures to be at, or just below, the temperature of the aneurysm (e.g., approximately 37° C.). The martensite temperature is adjusted to be at a lower temperature. With these temperatures set, the device is heated to, or above the training temperature (austentite phase) and shaped into its desired deployed shape, as described above. Then, the temperature is lowered to, or below, the martensite finish temperature and shaped into its desired undeployed shape. Subsequently, the device is then placed inside the catheter for delivery. The catheter can be constructed of a material that insulates the device from the outside environment and maintains the temperature of the device below the activation temperature. Thus, when the catheter is inserted into the lumen of the blood vessel, the device does not expand into its deployed shape within the catheter.
Other stimuli that can be used to change the configuration of the device upon deployment include application of electromagnetic radiation (light), electricity, mechanical pressure, etc. In certain embodiments, the device self-expands and, subsequently, one or more stimuli are also applied to achieve the desired configuration and/or to lock the device in the desired configuration.
Conventional catheter insertion and navigational techniques involving guidewires or flow-directed devices may be used to access the site with a catheter. The mechanism will be such as to be capable of being advanced entirely through the catheter to place vaso-occlusive device at the target site but yet with a sufficient portion of the distal end of the delivery mechanism protruding from the distal end of the catheter to enable detachment of the implantable vaso-occlusive device. In certain embodiments, the device (e.g., lower member) is attached to the distal end of a retractable sheath (also referred to as a pusher tube). The device may be extended and retracted from the pusher tube (by the actuator) and delivery catheter until the desired configuration is achieved, at which point, the pusher tube is detached from the device and withdrawn along with the delivery catheter.
For use in peripheral or neural surgeries, the delivery mechanism will normally be about 100-200 cm in length, more normally 130-180 cm in length. The diameter of the delivery mechanism is usually in the range of 0.25 to about 2.0 mm. Briefly, occlusive devices (and/or additional components) described herein are typically loaded into a carrier for introduction into a delivery catheter and introduced to the chosen site using the procedure outlined below. This procedure may be used in treating a variety of maladies. For instance, in treatment of an aneurysm, the aneurysm itself may be filled with a device as described herein which cause formation of an emboli and, at some later time, is at least partially replaced by neovascularized collagenous material formed around the implanted vaso-occlusive devices.
A selected site is reached through the vascular system using a collection of specifically chosen catheters and/or guide wires. It is clear that should the site be in a remote site, e.g., in the brain, methods of reaching this site are somewhat limited. One widely accepted procedure is found in U.S. Pat. No. 4,994,069 to Ritchart, et al. It utilizes a fine endovascular catheter such as is found in U.S. Pat. No. 4,739,768, to Engelson. First of all, a large catheter is introduced through an entry site in the vasculature. Typically, this would be through a femoral artery in the groin. Other entry sites sometimes chosen are found in the neck and are in general well known by physicians who practice this type of medicine. Once the introducer is in place, a guiding catheter is then used to provide a safe passageway from the entry site to a region near the site to be treated. For instance, in treating a site in the human brain, a guiding catheter would be chosen which would extend from the entry site at the femoral artery, up through the large arteries extending to the heart, around the heart through the aortic arch, and downstream through one of the arteries extending from the upper side of the aorta. A guidewire and neurovascular catheter such as that described in the Engelson patent are then placed through the guiding catheter. Once the distal end of the catheter is positioned at the site, often by locating its distal end through the use of radiopaque marker material and fluoroscopy, the catheter is cleared. For instance, if a guidewire has been used to position the catheter, it is withdrawn from the catheter and then the assembly, for example including the vaso-occlusive device at the distal end, is advanced through the catheter.
In certain embodiments, the delivery catheter comprises a retractable sheath (or pusher tube) at its distal end that surrounds the device to be delivered. Typically, the retractable distal sheath includes a pull back means operatively connected to the distal sheath. The catheter may be constructed and arranged such that distal end of the sheath does not extend past the distal end catheter. Alternatively, the distal end of the sheath may extend beyond the distal end of the delivery catheter, for example so that is extrudes the device directly into the target site. In certain preferred embodiments, the devices described herein are detachably linked to the distal end of a retractable sheath.
Once the selected site has been reached, the vaso-occlusive device is extruded, for example by retracting the sheath surrounding and mounted to the device. Preferably, the vaso-occlusive device is loaded onto the pusher wire and/or tube via a mechanically or electrolytically cleavable junction (e.g., a GDC-type junction that can be severed by application of heat, electrolysis, electrodynamic activation or other means). Additionally, the vaso-occlusive device can be designed to include multiple detachment points, as described in co-owned U.S. Pat. No. 6,623,493 and 6,533,801 and International Patent publication WO 02/45596. Once detached the devices are held in place by gravity, shape, size, volume, magnetic field or combinations thereof.
After deployment and prior to detachment from the pusher wire and/or pusher tube, it may be preferable to lock the device in the desired configuration. This can be accomplished in any number of ways, for example, using locking elements as shown in
An exemplary deployment scheme is shown in
Modifications of the procedure and vaso-occlusive devices described above, and the methods of using them in keeping with this invention will be apparent to those having skill in this mechanical and surgical art. These variations are intended to be within the scope of the claims that follow.