Abstract:
An aneurysm embolization device and deployment system for use in occluding the flow of blood at a preselected position within a vessel of the human body comprising a headpiece and a plurality of spherical members linked together with a central connecting member, which, when deployed the embolization device occludes the flow of blood in a high volume or wide neck aneurysm.

Description:
This continuation patent application claims the benefit of U.S. patent application Ser. No. 10/141,411 filed on May 8, 2002, which is a nonprovisional patent application of U.S. patent application Ser. No. 60/298,324 filed on Jun. 14, 2001. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a medical apparatus and method for occluding the flow of blood at a preselected position within a vessel of the human body, and more particularly, relates to an aneurysm embolization device for filling a high volume or wide neck aneurysm and a deployment system for releasing the embolization device within the aneurysm. 
     2. Description of the Prior Art 
     For many years physicians have been placing various devices within a blood vessel of the human body in order to treat an aneurysm by promoting thrombus formation. Such devices include balloons, coils, fiber retainers, multi-element anchors, and micropellets. Balloons are introduced into an aneurysm using a deployment catheter and then inflated within the aneurysm. The balloon prevents the flow of blood within the parent vessel from entering the aneurysm. 
     Another type of occluding device is an embolic coil. Embolic coils may take the form of helically wound coils, randomly wound coils, coils wound within other coils, or many other coil configurations. These coils are generally formed of metallic materials, such as platinum, gold, and tungsten, or alloys of these metals. Often times, several coils need to be placed within an aneurysm in order to occlude the flow of blood. 
     Furthermore, a retainer which holds at least one fiber bundle can occlude the flow of blood. The retainer can take the form of a cube, sphere, cylinder, coil, oval, or other similar shape. The thrombogenic fibers are longer than the retainer and can be made of silk, cotton, nylon, or polyurethane. These fiber bundles occlude the flow of blood in a vessel. This device is primarily used in small vessels of the vasculature. 
     Also, a multi-element occlusion device can stop the flow of blood in a vessel. This device has two or more elements connected by at least one metallic or nonmetallic fiber. The elements can be particles or coils with various sizes and shapes. The device is deployed with a catheter and flows downstream until the anchoring element lodges against the vessel wall. The multiple elements connected to the anchor help create deep occlusion. This device cuts off the flow of blood in a vessel and reduces the risk of continued canalization within the vessel. 
     Finally, micropellets are cylindrical members formed from a biocompatible foam or gel material. Several micropellets can be linked together with a carrier wire and when the micropellets are soaked in a fluid, they expand to fill an aneurysm. The swelled micropellets occlude the flow of blood and become fixed within the aneurysm. 
     Balloons, coils, fiber retainers, multi-element anchors, and micropellets are devices beneficial in treating aneurysms. However, the present invention is useful in treating large aneurysms or wide neck aneurysms. The present invention is an embolization device which occludes the flow of blood in an aneurysm, reduces the risk of becoming dislodged, allows blood to continue flowing through the parent vessel, and allows for retrieval or realignment. 
     SUMMARY OF THE INVENTION 
     In accordance with one aspect of the present invention, an aneurysm embolization device and deployment system is provided for use in placing the aneurysm embolization device at a preselected position within a vessel of the body. The deployment system includes a deployment catheter formed of a material which is sufficiently flexible to pass through the vasculature of the body. The proximal section of the catheter has substantially no radial expansion when fluid pressure is applied to the lumen of the catheter. The distal section of the catheter expands radially when fluid pressure is applied. The deployment system also includes a headpiece. The distal section of the headpiece is hemispherical in shape while the proximal section of the headpiece is cylindrical and is disposed within the lumen of the deployment catheter. Furthermore, the deployment system includes a central connecting member. The central connecting member is a flexible fiber which is attached at one end to the headpiece. The deployment system also includes a spherical member. The spherical member is a small diameter ball and is disposed about the central connecting member. Finally, the proximal section of the deployment catheter includes a connector. The connecter is adapted for a fluid pressure generating device and is used for applying fluid pressure to the lumen of the deployment catheter causing the distal section of the catheter to expand radially thereby releasing the headpiece and deploying the aneurysm embolization device. 
     In accordance with another aspect of the present invention, an aneurysm embolization device is provided for use in occluding the flow of blood at a preselected position within a vessel of the human body. The aneurysm embolization device includes a headpiece. The distal section of the headpiece is hemispherical in shape while the proximal section of the headpiece is cylindrical and is disposed within a deployment catheter. The aneurysm embolization device also includes a central connecting member. The central connecting member is a flexible fiber which is attached at one end to the headpiece. Finally, the aneurysm embolization device includes a spherical member. The spherical member is a small diameter ball and is disposed about the central connecting member. 
     In accordance with a similar aspect of the present invention, the headpiece and spherical member are made of a polymer or metallic material. 
     In accordance with a similar aspect of the present invention, the headpiece and spherical member are made of a metallic material. 
     In accordance with a similar aspect of the present invention, the central connecting member takes the form of a shape memory wire. After the aneurysm embolization device is deployed within the vasculature of the body, the wire tends to assume a predetermined configuration. 
     In accordance with another similar aspect of the present invention, the central connecting member takes the form of a stretchable fiber. 
     In accordance with a similar aspect of the present invention, the headpiece includes a pocket which takes the form of a concave indentation on the headpiece at a position where the central connecting member attaches to the headpiece. As a result, the central connecting member can coil up into the pocket during deployment. 
     In accordance with another similar aspect of the present invention, the spherical member includes a pocket which takes the form of a concave indentation on the spherical member at a position where the central connecting member attaches to the spherical member. As a result, the central connecting member can coil up into the pocket during deployment. 
     In accordance with a similar aspect of the present invention, the spherical member includes a plurality of filaments which are attached generally radial to the spherical member. The filaments enhance the occlusive effect of the spherical member. 
     In accordance with another aspect of the present invention, the spherical member includes a time-released adhesive on the periphery of the spherical member. The adhesive enhances the occlusive effect of the spherical member. 
     In accordance with another aspect of the present invention, the aneurysm embolization device and deployment system includes six spherical members. 
     In accordance with another aspect of the present invention, a method is provided for placing an aneurysm embolization device at a pre-selected position within a vessel. The method includes providing a delivery catheter having an elongated flexible tube and introducing the deliver catheter into the vasculature of the human body. The method also includes providing a deployment system having a deployment catheter. The proximal section of the catheter exhibits the characteristic of having substantially no radial expansion when fluid pressure is applied to the lumen of the catheter. The distal section of the catheter exhibits the characteristic that, when fluid pressure is applied to the lumen of the catheter the distal section of the catheter expands radially. The method further includes providing an aneurysm embolization device having a headpiece disposed within the deployment catheter. The aneurysm embolization device also includes a central connecting member which takes the form of a flexible fiber. The proximal end of the connecting member is attached to the headpiece. Finally, the embolization device includes a spherical member which takes the form of a small diameter ball. The spherical member is disposed about the central connecting member. The method further includes introducing the deployment system and the aneurysm embolization device into the delivery catheter and aligning the aneurysm embolization device with the pre-selected position within the vessel. The method finally includes applying fluid pressure to the deployment catheter causing the distal section of the deployment catheter to expand radially thereby releasing the aneurysm embolization device. 
     These aspects of the invention and the advantages thereof will be more clearly understood from the following description and drawings of the preferred embodiment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an enlarged, partially sectioned view of an aneurysm embolization device and deployment system where the aneurysm embolization device is disposed within a deployment catheter of the deployment system; 
         FIG. 2  is an enlarged perspective view showing an aneurysm embolization device with a headpiece, six spherical members linked to the headpiece with a central connecting member, and filaments attached to the spherical members; 
         FIG. 3  is an enlarged, partially sectioned view of the aneurysm embolization device disposed within the deployment catheter and being transported through a delivery catheter; 
         FIG. 4  is an enlarged, partially sectioned view showing the aneurysm embolization device being positioned within a high volume aneurysm; 
         FIG. 5  is an enlarged, partially sectioned view showing radial expansion of the distal section of the deployment catheter thereby releasing the aneurysm embolization device; and, 
         FIG. 6  is an enlarged, partially sectioned view of the aneurysm embolization device deployed within the high volume aneurysm causing the flow of blood within the aneurysm to occlude. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIG. 1  illustrates an aneurysm embolization device  10  and deployment system  12  which includes a syringe  14  coupled to the proximal section  16  of a deployment catheter  18 . The syringe  14  includes a threaded piston  20  which is controlled by a handle  22  for infusing fluid into a lumen  24  of the deployment catheter  18 . The aneurysm embolization device  10  is disposed within the lumen  24  of the distal section  26  of the deployment catheter  18 . Also, the deployment catheter  18  includes a winged hub  28  which aides in the insertion of the deployment catheter  18  into the vasculature of the human body. 
       FIG. 2  illustrates an aneurysm embolization device  10  which includes a headpiece  30 , six spherical members  32 , and a central connecting member  34  linking the headpiece  30  and spherical members  32  together. Preferably, the length of the aneurysm embolization device  10  may range from about 0.102 inches to about 0.32 inches with a preferred length of approximately 0.148 inches. The spherical members  32  are made of a polymer material, but may be made of other biocompatible materials like stainless steel or platinum. Whether made of a polymer or metallic material, the spherical members  32  are not expandable (non-expanding) so that the aneurysm embolization device  10  can be retrieved or realigned. Preferably, the diameter of a spherical member  32  may range from about 0.012 inches to about 0.020 inches. In the preferred embodiment, the diameter of a spherical member  32  is approximately 0.016 inches. The spherical members  32  may be molded around or bonded to the central connecting member  34 . The ball-like shape of the spherical members  32  allows the aneurysm embolization device  10  to flex and assume complex configurations thereby substantially filling a high volume aneurysm. The central connecting member  34  may be made of Nitinol which is a shape memory material. The connecting member  34  may also be made of other materials like stainless steel, platinum, or a polymer. Preferably, the length of the central connecting member  34  between the spherical members  32  may range from about 0.0015 inches to about 0.015 inches. In the preferred embodiment, the length of the central connecting member  34  between the spherical members  32  is approximately 0.006 inches. The headpiece  30  is made of a polymer material, but may be made of other biocompatible materials like stainless steel or platinum. Preferably, the length of the headpiece  30  may range from about 0.012 inches to about 0.020 inches. In the preferred embodiment, the length of the headpiece  30  is approximately 0.016 inches. The distal section  36  of the headpiece  30  is hemispherical in shape and has a radius generally equal to one half the length of the headpiece  30 . In the preferred embodiment, the radius of the distal section  36  of the headpiece  30  is approximately 0.008 inches. The proximal section  38  of the headpiece  30  is cylindrical in shape and has a radius generally equal to the radius of the distal section  36  of the headpiece  30 . Filaments  40  are molded into or bonded with the spherical members  32 . The filaments  40  are made of nylon but may also be made of acrylic or a polymer. Preferably, the length of the filaments  40  may range from about 0.003 inches to about 0.010 inches. In the preferred embodiment, the length of the filaments  40  is approximately 0.005 inches. The filaments  40  may cover the surface of a spherical member  32  from 0 percent to 50 percent; there is a coverage area of about 10 percent in the preferred embodiment. 
       FIG. 3  illustrates the deployment catheter  18  with the aneurysm embolization device  10  during transportation through a delivery catheter  42  positioned in a vessel  44 . The headpiece  30  is tightly held within the lumen  24  of the deployment catheter  18 . In this position, the headpiece  30  serves to provide a fluid-tight seal at the distal section  26  of the deployment catheter  18 . 
     Preferably, the proximal section  16  of the deployment catheter  18  is formed of Pebax material having a durometer in a range of about 62 D to 75 D. The proximal section  16  is sufficiently flexible to transverse the vasculature of the human body, but is sufficiently rigid such that, when fluid pressure of approximately 90 to 450 psi is applied to the lumen  24  of the deployment catheter  18  there is very little, if any, radial expansion of the proximal section  16 . The distal section  26  of the deployment catheter  18  is preferably formed of polymer material with a relatively low durometer which exhibits the characteristic that, when fluid pressure of approximately 90 to 450 psi is applied to the lumen  24  of the deployment catheter  18  the distal section  26  expands radially thereby releasing the aneurysm embolization device  10 . The distal section  26  of the deployment catheter  18  is preferably formed of Pebax material having a durometer of between 25 D and 55 D with a durometer of 40 D being the preferred durometer. 
       FIGS. 4 and 5  illustrate the deployment catheter  18  with the aneurysm embolization device  10  being positioned within an aneurysm  46 . More particularly, as shown in  FIG. 5 , when fluid pressure is applied to the lumen  24  of the deployment catheter  18  the relatively low durometer distal section  26  of the deployment catheter  18  expands radially. As the distal section  26  of the deployment catheter  18  continues to expand radially there comes a point in which the headpiece  30  becomes disengaged from the lumen  24  of the deployment catheter  18  and the aneurysm embolization device  10  deploys within the aneurysm  46 . 
     As illustrated in  FIG. 6 , when the aneurysm embolization device  10  has been released from the deployment catheter  18 , the deployment catheter  18  may be withdrawn, leaving the aneurysm embolization device  10  positioned within the aneurysm  46  to occlude the flow of blood. 
     A novel system has been disclosed in which an aneurysm embolization device is delivered precisely to an aneurysm. Although a preferred embodiment of the invention has been described, it is to be understood that various modifications may be made by those skilled in the art without departing from the scope of the present invention. For example, there are many variations as to the number of spherical members and diameter of the spherical members. The number of spherical members and size of the spherical members would depend on what the physician requires for treating a particular aneurysm. 
     In an alternative construction, the aneurysm embolization device could include pockets on the spherical members. The pockets may take the form of concave indentations positioned on the spherical member where the central connecting member attaches to the spherical member. During deployment of the aneurysm embolization device, the central connecting member can coil up into the pockets on the spherical member. 
     Furthermore, the aneurysm embolization device could include perpendicular wire branches between the spherical members with their own set of spherical members. These perpendicular branches and additional spherical members could further enhance the occluding effect of the aneurysm embolization device. 
     In another alternative construction, the aneurysm embolization device could include spherical members which are free floating along the central connecting member between the headpiece and most distal spherical member. These free floating spherical members could have channels through their centers which would allow the spherical members to slide along the central connecting member thereby allowing the aneurysm embolization device to assume complex configurations to fill an aneurysm. 
     These and other modifications would be apparent to those having ordinary skill in the art to which this invention relates and are intended to be within the scope of the claims which follow.