Surgery – Instruments – Internal pressure applicator
Reexamination Certificate
2000-08-17
2002-03-26
Truong, Kevin (Department: 3731)
Surgery
Instruments
Internal pressure applicator
C606S108000
Reexamination Certificate
active
06361547
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a medical device for placing an embolic coil at a preselected location within a vessel of the human body, and more particularly, relates to a catheter having a distal tip for retaining the embolic coil in order to transport the coil to a preselected position within the vessel and a control mechanism for releasing the embolic coil at the preselected position.
2. Description of the Prior Art
For many years flexible catheters have been used to place various devices within the vessels of the human body. Such devices include dilatation balloons, radiopaque fluids, liquid medications and various types of occlusion devices such as balloons and embolic coils. Examples of such catheter devices are disclosed in U.S. Pat. No. 5,108,407, entitled “Method And Apparatus For Placement Of An Embolic Coil”; U.S. Pat. No. 5,122,136, entitled, “Endovascular Electrolytically Detachable Guidewire Tip For The Electroformation Of Thrombus In Arteries, Veins, Aneurysms, Vascular Malformations And Arteriovenous Fistulas.” These patents disclose devices for delivering embolic coils to preselected position within vessel of the human body in order to treat aneurysms or alternatively to occlude the blood vessel at the particular location.
Coils which are placed in vessels may take the form of helically wound coils, or alternatively, may be random wound coils, coils wound within other coils or many other such coil configurations. Examples of various coil configurations are disclosed in U.S. Pat. No. 5,334,210, entitled, “Vascular Occlusion Assembly; U.S. Pat. No. 5,382,259, entitled, “Vasoocclusion Coil With Attached Tubular Woven Or Braided Fibrous Coverings.” Embolic coils are generally formed of a radiopaque metallic materials, such as platinum, gold, tungsten or alloys of these metals. Often times several coils are placed at a given location in order to occlude the flow of blood through the vessel by promoting thrombus formation at the particular location.
In the past, embolic coils have been placed within the distal end of the catheter and when the distal end of the catheter is properly positioned the coil may then be pushed out of the end of the catheter with, for example a guidewire, to release the coil at the desired location. This procedure of placement of the embolic coil is conducted under fluoroscopic visualization such that the movement of the coil through the vasculature of the body may be monitored and the coil may be placed in the desired location. With these placements systems there is very little control over the exact placement of the coil since the coil may be ejected to a position some distance beyond the end of the catheter. As is apparent, with these latter systems, when the coil has been released from the catheter it is difficult, if not impossible, to retrieve the coil or to reposition the coil.
Numerous procedures have been developed to enable more accurate positioning of coils within a vessel. Still another such procedure involves the use of a glue or solder for attaching the embolic coil to a guidewire which, is in turn, placed within a flexible catheter for positioning the coil within the vessel at a preselected position. Once the coil is at the desired position, the coil is restrained by the catheter and the guidewire is pulled from the proximal end of the catheter to thereby cause the coil to be detached from the guidewire and released from the catheter system. Such a coil positioning system is disclosed in U.S. Pat. No. 5,263,964, entitled, “Coaxial Traction Detachment Apparatus And Method.”
Another coil positioning system utilizes a catheter having a socket at the distal end of the catheter for retaining a ball which is bonded to the proximal end of the coil. The ball, which is larger in diameter than the outside diameter of the coil, is placed in a socket within the lumen at the distal end of the catheter and the catheter is then moved into a vessel in order to place the coil at a desired position. Once the position is reached, a pusher wire with a piston at the end thereof is pushed distally from the proximal end of the catheter to thereby push the ball out of the socket in order to thereby release the coil at the desired position. Such a system is disclosed in U.S. Pat. No. 5,350,397, entitled, “Axially Detachable Embolic Coil Assembly.” One problem with this type of coil placement system which utilizes a pusher wire which extends through the entire length of the catheter and which is sufficiently stiff to push an attachment ball out of engagement with the socket at the distal end of the catheter is that the pusher wire inherently causes the catheter to be too stiff with the result that it is very difficult to guide the catheter through the vasculature of the body.
Another method for placing an embolic coil is that of utilizing a heat releasable adhesive bond for retaining the coil at the distal end of the catheter. One such system uses laser energy which is transmitted through a fiber optic cable in order to apply heat to the adhesive bond in order to release the coil from the end of the catheter. Such a method is disclosed in U.S. Pat. No. 5,108,407, entitled, “Method And Apparatus For Placement Of An Embolic Coil.” Such a system also suffers from the problem of having a separate element which extends throughout the length of the catheter with the resulting stiffness of the catheter.
SUMMARY OF THE INVENTION
The present invention is directed toward a vascular occlusive coil deployment system for use in placing an embolic coil at a preselected site within a vessel which includes an elongated, flexible catheter having a distal tip for retaining the coil so that the coil may be moved to the preselected position within the vessel. The catheter has a lumen which extends therethrough the length of the catheter and also includes a distal end which is formed of a material having a durometer such that when a fluid pressure of about 300 pounds per square inch (psi) is applied to the interior of the catheter, the walls of the distal tip expand outwardly, or radially, to thereby increase the lumen of the distal tip of the catheter. The proximal end of the embolic coil is placed into the lumen of the distal tip of the catheter and is retained by the distal tip of the catheter. A hydraulic injector, such as a syringe, is coupled to the proximal end of the catheter for applying a fluid pressure to the interior of the catheter. When the coil is placed at a desired position within a vessel, fluid pressure is then applied to the interior of the catheter by the hydraulic injector to thereby cause the walls of the distal tip to expand outwardly to thereby release the coil for placement in the vessel.
In accordance with another aspect of the present invention, the flexible catheter is comprised of a proximal section and a relatively short distal section. The proximal section is formed of a material which is sufficiently flexible to be passed through the vasculature of the human body and is of a durometer which essentially resists outward expansion when a fluid pressure on the order of about 300 psi is applied to the interior of the catheter. The distal section of the catheter is formed of a material which is also sufficiently flexible to be passed through the vasculature of the body, yet is of a durometer which is significantly lower than the durometer of the proximal section and exhibits the property of expanding outwardly, or radially, when such a fluid pressure is applied to the interior of the catheter to thereby permit the release of the embolic coil.
In accordance with still another aspect of the present invention, the distal section of the catheter has a durometer in a range of between about 25 D and 55 D.
In still another aspect of the present invention, the embolic coil is comprised of a helical coil having a proximal end, a distal end, and a lumen extending therethrough. A seal plug is disposed within the lumen of the proximal end of the coil in fluid-tight engagement. The proximal end of the
Collins Henry W.
Cordis Corporation
Truong Kevin
LandOfFree
Embolic coil hydraulic deployment system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Embolic coil hydraulic deployment system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Embolic coil hydraulic deployment system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2881283