Surgery – Instruments – Internal pressure applicator
Reexamination Certificate
1998-05-22
2001-09-25
Recla, Henry J. (Department: 3731)
Surgery
Instruments
Internal pressure applicator
Reexamination Certificate
active
06293960
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to devices for interventional therapeutic treatment or vascular surgery for treatment of defects in the vasculature, and more particularly concerns a system and method for detaching occlusion balloons for treatment of aneurysms.
2. Description of Related Art
Vasoocclusive devices are typically placed within the vasculature of the human body by use of 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. Vasoocclusive devices used for these procedures can have a variety of configurations, and are generally formed of one or more elements that are larger in the deployed configuration than when they are within the delivery catheter prior to placement. One anatomically shaped vasoocclusive device that forms itself into a shape of an anatomical cavity such as an aneurysm is made of a preformed strand of flexible material such as a nickel-titanium alloy. One or more of such vasoocclusive members can be wound to form a generally spherical or ovoid shape in a relaxed, expanded state.
Aneurysms have been treated with external surgically placed clips, or using vascular catheters, by detachable vasoocclusive balloons or an embolus generating vasoocclusive device such as one or more vasoocclusive coils. The delivery of such vasoocclusive devices can be accomplished by a variety of means, including via a catheter in which the device is pushed through an opening at the distal end of the catheter by a pusher to deploy the device. The vasoocclusive devices can be produced in such a way that they will pass through the lumen of a catheter in a linear shape and take on a complex shape as originally formed after being deployed into the area of interest, such as an aneurysm.
Some conventional vasoocclusive devices are operated by pulling or jerking the catheter tip from the balloon, thus potentially compromising the position of the implant. One such device provides for an endovascular wire and tip that can be separated from the holding wire mechanically or electrolytically for the formation of thrombus in blood vessels. However, such devices that release the interventional device by mechanically breaking an intermediate section between the catheter tip and balloon can potentially leave broken or jagged ends that can potentially injure the vasculature.
One conventional releasable balloon catheter used to embolize vascular lesions has a tube portion made of a material such as a hydrophilic polymer, located between the catheter and the balloon, that can be broken by torsion of the tube. The tube can be melted by heating the tube, or can be dissolved in the blood when heated, and electrodes are provided for heating the tube. Another conventional technique for separating a balloon from a balloon catheter involves the melting and breaking of a connecting member made from polyvinyl alcohol or trans-polyisoprene between the balloon and the catheter body, when power is supplied to electrodes provided for heating the connecting member. When the connecting member is heated to temperatures of about 70° C. and slight tension is applied, the balloon can be separated from the main catheter body. However, such devices that release the interventional device by melting or dissolving the intermediate section between the catheter tip and balloon can also potentially release undesirable particles of materials into the bloodstream.
There is therefore a need for a precise method of detaching occlusion balloons or other therapeutic interventional devices without compromising the position of the implant, without presenting broken or jagged ends that can potentially injure the vasculature, and without releasing undesirable particles of materials into the bloodstream. It is therefore desirable to provide a method and system for cleanly releasing occlusion balloons from a placement catheter for treatment of aneurysms. The present invention meets these needs.
SUMMARY OF THE INVENTION
Briefly, and in general terms, the present invention provides for an occlusion balloon catheter and a precise system and method of for cleanly releasing an implant such as an occlusion balloon or other occlusion device from the occlusion balloon catheter for use in interventional therapy and vascular surgery, and which is adapted to be inserted into a portion of a vasculature for treatment of a body vessel such as an aneurysm without compromising the position of the implant.
In a presently preferred aspect of the invention, the occlusion balloon catheter comprises an elongated tubular catheter body or shaft having a fluid lumen in fluid communication with a detachable occlusion balloon for inflation of the occlusion balloon. Mounting means are also provided for detachably mounting an occlusion balloon to a tubular catheter body and for detaching the occlusion balloon for deployment when a desired placement within an aneurysm to be treated and out of a parent vessel is achieved. The mounting means preferably comprises a collar of shape memory material disposed on the distal tip of the tubular catheter body and connecting the occlusion balloon to the tubular catheter body. In one presently preferred embodiment, the occlusion balloon comprises a valve permitting the inflation of the occlusion balloon through the inflation lumen of the occlusion balloon catheter, and sealing the occlusion balloon once the occlusion balloon is inflated, and the collar of shape memory material clamps onto the valve of the occlusion balloon. In one aspect, the external surface of the valve is grooved to improve gripping of the shape memory collar onto the occlusion balloon valve. The shape memory collar can be heated to thereby assume a configuration disconnecting the occlusion balloon and the placement catheter body. In a currently preferred embodiment, a fiber optic can be threaded through the catheter shaft and connected to an optical light source for conducting light energy to the collar to heat the collar and to thereby induce the collar to assume an enlarged configuration to detach the occlusion balloon from the placement collar.
In a presently preferred embodiment of the method of using the invention, the occlusion balloon catheter is placed within a guiding catheter. The guiding catheter is then placed within the vasculature so that the distal opening of the guiding catheter extends into an aneurysm or other deformation to be treated. A fiber optic pusher is then used to expel the device into the aneurysm. In a presently preferred aspect of the invention, the fiber optic is threaded through the occlusion balloon catheter after the balloon is inflated and ready for detachment and up to the shape memory collar that can be heated by the energy transmitted through the optical fiber to cause the shape memory material to assume a shape that releases the balloon from the occlusion balloon catheter. In other presently preferred embodiments, the balloon can be released by other means, such as thermo-mechanical, electromagnetic or electro-dissolution of the coupling between the device and the pusher.
The method of the invention for closing and occluding an opening of an aneurysm from a parent blood vessel accordingly thus comprises the steps of attaching an occlusion balloon to the distal end of a occlusion balloon catheter, enclosing the occlusion balloon catheter and occlusion balloon in a lumen of a guiding catheter, with the occlusion balloon catheter proximal of the occlusion balloon, positioning the guiding catheter so that the distal opening of the guiding catheter is in the opening between the aneurysm and the parent blood vessel, pushing the occlusion balloon into the aneurysm by extending the occlusion balloon catheter towards the distal end of the guiding catheter, inflating the occlusion balloon with inflation fluid conducted through the occlusion balloon catheter, and disconnecting the occlusion balloon from the occlu
Fulwider Patton Lee & Utecht LLP
Ho (Jackie)Tan-Uyen T.
Micrus Corporation
Recla Henry J.
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