Patent Application
20080269721
This invention generally relates to medical devices that are navigable through body vessels of a human subject. More particularly, this invention relates to tubular devices having a spiral section and radiopaque marker and methods of making the same.
A number of medical procedures require the introduction of tubing to a body vessel. For example, vessel defects, such as blockages and stenoses, within the human vasculature system are often treated by the intraluminal delivery of treatment fluids or implants, such as expandable stents and embolic coils. Implants can take any of a number of forms and may be delivered to a diseased site in a number of manners. According to one known method of delivering a medical implant, the distal end of a flexible catheter is positioned adjacent to a target site of a body vessel, such as an aneurysm. Once the catheter is properly positioned, a delivery/detachment system is passed through a lumen of the catheter until a distal end of the delivery system exits the distal end of the catheter in the area of the target site. An implant, such as an embolic coil, carried at the distal end of the delivery/detachment system is thereafter released to the diseased site.
The path to the target site is typically tortuous, so the catheter is preferably relatively flexible to allow it to pass through the vasculature to the desired site. Conversely, the catheter may be required to pass through constricted vessels, so it is also desirable for it to exhibit good column strength. When the catheter has been properly positioned, the delivery system must follow the path defined by the catheter, so the delivery system also preferably has similar characteristics of flexibility and good column strength. In particular, it is generally preferred for the delivery system to exhibit column strength and good pushability, particularly at its proximal end, to allow the delivery system to be pushed through the catheter, and relatively flexible especially at a distal end, to allow the delivery system to follow the path defined by the catheter.
It may also be preferred to provide the catheter and/or the delivery system with one or more radiopaque markers, typically positioned at the distal end thereof, to aid in the positioning and deployment of the implant to a target location within a body vessel. The implant itself may also be provided with a radiopaque marker. Radiopaque markers facilitate the positioning of the implant within a blood vessel by allowing a physician to determine the exact location and orientation of the catheter, delivery system, and/or implant under x-ray or fluoroscopy. These markers are typically formed of a radiopaque material such as tantalum, zirconium, gold, platinum, iridium, tungsten, or a combination thereof.
For a radiopaque marker applied to certain medical device components, an important objective may be to have the marker be substantially flush with an outer surface of the component. For example, as described previously, an implant delivery system is pushed through a catheter to deliver an implant to a target location within a body vessel. If the distal end of the delivery system has a radiopaque marker extending beyond the outer surface of the system, it creates a projecting discontinuity or “ledge,” which increases the risk that the projecting marker will promote potentially undesirable contact with a guiding catheter, other component of the system, a body vessel wall or the like. In the case of a marker band that imparts a projecting discontinuity (which can be circumferential in the case of a band that extends the full circumferential extent of the device), there is a potential risk of some adverse effect, no matter how minimal, or of interference with a fully smooth operation of the diagnostic or treatment system, such as by snagging upon a catheter as it is pushed therethrough to the target location. It will be appreciated by those of ordinary skill in the art that other medical device components may similarly benefit from a radiopaque marker that is flush with the outer surface of the component.
A general aspect or object of the present invention is to provide a medical device system that includes a component having a radiopaque marker which avoids the creation of a “ledge” that may adversely affect performance of the component within an introducer or catheter through which the component is administered.
Another aspect or object of this invention is to provide a method of affixing a radiopaque marker to a medical device component so as to avoid the creation of a “ledge” that may adversely affect performance of that component within an introducer or catheter through which the component is administered.
Other aspects, objects and advantages of the present invention, including the various features used in various combinations, will be understood from the following description according to preferred embodiments of the present invention, taken in conjunction with the drawings in which certain specific features are shown.
In accordance with one embodiment or aspect of the present invention, a component of an interventional medical device system operable while within a body vessel includes an elongated introducer within which is positioned a pusher that is provided with a generally hollow tubular portion. The tubular portion includes a spiral ribbon. An arcuate radiopaque marker overlays at least a portion of the spiral ribbon. An outer surface of the radiopaque member is substantially flush with an outer surface of the tubular portion and/or the spiral ribbon immediately proximal or immediately distal the radiopaque marker.
According to another aspect or embodiment of the present invention, a method of creating a component of an interventional medical device system that includes an elongated introducer and a pusher component therewithin, the system being operable while within a body vessel is provided that includes providing a tubular member and a cutting device. The cutting device is operated to create a helically oriented cut section in the tubular member. A pre-assembly radiopaque marker member then is positioned over at least a portion of the cut section. The radiopaque marker member is crimped onto the cut section such that an outer surface of the thus assembled radiopaque marker is substantially flush with an outer surface of the tubular portion and/or the cut section immediately proximal or immediately distal the radiopaque marker.
According to yet another aspect or embodiment of the present invention, a method of creating a component of an interventional medical device system that includes an elongated introducer and a pusher therewithin, the system being operable while within a body vessel is provided that includes providing a tubular member and an elongated filament. At least a portion of the filament is wound to create a helically wound section. A pre-assembly radiopaque marker member then is positioned over at least a portion of the wound section. The radiopaque marker member is crimped onto the wound section such that the outer surface of the thus formed radiopaque marker is substantially flush with an outer surface of the tubular portion and/or the wound section immediately proximal or immediately distal the radiopaque marker.
Special application for the present invention has been found for tubular portions of medical device guidewires, catheters, microcathers, fine-bore guiding cathers, and embolic coil/implant delivery, detachment or retrieval systems. Suitable medical procedure applications are illustrated in U.S. patent application Ser. Nos. 11/461,231 and 11/461,245 to Mitelberg et al., filed Jul. 31, 2006, which are hereby incorporated herein by reference. However, the present invention is also applicable to tubular components of other devices adapted for movement through body lumens, so it will be understood that certain embodiments of the products and methods described herein are not limited to particular medical devices or particular surgical applications.
As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriate manner.
The system 10 includes a pusher member 12, which is an exemplary medical device component according to the present invention. The pusher member 12 is a generally hollow tube or tubular structure used to push an embolic coil 14 through an introducer or catheter 16 of the system 10. When used herein, the terms “tubular” and “tube” are to be construed broadly and are not limited to a structure that is a right cylinder or strictly circumferential in cross-section or of a uniform cross-section throughout its length. For example, the pusher member 12 is shown as a substantially right cylindrical structure. However, the pusher member 12 may have a tapered or curved outer surface without departing from the scope of the present invention.
The pusher member 12 includes a generally hollow tubular portion 18, illustrated in
According to one method of forming the cut section, a generally hollow tubular member and a cutting device are provided. The nature of the cutting device depends on the material of the hollow tubular member, but a laser is a suitable cutting device for use with a metallic tubular member, such as a hypotube. In the case of a stainless steel tubular member suitable for use in delivering a neurovascular implant, i.e. a tubular member having an outer diameter no greater than 0.025 inch, the laser may be adapted to provide a kerf in the range of about 0.0005-0.0015 inch (preferably 0.001 inch). The cutting device is operated to create a cut in the tubular member. At least one of the tubular member and the cutting device is moved in a substantially helical path with respect to the other to form a helical cut in the tubular member.
The helical movement of the above method may be accomplished in a variety of ways, such as by rotating the cutting device about the tubular member or by fixing the cutting device and rotating the tubular member on a mandrel. The helical movement may also be achieved by moving both the tubular member and the cutting device, such as by rotating the tubular member while moving the cutting device axially with respect to the rotating tubular member.
In another embodiment, the spiral ribbon of a component according to the present invention may be formed by a winding operation. In such a method, at least a portion of an elongated filament, such as a metallic flat ribbon wire, is wound so as to assume a generally hollow tubular shape. It may be preferred to wind the filament in a helical direction about a substantially cylindrical structure, such as a mandrel, to improve the resulting shape of the spiral ribbon. A spiral ribbon so formed is alternatively referred to herein as a “wound section” of the tubular portion.
As shown in
The radiopaque marker originates as a pre-assembly radiopaque marker member 30a, which is movable or transformable from a disconnected or pre-assembly condition, shown generally in
Preferably, a pre-assembly radiopaque marker member 30a, which is in a disconnected condition, is positioned over at least a portion of the spiral ribbon 22 (
In one embodiment, illustrated in
As shown in
When the ends of the radiopaque marker 30 are substantially flush with the sections of the tubular portion 18 immediately adjacent thereto, there will be no regions of projecting discontinuity or “ledges” created. If the component is a pusher member of an embolic coil delivery/detachment system, as shown in
It will be understood that the embodiments of the present invention which have been described are illustrative of some of the applications of the principles of the present invention. Numerous modifications may be made by those skilled in the art without departing from the true spirit and scope of the invention, including those combinations of features that are individually disclosed or claimed herein.
