Steerable catheter with rapid exchange lumen

A medical device for advancement over a guidewire includes a number of lumens therein including a working channel lumen, one or more control wire lumens, and a guidewire lumen. A flexible support within the device includes a number of interlocking elements that resist longitudinal compression, transfer rotational torque, and can bend side to side. The flexible support also includes a slot that is aligned with the guidewire lumen. An outer jacket includes a perforation, slot, slit, or thinned area that is aligned with the slot in the support member and the guidewire lumen in order to allow a device such as a guidewire to be removed from the guidewire lumen and through the support member.

TECHNICAL FIELD

The disclosure relates to medical devices in general, in particular to steerable devices for use with a guidewire.

BACKGROUND

As an alternative to performing more invasive medical procedures, many physicians are performing examinations and/or therapeutic procedures in vivo with catheters or other devices. Such devices are generally routed from outside the patient to an area of interest through a small opening in the skin or through a body orifice. Such devices often include one or more lumens by which additional tools, medicines, and the like, can be delivered to a site in order to perform a desired task.

In order to route a catheter to its desired location, many procedures require the use of a guidewire. The guidewire is first advanced by the physician to the point of interest and then left in place to serve as a rail over which additional devices can be routed in order to guide them to the desired location.

FIG. 1shows an example of a conventional guidewire10and a catheter20positioned over the guidewire. In many procedures, it is desirable to leave the guidewire in place while one catheter is exchanged for another. Therefore, the proximal end12of the guidewire10is fixed while the catheter20is removed from the patient. In order to maintain a handle on the proximal end12of the guidewire10, it is necessary that the portion of the guidewire that remains outside the patient be longer than the length of the catheter20. Therefore, a catheter/guidewire system such as that shown inFIG. 1, requires the use of long guidewires that can be cumbersome to manipulate and can clutter an operating room.

To address the issues associated with changing catheters over long guidewires, many catheters include so-called “rapid exchange” lumens. As shown inFIG. 2, a rapid exchange catheter30includes an opening32on the sheath of a catheter and a slot34that extends along the length of the catheter through which a guidewire40can be pulled. To exchange the catheter30for another device while maintaining the position of the guidewire40in the body, the catheter30is stripped off the guidewire40by pulling it through the slot34. A new catheter or device can be routed over the guidewire40by inserting the proximal end of the guidewire40into an opening of a guidewire lumen at the distal end of the new device and advanced such that the proximal end of the guidewire exits the opening32. The opening32may be positioned towards the proximal end of the catheter or may be located more towards the distal end.

While rapid exchange catheters and devices have been developed for many procedures, they have not been adapted for use with steerable catheters or catheters that are required to transmit torque from the proximal to the distal end of the catheter. Such devices often include a wire braid to increase column strength and transfer rotational torque. However, cutting this braid to allow the removal of the guidewire results in the braid becoming unraveled or frayed in a manner that can compromise the construction and performance of the catheter.

Because steerable devices are becoming increasingly used to navigate through the patient's body, there is a need for a mechanism to incorporate the advantages of a rapid exchange guidewire lumen with devices that are steerable and/or can transmit torque.

SUMMARY

To address the problems discussed above, the present disclosure is directed to a rapid exchange type medical device that can be steered within the body using one or more control wires and/or can transmit torque from the proximal end to the distal end.

In one embodiment, the device is a catheter that includes an outer jacket and a support member positioned therein that resists longitudinal compression and transfers rotational torque from the proximal end of the catheter to the distal end. In one embodiment, the support member has a number of aligned rings that are joined together with hinges. In addition, the support member includes a longitudinally extending slot along a portion of the circumference of the rings. The slot in the support member is aligned with a guidewire lumen in the catheter and a corresponding slot, perforation, or other opening in the outer jacket through which a guidewire can be removed.

DETAILED DESCRIPTION

As will be described in further detail below, the present disclosure is directed to a rapid exchange catheter or other medical device that can be steered within a patient and/or can transmit rotational torque along its length. Although the embodiments disclosed are configured as catheters, it will be appreciated that the device is useful in any medical instrument that is designed to be used with a guidewire or other tool to be removed from an outer sheath.FIG. 3illustrates one embodiment of a steerable catheter including a rapid exchange guidewire lumen. The catheter50has a distal tip52with openings to a number of lumens within the catheter. In the example shown, the distal tip52includes an opening54to a working channel lumen and an opening56to a second lumen, which may be used to route a fiber optic bundle or other tool within the catheter. In addition, the distal tip includes an opening to a guidewire lumen58that allows the rapid exchange of the catheter50over a guidewire as will be explained in further detail below.

As better shown inFIG. 4, a flexible support60extends from the distal tip52towards the proximal end of the catheter50. The flexible support60serves to increase the column strength of the catheter50and to transfer torque along its length. In one embodiment, the flexible support60has a number of axially aligned rings62,64,66, etc., each having an outer edge that extends substantially around the circumference of the catheter50. Adjacent rings, for example, ring62and ring64, are secured to one another by one or more hinges70. Between each adjacent pair of rings, the hinges70are staggered. For example, in one embodiment, a pair of rings may be secured together with four hinges positioned at 0°, 90°, 180°, and 270° around the circumference of the rings. An adjacent pair of rings may be secured together with hinges positioned at 45°, 135°, 225°, 315°, etc. It will be appreciated that fewer or more hinges could be used to join adjacent rings. For example, each ring could be joined to an adjacent ring with two hinges whereby the hinges are adjacent rings are offset by 90°.

In addition, the flexible support60includes a longitudinally extending slot72formed by a gap in each of the rings and extending along the length of the support. The slot72is aligned with the guidewire lumen58within the catheter. As shown inFIG. 3, an outer jacket82may cover the flexible member60. The outer jacket82may be made from or coated with a lubricious material, such as PTFE, to facilitate passage of the catheter within a patient's body.

The outer jacket82preferably includes a slit, perforation, slot or the like positioned over the area of the longitudinally extending slot72in the flexible support60and the guidewire lumen58. In this manner, a guidewire that is positioned within the guidewire lumen58can be pulled through the outer jacket82and the slot72within the flexible support60in order to peel the catheter50off the guidewire.

The flexible support60may be made from a hypotube made from a material such as stainless steel, wherein the rings and hinges are cut with a laser, chemically etched, or ground into the hypotube. Alternatively, the support member60can be molded from plastic or other suitable materials.

As an alternative to making the support member60out of a hypotube, the support member60can be made from a flat sheet of material such as stainless steel and rolled or formed into a final shape. As shown inFIG. 5A, a flexible support90includes a number of band elements92,94,96,98that are joined with hinges100extending generally perpendicular to the length of the bands. In the embodiment shown, the hinges100between adjacent pairs of bands are staggered or offset from each other. The flexible support90can be stamped, molded, etched, or laser cut from a piece of flat material before being rolled or formed into a final shape. Although the bands are shown as being joined together with four hinges in the embodiment shown inFIG. 5A, this is not required.FIG. 5Billustrates an embodiment wherein adjacent bands are joined together with two hinges102. Each pair of hinges102is offset, for example, by 90 degrees, with respect to an adjacent pair of hinges. Once rolled or formed into a tubular shape, each of the bands92,94,96,98become the rings of the flexible support. The opposite edges of the bands can be spaced apart to form the slot that is aligned with the guidewire lumen. Alternatively, the opposite edges can be joined by welding or the like and a new slot cut therein to allow passage of the guidewire.

FIG. 5Cillustrates yet another embodiment of a flexible support120. In this embodiment, the support comprises a cylindrical tube having interlocking elements122,124, etc., that are joined by a pattern of cuts125. The flexible support120resists compression along its length, but transfers rotational torque when incorporated into the catheter. In addition, the flexible support includes a slot130that allows passage of a guidewire out of the guidewire lumen. The flexible support120can be made in a manner similar to that used to make medical stents.

FIG. 6illustrates a catheter50routed over a guidewire140. At the proximal end of the catheter is an opening142that allows access to the guidewire lumen within the catheter. A slot144extends from the opening142towards the distal tip52of the catheter and is positioned over the guidewire lumen. In the embodiment shown, the guidewire140has a distal end that extends through the opening at the distal end of the guidewire lumen and a proximal end that extends out of the opening142in the catheter body. To remove the catheter50from the guidewire140, the guidewire140is pulled through the slot144extending along the length of the catheter. Because the flexible support60has the slot72therein, the guidewire can be pulled through outer jacket82to exchange the catheter.

FIG. 7illustrates one embodiment of an extrusion used to form the various lumens in the catheter. As indicated above, the extrusion150may include a working channel lumen152, a second lumen154that can be used to route an optical fiber or other tools through the device. In addition, one or more additional lumens156may be provided to pass tools, gases, or liquids through the device. In addition, the extrusion150includes a guidewire lumen160. The guidewire lumen160is generally U-shaped such that the lumen has one side open along the circumference of the extrusion150.

In the example shown inFIG. 7, the extrusion150also includes a number of control wire lumens162,164,166,168through which corresponding control wires170,172,174,176can be routed. Each of the control wires170-176has a distal end that is secured at or adjacent the distal end of the catheter and can be selectively tensioned in order to bend the catheter in a desired direction. Although the example shown uses four control wires, it will be appreciated that directional control of the device can be obtained with more or fewer control wires if desired.

In accordance with one embodiment, the flexible support60is positioned over the extrusion150so that the slot72is positioned over the guidewire lumen. The outer jacket82is then placed over the flexible member by, for example, an extrusion process or heat reaction, dipping, etc. The flexible support60, therefore, is sandwiched between the extrusion150and the outer jacket82.

FIGS. 8A-8Cillustrate various embodiments of an entrance to the guidewire lumen through the outer jacket82of the catheter. In the embodiment shown inFIG. 8A, the entrance comprises a perforated slot180extending along the length of the catheter or portion thereof. In the embodiment shown inFIG. 8B, the entrance to the guidewire channel includes a slot182, wherein the edges of the slot remain some distance apart. In the embodiment shown inFIG. 8C, the entrance to the guidewire channel along the length of the catheter comprises a slit184wherein the edges of the slit abut each other. In yet another embodiment, the area over the guidewire channel may be completely sealed by the outer jacket of the catheter. However, the outer jacket may be thin enough in this area such that a guidewire can be pulled through the outer jacket. In yet another embodiment, the outer jacket can be coextruded with a softer material along its length to provide a weaker wall through which a guidewire can be pulled.

FIG. 9illustrates one embodiment of a steerable catheter system including a rapid exchange lumen. The catheter200includes a handle202at a proximal end. The handle202has a pair of controls204,206that selectively tension or release pairs of control cables positioned within the catheter in order to steer the distal tip in the desired direction. Extending distally from the handle202is a flexible catheter208, in accordance with any of the above-described embodiments, that is inserted into the patient. The catheter208includes a rapid exchange lumen210that allows the catheter208to be easily removed from a guidewire (not shown) by pulling the guidewire through the side of the rapid exchange lumen210in order to exchange the catheter for another one over the guidewire.

While the preferred embodiment of the device has been illustrated and described, it will be appreciated that various changes can be made therein. It is, therefore, intended that the scope of the invention be determined from the following claims and equivalents thereof.