Articulation device having increased visibility

Articulation devices, such as comprising pull rings, are provided having improved or increased visibility under conventional visualization techniques, such as fluoroscopy. Such improved visibility is achieved by the presence of at least one insert comprised of a material that is more visible or detectable under imaging techniques than the pull ring. The at least one insert is positionable within a cut-out in the articulation device and fixed into place by a suitable method such as adhesive, soldering, swaging, welding, laser welding, etc. The insert resides within the dimensions of the walls of the pull ring so as to not increase the outer diameter or decrease the inner diameter of the pull ring. This maintains the profile of the overall articulation device. Thus, the one or more inserts can improve the radiopacity of the pull ring, allowing the pull ring to be more visible and more easily identifiable under fluoroscopy than a conventional pull ring without negatively altering other features such as tensile strength or overall dimensions of the pull ring.

BACKGROUND OF THE INVENTION

A variety of devices have an articulating distal end which is controlled by a mechanism disposed along its proximal end. This allows remote articulation of the distal end and is particularly useful for situations wherein the distal end is not accessible. In medical devices, a variety of catheters and surgical instruments have elongate distal ends which are introducible into the body for various treatment procedures. Typically, the proximal end includes a handle which remains outside of the body and includes mechanisms for controlling and articulating the distal end which is remote and inaccessible.

FIG. 1illustrates an example catheter10comprising an elongate shaft12and handle16. Here, the elongate shaft12is articulatable along its distal end14for steering and maneuvering remotely. In this example, such articulation is achieved with the use of a pull ring20positioned around the elongate shaft12near the distal end14which is connected to a pull wire22which extends along the shaft12toward a proximal end18. In this example, the pull wire22is connected to a rotating cuff24along the handle16, wherein rotation of the cuff24applies pulling force to the pull wire22which causes bending of the distal end14as indicated by the dashed line image. In this example, rotation of the cuff24in the opposite direction releases the pulling force and allows the distal end14to recoil to its original position. It may be appreciated that a pull ring20may have multiple pull wires22for articulation in various directions, and/or a catheter10may have multiple pull rings20for various types of articulation.

Typically, pull rings20and their attached pull wires22are comprised of stainless steel due to the large forces applied for articulation. In some instances, a pull ring20with a 0.010 inch pull wire22having an ultimate tensile strength of 27 lbf will have a design requirement of 15-20 lbf. Or, a pull ring20with a 0.015 inch pull wire22having an ultimate tensile strength of 62 lbf may have a design requirement of 40-50 lbf.

Typically, the pull ring20is cut from full-hard stainless steel tubing and includes a slot30which is laser cut into the wall of the tubing for insertion of the pull wire22, as illustrated inFIG. 2. In this example, the pull ring20is cut from tubing having an outer diameter of 0.230 inches and an inner diameter of 0.200 inches, thus having a wall thickness of 0.015 inches. The pull wire22is then welded to the wall of the tubing to fix the pull wire22in place. Such welding is usually low energy so that the pull wire22is not significantly damaged. In this example, the pull wire22has a diameter of 0.015 inches. In most instances, the pull ring20is has a length that is as short as practical to minimize stiffness of the catheter shaft12when placed therearound, allowing the catheter to easily track over a guidewire or pass through an introducer. In this example, the pull ring20has a length of 0.150 inches. In addition, the slot30is typically cut as long as practical to maximize the weld length (allowing the use of low energy) so that the pull wire22does not fail in shear. This combination of design features, particularly low energy welds over a long distance, maximizes the ultimate tensile strength of the weld so as to approach the ultimate tensile strength of the wire.

Since the distal end14of the catheter10is within the patient during use, the user is unable to visualize the articulation of the distal end14. In most situations, such visualization is achieved by the use of fluoroscopy. In some instances, one or more marker bands are positioned along the catheter shaft12wherein the marker bands are comprised of a radiopaque material, such as gold or platinum, which is visible under fluoroscopy. However, such bands add additional cost, labor and dimension to the catheter10. In some instances, pull rings20may be used to assist in visualization of the articulating end, however thin bands of stainless steel are difficult to easily identify under fluoroscopy, particularly amid other devices used in conjunction with the articulating catheter and other hardware that may have been previously installed in the patient.

Consequently, pull rings20have been modified to increase their visibility under fluoroscopy. For example, stainless steel pull rings20have been plated in gold to increase their visibility. Such plating is typically 0.002 or 0.003 inches thick. This significantly increases the wall thickness of the pull ring20, such as adding dimension to the inner diameter and outer diameter of the pull ring20. Thus, the catheter10will have an overall larger French size and a smaller lumen through which to pass another device, both of which are contrary to optimization of the catheter10.

In other instances, platinum marker bands have been positioned adjacent to or on top of stainless steel pull rings20. Placing the marker band adjacent to the pull ring20creates a long region of stiffness along the catheter shaft12, reducing the flexibility of the shaft12. Placing the marker band on top of the pull ring20increases the diameter of the pull ring20, which as mentioned increases the overall French size of the device which is disadvantageous.

In yet other instances, platinum marker bands have been attempted to be used as pull rings20, however platinum is relatively soft even with the addition of elements such as tungsten or iridium. Stainless steel pull wires22welded to platinum marker bands will not produce the desired ultimate tensile strength for most design applications where pull rings20are used for articulation, leading to breakage of the bond and/or damage to the marker band, pull wire, or catheter.

Therefore, improved methods and devices are desired for visualization of remotely articulating portions of devices or instruments without compromising design features such as profile, inner diameter, outer diameter, flexibility or strength. At least some of these objectives are met by the present invention.

SUMMARY OF THE INVENTION

The present invention generally relates to articulation devices, such as comprising pull rings, having improved or increased visibility under conventional visualization techniques, such as fluoroscopy. Such improved visibility is achieved by the presence of at least one insert comprised of a material that is more visible or detectable under imaging techniques than the pull ring. The at least one insert is positionable within a cut-out in the articulation device and fixed into place by a suitable method such as adhesive, soldering, swaging, welding, laser welding, etc. The insert resides within the dimensions of the walls of the pull ring so as to not increase the outer diameter or decrease the inner diameter of the pull ring. This maintains the profile of the overall articulation device. Thus, the one or more inserts can improve the radiopacity of the pull ring, allowing the pull ring to be more visible and more easily identifiable under fluoroscopy than a conventional pull ring without negatively altering other features such as tensile strength or overall dimensions of the pull ring.

In a first aspect of the invention, an articulation device is provided comprising a tubular pull ring having a first end, a second end and a circumferential wall, wherein the wall includes at least one cut-out; at least one radiopaque insert fixedly inserted into the at least one cut-out so that the insert is disposed within the wall without increasing thickness of the wall; and a pull wire fixedly attached to the pull ring, wherein the tubular pull ring is mountable on a distal end of a shaft so that application of force to the pull wire articulates the distal end of the shaft.

In some embodiments, the radiopaque insert comprises a wire. In other embodiments, the radiopaque insert comprises a ribbon or sheet. In yet other embodiments, the radiopaque insert comprises a polymer or ceramic embedded with radiopaque material.

In some embodiments, the radiopaque insert has a higher radiopacity than the pull ring. For example, in some embodiments, the radiopaque insert is comprised of platinum or gold. This may be particularly the case when the pull ring is comprised of stainless steel.

In some embodiments, the cut-out has a rectangular, oval, round, circular, square or spiral shape. In some embodiments, the cut-out has a shape of a letter, word, number, symbol or logo.

In some embodiments, the radiopaque insert is fixedly inserted by adhesive, soldering, swaging, welding, or laser welding the radiopaque insert to the pull ring. In some embodiments, the at least one cut-out is disposed along the wall of the pull ring in an arrangement which provides an indication of rotational orientation of the pull ring around its longitudinal axis when visualized from one side.

In some embodiments, the articulation device further comprises at least one additional pull wire fixedly attached to the pull ring, wherein the at least one cut-out is disposed between fixation points of the pull wire and the at least one additional pull wire to the pull ring.

In a second aspect of the present invention, an articulation device is provided comprising a tubular pull ring having a first end, a second end and a circumferential wall, at least one radiopaque wire or ribbon fixedly attached to an end surface of the first end or second end of the pull ring without increasing thickness of the wall; and a pull wire fixedly attached to the pull ring, wherein the tubular pull ring is mountable on a distal end of a shaft so that application of force to the pull wire articulates the distal end of the shaft.

In some embodiments, the at least one radiopaque wire or ribbon has the shape of a ring. In other embodiments, the at least one radiopaque wire or ribbon has the shape of a coil.

A method of fabricating an articulation device comprising removing a portion of a wall of a tubular pull ring to create a cut-out; inserting a radiopaque insert into the cut-out so as to not increase thickness of the wall, wherein the radiopaque insert has a higher radiopacity than the pull ring; and fixing the radiopaque insert to the pull ring.

In some embodiments, the radiopaque insert comprises a wire, ribbon or sheet. In some embodiments, inserting the radiopaque insert comprises filling the cut-out with a polymer or ceramic embedded with radiopaque material. In some embodiments, the cut-out has a shape of a rectangle, oval, circle, square, spiral, letter, word, number, symbol or logo.

In some embodiments, fixing the radiopaque insert comprises adhering, soldering, swaging, welding, or laser welding the radiopaque insert to the pull ring.

In some embodiments, removing the portion of the wall of the tubular pull ring to create the cut-out comprises removing the portion of the wall to create the cut-out in an arrangement which provides an indication of rotational orientation of the pull ring around its longitudinal axis when visualized from one side.

In some embodiments, removing the portion of the wall of the tubular pull ring to create the cut-out comprises removing a plurality of portions of the wall to create a plurality of cut-outs arranged so as to provide an indication of rotational orientation of the pull ring around its longitudinal axis when visualized from one side.

In some embodiments, the method further comprises fixedly attaching a pull wire to the pull ring.

These and other embodiments are described in further detail in the following description related to the appended drawing figures.

INCORPORATION BY REFERENCE

DETAILED DESCRIPTION OF THE INVENTION

Specific embodiments of the disclosed device and method will now be described with reference to the drawings. Nothing in this detailed description is intended to imply that any particular component, feature, or step is essential to the invention.

FIG. 3illustrates an embodiment of an articulation device100used to articulate a device or instrument, such as a catheter. In this embodiment, the articulation device100is comprised of a pull ring102having a tubular shape, sized and configured to extend around a distal end of an elongate shaft, such as a catheter shaft. In this embodiment, the articulation device100further comprises a pull wire104fixedly attached to the pull ring102. It may be appreciated that the pull wire104has an elongate shape and may be comprised of a wire or ribbon. Typically, the pull ring102includes a notch106extending from one end of the pull ring102along a portion of its length so as to create sufficient surface area for bonding to the pull wire104. The pull wire104is inserted into the notch106and fixed to the pull ring102, such as by laser welding the pull wire104to the edges of the notch106. This creates a secure bond able to provide high ultimate tensile strengths, such as 4-100 lbf. When the pull ring102is mounted on a shaft of a catheter or similar device, applying force to the pull wire104laterally bends the shaft in the direction of the pull wire104for articulation.

In this embodiment, the articulation device100further comprises at least one insert108. Each insert108is insertable into a cut-out110of the pull ring102. The cut-out110is a slot, window, groove or area where material has been removed from the wall of the tubular pull ring102. Thus, the insert108is configured to be insertable into the cut-out110so that the insert is disposed within the wall of the pull ring102without increasing the thickness of the wall. The insert108is comprised of a material that is more visible or detectable under imaging techniques than the pull ring102. For example, in some embodiments, the insert108is comprised of a radiopaque material that has a higher radiopacity than the pull ring102. When the pull ring102is comprised of stainless steel, the insert108is comprised of a material having a higher radiopacity than stainless steel, such as platinum, gold, or any of their common alloys. In some embodiments, the insert108is comprised of a radiopaque wire, ribbon, sheet, or a polymer or ceramic material infused with, embedded with or compounded with radiopaque material. In particular, in some embodiments, the radiopaque insert108is comprised of platinum wire. In other embodiments, the radiopaque insert is comprised of a platinum marker band cut to a desired shape. The cut-out110may have any desired shape, such as rectangular, oval, round, circular, square, spiral, etc. Likewise, the cut-out110may have the shape of letters, words, numbers or symbols.

In any case, once the insert108is inserted into the cut-out110, the insert108is fixed into place by any suitable method such as adhesive, soldering, swaging, welding, laser welding, etc. The insert108is flush with the walls of the pull ring102so as to not increase the outer diameter or decrease the inner diameter of the pull ring102. This maintains the profile of the overall device, such as the French size of the catheter, which is highly desirable in fields where minimal French size is critical. Likewise, this maintains the inner diameter of the overall device, maximizing the area through which instruments and other devices can be passed through an internal lumen. This also does not add length to the pull ring102, maximizing the flexibility of the catheter.

One or more radiopaque inserts108improves the radiopacity of the pull ring102, allowing the pull ring102to be more visible and more easily identifiable under fluoroscopy than a conventional pull ring102without negatively altering other features such as tensile strength or overall dimensions of the pull ring102. In addition, the radiopaque insert108is easily manufacturable. In some embodiments, the insert108is positioned in the cut-out110and fixed in place at the same time that the pull wire104is positioned in the notch106and fixed in place. This provides a simplified assembly process when assembling a catheter or instrument having the articulation device100wherein the articulation device100is attached to the catheter or instrument without the need for additional steps such as adding marker bands. In addition, with minimal inventory of insert material, such as wire, any size pull ring102can be enhanced for visualization. Such assembly techniques are less expensive than other techniques, such as gold plating, and allow more control over a desired visualization pattern, such as a higher concentration of radiopaque material in a particular area.

FIG. 3illustrates an embodiment of an articulation device100having three radiopaque inserts108, each insert108disposed in a rectangular cut-out110extending lengthwise along a portion of the length of the pull ring102, parallel to the notch106. In this embodiment, the inserts108are arranged around the circumference of the pull ring102, such as equally spaced apart. It may be appreciated that a pull ring102may have more than one pull wire104so as to articulate the device in various directions.FIG. 4illustrates an embodiment of an articulation device100having three inserts108and three pull wires104, wherein each insert108is disposed between a pull wire104.

It may be appreciated that an articulation device100may include a variety of different types, shapes, and arrangements of inserts108and cut-outs110. For example,FIG. 5illustrates an embodiment of an articulation device100having an insert108disposed within an arc shaped cut-out110in the wall of the pull ring102. In this embodiment, the cut-out110has a rectangular or strip shape extending perpendicularly away from the notch106, at least partially around the circumference of the tubular pull ring102and ending on the other side of the notch106. Thus, the insert108is visible under fluoroscopy for nearly 360 degrees of rotation of the pull ring102without interfering with the bond of the pull wire104.

Similarly,FIG. 6illustrates another embodiment of an articulation device100having an insert108disposed within an arc shaped cut-out110in the wall of the pull ring102. In this embodiment, the cut-out110has a rectangular or strip shape extending around the circumference of the tubular pull ring102above the notch106. However, the cut-out110is not continuous and a sufficient portion of the wall of the pull ring102remains between the ends of the cut-out110to maintain integrity and strength of the pull ring102. Again, the insert108is visible under fluoroscopy for nearly 360 degrees of rotation of the pull ring102without interfering with the bond of the pull wire104.

FIG. 7illustrates another embodiment of an articulation device100having an insert108disposed within an arc shaped cut-out110in the wall of the pull ring102. In this embodiment, the cut-out110has a spiral shape wherein the cut-out110extends completely around the circumference of the tubular pull ring102in a spiral configuration. Again, a sufficient portion of the wall of the pull ring102remains to maintain integrity and strength of the pull ring102. And, the insert108is visible under fluoroscopy or other imaging techniques for 360 degrees of rotation of the pull ring102without interfering with the bond of the pull wire104.

FIG. 8illustrates an embodiment of an articulation device100having insert108disposed within a geometrically shaped cut-out110in the wall of the pull ring102. In this embodiment, the cut-out110has a square shape. Thus, the corresponding insert108has a square shape and may be comprised of a sheet or other flat material cut to fit the square shape. For example, the insert108may be cut from a conventional marker band and fixed within the cut-out110. In this embodiment, the square shaped cut-out110is disposed on one side of the pull ring102. Therefore, visualization of the square shaped cut-out under fluoroscopy or other imaging techniques indicates the rotational orientation of the pull ring102in addition to the transitional location of the pull ring102within the anatomy. It may be appreciated that the cut-out110may have other geometric shapes, such as triangular, round, oval, etc. It may also be appreciated that the cut-out110may have the shape of a letter, word, number or symbol. For example,FIG. 9illustrates an embodiment wherein the cut-out110has the shape of the letter F. Some shapes, such as the letter F, can indicate rotational orientation of the pull ring102along its longitudinal axis105while also indicating translational and rotational orientation within a plane of the anatomy. For example, when the embodiment ofFIG. 9is visualized wherein the letter F is in an upside-down arrangement, it is known that the pull ring102(and therefore distal end of the catheter) is pointed downward in an x-y plane of the anatomy. Likewise, the amount of the letter F that is visible indicates the rotational orientation of the pull ring102around its own longitudinal axis105. It may also be appreciated that the cut-out110may have the shape of a word or logo.

It may be appreciated that a pull ring102may have a variety of different shaped cut-outs110and inserts108. For example, in some embodiments the pull ring102has cut-outs of various shapes extending around the circumference of the pull ring102, such as a square, circle and triangle. Thus, the shapes provide indication of rotational orientation of the pull ring102around its own longitudinal axis105under visualization.

In some embodiments, the type of insert108indicates rotational orientation of the pull ring102under fluoroscopic imaging. For example, in some embodiments the pull ring102includes a plurality of cut-outs110wherein each cut-out110has an insert108of differing material or differing radiopacity. Thus, inserts108having increasing radiopacity may be disposed circumferentially around the pull ring102. Thus, the rotational orientation of the pull ring102around its longitudinal axis105may be determined under fluoroscopy based on the degree of radiopacity of the insert108that is visible.

FIG. 10illustrates an embodiment of a pull ring102having circular cut-outs110disposed around its circumference. In this embodiment, the cut-outs110are filled with inserts108comprising a polymer or ceramic containing a radiopaque material. In some embodiments, the quantity of radiopaque material varies so as to create inserts108of varying radiopacities. As mentioned above, inserts108having increasing radiopacity may be disposed circumferentially around the pull ring102. Thus, the rotational orientation of the pull ring102may be determined under fluoroscopy based on the degree of radiopacity of the insert108that is visible.

FIGS. 11A-11Billustrate an embodiment wherein the pull ring102includes a plurality of inserts108disposed adjacent to each other along the circumference of the pull ring102. In this embodiment, three inserts108are present.FIG. 11Billustrates a cross-section of the pull ring102ofFIG. 11Aacross segment B-B. Thus, three inserts108are shown disposed within the wall of the tubular pull ring102. In such embodiments, rotational orientation of the pull ring102around its longitudinal axis105under fluoroscopic imaging is indicated by the number of inserts108that are visible.

In some embodiments, the insert108is disposed along an end of the pull ring102. For example,FIG. 12illustrates an embodiment wherein the insert108is fixedly attached to an end of the pull ring108so that the insert108covers the circular cross-sectional edge of the tubular walls of the pull ring108. When the insert108comprises a wire, the wire forms a ring which is fixedly attached to the end of the pull ring108. It may be appreciated that in some embodiments, the insert108extends around a portion of the end surface of the pull ring108, such as in an arc shape. Likewise, more than one insert108may be fixed to the end surface of the pull ring108, such as leaving gaps between them. Further, one or more inserts108may be fixedly attached in a stacked configuration. Still further, the insert108may have the shape of a spring wherein one end of the spring-shaped insert108is fixedly attached to the pull ring108while the other end remains free, as illustrated inFIG. 13.

It may be appreciated that any number and combination of types of cut-outs110may be formed in a pull-ring102. Likewise, any number and combination of types of inserts108may be applied to a pull-ring102. Further, a pull ring102may include both at least one cut-out110having an insert108and at least one insert108fixedly attached to an end surface of the pull ring102. In some embodiments, the pull ring102having at least one insert108is utilized without a pull wire104, to aid in visualization.

It may be appreciated that the pull rings102may have any suitable size or shape for a given application. Pull rings102typically have inner diameters that range in size from 0.014 inches to 0.500 inches and wall thicknesses that typically range in size from 0.0015 inches to 0.020 inches. It may be appreciated that larger pull rings102typically require larger wall thicknesses to maintain structural integrity. Pull wires104are typically wires or ribbons having a thickness of 0.002 inches to 0.020 inches. When ribbons are used, the thickness may be as low as 0.001 inches. In any case, the pull wires104are typically welded to the outside of the pull ring102, inside of the pull ring102or into a notch106cut into the end of the pull ring102. Thus, conventional or specialty pull rings102and pull wires104may be utilized wherein the pull rings102are modified to incorporate inserts108according to the present invention. Such modifications provide improved visualization of remotely articulating portions of devices or instruments without compromising design features such as profile, inner diameter, outer diameter, flexibility or strength.