Patent Application
20240252791
The disclosure relates generally to devices and methods for steerable medical devices. More specifically, aspects of the disclosure pertain to devices and/or methods for steerable guidewires.
Medical procedures that involve navigating to a site within the body often require a medical guidewire. Guidewires are used in numerous catheterization procedures and other medical procedures as an aid to placement of a catheter or other device at a selected site within the human body. Navigation of a guidewire often requires movement and/or steering of the guidewire through complex, tortuous anatomies to arrive at a target anatomy. A guidewire may include a steerable distal portion or tip that may be steered/articulated by a user via a controller. In order to impart such steerable behavior, the distal portion of said guidewire may be cut in various patterns to control its rigidity. This cutting process may require the use of diamond saws or lasers, which can be time-consuming and/or expensive.
This disclosure relates to, among other things, devices and methods for steerable medical devices. Each of the examples disclosed herein may include one or more of the features described in connection with any of the other disclosed examples.
According to one aspect, a medical device may comprise a handle including a handle body, and an actuator; and a shaft extending distally from the handle body. The shaft may comprise a shape memory material. The shaft may include a proximal section and a distal section The proximal section may include a first austenitic finish temperature and the distal section having a second austenitic finish temperature. The first austenitic finish temperature may be lower than the second austenitic finish temperature.
In another aspect, the shaft may further include a transition section between the proximal section and the distal section. The transition section may include a proximal portion having an austenitic finish temperature approximate to or greater than the first austenitic finish temperature. The transition section may further include a distal portion having an austenitic finish temperature approximate to or less than second austenitic finish temperature.
In another aspect, the first austenitic finish temperature may be less than or equal to body temperature, and the second austenitic finish temperature may be greater than body temperature.
In another aspect, the distal section may include at least one indentation. The at least one indentation may be a concave cut, and the at least one indentation may span at least a portion of the circumference of the distal section. The at least one indentation may span a whole circumference of the distal section. The distal section may include a bendable portion. The bendable portion may be of a lesser circumference than a circumference of the remaining portion of the distal section, and the bendable portion may be a portion of the distal section having the thinnest profile.
In another aspect, the distal section may include a plurality of indentations. The distal section may include a first indentation and a second indentation. The first indentation and the second indentation may be of different shapes, and a bending profile of the first indentation may be different from a bending profile of the second indentation. The first indentation may be a concave cut and the second indentation may be a V-shaped cut. Each of the first indentation and the second indentation may span a circumference of the distal section between approximately 20° and approximately 170°. The at least one indentation may be laser cut.
In another aspect, the medical device may further comprise a plurality of steering elements, and each of the plurality of steering elements may extend between the actuator and the distal section through an internal portion of the shaft
In another aspect, both the first austenitic finish temperature and the second austenitic finish temperature may be set via heat treatment of the proximal section and the distal section of the shaft.
According to another aspect, a medical device may comprise a shaft extending distally from the handle body. The shaft may include a shape memory material. The shaft may include a proximal section and a distal section. The proximal section may include a first austenitic finish temperature and the distal section having a second austenitic finish temperature, wherein the first austenitic finish temperature is lower than the second austenitic finish temperature, and wherein the distal section includes a first indentation defining a first bending profile and a second indentation defining a second bending profile, wherein the first bending profile is different from the second bending profile. The first bending profile may be a gradual, U-shaped bend, and the second bending profile may be an abrupt, V-shaped bend. Each of the first indentation and the second indentation may span a circumference of the distal section between approximately 20° and approximately 170°. The first austenitic finish temperature may be less than or equal to body temperature, and the second austenitic finish temperature may be greater than body temperature.
According to another aspect, a method of using a medical device, the medical device may include a handle and a shaft, wherein the handle may include an actuator, wherein the shaft may include a distal section, wherein the distal section may include a first indentation and a second indentation, and wherein the actuator may be coupled to the distal section via at least one steering element, may include delivering the shaft into a bodily lumen; positioning a distal section of the shaft adjacent to a target site; actuating the actuator so the distal section may bend about the first indentation in a first bending profile; and actuating the actuator so the distal section may bend about the second indentation in a second bending profile, wherein the first bending profile may be different from the second bending profile.
It may be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed. As used herein, the terms “comprises,” “comprising,” “having,” “including,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. The term “exemplary” is used in the sense of “example,” rather than “ideal.” The term “approximately,” or like terms (e.g., “substantially”), includes values+/−10% of a stated value.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various exemplary embodiments and together with the description, serve to explain the principles of the disclosure.
Embodiments of this disclosure seek to provide a medical device including a steerable shaft, e.g., a guidewire. The guidewires of this disclosure may be more easily manufactured at a lesser cost relative to existing guidewires including a plurality of cuts staggered along a length of the guidewire, for example, in a diamond cut pattern. The guidewires of this disclosure may comprise a shape memory material, e.g., Nitinol, which has been subjected to a heat treatment or heat cycle process. The application of heat to said shape memory material may impart various characteristics, e.g., superelasticity and/or malleability, to heated aspects of the guidewire, thereby providing variable stiffness throughout a length of the guidewire.
A shape memory material may transition between at least two states, a martensitic state and an austenitic state. Specifically, the material transitions from an austenitic state to a martensitic state with a decrease in temperature to which the material is exposed, and similarly transitions from the martensitic state to the austenitic state with an increase in temperature to which the material is exposed. The temperature at which the transition from the austenitic state to the martensitic state begins is typically designated Ms (martensitic start temperature), while the temperature at which the transition finishes is typically designated Mf (martensitic finish temperature). As the material transitions from the austenitic state to the martensitic state, the material becomes more easily deformable. In the martensitic state, the material is able to accommodate significant deformation at low stress levels. The material exhibits malleable behavior. Due to such malleability, the material may be less likely to break as the material flexes and deforms when forces are applied to it. Thus, the material may accommodate a significant amount of deformation before reaching a breaking point.
Upon heating the material in the martensitic state, the material begins to transition to an austenitic state. The temperature at which this transition begins to occur is designated As (austenitic start temperature). The transition is complete at a temperature designated Af (austenitic finish temperature). The material may continue to accommodate deformation and exhibit malleable behavior before reaching Af. However, once the material is heated to Af, the mechanical characteristics of the material changes, and the material exhibits superelasticity, which may be defined as the ability of the shape memory material to recover from deformation. Thus, a shape memory material heated to Af may exhibit a higher degree of stiffness, pushability, and column strength relative to a shape memory material at temperatures below Af.
The Af of a shape memory material may be altered and/or set to a specific temperature by a heat treatment or heat cycling process. Thus, in some examples, a guidewire comprising a shape memory material may be heat treated, so that a particular Af (e.g., body temperature, temperatures above body temperature, etc.) may be set for the guidewire. In some other examples, various portions of the guidewire may be subjected to different heat treatments, so that each of the various portions have different Afs, resulting in variable stiffness throughout a length of the guidewire. Said heat treatment or heat cycling process for setting Af is not particularly limited, and may be any suitable heat treatment or heat cycling process known in the art.
Although the disclosure may reference guidewires used in conjunction with endoscopic, colonoscopic, and/or ERCP procedures, it will be appreciated that the guidewires may also be utilized for other types of procedures, including intracardiac, coronary vascular, central circulatory system, peripheral vascular, and neurovascular or urologic procedures. The medical devices disclosed herein may have a handle coupled to a proximal end of a shaft, e.g., a guidewire. The shaft may have at least two degrees of freedom for movement. The shaft may be articulated (e.g., bent or deflected) in one or more directions. Furthermore, the shaft may be rotatable and movable proximally and distally. The handle may be removable from the shaft, which may facilitate use of the guidewire to guide tools or medical devices after the guidewire is positioned. The shaft may include a lumen with one or two articulation wires, either or both of which may be utilized to achieve a desired steering/articulation of the shaft. The medical devices disclosed herein may be used in conjunction with duoendoscopes, endoscopes, colonoscopes, ureteroscopes, gastroscopes, bronchoscopes, laparoscopes, sheaths, catheters, or any other suitable delivery device. Moreover, the disclosed medical devices may be compatible with robotics platforms.
Reference will now be made in detail to examples of the disclosure described above and illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.
The terms “proximal” and “distal” are used herein to refer to the relative positions of the components of an exemplary medical device. When used herein, “proximal” refers to a position relatively closer to an operator using the medical device. In contrast, “distal” refers to a position relatively farther away from the operator using the medical device.
Actuator 26 may be any suitable actuator (e.g., spool, slider, knob, etc.) that is coupled to and/or movable relative to a portion of body 24. Actuator 26 may be actuated via any suitable means. For example, actuator 26 may be rotatable in a clockwise or counter-clockwise direction relative to body 24. In another example, actuator 26 may slidably translate along body 24 in a proximal and/or distal direction. Actuator 26 may be coupled to one or more steering element(s) 56 (shown in
Actuator 26 may be coupled to proximal ends of steering element(s) 56, for example, via a friction fit, an adhesive, a press fit, a crimping, or any other appropriate coupling mechanism. In this aspect, movement of actuator 26 relative to body 24 may control the pulling of one or more steering elements 56, and thus control the steering of a distal portion 34 of shaft 14. The number of steering elements 56 is not particularly limited (e.g., one or more steering elements 56), and the number of steering elements 56 may correlate with the number of different directions that shaft 14 may articulate. Moreover, although not shown, handle 12 may further include one or more springs or biasing elements, for example, within the internal lumen of body 24, to bias the movement actuator 26. For example, the one or more springs or biasing elements may bias actuator 26 to a default position in which no forces are applied to any one of steering elements 56, thereby maintaining distal portion 34 in a neutral, non-bent configuration. Additionally or alternatively, one or more portions of handle 12 may include a locking mechanism, for example, to selectively and/or releasably secure a position of actuator 26.
Collet 28 may be positioned at a distal end of body 24. As shown in
Shaft 14 may be a wire or tube-like structure (e.g., a guidewire) including an annular body 144 defining a lumen 142 (shown in
Shaft 14 may include a proximal section 32, a transition section 33, and a distal section 34, as shown in
Each of sections 32, 33, 34 of shaft 14 may comprise Nitinol and/or any other shape memory material. Moreover, as discussed above, proximal section 32 and distal section 34 may each undergo a different heat treatment or heat cycling process so that a different Af is set for each of sections 32, 34. For example, proximal section 32 may undergo a first heat treatment so that the Af of proximal section 32 is set to a first temperature (e.g., body temperature (approximately 36.2° C. to approximately 37.2° C.) or a temperature below body temperature). Distal section 34 may also undergo a second heat treatment so that the Af of distal section 34 is set to a second temperature (e.g., a temperature above body temperature). The order of the first heat treatment and the second heat treatment are not particularly limited.
As a result of the different heat treatments, proximal section 32 and distal section 34 may exhibit different mechanical characteristics when both proximal section 32 and distal section 34 are heated to a first temperature or to a second temperature, but not the other. For example, when said first temperature (e.g., Af of proximal section 32) is body temperature or a temperature below body temperature, proximal section 32 may exhibit superelasticity when inserted into a body and exposed to body temperature. Such superelasticity may help to provide proximal section 32 with improved pushability and column strength so that shaft 14 may be manipulated and/or advanced through tortuous anatomies with a reduced likelihood of buckling or deformation to proximal section 32. When said second temperature (Af of distal section 34) is a temperature above body temperature, distal section 34 maintains its malleable characteristics while inserted into the body and exposed to body temperature. Thus, distal section 34 of shaft 14 may be steerable via steering elements 56 and actuator 26.
As shown in
Distal section 34 may additionally include a cut or indentation (e.g., a laser cut), which may help to further improve the steerability of distal section 34. For example, as shown in
Heat treatment of distal section 34 including indentation 342 may help to provide improved articulation thereof (e.g., an increased degree of articulation from one side of section 34 to the other), as well as improved stress concentration preventing breakage. Such a process of heat treating distal section 34 may be more cost-effective than conventional articulation sections, which require a plurality of steering wires and corresponding lumens. Furthermore, the stiffness of the material at the flexible distal section of conventional articulation sections is the same as that of the bulk material proximal to said flexible section. The flexibility in such devices is created through a series of small mechanical linked/interlocked mechanical elements, or through a laser cut pattern that enables the laser cut portion to bend in multiple directions. In contrast, as discussed above, distal section 34 may be subjected to selective heat treatment(s) to create malleability in the shape memory material itself. Moreover, in some embodiments, additional mechanical flexibility, as well as bending properties/biases, may be imparted by the thinning of distal section 34 thereby defining indentations, e.g., indentation 342.
Also referring to
First indentation 342′ may be a concave, semi-circular cut (i.e., extending radially inwards) around a partial circumference of distal section 34. The shape and dimensions of first indentation 342′ are not particularly limited. The degree by which first indentation 342′ extends around or spans a circumference of distal section 34′ is also not particularly limited, and may, for example, range between approximately 20° and approximately 170°. First indentation 342′ yields a first bending profile of distal section 34′. Given the semi-circular cut of first indentation 342′, the first bending profile may be a gradual, U-shaped bend around a central point 342′a, and may also be referred to as a ‘sugar-cane’ bending profile. Such a bending profile may define a gradual curvature around central point 342′a, and the bending profile may be similar in shape to that of a sugar cane, candy cane, and other similar shapes. The degree of bend around point 342′a that may be possible is dependent on the shape and dimensions of first indentation 342′.
Second indentation 344′ may be a V-shaped cut (i.e., extending radially inwards) around a partial circumference of distal section 34, for example, around a portion of the circumference of distal section 34 that is unencumbered by first indentation 342′. The shape and dimensions of second indentation 344′ are also not particularly limited. The degree by which second indentation 344′ extends around or spans a circumference of distal section 34′ is also not particularly limited, and may, for example, range between approximately 20° and approximately 170°. In some examples, second indentation 344′ may extend around distal section 34′ by the same degree in which first indentation 342′ extends around distal section 34′. However, the degree by which second indentation 344′ extends around distal section 34′ may also differ from that of first indentation 342′. Second indentation 344′ yields a second bending profile of distal section 34′. Given the V-shaped cut of second indentation 344′, the second bending profile of distal section 34′ may bend about low point 344′a, and may also be referred to as a ‘hockey stick’ bending profile. Second indentation 344′ may include a proximal portion 344′p and a distal portion 344′d on both sides of low point 344′a. As shown in
Medical device 10′ may be used in the same or similar manner as discussed above for medical device 10. Additionally, referring to
It is contemplated that the guidewires and methods discussed herein may be applicable to any endoscopic and/or minimally invasive procedure. For example, the systems, devices, and methods discussed above may be used during a percutaneous nephrolithotomy/nephrolithotripsy (PCNL), endoscopic retrograde cholangiopancreatography (ERCP), balloon and laser angioplasty, nephrostomy, electrode placement, etc. The systems, devices, and methods discussed above may also be used in procedures to remove ureteral stones, gallstones, bile duct stones, polyps, stent placement, gastroenteral anastomosis, choledochoduodenostomy, etc. The systems, devices, and methods discussed above may also be used in intracardiac, coronary vascular, central circulatory system, peripheral vascular, and neurovascular procedures.
While principles of the disclosure are described herein with reference to illustrative examples for particular applications, it should be understood that the disclosure is not limited thereto. Those having ordinary skill in the art and access to the teachings provided herein will recognize additional modifications, applications, embodiments, and substitution of equivalents all fall within the scope of the features described herein. Accordingly, the claimed features are not to be considered as limited by the foregoing description.
This application claims priority to U.S. Provisional Application No. 63/481,615, filed on Jan. 26, 2023, which is incorporated by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63481615 | Jan 2023 | US |
