Systems and methods for multi-degree-of-freedom bend and bend length control in coaxially aligned robotically steerable guidewires

Abstract

Guidewire control system and method: A coaxially aligned, tendon-driven, steerable guidewire robot that can simultaneously and independently control the bend angle and length of a bend segment, thereby performing a "follow the leader" motion at its distal bend segment.

Description

[Technical Field]

[0001] (CROSS-REFERENCE TO RELATED APPLICATIONS) This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Patent Application No. 63 / 013,425, filed April 21, 2020, which is incorporated herein by reference as if set forth in its entirety.

[0002] (Statement Regarding Federally Sponsored Research or Development) This invention was made with U.S. government support under Grant No. R01HL144714 awarded by the National Institutes of Health. The U.S. government has certain rights in this invention.

[0003] (Names of parties to the joint research agreement) Not applicable

[0004] (Sequence Listing) Not applicable

[0005] (Statement regarding prior disclosure by inventor or co-inventors) Not applicable

[0006] (Technical field to which the invention belongs) The present disclosure relates generally to systems and methods for guidewire control, and more particularly to systems and methods for multi-degree-of-freedom bend and bend length control in coaxially aligned, robotically steerable guidewires. [Background technology]

[0007] Cardiovascular disease (CVD), including chronic heart disease, stroke, and hypertension, is one of the top 10 causes of death in the United States, accounting for approximately $330 billion in direct and indirect costs in 2014. Most minimally invasive CVD treatments begin with a clinician inserting a guidewire into the patient's vascular system at an appropriate location and guiding it into the blocked (or diseased) blood vessel. Most procedures for treating peripheral arterial disease (PAD) require surgeons to use various catheters that ride over the guidewire. These catheters may contain tools for performing atherectomy, such as microdrills, or drug delivery units (in the form of drug-coated balloons) to help prevent further deposition in the arteries.

[0008] Guidewires are passive wires, typically made of nitinol, with diameters ranging from 0.3556 mm to 0.889 mm (typical wires range from 0.3556 mm to 0.4572 mm, or commonly referred to as 0.014 inch to 0.018 inch guidewires), and lengths ranging from 50 cm to 260 cm, depending on the interventional route. Once the guidewire is guided into the occluded vasculature, clinicians can use the wire as a carrier for various catheters to help clear the blockage.

[0009] The physician manually manipulates the guidewire into the target artery by proximal insertion, retraction, and rotation of the wire base—the only degrees of freedom (DoF) available to the clinician for control of the distal tip—while observing its movement on real-time fluoroscopic images. Such dexterous guidance of the guidewire tip under two-dimensional visual feedback is difficult, time-consuming, and requires considerable experience. Furthermore, angulation, vessel tortuosity, or vessel calcification can make guidewire control difficult, potentially leading to kinking and breakage of the guidewire.

[0010] Although it is possible to change the wires for alternative guidewires with different stiffness / curvature, multiple sets of guidewires are required, and repeated guidewire exchanges can cause vascular trauma. These difficulties in manual navigation also lead to increased procedure time and radiation exposure for the patient, clinician, and operating room staff.

[0011] Conventional steerable guidewires and microcatheters have limitations. Due to wire diameter size constraints, the majority of wires are manually actuated, automatically / robotically actuated externally using, for example, a magnetic source, or tendon-driven. The setup required for magnetic actuation is bulky and can interfere with imaging modalities such as fluoroscopy and magnetic resonance imaging (MRI). In tendon-driven designs, the guidewire has a fixed joint length and does not provide any kind of "leader-following" behavior, making it difficult for the guidewire to navigate tortuous anatomical pathways.

[0012] To achieve leader-following motion, conventional tendon-driven continuum robots have extensible flexures, but the limited range of extensible length makes it difficult to achieve ideal leader-following motion, and its size / complexity makes it impractical for guidewire applications.

[0013] Conventional mechanisms such as concentric tube assemblies allow the robot's curvature and bend angle to change with increasing joint length, but are complex to model and involve instabilities caused by the existence of multiple minimum energy states that result in the robot "snapping" from one minimum energy state to another during operation, potentially resulting in accidental trauma to the patient.

[0014] One innovative way to circumvent these problems is to introduce notch structures in each of the tubular elements.

[0015] However, in all previous designs, the combination of joint length and bend angle of the system is maintained, i.e., the bend length and bend angle of these systems cannot be controlled individually.

[0016] Therefore, innovation is needed to provide a guidewire control system and method that overcomes the limitations of conventional systems and methods. Accordingly, one focus of the present invention is to provide a coaxially aligned, tendon-driven, steerable guidewire robot that can simultaneously and independently control the bend angle and length of a bend segment, thereby performing a "leader-following" motion at its distal bend segment. Summary of the Invention

[0017] Briefly, in accordance with exemplary embodiments of the present invention, an innovative coaxially aligned steerable guidewire system and method is provided that is sized for the vasculature and provides variable curvature at its distal end and independently controlled bend length. In some exemplary embodiments, the present invention operates manually, while in other embodiments, it operates under automatic / robotic control.

[0018] In an exemplary embodiment of the present invention, the robotic system includes three coaxially aligned hollow bodies or tubes with a single tendon running through the center along the length of the robot. The tendon comprises a superelastic wire. A superelastic material may include any material capable of reversibly deforming up to approximately 10% strain. For example, in some embodiments, various components of the present invention may be made of nitinol. However, it should be understood that various components of the present invention may be made of any material, and when used in a biological environment, the material may include biocompatible materials that are not necessarily superelastic, including, but not limited to, biocompatible metals, biocompatible alloys, biocompatible plastics, or materials with biocompatible coatings. Other biocompatible materials include, but are not limited to, titanium or stainless steel. In an exemplary embodiment, the outer tubular element is made of micromachined nitinol, which allows tendon-driven bending in various segments of the robot, thereby allowing for variable bending curvature, and the inner stainless steel tube controls the bending length of the robot. By inserting and retracting the entire assembly, various joint lengths and curvatures can be achieved by changing the relative positions of the tube and tendon, allowing for a tracking leader motion, and a controller controls the distal tip of the robot.

[0019] The entire robotic assembly can be miniaturized to a range of overall outer diameters suitable for use as a microscale, steerable robotic guidewire. The guidewire can be advanced with its distal end through complex vasculature of varying curvatures with minimal interaction and support from the vessel wall. The present invention allows for vascular interventional procedures to be performed using a guidewire guidance system, thus avoiding the need for an alternative guidewire, thereby significantly reducing surgical time and labor. In some embodiments, for example, when a guidewire is used through an artery, the tip of the guidewire can have a width of about 0.1 mm to about 0.9 mm. In some embodiments, the width of the tip of the guidewire can be about 0.3, about 0.33 mm, about 0.35 mm, about 0.4 mm, about 0.45 mm, about 0.50 mm, about 0.55 mm, about 0.60 mm, about 0.65 mm, about 0.7 mm, about 0.75 mm, about 0.78 mm, about 0.8 mm, about 0.85 mm, about 0.88, about 0.89 mm, or about 0.9 mm. In some embodiments, the width of the guidewire may be about 0.31 mm to about 0.34 mm, about 0.36 mm to about 0.39 mm, about 0.41 mm to about 0.44 mm, about 0.46 mm to about 0.49 mm, about 0.51 mm to about 0.54 mm, about 0.56 mm to about 0.59 mm, about 0.61 mm to about 0.64 mm, about 0.66 mm to about 0.69 mm, about 0.71 mm to about 0.74 mm, about 0.76 mm to about 0.79 mm, about 0.81 mm to about 0.84 mm, or about 0.86 mm to about 0.89 mm. In certain embodiments, the tip of the guidewire may have a width greater than about 1.0 mm. For example, in pediatric neurosurgery, an endoscopic tool having a width of about 2.0 mm may be used.

[0020] In another exemplary embodiment of the present invention, a robotically steerable guidewire system includes a path-providing guide comprising a plurality of coaxially aligned tubular elements and a tendon connected to one of the plurality of tubular elements, the path-providing guide having a proximal portion and a distal portion and configured to position a distal end of the guidewire at a target location; and a controller operatively connected to the path-providing guide and configured to control one or more of: controlling relative axial alignment, relative lateral alignment, and relative rotational alignment of the plurality of tubular elements; and controlling a stroke of the tendon, wherein the path-providing guide and controller are configured to cooperate to simultaneously and independently control the curvature of the distal portion of the path-providing guide and to control the arc-length of the distal portion of the path-providing guide.

[0021] One inventive feature of the present invention is the adjustable stiffness / compliance along the length of the pathway-providing guide, generally becoming less stiff from its proximal end to its distal end, providing innovative control over both curvature and bending length at the distal end. This can be implemented in a number of ways. Various segments in the pathway-providing guide can have relatively uniform stiffness along their length, with stiffness adjustable in discrete "steps" throughout the length of the pathway-providing guide. Stiffness can also be controlled by various types of stiffness features on / in one or more tubular elements. For example, the wall thickness of a tubular element can be varied along its length, thereby providing a varying stiffness profile along the length of the segment, and thus the length of the pathway-providing guide. The stiffness profile can be varied by various other mechanisms, such as changing the cross-sectional profile, changing the material composition of the segment, or including separate portions of the pathway-providing guide / segment with a first material (a mixture of materials) having a first stiffness and a second material (a mixture of materials) having a second stiffness. In another exemplary embodiment, the stiffness features may include notches / pairs of notches along a portion of the length of the tubular element, and the pairs of notches may have the same length or different lengths.

[0022] The coaxially aligned tubular elements may include an inner tubular element having an inner channel, an intermediate tubular element having a rigid feature with a set of notches along at least a portion of its length, and an outer tubular element having a rigid feature with a set of notches along at least a portion of its length, each of the plurality of tubular elements having suitable cross-sectional dimensions such that the guide wire is rotationally and laterally displaceable within the inner channel of the inner tubular element, the inner tubular element is rotationally and laterally displaceable within the intermediate tubular element, and the intermediate tubular element is rotationally and laterally displaceable within the outer tubular element.

[0023] The interaction of both sets of notches helps to vary the stiffness of the pathway-providing guide along its length, generally becoming less stiff from the proximal end to the distal end, providing innovative control over both curvature and bend length at the distal end. Both sets of notches can have the same length or different lengths. The intermediate tubular element can have a length defined from the proximal end to the distal end, with the set of notches beginning at a midpoint of the intermediate tubular element and extending to the distal end.

[0024] The outer tubular element can have a length defined from a proximal end to a distal end, with the set of notches beginning at an intermediate location on the outer tubular element and extending to the distal end.

[0025] The length of the set of notches on the outer tubular element may be the same as or different from the length of the set of notches on the intermediate tubular element, for example, in an exemplary embodiment, the length of the set of notches on the outer tubular element is longer than the length of the set of notches on the intermediate tubular element.

[0026] The set of notches on the outer tubular element can have the same phase as the set of notches on the intermediate tubular element, or can have a phase difference that can facilitate operational independence of the intermediate tubular element from the outer tubular element, e.g., allowing the intermediate tubular element to be operatively rotatable and laterally displaceable within the outer tubular element.

[0027] For example, both sets of notches may be offset from one another by 5°, 10°, 15°, 20°, 35°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, 90°, 95°, 100°, 105°, 110°, 115°, 120°, 125°, 130°, 135°, 140°, 145°, 150°, 155°, 160°, 165°, 170°, 175°, or 180°. In some embodiments, both sets of notches may be offset from one another by 1°-5°, 6°-10°, 11°-15°, 16°-20°, 21°-25°, 26°-30°, 30°-45°, 45°-60°, 60°-75°, 75°-90°, 90°-100°, 100°-120°, 120°-135°, 135°-150°, 150°-160°, 160°-175°, or 175°-180°. The phase of each set of notches may also be varied.

[0028] An individual notch can be any geometric shape. In an exemplary embodiment, the recess can be rectangular. In other embodiments, the recess can be, for example, sinusoidal or triangular. In some embodiments, multiple recesses can be different shapes. In other embodiments, sets of notches can have different shapes within each set (one set has one shape and another set has a different shape), while the shapes of the notches within a single set can be different. For example, a single set of notches can have some rectangular notches, some sinusoidal notches, and some triangular notches, and / or the pitch of the notches in a single set can vary along its length. Essentially, the shape of the notches can vary along the length of the element. In one embodiment, the shape of the recess can be selected from the group consisting of rectangular, sinusoidal, semicircular, or triangular.

[0029] Both sets of notches can form unidirectional, asymmetric notch junctions in the intermediate and outer tubular elements. Asymmetric notches can be described as notches that allow the neutral bending plane of the device to be offset toward the outer edge of the device, as opposed to below the central axis of the device as is typically the case with symmetric notches. The asymmetric pattern of notches allows the guidewire tip to bend with a longer moment arm in one direction within the plane of the notch cuts, thus allowing for a wider range of motion.

[0030] The distal end of the guidewire can be defined by a width and a length. Each notch can be defined by a depth. In some embodiments, the depth of each notch can be greater than 50% of the width of the distal end of the guidewire. In some embodiments, the depth of each notch can be about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, or about 95% of the width of the distal end of the guidewire. In some embodiments, the depth of each notch can be about 51% to about 54%, about 56% to about 59%, about 61% to about 64%, about 66% to about 69%, about 71% to about 74%, about 76% to about 79%, about 81% to about 84%, about 86% to about 89%, or about 91% to about 94% of the width of the distal end of the guidewire. In other embodiments, the depth of each notch can be 50% or less of the width of the guidewire tip. For example, in some embodiments, the depth of each notch can be about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, or about 50% of the width of the guidewire tip. In some embodiments, the depth of each notch can be about 11% to about 14%, about 16% to about 19%, about 21% to about 24%, about 26% to about 29%, about 31% to about 34%, about 36% to about 39%, about 41% to about 44%, or about 46% to about 49% of the width of the guidewire tip. Indeed, in some embodiments, not all notches within a plurality of notches need have the same depth; the depths of each notch may vary. In one embodiment, multiple notches can be co-located and not exceed 50% of the width of the tubular element. In other embodiments, multiple notches can be co-located and can be greater than 50% of the width of the tubular element. In embodiments with co-located notches, the notches can be about 25% of the circumference of the tubular element body. In embodiments with co-located notches, the notches are co-located, allowing the joint to move in both degrees of freedom.

[0031] The above-mentioned path-providing guide may further have an intermediate portion, in which the stiffness of the proximal portion is greater than the stiffness of the intermediate portion, and the stiffness of the intermediate portion is greater than the stiffness of the distal portion.

[0032] The stiffness of each portion of the pathway-providing guide is controllable by the relative axial, lateral, and rotational alignments of the plurality of tubular elements and the stroke of the tendon, wherein the proximal portion of the pathway-providing guide corresponds to a length of the pathway-providing guide including a first portion of the inner tubular element, a first portion of the intermediate tubular element without a set of notches, and a first coaxially aligned portion of the outer tubular element having a set of notches; the intermediate portion of the pathway-providing guide corresponds to a length of the pathway-providing guide including a second portion of the inner tubular element, a second portion of the intermediate tubular element having a set of notches, and a second coaxially aligned portion of the outer tubular element having a set of notches; and the distal portion of the pathway-providing guide corresponds to a length of the pathway-providing guide including a third portion of the intermediate tubular element having a set of notches and a third coaxially aligned portion of the outer tubular element having a set of notches.

[0033] In some embodiments, the present invention is part of an overall guidewire system, located only in the distal portion to provide beneficial trackability control. That is, the present invention need not incorporate inventive features from start to finish, but rather is more like a "quick connect" to the end of another device. Thus, the present invention can be "retrofitted" into a conventional setup to provide the beneficial capabilities of the present invention to that conventional system.

[0034] In another exemplary embodiment of the present invention, a steerable guidewire system comprises a route-providing guide having a proximal portion and a distal portion, the route-providing guide configured to position a distal end of the guidewire at a destination, and a controller operably connected to the route-providing guide, the route-providing guide and controller configured to cooperate, simultaneously and independently, to control the curvature of the distal portion of the route-providing guide and to control the arc length of the distal portion of the route-providing guide.

[0035] The pathway providing guide can include a plurality of coaxially aligned tubular elements and a tendon connected to one of the tubular elements, and the control unit can be configured to perform one or more of controlling the relative axial alignment, lateral alignment, and rotational alignment of the tubular elements, and controlling the stroke of the tendon.

[0036] The stiffness of the proximal portion of the pathway-providing guide may be greater than the stiffness of the distal portion thereof.

[0037] In another exemplary embodiment of the present invention, a robotically steerable guidewire system comprises a pathway-providing guide comprising at least three tubular elements: an inner tubular element having an inner channel, a first intermediate tubular element having rigid features along at least a portion of its length, a second intermediate tubular element (and potentially other intermediate tubular elements) having rigid features along at least a portion of its length, and an outer tubular element having rigid features along at least a portion of its length. As noted above, in this embodiment, the pathway-providing guide can include multiple intermediate tubular elements.

[0038] A control module is operably connected to the pathway-providing guide, the control module being configured to laterally displace the relative position of the inner tubular element with respect to the first intermediate tubular element, rotationally displace the relative position of the first intermediate tubular element with respect to the outer intermediate tubular element, and laterally displace the relative position of the outer tubular element with respect to the first intermediate tubular element, wherein one or more of the displacements of the tubular elements results in at least three stiffness zones along the length of the pathway-providing guide, a proximal zone having a greater stiffness than an intermediate zone, the intermediate zone having a greater stiffness than a distal zone, and wherein a guidewire is operably configured to traverse the length of the pathway-providing guide and be directed to a destination via the variable flexibility and arc length of the distal zone of the pathway-providing guide.

[0039] In another exemplary embodiment of the present invention, a method for steering a tip of a guidewire along a tortuous path to a destination includes feeding the guidewire through a path-providing guide having a distal portion configured to exit the tip of the guidewire, and simultaneously and independently controlling the curvature of the distal portion of the path-providing guide and the arc length of the distal portion along the tortuous path.

[0040] The path-providing guide may include a plurality of coaxially aligned tubular elements and a tendon connected to one of the tubular elements, and the simultaneously and independently controlling may include one or more of controlling the relative axial alignment, controlling the relative lateral alignment, and controlling the relative rotational alignment of the tubular elements, and controlling the stroke of the tendon.

[0041] These and other aspects, features, and advantages of the claimed invention will become apparent from the following detailed description of preferred embodiments and aspects taken in conjunction with the following drawings, although variations and modifications may be made thereto without departing from the spirit and scope of the novel concepts of the present disclosure.

[0042] Implementations, features, and aspects of the disclosed technology are described in detail herein and are considered a part of the claimed disclosed technology. Other implementations, features, and aspects can be understood with reference to the following detailed description, the accompanying drawings, and the claims. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or similar elements of an embodiment. Reference is now made to the accompanying drawings and flow diagrams, which are not necessarily drawn to scale. [Brief explanation of the drawings]

[0043] [Figure 1] FIG. 1 is a block diagram of an exemplary computer system architecture 100, according to an exemplary embodiment. [Figure 2] FIG. 2 is a schematic diagram of the present invention according to an exemplary embodiment showing the various tubular elements and actuation modules used to control a tendon and a plurality of coaxial tubular elements. [Figure 3] FIG. 3 is a diagram illustrating segments and portions of a route-providing guide, according to an exemplary embodiment. [Figure 4] Figure 4A shows that controlling the tendon stroke X1 and joint length X2 allows for variable curvature. Figure 4B illustrates that controlling X1 and X2 while advancing the actuation module X4 allows for leader-follow operation. Figure 4C shows that the outer tubular element is independently advanced X3 to advance further into the target vasculature while maintaining the curvature at the location of the vessel tortuosity. [Figure 5] Figure 5A shows the coaxial tubes and dimensions according to an exemplary embodiment, and Figure 5B shows the actuation stages showing the individual linear motors for controlling the guidewires according to an exemplary embodiment. [Figure 6] 6A-6C show demonstrations of the present invention according to exemplary embodiments that achieve various curvatures with different arc lengths X2. [Figure 7] FIG. 7 illustrates a schematic diagram of a flexure joint and a cross-sectional view of a notch, according to an exemplary embodiment. [Figure 8]FIG. 8 shows the geometry of the coaxial tube structure in a straight configuration. [Figure 9] FIG. 9 shows the geometry of the coaxial tube structure at curvature κ=1 / δ. [Figure 10] FIG. 10 is a graph of the stress-strain curve of a Nitinol tendon. [Figure 11] FIG. 11 is a graph showing the κ-X1 relationship described below for several values ​​of X2. [Figure 12] FIG. 12 illustrates a cross section of three segments of the robot, along with a schematic diagram of each segment with inertia values, in accordance with an illustrative embodiment. [Figure 13] FIG. 13 is a graph showing the coupling estimate κtot (as a percentage of the outer diameter of each tube) for various middle and outer tube depths. [Figure 14] FIG. 14 is a graph showing the experimental results of the κ-Ft relationship, which will be described later. [Figure 15] Figures 15A, 15B, and 15C show three samples with intermediate and outer tubes of varying depths, demonstrating various bonds between the bending and non-bending segments. [Figure 16] FIG. 16 illustrates a cross section of three segments of the robot, along with a schematic of each segment with inertia values, in accordance with an illustrative embodiment. [Figure 17] Figure 17A shows the leader-following behavior of a guidewire relative to a given reference path in free space, and Figure 17B shows a demonstration of leader-following behavior at δ=22.2 mm. [Figure 18] Figure 18A shows that the guidewire is advanced to the bifurcation of the straight path. Figures 18B-18D show that, given Xref, the guidewire can be advanced along either of the channels at the bifurcation. The dot indicates the tip of the guidewire. [Figure 19] Figures 19A-19D show the advancement of the outer tube over the inner tube after successful crossing of the vessel bifurcation (δ = 17.2 mm). DETAILED DESCRIPTION OF THE INVENTION

[0044] Although preferred exemplary embodiments of the present disclosure are described in detail, it should be understood that other exemplary embodiments are contemplated. Accordingly, the present disclosure is not limited in scope to the details of construction and the arrangement of components set forth in the following description or illustrated in the drawings. The present disclosure is capable of other exemplary embodiments and of being practiced or carried out in various ways. Moreover, in describing preferred exemplary embodiments, specific terminology is used for the sake of clarity.

[0045] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise.

[0046] Also, in describing the preferred exemplary embodiments, terminology is used for the sake of clarity, and each term is intended to have the broadest meaning as understood by one of ordinary skill in the art and to include all technical equivalents that operate in a similar manner to accomplish a similar purpose.

[0047] Ranges can be expressed herein as from "about" or "approximately" one particular value and / or to "about" or "approximately" another particular value. When such a range is expressed, another exemplary embodiment includes from the one particular value and / or to the other particular value.

[0048] Use of terms such as "comprising" or "including" means that at least the specified compounds, elements, particles, or method steps are present in a composition or article or method, but does not exclude the presence of other compounds, materials, particles, or method steps, even if such other compounds, materials, particles, or method steps have the same function as the specified one.

[0049] It should also be understood that the reference to one or more method steps does not preclude the presence of additional or intervening method steps between those explicitly identified steps. Similarly, the reference to one or more components in a device or system does not preclude the presence of additional or intervening components between the explicitly identified components.

[0050] Aspects of the disclosed technology may be implemented using at least some of the components shown in computing device architecture 100 of FIG. 1. As shown, the computing device architecture includes a central processing unit (CPU) 102, on which computer instructions are processed, and a display interface 104, which acts as a communications interface and provides functionality for rendering video, graphics, images, and text on a display. In some exemplary embodiments of the disclosed technology, display interface 104 may be directly connected to a local display, such as a touchscreen display associated with the mobile computing device. In another exemplary embodiment, display interface 104 may be configured to provide data, images, and other information for an external / remote display that is not necessarily physically connected to the mobile computing device. For example, a desktop monitor may be utilized to mirror graphics and other information presented on the mobile computing device. In some exemplary embodiments, display interface 104 may communicate wirelessly with the external / remote display, for example, via a Wi-Fi channel or other available network connection interface 112.

[0051] In an exemplary embodiment, network connection interface 112 may be configured as a communications interface and may provide functionality for rendering video, graphics, images, text, other information, or any combination thereof, on a display. In one example, the communications interface may include a serial port, a parallel port, a general-purpose input / output (GPIO) port, a game port, a universal serial bus (USB), a micro USB port, a high-definition multimedia (HDMI) port, a video port, an audio port, a Bluetooth port, a near-field communication (NFC) port, another similar communications interface, or any combination thereof. In one example, display interface 104 may be operatively coupled to a local display, such as a touchscreen display, associated with the mobile device. In another example, display interface 104 may be configured to provide video, graphics, images, text, other information, or any combination thereof, for an external / remote display not necessarily connected to the mobile computing device. In one example, a desktop monitor may be utilized to mirror or augment graphical information that may be presented on the mobile device. In another example, display interface 104 may wirelessly communicate to an external / remote display via network connection interface 112, such as a Wi-Fi transceiver.

[0052] Computing device architecture 100 may include a keyboard interface 106 that provides a communications interface to a keyboard. In an exemplary embodiment, computing device architecture 100 may include a presence-aware display interface 108 for connecting to a presence-aware display 107. According to some exemplary embodiments of the disclosed technology, presence-aware display interface 108 may provide a communications interface to various devices, such as a pointing device, a touchscreen, a depth camera, etc., which may or may not be associated with a display.

[0053] Computing device architecture 100 may be configured to allow a user to capture information into computing device architecture 100 using input devices via one or more of the input / output interfaces (e.g., keyboard interface 106, display interface 104, presence-aware display interface 108, network connection interface 112, camera interface 114, sound interface 116, etc.). The input devices may include a mouse, trackball, directional pad, trackpad, touch-sensitive trackpad, presence-aware trackpad, presence-aware display, scroll wheel, digital camera, digital video camera, webcam, microphone, sensor, smart card, etc. Additionally, the input devices may be integrated with computing device architecture 100 or may be separate devices. For example, the input devices may be an accelerometer, magnetometer, digital camera, microphone, and light sensor.

[0054] An exemplary embodiment of computing device architecture 100 may include antenna interface 110, which provides a communications interface to an antenna, and network connectivity interface 112, which provides a communications interface to a network. As described above, display interface 104 may communicate with network connectivity interface 112 to provide information for display on a remote display, for example, not directly connected to or attached to the system. In some embodiments, a camera interface 114 is provided that acts as a communications interface and provides functionality for capturing digital images from a camera. In some embodiments, sound interface 116 is provided as a communications interface for converting sound into electrical signals using a microphone and converting the electrical signals into sound using a speaker.

[0055] According to an exemplary embodiment, random access memory (RAM) 118 is provided, and computer instructions and data may be stored in a volatile memory device for processing by CPU 102. According to an exemplary embodiment, computing device architecture 100 includes read-only memory (ROM) 120, in which unchanging low-level system code or data for basic system functions such as basic input / output (I / O), startup, or receiving keystrokes from a keyboard is stored in a non-volatile memory device. According to an exemplary embodiment, computing device architecture 100 includes storage medium 122 or other suitable type of memory (e.g., RAM, ROM, programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), magnetic disk, optical disk, floppy disk, hard disk, removable cartridge, flash drive, etc.), in which files are stored, including operating system 124, application programs 126 (e.g., including a web browser application, a widget or gadget engine, and / or other applications as appropriate), and data files 128. According to an exemplary embodiment, computing device architecture 100 includes a power supply 130 that provides suitable alternating current (AC) or direct current (DC) to electrically powered components.

[0056] According to an exemplary implementation, computing device architecture 100 includes a telephony subsystem 132 that enables device 100 to send and receive sounds over a telephone network. Each component communicates with CPU 102 via bus 134.

[0057] According to an exemplary embodiment, the CPU 102 has a suitable structure as a computer processor. In one configuration, the CPU 102 may include two or more processing units. The RAM 118 interfaces with the computer bus 134 to provide rapid RAM storage for the CPU 102 during execution of software programs, such as an operating system, application programs, and device drivers. More specifically, the CPU 102 loads computer-executable process steps into the RAM 118 from the storage medium 122 or other media to execute the software programs. Data may be stored in the RAM 118, and the data may be accessed by the computer CPU 102 during execution. In one exemplary configuration, the device architecture 100 includes at least 98 MB of RAM and 256 MB of flash memory.

[0058] The storage medium 122 itself may include several physical drive units, such as a redundant array of independent disks (RAID), a floppy disk drive, a flash memory, a USB flash drive, an external hard disk drive, a thumb drive, a pen drive, a key drive, a high-density digital versatile disk (HD-DVD) optical disk drive, an internal hard disk drive, a Blu-ray optical disk drive, or a holographic digital data storage (HDDS) optical disk drive, an external mini dual in-line memory module (DI MM), a synchronous dynamic random access memory (SDRAM), or an external micro DI MM SDRAM. Such computer-readable storage media enable a computing device to access computer-executable process steps, application programs, and the like stored on removable and non-removable memory media to download data from or upload data to the device. Computer program products, such as those utilizing a communication system, may be tangibly embodied in the storage medium 122, which may comprise a machine-readable storage medium.

[0059] According to one exemplary embodiment, the term computing device, as used herein, may be a CPU or may be conceptualized as a CPU (e.g., CPU 102 of FIG. 1 ). In this exemplary embodiment, the CPU may be coupled, connected, and / or communicate with one or more peripheral devices, such as a display. In another exemplary implementation, the term computing device, as used herein, may refer to a mobile computing device, such as a smartphone, tablet computer, or smartwatch. In this exemplary embodiment, the computing device may output content to its local display and / or speakers. In another exemplary embodiment, the computing device may output content to an external display device, such as a TV or external computing system (e.g., via Wi-Fi).

[0060] 2 and 3, the robotically steerable guidewire system 200 can include a path-providing guide 210 including a proximal portion 212 and a distal portion 214, the path-providing guide 210 configured to position the distal end of the guidewire at a target location. The path-providing guide 210 has an operable length that may be described below as the combined length of the consecutive segment lengths of segment A (SA), segment B (SB), and segment C (SC). The operable length of the path-providing guide 210 may also be described as the combined length of the consecutive segment lengths of the non-bending portion (NBP) and the bending portion (BP).

[0061] The control / actuation module 300 is operably connected to the path providing guide 210. The path providing guide 210 and the control module 300 are configured to cooperate, simultaneously and independently, to control the (amount of) curvature κ of the distal portion BP of the path providing guide 210 and to control the available length SA of bending of the distal portion BP of the path providing guide 210.

[0062] The pathway-providing guide 210 comprises a plurality of coaxially aligned tubular elements 220 and a tendon 222 connected to one of the tubular elements. As used herein, "coaxial" and / or "coaxially aligned" are relative terms and do not require idealized perfect axial alignment of the elements. The present invention is operable over a range of stretchable alignments, including "nested" configurations of tubular elements.

[0063] It will also be understood by those skilled in the art that the terms "stiffness" and / or "stiff / rigid" can be described using other relative terms, such as "compliant" and / or "flexible." These relative terms can be used to describe components of the invention, for example, components or portions of components that have increasing stiffness or decreasing flexibility along their length, from different directions. Alternatively, being more compliant means having less stiffness.

[0064] The control unit 300 is configured to control (1) the relative axial alignment of the tubular elements 220, and / or (2) how one other tubular element is centrally aligned within another tubular element, and / or (3) the relative lateral alignment of the tubular elements 220, and / or (4) the nesting or lateral displacement of one tubular element relative to another tubular element, and / or (5) the relative rotational alignment of the tubular elements 220, and / or (6) the stroke of the tendon 222.

[0065] Control of the relative axial alignment of tubular elements 220 depends on whether one fits snugly within the other. For example, if the tolerance between the outer wall of the innermost tubular element and the inner wall of the tubular element outside it is negligible, then the amount that the innermost tubular element is "off-center" is negligible. Alternatively, if the difference between the diameters of the tubular elements is such that they are equally oval in cross section, then there is a greater tolerance for the relative axial alignment of the tubular elements away from the common axis of rotation.

[0066] Controlling the relative lateral alignment of tubular elements 220 is less dependent on the tolerances described above. As long as one tubular element can "slide" relative to the other, the length by which one tubular element can expand or contract relative to the other can be fairly easily controlled.

[0067] Controlling the relative rotational alignment of the tubular element 220 allows for fine tuning of the stiffness of the distal portion of the pathway-providing guide 210, allowing for out-of-plane (3-dimensional) movement of the guidewire.

[0068] Controlling the relative rotational alignment of tubular elements 220 is relevant when the outer / inner geometries of the tubular elements are different. For example, if the innermost tubular element has a uniform circular cross-section along its length, a uniform wall thickness, and is constructed of the same material throughout, and the outer tubular element has a uniform circular cross-section along its length large enough to accommodate the innermost tubular element, a uniform wall thickness, and is constructed of the same material throughout, then the relative rotational alignment of the tubular elements will not be affected by the rotation of any one tubular element. The tubular elements will not have effective characteristics with respect to each other's rotational conditions.

[0069] However, if one tubular element has a set of features that do not have rotational symmetry, how one tubular element rotates relative to another tubular element will affect the relationship between the tubular elements.

[0070] In an exemplary embodiment, at least one tubular element 220 has a stiffness feature that enables the stiffness of the proximal portion NBP of the pathway providing guide 210 to be greater than the stiffness of the distal portion BP of the pathway providing guide 220.

[0071] The tubular element 220 can include an inner tubular element 224 having an inner channel, an intermediate tubular element 226 having a stiffening feature 232 along at least a portion of its length, and an outer tubular element 228 having a stiffening feature 234 along at least a portion of its length.

[0072] The tubular elements 224, 226, 228 each have suitable cross-sectional dimensions so that the guide wire is rotationally and laterally displaceable within the inner channel of the inner tubular element 224, the inner tubular element 224 is rotationally and laterally displaceable within the intermediate tubular element 226, and the intermediate tubular element 226 is rotationally and laterally displaceable within the outer tubular element 228.

[0073] The intermediate tubular element 226 has a defined length from the proximal end to the distal end, and the stiffness feature 232 may include a set of notches 242 that begin at an intermediate position of the intermediate tubular element 226 (the proximal end of the SB) and extend to the distal end of the intermediate tubular element 226 (the distal end of the SA).

[0074] The outer tubular element 228 has a length defined from the proximal end to the distal end, and the stiffness feature 234 may include a set of notches 244 beginning at an intermediate position of the outer tubular element 228 (the proximal end of the SC) and extending to the distal end of the outer tubular element 228 (the distal end of the SA).

[0075] The length of the set of notches 244 in the outer tubular element 228 as shown is greater than the length of the set of notches 242 in the intermediate tubular element 226, although the length of the notch sets can vary.

[0076] The set of notches 244 in the outer tubular element 228 are preferably out of phase with the set of notches 242 in the intermediate tubular element 226, allowing the intermediate tubular element 226 to be operatively rotatable and laterally displaceable in / out of the outer tubular element 228. The set of notches are preferably, but not necessarily, out of phase with each other by 180°.

[0077] Either or both of the notch sets 242 , 244 can form a variety of notch shapes / patterns, for example, a unidirectional asymmetric notch joint between the intermediate tubular element 226 and the outer tubular element 228 .

[0078] The telescoping of tubular elements 224, 226, 228 by controlling tendon 222, the relative rotational alignment of stiffness features 232, 234, and the overall displacement of system 200 define both the reach of the guidewire and its ability to be navigated through arcuate pathways, e.g., the vasculature. System 200 generally embodies the tortuosity capabilities of the present invention by varying the local stiffness of pathway-providing guide 210.

[0079] Those skilled in the art will appreciate that the present invention may include more than two tendons and more than two tubular elements, and the additional components may extend the range and ability to follow a tortuous path.

[0080] Furthermore, it will be understood by those skilled in the art that none of the tubular elements may have a similar cross-sectional profile to one another, or that some or all of the tubular elements may have similar cross-sectional profiles to one another, and in fact, even a single tubular element need not be of uniform cross-section along its length. Multiple tubular elements can slide inside / outside of one another, can rotate inside or outside of one another, have different cross-sectional shapes from one tubular element to another, and have different cross-sectional shapes and / or dimensions along the length of a single tubular element.

[0081] The stiffness of the portion SC of the path providing guide 210 is greater than the stiffness of the portion SB of the path providing guide 210. The stiffness of the portion SB of the path providing guide 210 is greater than the stiffness of the portion SA of the path providing guide 210.

[0082] The stiffness of each portion of the path-providing guide 210 can be controlled by the relative axial alignment of the tubular elements 220, the relative lateral alignment of the tubular elements 220, the relative rotational alignment of the tubular elements 226 and 228, and the stroke of the tendon 222, where the portion SC of the path-providing guide 210 is a portion of the length of the path-providing guide that includes a first portion of the inner tubular element 224, a first portion of the middle tubular element 226 (which does not have a set of notches), and a first portion of the outer tubular element 228 (which has a set of notches 244), which are coaxially aligned.

[0083] Portion SB of the path providing guide 210 is a portion corresponding to the length of the path providing guide 210 including the second portion of the inner tubular element 224, the second portion of the intermediate tubular element 226 (having the set of notches 242), and the second portion of the outer tubular element 228 (having the set of notches 244), which are coaxially aligned, and the first and second portions of the inner tubular element 224 include the entire length of the inner tubular element 224.

[0084] Portion BP of path providing guide 210 is a portion corresponding to the length of path providing guide 210 including the third portion of intermediate tubular element 226 (having set of notches 242) and the third portion of outer tubular element 228 (having set of notches 244), which are coaxially aligned.

[0085] The coaxial tubular elements 220 allow the present invention to perform "follow the leader" operation with limited DoF within the compact space required for a guidewire. In the exemplary embodiment, the inner tubular element 224 is made of stainless steel and has a uniform cylindrical cross-section with an inner channel. In the exemplary embodiment, the middle tubular element 226 and the outer tubular element 228 are Nitinol tubes with micromachined notch patterns along at least a portion of the length of each tube.

[0086] Each tubular element has appropriate dimensions to allow it to slide within the other. To avoid collision / interference of the notches on the middle and outer tubular elements, the notches are provided with a 180° phase difference. A tendon 222 passes through inner tubular element 224 and is connected to the distal end of middle tubular element 226.

[0087] Depending on the relative positions of each tubular element and the notch pattern, in SA, the notch pattern on the middle tubular element reduces the moment of inertia and shifts the neutral axis toward the unnotched side, thereby increasing the compliance and moment arm of the tendon in this segment. However, in SB, the introduction of the stainless steel inner tubular element increases the moment of inertia of the combined structure, significantly increasing stiffness and reducing the moment arm in this segment. Finally, only the outer tubular element 228 retains the notch pattern in SC, thereby increasing stiffness in this segment.

[0088] Thus, the present invention has three segments of varying stiffness as shown, which can be broadly classified into bending portion BP (i.e., SA) and non-bending portion NBP (i.e., SB and SC) depending on the relative position of the inner tubular element 224.

[0089] 2, the control / actuation module 300 drives the pathway-providing guide 210. The tendon 222 and the inner and outer tubular elements 224, 228 are connected to drivers 302, 304, 312, respectively. In the exemplary embodiment, these drivers are linear motors.

[0090] Those skilled in the art will appreciate that all elements of the present invention, not just the motor, may be selected for a particular mode of use. For example, if the present invention is to be used in a magnetic resonance imaging (MRI) environment, the motor, tubular elements, and tendons should avoid materials that are harmful in the MRI environment.

[0091] The adaptability of the present invention is further enhanced by the type of components selected. While a linear motor can be used, many other displacement mechanisms can be used, including piezoelectric motors and rack and pinions. Additionally, while stainless steel has been useful for the inner tubular element, other materials can be used to provide the present invention with the beneficial flexibility / rigidity disclosed herein. Additionally, while Nitinol is useful for the intermediate and outer tubular elements, other materials are known that are sufficiently elastic yet rigid to embody notch-like rigidity characteristics.

[0092] The intermediate tubular element 226 may be fixed to the control / actuation module 300 itself, or may be rotationally driven by a drive 308 / gear 314 assembly that may impart rotation of the intermediate tubular element 226. Those skilled in the art will appreciate that the operational consideration is the relative rotation of the intermediate tubular element 226 and the outer tubular element 228. Thus, in alternative configurations, the outer tubular element 228 may be rotationally controlled along with the intermediate tubular element 226, which has a fixed rotation, or both elements 226, 228 may be rotationally controlled.

[0093] As shown, the actuation module has five control variables, namely, X1, X2, X3, X4, and ψ, which correspond to the stroke of the tendon, the relative distance between the inner element and the tubular element, the displacement of the outer tubular element, the displacement of the actuation module, and the rotation of the middle tubular element, respectively.

[0094] Given the control variables, the present invention can form any arc shape within geometric constraints because X1 and X2 control the curvature and arc length, respectively, of the distal portion of the path-providing guide 210 (bending segment A) (see FIG. 4A). Thus, by controlling X1 and X2 and providing a displacement X4 to the actuation module, the bending segment A can follow a curved path in the vasculature that is a function of the curvature and arc length. This allows for follow-up leader operation during guidance along a curved path (see FIG. 4B) without passive support from the vessel wall.

[0095] The outer tubular element 228 can slide and advance further along the curved intermediate tubular element 226 (see FIG. 4C ). The intermediate tubular element 226 provides a stable path for the outer tubular element 228 to reach the appropriate position as an introducer sheath, while maintaining the curvature at the curved path. The entire procedure can then be repeated at the next curved path until the final target location is reached. Thus, the present invention allows for easy insertion of a guidewire into tortuous vasculature without the need for guidewire exchange, thereby significantly shortening procedure time.

[0096] The prototype of the present invention was constructed and assembled as shown in Figure 5B. The intermediate tubular element 226 and the outer tubular element 228 were fabricated using superelastic nitinol to provide high bending capacity, and their notch patterns were machined using a femtosecond laser (WS-Flex Ultra-Short Pulse Laser Workstation, Optec, Framley, Belgium). The tendon 222 was also fabricated from nitinol to facilitate insertion into the tubular elements and ease of attachment. Finally, the inner tubular element 224 was made of stainless steel because it has higher stiffness than the intermediate and outer tubular elements. The outer tubular element 228, inner tubular element 224, and tendon 222 were connected to linear motors (Maxon Precision Motors, Massachusetts, USA, resolution: approximately 2.8 μm) to perform linear motion and slide along their respective surfaces (see Figure 5B). The stroke of the motor controls the tendon displacement X1 and the arc length X2 of the SA, thereby achieving variable curvature at several arc lengths of the SA (see Figures 6A, 6B, and 6C). The entire actuation stage 300 is mounted on a base stage using linear guides and actuated by a base linear motor 306 (to control X4). The tendon 222 is connected to a miniature force sensor to measure its tension. The dimensions of the tubular element shown in Figure 5A used in the prototype are summarized in Table I. [Table 1]

[0097] In the tested embodiment, the system was fabricated with a length (10) shorter than that of a conventional guidewire for in vitro feasibility testing.

[0098] To derive the relationship between the stroke X1 of the tendon, the desired curvature κ, and the arc length X2 of the SA, and to derive the static model of the curved portion BP of the guidewire and the coupling model of the non-bent portion NBP, consider the case of a single notched tubular element (tube) with notch depth d, notch width h, and n notches in the joint (see Figure 7). o and r i are the outer and inner radii of the tube, respectively, and the area A at the notch is created by laser micromachining. o -A i The cross section of the SiO2 film is formed (see Figure 7 (insert)).

[0099] This cross section is the area in the region

number

number

number

number

number

number

[0100] Thus, the location of the neutral axis of a tube of the present invention is given by the following equation (subscript "j" refers to the outer, middle, or inner tubular element):

number

[0101] Area A o -A i The moment of inertia of the notched segment is given by:

number

[0102] Now, from the parallel axes theorem and equation (2), the second moment of area of ​​the notched segment about the neutral axis of the pipe is given by:

number

[0103] Given the desired curvature κ and the length of the joint X2, the required bending angle is given by θ = κX2. A schematic of the bending section of the robot along various lengths and radii of the pipe is shown in Figure 8. The diameter of the tendon is t d The initial length of the tendon in this straight configuration is

number

number

[0104] When the bending segment SA of the guidewire is bent to a certain curvature κ, the inner wall of the intermediate tube forms an arc at an angle θ with a center "O" (see Figure 9). As a result, the path of the tendon through the intermediate tube is divided into two parts. The straight portion of the tendon, indicated by line segment AB in Figure 9, extends from the inner wall of the inner tube and intersects the bent portion of the intermediate tube at point "A" so that line AB is tangent to the bent curve at point "A."

[0105] The second section, shown in FIG. 9 by arc AC, is curved with the intermediate tube and has a radius r cur and extending along the inner wall of the intermediate tube having

number

number

number

number

[0106] The length of the straight part of the tendon is

number

number

[0107] Here, the applied tendon tension is F t and L total = 337.2 mm is the original "unstretched" length of the entire tendon from the tip of the robot to the actuator. E t = 53.965 GPa is the Young's modulus of the Nitinol tendon in the austenite phase and is an experimentally derived value (see Figure 10). To test the kinematic model used, κ-X1 is evaluated for several values ​​of joint length (X2) (see Figure 11).

[0108] For each experiment, the tendon tension F t The motor stroke data from the encoder was used as the ground truth for each case. Finally, for each case, the kinematic term ΔL kin are also plotted. In both cases, the tendon elongation dominates the kinematics at the joint. Furthermore, equation (5) accurately predicts the kinematics at the joint, especially for large values ​​of X2 (X2 = {37.45 mm, 32.45 mm, 27.45 mm} (Figure 11), RMSE = 0.0324 mm). The higher deviation from the model at lower X2 values ​​(X2 = 17.45 mm (Figure 11), RMSE = 0.1331 mm) can be attributed to higher friction losses due to the joint becoming stiffer as the joint length decreases.

[0109] Ideally, the design goal is that a tendon stroke of X1 will result in a curvature κ in the bending segment A (see SA in Figures 2 and 3), while the non-bending segments B and C (see SB and SC in Figures 2 and 3) will not undergo any deformation. However, due to the arrangement of the coaxial tubes within the non-bending segments and the connections between the segments, these segments will also deform slightly.

[0110] A static model for the SA and a coupling model relating the coupling effect on the joint notch depth and non-flexing segment are developed and validated. The SA (see inset in Figure 12) consists of an intermediate tube and an outer notched tube actuated by a tendon placed along the inner wall of the intermediate tube. The tendon is connected to the distal tip of the intermediate tube, so that a moment (ΔM = F t Δy n ) is applied to the entire structure, where the moment arm Δy n is the displacement between the tendon and the neutral axis of the intermediate tube at segment n (see SA, SB, and SC in Figure 12). Furthermore, actuation of the tendon causes the intermediate tube to displace and contact the outer tube (see cross section SB in Figure 12). The moment arm of the tension in the tendon is

number

[0111] In each joint, the number of notches is large (95 and 160 for the intermediate and outer tubes, respectively), so that for a single notched element in the tube, the curvature achieved by the bending element is negligible (less than 2° for a 180° bend in the joint). Furthermore, the total bending angle is assumed to be uniformly distributed over all notches, but the segment of length c between two notches (see Figure 7) does not bend at all.

[0112] Assuming uniform notch spacing within a given segment (β=h / (h+c)) is defined to represent the ratio of the width of an individual notch to the sum of the individual notched and unnotched sections in the joint. The notched and unnotched sections are uniformly repeated for a given joint segment. Note that the intermediate and outer pipes were designed with the same value of c. The Euler beam equation is then applied to the SA's κ-F t By applying this to the relationship, the following equation is obtained:

number

[0113] Since the two tubes are not bonded to each other and can slide over each other, the resulting curvature κ is caused by the sum of the inertia terms in the above equation. In equation (6), the moment of area of ​​each tube with respect to SA is

number

number

[0114] Furthermore, adding an inner tube in the SB adds an inertial term in the static model (see Figure 12).

number

[0115] The inner tube is made of 304 stainless steel, and therefore, from the manufacturer's datasheet, E inn= 200 GPa. Furthermore, since there is no notch in the inner tube, from equation (4),

number

number

[0116] Similar to the SB, the SC consists of all three tubes. However, the key difference is that in this segment, the intermediate tube is not notched (see Figure 12). The moment arm of the applied tendon tension is

number

number

[0117] where:

number

number

[0118] Figure 13 shows the (d mid ,d out ) and κ tot The relationship between the parameter (d mid ,d out ) are shown as a percentage of their corresponding outer diameter. Increasing the depth of the micromachined notches decreases the degree of coupling between the segments. However, this separation of the segments due to the decreased degree of coupling is achieved at the expense of stiffness at the tip of the robot.

[0119] (d mid ,d out Three samples corresponding to various values ​​of σ were microfabricated (see Figures 15A, 15B, and 15C). As expected, the highest coupling was found in "G1" (Figure 15A), whereas negligible coupling was found in "G2." While fitting "G1" is sufficiently stiff but highly coupled to be guided within the vasculature, sample "G2" is extremely flexible and can only be used when large curvatures are required with minimal interaction with the vessel wall. As a result, fitting "G3" (Figure 15C) was selected as the most likely candidate to achieve high curvatures with minimal coupling and high stiffness.

[0120] Next, the static model of SA was verified for sample "G3" (see equation (6)). The prototype of the invention uses a guidewire with κ-F t To obtain the relationship, several curvatures were operated to be achieved (see Figure 14). First, for various curvatures and arc lengths of SA (X2 = {37.45 mm, 32.45 mm, 27.45 mm, 22.45 mm, 17.45 mm}), κ-F t Note that the relationship remains constant and can be approximated for this geometry by a linear fit (RMSE=0.064N). Using this linear fit and equation (6), we can obtain

number

[0121] From equations (5) and (6), the direct relationship between κ and X1 is derived for a given X2 as follows:

number

[0122] Therefore, κ can be directly controlled by X1 without the need for dynamical information.

[0123] Equation (10) and G = [δ, θ, a1, a2], which indicates the geometric information of the blood vessels. T Based on the G curve (see Figure 16), the variables (i.e., X1, X2, X3, X4) are controlled to follow a specific path through the vasculature. The G curve of the vasculature can be identified using non-invasive imaging observations such as fluoroscopy or MRI, and the curve is assumed to have a constant curvature.

[0124] The intervention distance s in the form of a path variable along the centerline of the vessel is fed into the kinematic / static model with G and the reference X of the n-th linear actuator ref.n (n=1, 2, 3, 4). Therefore, according to s in each vascular section (i.e., P1, P2, or P3 in FIG. 16), X ref =[X ref.1 ,X ref.2 ,X ref.3 ,X ref.4 ] T becomes:

number

[0125] 17A and 17B show the xy coordinates of the tip following given reference curved paths with various curvatures by using the proposed control scheme in free space (where a1 and a2 are assumed to be zero), selected from the EM tracker in a single tracking run. Paths with low curvature (average L 2 A relatively small error occurs for paths with high curvature (average L 2 The error increases significantly at distance 14.66 mm. This is believed to arise mainly from the coupling of SB and SC, which shifts the coordinates of SA. However, it should be noted that this robot is intended to operate in a constrained space, and this problem due to coupling can be compensated for in a constrained space such as the vasculature.

[0126] To verify the present invention, -1 ~0.015mm -1 Vascular phantom models replicating the pediatric carotid artery, aortic arch, and aortic bifurcation with curvatures ranging from 0.01 to 0.02 were 3D printed with various paths (see Figures 18A to 18D). The guidewire was fed into a linear path (s∈P1 in Equation (11)) and formed a curved shape with a constant curvature to follow a given reference path at the bifurcation (s∈P2 in Equation (11)).

[0127] When the distal tip of the robot reaches the end of the curved path, the outer tube slides over the curved intermediate tube (s∈P3 in Equation (11)) and advances further (see Figures 19A to 19D). This provides a stable path for the intermediate tube to reach the next operating point as an introducer sheath. The entire procedure is repeated on the next curved path.

[0128] Thus, the intervention and guidance capabilities of the guidewire of the present invention were successfully demonstrated in bifurcated sections with various curvatures in a vascular phantom model, which prevents the common kinking and breakage problems of guidewires in current clinical practice without guidewire replacement, and provides a stable and rapid intervention process for treating CVD in a minimally invasive manner.

[0129] The present invention is a coaxially aligned steerable guidewire robot designed using coaxial tubes (three in the exemplary embodiment) and tendons (one in the exemplary embodiment). Independent control of bend arc length and curvature allows the robot to follow vessel curvatures of various lengths and bend angles with a unique following leader motion.

[0130] Kinematic and static models of the robot were derived, and a control algorithm based on these models was proposed to control the present invention. This prototype robot has a diameter compatible with commercially available guidewires. The performance of the present invention was evaluated using a vascular phantom model in free space. The robot successfully passed through various high-curvature vascular structures. The present invention may also be navigable in a three-dimensional phantom vasculature with vascular stiffness characteristics and a pulsatile blood flow system under fluoroscopic guidance.

[0131] While particular embodiments of the disclosed technology have been described in connection with what are presently considered to be the most practical embodiments, it is to be understood that the disclosed technology is not to be limited to the disclosed embodiments, but on the contrary, it is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.

[0132] Examples are used herein to disclose particular embodiments of the disclosed technology, including the best mode, and also to enable those skilled in the art to practice particular embodiments of the disclosed technology, including making and using any device or system, and performing any incorporated methods. The patentable scope of particular embodiments of the disclosed technology is defined in the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they contain equivalent structural elements that do not differ substantially from the literal language of the claims.

Claims

1. a telescoping arrangement of a plurality of telescoping elements; a tendon passing through an inner channel of an inner tubular element of the plurality of telescoping elements and attached to a distal end of a middle tubular element of the plurality of telescoping elements; and a path-providing guide including a proximal portion and a distal portion. a control unit operably connected to the route providing guide; The route providing guide and the control unit cooperate to: the curvature of the distal portion of the pathway-providing guide by using the tendon; or A system configured to independently control at least one of an arc length of the distal portion of the pathway-providing guide by a relative position of the inner tubular element in a lateral displacement of the plurality of nestable elements.

2. 10. The system of claim 1, the pathway-providing guide is configured to position a distal end of a guidewire at a target location; The route providing guide and the control unit cooperate to: a curvature of the distal portion of the path-providing guide; and an arc length of the distal portion of the pathway-providing guide simultaneously and independently.

3. 10. The system of claim 1, the control unit is selected from the group consisting of an automatic control unit and a manually operable control unit; The system is selected from the group consisting of a robotically steerable guidewire system having said automatic control, and a manually steerable guidewire system having said manually operable control.

4. 4. A system according to any one of claims 1 to 3, The control unit controlling the relative axial alignment of the plurality of nestable elements; controlling relative lateral alignment of the plurality of nestable elements; controlling the relative rotational alignment of the plurality of nestable elements; controlling the stroke of the tendon; The system is configured to perform at least one of the following:

5. 5. The system of claim 4, The system wherein the path-providing guide has a variable stiffness profile along a length of the path-providing guide.

6. 6. The system of claim 5, A system wherein the variable stiffness profile is continuously variable along the length of the path-providing guide.

7. a path-providing guide having a proximal portion and a distal portion, the path-providing guide having a variable stiffness profile along a length of the path-providing guide; a control unit operably connected to the route providing guide; The route providing guide and the control unit cooperate to: the curvature of the distal portion of the path-providing guide; or configured to independently control at least one arc length of the distal portion of the pathway-providing guide; the variable stiffness profile is discretely variable along a length of the path-providing guide; A system wherein along one or more portions of the path-providing guide, the one or more portions have substantially the same stiffness along the length of the one or more portions.

8. Route guide and a control unit operably connected to the route providing guide; The route providing guide includes: a plurality of coaxially aligned tubular elements; a tendon; the pathway-providing guide includes a proximal portion and a distal portion and is configured to position the distal end of the guidewire at a target location; The control unit controlling the relative axial alignment of the plurality of tubular elements; controlling the relative lateral alignment of the plurality of tubular elements; controlling the relative rotational alignment of the plurality of tubular elements; controlling the stroke of the tendon; configured to perform one or more of: The route providing guide and the control unit cooperate to: the curvature of the distal portion of the path-providing guide; or The system is configured to independently control at least one arc length of the distal portion of the pathway-providing guide.

9. Route guide and a control unit operably connected to the route providing guide; The route providing guide includes: a plurality of coaxially aligned tubular elements; a tendon; the pathway-providing guide includes a proximal portion and a distal portion and is configured to position the distal end of the guidewire at a target location; The control unit controlling the relative axial alignment of the plurality of tubular elements; controlling the relative lateral alignment of the plurality of tubular elements; controlling the relative rotational alignment of the plurality of tubular elements; controlling the stroke of the tendon; and The route providing guide and the control unit cooperate to: a curvature of the distal portion of the path-providing guide; and an arc length of the distal portion of the path-providing guide simultaneously and independently; The plurality of coaxially aligned tubular elements comprises: an inner tubular element having an inner channel; an intermediate tubular element having stiffness features along at least a portion of its length that provide a varying stiffness profile along the length of the path-providing guide; an outer tubular element having stiffness features along at least a portion of its length; Each of the plurality of tubular elements comprises: a guidewire is rotationally and laterally displaceable within the inner channel of the inner tubular element; the inner tubular element is rotationally and laterally displaceable within the intermediate tubular element; The system has suitable cross-sectional dimensions such that the intermediate tubular element is rotationally and laterally displaceable within the outer tubular element.

10. 10. The system of claim 9, the intermediate tubular element has a length defined from a proximal end to a distal end, and the stiffness feature comprises a set of notches beginning at an intermediate location of the intermediate tubular element and extending to the distal end of the intermediate tubular element; the outer tubular element has a length defined from a proximal end to a distal end, and the stiffness feature comprises a set of notches beginning at an intermediate location of the outer tubular element and extending to the distal end of the outer tubular element; A system wherein the set of notches in the outer tubular element are out of phase with the set of notches in the intermediate tubular element, thereby allowing the intermediate tubular element to be operatively rotatable and laterally displaceable within the outer tubular element.

11. 11. The system of claim 10, the sets of notches form a unidirectional asymmetric notch joint in the intermediate tubular element and the outer tubular element; The phase difference between both sets of notches is 180°.

12. 11. The system of claim 10, the path-providing guide further comprises a middle portion; a stiffness of a proximal portion of the pathway-providing guide greater than a stiffness of an intermediate portion thereof; A system wherein the stiffness of the intermediate portion of the pathway-providing guide is greater than the stiffness of the distal portion thereof.

13. 9. The system of claim 8, The route providing guide and the control unit cooperate to: a curvature of the distal portion of the path-providing guide; and an arc length of the distal portion of the path-providing guide simultaneously and independently; A system wherein the stiffness of each portion of the path-providing guide is controllable by the relative axial alignment, relative lateral alignment, and relative rotational alignment of the plurality of tubular elements and the stroke of the tendon.

14. 1. A robotically steerable guidewire system comprising: At least three tubular elements, namely an inner tubular element having an inner channel; a first intermediate tubular element having stiffness features along at least a portion of its length that provide a varying stiffness profile along the length of the pathway-providing guide; an outer tubular element having stiffness features along at least a portion of its length; a route guide including a control module operably connected to the route providing guide; The control module laterally displacing the relative position of the inner tubular element with respect to the first intermediate tubular element; Rotationally displacing the relative position of the first intermediate tubular element with respect to the outer tubular element; configured to laterally displace the relative position of the outer tubular element with respect to the first intermediate tubular element; one or more of the displacements of the at least three tubular elements result in stiffness zones along a length of the pathway-providing guide, the proximal zone having a higher stiffness than an intermediate zone, the intermediate zone having a higher stiffness than a distal zone; The system is configured such that the guidewire is steered across the length of the pathway-providing guide and is guided to the target location by the variable flexibility and arc length of the intermediate and distal regions of the pathway-providing guide.

15. a path-providing guide comprising a proximal portion and a distal portion; a control unit operably connected to the route providing guide; the pathway-providing guide is configured to have a guidewire passing through the pathway-providing guide such that a distal end of the guidewire is configured to exit the pathway-providing guide; The route providing guide and the control unit cooperate to: a curvature of a distal portion of the pathway-providing guide; an arc length of a distal portion of the pathway-providing guide; and a steerable guidewire system configured to simultaneously and independently control:

16. 16. The system of claim 15, The route providing guide includes: a plurality of coaxially aligned tubular elements; a tendon connected to one of the plurality of tubular elements; Equipped with The simultaneously and independently controlling controlling the relative axial alignment of the plurality of tubular elements; controlling the relative lateral alignment of the plurality of tubular elements; controlling the relative rotational alignment of the plurality of tubular elements; controlling the stroke of the tendon; 1. A system comprising:

17. 17. The system of claim 16, The path-providing guide has a variable stiffness profile along its length.

18. 17. The system of claim 16, The plurality of coaxially aligned tubular elements comprises: an inner tubular element having an inner channel; an intermediate tubular element having stiffness features along at least a portion of its length that provide a varying stiffness profile along the length of the path-providing guide; an outer tubular element having stiffness features along at least a portion of its length; Each of the plurality of tubular elements comprises: the guidewire is rotationally and laterally displaceable within the inner channel of the inner tubular element; the inner tubular element is rotationally and laterally displaceable within the intermediate tubular element; A system wherein the intermediate tubular element has suitable cross-sectional dimensions such that it is rotationally and laterally displaceable within the outer tubular element.

19. 20. The system of claim 18, the intermediate tubular element has a length defined from a proximal end to a distal end, and the stiffness feature comprises a set of notches beginning at an intermediate location of the intermediate tubular element and extending to the distal end; the outer tubular element has a length defined from a proximal end to a distal end, and the stiffness feature comprises a set of notches beginning at an intermediate location of the outer tubular element and extending to the distal end; the length of the set of notches in the outer tubular element is greater than the length of the set of notches in the intermediate tubular element; A system wherein the set of notches in the outer tubular element are out of phase with the set of notches in the intermediate tubular element, thereby allowing the intermediate tubular element to be operatively rotatable and laterally displaceable within the outer tubular element.

20. 20. The system of claim 19, the sets of notches form a unidirectional asymmetric notch joint in the intermediate tubular element and the outer tubular element; The phase difference between both sets of notches is 180°.

21. 21. The system of claim 20, the path-providing guide further comprises a middle portion; a stiffness of a proximal portion of the pathway-providing guide greater than a stiffness of an intermediate portion thereof; A system wherein the stiffness of the intermediate portion of the pathway-providing guide is greater than the stiffness of the distal portion thereof.

22. 22. The system of claim 21, the stiffness of each portion of the path-providing guide is controllable by the relative axial, lateral, and rotational alignments of the plurality of tubular elements and the stroke of the tendon; the proximal portion of the path-providing guide corresponds to a length of the path-providing guide including a first portion of the inner tubular element, a first portion of the intermediate tubular element without a set of notches, and a first portion of the outer tubular element with a set of notches, all of which are coaxially aligned; the intermediate portion of the path-providing guide corresponds to a length of the path-providing guide, including the second portion of the inner tubular element, the second portion of the intermediate tubular element having a set of notches, and the second portion of the outer tubular element having a set of notches, which are coaxially aligned, and the first portion and the second portion of the inner tubular element include the entire length of the inner tubular element; The system is configured such that the distal portion of the pathway-providing guide is a portion corresponding to a length of the pathway-providing guide that includes a third portion of the intermediate tubular element having a set of notches and a third portion of the outer tubular element having a set of notches that are coaxially aligned.

23. 13. The system of claim 12, the stiffness of each portion of the path-providing guide is controllable by the relative axial, lateral, and rotational alignments of the plurality of tubular elements and the stroke of the tendon; the proximal portion of the path-providing guide corresponds to a length of the path-providing guide including a first portion of the inner tubular element, a first portion of the intermediate tubular element without a set of notches, and a first portion of the outer tubular element with a set of notches, all of which are coaxially aligned; the intermediate portion of the path-providing guide corresponds to a length of the path-providing guide, including the second portion of the inner tubular element, the second portion of the intermediate tubular element having a set of notches, and the second portion of the outer tubular element having a set of notches, which are coaxially aligned, and the first portion and the second portion of the inner tubular element include the entire length of the inner tubular element; The system is configured such that the distal portion of the pathway-providing guide is a portion corresponding to a length of the pathway-providing guide that includes a third portion of the intermediate tubular element having a set of notches and a third portion of the outer tubular element having a set of notches that are coaxially aligned.

24. 16. The system of claim 15, The route providing guide includes: a plurality of coaxially aligned tubular elements; a tendon connected to one of the plurality of tubular elements.

25. 16. The system of claim 15, the path-providing guide has a variable stiffness profile along its length; The simultaneously and independently controlling Controlling the relative axial alignment of a plurality of coaxially aligned tubular elements; Controlling the relative lateral alignment of a plurality of coaxially aligned tubular elements; Controlling the relative rotational alignment of a plurality of coaxially aligned tubular elements; or controlling the stroke of a tendon connected to one of the plurality of tubular elements; 1. A system comprising:

26. 26. The system of claim 25, The plurality of coaxially aligned tubular elements comprises: an inner tubular element having an inner channel; an intermediate tubular element having stiffness features along at least a portion of its length that provide a varying stiffness profile along the length of the path-providing guide; an outer tubular element having stiffness features along at least a portion of its length.

27. 27. The system of claim 26, Each of the plurality of tubular elements comprises: the guidewire is rotationally and laterally displaceable within the inner channel of the inner tubular element; the inner tubular element is rotationally and laterally displaceable within the intermediate tubular element; A system wherein the intermediate tubular element has suitable cross-sectional dimensions such that it is rotationally and laterally displaceable within the outer tubular element.

28. 28. The system of claim 27, The system, wherein the intermediate tubular element has a length defined from a proximal end to a distal end, and the stiffness feature comprises a set of notches beginning at an intermediate location of the intermediate tubular element and extending to the distal end.

29. 29. The system of claim 28, The outer tubular element has a length defined from a proximal end to a distal end, and the stiffness feature comprises a set of notches beginning at an intermediate location of the outer tubular element and extending to the distal end.

30. 30. The system of claim 29, A system wherein the length of the set of notches in the outer tubular element is greater than the length of the set of notches in the intermediate tubular element.

31. 31. The system of claim 30, A system wherein the set of notches in the outer tubular element are out of phase with the set of notches in the intermediate tubular element, thereby allowing the intermediate tubular element to be operatively rotatable and laterally displaceable within the outer tubular element.

32. 32. The system of claim 31, The sets of notches form a unidirectional asymmetric notch joint in the intermediate tubular element and the outer tubular element.

33. 33. The system of claim 32, The phase difference between both sets of notches is 180°.

34. 34. The system of claim 33, The route-providing guide further comprises an intermediate portion.

35. 35. The system of claim 34, The system wherein the stiffness of the proximal portion of the pathway-providing guide is greater than the stiffness of the intermediate portion thereof.

36. 36. The system of claim 35, A system wherein the stiffness of the intermediate portion of the pathway-providing guide is greater than the stiffness of the distal portion thereof.

37. 37. The system of claim 36, A system wherein the stiffness of each portion of the path-providing guide is controllable by the relative axial alignment, relative lateral alignment, and relative rotational alignment of the plurality of tubular elements and the stroke of the tendon.

38. 38. The system of claim 37, the proximal portion of the pathway-providing guide is a portion corresponding to a length of the pathway-providing guide including a first portion of the inner tubular element, a first portion of the intermediate tubular element without a set of notches, and a first portion of the outer tubular element with a set of notches, all of which are coaxially aligned.

39. 39. The system of claim 38, the intermediate portion of the path-providing guide is a portion corresponding to a length of the path-providing guide, including the second portion of the inner tubular element, the second portion of the intermediate tubular element having a set of notches, and the second portion of the outer tubular element having a set of notches, all of which are coaxially aligned, and the first and second portions of the inner tubular element comprise the entire length of the inner tubular element.

40. 40. The system of claim 39, the distal portion of the pathway-providing guide is a portion corresponding to the length of the pathway-providing guide including a third portion of the intermediate tubular element having a set of notches and a third portion of the outer tubular element having a set of notches, which are coaxially aligned.

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