Flexible and steerable device with adjustable floppiness

Abstract

A steerable endoluminal device with adjustable floppiness, a method of making an endoluminal device and a method of using an endoluminal device. The device includes two concentric flexible tubes with a slot pattern and a series of male / female interlocking members that can prevent tangential rotation when activated. A stop ring and a controller that has two different steering functions allow floppiness adjustment through simple tangential rotation between the inner and outer tubes, while an increasing relative axial movement between the tubes causes a gradual change in the mechanical characteristics of the proximal sections and bending of the device distal end.

Description

[0001] FLEXIBLE AND STEERABLE DEVICE WITH ADJUSTABLE FLOPPINESS

[0002] TECHNICAL FIELD

[0003] The present disclosure relates generally to a flexible and steerable device, and more particularly to such device that has cooperating concentric tubes that can be moved longitudinally relative to each other in order to change the bending radius of a distal end of the device, while relative rotational movement results in an adjustable change of the floppiness of the device that is also adjustable when longitudinal forces are applied in a wall of the device.

[0004] BACKGROUND ART

[0005] In US 6,428,634 and WO 9638594, the author of the present disclosure describes medical devices made of ternary shape memory alloys with super-elastic plateau stresses that are much higher than for binary alloys, which can be used for achieving higher output forces at identical dimensions, or smaller dimensions at similar output forces. Such alloys can be used for multiple properties, including the higher plateau stresses if in the super-elastic mode, or higher elastic modus if cold worked.

[0006] In US 5,885,258, US 6,780,175, US 7,037,321, US 8,052,670 and US 8,377,037, the author of the present disclosure describes numerous kinds of medical instruments based on slotted memory metal tubing for making flexible and steerable devices. Some examples describe super- elastic tubular baskets for making expandable reamers with cutting struts.

[0007] In US 7,776,062 and US 8,382,786, the author of the present disclosure describes a self- centering distal anchoring section in a catheter or guidewire which is actuated by a proximal biasing spring that holds two concentric tubes in a preferred axial position. Changing the length of the biasing spring causes a change in the geometry of the distal section. There is a place for applying additional devices through the inner tube or over the outer tube, dependent on the application.

[0008] In US 5,607,435, the author of the present disclosure describes a medical tool with a nitinol inner tube that has a curved shape when it leaves the distal end of a surrounding catheter tube. This enables movement of the distal end with several degrees of freedom, when the longitudinal movements are combined with a rotation around the length axis. One example mentioned is a steerable drill bit. Upon withdrawal of the inner nitinol tube into the surrounding catheter tube the device is brought into a straight shape again for insertion and removal purposes.

[0009] In US 10,441,746 and US 11,241,557 the author of the present disclosure describes a catheter or guidewire with a helical cut with variable width in the tubular wall. Changing the length of this device by a central pull wire or tube causes a controlled tangential revolving of the distal end without the need of having proximal rotation. This is defined as self-torque tip (STT), resulting in a single torque motor (STM).

[0010] In WO 2023 / 084305 the author of the present disclosure describes a self-revolving endoluminal device with a double torque motor (DTM), having two concentric helical-cut tubes connected to a proximal tool. Changing the relative axial position at the proximal end causes simultaneous tangential rotation of both cooperating distal ends, which are provided with drill bit segments. When the outer tube is pulled back, both drill bit segments can be separated, so there is no permanent connection at the distal end.

[0011] The author of the present disclosure notes with particularity that the various embodiments disclosed in the prior patents by the author of the present disclosure are hereby incorporated in their entirety into the present disclosure and may be used in combination with the device of the present disclosure or with components thereof.

[0012] US 8,684,953, US 9,138,566, US 10,456,556, US 11,141,566 and US Published Application 2020 / 0282181 disclose a steering tool for steering medical devices through body lumens. The steering tool has an internal tube disposed inside an external tube. The internal and external tubes are arranged for longitudinal axial movement relative to one another. The distal end of the internal tube is fixedly joined to the distal end of the external tube. One or both of the internal and external tubes is slotted near the distal end thereof. The longitudinal axial movement causes bending of the distal ends of the tubes. The steering tool provides a distal tip which combines steerability, flexibility and torqueability. The tool eliminates the need for pull / push wires. Many of these features were previously disclosed in the aforementioned US 8,377,037 and US 8,382,786 wherein a flexible sheath and a tubular control element are fixedly connected at their distal ends and wherein relative longitudinal movement at the proximal end by means of a tool causes a reconfigurable distal tip section to bend or stretch, amongst others.

[0013] Some of the aforementioned tubular devices have a permanent connection at or near the distal end of the tubes, such as through welding, ultrasonic welding, thermal bonding, soldering, adhesive bonding, molding or other approaches. Such fixed connectivity causes the respective devices to have specific floppiness in certain bending planes, but complete freedom to change this floppiness after bonding is lost. Moreover, only the steerability by relative axial movement remains. DISCLOSURE OF INVENTION

[0014] By the present disclosure, the author provides further improvements to steerable devices, including those used as medical devices for body lumens as described more in detail herein.

[0015] According to an aspect of the present disclosure, a flexible and steerable device with adjustable floppiness is disclosed. The device includes an external (also referred to herein as an outer) tube and an internal (also referred to herein as an inner) tube disposed inside the external tube. The device is constructed to permit relative axial longitudinal and tangential rotation between the inner and outer tube. Each of the internal and external tubes may be formed as a helically coiled structure with a pitch that defines a series of axially adjacent wall sections with a slot therebetween. At least some of the axially adjacent wall sections define a spine-forming male / female interlocking member pair that allows both a controlled degree of free bending of the wall sections in a specific bending plane and a controlled degree of tangential rotation. The geometry of the male / female interlocking member pair selectively prevents any substantial tangential rotation between adjacent wall sections when an interference fit is formed between a male locking member of the male / female interlocking member pair and a female locking member of the male / female interlocking member pair; such fit can be made to occur or increase during periods of outer tube axial compression and inner tube axial tension. By such construction and selective use of at least one of the compression and tension, the STT effect may be either reduced or inhibited entirely, depending on the need.

[0016] In one form, a distal portion of the inner tube is not fixedly joined to a distal portion of the outer tube. The distal end of the inner tube is provided with a short stop ring with a diameter similar to the outer diameter of the outer tube such that the stop ring can take the axial force exerted by the outer tube when it is pushed forward relative to the inner tube. In this state, the pushing force exerted by the outer tube creates a pulling force to the inner tube. The axial force can also be taken by a pin, mounted in the wall of the inner tube or any other member disposed on the outer wall of the inner tube, as long as this member can stop the free axial sliding of the outer tube over the inner tube. For the ease of description, the mechanical stop member is further defined as the “stop ring”.

[0017] In one form, the slots are transverse slets and are formed at least near the distal end of the inner and outer tubes. In this way, the longitudinal axial movement causes bending of the distal ends of the tubes. In one form, the inner tube may include a flexible portion distal of the stop ring, the flexible distal portion being more flexible than other portions of that tube. In one form, the flexible distal portion may be formed with helical grooves or other slotted patterns. In general, the passive flexibility of at least a portion of the tubes may be achieved by use of a specific cutting pattern that maintains torsional stability in order to have a one-to-one transmittal of torque from their proximal to distal ends. In one form, the cutting pattern differs from the pattern of the distal end, which has to have preferential bending in specific planes, preferably controlled from the proximal end. Within the present disclosure, the control of various movements of the flexible and steerable device with adjustable floppiness is through user manipulation, such as through a separate tool as discussed herein. For example, it will be appreciated that a user may adjust or otherwise manipulate the inner and outer tubes relative to one another in order to produce a controlled (that is to say, desired) amount of one or both of free bending (that is to say, bending resulting from external forces imparted to the wall sections) and tangential rotation. It will be appreciated that many forms of endoluminal devices, including those that are described by the present author in the aforementioned references, may be used in conjunction with the devices disclosed herein.

[0018] The various features disclosed herein are relevant for a steerable tip section with active bending, which has a short length compared to the remainder of the device. Such a distal section may have a length of about 1-3 cm and can be actively bent by steering over an angle of 0 to 180 degrees, or even more. The desired radius of curvature may be constant or variable over the length of the tip. This is presented in the following text and figures.

[0019] In one form, these bendable tubes define a spine-like longitudinal structure and a series of rings or helical coil segments connected by short bridges, shape-fit locks or hinges, thus forming an asymmetrical spine. Within the context of the present disclosure, the term “spine” is used for representing the longitudinal support between the separate rings or loops that are connected thereto in order to work as one part. The gap that forms the slots between adjacent rings can be closed during bending with the spine at the convex side, or further opened when the spine is at the concave side. Each tube may be provided with a single spine, or eventually two or more spines, their location depending on the amount of flexibility and desirable bending direction.

[0020] Care must be taken to not place too many spines will reduce the flexibility in specific bending planes, which may cause problems during navigation through tortuous anatomy, in which the desired plane of bending is not known yet before.

[0021] In general it is preferable that the flexibility at the distal end is maximized by using smaller lengths between adjacent ring or coil segments. More proximal the distance may be increased or the cutting pattern is changed in other ways to achieve the same gradient in stiffness. For example, the tangential width of separate bridges making the spine may grow from small to larger when moving from the distal tip to more proximal. Alternatively, the tangential distance between two cooperating spines in the same tubular wall may be small near the distal end and larger near the proximal end, thus changing the stiffness over the length.

[0022] The spine may be parallel with the length (that is to say, longitudinal) axis of the device, but if it is used in combination with a helical cutting pattern the device may bend out of one plane. In such case the spine may have a small tangential offset per loop that compensates for this out- of-plane bending in a manner similar to that of FIG. 9 in US 10,441,746.

[0023] In accordance with an embodiment of the disclosure, the spine is formed by a series of male / female locks that can take axial pull and push forces without allowing any relative tangential rotation between adjacent tube sections. In one form, a single male lock that extends from one side of the slot that is formed between axially adjacent wall sections engages with a single female lock that is formed in the other side of the slot to form a male / female interlocking member pair. This will ensure that bending of the distal end of the device takes place in a single plane without having the burden of the STT effect.

[0024] The repositioning of spines by relative rotation of inner and outer tube changes the overall floppiness of the distal end in specific bending planes, also of the proximal sections. Furthermore, exerting an axial force between inner and outer tubes causes a dramatic change in rigidity of the proximal sections, thus increasing the pushability of the entire device. In addition, intermediate axial forces between outer and inner tube cause corresponding intermediate changes in mechanical behavior of the device, thereby enabling a gradual adjustment of the desirable characteristics.

[0025] In accordance with an embodiment of the present disclosure, a covering is provided over the flexible distal portion or over the entire tube. The covering may or may not be softer than the flexible distal portion. In one form, the covering includes a transmitter or receiver.

[0026] It is an embodiment of the present disclosure that a slippery coating layer is applied to one or both of the tube surfaces in order to reduce the friction, which makes manipulating easier. Such a layer may be made of a hydrophilic material.

[0027] In accordance with an embodiment of the present disclosure, at least one of the tubes includes most proximal portions, middle portions and most distal portions, wherein the most distal portions are more flexible than the middle and the most proximal portions, and the most proximal portions are more axially stiff than the middle and the most distal portions. There is also provided in accordance with an embodiment of the present disclosure a proximal controller tool with clamps that can move both tubes independently in axial and tangential directions. In the bending mode the controller tool holds the inner tube disposed inside the outer tube, the inner and outer tubes being arranged for longitudinal axial movement relative to one another, wherein a distal portion of the outer tube is pushed against the stop ring near a distal portion of the inner tube. At least one of the inner and outer tubes is formed with transverse slots near the distal end thereof, and wherein the longitudinal axial movement causes bending of the distal ends of the tubes, and wherein the inner tube may include a flexible distal portion distal to the stop ring, the flexible distal portion being more flexible than other portions of that tube.

[0028] The controller tool can be provided with indicia that give information about the relative axial position of the distal ends, as well about their relative tangential position. A simple controller makes use of a proximal clamp that holds the inner tube plus a distal clamp that holds the outer tube. The distal clamp may be connected to a thumb-controlled wheel that either is pushed distally for bending or rotated to change the relative tangential position between the tubes. In the latter case the outer tube is first pulled back over a distance to disengage it from the stop ring of the inner tube. When pushing the outer tube against the distal stop ring of the inner tube, it depends of the relative positions of the spines in both tubes how the distal bending behavior will be. When for example both tubes have one spine each and when the spine in the outer tube will be 180 degrees opposite the spine in the inner tube, the push force will cause bending. The outer surface of the spine of the inner tube will become concave, while the outer surface of the spine of the outer tube will become convex. Steering by bending takes place merely in one plane, defined by the two spines. When the device is used in this mode, it has a certain stiffness in one plane and it may be difficult to push it through tortuous anatomy because of its lack of floppiness. This is overcome by rotation of the tubes in the following way.

[0029] Before or during insertion of the steerable device the relative axial position of the tubes can be changed by pulling the outer tube away from the distal stop ring. This is done by moving the two holder clamps on the controller tool towards each other far enough to disengage the distal ends. Then, while holding the outer tube still, the controller tool (which is clamped to the inner tube) can be rotated over any angle between 0 and 360 degrees, to change the relative tangential position of the inner and outer spines. This will result in a dramatic change of the floppiness of the steerable device, which is now very flexible. Now it can easily be inserted or pushed through tortuous anatomy and follow the path with reduced mechanical friction, thus preventing damage to the inner wall of the lumen. In this most floppy state the device can also be pushed easily over a guidewire without pulling the guidewire out of a target lumen. Whenever a curvature of the distal end is needed, the controller tool can be used to rotate both tubes relatively back into the “optimal bending mode” with the spines opposite to each other, for example. Pushing apart the tube holder clamps on the controller tool will then slide the distal end of the outer tube against the stop ring of the inner tube and controlled bending starts.

[0030] Optionally, the controller tool can be locked in axial and / or tangential positions, and the indicia will give the operator information of the actual state of the distal end of the steerable device.

[0031] In one embodiment the inner and outer tube both have a helical shape with a cutting pattern in the tube wall which may be helical over the entire length, but also only over a part of the distal end. The remainder of the length may be un-slotted, or have a cutting pattern that is not helical. If the slots in inner and outer tube are oriented parallel in the same direction, it is possible that sliding is hindered when the slot edges hook up. When the helical slot in the outer tube is oriented clockwise and for the inner tube counterclockwise, this problem is overcome. Sliding becomes smooth then, both in axial as well as tangential directions.

[0032] It is another embodiment of the present disclosure that the device can be inserted over a central guidewire.

[0033] In another embodiment of the present disclosure, the device is inserted through a separate guiding catheter, which has an inflatable cuff or balloon to close the gap between the outer surface of the catheter and the inner wall of the body lumen. This enables a safe aspiration and suction of released debris.

[0034] It is yet another object of the present disclosure to provide a unitized guiding catheter having a uniform, smooth, continuous outer diameter along its length.

[0035] In another object of the disclosure the inner lumen of the assembled device has a smooth, cylindrical surface that allows the easy insertion of additional devices through the lumen from the proximal side to the distal side.

[0036] It is another object of the disclosure that the assembled device has a smooth, cylindrical outer surface that allows the easy insertion of additional devices from the proximal side to the distal side over its outer surface.

[0037] It is also an obj ect of the disclosure that the proximal side of the inner tube is provided with a hub or luer-like connector for attaching additional devices, for example for flushing, aspiration or any other means. While the present disclosure emphasizes a device for guiding catheter applications, it will be appreciated by those skilled in the art that but the same principle can be used for a range of different exoluminal or endoluminal applications, including catheters, micro-catheters, steerable tips, endoscopes, laser systems, ablation systems, stents, filters, angioplasty balloons, drains, dilators, filters, baskets, filterbaskets, anchors, floating anchors, occlusion devices, guidewires, stylets, electrodes, leads, drill bits and angioplasty devices for opening chronic occlusions, drains, catheter sheaths for use with catheter introducers, a (contrast) fluid or drug infusion catheter, placing coils in aneurisms or related medical devices. Likewise, the device may further include one or more endoluminal devices that can slidably fit over a sheath. The endoluminal device can be at least any of a catheter, micro-catheter, steerable tip, endoscope, stent, filter, angioplasty balloon, drain, dilator, filter, basket, filterbasket, anchor, floating anchor, occlusion device, guidewire, stylet, electrode, lead, drain, drilling device, catheter sheath for use with catheter introducers or a fluid or drug infusion catheter, as well as combinations of the above. Similarly, the device itself may be a catheter, micro-catheter, steerable tip, stent, filter, angioplasty balloon, drilling device, drain, dilator, basket, filterbasket, anchor, floating anchor, occlusion device, guidewire, stylet, electrode, lead, drain, catheter sheath for use with catheter introducers or a drug infusion catheter, or combination of the above. Furthermore, materials making up the controller tool and sheath can be made from polymers, metals or similar structural constituents, or combinations thereof. In a particular form, the metal can be a shape-memory metal with shape memory, super-elasticity, or linear elasticity. Such shape memory metals may be made as a binary alloy, but also a ternary alloy or even contain more elements. These materials are especially valuable for applications requiring reconfigurable or related components.

[0038] As previously mentioned, the devices disclosed herein may be used in non-medical applications as well as medical applications. For devices using the principles according to the disclosure that are used in other fields than medical, different sizes and different techniques for providing the slots that create the locks may be used. Examples are waterjet cutting, etching, abrasive cutting, EDM, photo etching and others. In another embodiment, there is no cutting of slots, for example if a technique such as 3-dimensional printing is used to form the device with an integrated pattern of slots. In another form of the device, steerable devices may be used in oil wells, water wells, gas wells or the like, as well as for space applications or transportation systems. In yet another form, the devices may be configured as an endoscope for medical and non-medical use.

[0039] In general, it is advantageous if the distal end of a steerable device (also referred to herein as an assembly) is relatively compliant or floppy, while the majority of the length should be kink resistant, pushable, bendable and able to transmit one-to-one torsional forces from the proximal to distal end in order to maneuver the assembly accurately. The tubular sheath can be chosen from any wire or hypotube material suitable for guidewire or catheter applications. One specifically suitable material is superelastic nitinol, a nickel -titanium alloy with shape-memory properties that is well-known for its flexibility, pushability, biocompatibility and kink resistance. In one configuration, the majority of the length of the tubular sheath may be made of metal while the distal section may be made from a relatively soft and flexible material. If improved visibility for MRI or related radio-opacity is needed, additional markers of materials like gold, platinum, silver, tungsten, iridium or the like may be used at specific locations on the tube, at least near the distal end, where the stop ring is located. Other material choices include metals and related materials for improved strength, stiffness or visibility for MRI or radio-opacity. Nitinol does not have to be in its superelastic mode, but can also be used in its linear elastic state, caused by a different thermomechanical production process.

[0040] If needed, additional rigidity may be provided, such as through the inclusion of a polymer, glue viscoelastic or related material that may be used to fill the gaps defined by one or more of the slots that are formed by the axially adjacent wall sections. This additional rigidity has the effect of resisting change of length and tangential shear between the axially adjacent wall sections. In another form, the additional rigidity may be in the form of an eccentric reinforcement element that is secured through at least one of dipping, extrusion, welding, crimping, brazing, gluing and embedding in a cover material that is disposed around the outer tube.

[0041] There are several options to making steerable devices according to the present disclosure. Moreover, it is an object of the present disclosure that devices be used in medical procedures, comprising minimal invasive devices, surgical tools, steerable drilling tools, instruments, rotating instruments, placement of pacemaker leads and implants. It is also an object of the present disclosure that such devices may be used in non-medical procedures, including but not limited to exploration, completion and maintenance of oil, gas and water wells, fluid and gas transport systems, manipulators in robotics, vacuum environments, laboratory equipment and other fields. Even for the use outside of a lumen devices according to the present disclosure may be used, for example in a robot arm or in a manipulator in outer space or under water, like a manipulator arm on a submarine. One example would be an antenna for outer space applications. Other applications are the fine adjustment of parts in drones and related unmanned aerial vehicles, like for example fine adjustment of wing flaps, rudders or propeller blades.

[0042] These and additional features provided by the embodiments and aspects disclosed herein will be more fully understood in view of the following detailed description, in conjunction with the drawings.

[0043] BRIEF DESCRIPTION OF THE DRAWINGS

[0044] The embodiments set forth in the drawings are illustrative in nature and not intended to limit the subject matter defined by the claims. The following detailed description of the illustrative embodiments can be understood when read in conjunction with the following drawings, where like structure is indicated with like reference numerals and in which:

[0045] FIG. 1 depicts a perspective view of an outer tube with a clockwise helical cut and a series of bridges connecting adjacent loops forming a longitudinal spine according to an aspect of the present disclosure;

[0046] FIG. 2 depicts a perspective view of an inner tube with a counterclockwise helical cut and at its distal end a stop ring;

[0047] FIG. 3 depicts the tubes of FIGS. 1 and 2 assembled to form a concentric relationship with one another along with a distal end of the outer tube that is not in contact with the stop ring;

[0048] FIG. 4 depicts a cross section view of the tubes of FIG. 3 in a state where the two spines are located at the same angular position;

[0049] FIG. 5 depicts a perspective view of the tubes of FIGS. 1 and 2 assembled to form a concentric relationship with one another where now the spines depicted in FIGS. 3 and 4 are placed opposite each other by relative rotation between the inner and outer tubes;

[0050] FIG. 6 depicts a cross section view of the tubes of FIG. 5, with the spines placed opposite each other;

[0051] FIG. 7 depicts a schematic side view on the entire device in the state of FIG. 6, showing the proximal end of the inner and outer tube held in clamps;

[0052] FIG. 8 depicts a two-dimensional layout of the helical inner and outer tubes without uncut bridge sections and where one or more spines are formed by a series of male / female locks for a locking mechanism that is distributed over three distinct zones;

[0053] FIGS. 9a through 9f depict details of the locks of FIG. 8 where a degree of interference fitbetween the cooperating parts of the spine-forming male / female interlocking member pair change in response to selective compressive and tensile axial forces being imparted to the flexible and steerable device with adjustable floppiness; FIGS. 10a through 10c depict two-dimensional layouts of the inner and outer tubes with a single series of locks at the distal end zone and a double series of locks in the other zones;

[0054] FIGS. 1 la through l id depict cross section views of the tubes of FIGS. 10a through 10c in different relative tangential positions; and

[0055] FIGS. 12a through 12f depict details of special embodiments of locks of FIGS. 8 and 10a through 10c in unloaded and loaded states that correspond to varying degrees of interference fit between the cooperating parts of the spine-forming male / female interlocking member pair.

[0056] MODES FOR CARRYING OUT THE INVENTION

[0057] A technical difficulty to overcome relates to the poor one-to-one torque transmission from proximal to distal ends of a thin elongate tubular device (such as those used in endoluminal procedures to treat or open partly or completely obstructed arteries, veins and related body lumens in patients), particularly in such devices that have a helical construction. Thus, while helicalbased devices are simple to make and very flexible upon bending, this inability to maintain one- to-one torque transmission limits their practical use. Another technical difficulty to overcome relates to how the STT effect — if not used on purpose — can make or hinder precise manipulation of the distal end of the device. The present disclosure provides a technical solution to these problems by providing a device that permits improved tactile feedback to the operator, as well as a guiding catheter in combination with other guidewires, aspiration and flushing systems, optical systems and other medical devices.

[0058] Referring first to FIG. 1, a first tube in the form of an outer tube 71 is shown. The outer tube 71 defines a clockwise helical cut and a series of bridges 74 connecting adjacent loops, thereby forming a longitudinal spine. For the purpose of the following examples, the figures depict ahelical structure with a single spine, formed by only one row of bridges 74. Each bridge 74 has a length Wl, which equals the gap width on the opposing side. All bridges 74 are located on a line which is parallel with the major longitudinal axis of the outer tube 71. As discussed, more spines in more than one row are — although not presently shown — contemplated, and as such are within the scope of the present disclosure as well. Spines that make an angle with the length axis or spines with increasing stiffness over their length are also included. The pitch of the helical cut may be constant or variable.

[0059] The bridges 74 may be cut in the shape as depicted, or shaped as a male / female lock in a manner similar to those described in US Patents 10,441,746 and 11,241,557. In one form, the use of non- helical designs is also deemed to be within the scope of the present disclosure.

[0060] Referring next to FIG. 2, a second tube in the form of inner tube 72 is shown. The inner tube 72 includes bridges 75, with length W2 with a counterclockwise helical cut and at its distal end a stop ring 73, which may be radio-opaque. The stop ring 73 has a permanent connection with the inner tube 72 and is capable to take axial forces exerted by the outer tube 71, such as when the latter is pushed in axial direction by means of a proximal tool. The outer tube 71 will then be under compression, while the inner tube 72 is under tension. The stop ring 73 may be located at the very end of the inner tube 72, or some additional length may protrude distally beyond (not presently shown) the stop ring 73. This extra protruding length may have more floppiness than the combination of the outer and inner tubes 71, 72, or have a pre-curved shape, or may also have some gradient in stiffness over its length and may be made deflectable by remote control. This can be done with an internal pull wire, to name an example. Further it may also be provided with some radio-opaque marker band or layer.

[0061] In another form (not shown), the inner tube 72 may be replaced with a solid wire. In such case, adjustable steerability and floppiness may be achieved when the flexible and steerable device is configured as a stylet or guidewire. In such a configuration, the wire or related solid inner member functions to put the outer tube into some degree of compression, which will cause at least one effect comprising change of the floppiness, pushability and bending of the distal end of the flexible and steerable device assembly.

[0062] Referring next to FIG. 3, a schematic drawing of the tubes 71 and 72 of FIGS. 1 and 2 are shown in an assembled state to produce the flexible and steerable device with adjustable floppiness. As can be seen, the distal end of the outer tube is not in contact with the stop ring 73. As can be seen, relative tangential rotation over an angle a is possible. As long as there is a gap 76 between the distal end of the outer tube 71 and the stop ring 73, there is no axial mechanical interaction between the two tubes 71, 72, except from some friction. Therefore, it is easy to rotate the outer tube 71 tangentially over the surface of the inner tube 72 over the angle a, in order to choose a proper relative position of both spines for adjusting the needed floppiness at that moment of insertion. The difference in cutting direction of the two helices ensures a smooth sliding between inner surface of outer tube 71 and outer surface of inner tube 72, as well for relative movement in tangential as for axial movement.

[0063] Referring next to FIG. 4, a cross section of the tubes 71, 72 of FIG. 3 in a state where the two spines are located at the same angular position with relative angle a equal to 0. In this alignment, the assembly is in its most floppy state and does not have a preferential deflection direction, when external radial forces like schematic forces Fl, F2 or F3 are applied to the distal end. Some force- vectors are shown in this example, representing external forces in the X-Y plane. Force Fl will cause a decrease of the gap width W1 and W2 simultaneously and the device will bend easily in the Y-Z plane until the gaps are closed. Force F2 will cause an increase of the gap width W1 and W2 simultaneously and the device will bend easily in the Y-Z plane. Force F3 will cause bending in intermediate planes, wherein some gaps get wider and others get narrower. In general, the device is floppy enough to easily follow the anatomy in a tortuous path without excessive radial forces. In this mode, the device is not actively steering, but will just have improved uniform floppiness, allowing it to easily follow the path of a pre-inserted flexible guidewire, for example, without pulling the guidewire tip out of a target artery.

[0064] Referring next to FIG. 5, unlike the alignment of the tubes 71, 72 of FIG. 3, the spines are placed opposite each other by relative rotation over a equal to 180 degrees. The operator simply pulls the outer tube 71 out of contact with the stop ring 73 and then rotates the proximal end of the outer tube 71 relatively to the inner tube 72, or vice versa. At this stage, the axial position may be left as it is (that is to say, with the stop ring 73 out of contact with a gap 76), or the outer tube 71 may be pushed against the stop ring 73. In the first case the situation of FIG. 6 is actual, and in the latter case it will be like in FIG. 7. If needed, other angles besides 180 degrees may be used as well, but are not discussed further.

[0065] Referring next to FIG. 6, a cross section of the tubes 71, 72 of FIG. 5, wherein the spines are placed opposite each other such that a is at 180 degrees. External force F4 will cause a lot more deflection in the X-Z plane than force F5 because of the spine positions. De facto the device is very stiff when loaded in the Y direction, because the shortening of gap W2 is hindered by the inner spine, while the lengthening of gap W1 is hindered by the outer spine. This means that a device with fixed distal tube ends will not have uniform floppiness in all directions, which problem can be overcome by the various aspects of the present disclosure.

[0066] Referring next to FIG. 7, a simplified view on the entire device 70 in the state of FIG. 6 is shown. In particular, the proximal end of the inner tube 72 and outer tube 71 held in clamps Cl and C2 respectively. The relative position of clamps Cl and C2 can be changed in axial and tangential direction with a handle (not shown), while certain indicia on the handle will give information on length change AL and relative angle a between the spine positions. In the present example, the stop ring 73 is mounted to the very distal end of inner tube 72. Bridges 75 and 74 are respectively formed on the spine. In FIG. 7 the distal end is already bent and small axial movements in the pusher handle back and forth cause more or less bending of the distal end. Increasing the length L between clamps Cl and C2 with a change AL causes stronger bending, while decreasing AL causes stretching to less bending. Further decreasing over larger AL will cause complete stretching and disengagement of the stop ring 73, which enables the repositioning to the state as described in FIG. 3.

[0067] Although the rotation over angle a is controlled by rotating clamp C2 while clamp Cl is held steady, it is also possible to induce the rotation through a gearing or sliding mechanism (not shown) that transforms an axial movement into a local tangential revolving movement near the tip only. This reduces the rotational friction between the tubes 71, 72 over the major length. An example of such a mechanism is the STM, as described in patents US 10,441,746 and 11,241,557.

[0068] Referring next to FIG. 8, a two-dimensional layout of each of outer tube 171 and inner tube 172 is shown with a detail in FIGS. 9a-f. In one form, the outer and inner tubes 171, 172 define clockwise and counterclockwise uninterrupted helical cuts, respectively. In addition, each of the outer and inner tubes 171, 172 are divided into four zones along the axial dimension, numbered from 1 to 4, with zone 1 as the distal end with only a single row of male / female locks 181, 182. Zones 2 and 3 have three locks per loop, evenly distributed over the tube diameter, and zone 4 is uncut. Zone 4 is the zone where the controller tool can be attached. It will be appreciated that more zones with different types of cuts, spines and materials may be used, but is not presently shown for clarity. Although not shown in the figures, some zones may have different cutting direction, for example some clockwise helices and counterclockwise helices varied over the length of one tube.

[0069] In one form, the pitch between zones of each of the tubes 171, 172 may also be varied. For example, as shown zone 1 has a smaller pitch than in zone 2, which has a smaller pitch than in zone 3. Such varied pitch results in a gradient in flexibility along the axial dimension of their respective tubes 171, 172.

[0070] Because the helical cut is uninterrupted, there is no mechanical interaction between adjacent loops, even inside the locks 181, 182. In this way, the embodiment of FIG. 8 will have more flexibility than the spine-based version described in FIGS. 1 through 7 for similar tube dimensions and pitch. In one non-limiting example of a guiding catheter or microcatheter according to the present disclosure, an assembly is formed from a set of two concentrically- arranged Nitinol tubes 171, 172 that have outer diameters of 0.94 mm and 0.73 mm, respectively. In a configuration where the outer tube 171 has 30 loops per zone, a corresponding inner tube 172 that is cut with similar pitch angles would have about 39 loops per zone in order to achieve similar lengths for the cooperating zones in the assembly

[0071] Referring next to FIGS. 9a through 9f, details of various loading conditions on the respective zone 2 of the tubes 171, 172 of FIG. 8 are shown. Referring with particularity to FIGS. 9a, 9c and 9e, additional details of zone 2 of the outer tube 171 are shown. In FIG. 9a, the unloaded outer tube 171 is in its most floppy condition, because the helical cut is open everywhere, without any contact between adjacent loop surfaces. Even inside the locks 181 there is little or no contact that in turn leads to a relatively compliant connection between the cooperating parts of the mal / female interlocking member pair. The bending behavior of the outer tube 171 is only dependent of the tube dimensions, material and pitch.

[0072] Upon more pronounced bending, the width of the cut (that is to say, the kerf) within the locks 181 will close. The ensuing contact between engaged portions results in an interference fit that tends to obstruct further bending. In one form, the three locks per loop, distributed over 120 degrees each, will maintain the mechanical robustness of the device and prevent excessive deformations of the helical structure. Each loop will allow a certain angle of bending, and the total number of loops will determine the maximum resulting bending of the entire zone.

[0073] As shown with particularity in FIG. 9c, the floppiness of the outer tube 171 will change dramatically when a longitudinal compression force F is applied, as this closes the gaps of the kerf and makes the zone stiffer. As the pitch in zone 2 is smaller than in zone 3, zone 2 will become stiff earlier than zone 3, when the kerf is equal for both zones. If this is not desirable, the kerf width in zone 2 may be made larger than in zone 3, thus making all kerfs close at the same force F. In one form, the compression force F is generated when the outer tube 171 is pushed against a stop ring (not presently shown, but similar in construction to stop ring 73 of FIGS. 2, 3, 5 and 7) on the inner tube 172.

[0074] Referring with particularity to FIGS. 9b, 9d and 9f, pushing the outer tube 171 against the stop ring of the inner tube 172 causes an opposite tension force F, which further opens the kerf in the helix of the inner tube 172 until the male and female parts in the locks 182 engage and the kerf is partly closed inside the locks 182. This results in a similar stiffening of the inner tube 172, as compared with the stiffening of the compressed outer tube 171 by the same force F.

[0075] The bending behavior of zone 1 in each of the outer and inner tubes 171, 172 work in a manner that is generally similar to that of the embodiment of FIGS. 1 through 7. In zone 1 the kerf width is made variable, being small around the locks 181, 182 and larger at the opposing side. Referring again to FIG. 7 in conjunction with FIG. 9f, a comparison is made between the function of the interference fit that is formed by the closed locks of FIGS 9e and 9f and the uncut spine of the bridges 74, 75 in FIG. 7. In the embodiment of FIG. 7, with both spines of the tubes 71, 72 in zone 1 placed opposite to each other as shown, bending takes place by increasing the length between Cl and C2. This in turn causes the kerf of the outer tube opposing the spine to become smaller. By contrast, the single locks 181 assume the position shown in FIG. 9e. Thus, once the gaps around the male / female locks 181, 182 are closed, this series of locks functions in a similar way as the bridges 74, 75 in FIG. 7. Meanwhile, similar to the kerf opposing the spine in zone 1 of the inner tube 72 of FIG. 7 the kerf opposing the spine in FIG. 9will open farther and the single locks of the inner tube 171 will take the position of FIG. 9f. The main difference in the two embodiments is that the locks 181, 182 of the embodiment of FIGS. 9e and 9f leave more flexibility in the spine than in the bridges 74, 75 of the embodiment of FIG. 7. This is not only the case when there is no contact, but also when the gaps are closed, because the locks 181, 182 do not have to bend like the bridges 74, 75.

[0076] Referring next to FIGS. 10a through 10c, an example is given of a two-dimensional layout of an outer tube 271 and inner tube 272, both with seven distinct zones. Zone 1 is the tip zone (which in turn corresponds to a distal end of a resulting flexible and steerable device with adjustable floppiness) with a single row of shape locks. Zones 2 through 6 have two rows of shape locks per loop, each zone with a different pitch for the helical cut. Zones 7 are uncut sections where the attachment to the handling tool can take place. In the layout the stop ring that is discussed elsewhere is not shown. FIG. 10c shows a detail of the three distal zones. Outer tube 271 has a single row of locks 273, forming a flexible spine in zone 1. In the other zones two spines with locks 275 and 276 are placed with an offset of 90 degrees compared to the position of locks 273. Similarly, the inner tube 272 has locks 274 in zone 1 and locks 277 and 278 in the other zones.

[0077] The kerfs around locks 273 and 274 can be identical, but not for the entire circumference of the loop. The kerf 280 in zone 1 of the outer tube (opposite the lock) may have to be wider than the kerf 281 in the inner tube for the following reason. Upon bending zone 1 of both tubes by pushing the outer tube against the stop ring, the locks 273 will stay at the convex side, while kerf 280 will start closing at the concave side. Therefor a wider kerf is necessary for the outer tube to enable strong bending (if needed). This wider kerf is not needed for the inner tube, because it will open more by bending.

[0078] Referring now to FIGS. 1 la through l id, cross sections of tubes 271 and 272 in different relative tangential positions are given. The positions of the spines are depicted as triangles for zone 1 of each tube, while the spines for the other zones are depicted as rectangles. It will be appreciated that the triangles are not located at the same axial location as the rectangles owing to the present depiction in FIG. I la through l id of cross-sectional views along different axial portions of the flexible and steerable device with adjustable floppiness.

[0079] FIG. I la shows a position similar to FIG. 4, with the tip spines 273 and 274 placed together at angle a=0 degrees. The tip zone is in its most floppy state. In the other zones 2 through 6 spines 275 and 277 are located at oc=90 degrees, and spines 276, 278 at oc=270 degrees. This creates a situation in which the tip is most floppy, while zones 2 through 6 are merely flexible upon bending in the x-z plane.

[0080] FIG. 1 lb shows the same position for the inner tube, but with the outer tube rotated over 180 degrees, like in FIG. 6. Pushing the outer tube forward will cause the bending of the tip in zone 1. Now spines 276 and 277 line up at oc=90 degrees, with spines 275,278 lining up at a=270 degrees. The flexibility in zones 2-6 in the x-z plane remains the same, until active pushing takes place, because the slack in the locks will change then.

[0081] FIG. 11c shows an example of still another possible position, wherein the tip spines are placed on a=0 degrees for the inner tube and a=270 degrees for the outer tube. This is a position wherein the spines in zones 2 through 6 are not lined up like in FIGS. I la and 11b. Pushing the outer tube against the stop ring will cause an intermediate bending behavior for the tip, and a stiffer behavior for zones 2 through 6. While the inner tube would be able to bend in the x-z plane, this bending possibility is reduced, because the outer tube can merely bend in the y-z plane. This stiffening is even enlarged by the pushing of the outer tube and the pulling on the inner tube, because both series of locks are tightened in a manner similar to that of FIGS. 9e and 9f such that an increase in interference fit (and corresponding reduction in lock compliance) is formed. FIG. l id shows another position in which the spines act in a similar way as in FIG.11c.

[0082] It will be appreciated that all kinds of arrangements of locks, hinges, pitch angles, spine positions and numbers of locks or hinges per loop and / or zone may be used to achieve specific goals in the variable behavior of devices according to the present disclosure. Using a helical pattern is also just one embodiment of the present disclosure, besides other cutting patterns.

[0083] Referring now to FIGS. 12a through 12f, a specific type of lock geometry is depicted that will prevent or reduce the STT effect, the relative tangential rotation between adjacent loops in the helix. The locks are of the male / female type as discussed elsewhere herein. Also as previously noted, the STT effect may be undesirable in specific embodiments. The locks will ensure that the spines remain straight and parallel with the main axis of the flexible and steerable device with adjustable floppiness.

[0084] As shown in FIGS. 12a and 12b, one form of a generally helical shape within the respective outer and inner tubes is shown along with the placement of one spine-forming male / female interlocking member pair. It will be appreciated that although only a single male / female interlocking member pair is depicted for simplicity, some or all of the axially adjacent wall sections may be similarly configured.

[0085] As shown in FIG. 12c, the male lock 275 in outer tube 271 has two top flanges 292 and 293 both of which make identical angles [3 with the length axis. Similarly, two bottom flanges 294 and 295 and a neck section 283 in between, define identical angles S with the length axis. The neck section is strong enough to take the axial forces applied during manipulation of the device.

[0086] As shown in FIG. 12e, upon pushing the outer tube 271 with a force F, top flanges 292 and 293 close together without any tangential deviation, thereby reducing or eliminating the tendency of the distal tip to revolve.

[0087] As shown in FIG. 12d, the male lock 277 in the inner tube 272 has two top flanges 296 and 297, and both flanges make identical angles £ with the length axis. There are also two bottom flanges 298 and 299 and a neck section 284, and these also have identical angles c|) with the length axis.

[0088] As shown in FIG. 12f, upon pulling the inner tube with a force F, bottom flanges 298 and 299 close together without any tangential deviation, thereby reducing or eliminating the tendency of the distal tip to revolve.

[0089] The angles [3, 8, £ and may be identical, but can also be different. This may depend on various factors, including lock size, geometry of the slot, pitch angle and others. When no helical pattern is used, size and angles of lock flanges may also differ to prevent undesired tangential rotation.

[0090] This interaction of the locks in both tubes will result in a reliable, predictable, controllable bending and steering behavior, wherein the plane of bending of the tip is accurately controlled, as well as the plane of bending in the different other zones of the device.

[0091] When one of the tubes is rotated around its length axis, while the other is held still, it depends on the axial force between the two tubes what movement can be made. When this force is zero, the distal end is straight and rotation does not really have an external effect, except for the positioning of the spines. But if an axial force is applied, while the relative proximal tangential rotation takes place, the curved tip (if this option is present) will also revolve, while it is in its activated state. The friction near the stop ring will either allow some local relative tangential sliding, or (at higher force levels) the distal curved tip will revolve simultaneously.

[0092] Within the present disclosure, one or more of the following claims may utilize the term "wherein" as a transitional phrase. For the purposes of defining features discussed in the present disclosure, this term is introduced in the claims as an open-ended transitional phrase that is used to introduce a recitation of a series of characteristics of the structure and should be interpreted in like manner as the more commonly used open-ended preamble term "comprising" and its variants that do not preclude the possibility of additional acts or structures.

[0093] Within the present disclosure, terms such as "preferably", "generally" and "typically" are not utilized to limit the scope of the claims or to imply that certain features are critical, essential, or even important to the disclosed structures or functions. Rather, these terms are merely intended to highlight alternative or additional features that may or may not be utilized in a particular embodiment of the disclosed subject matter. Likewise, it is noted that the terms "substantially" and "approximately" and their variants are utilized to represent the inherent degree of uncertainty that may be attributed to any quantitative comparison, value, measurement or other representation. As such, use of these terms represents the degree by which a quantitative representation may vary from a stated reference without resulting in a change in the basic function of the subject matter at issue.

[0094] Within the present disclosure, the use of the prepositional phrase "at least one of' is deemed to be an open-ended expression that has both conjunctive and disjunctive attributes. For example, a claim that states "at least one of A, B and C" (where A, B and C are definite or indefinite articles that are the referents of the prepositional phrase) means A alone, B alone, C alone, A and B together, A and C together, B and C together, or A, B and C together.

[0095] Within the present disclosure, the following claims are not intended to be interpreted based on 35 USC 112(f) unless and until such claim limitations expressly use the phrase "means for" or “steps for” followed by a statement of function void of further structure. Moreover, the corresponding structures, materials, acts and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material or act for performing the function in combination with other claimed elements as specifically claimed.

[0096] Within the present disclosure, the singular forms “a,” “an” and “the” include plural references unless the context clearly dictates otherwise. The modifier “about” used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (for example, it includes at least the degree of error associated with the measurement of the particular quantity). The modifier “about” should also be considered as disclosing the range defined by the absolute values of the two endpoints. For example, the expression “from about 2 to about 4” also discloses the range “from 2 to 4.” The term “about” may refer to plus or minus 10% of the indicated number. For example, “about 10%” may indicate a range of 9% to 11%, and “about 1” may mean from 0.9 to 1.1. Other meanings of “about” may be apparent from the context, such as rounding off, so, for example “about 1” may also mean from 0.5 to 1.4.

[0097] F or the recitation of numeric ranges herein, each intervening number therebetween with the same degree of precision is explicitly contemplated. For example, for the range of 6 to 9, the numbers 7 and 8 are contemplated in addition to 6 and 9, and for the range 6.0 to 7.0, the number 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9 and 7.0 are explicitly contemplated.

[0098] The present description is for the purpose of illustration and is not intended to be exhaustive or limited. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the present disclosure. Aspects of the present disclosure were chosen and described in order to best explain the principles and practical applications, and to enable others of ordinary skill in the art to understand the subject matter contained herein for various embodiments with various modifications as are suited to the particular use contemplated.

[0099] Unless otherwise defined, all technical and scientific terms used herein that relate to materials and their processing have the same meaning as commonly understood by one of ordinary skill in the art. In case of conflict, the present document, including definitions, will control.

[0100] While particular embodiments have been illustrated and described herein, it should be understood that various other changes and modifications may be made without departing from the spirit and scope of the claimed subject matter. Moreover, although various aspects of the claimed subject matter have been described herein, such aspects need not be utilized in combination. It is therefore intended that the appended claims cover all such changes and modifications that are within the scope of the claimed subject matter.

Claims

CLAIMS1. A flexible and steerable device with adjustable floppiness, the flexible and steerable device comprising: an external tube; and an internal tube disposed inside the external tube to permit relative axial longitudinal movement and relative tangential rotation therebetween, wherein each of the internal and external tubes are formed as a helically coiled structure with a pitch that defines a series of axially adjacent wall sections with a slot therebetween, wherein at least some of the axially adjacent wall sections define a spine-forming male / female interlocking member pair that allows both a controlled degree of free bending of the wall sections in a specific bending plane and a controlled degree of tangential rotation, the male / female interlocking member pair defining a geometry that selectively prevents any substantial tangential rotation between adjacent wall sections when an interference fit is formed between a male locking member of the male / female interlocking member pair and a female locking member of the male / female interlocking member pair during periods of outer tube axial compression and inner tube axial tension.

2. The device of claim 1, wherein the male locking member defines bottom flanges with similar angles and a neck section in between and top flanges that make an identical angle with the length axis while with the female locking member defines bottom and top flanges that fit with similar angles to the flanges of the corresponding male locking member and wherein the neck sections are strong enough to create at least one spine that can take the axial tension and compression forces applied during manipulation of the device.

3. The device of claim 1, wherein the internal tube is provided with a stop ring at or near its distal end such that the external tube can be pulled back over the internal tube to create a gap between the stop ring and the distal end of the external tube, the gap being closable upon pushing the external tube against the stop ring to exert an axial pulling force to the internal tube, further wherein the axial compression force in the outer tube and the axial tension force in the inner tube cause at least one effect comprising a change of the floppiness and bending of the distal ends of both tubes, the mechanical behavior of the device being changeable by creating the gap followed by rotating the external tube relative to the internal tube over an angle between 0 and 360 degrees.

4. The device of claim 3, wherein upon the gap being opened in conjunction with the spines in the distal sections of outer and inner tube being circumferentially opposed to each other, the application of an axial force to the proximal tube sections causes bending of the distal section in a preferential bending plane.

5. The device of claim 4, wherein after adjusting the relative tangential position of the spines in the outer and inner tube, closure of the gap combined with an axial compression force to the outer tube causes the axial stiffness and the floppiness to be changed through preferential bending planes that in turn determines the amount of decrease of the interference fit and a final state of floppiness and amount of STT effect.

6. The device of claim 1, wherein the male / female interlocking member pair allows limited bending and tangential rotation between adjacent wall sections, when the slot between male and female lock sections is partly closed by reduced axial compression of the outer tube and reduced axial tensioning of the inner tube.

7. The device of claim 1, wherein a plurality of the male / female interlocking member pairs are situated over at least a portion of an axial dimension of the device that defines its distal end.

8. The device of claim 1, wherein different zones defined along an axial dimension of the device can have different amounts of spines each of which can be located at either similar or different tangential locations.

9. The device of claim 8, wherein the relative tangential position of the spines in the outer and inner tube sections define different stiffness in preferential bending planes of the device.

10. The device of claim 1, wherein orientation of the pitch is different in the slot of the inner relative to the outer tube.

11. The device of claim 1, wherein at least one of the slots is not helical.

12. The device of any of claims 1 to 11, further comprising a tool coupled to at least one of inner and outer tube, the tool configured with indicia to give information about the relative axial and tangential positions between both tubes to regulate a transition in the shape of at least one of the flexible sections, comprising one of the effects selected from bending, reducing flexibility, improving pushability, locking to prevent torsion, locking to stabilize the bent position of the distal end and combinations thereof.

13. The device of any of claims 1 to 12, wherein at least a part of the device is selected from the group consisting of minimal invasive devices, surgical tools, steerable drilling tools, instruments, rotating instruments, placement of pacemaker leads and implants, comprising using a catheter, micro-catheter, steerable tip, endoscope, laser system, flushing device, ablation system, stent, angioplasty balloon, drain, dilator, filter, basket, filterbasket, anchor, floatinganchor, occlusion device, wire, guide wire, stylet, electrode, lead, catheter sheath for use with catheter introducers, a fluid or drug infusion catheter, and combinations thereof.

14. The device of claim 13, further comprising an additional device cooperative with the inner tube to be slidably entered through the inner lumen defined thereby.

15. The device of claim 13, further comprising an additional device cooperative with the outer tube to be slidably entered thereover.

16. The device of claim 13, wherein a change in shape of at least one section comprises a change into at least one of an inserting and steering shape for placement into a body lumen.

17. The device of claim 13, wherein regulating the relative position of the inner and outer tubes is activated by a remotely controlled actuator or robot, working on a principle comprising a shape memory effect, hydraulic pressure, electric or magnetic signal, electromotor, direct or with a lever or mechanical gear box and combinations thereof.

18. The device of claim 1, further comprising an additional rigidity element comprising a polymer, glue or related material disposed between at least one of the slots to resist change of length and tangential shear between the axially adjacent wall sections.

19. The device of claim 18, further comprising an additional rigidity element comprising an eccentric reinforcement element that is secured through at least one of dipping, extrusion, welding, crimping, brazing, gluing and embedding in a cover material that is disposed around the outer tube.

20. A method of using the device of any of claims 1 to 19, wherein at least one of the slots is opened, followed by the step of repositioning the relative proximal ends of the tubes over a tangential angle between 0 and 360 degrees and then closing the gap again by exerting a positive axial force between outer and inner tube to cause one of the effects selected from bending, reducing flexibility in specific or all bending planes, improving pushability, locking to prevent torsion, locking to stabilize the bent position of the distal end and combinations thereof.

21. A method of using the device of any of claims 1 to 19, wherein one of the inner and outer tubes is rotated around its length axis while the gap is closed and a positive axial force is exerted to cause one of the effects selected from bending, revolving of the distal end, reducing flexibility in specific or all bending planes, improving pushability, locking to prevent torsion, locking to stabilize the bent position of the distal end and combinations thereof.

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