Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M25/00—Catheters; Hollow probes
  • A61M25/01—Introducing, guiding, advancing, emplacing or holding catheters
  • A61M25/0105—Steering means as part of the catheter or advancing means; Markers for positioning
  • A61M25/0133—Tip steering devices
  • A61M25/0138—Tip steering devices having flexible regions as a result of weakened outer material, e.g. slots, slits, cuts, joints or coils
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M25/00—Catheters; Hollow probes
  • A61M25/0043—Catheters; Hollow probes characterised by structural features
  • A61M25/0054—Catheters; Hollow probes characterised by structural features with regions for increasing flexibility
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M25/00—Catheters; Hollow probes
  • A61M25/01—Introducing, guiding, advancing, emplacing or holding catheters
  • A61M25/0105—Steering means as part of the catheter or advancing means; Markers for positioning
  • A61M25/0133—Tip steering devices
  • A61M25/0136—Handles therefor
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M25/00—Catheters; Hollow probes
  • A61M25/01—Introducing, guiding, advancing, emplacing or holding catheters
  • A61M25/0105—Steering means as part of the catheter or advancing means; Markers for positioning
  • A61M25/0133—Tip steering devices
  • A61M25/0147—Tip steering devices with movable mechanical means, e.g. pull wires
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M25/00—Catheters; Hollow probes
  • A61M25/01—Introducing, guiding, advancing, emplacing or holding catheters
  • A61M25/0105—Steering means as part of the catheter or advancing means; Markers for positioning
  • A61M25/0133—Tip steering devices
  • A61M25/0152—Tip steering devices with pre-shaped mechanisms, e.g. pre-shaped stylets or pre-shaped outer tubes
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B17/00234—Surgical instruments, devices or methods for minimally invasive surgery
  • A61B2017/00292—Surgical instruments, devices or methods for minimally invasive surgery mounted on or guided by flexible, e.g. catheter-like, means
  • A61B2017/003—Steerable
  • A61B2017/00305—Constructional details of the flexible means
  • A61B2017/00309—Cut-outs or slits
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
  • A61B17/00—Surgical instruments, devices or methods
  • A61B2017/00831—Material properties
  • A61B2017/00867—Material properties shape memory effect
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61M—DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROM THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR
  • A61M25/00—Catheters; Hollow probes
  • A61M25/01—Introducing, guiding, advancing, emplacing or holding catheters
  • A61M25/0105—Steering means as part of the catheter or advancing means; Markers for positioning
  • A61M25/0133—Tip steering devices
  • A61M2025/0161—Tip steering devices wherein the distal tips have two or more deflection regions

Definitions

• 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.
• 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.
• DTM double torque motor
• 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.
• 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.
• the author provides further improvements to steerable devices, including those used as medical devices for body lumens as described more in detail herein.
• a flexible and steerable device with adjustable floppiness 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.
• the STT effect may be either reduced or inhibited entirely, depending on the need.
• 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.
• the mechanical stop member is further defined as the “stop ring”.
• 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.
• 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.
• the flexible distal portion may be formed with helical grooves or other slotted patterns.
• 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.
• 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.
• 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.
• 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.
• a controlled that is to say, desired
• free bending that is to say, bending resulting from external forces imparted to the wall sections
• tangential rotation 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.
• 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.
• 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.
• 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.
• 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.
• the tangential width of separate bridges making the spine may grow from small to larger when moving from the distal tip to more proximal.
• 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.
• 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.
• 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.
• 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.
• 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.
• the covering includes a transmitter or receiver.
• a slippery coating layer is applied to one or both of the tube surfaces in order to reduce the friction, which makes manipulating easier.
• a slippery coating layer may be made of a hydrophilic material.
• 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.
• 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.
• 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.
• 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.
• the device 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.
• 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.
• the device can also be pushed easily over a guidewire without pulling the guidewire out of a target lumen.
• 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.
• 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.
• 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.
• the device can be inserted over a central guidewire.
• 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.
• 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.
• 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.
• 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.
• additional devices for example for flushing, aspiration or any other means.
• 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
• 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.
• 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.
• materials making up the controller tool and sheath can be made from polymers, metals or similar structural constituents, or combinations thereof.
• the metal can be a shape-memory metal with shape memory, super-elasticity, or linear elasticity.
• 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.
• the devices disclosed herein may be used in non-medical applications as well as medical applications.
• 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.
• 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.
• steerable devices may be used in oil wells, water wells, gas wells or the like, as well as for space applications or transportation systems.
• the devices may be configured as an endoscope for medical and non-medical use.
• a steerable device also referred to herein as an assembly
• 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.
• 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.
• 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.
• 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.
• steerable devices there are several options to making steerable devices according to the present disclosure.
• devices be used in medical procedures, comprising minimal invasive devices, surgical tools, steerable drilling tools, instruments, rotating instruments, placement of pacemaker leads and implants.
• 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.
• 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
• FIG. 2 depicts a perspective view of an inner tube with a counterclockwise helical cut and at its distal end a stop ring;
• 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;
• 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;
• 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;
• FIG. 6 depicts a cross section view of the tubes of FIG. 5, with the spines placed opposite each other;
• 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;
• 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;
• 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;
• FIGS. 1 la through l id depict cross section views of the tubes of FIGS. 10a through 10c in different relative tangential positions
• 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.
• 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.
• 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
• 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.
• 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.
• 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.
• Wl the length
• All bridges 74 are located on a line which is parallel with the major longitudinal axis of the outer tube 71.
• 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.
• 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.
• 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.
• the inner tube 72 may be replaced with a solid wire.
• adjustable steerability and floppiness may be achieved when the flexible and steerable device is configured as a stylet or guidewire.
• 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.
• 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.
• the distal end of the outer tube is not in contact with the stop ring 73.
• relative tangential rotation over an angle a is possible.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• FIG. 7 a simplified view on the entire device 70 in the state of FIG. 6 is shown.
• 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.
• 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.
• 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.
• each of outer tube 171 and inner tube 172 defines clockwise and counterclockwise uninterrupted helical cuts, respectively.
• 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.
• 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.
• 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.
• 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
• FIGS. 9a through 9f details of various loading conditions on the respective zone 2 of the tubes 171, 172 of FIG. 8 are shown.
• FIGS. 9a, 9c and 9e additional details of zone 2 of the outer tube 171 are shown.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• zone 1 the kerf width is made variable, being small around the locks 181, 182 and larger at the opposing side.
• 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.
• 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.
• the single locks 181 assume the position shown in FIG. 9e.
• this series of locks functions in a similar way as the bridges 74, 75 in FIG. 7.
• 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.
• 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.
• the inner tube 272 has locks 274 in zone 1 and locks 277 and 278 in the other zones.
• 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.
• 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.
• the tip zone is in its most floppy state.
• 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.
• 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.
• 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.
• 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.
• 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.
• top flanges 292 and 293 close together without any tangential deviation, thereby reducing or eliminating the tendency of the distal tip to revolve.
• 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
• bottom flanges 298 and 299 close together without any tangential deviation, thereby reducing or eliminating the tendency of the distal tip to revolve.
• 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.
• 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.
• a claim that states "at least one of A, B and C" 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.
• 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.
• each intervening number therebetween with the same degree of precision is explicitly contemplated.
• 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.

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• 2023
  • 2023-08-11 EP EP23817504.6A patent/EP4568730A1/de active Pending
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