Steerable device for use in mammal

Abstract

The present invention relates to a steerable device (10) for use in a mammal, the steerable device (10) comprising an elongate element (12) and a flexible device tip (20), the device tip (20) comprising a tubular portion (22) and a plurality of permanent magnetic elements (30) arranged in the tubular portion (22). Each magnetic element (30) has an axial bore (40), and the axial bore forms an axial conduit (46) in which the core wire (50) extends. An axial bore (40) extends from a first axial end of the magnetic element to a second axial end opposite the first axial end. The first and second axial ends have ramps (79) allowing the magnetic elements (30) to move relative to each other, where the ramps (79) of the axial ends of adjacent magnetic elements are designed as circles having different radii or flat shapes having different angles with respect to the longitudinal axis to control bending of the device tip.

Description

Technical Field

[0001] The present invention relates to a steerable device for use in a mammal, which may be a needle, a guidewire, a catheter, an endoscope or any other flexible device designed to be inserted into a mammal, particularly into a lumen or cavity, for diagnostic or interventional purposes. Background Art

[0002] Many medical procedures require the passage of medical devices to specific locations within the body. Examples include deep brain stimulation, organ biopsies, targeted drug delivery, tumor resection, etc. Insertion and passage of such devices can be accomplished in a variety of ways, depending on the application.

[0003] When performing surgery within a body cavity (e.g., the abdomen or bladder) or within the vasculature, a flexible device is typically steered by pulling on a wire or rotating a pre-bent distal tip while simultaneously pushing proximally. There is an inherent tradeoff between the device's ability to reach the target location and its ability to advance without bending. Some proposed devices have magnetic tips that can be used with the aid of a magnetic field to make the device more flexible and the trajectory more precisely controlled.

[0004] US3,674,014 discloses a flexible catheter tip that can be guided into a selected artery of the body by a magnetic field, comprising a plurality of permanently magnetic tubular sections with spherical ends arranged in an end-to-end manner. Each pair of adjacent ends is enclosed in a tubular connector made of non-magnetic material, which provides a flexible, fluid-tight seal between the tubular sections. An inclined surface is formed on each spherical end to provide stability between adjacent sections and thus to provide stability for the entire conduit tip when fully bent. The diameter of the device is limited because the diameter of the tubular section with spherical ends and the tubular connector is limited by its mechanical strength.

[0005] US2016 / 0089515A1 discloses a guidewire for delivering a medical catheter to a distant target site in the body through a patient's body passage, the guidewire having a variable flexible distal portion. The distal portion facilitates the guidewire to pass through a tortuous path. The distal portion includes a sleeve portion, a flexible portion, and a core wire. The flexible portion includes a plurality of spherical members that are longitudinally displaced at the distal end of the core wire and in the covering layer. The core wire is displaced inside the sleeve, and the core wire passes through a first lumen in the sleeve and through a second lumen defined by an opening on each spherical member. The core wire is fixed to the distalmost member and has a proximal end that a doctor can manipulate to compress or stretch a plurality of members arranged in the flexible portion to control its flexibility and curvature. In addition, the member may have magnetic responsiveness to allow steering in a magnetic field. The diameter of such a device is limited because the core wire must extend over the entire length of the guide wire to be manipulated. Therefore, the reduction in the diameter of the core wire and the reduction in the pipeline itself are limited by the risk of the core wire breaking during operation.

[0006] Such devices allow for more precise navigation within the body. However, it is necessary to navigate through the sharp bends at branch junctions in body passages and through lumens that decrease in size with distance to reach target sites located farther away in the body cavity or vasculature. Summary of the invention

[0007] An object of the present invention is to provide a device for use in a mammal that can be reliably and repeatably used for diagnostic and / or interventional purposes that require high-precision navigation through sharp bends at branch junctions and smaller lumens in body passages to reach target locations, and is not limited by the above-mentioned devices.

[0008] According to the invention, this object is met by providing an arrangement having the features of claims 1 and 15. Further advantageous embodiments of the invention are subject matter of the dependent claims.

[0009] The steerable device can be a needle, guidewire, catheter, endoscope, etc. used in mammals, especially humans, for example, for inspection and / or surgery. The steerable device can be used to inspect and / or operate inside organs (e.g., liver, lungs, kidneys, brain, etc.), inside body cavities (e.g., abdomen, spinal cord, sinuses, etc.), or vascular systems. More generally, the steerable device is designed to reach the target site through sharp bends in body passages and small-sized lumens.

[0010] The steerable device includes a flexible, elongated member extending along a longitudinal axis and configured to travel within a mammalian body.

[0011] Furthermore, the steerable device comprises a flexible device tip arranged at the distal end of the elongated element. The device tip is configured to be bendable by means of an external magnetic field to allow the elongated element to be steered.

[0012] The end of the steerable device opposite the device distal end (ie, the proximal end of the steerable device) is designed to remain outside the mammal's body for external manipulation by, for example, a physician or a robot.

[0013] In particular, the elongated element terminates at a distal end in a device tip. The distal end may contain or carry a measurement and / or actuation device, such as a camera, a sensor, an ablation tip, a needle, an electrode, etc. The device may contain an inner lumen that allows fluids, needles, coils, drugs, biopsy tools, etc. to be delivered to a target site.

[0014] The device end comprises a tubular portion and a plurality of permanent magnetic elements, which are arranged in an end-to-end manner in the tubular portion, have adjacent ends with opposite polarities, and each magnetic axis is arranged along the longitudinal axis of the elongated element. This arrangement ensures that the magnetic elements attract each other in the longitudinal direction, so that the plurality of magnetic elements form a stable structure in the tubular portion. The tubular portion is arranged to extend in the longitudinal direction to the distal end of the elongated element. The tubular portion can be a pipe covering the plurality of magnetic elements, the pipe is attached to the distal end of the elongated element, or is formed as a hollow extension of the elongated element (particularly the outer wrapping layer of the elongated element) in the longitudinal direction. The tubular portion keeps the magnetic elements in the steerable device aligned in the longitudinal direction. In addition, the magnetic force acting between the magnetic elements can ensure that the plurality of magnetic elements remain axially arranged in the tubular portion in the absence of a magnetic field, or restore the axial arrangement when the magnetic field is turned off. Each magnetic element has an axial hole, which extends along its magnetic element longitudinal axis from a first axial end of the magnetic element to a second axial end of the magnetic element opposite to the first axial end, and the axial holes of the plurality of magnetic elements form an axial pipe passing through the plurality of magnetic elements. The intersection of the first axial end with the axial hole and the intersection of the second axial end with the axial hole always define a hole edge. The first axial end of the magnetic element forms a free end of the magnetic element and the second axial end of the magnetic element forms a free end of the magnetic element.

[0015] In addition, the steerable device includes a core wire that extends in the conduit through at least two of the plurality of magnetic elements. The core wire may be solid. Optionally, the core wire may also include a lumen. In this case, the core wire may be softer than a solid core wire. Under the influence of a magnetic field, the core wire may bend between the magnetic elements (i.e., at the interface between two successive magnetic elements), which allows the device tip to adapt to the curvature of the path that the steerable device must follow to move within the mammalian body.

[0016] According to the present invention, the first axial end and the second axial end have inclined surfaces to allow the magnetic element to move relative to each other and allow the device end to bend. The arrangement of the inclined surfaces allows the magnetic element to move relative to each other at the first axial end and the second axial end, which in turn can be used to control or limit the bending of the device.

[0017] In a preferred embodiment, the inclined surface is flat when viewed from the longitudinal cross section of the magnetic element, and the inclined surface forms a base angle relative to the longitudinal axis of the magnetic element, wherein the inclined surface of one axial end of a pair of adjacent ends of the successive magnetic elements and the inclined surface of the other axial end form a base angle and another base angle respectively, and are designed to allow the device end to bend at a bending angle corresponding to the sum of the base angle and the other base angle. In this embodiment, the bending angle range that can be achieved at the device end can be limited for each pair of adjacent ends of the successive magnetic elements. This allows the bending of the device end to be precisely controlled at the level of two consecutive magnetic elements. In addition, the flat inclined surface provides the necessary rigidity to avoid the steerable device from bending when reaching the target position. In fact, the flat inclined surface reduces the risk of the magnetic elements flipping over each other or the ends of the magnetic elements sliding against each other when reaching the maximum bending.

[0018] In a preferred embodiment, the first axial end and the second axial end have the same slope to allow the same bending radius between adjacent magnetic elements, thereby facilitating operation and manufacturing. The slope can be round or flat when viewed from the longitudinal section of the magnetic element.

[0019] In a preferred embodiment, the first axial end and the second axial end have different slopes to allow the bending radius between adjacent magnetic elements to gradually increase or decrease from the proximal end to the distal end. The slope can be round or flat when viewed from the longitudinal cross section of the magnetic element.

[0020] Further preferred embodiments with a flat slope are disclosed below.

[0021] In a preferred embodiment, the bevel is rounded when viewed in longitudinal cross-section of the magnetic element to facilitate bending of the distal end of the device.

[0022] Further preferred embodiments with rounded bevels are disclosed below.

[0023] Furthermore, it is also conceivable to provide an embodiment in which the magnetic element has a flat bevel at the first axial end and a rounded bevel at the second axial end.

[0024] It is also conceivable to have a first plurality of consecutive magnetic elements whose first axial end and second axial end have the same first bevel, and a second plurality of consecutive magnetic elements whose first axial end and second axial end have the same second bevel, the first bevel being different from the second bevel. This embodiment allows for sections with different bending radii, which may be useful for certain types of operations. The first bevel and the second bevel may be rounded or flat.

[0025] In a preferred embodiment, a first end of the core wire is retained at a first end of the tubular portion, while a second end of the core wire opposite to the first end of the core wire is arranged in the conduit and is free to allow multiple magnetic elements to be axially displaced relative to the core wire when the device end is bent. This arrangement allows for sharp bending of the device end because, in addition to the interaction between the magnetic elements, the core wire keeps the magnetic elements aligned when the device end is bent, while the flexibility of the device end (i.e., the curvature of the device end) can be configured by the flexibility of the core wire used in the steerable device. Therefore, one end of the core wire does not have to extend to the proximal end of the steerable device in order to be manipulated by the physician to compress or extend the arrangement of the magnetic elements in the tubular portion to control the flexibility and curvature of the device end. In addition, this arrangement supports a reduction in the diameter of the steerable device.

[0026] In a preferred embodiment, the first end of the core wire is fixed by a retaining portion and extends through the elongated element, the retaining portion being arranged in the elongated element proximal to the end of the device, while the second end of the core wire opposite to the first end of the core wire is arranged in the conduit and is free to allow the plurality of magnetic elements to be axially displaced relative to the core wire when the end of the device is bent. In the case where the first end is formed as a knot, the characteristic first end is understood to be a knot from which a small section of the core wire extends, the section of the core wire extending toward the proximal end.

[0027] It is also conceivable that the core wire extends proximally over a portion of the steerable device to the proximal end of the device tip, or all the way to the proximal end of the steerable device, wherein the core wire is secured by a retaining portion disposed proximal to the device tip in the elongated element, the retaining portion being disposed at a midpoint of the core wire, the midpoint being located between the proximal and distal ends of the core wire. This arrangement also allows for sharp bending of the device tip, since the core wire can keep the magnetic elements aligned in addition to the interaction between the magnetic elements when the device tip is bent. In addition, this arrangement can also increase the stiffness of the elongated element, since the portion of the core wire extending in the elongated element is located outside the tubular portion.

[0028] In a preferred embodiment, the plurality of magnetic elements extend over the entire axial length of the tubular portion. In other words, the tubular portion is filled with magnetic elements from a first end of the tubular portion to a second end of the tubular portion opposite the first end of the tubular portion. This embodiment allows the entire length of the tubular portion to be used to steer the steerable device.

[0029] The term "free" in relation to the core wire end means that the core wire end can move axially but its radial movement is restricted by the inner surface of the pipe.

[0030] In the present disclosure, the term "proximal end" refers to a direction or side toward an operator (eg, a physician) of the steerable device. In addition, the term "distal end" refers to a direction or side toward a patient.

[0031] In a preferred embodiment, the first end of the core wire is the proximal end of the core wire, the first end of the tubular portion is the proximal end of the tubular portion, and the second end of the core wire is the distal end of the core wire. In other words, the proximal end of the core wire forms a fixed end and is fixed to the proximal end of the tubular portion, while the distal end of the core wire forms a free end and is free in the pipe to allow multiple magnetic elements to be axially displaced relative to the core wire when the end of the device is bent. This arrangement allows the bending from the proximal end to the distal end to increase, that is, the bending radius becomes smaller from the proximal end to the distal end, because the magnetic elements arranged at the proximal end of the tubular portion are kept in place or limited in displacement, while the magnetic elements arranged at the distal end of the tubular portion can have a larger relative displacement relative to the core wire.

[0032] In a preferred embodiment, the first end of the core wire is the distal end of the core wire, the first end of the tubular portion is the distal end of the tubular portion, and the second end of the core wire is the proximal end of the core wire. In other words, the distal end of the core wire forms a fixed end and is fixed to the distal end of the tubular portion, while the proximal end of the core wire forms a free end and is free in the pipe to allow multiple magnetic elements to be axially displaced relative to the core wire when the end of the device is bent. This arrangement allows the bending from the distal end to the proximal end direction to increase, that is, the bending radius becomes smaller from the distal end to the proximal end, because the magnetic elements arranged at the distal end of the tubular portion are kept in place or limited in displacement, while the magnetic elements arranged at the proximal end of the tubular portion can have a larger relative displacement relative to the core wire.

[0033] In a preferred embodiment, the distal end of the tubular element forms the end of the steerable device to allow precise manipulation of the steerable device.

[0034] In a preferred embodiment, the length of the core wire is equal to the axial length of the plurality of magnetic elements. The length of the core wire may also include a portion of the core wire used to retain the core wire (if any).

[0035] In embodiments where the core wire is held at a first end of the tubular portion and the second end is free in a conduit formed by a plurality of magnetic elements arranged in the tubular portion, the core wire may have substantially the same length or the length may be shorter than the length of the tubular portion. In construction, the core wire is shorter than the elongated element or the steerable device. In particular, the core wire is free to extend from a proximal end extending outside the elongated element or the steerable device, thereby allowing, for example, an operator to directly manipulate the core wire.

[0036] In a non-deformed state (which may be a static state), the length of the core wire may be equal to or shorter than the axial length of the plurality of magnetic elements. In a deformed state, the free end of the core wire will shift into the magnetic element where it is located, that is, relative to the magnetic element where it is located, the free end of the core wire will shift toward the retaining end.

[0037] The number of permanent magnetic elements and their respective lengths can be selected to allow the device end to bend and best adapt to the curvature of the path that the steerable device must follow to move in the mammalian body. The selection also depends on the characteristics of the steerable device required for operation. In a preferred embodiment, the plurality of permanent magnetic elements include 3 to 100 magnetic elements. It is also possible to envision embodiments with more than 100 magnetic elements. In a more preferred embodiment, the plurality of permanent magnetic elements include 3 to 20 magnetic elements to allow optimal bending of the device end and to simplify manufacturing at the same time.

[0038] In a preferred embodiment, each magnetic element of the plurality of magnetic elements has an axial symmetry about its magnetic axis. This allows for simple control of the device end in a magnetic field.

[0039] In a preferred embodiment, the axial lengths of the magnetic elements in the plurality of magnetic elements are the same. This allows the device tip to bend uniformly in a magnetic field with a nearly continuous bending radius. The control of the steerable device is further improved.

[0040] In a preferred embodiment, the core wire is made of a plurality of strands, wherein a strand of the plurality of strands can be fixed to a first end of the core wire and is free at a second end of the core wire. Therefore, the flexibility of the core wire can be designed to have a greater degree of freedom, taking into account the physical properties of the different strands. The curvature of the device end can be configured by the flexibility of the strands selected for the core wire.

[0041] In a preferred embodiment, the strands are made of the same material to form a core wire with homogeneous properties, so that the steerable device can be easily controlled. A core wire with at least one strand made of a different material can also be provided, for example to ensure a minimum resistance to strain when the tubular portion is deformed.

[0042] The core wire made of multiple wire strands is also called a twisted core wire, and the outer diameter of the twisted core wire is defined as the diameter of a cylindrical virtual surface that covers the multiple wire strands and contacts the outermost radial surfaces of the wire strands.

[0043] In a more preferred embodiment, the core wire is made of a plurality of strands extending parallel to each other along the longitudinal axis, wherein a strand of the plurality of strands can be fixed at a first end of the core wire and free at a second end of the core wire. This arrangement allows for simple manufacture of the device tip.

[0044] In a more preferred embodiment, the core wire is made of a plurality of strands bundled along the longitudinal axis, wherein a strand of the plurality of strands can be fixed to a first end of the core wire and free at a second end of the core wire. For example, the strands can be bundled in a spiral manner and intertwined. The bundled strands have the following advantages: the core wire can be further extended and thus can exhibit additional flexibility because the strands can be slightly loosened (unfolded or untied) when the device end is bent.

[0045] In a preferred embodiment, a plurality of strands include two to seven strands. In particular, the arrangement of three strands or seven strands allows a symmetrical structure, thereby being easy to bend and control. Preferably, three strands are used to reduce the diameter of the core wire. The number of strands can also be used as a parameter for adjusting the flexibility of the core wire.

[0046] In a preferred embodiment, the lengths of the strands in the plurality of strands are different. The resulting effect is that the flexibility of the core wire is different along the longitudinal direction, so that the available bending radius is also different along the longitudinal direction. A certain part of the core wire has the lowest flexibility, and the cross section of this part includes all the strands of the plurality of strands, usually located at the first end or in the region of the first end, wherein the plurality of strands are fixed. In another part of the core wire, its cross section lacks at least one strand, i.e., when this other part is located at the far end of the shortest strand among the plurality of strands, its flexibility will increase.

[0047] In the embodiment where the core wire is made of a plurality of strands, each strand has a free end. The length of the core wire is defined as the length of the longest strand. The end of the core wire is defined as the end of the longest strand.

[0048] In a preferred embodiment, the length of the plurality of strands is a multiple of the length of the magnetic element. Preferably, at least one strand extends over the entire axial length of the plurality of magnetic elements. The at least one strand extending over the entire axial length keeps the magnetic elements aligned when the device ends are bent. In this embodiment, during deformation to a deformed state, for example under the action of a magnetic field, each strand in the non-deformed state will always move into the magnetic element in which it is located in a direction leading to the fixed end, relative to the magnetic element, and will not move from one magnetic element to an adjacent magnetic element. Therefore, during deformation, the flexibility remains constant at the interface between two consecutive magnetic elements. Jumps in flexibility during deformation can be avoided, as this occurs each time a strand is displaced from a magnetic element to an adjacent magnetic element. The control of the steerable device is improved.

[0049] In a preferred embodiment, the outer diameter of the core wire is substantially the same as the inner diameter of the pipe to maintain the alignment of the magnetic elements in the longitudinal direction.

[0050] The term "substantially the same" means that the outer diameter of the core wire is the same within manufacturing tolerances, such that the tolerances allow for displacement of the core wire within the pipe. In particular, the friction between the core wire and the magnetic element must be kept low to ensure that in the absence of a magnetic field, the tip of the device can rebound to a non-deformed state without slight deformation.

[0051] In a preferred embodiment, the outer diameter of the core wire at its first end is preferably substantially the same as the inner diameter of the tube and decreases in the direction toward the second end. In this embodiment, the flexibility of the device tip increases from the proximal end to the distal end to allow sharp bends.

[0052] In a preferred embodiment, the steerable device includes a retaining portion arranged at the first end of the tubular portion to retain the first end of the core wire at the first end of the tubular portion. The retaining portion can be a part of the tubular portion that is configured to retain the first end of the core wire at the first end of the tubular portion. In a preferred embodiment, the retaining portion and the tubular portion are formed as one body to reduce production and assembly costs.

[0053] In a preferred embodiment, the steerable device comprises a holding portion arranged at the first end of the tubular portion, preferably arranged in the tubular portion, the holding portion having a channel extending axially through the holding portion from a side facing away from the second end of the tubular portion to a side of the holding portion facing the second end of the tubular portion. The channel allows the core wire to be inserted to hold the first end of the core wire on the side facing away from the second end of the tubular portion.

[0054] In a preferred embodiment, the steerable device comprises a retaining portion arranged at the first end of the tubular portion, preferably arranged in the tubular portion, the retaining portion having a cavity on its side facing away from the second end of the tubular portion, and having a channel extending axially from the cavity through the retaining portion to the side of the retaining portion facing the second end of the tubular portion. When the core wire is retained in the cavity, the cavity allows the first end of the core wire to be protected and the movement of the first end of the core wire to be limited.

[0055] In a preferred embodiment, the first end of the core wire has a thickened portion (preferably in the form of a bead), wherein the channel is designed to axially maintain the thickened portion on the side facing away from the second end of the tubular portion when the core wire is inserted into the channel. The advantage of this embodiment is that the first end of the core wire is maintained in a position along the longitudinal axis in a manner that is easy to assemble.

[0056] In a preferred embodiment, the steerable device includes a retaining portion arranged at the first end of the tubular portion, preferably arranged in the tubular portion, the retaining portion having a cavity on a side thereof facing away from the second end of the tubular portion, and having a channel extending axially from the cavity through the retaining portion to the side of the retaining portion facing the second end of the tubular portion. In addition, the first end of the core wire has a thickened portion (preferably in the shape of a ball), wherein the cavity is designed to receive the thickened portion, and the channel is designed to axially retain the thickened portion in the cavity when the core wire is inserted into the channel. The advantage of this embodiment is that the first end of the core wire is maintained in a position along the longitudinal axis, which allows the first end of the core wire to move in the axial direction, but this movement is limited by the cavity in which the core wire is accommodated.

[0057] In a preferred embodiment, wherein the core wire is made of a plurality of strands, each strand may have a first end with a thickened portion (preferably in the shape of a bead), wherein the channel is designed to axially retain the plurality of thickened portions when the core wire is inserted into the channel.

[0058] In a preferred embodiment, wherein the core wire is made of a plurality of wire strands, each wire strand may have a first end having a thickened portion (preferably in the shape of a bead), wherein the cavity is designed to receive the plurality of thickened portions, and the channel is designed to axially retain the plurality of thickened portions in the cavity when the core wire is inserted into the channel.

[0059] In a preferred embodiment, the first end of the core wire is the proximal end of the core wire, the first end of the tubular portion is the proximal end of the tubular portion, and the second end of the core wire is the distal end of the core wire, and the steerable device includes a retaining portion in the form of a connector. The connector is at least partially inserted into the elongated element at the distal end of the elongated element (preferably inserted in a non-detachable manner), the connector is arranged at the proximal end of the tubular portion, and in its inserted position, defines a cavity on the side facing the elongated element. In addition, the connector has an opening extending axially from the cavity to the tubular portion. In addition, the proximal end of the core wire has a thickened portion (preferably in the shape of a ball), wherein the cavity is designed to receive the thickened portion, and the opening is designed to axially retain the thickened portion in the cavity when the core wire is inserted into the channel. Any other form of thickened portion may also be used, such as a thickened portion in the form of a knot or a curled edge, as long as it is designed to axially retain the core wire.

[0060] In a preferred embodiment, the steerable device comprises a retaining portion arranged at the first end of the tubular portion, preferably arranged in the tubular portion, to which the core wire is glued or fused. In both embodiments, the core wire is retained in a fixed manner that is easy to manufacture and less expensive.

[0061] In a preferred embodiment, each magnetic element is composed of two magnetic parts, which are symmetrical to each other about a symmetry plane that cuts the magnetic axis perpendicularly at the midpoint of the magnetic element from a longitudinal direction, and the two magnetic parts are arranged in an end-to-end manner and have adjacent ends with opposite polarities. In other words, each magnetic element is composed of a first magnetic part and a second magnetic part, which have flat ends extending in a symmetry plane perpendicular to the magnetic axis, wherein the flat ends of the first magnetic part and the second magnetic part are arranged adjacent to each other to form a magnetic element. The free end of the first magnetic part and the free end of the second magnetic part opposite to the respective flat ends may have an inclined surface, or have a shape suitable for the relative movement of the magnetic elements to each other. Since the flat end can be used as a reference surface to manufacture the free end of the magnetic part (especially when the free end has an inclined surface), this embodiment is easy to manufacture.

[0062] In a preferred embodiment, the closest one of the multiple magnetic elements consists of a single magnetic portion having a flat end facing the slender element to provide a simple design interface between the slender element and the end of the device and ensure that the movement of the slender element can be reliably transmitted to the end of the device.

[0063] In a preferred embodiment, the first axial ends of the plurality of magnetic elements and the second axial ends of the plurality of magnetic elements each have a slope to form a convex first axial end and a convex second axial end, thereby allowing the magnetic elements to move relative to each other.

[0064] In a preferred embodiment, the chamfer has a chamfer edge that always starts at a radial distance from the hole edge of the axial hole. This embodiment ensures that the interface between two consecutive magnetic elements has a contact surface that allows a distribution of contact forces, thereby minimizing mechanical strains that could lead to damage to the interface between two consecutive magnetic elements.

[0065] In a preferred embodiment, the inclined surface is flat when viewed in a longitudinal cross section of the magnetic element and forms a base angle relative to the longitudinal axis of the magnetic element, wherein the inclined surfaces of a first pair of adjacent ends of consecutive magnetic elements have the same first base angle, the inclined surfaces of a second pair of adjacent ends of consecutive magnetic elements have the same second base angle, and the first base angle is different from the second base angle. When viewed in a longitudinal cross section of the magnetic element, the flat inclined surface is formed so that the profile of the inclined surface follows a straight line, and the base angle is defined as the acute angle formed between the straight line and the longitudinal axis of the magnetic element. This configuration allows the device end to have different bending radii along the longitudinal axis.

[0066] In a more preferred embodiment, the first pair of adjacent ends are arranged proximal to the second pair of adjacent ends, and the first base angle is smaller than the second base angle. This configuration allows the bending angle between the first pair of adjacent ends to be smaller than the bending angle between the second pair of adjacent ends, that is, the bending radius of the device end at the interface between the first pair of adjacent ends is smaller than the bending radius at the interface between the second pair of adjacent ends, that is, the bending radius of the device end increases from the proximal end to the distal end.

[0067] In a more preferred embodiment, the plurality of base angles are in the range of 30° to 88°. This range of angles allows the device tip to deform in a series of segments - each segment corresponding to a magnetic element - with angles of 60° to 176° relative to one another. This range allows the bending radius of the device tip to be adapted to accommodate the curvature of most paths that a steerable device must follow to move within a mammal.

[0068] In a more preferred embodiment, the plurality of base angles have the same value within the range of 45° to 80°.Simulations have shown an optimal bending radius depending on the curvature of the path that the steerable device must follow to move within the mammalian body.

[0069] In a preferred embodiment, the slope is circular when viewed in longitudinal cross-section of the magnetic element, wherein the slopes of a first pair of adjacent ends of the magnetic element have the same first radius of curvature, and the slopes of a second pair of adjacent ends of the magnetic element have the same second radius of curvature, and the first radius of curvature is different from the second radius of curvature. The circular slope is convex (i.e., curved outwardly relative to the magnetic element) and has a curved profile. This configuration allows the device end to have different curvature radii along the longitudinal axis.

[0070] In a preferred embodiment, the circular bevel is in the shape of a circular arc or an elliptical arc. Therefore, the end of the magnetic element is spherical, or the end of the magnetic element is elliptical and forms a part of an ellipsoid.

[0071] In a more preferred embodiment, the first pair of adjacent ends are arranged proximal to the second pair of adjacent ends, and the first radius of curvature is smaller than the second radius of curvature. This configuration allows the bending angle between the first pair of adjacent ends to be greater than the bending angle between the second pair of adjacent ends, that is, the bending radius of the device end at the interface between the first pair of adjacent ends is smaller than the bending radius at the interface between the second pair of adjacent ends, that is, the bending radius of the device end increases from the proximal end to the distal end.

[0072] Rounded and flat sections may be combined to optimize the shape of the ramp and thus the bending ability of the steerable device.

[0073] The present invention also discloses a steerable device for use in a mammal, comprising a flexible elongated element extending along a longitudinal axis and configured to travel in the mammal. In addition, the steerable device comprises a flexible device end, which is arranged at the distal end of the elongated element and is configured to allow the elongated element to be steered by means of an external magnetic field. In addition, the device end comprises a tubular portion and a plurality of permanent magnetic elements, which are arranged in an end-to-end manner in the tubular portion, have adjacent ends with opposite polarities, and have respective magnetic axes arranged along the longitudinal axis, wherein each magnetic element has an axial hole extending along its magnetic element longitudinal axis from a first axial end of the magnetic element to a second axial end of the magnetic element opposite to the first axial end, and the axial holes of the plurality of magnetic elements form an axial conduit through the plurality of magnetic elements. The steerable device also comprises a core wire, which extends through the plurality of magnetic elements in the conduit.

[0074] In a preferred embodiment, a first end of the core wire is retained at the first end of the tubular portion, and a second end of the core wire opposite the first end is retained at the second end of the tubular portion, wherein the core wire is designed to allow multiple magnetic elements to be axially displaced relative to the core wire when the end is bent. This arrangement allows for sharp bending of the device end because the core wire maintains the alignment of the magnetic elements when the device end is bent, while the flexibility of the device end (i.e., the curvature of the device end) can be configured by the core wire used in the steerable device. Therefore, one end of the core wire does not have to extend to the proximal end of the steerable device in order to be manipulated by the physician to compress or extend the arrangement of the magnetic elements in the tubular portion to control the flexibility and curvature of the device end.

[0075] In a preferred embodiment, the steerable device includes a retaining portion arranged at a first end of the tubular portion to retain the first end of the core wire at the first end of the tubular portion, and another retaining portion arranged at a second end of the tubular portion to retain the second end of the core wire at the second end of the tubular portion. The retaining portion and the another retaining portion can be a portion of the tubular portion that is configured to retain the first end of the core wire at the first end of the tubular portion and retain the second end of the core wire at the second end of the tubular portion.

[0076] In a preferred embodiment, the retaining portion, the further retaining portion and the tubular portion are formed in one piece to reduce production and assembly costs.

[0077] In a preferred embodiment, the first end of the core wire is retained at the proximal end of the device end in the slender element (preferably by a retaining portion disposed in the slender element) and extends through the slender element, and the second end of the core wire opposite to the first end of the core wire is retained at the second end of the tubular portion (preferably by another retaining portion) at an adjacent end.

[0078] In a preferred embodiment, the core wire is designed so that the core wire is elastically deformable when the end is bent to allow multiple magnetic elements to be axially displaced relative to the core wire, wherein the first end of the core wire and the second end of the core wire are held in a fixed manner. In this embodiment, the flexibility of the device end (i.e., the curvature of the device end) can be configured by means of the elasticity of the core wire used in the steerable device, that is, by the length difference between the core wire in a deformed state and the multiple magnetic elements. The core wire deforms in an elastic manner, and the length of the core wire in the longitudinal direction is extended under the influence of the force applied to bend the device end. When the force is removed, the core wire returns to its original length and shape. The core wire is designed so that it is elastically deformable in the longitudinal direction.

[0079] In a preferred embodiment, the core wire is designed so that the length of the core wire is greater than the axial length of the plurality of magnetic elements, wherein the first end of the core wire and / or the second end of the core wire maintains a clearance designed to allow the plurality of magnetic elements to be axially displaced relative to the core wire when the tip is bent. In this embodiment, the flexibility of the device tip (i.e., the curvature of the device tip) can be configured by the length difference between the core wire and the plurality of magnetic elements.

[0080] In a preferred embodiment, the first end of the core wire is retained at the proximal end of the device end in the slender element (preferably by a retaining portion disposed in the slender element) and extends through the slender element, and the second end of the core wire opposite to the first end of the core wire is retained at the second end of the tubular portion (preferably by another retaining portion) at an adjacent end.

[0081] In a preferred embodiment, the difference in length between the core wire and the plurality of magnetic elements is about 2% to 10% to allow for longitudinal displacement of the core wire. This embodiment allows the device tip to bend sharply at a branch junction in a body passage.

[0082] In addition to the features specifically related to the free end of the core wire disclosed with respect to the first aspect of the present invention, the preferred features of the steerable device associated with the above-mentioned embodiments also apply to these embodiments with the same advantages and effects, wherein the first end of the core wire in the above-mentioned embodiments is fixed to the first end of the tubular part, and the second end of the core wire opposite to the first end of the core wire is arranged in the pipe and is free, while the first end of the core wire in these applicable embodiments is fixed to the first end of the tubular part, and the second end of the core wire opposite to the first end is fixed to the second end of the tubular part without play or with play.

[0083] In particular, for embodiments in which a first end of the core wire is fixed at a first end of the tubular portion and a second end of the core wire opposite to the first end is held at the second end of the tubular portion with or without play, the steerable device may include a retaining portion arranged at the first end of the tubular portion to retain the first end of the core wire at the first end of the tubular portion and another retaining portion arranged at the second end of the tubular portion to retain the second end of the core wire at the second end of the tubular portion.

[0084] In a preferred embodiment, the steerable device comprises a retaining portion arranged at the first end of the tubular portion, preferably in the tubular portion, and another retaining portion arranged at the second end of the tubular portion, preferably in the tubular portion. The retaining portion has a channel that extends axially from the side facing away from the second end of the tubular portion through the retaining portion to the side of the retaining portion facing the second end of the tubular portion. The other retaining portion has another channel that extends axially from the side facing away from the first end of the tubular portion through the other retaining portion to the side of the other retaining portion facing the first end of the tubular portion. The channel and the other channel allow the core wire to be inserted to respectively retain the first end of the core wire on the side facing away from the second end of the tubular portion and retain the second end of the core wire on the side facing away from the first end of the tubular portion.

[0085] In a preferred embodiment, the retaining portion has a cavity on its side facing away from the second end of the tubular portion, and a passage extends axially from the cavity through the retaining portion, and the other retaining portion has a cavity on its side facing away from the first end of the tubular portion, and another passage extends axially from the cavity through the retaining portion. When the first and second ends of the core wire are retained in their respective cavities, the cavities can protect the first and second ends of the core wire and limit the movement of the first and second ends of the core wire.

[0086] In a preferred embodiment, the first end of the core wire has a thickened portion (preferably in the shape of a ball), wherein the channel is designed to axially maintain the thickened portion on the side opposite to the second end of the tubular portion when the core wire is inserted into the channel. Any other form of thickened portion may also be used, such as a thickened portion in the form of a knot or a curled edge, as long as it is designed to axially maintain the core wire. In addition, the second end of the core wire has a thickened portion (preferably in the shape of a ball), wherein another channel is designed to axially maintain the thickened portion on the side opposite to the first end of the tubular portion when the core wire is inserted into another channel. The advantage of this embodiment is that the first end and the second end of the core wire are maintained in a position along the longitudinal axis in a manner that is easy to assemble. In addition, when the core wire is maintained, the cavity axially limits the movement of the core wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] Figure 1 shows a schematic perspective view of a distal portion of a steerable device according to a first embodiment of the present invention;

[0088] Figure 2 shows a schematic longitudinal cross-section of a device tip of a steerable device according to a second embodiment of the invention;

[0089] Figure 3 Shows Figure 2 A detailed schematic cross section of the region marked with B in the embodiment of FIG.

[0090] Figure 4 Shows Figure 2 A detailed schematic cross section of the region marked with C in the embodiment of FIG.

[0091] Figure 5 Shows Figure 2 A detailed schematic cross section of the region marked D in the embodiment of FIG.

[0092] Figure 6 shows a schematic side view of a device end of a steerable device according to a third embodiment of the invention;

[0093] Figure 7 Shows Figure 6 A schematic side view of the areas marked 1, 2 and 3 in an embodiment of the present invention;

[0094] Figure 8 a schematic longitudinal cross-section showing a device tip of a steerable device according to a fourth embodiment of the invention; and

[0095] Fig. 9 A schematic longitudinal cross-section of a device tip of a steerable device according to a fifth embodiment of the invention is shown. DETAILED DESCRIPTION

[0096] A first embodiment of the steerable device 10 according to the present invention is configured as follows Figure 1 The catheter is shown.

[0097] The steerable device 10 has a structure that is at least approximately rotationally symmetrical with respect to its longitudinal axis, having a narrow circular cross section that is proportional to its length. The steerable device 10 comprises a flexible, elongated element 12 in the form of an elongated shaft, the longitudinal axis of the elongated element 12 corresponding to the longitudinal axis L of the steerable device 10, the elongated element 12 having a circular cross section and extending over the length of the steerable device 10. The steerable device 10 has Figure 1 The proximal end not shown in the figure and the distal end 14 located on the surgical site side.

[0098] In addition, the steerable device 10 includes a flexible device tip 20 arranged at the distal end 16 of the elongated element 12. The device tip 20 is configured to bend with the aid of an external magnetic field to allow the elongated element to be steered. In particular, the elongated element 12 terminates at the distal end of the device tip 20. The device tip 20 bends in a deformed state under the action of the magnetic field.

[0099] exist Figure 2 as well as Figure 3 , Figure 4 and Figure 5 In the second embodiment of the steerable device in the non-deformed state shown, more particularly, the device tip 20 includes a tubular portion 22 and a plurality of permanent magnetic elements 30 arranged in an end-to-end manner in the tubular portion 22, having adjacent ends of opposite polarity and with respective magnetic axes arranged along the longitudinal axis L of the elongated element. Figure 2 In the disclosed embodiment, there are five magnetic elements 30. The magnetic elements 30 attract each other in the longitudinal direction L, so that the plurality of magnetic elements 30 form a stable structure in the tubular portion 22.

[0100] The tubular portion 22 is formed as a tube surrounding the plurality of magnetic elements 30 and extends distally from the elongated element 12 in the longitudinal direction, while being flush with the outer sheath 32 of the elongated element. The tubular portion 22 and the magnetic force acting between the magnetic elements keep the magnetic elements 30 aligned in the longitudinal direction L in the steerable device 10.

[0101] Each magnetic element 30 has an axial hole 40 extending along its magnetic element longitudinal axis from a first axial end of the magnetic element to a second axial end of the magnetic element opposite to the first axial end. The axial holes 40 of the plurality of magnetic elements form an axial conduit 46 that passes through the plurality of magnetic elements. The intersection of the first axial end with the axial hole and the intersection of the second axial end with the axial hole always define a hole edge 48. Each magnetic element of the plurality of magnetic elements has an axial symmetry about its magnetic axis.

[0102] In addition, the steerable device 10 includes a core wire 50 that extends in the conduit 46 through at least two of the plurality of magnetic elements 30. Under the influence of the magnetic field, the core wire 50 can bend between the magnetic elements (i.e., at the interface between two consecutive magnetic elements), which allows the device tip 20 to adapt to the curvature of the path that the steerable device 10 must follow to move within the mammalian body.

[0103] exist Figure 2In the disclosed embodiment, a first end of the core wire is retained at a first end of the tubular portion 22, and a second end of the core wire opposite the first end is disposed in the conduit 46. The second end is free to allow the plurality of magnetic elements 50 to be axially displaced relative to the core wire 50 when the device tip 20 is bent. Embodiments are also contemplated in which the first end of the core wire is fixed in an elongated element proximal to the tubular portion.

[0104] The tubular portion 22 is filled with magnetic elements 50 from the first end of the tubular portion to the second end of the tubular portion opposite to the first end of the tubular portion (i.e., over its entire axial length). In the embodiment shown, the tubular portion contains four magnetic elements 50, and the magnetic portion proximal to the four magnetic elements has a half form of the magnetic element 50.

[0105] Currently, the first end of the core wire 50 is the proximal end 52 of the core wire, the first end of the tubular portion is the proximal end 53 of the tubular portion, the second end of the core wire is the distal end 54 of the core wire, and the second end of the tubular portion is the distal end 55 of the tubular portion.

[0106] The core wire 50 is made of multiple strands, wherein the strands 60a, 60b, 60c of the multiple strands can be retained at the first end of the core wire (i.e., the proximal end 52 of the core wire in this embodiment) and are free at the second end of the core wire (i.e., the distal end 54 of the core wire in this embodiment).

[0107] exist Figure 2 In the embodiment, the core wire has three strands 60. The strands 60a, 60b, and 60c in the plurality of strands have different lengths. Figure 2 In the embodiment of the core wire 50 having three strands, the first strand 60a extends to the second magnetic element, the second strand 60b extends to the second magnetic element, and the third strand 60c (the longest strand) extends over 100% of the length of the plurality of magnetic elements, here to the fourth magnetic element. The resulting effect is that the flexibility of the core wire is different in the longitudinal direction, so that after 50%, 75% and 100% of the core wire length, the achievable bending radius is also different in the longitudinal direction.

[0108] In the first part of the core wire, the flexibility is the lowest, that is, the bending radius is the largest, and the first part includes all the wire strands in the plurality of wire strands (in Figure 2 The first part extends from the proximal end 52 of the core wire 50 to the end of the first strand 60a, wherein a plurality of strands 60a, 60b, 60c are retained. The flexibility of the second part of the core wire 50 increases, and the second part extends distally to the first part until the end of the second strand 60b including only two strands. The flexibility of the third part of the core wire 50 further increases, and the third part extends distally to the second part until the end of the third strand 60c and only one strand remains. Figure 4The transition from the first part to the second part is shown. Figure 5 The transition from the second section to the third section is shown.

[0109] like Figure 2 and Figure 3 As shown, the steerable device 10 includes a holding portion 70, which is arranged in a non-detachable manner at the first end of the tubular portion 22 (here, the proximal end 53 of the tubular portion, which is located in the tubular portion). The holding portion 70 has a cavity 71 on its side facing away from the second end of the tubular portion (i.e., the side facing away from the distal end 55 of the tubular portion), and has a channel 74, which extends axially from the cavity 71 through the holding portion 70 to the side of the holding portion facing the second end 55 of the tubular portion.

[0110] In addition, the first end of the core wire has a thickened portion 76 in the form of a plurality of balls 76a, 76b, each ball being formed at the first end (here, the proximal end) of a strand in the plurality of strands. The cavity 71 is designed to receive the thickened portion 76, and the channel 74 is designed to hold the thickened portion axially in the cavity when the core wire is inserted into the channel.

[0111] Each magnetic element 30 of the plurality of magnetic elements is composed of two magnetic portions 72a and 72b, which are symmetrical to each other about a symmetry plane that perpendicularly cuts the magnetic axis at the midpoint of the magnetic element when viewed in the longitudinal direction. The magnetic portions are arranged end to end and have adjacent ends with opposite polarities. In other words, each magnetic element is composed of a first magnetic portion 72a and a second magnetic portion 72b, each of which has a flat end extending in the symmetry plane, wherein the flat end 74a of the first magnetic portion 72a and the flat end 74b of the second magnetic portion 72b are arranged adjacent to each other to form the magnetic element 30.

[0112] like Figure 2 As shown, the most proximal magnetic element of the plurality of magnetic elements is made of a single magnetic portion having a flat end facing the elongated element to provide a simple interface between the elongated element and the device tip.

[0113] The free end 78a of the first magnetic part and the free end 78b of the second magnetic part have a bevel 79 relative to their respective flat ends to allow the magnetic elements 30 to move relative to each other. In this embodiment, the bevel 79 is always circular when viewed in a longitudinal cross section of the magnetic element, wherein the bevel has the same radius of curvature for all magnetic elements in the plurality of magnetic elements. This configuration allows for the cost-effective manufacture of the steerable device.

[0114] Figure 6The device end of the steerable device according to the third embodiment disclosed in is shown in a side view, wherein the tubular portion, i.e., the tube enclosing the plurality of magnetic elements, is not included. Figure 2 The second embodiment disclosed in is substantially the same as that disclosed in the prior art except for the inclined arrangement of the free end of the magnetic element.

[0115] The inclined surfaces 79 of the free ends of the magnetic elements in the third embodiment are flat and form a base angle α relative to the longitudinal axis L of their respective magnetic elements. At present, from the proximal end to the distal end, the inclined surfaces 79 of the first pair 80 of adjacent free ends of the magnetic elements have the same first base angle α1, the inclined surfaces 79 of the second pair 82 of adjacent free ends of the magnetic elements have the same second base angle α2, and the inclined surfaces 79 of the third pair 84 of adjacent free ends of the magnetic elements have the same third base angle α3, wherein α1>α2>α3, that is, from one pair of adjacent free ends to the next pair of adjacent free ends, the base angle increases gradually from the proximal end to the distal end.

[0116] and Figure 6 The base angles α1, α2 and α3 corresponding to the pairs of adjacent free ends of the magnetic element shown are defined as follows: Figure 7 It is schematically shown in FIG.

[0117] Due to this arrangement, the bending radius gradually decreases from the proximal end to the distal end, and the device tip can bend more sharply from the proximal end to the distal end.

[0118] Figure 8 A fourth embodiment of a steerable device is disclosed, in which only a portion of the elongated element 12 and the arrangement of the plurality of magnetic elements are shown without a tubular portion, i.e., without a tube enclosing the plurality of magnetic elements. The first end of the core wire is held in a fixed manner in a holding portion 70 at the first end of the tubular portion, and the second end of the core wire opposite to the first end is arranged in the conduit 46. The second end is free to allow the plurality of magnetic elements 50 to be axially displaced relative to the core wire 50 when the device tip 20 is bent.

[0119] Currently, the first end of the core wire is the distal end 54 of the core wire 50 and the first end of the tubular portion is Figure 8 The second end of the core wire 50 is the proximal end 52 of the core wire.

[0120] exist Figure 8 In the embodiment, the core wire is solid and does not have multiple strands.

[0121] The holding portion 70 has a cavity 71 on its side facing away from the proximal end of the tubular portion, and has a channel 74, which extends axially from the cavity 71 through the holding portion 70 to the side of the holding portion facing the proximal end of the tubular portion. In addition, the distal end 54 of the core wire has a bead-shaped thickened portion 76. The cavity 71 is designed to receive the thickened portion 76, and the channel 74 is designed to axially retain the thickened portion in the cavity when the core wire is inserted into the channel.

[0122] Fig. 9 A fifth embodiment of a steerable device is disclosed, wherein only a portion of the elongated element 12 and the arrangement of the plurality of magnetic elements is shown without the tubular portion, ie without the tube enclosing the plurality of magnetic elements.

[0123] In this embodiment, the arrangement of the first end of the core wire 50 (ie, the distal end 54 of the core wire) and the first end of the tubular portion (ie, the distal end) is similar to that of the fourth embodiment.

[0124] The fifth embodiment differs from the fourth embodiment mainly in that the second end 52 of the core wire opposite to the first end 54 is fixed in a fixed manner in another retaining portion 70a at the second end of the tubular portion, and the second end 52 is not free. For this purpose, the second end 52 of the core wire has another thickened portion 76a in the shape of a bead. In addition, the core wire 50 is elastically deformable to allow the plurality of magnetic elements 30 to be axially displaced relative to the core wire 50 when the end of the device is bent.

[0125] The arrangement of the other retaining portion 70a is similar to the retaining portion 70 in the fourth embodiment, and the other retaining portion 70a has another cavity 71a and another channel 74a, wherein the other cavity 71a is designed to receive another thickened portion 76a, and the other channel 74a is designed to axially retain the thickened portion in the cavity when the core wire is inserted into the channel.

[0126] List of reference numerals

[0127] Steerable device 10

[0128] Elongated element 12

[0129] The distal end 14 of the steerable device

[0130] The distal end 16 of the elongated member

[0131] Device end 20

[0132] Tubular portion 22

[0133] Magnetic element 30

[0134] The outer covering 32 of the elongated element

[0135] Axial hole 40

[0136] Pipeline 46

[0137] Hole edge 48

[0138] Core wire 50

[0139] The proximal end 52 of the core wire

[0140] The proximal end 53 of the tubular portion

[0141] The distal end 54 of the core wire

[0142] The distal end 55 of the tubular portion

[0143] Core wire strands 60a, 60b, 60c

[0144] Keep part 70

[0145] Cavity 71

[0146] The first magnetic portion and the second magnetic portion 72a, 72b

[0147] The flat end 74a of the first magnetic portion

[0148] The flat end 74b of the second magnetic portion

[0149] Thickened part 76

[0150] Balls 76a, 76b

[0151] The free end 78a of the first magnetic portion

[0152] The free end 78b of the second magnetic portion

[0153] Incline 79

[0154] Base angles α, α1, α2, α3

[0155] The longitudinal axis L of the elongated element

[0156] The first pair, the second pair, and the third pair of adjacent free ends 80, 82, 84

Claims

1. A steerable device (10) for use in a mammal, comprising: - a flexible, elongated element (12) extending along a longitudinal axis (L) and configured to pass within a mammalian body; a flexible device tip (20) arranged at the distal end (16) of the elongated element (12) and configured to allow the elongated element (12) to be steered by means of an external magnetic field, the device tip (20) comprising a tubular portion (22) and a plurality of permanent magnetic elements (30) arranged in an end-to-end manner in the tubular portion (22) with adjacent ends of opposite polarity and with their respective magnetic axes arranged along the longitudinal axis (L); Each magnetic element (30) has an axial hole (40), the axial hole (40) extending along the longitudinal axis of the magnetic element from a first axial end of the magnetic element to a second axial end of the magnetic element opposite to the first axial end, and the axial holes (40) of the plurality of magnetic elements (30) form an axial conduit (46) passing through the plurality of magnetic elements; a core wire (50) extending in the conduit (46) through at least two magnetic elements (30) of the plurality of magnetic elements; Characterized in that the first axial end and the second axial end have beveled surfaces (79) to allow the magnetic elements (30) to move relative to each other and to allow the device tip (20) to bend.

2. The steerable device (10) according to claim 1, characterized in that The inclined surface (79) is flat when viewed from the longitudinal cross-section of the magnetic element, and the inclined surface (79) forms a bottom angle relative to the longitudinal axis of the magnetic element, wherein the inclined surface (79) at one axial end and the inclined surface at the other axial end of a pair of adjacent ends (80) of consecutive magnetic elements respectively form a bottom angle and another bottom angle, and are designed to allow the end (20) of the device to bend at a bending angle corresponding to the sum of the bottom angle and the other bottom angle.

3. The steerable device (10) according to claim 2, characterized in that: The inclined surfaces (79) of a first pair of adjacent ends (80) of consecutive magnetic elements have a same first base angle (α1), the inclined surfaces (79) of a second pair of adjacent ends (82) of consecutive magnetic elements have a same second base angle (α2), and the first base angle (α1) is different from the second base angle (α2).

4. The steerable device (10) according to claim 3, characterized in that The first pair of adjacent ends (80) is arranged proximal to the second pair of adjacent ends (82), and the first base angle (α1) is greater than the second base angle (α2).

5. The steerable device (10) according to claim 1, characterized in that: The bevel (79) is rounded when viewed in longitudinal cross-section of the magnetic element to allow bending of the device tip (20).

6. The steerable device (10) according to claim 5, characterized in that The inclined surfaces (79) of the first pair of adjacent ends (80) of the magnetic element have the same first curvature radius, and the inclined surfaces (79) of the second pair of adjacent ends (82) of the magnetic element have the same second curvature radius, and the first curvature radius is different from the second curvature radius.

7. The steerable device (10) according to any one of claims 1 to 6, characterized in that The magnetic elements (30) have the same axial length.

8. A steerable device (10) according to any one of claims 1 to 7, characterised in that A first end of the core wire (50) is retained at a first end of the tubular portion (22), and a second end of the core wire opposite to the first end is disposed in the conduit (46) and is free to allow axial displacement of the plurality of magnetic elements relative to the core wire (50) when the device tip (20) is bent.

9. The steerable device (10) according to claim 8, characterized in that The first end of the core wire (50) is the proximal end (52) of the core wire, the first end of the tubular portion (22) is the proximal end (53) of the tubular portion, and the second end of the core wire (50) is the distal end (54) of the core wire.

10. The steerable device (10) according to claim 8, characterized in that The first end of the core wire (50) is the distal end (54) of the core wire, the first end of the tubular portion (22) is the distal end (55) of the tubular portion, and the second end of the core wire (50) is the proximal end (52) of the core wire.

11. The steerable device (10) according to any one of claims 8 to 10, characterized in that The core wire (50) is made of a plurality of wire strands (60a, 60b, 60c) extending parallel to each other along a longitudinal axis (L), or is made of a plurality of wire strands bundled along the longitudinal axis (L).

12. The steerable device (10) according to claim 11, characterized in that The plurality of wire strands (60a, 60b, 60c) each have a length corresponding to a multiple of the length of the magnetic element (30).

13. The steerable device (10) according to any one of claims 8 to 12, characterized in that The tubular portion (22) comprises a retaining portion (70) arranged at a first end of the tubular portion (22), the retaining portion (70) being designed to retain the first end of the core wire at the first end of the tubular portion.

14. The steerable device (10) according to claim 13, characterized in that The retaining portion (70) has a cavity (71) on the side thereof facing away from the second end of the tubular portion, and has a channel extending axially from the cavity (71) through the retaining portion (70) to the side of the retaining portion facing the second end of the tubular portion, and the first end of the core wire (50) has a thickened portion (76), and the thickened portion (76) is preferably in the shape of a bead, wherein the cavity (71) is designed to receive the thickened portion (76), and the channel is designed to axially retain the thickened portion (76) in the cavity (71) when the core wire is inserted into the channel.

15. The steerable device (10) according to any one of claims 13 to 14, characterized in that The core wire (50) is glued to the retaining portion (70) or fused to the retaining portion.

16. The steerable device (10) according to any one of claims 1 to 15, characterized in that Each magnetic element (30) among the plurality of magnetic elements is composed of two magnetic parts (72a, 72b), the two magnetic parts (72a, 72b) are symmetrical to each other about a symmetry plane perpendicularly cutting the magnetic axis at the midpoint of the magnetic element (30) as viewed from the longitudinal direction, and the two magnetic parts (72a, 72b) are arranged in an end-to-end manner and have adjacent ends with opposite polarities.

17. A steerable device (10) for use in a mammal, comprising: - a flexible, elongated element (12) extending along a longitudinal axis (L) and configured to pass within a mammalian body; a flexible device tip (20) arranged at the distal end of the elongated element (12) and configured to allow the elongated element (12) to be steered by means of an external magnetic field, the device tip (20) comprising a tubular portion (22) and a plurality of permanent magnetic elements (30) arranged in an end-to-end manner in the tubular portion (22) with adjacent ends of opposite polarity and with their respective magnetic axes arranged along the longitudinal axis (L); Each magnetic element (30) has an axial hole (40), the axial hole (40) extending along the longitudinal axis of the magnetic element from a first axial end of the magnetic element to a second axial end of the magnetic element opposite to the first axial end, and the axial holes (40) of the plurality of magnetic elements form an axial conduit (46) passing through the plurality of magnetic elements (30); - a core wire (50) extending in the pipe through the plurality of magnetic elements; It is characterized in that the first end of the core wire is fixedly retained at the first end of the tubular portion (22), and the second end of the core wire opposite to the first end is fixedly retained at the second end of the tubular portion (22), wherein the core wire (50) is elastically deformable to allow the plurality of magnetic elements (30) to be axially displaced relative to the core wire (50) when the device end (20) is bent.

18. A steerable device (10) for use in a mammal, comprising: - a flexible, elongated element (12) extending along a longitudinal axis (L) and configured to pass within a mammalian body; a flexible device tip (20) arranged at the distal end of the elongated element (12) and configured to allow the elongated element (12) to be steered by means of an external magnetic field, the device tip (20) comprising a tubular portion (22) and a plurality of permanent magnetic elements (30) arranged in an end-to-end manner in the tubular portion (22) with adjacent ends of opposite polarity and with their respective magnetic axes arranged along the longitudinal axis (L); Each magnetic element (30) has an axial hole (40), the axial hole (40) extending along the longitudinal axis of the magnetic element from a first axial end of the magnetic element to a second axial end of the magnetic element opposite to the first axial end, and the axial holes (40) of the plurality of magnetic elements form an axial conduit (46) passing through the plurality of magnetic elements (30); - a core wire (50) extending in the pipe through the plurality of magnetic elements; The invention is characterized in that a first end of the core wire is fixed at a first end of the tubular portion (22), and a second end of the core wire opposite to the first end is fixed at a second end of the tubular portion (22), wherein The length of the core wire (50) is greater than the axial length of the multiple magnetic elements (30), wherein the first end of the core wire and / or the second end of the core wire maintains a gap, and the gap is designed to allow the multiple magnetic elements (30) to be axially displaced relative to the core wire (50) when the end (20) of the device is bent.

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