A magnetically steerable device for use within the body of a mammal

Abstract

A steerable device for use within a mammalian body comprises a flexible elongate element (1) and a magnetic element (4) disposed at the distal end of the elongate element (1) to enable steering by an external magnetic field. The steerable device comprises a structure disposed proximal to the magnetic element and having a plurality of elongate protrusions formed on the outer surface of the elongate element. Each of the elongate protrusions has a protrusion longitudinal axis, each protrusion longitudinal axis is angled with respect to the device longitudinal axis, each angle being less than 90°, and clockwise rotation of the elongate element (1) about the device longitudinal axis (12) results in a forward movement of the elongate element (1) relative to the soft tissue. In a further aspect, the structure is in the form of an external thread structure (2).

Description

Technical Field

[0001] The present invention relates to a steerable device for use within the body of a mammal. The device may be a needle, guidewire, catheter, endoscope, or other flexible device designed to be inserted into the body of a mammal for diagnostic or interventional purposes.

Background Art

[0002] Many medical procedures require guiding a medical device to a specific location within the body. Examples include deep brain stimulation, organ biopsy, targeted drug delivery, tumor removal, etc. The insertion and guidance of such devices are performed in various ways depending on the application.

[0003] In the case of procedures within organs such as the brain or liver, a semi-rigid needle or guidewire is pushed through the soft tissue of the organ from the incision point to the target site. Since it is often almost or completely impossible to manipulate or direct the needle, the path from the incision point to the target site is substantially linear. The number of reachable target sites is very limited (for example, it is extremely difficult to reach the target site at a large angle from the incision point). Since these devices are relatively rigid, in order to guide them to various target sites within the organ, a separate path is required from the incision point to the target site. Therefore, there is a possibility of damaging the tissue between the insertion point and the target site. Friction between the soft tissue and the outer surface of the device can also be a problem. When the needle or guidewire is sufficiently flexible, buckling often occurs, further damaging the tissue and limiting the effectiveness of the procedure.

[0004] In the case of procedures within body cavities such as the abdomen or bladder, a flexible device is manipulated by pushing it proximally while usually rotating the pre-curved distal end either by a traction wire or otherwise. The ability of the device to reach the target site and the ability to advance without buckling are essentially in a trade-off relationship. That is, if the device is flexible enough to be steered from the insertion point to the target site at a large angle, it is likely to buckle or form loops during pushing.

[0005] In the case of treating a vascular structure, a catheter or guidewire is pushed into the blood vessel proximally and further manipulated to the target site by a traction wire or a pre-curved tip. Also in this case, there is a trade-off relationship between the rigidity required to push it in without buckling and the flexibility required to reach the target site. Since the device advances by being pushed in proximally, if the device deviates, it is often difficult to reach the target site deep in the vascular structure and may damage the blood vessel wall.

[0006] Among the proposed devices, there are those having a magnetic device tip that can make the device more flexible and enable more accurate control of the trajectory. However, since these devices also rely on pushing to advance, they face all of the above-mentioned problems. Furthermore, the hardness of the device required to enable pushing significantly limits the magnetic maneuverability.

[0007] U.S. Patent No. 7,815,580B2 discloses a magnetic induction guide wire designed to penetrate an occlusion within a vascular structure. The guide wire consists of an elongated wire with a tip. Proximal to the tip, a magnetic responsive element is disposed to maneuver the tip of the guide wire in response to an external magnetic field. On the surface of the tip, an outer helical thread is formed and used to screw into the blockage of an occluded blood vessel. The guide wire is typically pushed into the vascular structure until it normally hits the blockage. Then, the guide wire is rotated so that the helical thread at the tip penetrates the occlusion. When the guide wire is withdrawn from the vascular structure, the occlusion can be removed together with the guide wire, or a stent can be placed inside the occlusion. The helical thread extends only over a very short length at the tip and is designed only to pierce the blockage of the blood vessel at the tip. The purpose of the guide wire is to place a stent to relieve the vascular occlusion caused by the blockage. Therefore, the tip of the guide wire only needs to reach the blockage and penetrate the blockage with the assistance of the helical thread. The guide wire still relies on a pushing forward mechanism to reach the occlusion through the vascular structure with the tip of the guide wire, and to retract the guide wire, it must be pulled at the proximal end side of the guide wire. Since the helical thread does not extend beyond the outer surface of the guide wire body, it does not scrape the tissue of the blood vessel wall or damage it in other ways. Also, the helical thread is rigid for screwing into the blockage and is not flexible like the present invention.

[0008] U.S. Patent Application Publication No. 20100069718A1 discloses another catheter for insertion into a human body cavity. The distal portion of the catheter is covered by a helical thread structure and can be advanced by rotating the catheter by means of a so-called rotational advancement mechanism.

[0009] U.S. Patent Application Publication No. 2005272976A1 discloses an endoscopic insertion assisting device having a flexible tube and a tip member provided at the tip of the tube and having an outer diameter equal to or larger than the outer diameter of the tube. The tube has a helical structure on its outer peripheral surface.

[0010] International Publication No. WO 2021 / 126905 A1 and European Patent Application Publication No. EP 3643353 A1 disclose a miniature device that is maneuvered within a patient under the operation of an external magnetic field and configured to selectively execute a pre-specified function. The miniature device includes a shell that defines an internal cavity therein and a magnetic device disposed within the cavity. However, such a device does not form an elongated element having a proximal end of the maneuverable device on the opposite side of the distal end that remains outside the body of the mammal for external operation.

[0011] U.S. Patent Application Publication No. US 2019 / 060608 A1 discloses a catheter including an elongated shaft body and a tip member provided at the distal end of the shaft body. The shaft body may include a liner, a braided member surrounding the liner, a multi-layer coil surrounding the braided member, and a polymer cover surrounding the multi-layer coil. The outer surface portion of the polymer cover may include one or more spiral threads, and the one or more spiral threads may be covered with an outer wrapping material.

[0012] European Patent Application Publication No. EP 3854328 A1 discloses a dilator that can be advanced and / or retracted by rotation of a hollow shaft and can operate smoothly when linearly pushed in and / or pulled out. The dilator includes a hollow shaft including a tapered portion that expands in diameter from the distal end toward the proximal end, and a spiral protrusion provided on the outer peripheral surface of the hollow shaft and having a gap between adjacent portions along the axial direction of the hollow shaft.

[0013] European Patent Application Publication No. 3772317A1 relates to an endoscope for examining the digestive tract of mammals, particularly the small intestine of humans. The endoscope comprises an elongated flexible tube structure and a flexible elongated element disposed within the tube structure. The distal portion of the elongated element protrudes from the distal end of the tube structure and is connected to the endoscope tip. When the tube structure is rotated in a first direction around the elongated element, the gap between the endoscope tip and the distal end of the tube structure increases, i.e., the endoscope becomes longer. When the tube structure is rotated in a second direction opposite to the first direction around the elongated element, the gap between the endoscope tip and the distal end of the tube structure decreases, i.e., the endoscope becomes shorter. The elongated element engages with the tube structure in such a manner.

[0014] In an embodiment of European Patent Application Publication No. 3772317A1, the tube structure comprises a spiral outer surface structure forming a continuous structure, i.e., a groove that traces a spiral along the length of the tube structure. During the operation of the endoscope, the doctor transmits the rotation applied to the tube structure to the elongated element to move the endoscope tip forward. The movement of the endoscope is due to the continuous expansion and contraction of the endoscope with variable length. The movement of the endoscope tip is only indirectly connected to the rotation applied by the doctor to the tube structure. In fact, the movement of the tube structure can correspond to either the movement of the endoscope tip away from the tube structure remaining at a predetermined position or the movement of the tube structure in the direction of the endoscope tip remaining at a predetermined position. When miniaturization of the device is required, there are limitations due to the structure of the endoscope itself. Especially for the tube structure surrounding the elongated element that needs to transmit movement, there are limitations in reducing the diameter. That is, this concept is not suitable for the purpose of vascular intervention that typically has to be less than 4 mm in diameter, let alone for the human brain that requires a catheter thinner than 2 mm.

Summary of the Invention

[0015] An object of the present invention is to provide a device for use within the body of a mammal that can be used reliably and reproducibly in various applications for examination and / or surgery, diagnosis and / or intervention purposes within the body of a mammal, and is not affected by the limitations of the above-described device, particularly the trade-off between flexibility and pushability.

[0016] This object is achieved according to the invention by providing an apparatus comprising the features of claim 1 or 10. Further advantageous embodiments of the invention are the subject matter of the dependent claims.

[0017] The steerable device can be, for example, a needle, a guide wire, a catheter, an endoscope, etc. for use inside the body of a mammal, in particular a human, for example for examination and / or surgery. The steerable device may be used for examination and / or surgery inside an organ (for example, the liver, lung, kidney, brain, etc.), inside a body cavity (for example, the abdomen, spinal cord, sinus, etc.), or inside a vascular structure.

[0018] The device includes an elongate element that extends along the longitudinal axis of the device and is configured to enter the soft tissue of the mammal's body through an incision or other suitable means. The device tip can be disposed at the distal end of the elongate element. In particular, the distal side of the elongate element terminates at the device tip. The device tip may house or carry a measuring and / or driving device, such as, for example, a camera, a sensor, an ablation tip, a needle, an electrode, etc. The device may include a lumen that enables the delivery of fluids, needles, biopsy tools, etc. to the target site. The end of the device opposite the device tip, i.e., the proximal end of the device, is designed to remain outside the mammal's body for operation from the outside, for example, by a physician or a robot.

[0019] Also, the steerable device has a fixed length. That is, in contrast to European Patent Application Publication No. 3772317A1, which advances by continuously varying the device length, the length of a given steerable device according to the invention remains the same during the intervention.

[0020] The steerable device further includes a magnetic element disposed at the distal end of the elongated element and configured to steer the elongated element by an external magnetic field. The proximal end of the steerable device, opposite the distal end, remains outside the mammalian body for operating the steerable device from the outside. In a preferred embodiment, the magnetic element forms the foremost end of the steerable device and enables optimal steering of the steerable device. Preferably, the magnetic element is a permanent magnet element. In a preferred embodiment, the magnetic element is disposed at the tip of the device and includes or consists of at least one magneto-responsive element such that the external magnetic field can control the orientation of the device tip. In a preferred embodiment, the magnetic element includes a plurality of magnetic components distributed along the distal end of the elongated element, and by having a bending point between the magnetic components, a magnetic element that is easy to bend is formed.

[0021] One of the important inhibiting factors that prevent a conventional flexible medical device from advancing within the soft tissue of a mammalian body is friction. After traveling a certain distance, the friction between the elongated element and the soft tissue becomes too high, and the device cannot be effectively advanced continuously. In this case, the elongated element becomes impossible to push further or buckles, and in either case, the tip cannot be advanced further. All conventional flexible medical devices that rely on manual pushing for steering face a trade-off between flexibility and pushability.

[0022] According to one aspect of the present invention, the steerable device includes a structural portion disposed proximal to the magnetic element, the structural portion being formed on the outer surface of the elongated element and including a plurality of elongated protrusions each having a protrusion longitudinal axis, the protrusion longitudinal axis being angled with respect to the device longitudinal axis of the elongated element. The plurality of elongated protrusions form a plurality of angles with respect to the device longitudinal axis, and each of the plurality of angles is less than 90°. These angles are measured clockwise from the device longitudinal axis oriented in the proximal-to-distal direction. In such an arrangement, a clockwise rotation of the elongated element around the device longitudinal axis causes a forward movement of the elongated element relative to the soft tissue along the device longitudinal axis.

[0023] The structural portion has more wrinkles on its surface than the surface of the remaining portion of the elongated element that has not been structurally formed.

[0024] The principle of the present invention lies in combining a structural portion and a magnetic element in an operable device. Due to the rotation of the structural portion as described above, the elongated element advances within the soft tissue, and the magnetic element disposed distally of the structural portion enables accurate manipulation of the operable device.

[0025] The magnetic element is typically less flexible than the elongated element. Also, the elongated element provided with the structural portion is less flexible than when there is no structural portion. Therefore, it is advantageous to dispose the structural portion proximally to the magnetic element so as to avoid overlap between the structural portion and the magnetic element. As a result, the flexibility of the operable device is not excessively reduced, and the advancement is accurately maintained, for example, within a blood vessel or at a blood vessel bifurcation. For this reason, more preferably, the magnetic element is disposed in a non-structural portion. As a result, the distal end can be manipulated by a magnetic field with limited friction of the device.

[0026] In an embodiment where the structural portion is disposed proximally to the magnetic element, the distal end of the structural portion can at least partially overlap the magnetic element. As a result, the distal end is slightly stiffened by the elongated protrusion and the magnetic element, and buckling is reduced.

[0027] The configuration of the structural portion assists the advancement of the elongated element via a plurality of elongated elements when the elongated element is rotated clockwise. At the same time, the structural portion remains flexible and is more flexible than, in particular, a portion of the same length provided with a continuous thread, and has a simple design for manufacturing.

[0028] Due to the rotational movement, a pushing force is generated along the entire length of the elongated element with which the structural portion engages the surrounding soft tissue via the outer elongated element. Therefore, the device is flexible and does not face the above problems typically associated with flexible medical devices. By magnetic manipulation, the device can be controlled even while rotating, which cannot be achieved with conventional devices manipulated based on a traction wire or a pre-curved distal portion.

[0029] Advantageously, a structural part with a plurality of elongated protrusions can be manufactured even if there is a large tolerance regarding the orientation of the elongated protrusions as long as the angle formed with the longitudinal axis of the device is less than 90°. Therefore, the structural part can be manufactured easily and at low cost.

[0030] The plurality of angles are measured clockwise from the longitudinal axis of the device which is oriented in the proximal-to-distal direction. In other words, when the elongated element is oriented from proximal to distal, the longitudinal axis of the device is oriented, as seen on a clock, from 6 o'clock corresponding to the proximal to 12 o'clock corresponding to the distal, and the angle between the longitudinal axis of the device and the longitudinal axis of the protrusion is measured clockwise from 12 o'clock.

[0031] In a preferred embodiment, the plurality of angles have a single inclination angle selected from 5° to 80°. That is, all the angles of the plurality of angles have the same value. The advantage of having a single inclination angle is that the pushing force increases along the longitudinal axis of the device, but within the above range, when the manipulable device is rotated clockwise, the manipulable device can move forward from proximal to distal. In a more preferred embodiment, the single inclination angle is from 10° to 60°, whereby the pushing force along the longitudinal axis of the device is optimized. In an even more preferred embodiment, the single inclination angle is more preferably from 20° to 30°. This range has been shown by experiments to allow the manipulable device to move forward well. It should be understood that the "single inclination angle" is one value within the manufacturing tolerance. Therefore, it may include a plurality of values, and in that case, the plurality of values are dispersed around a single inclination angle which is the median value within the manufacturing tolerance.

[0032] The elongated protrusion may be elliptical with the major axis forming the longitudinal axis of the protrusion. Other elongated shapes are also possible, for example, a rectangle whose long side defines the longitudinal axis of the protrusion.

[0033] The plurality of elongated protrusions are spaced apart from each other. That is, there is no contact area common to two elongated protrusions.

[0034] Also, each of the plurality of elongated protrusions has a circumferential length that is shorter than that around the elongated element in the structural region where the elongated protrusions are disposed. In other words, when viewed in the longitudinal direction, the plurality of elongated protrusions extend less than one full circle around the elongated element. These extend only to a part of the periphery of the elongated element and are spaced apart from each other. This is in contrast to a helical structure that extends continuously in the longitudinal direction over more than one full circle.

[0035] The circumferential range of the elongated protrusion is measured in a plane perpendicular to the longitudinal axis of the device and can be characterized by a sector defined by projecting the radii intersecting the proximal and distal ends of the elongated protrusion onto this plane, respectively. As described above, since the plurality of elongated protrusions have a longitudinal length shorter than that around the elongated element, the above sector is less than 360°.

[0036] In a preferred embodiment, the sectors of the plurality of elongated protrusions are in the range of 30° to 150°. Preferably, the angle of the sector is 60° to 120°. On the one hand, the range of the elongated protrusion is wide enough to engage the surrounding soft tissue, but on the other hand, the range of the elongated protrusion is not so wide as to significantly reduce the flexibility of the manipulable device in the structure. Preferably, the angle of the above sector is 100°. This configuration optimizes any of the above aspects.

[0037] In a preferred embodiment, two consecutive elongated protrusions among the plurality of elongated protrusions at least partially overlap in the circumferential direction. In other words, the sector angles defined by two consecutive depressions overlap. Preferably, the sector angles overlap by 10% to 30% of the sector angle, respectively. More preferably, the sector angles overlap by 20% each. By the overlapping of two consecutive elongated protrusions, the regions engaging the surrounding soft tissue are continuously connected. As a result, a continuous engagement with the surrounding soft tissue that promotes the advancement of the manipulable device is formed. The overlapping of the sector angles defined by two consecutive elongated protrusions does not mean that the elongated protrusions have an intersection. In fact, whether an intersection is provided also depends on the axial range of the elongated protrusion.

[0038] In a preferred embodiment, the plurality of elongated protrusions are aligned along a thread path having a thread path angle equal to the one inclination angle. The thread path angle is defined as the angle of the thread path as viewed from the side with respect to the longitudinal axis of the device. In this embodiment, the thread path forms a discontinuous thread helix. The alignment of the elongated protrusions along the thread path, particularly the helical path, further improves the forward movement ability of the device that can be maneuvered during rotation. This ensures the dispersion of a uniform force distribution around the structural part throughout the entire structural part and improves the control of the forward movement.

[0039] Preferably, the thread path extends at least one turn from the proximal end to the distal end of the structural region. This embodiment guarantees stability over the length of the structural part. More preferably, the helical path extends multiple turns from the proximal end to the distal end. As a result of experiments, it has been found that in this case, the stability is optimized over the length of the structural part.

[0040] In an even more preferred embodiment, the plurality of elongated protrusions overlap end to end and form a continuous thread on the outer surface of the elongated element. The continuous thread formed by these elongated protrusions ensures a uniform force distribution around the structural part and improves the control of the forward movement.

[0041] In a preferred embodiment, the plurality of angles have at least two inclination angles, and the inclination angles are selected from 5° to 80°. In a more preferred embodiment, at least two inclination angles are selected from 20° to 60°, and more preferably, at least two inclination angles are selected from 20° to 30°. The advantage of at least two inclination angles is that the pushing force along the longitudinal axis of the device can be optimized depending on the angle at which the steerable device contacts the soft tissue. Since an elongate element having one of the at least two inclination angles cannot properly contact the soft tissue at this one angle and does not assist in the advancement of the steerable device, an elongate element having another value of the at least two inclination angles can assist in the advancement of the steerable device. In an even more preferred embodiment, the plurality of angles have two inclination angles, and these two inclination angles are selected from 20° to 60°. That is, all of the angles among the plurality of angles are selected from a set of two inclination angles. More preferably, these two inclination angles are selected from 20° to 30°. In an embodiment with only two inclination angles, a balance between improved advancement and manufacturing complexity is achieved. In a more preferred embodiment, these two inclination angles are separated by 30° to 60°. By separating these two inclination angles from each other, contact with the soft tissue can be optimized.

[0042] In a preferred embodiment where the plurality of angles have at least two inclination angles, the plurality of elongate protrusions are aligned along at least two thread paths, and each of the at least two thread paths has a thread path angle equal to one of the at least two inclination angles. Preferably, the at least two thread paths extend at least one turn from the proximal end to the distal end of the structural region. The features regarding the elongate protrusions described in connection with an embodiment having one thread path can be similarly applied to an embodiment having at least two thread paths.

[0043] In a preferred embodiment, the outer tubular structure surrounds a portion of the elongated element, and the tubular structure includes an engagement element configured to engage a plurality of elongated protrusions such that rotation of the elongated element about the longitudinal axis of the device causes movement of the elongated element relative to the tubular structure along the longitudinal axis of the device. The tubular structure will be described in more detail in connection with the following further embodiments. Similar effects and advantages associated with the tubular structure apply to this embodiment.

[0044] In a preferred embodiment, the plurality of elongated protrusions have a triangular cross-section to improve contact with soft tissue. In a preferred embodiment, the plurality of elongated protrusions have a circular cross-section to obtain a smooth contact surface with soft tissue. In a preferred embodiment, the plurality of elongated protrusions have a convex cross-section, preferably a substantially sinusoidal cross-section, to obtain a smoother contact surface with soft tissue.

[0045] In a preferred embodiment, the structural portion is interposed with a plurality of non-structural portions where no elongated protrusions are provided. The non-structural portions are more flexible, and the flexibility of the elongated element decreases in the structural portion. This embodiment constitutes a steerable device having a portion with higher flexibility, i.e., the non-structural portion, and a portion that alleviates the decrease in flexibility of the structural portion, and as a result, optimizes the forward movement ability of the steerable device.

[0046] In a more preferred embodiment, some of the plurality of non-structural portions have the same length and are spaced apart from each other at a constant pitch. This simple design also provides a uniform flexibility profile along the longitudinal axis of the device, so that the steerable device can be more easily controlled.

[0047] The elongated protrusions can be made of a material suitable for biomedical applications. In particular, in order to avoid interaction with the magnetic field applied to manipulate the elongated element, it may be made of a magnetically non-responsive material, for example, a non-ferromagnetic material. For example, suitable materials can be polymer materials such as nylon, polyurethane, polyethylene, polyether block amide (for example, known under the trade name of Pebax®), or silicone.

[0048] Also disclosed is an embodiment of a steerable device in which a flexible elongate element extends along the longitudinal axis of the device and is configured to enter the soft tissue of a mammalian body.

[0049] Furthermore, the magnetic element is disposed at the distal end of the elongate element and is configured to enable steering of the elongate element by an external magnetic field. The proximal end of the steerable device, on the side opposite the distal end, remains outside the mammalian body for operating the steerable device from the outside. The magnetic element is less flexible than the elongate element and is advantageously disposed at the distal end that can be more easily advanced and more accurately oriented, for example, within a blood vessel or at a blood vessel bifurcation, while steering the steerable device. The magnetic element includes, or consists of, at least one magnetically responsive element such that the external magnetic field can control the orientation of the device tip. Preferably, the magnetic element is a permanent magnet element.

[0050] The magnetic element responds to the external magnetic field and thus enables steering control of the elongate element. The magnetic field can be generated by a device disposed outside the mammalian body or by other suitable means.

[0051] In a further aspect of the invention, the steerable device includes a structure in the shape of an external thread structure that is formed on the outer surface of the elongate element and has a radial extent beyond the outer surface of the elongate element. In a preferred embodiment, the thread structure is a helical thread structure. The thread structure may have a helical screw shape.

[0052] Also, the steerable device has a fixed length. That is, in contrast to European Patent Application Publication No. 3772317A1, which advances by continuously varying the device length, the length of a given steerable device according to the present invention remains the same during the intervention. The diameter of the elongate element is substantially the same and preferably the same throughout the length of the steerable device.

[0053] According to the present invention, the thread structure is made of a magnetically non-responsive material and is configured to engage with the soft tissue surrounding the elongated element within the mammalian body such that rotation of the elongated element about the longitudinal axis of the device causes movement of the elongated element relative to the soft tissue along the longitudinal axis of the device.

[0054] Rotation of the thread structure causes the elongated element to advance within the soft tissue, and the device can be maneuvered by the magnetic element. The structure, i.e., the configuration of the thread structure, assists the advancement of the elongated element when rotated clockwise. Due to the rotational movement, a pushing force is generated along the entire length of the elongated element where the thread structure engages with the surrounding soft tissue via the outer elongated element. Thus, the device is extremely flexible and does not face the above problems typically associated with flexible medical devices. With magnetic maneuvering, the device can be controlled even while rotating, which is not possible with conventional devices that are maneuvered based on a traction device wire or a pre-curved distal portion.

[0055] The thread structure can be formed from a wire wound around the elongated element along its length. Alternatively, the thread structure may be an extrusion formed on the outer wall of the elongated element.

[0056] The thread structure is made of a magnetically non-responsive material to avoid the interaction between the magnetic field applied to maneuver the magnetic element and the thread structure, which would cause the deviation of the path of the maneuverable device. This embodiment enables the optimization of the maneuvering. For example, the magnetically non-responsive material can be a non-ferromagnetic material. However, it may also be a diamagnetic or paramagnetic material with a magnetic contribution that can be ignored compared to the magnetic contribution of the magnetic element to the maneuvering of the device. With these properties, the interaction between the outer thread device structure and the magnetic field is much smaller than the interaction between the magnetic element and the magnetic field and thus should not be considered when maneuvering a device that can be maneuvered within the mammalian body.

[0057] In a preferred embodiment, the thread structure has a triangular cross-section to improve contact with soft tissue. In a preferred embodiment, the thread structure has a circular cross-section to obtain a smooth contact surface with soft tissue. In a further preferred embodiment, the thread structure has a convex cross-section, preferably a substantially sinusoidal cross-section, to obtain an even smoother contact surface with soft tissue. The convex cross-section has the further advantage of avoiding the formation of a gap between the thread structure and the outer surface of the elongate element.

[0058] In a preferred embodiment, the thread structure has a plurality of non-structured portions where the thread structure is not provided interposed therebetween. The non-structured portions have a higher flexibility, and the thread structure has a reduced flexibility. This embodiment enables the construction of a steerable device having a higher flexibility, i.e., having non-structured portions, that alleviates the reduction in the flexibility of the thread structure and, as a result, optimizes the forward movement ability of the steerable device.

[0059] Also, according to the present invention, the thread structure is disposed proximal to the magnetic element. The magnetic element is typically less flexible than the elongate element. Also, the elongate element having the thread structure is less flexible than when there is no thread structure. Thus, it is advantageous to avoid an overlap between the thread structure and the magnetic element so that the forward movement is accurately maintained, for example, in a blood vessel or at a blood vessel bifurcation, without an excessive reduction in the flexibility of the steerable device. For this reason, more preferably, the magnetic element is disposed in the non-structured portion. As a result, the distal end portion is steerable by a magnetic field with limited friction of the device.

[0060] In a preferred embodiment, the radial range of the thread structure measured from the outer surface of the elongate element has a first value in a first portion of the structured portion and a second value different from the first value in a second portion of the structured portion disposed proximal to the first portion, whereby the flexibility of the first portion and the second portion is different. This embodiment enables the construction of the flexibility of the thread structure itself. In a further preferred embodiment, the second value is greater than the first value, and the radial range decreases from the second value to the first value in the distal direction, i.e., towards the distal end of the device.

[0061] The thread structure extends radially beyond the outer surface of the elongated element. This has the advantage that the thread structure itself penetrates into the soft tissue around the elongated element, and when the elongated element rotates around the longitudinal axis of the device, a propulsive force can be generated along the longitudinal axis of the device.

[0062] The force pushing the elongated element forward is generated by rotational engagement with the soft tissue, so that a propulsive force is generated at all points along the elongated element where the thread structure engages with the soft tissue. Therefore, the elongated element can be designed to have higher flexibility and / or elasticity without the risk of buckling of the elongated element compared to a device that relies solely on proximal pushing for propulsion. Furthermore, since the rotation angle determines the linear momentum, both the forward movement of the device towards the distal end side and the backward movement, i.e., the retraction, of the proximal end side of the steerable device can be controlled more accurately.

[0063] The longitudinal axis of the device, i.e., the center line, should be interpreted as a line passing through the center of the elongated element, in other words, a line connecting the centers of all cross-sectional circles obtained when viewing any cross-section of the elongated element along the length of the elongated element.

[0064] When moving within soft tissue such as the brain or liver, the elongated element may be steered along a curved path or follow a curved path. In a preferred embodiment, the magnetic element is disposed at the tip of the device. In contrast to conventional steering based on a traction wire, by utilizing magnetic steering, the device can be made more flexible, enabling steering while rotating, which was impossible with a traction wire. In a preferred embodiment, the tip of the device forms the foremost end of the steerable device, enabling optimal steering of the steerable device. In particular, the tip of the device itself may be a magnetic body and may function as the magnetic element described herein.

[0065] Since the device produces forward and backward movement by utilizing rotational motion, it can be made more flexible than conventional devices that rely on pushing and pulling on the proximal side for movement. This flexibility is important for enabling the device to be magnetically and effectively maneuvered. This is because the forces generated by magnetic manipulation are considerably lower compared to the forces associated with conventional manipulation methods (e.g., traction wires). Furthermore, when the device is maneuvered along a tortuous path, due to the nature of the rotational motion mechanism, the device can continue to move forward or backward without the risk of buckling or tissue cutting. Along with this, the rotational motion mechanism and remote magnetic manipulation enable the device to move along complex and tortuous paths, which was impossible with conventional devices.

[0066] According to an advantageous embodiment, the thread structure is formed along at least 10%, 50%, or 80% of the length of the elongate element. The longer the thread structure, the more the force for advancing the elongate element is distributed along the length of the elongate element.

[0067] The engagement of the thread structure with the soft tissue stabilizes the device, and the device will not be pushed back even when an instrument is inserted into the device and pushed into the target site (e.g., for injection). Also, the instrument passed through the device can apply a greater tensile force to the tissue at the target site than would be possible with such a flexible device (e.g., for taking a specimen). In some embodiments, the elongate element comprises two or more thread structures spaced along the length of the elongate element.

[0068] Preferably, the thread structure has a thread path angle of 5° to 60°. In particular, the thread path angle of the thread structure should be sufficient for the intermediate gap between the threads to engage with the soft tissue.

[0069] Preferably, the overall diameter of the device is at most 15 mm for body cavities, at most 6 mm for organs, and at most 3 mm for vascular structures.

[0070] Advantageously, the thread structure has a thickness measured radially from the outer surface of the elongate element that is 5% to 15% of the diameter of the elongate element, particularly the outer diameter of the elongate element.

[0071] In a preferred embodiment, the magnetic element includes a plurality of magnetic components distributed along the distal end portion of the elongated element, and by having a bending point between the magnetic components, a magnetic element that bends is formed.

[0072] In a preferred embodiment, a part of the elongated element is surrounded by an outer tubular structure such as a sheath. The tubular structure may be flexible. In particular, the elongated element and the tubular structure may be arranged concentrically or substantially concentrically.

[0073] Advantageously, the tubular structure includes an engagement element configured to engage with a thread structure such that rotation of the elongated element around the longitudinal axis of the device causes movement of the elongated element relative to the tubular structure along the longitudinal axis of the device. In particular, the engagement element, such as a protruding element like a pin, peg, or bearing ball, may reach the threads of the thread structure, or in the case of a plurality of elongated protrusions, reach them, and convert the rotation of the elongated element relative to the engagement element into a translational movement of the elongated element relative to the engagement element. In particular, the engagement element may be a female thread with a few turns, which is complementary to the thread structure and provided on the inner wall of the tubular structure. This feature assists in the controlled advancement of the steerable device because the tubular structure can function as a temporary anchor against which the elongated element is pressed forward or backward. The tubular structure imparts stiffness to the device and / or reduces the amount of contact between the soft tissue and the threads, or in the case of a plurality of elongated protrusions, reduces the amount of contact between the soft tissue and these.

[0074] In a preferred embodiment, the engagement element may be designed to seal the thread structure to prevent backflow of body fluid, or may be designed to allow fluid to be injected into the tubular structure and sent into the body.

[0075] Advantageously, the elongate element freely passes through the lumen of the tubular structure and is attached to the tubular structure only via this rotational engagement mechanism. In particular, there is no limitation on the range of linear movement due to attachment to the tubular structure for the elongate element. Preferably, a portion of the elongate element that extends outside the tubular structure and is disposed between the device tip and the distal end of the tubular structure is exposed, particularly exposed to the surrounding soft tissue environment. That is, it is not protected more than other parts of the steerable device.

[0076] In a preferred embodiment, the threaded structure is freely wound around the elongate element, the distal end of the threaded structure is fixed to the elongate element, the proximal end of the threaded structure is removably fixed to the elongate element, and by displacing the proximal end proximally or distally in the longitudinal direction, that is, by stretching or contracting the threaded structure, the thread pitch can be changed. This embodiment has the advantage that, when contact with the soft tissue is not appropriate to assist forward movement at a given thread pitch, the thread pitch can be changed, that is, contracted or extended, or, for example, both can be repeated alternately, to better assist the forward movement of the steerable device.

[0077] In a preferred embodiment, the threaded structure is freely wound around the elongate element and, in a first rotational direction of the elongate element, engages with the threaded structure to transmit the rotational movement of the elongate element to the threaded structure, and in a second rotational direction opposite to the first rotational direction, is fixed to the elongate element by locking means that disengages the threaded structure to make the threaded structure rotatable. Advantageously, this embodiment enables control of the friction with the surrounding soft tissue, which is harmful to the safe forward movement of the steerable device.

[0078] In an even more preferred embodiment, the locking means is retractable and makes the threaded structure rotatable in the first rotational direction and the second rotational direction. Advantageously, this embodiment releases the outer thread that engages with the surrounding soft tissue when it is harmful to the safe forward movement of the steerable device, such as when the outer thread is blocked or the friction with the surrounding soft tissue is too great.

[0079] The elongate element should have sufficient flexibility to follow a tortuous path along soft tissue within the body. On the other hand, the elongate element should have sufficient rotational stiffness to directly transmit torque applied to the proximal portion of the elongate element along the length of the elongate element to a more distal portion where the thread structure is located. Such direct torque transmission is particularly important for the rotational movement mechanism described above. The longitudinal flexibility on one hand and torsional stiffness on the other hand may be achieved, for example, by a combination of the material and design characteristics of the elongate element, such as using multiple tubular layers or hollow twisted coils as described below.

[0080] Advantageously, the elongate element includes a plurality of concentrically arranged tubular layers. Advantageously, at least two or three concentrically arranged tubular layers are laminated along the radial direction, i.e., along the thickness of the elongate element.

[0081] In a preferred embodiment, the elongate element includes at least one tubular layer formed from a plurality of wires, particularly metallic wires such as made of a stainless steel alloy, and the plurality of wires are spirally wound along the direction of the longitudinal axis of the device along the tubular surface such that the plurality of wires are densely arranged in a row. In other words, in a cross-sectional view of the tubular layer whose cross-section is perpendicular to the longitudinal axis of the device of the elongate element, the wire cross-sections of each wire constitute the circumference of the tubular layer. Preferably, the tubular layer consists of at least 7, 9, or 11 wires. Such a tubular layer may be a so-called twisted hollow coil body described in European Patent Application Publication No. 1428547A2, or a so-called hollow twisted coil described in European Patent Application Publication No. 2263736A1.

[0082] In an advantageous embodiment, the wires of one of the tubular layers are wound in a direction opposite to the wires of another of the tubular layers. That is, when looking at the cross-section of the elongate element and tracing along the length of the elongate element, the wire wound around one tubular layer rotates in one direction and the wire wound around another tubular layer rotates in the opposite direction. Preferably, the tubular layers having wires wound in opposite directions are arranged directly adjacent to each other in the elongate element. More preferably, the winding directions of consecutive tubular layers alternate between one tubular layer and the adjacent tubular layer over three or more tubular layers.

[0083] According to another embodiment, the elongate element includes a tubular layer having holes along its length and circumference. The flexibility of the elongate element is determined by the size and distribution of the holes in the tubular layer. Instead of or in addition to the holes, the tubular layer may also comprise depressions distributed along the length and circumference of the tubular layer. In particular, the distribution of the holes or depressions along the length of the tubular layer may be periodic.

[0084] Advantageously, the tubular layer comprises slits extending along its surface in a circumferential or helical direction. Each slit extends across the entire circumference of the tubular layer and may be interrupted at two or more points by bridges.

[0085] The elongate element may include a plurality of portions having different flexibilities along its length. For example, the distal portion towards the device tip may have increased flexibility compared to the rest of the elongate element, enabling more effective magnetic manipulation at the narrow location.

[0086] The elongate element may comprise a lumen through which medical devices such as needles and biopsy tools, and fluids such as drugs, contrast agents, coagulants, solutions, etc., may be delivered to a desired site within the body of a mammal, in particular via the distal side terminal of the lumen at the device tip.

[0087] Also disclosed is the use of a steerable device according to any one of the above-described embodiments in conjunction with a medical system comprising a magnetic field generator designed to generate a magnetic field having a predetermined direction, amplitude, and spatial variation, which is applied to the steerable device, and a unit designed to impart a rotational movement to the steerable device. The medical system enables various applications for examination and / or surgery, diagnosis and / or intervention purposes within the body of a mammal. Preferably, the magnetic field generator is in the form of a magnetic induction system comprising a plurality of electromagnetic or permanent magnets that are movable and installed around the patient and that provide a non-uniform magnetic field at a predetermined position in the space in which the steerable device is moved.

[0088] The terms proximal and distal used herein are used with reference to the position of the physician using the steerable device. Thus, the term distal refers to a component, part, or direction that is oriented or disposed towards the interior of the patient where the physician cannot directly manipulate the part by hand. Similarly, the term proximal refers to a component, part, or direction that is located at or oriented towards the location of the physician. In particular, the proximal end refers to the end of an elongated element that extends outside the incision during use. That is, the proximal end of the elongated element extends outside the body of the mammal during use. On the other hand, the distal end of the elongated element refers to the end of the elongated element that is inside the patient's body during the procedure.

[0089] With reference to the accompanying schematic drawings, some examples of embodiments of the present invention will be described in detail below.

Brief Description of the Drawings

[0090]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

[0091] FIG. 1 is a cross-sectional view of an operable device according to one possible embodiment. In this embodiment, the device includes an elongated element 1 having a device tip 3 at its distal end. The elongated element 1 has a wall 11 surrounding a lumen 10, and the lumen 10 extends along the longitudinal axis of the device. Various medical devices and / or substances are supplied through the lumen 10 of the elongated element 1 and can exit from the device tip 3 to a desired site in the body.

[0092] The elongated element 1 has a structural region in the shape of a thread structure 2 that surrounds the outer surface of the elongated element 1. The thread structure 2 is formed as a spiral screw that is spirally wound around the outer surface of the elongated element 1 and extends to the device tip 3. When the device is inserted into soft tissues of a mammalian body, such as an organ, a body cavity, a blood vessel, or other soft tissues, from an incision wound, the thread structure 2 engages with the tissues around the elongated element 1, causing the rotation of the elongated element 1 to result in the forward or backward movement of the elongated element along the longitudinal axis of the device. The device may move in the forward direction or the backward direction depending on the rotation direction of the elongated element 1.

[0093] The device tip 3 is a magnetic body, that is, part or all of it is made of a magnetically responsive material. This is one of the possible embodiments in which the magnetic element 4 is arranged at or near the device tip 3.

[0094] A somewhat different embodiment of the steerable device is shown in FIG. 2. Here, the thread structure 2 does not extend entirely to the device tip 3. Instead, the magnetic element 4, designed as a plurality of magnetic components in the shape of a magnet ring, is arranged at equal intervals in the gap between the device tip 3 and the distal end of the thread structure 2. The magnet ring increases the effect of the magnetic field on the operation of the device while maintaining the flexibility of the elongated element between the magnet rings.

[0095] A further embodiment of the steerable device having a configuration similar to that of the embodiment of FIG. 1 is disclosed in FIG. 11. In this case, a plurality of non-structural parts 106, which do not have a thread structure and are more flexible, are interposed in the thread structure 2.

[0096] In an embodiment of the steerable device having a configuration similar to that of the embodiment of FIG. 1 and disclosed in FIG. 12, the radial extent of the thread structure 2 measured from the outer surface of the elongate element 1 has a first value at the distal portion 108 of the structure portion and a second value greater than the first value at the proximal portion 110 of the structure portion. The radial extent decreases from the second value to the first value in the distal direction, i.e., towards the tip of the steerable device. In an embodiment where the cross-section of the thread structure 2 is circular, the radial extent corresponds to the diameter of the thread structure 2, which is larger at the distal portion 108 than at the proximal portion 110.

[0097] In an embodiment of the steerable device having a configuration similar to that of the embodiment of FIG. 1 and shown in FIG. 13, the thread structure 2 has a thread pitch 112 that increases in value from distal to proximal, so that the flexibility increases from distal to proximal.

[0098] Yet another embodiment of the steerable device is shown in FIG. 3. This embodiment differs from that shown in FIG. 1 in that a portion of the elongate element 1 is surrounded by an outer tubular structure 5. The tubular structure 5 includes an engagement element 6 that engages a portion of the thread structure 2 such that relative rotation between the elongate element 1 and the tubular structure 5 causes the elongate element 1 to translate relative to the tubular structure 5. This feature helps to secure the device and improve the ability of the elongate element to advance and / or retract, and also provides another lumen for injecting fluid.

[0099] FIG. 4 shows a cross-sectional view of an embodiment of a steerable device, such as the embodiment of FIG. 1, in a curved or bent state. As can be seen here, when the elongate element 1 is not in a straight state, the device longitudinal axis 12 of the elongate element 1 can be curved.

[0100] Cross-sectional views of exemplary embodiments of the thread structure, although contemplated but not limited thereto, are disclosed in FIGS. 14, 15, and 16, and reference is made to the enlarged area A of the exemplary embodiment of the operable device shown in FIG. 11. Note that the disclosed cross-sectional view may be a cross-section of an elongated protrusion similar to that disclosed in FIGS. 8, 9, and 10. In FIG. 14, the thread structure 2 has a triangular cross-section to improve contact with soft tissue. In FIG. 16, the thread structure 2 has a circular cross-section to obtain a smooth contact surface with soft tissue. In FIG. 15, the thread structure 2 has a convex cross-section in the shape of a sine curve to obtain a smooth contact surface with soft tissue and avoid the formation of a gap between the thread structure 2 and the outer surface of the elongated element.

[0101] A detailed view of the structure of the elongated element 1 according to a preferred embodiment is shown in FIG. 5. The elongated element is formed from a first tubular layer 7 and a second tubular layer 8, and the second tubular layer 8 has a smaller diameter and is fitted inside the first tubular layer 7. FIG. 5 is a cutaway view in which the left side portion of the first tubular layer 7 is removed and the second tubular layer 8 hidden thereunder is visible.

[0102] Each tubular layer 7, 8 is formed from a plurality of wires. As an example, the first tubular layer 7 is formed from twelve wires 71, 72, 73, and each wire is spirally wound to form the surface of the tubular layer 7. The wires 71, 72, 73 together form the first tubular layer 7. The second tubular layer 8 is formed in the same manner but has a smaller overall diameter. Further, the wires of the first tubular layer 7 are wound in a direction opposite to that of the wires of the second tubular layer 8. The spiral structure 2 is formed on the outer surface of the first tubular layer 7. It consists of one wire wound in the same manner as any of the wires 71, 72, 73 of the first tubular layer 7.

[0103] Figure 6 shows a tubular layer 9 according to another embodiment for use in the elongate element 1. This tubular layer 7 consists of a rigid tube that is perforated to adjust the bending stiffness of the tubular layer. The holes 91 are formed as annular slits along the length of the tubular layer 9. A plurality of concentrically arranged tubular layers of this kind may be combined to form the elongate element 1. Alternatively, a tubular layer of this kind may be combined with one or more of the tubular layers 7, 8 shown in Figure 5.

[0104] The steerable device disclosed in Figure 7 includes an elongate element 1 extending along a device longitudinal axis 12 and a device tip 3 disposed at a distal end of the elongate element 1. The device tip 3 is a magnetic body, that is, part or all of it is made of a magnetically responsive material, enabling the steering of the steerable device in a magnetic field.

[0105] The steerable device also includes a structure 100 having a plurality of elongate protrusions 102. In this embodiment, the structure 100 has a plurality of non-structural portions 106 where no elongate protrusions are provided, here two non-structural portions are interposed.

[0106] As can be seen in detail in Figures 8, 9, and 10, each of the plurality of elongate protrusions 102 of the structure 100 defines a protrusion longitudinal axis 104. The above part has a proximal end 110 and a distal end 108. Each of the protrusion longitudinal axes 104 defines angles α1, α2 with the device longitudinal axis 12, and the plurality of elongate protrusions 102 form a plurality of angles, and the plurality of angles measured clockwise from the device longitudinal axis 12 oriented in the proximal-to-distal direction are each less than 90°. In other words, in Figures 8, 9, and 10, the proximal-to-distal direction corresponds to the direction from the bottom to the top of the drawing. As a result of such an arrangement of the elongate protrusions, rotation of the elongate element 1 around the device longitudinal axis 12 causes movement of the elongate element relative to the soft tissue along the device longitudinal axis. For clarity, only some of the protrusion longitudinal axis 104 and the angles α1, α2 are shown.

[0107] In the embodiments of FIGS. 8 and 9, the elongated protrusion is substantially elliptical in shape, and the major axis of the ellipse defines the longitudinal axis 104 of the protrusion. In the embodiment of FIG. 8, the plurality of angles have two inclination angles α1 and α2, α1 is about 60°, and α2 is about 30°. In this embodiment, the angles α1 and α2 have a difference value of about 30° from each other. In the embodiment of FIG. 9, the plurality of angles have one inclination angle α1. Further, the plurality of elongated protrusions 102 are aligned along a thread path having a thread path angle equal to the inclination angle α1 and a thread pitch 112. In this embodiment, the thread path forms a discontinuous thread helix, but only the visible side is illustrated.

[0108] In the embodiment of FIG. 10, the elongated protrusion has a substantially rectangular shape, the length of the rectangle defines the longitudinal axis 104 of the protrusion, and the longitudinal axis 104 of the protrusion forms an angle α1 with the longitudinal axis 12 of the device. Note that the plurality of angles have one inclination angle α1.

Explanation of Reference Numerals

[0109] 1 Elongated element 10 Lumen of the elongated element 11 Wall of the elongated element 12 Longitudinal axis of the device 2 Outer thread structure 3 Device tip 4 Magnet ring 5 Tubular structure 6 Engaging element 7 (First) tubular layer 71, 72, 73 Wires 8 Second tubular layer 9 Tubular layer, further embodiments 91 Annular slit, hole 100 Structural part 102 Elongated protrusion 104 Longitudinal axis of the protrusion 106 Non-structural part 110 Proximal end of the structural part 108 Distal end of the structural part 112 Thread pitch

Claims

1. A controllable device used inside a mammal, A flexible, elongated element (1) extends along the longitudinal axis (12) of the device and is configured to enter the soft tissues of a mammal's body, A magnetic element (4) is positioned at the distal end of the elongated element (1) and is configured to enable the elongated element (1) to be manipulated by an external magnetic field. The slender element is provided, and the proximal end of the slender element extends outside the mammal's body when in use. A controllable device comprising a structural part (100) positioned proximal to the magnetic element (4), and comprising a plurality of elongated projections (102) formed on the outer surface of the elongated element, each having a projection length axis (104), wherein each projection length axis forms an angle (α1, α2) with the longitudinal axis of the device, the plurality of elongated projections (102) form a plurality of angles (α1, α2) with the longitudinal axis of the device, and each of the plurality of angles measured clockwise from the longitudinal axis of the device, which is oriented in a proximal to distal direction, is less than 90°, and the clockwise rotation of the elongated element (1) around the longitudinal axis of the device (12) causes the elongated element (1) to move forward relative to the soft tissue along the longitudinal axis of the device (12).

2. The apparatus according to claim 1, characterized in that each of the plurality of elongated protrusions (102) extends less than one full turn around the elongated element (1) when viewed from the longitudinal direction.

3. The apparatus according to claim 1 or 2, characterized in that each of the plurality of angles (α1, α2) has the same single inclination angle selected from 5° to 80°, preferably 10° to 60°, and more preferably 20° to 30°.

4. The apparatus according to claim 3, characterized in that the plurality of elongated protrusions (102) are aligned along a thread extending along the elongated element (1), and the thread has a thread path angle equal to the inclination angle of one of the threads.

5. The apparatus according to claim 1 or 2, characterized in that the plurality of angles (α1, α2) are distributed according to at least two inclination angles, and at least two of the inclination angles are selected from 5° to 80°, preferably 10° to 60°, and more preferably 20° to 30°.

6. The apparatus according to claim 5, characterized in that the plurality of elongated protrusions (102) are aligned along at least two threads having a thread path angle equal to one of the two inclination angles (α1, α2).

7. The apparatus according to claim 3, wherein the outer tubular structure (5) surrounds a portion of the elongated element (1), and the tubular structure (5) includes an engaging element (6) configured to engage with the plurality of elongated protrusions (102) such that rotation of the elongated element (1) about the longitudinal axis (12) of the apparatus causes movement of the elongated element (1) relative to the tubular structure (5) along the longitudinal axis (12) of the apparatus.

8. The apparatus according to claim 1 or 2, characterized in that the plurality of elongated protrusions (102) have a triangular cross-section, a circular cross-section, or a convex cross-section, preferably a substantially sinusoidal cross-section.

9. The apparatus according to claim 1 or 2, characterized in that the structural part (100) has a plurality of non-structural parts (106) interposed therebetween, which are not provided with elongated protrusions (102).

10. A controllable device used inside a mammal, A flexible, elongated element (1) extends along the longitudinal axis (12) of the device and is configured to enter the soft tissues of a mammal's body, A magnetic element (4) is positioned at the distal end of the elongated element (1) and is configured to enable the elongated element (1) to be manipulated by an external magnetic field. The slender element is provided, and the proximal end of the slender element extends outside the mammal's body when in use. The structural part (100) with the shape of an external screw thread structure (2) is formed on the outer surface of the elongated element (1), and has a radial range extending beyond the outer surface of the elongated element (1). A maneuverable device characterized in that the thread structure (2) is located proximal to the magnetic element (4), is made of a magnetically non-responsive material, and is configured to engage with the soft tissue surrounding the elongated element (1) within the body of a mammal such that the rotation of the elongated element (1) around the longitudinal axis (12) of the device results in the movement of the elongated element (1) relative to the soft tissue along the longitudinal axis (12) of the device.

11. The apparatus according to claim 10, characterized in that the screw thread structure (2) has a triangular cross-section, a circular cross-section, or a convex cross-section, preferably a substantially sinusoidal cross-section.

12. The apparatus according to claim 10 or 11, characterized in that the structural part (100) has a plurality of non-structural parts (106) interposed therein that do not have the screw thread structure (2).

13. The apparatus according to claim 10 or 11, wherein the radial range of the thread structure (2) measured from the outer surface of the elongated element (1) has a first value in the first part of the structure and a second value in the second part of the structure, and the second value is different from the first value such that the first part has different flexibility from the second part.

14. The screw thread structure (2) is freely wrapped around the elongated element (1), The apparatus according to claim 10 or 11, characterized in that the distal end of the thread structure (2) is fixed to the elongated element (1), and the proximal end of the thread structure (2) is detachably fixed to the elongated element (1), and the thread pitch (112) is changed by displacing the proximal end in the longitudinal direction to the proximal or distal side.

15. The screw thread structure (2) can be freely wrapped around the elongated element (1), The apparatus according to claim 10 or 11, characterized in that the elongated element (1) is provided with a locking means that, in a first rotational direction of the elongated element (1), engages with the threaded structure (2) to transmit the rotational motion of the elongated element (1) to the threaded structure (2), and in a second rotational direction opposite to the first rotational direction, disengages from the threaded structure (2) to allow the threaded structure (2) to rotate freely.

Images