Steerable instrument comprising hinge with slotted structure

Abstract

To provide a cylindrical element provided with a hinge having a slotted structure optimized for bendability.SOLUTION: A cylindrical element with a hinge structure has: a first portion 524; 522(n-1); a second portion 522(1); 522(n) which is rotatable relative to the first portion, about two rotation sections 530(1); 530(n) arranged at locations rotated 180° relative to each other viewed in a tangential direction of the cylindrical element; and an attachment element. The rotation sections are implemented by being provided with an opening accommodating a pin, being attached to a portion of the attachment element and being attached to another portion of the attachment element, such that the first portion and the second portion cannot move relative to each other in a longitudinal direction, tangential direction, or radial direction but are configured to rotate relative to each other about a center of rotation.SELECTED DRAWING: Figure 9c

Description

[Technical field]

[0001]

[0001] The present invention relates to a steerable instrument for endoscopic and / or invasive applications such as in surgery. The steerable instrument according to the present invention can be used in both medical and non-medical applications. Examples of the latter include inspection and / or repair of mechanical and / or electronic hardware in hard to reach locations. Therefore, the terms used in the following description, such as endoscopic applications or invasive instrument, should be interpreted broadly. [Background technology]

[0002]

[0002] The shift from surgical interventions that require large incisions to expose the target area to minimally invasive surgical interventions, i.e., surgical interventions that require only natural orifices or small incisions to establish access to the target area, is a well-known and ongoing process. When performing minimally invasive surgical interventions, an operator, such as a physician, needs an access device that is configured to insert and guide an invasive instrument into the human or animal body through an access port in the body. To reduce scar tissue formation and pain to the human or animal patient, the access port is preferably provided by a single small incision in the skin and subcutaneous tissue. From this point on, the possibility of using natural orifices in the body is even higher. Furthermore, the access device preferably allows the operator to control one or more degrees of freedom that the invasive instrument provides. In this way, the operator can ergonomically and precisely perform the necessary measures in the target area in the human or animal body while reducing the risk of collision of the instrument used.

[0003]

[0003] Surgical invasive instruments and endoscopes through which these instruments are guided towards a target area are well known in the art. Both the invasive instruments and endoscopes may comprise steerable tubes that enhance their navigation and steering capabilities. Such steerable tubes preferably comprise a proximal end portion including at least one flexible zone, a distal end portion including at least one flexible zone, and a rigid or flexible intermediate portion, and the steerable tubes further comprise a steering arrangement adapted to convert a deflection of at least a portion of the proximal end portion relative to the rigid intermediate portion into an associated deflection of at least a portion of the distal end portion.

[0004]

[0004] Furthermore, the steerable tube preferably comprises several coaxially arranged cylindrical elements, including an outer element, an inner element and one or more intermediate elements, depending on the number of flexibility zones at the proximal and distal ends of the tube and the desired realization of the steering members of the steering arrangement, i.e., whether all steering members can be arranged in a single intermediate element or whether the steering members are divided into different sets, each set of steering members being arranged in a different intermediate member. Furthermore, the steering members can be divided into sub-parts arranged in different intermediate members. In most of the prior art devices, the steering arrangement comprises as steering members conventional steering cables, for example with a diameter of 1 mm or less, which are arranged between the associated flexibility zones at the proximal and distal ends of the tube. However, steering cables may have drawbacks in certain applications. Therefore, it may be preferable to avoid them and realize the steering members by one or more sets of longitudinal elements forming an integral part of the one or more intermediate elements. Each of the intermediate elements can be manufactured by using a suitable material addition technique such as injection molding or plating, or by starting with a cylindrical element and then using a suitable material removal technique such as laser cutting, photochemical etching, deep pressing, traditional chipping techniques such as drilling or milling, or a high-pressure water jet cutting system. Of the above-mentioned material removal techniques, laser cutting is very advantageous since it allows very precise and clean removal of material under reasonable economic conditions. Further details regarding the design and manufacture of the above-mentioned steerable tube and its steering structure are described, for example, in WO2009 / 112060A1, WO2009 / 127236A1, US13 / 160,949, and US13 / 548,935 by the applicant, all of which are incorporated herein by reference in their entirety. The hinge of the present invention is applicable to all structures described in these patent documents. Moreover, the hinge of the present invention is equally applicable to devices with "classical" cables or wires.

[0005]

[0005] Steerable invasive instruments typically include a handle disposed at the proximal end of the steerable tube for steering the tube and / or manipulating an instrument disposed at the distal end of the steerable tube. Such an instrument may be, for example, a camera, a manual manipulator such as scissors, forceps, or a manipulator using an energy source such as an electrical, ultrasonic, or light energy source. The instrument may be a catheter.

[0006]

[0006] In this application, the terms "proximal" and "distal" are defined relative to an operator, e.g., a physician operating an instrument or endoscope. For example, the proximal end should be interpreted as the portion located closer to the physician, and the distal end should be interpreted as the portion located further away from the physician.

[0007]

[0007] In these steerable instruments, the longitudinal elements (or steering wires or cables) need to be flexible in at least parts of the instrument to allow bending relative to the longitudinal axis of the instrument at both the proximal and distal ends. These longitudinal elements are often located between adjacent outer and inner cylindrical elements. When bending these flexible zones of the instrument, in each similar zone, these longitudinal elements bend together with the bendable portions of the outer and inner cylindrical elements.

[0008]

[0008] The bendable zone in the cylindrical element can be realized by a hinge manufactured as a slotted structure in the cylindrical element. Such slots can be made by laser cutting or water cutting the cylindrical element. There is a continuous desire to optimize such hinges with respect to flexibility (i.e. bending ability), resistance to elasticity in the longitudinal direction of the cylindrical element (longitudinal stiffness), and resistance to elasticity in the tangential direction of the cylindrical element (tangential stiffness). There is a particular need for a hinge that gives the cylindrical element a bending ability of more than 90° along the shortest possible longitudinal portion of the cylindrical element without the hinge going out of its elastic range. More specific background regarding hinges is as follows.

[0009]

[0009] In the steerable devices described in WO2009 / 112060 and WO2009 / 127236, the flexible sections in the inner and outer layers need some kind of hinge and / or elastic structure to provide bending of these sections. Preferably, bending of these sections requires minimal force and has minimal friction, but the flexible sections should have sufficient longitudinal and torsional (rotational) strength to provide robust handling and operation performance. Another requirement is that after manufacturing the necessary geometric shapes and features of these layers, the processed tube should still be integral and straight for further handling, alignment, and device assembly steps.

[0010]

[0010] The hinge can be formed by small elements of material that can be easily bent by elastic deformation and keep the processed tube integral and straight, as shown, for example, in WO2009 / 112060, WO2009 / 127236, and WO2018 / 067004. A drawback of these types of hinges is that the bending ability is limited because it is desired to keep the deformation of the hinge elements elastic rather than plastic. Plastic deformation can result in a very short fatigue life of the hinge, in which case the structural integrity of the device can be maintained only for a small number of deflections of the bendable zone. Another drawback is that a relatively large force is required to elastically bend the material of the hinge, and a strong pull wire must be used to prevent deflection losses due to elastic stretching of the pull wire.

[0011]

[0011] The hinges can also be formed by cutting real hinges, where the circularly shaped hinge elements can rotate freely in the corresponding recesses. To prevent the tube from breaking apart after processing, the shape of this hinge must be such that the circular elements are surrounded by the corresponding recesses by more than 180 degrees, which provides longitudinal integrity. However, the hinges can still separate by sliding along the hinge axis itself (perpendicular to the longitudinal axis of the tube), and thus the processed tube can still break apart into separate parts. Also, after processing, tubes with these hinges do not remain straight after processing, but are very flexible and easily bent. This makes further handling, alignment and equipment assembly difficult. These hinges are illustrated, for example, in FIG. 5A of the non-prepublished Dutch patent application NL2021823. To prevent the tube from being flexible after processing and the separation of the parts along the hinge axis, these hinges can incorporate very small elastic bridges that can be easily bent, as explained in NL2021823, figures 16B and 18. Also, such hinges can be applied with removable fixtures to keep the tubes together and straight after processing, as explained in WO2016089202. This combination of a "true" hinge combined with a removable fixture is shown in NL2021823, figure 16A. The main drawback of this "true" hinge is that the geometry of the hinge itself strongly limits the deflection when one wants to keep the overall size of the hinge structure within acceptable limits, as can be seen in NL2021823, figure 10. Another drawback when combined with elastically deformable elements is the increased bending forces.

[0012]

[0012] WO2008 / 139768A1, US2009 / 0124857A1, WO2004 / 103430A2, and US2006 / 0199999A1 describe devices in which multiple cylindrical sections are arranged along a cylindrical axis to form a cylindrical element. The hinge is realized by ears or similar structures at the ends of the cylindrical sections, which are arranged such that the ears or similar structures overlap radially, so that a pin can be inserted into the opening of the ears to form the hinge. However, these arrangements do not meet the requirements mentioned herein above, namely that the processed tube should remain integral and straight for further handling, alignment, and device assembly steps. Furthermore, these arrangements require multiple individual cylindrical sections to be brought together and aligned to assemble a single cylindrical or tubular element, leading to a complex assembly procedure. Also, after assembly, these hinged tubes do not stay straight but are very flexible and bend easily, making further handling and equipment assembly difficult, including coaxial alignment with additional tubular elements. Summary of the Invention

[0013]

[0013] It is an object of the present invention to provide a cylindrical element with a hinge having a slotted structure optimized with respect to bending, and in one embodiment, a steerable instrument for endoscopic and / or invasive applications provided with such a hinge.

[0014]

[0014] This is achieved by a cylindrical element as claimed in claim 1.

[0015]

[0015] The cylindrical element can be manufactured by the method according to the independent method claim.

[0016]

[0016] Embodiments of the invention are set out in the dependent claims.

[0017]

[0017] The cylindrical element with hinges according to the claims improves bending properties. The claimed device has a strong "true" hinge, which allows high deflections since the several parts can rotate freely relative to each other, and has neither fatigue life limitations nor high bending forces.

[0018]

[0018] It will be appreciated that the present invention will now be described in detail with reference to "cylindrical" elements. However, it will be understood that "cylindrical" is not limited to circular cross sections only. Any other suitable cross sections may be applied, including elliptical, rectangular, etc.

[0019]

[0019] Further features and advantages of the present invention will become apparent from the description of the present invention by non-limiting and non-exclusive embodiments. These embodiments should not be interpreted as limiting the scope of protection. Those skilled in the art will understand that other alternatives and equivalent embodiments of the present invention can be conceived and implemented without departing from the scope of the present invention. The embodiments of the present invention will be described with reference to the figures in the accompanying drawings, in which similar or identical reference symbols indicate similar, identical or corresponding parts. [Brief description of the drawings]

[0020] [Figure 1]

[0020] A schematic perspective view of an invasive instrument assembly having two steerable instruments is shown. [Figure 2a]

[0021] FIG. 1 illustrates a side view of a non-limiting embodiment of a steerable invasive device. [Figure 2b]

[0022] 1 provides a detailed perspective view of a non-limiting embodiment of an elongated tubular body of a steerable instrument. [Figure 2c]

[0023] 2b provides a more detailed view of the distal end of the elongated tubular body shown in FIG. 2b. [Figure 2d]

[0024] 2b shows a longitudinal cross-section of the elongated tubular body of the steerable instrument shown in FIG. 2b. [Figure 2e]

[0025] FIG. 2c shows a longitudinal cross-sectional view of the elongated tubular body of the steerable instrument shown in FIG. 2b, with the first proximal flexibility zone and the first distal flexibility zone bent, illustrating the operation of the steering arrangement. [Figure 2f]

[0026] FIG. 2c shows a longitudinal cross-sectional view of the elongated tubular body of the steerable instrument shown in FIG. 2e, in which the second proximal flexibility zone and the second distal flexibility zone are additionally bent, further illustrating the operation of the steering arrangement. [Figure 2g]

[0027] 1 illustrates a longitudinal cross-sectional view of an exemplary embodiment of a steerable instrument having one proximal and one distal flexibility zone. [Figure 2h]

[0028] FIG. 2c shows a perspective exploded view of three cylindrical elements of the steerable instrument shown in FIG. 2g. [Figure 2i]

[0029] 2h shows a top view of an exemplary embodiment of an intermediate cylindrical element of a steerable instrument shown in FIG. 2h in an unfolded form. The intermediate cylindrical element can be formed by rolling the unfolded form into a cylindrical configuration and attaching adjacent sides of the rolled configuration by any known attachment means, such as welding techniques. [Diagram 3]

[0030] 2b shows a perspective view of a portion of the elongated tubular body shown in FIG. 2 with the outer cylindrical element partially removed to show an exemplary embodiment of a longitudinal steering element obtained after providing a longitudinal slit in the wall of an intermediate cylindrical element interconnecting a first proximal flexibility zone and a first distal flexibility zone of the elongated tubular body. [Figure 4]

[0031] FIG. 2 shows a 3D view of an exemplary embodiment of the present invention. [Figure 5a]

[0032] 1 illustrates a hinge structure according to one embodiment of the present invention. [Figure 5b] 1 illustrates a hinge structure according to one embodiment of the present invention. [Figure 5c] 1 illustrates a hinge structure according to one embodiment of the present invention. [Figure 5d] 1 illustrates a hinge structure according to one embodiment of the present invention. [Figure 6]

[0033] 1 shows a schematic cross-sectional view of a portion of a hinge structure according to one embodiment. [Figure 7]

[0034] 13 shows a schematic cross-sectional view of a portion of a hinge structure according to a further example. [Figure 8a]

[0035] 1 shows a hinge structure according to another embodiment of the present invention. [Figure 8b] 1 shows a hinge structure according to another embodiment of the present invention. [Figure 8c] 1 shows a hinge structure according to another embodiment of the present invention. [Figure 9a]

[0036] 1 shows a hinge structure according to another embodiment of the present invention. [Figure 9b] 1 shows a hinge structure according to another embodiment of the present invention. [Figure 9c] 1 shows a hinge structure according to another embodiment of the present invention. [Figure 10a]

[0037] 9b shows a hinge structure which can be combined with the structure of FIG. 9a to form another embodiment of the present invention. [Figure 10b] 9b shows a hinge structure which can be combined with the structure of FIG. 9a to form another embodiment of the present invention. [Figure 11]

[0038] 1 shows a hinge structure according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021]

[0039] Figure 2a shows a non-limiting embodiment of a steerable invasive device 10. Figure 1 shows a non-limiting embodiment of an invasive device assembly 1 having an introducer with two such steerable invasive devices 10. Details of the steerable invasive device 10 are described in connection with Figures 2b-2j.

[0022]

[0040] FIG. 2a shows a side view of a steerable invasive device 10. The steerable device 10 comprises an elongated tubular body 18 having a proximal end 11 with two actuating flexibility zones 14, 15, a distal end 13 with two distal flexibility zones 16, 17, and an intermediate section 12. Here, the intermediate section 12 is shown as being rigid. However, in certain applications, as will be explained in more detail below, the intermediate section 12 may be flexible. The actuating flexibility zones 14, 15 in this embodiment are configured as flexible proximal zones, and are further referred to as flexible proximal zones. These flexible proximal zones 14, 15 are connected to the distal flexibility zones by suitable longitudinal elements (not shown in FIG. 2a). Alternatively, the flexible proximal zones may be connected to the distal flexibility zones by steering cables, as known in the prior art. As will be described in more detail below, bending one such proximal flexibility zone 14, 15, respectively, causes the corresponding flexible distal zone to also bend.

[0023]

[0041] As mentioned above, the intermediate section 12 may be flexible. This may be achieved by one or more bendable zones. However, these bendable zones are merely flexible and their bending is not controlled by another bendable zone. If desired, more than two steerable flexible distal zones may be provided. At the distal end 13, an instrument such as a forceps 2 is disposed. At the proximal end 11, a handle 3 is disposed, which is adapted, for example, to open and close the jaws of the forceps 2, for example via a suitable actuation cable (not shown) disposed within the instrument. Cable arrangements for doing so are well known in the art. Other instruments may be provided at the distal end, as known to those skilled in the art.

[0024]

[0042] 2b provides a detailed perspective view of a distal portion of elongated tubular body 18 of steerable instrument 10, showing that elongated tubular body 18 comprises several coaxially arranged layers or cylindrical elements, including outer cylindrical element 104 that terminates after first distal flexibility zone 16 at distal end portion 13. Distal end portion 13 of outer cylindrical element 104 is fixedly attached to adjacent cylindrical element 103 located inside outer cylindrical element 104, for example by spot welding at weld spot 100. However, any other suitable attachment method can be used, including any mechanical snap-fit ​​connection or bonding with a suitable adhesive.

[0025]

[0043] FIG. 2c provides a more detailed view of the distal end 13, showing that in this embodiment, the distal end 13 includes three coaxially arranged layers or cylindrical elements: an inner cylindrical element 101, a first intermediate cylindrical element 102, and a second intermediate cylindrical element 103. The distal ends of the inner cylindrical element 101, the first intermediate cylindrical element 102, and the second intermediate cylindrical element 103 are all three fixedly attached to one another. This can be done by spot welding at weld spots 100. However, any other suitable attachment method can be used, including any mechanical snap-fit ​​connection or gluing with a suitable adhesive. The attachment points can be at the edges of the inner cylindrical element 101, the first intermediate cylindrical element 102, and the second intermediate cylindrical element 103, as shown. However, these attachment points can also be located some distance from these edges, preferably between the edges and the location of the flexibility zone 17.

[0026]

[0044] It will be clear to a person skilled in the art that the elongated tubular body 18 shown in Fig. 2b comprises a total of four cylindrical elements. The elongated tubular body 18 according to the embodiment shown in Fig. 2b comprises two intermediate cylindrical elements 102 and 103 in which the steering members of the steering arrangement are arranged.

[0027]

[0045] The steering arrangement in the exemplary embodiment of the elongated tubular body 18 shown in Figure 2b comprises two flexibility zones 14, 15 at the proximal end 11 of the elongated tubular body 18, two flexibility zones 16, 17 at the distal end 13 of the elongated tubular body 18, and a steering member disposed between the associated flexibility zones at the proximal end 11 and the distal end 13. An exemplary actual arrangement of the steering members is shown in Figure 2d, which provides a schematic longitudinal cross-sectional view of the exemplary embodiment of the elongated tubular body 18 shown in Figure 2b.

[0028]

[0046] FIG. 2 d shows a cross section of the four layers or cylindrical elements mentioned above, namely the inner cylindrical element 101 , the first intermediate cylindrical element 102 , the second intermediate cylindrical element 103 and the outer cylindrical element 104 .

[0029]

[0047] The inner cylindrical element 101, when viewed along its entire length from the distal end to the proximal end of the instrument, comprises a rigid ring 111 disposed at the distal end 13 of the steerable instrument 10, a first flexible portion 112, a first intermediate rigid portion 113, a second flexible portion 114, a second intermediate rigid portion 115, a third flexible portion 116, a third intermediate rigid portion 117, a fourth flexible portion 118, and a rigid end portion 119 disposed at the proximal end portion 11 of the steerable instrument 10.

[0030]

[0048] The first intermediate cylindrical element 102, when viewed along its entire length from the distal to the proximal end of the device, comprises a rigid ring 121, a first flexible portion 122, a first intermediate rigid portion 123, a second flexible portion 124, a second intermediate rigid portion 125, a third flexible portion 126, a third intermediate rigid portion 127, a fourth flexible portion 128, and a rigid end portion 129. The portions 122, 123, 124, 125, 126, 127, and 128 together form a longitudinal element 120 that can be moved longitudinally, like a wire. The longitudinal dimensions of the rigid ring 121, the first flexible portion 122, the first intermediate rigid portion 123, the second flexible portion 124, the second intermediate rigid portion 125, the third flexible portion 126, the third intermediate rigid portion 127, the fourth flexible portion 128, and the rigid end portion 129 of the first intermediate element 102 are aligned with, and preferably approximately equal to, and also coincident with, the longitudinal dimensions of the rigid ring 111, the first flexible portion 112, the first intermediate rigid portion 113, the second flexible portion 114, the second intermediate rigid portion 115, the third flexible portion 116, the third intermediate rigid portion 117, the fourth flexible portion 118, and the rigid end portion 119 of the inner cylindrical element 101, respectively. In this description, "approximately equal" means that each identical dimension is equal to within a limit of less than 10%, preferably less than 5%.

[0031]

[0049] Similarly, the first intermediate cylindrical element 102 comprises one or more other longitudinal elements, one of which is indicated with reference numeral 120a.

[0032]

[0050] The second intermediate cylindrical element 103, as viewed along its entire length from the distal to the proximal end of the device, comprises a first rigid ring 131, a first flexible portion 132, a second rigid ring 133, a second flexible portion 134, a first intermediate rigid portion 135, a first intermediate flexible portion 136, a second intermediate rigid portion 137, a second intermediate flexible portion 138, and a rigid end portion 139. Portions 133, 134, 135, and 136 together form a longitudinal element 130 that can be moved longitudinally, like a wire. The longitudinal dimensions of the first rigid ring 131, the first flexible portion 132 as well as the second rigid ring 133 and the second flexible portion 134, the first intermediate rigid portion 135, the first intermediate flexible portion 136, the second intermediate rigid portion 137, the second intermediate flexible portion 138, and the rigid end portion 139 of the second intermediate cylinder 103 are aligned with, and preferably approximately equal to, and also coincident with, the longitudinal dimensions of the rigid ring 111, the first flexible portion 112, the first intermediate rigid portion 113, the second flexible portion 114, the second intermediate rigid portion 115, the third flexible portion 116, the third intermediate rigid portion 117, the fourth flexible portion 118, and the rigid end portion 119 of the first intermediate element 102, respectively.

[0033]

[0051] Similarly, the second intermediate cylindrical element 103 comprises one or more other longitudinal elements, one of which is indicated with the reference numeral 130a.

[0034]

[0052] The outer cylindrical element 104 comprises, as viewed along its entire length from the distal end to the proximal end of the device, a first rigid ring 141, a first flexible portion 142, a first intermediate rigid portion 143, a second flexible portion 144, and a second rigid ring 145. The longitudinal dimensions of the first flexible portion 142, the first intermediate rigid portion 143, and the second flexible portion 144 of the outer cylindrical element 104 are aligned with, and preferably approximately equal to, and also coincident with, the longitudinal dimensions of the second flexible portion 134, the first intermediate rigid portion 135, and the first intermediate flexible portion 136 of the second intermediate element 103, respectively. The rigid ring 141 has approximately the same length as the rigid ring 133 and is fixedly attached to the rigid ring 133, for example by spot welding or gluing. Preferably, the rigid ring 145 overlaps the second intermediate rigid portion 137 only for a length necessary to provide a suitable fixed attachment between the rigid ring 145 and the second intermediate rigid portion 137, respectively, for example by spot welding or gluing. The rigid rings 111, 121, and 131 are attached to one another, for example by spot welding or gluing, either at their edges or at a distance from these edges.

[0035]

[0053] In one embodiment, the same may apply to the rigid end portions 119, 129, and 139, which may also be attached together in an equivalent manner. However, the structure may be such that the diameter of the cylindrical element in the proximal portion is larger or smaller than the diameter in the distal portion. In such an embodiment, the structure in the proximal portion differs from that shown in FIG. 2d. As a result of the increase or decrease in diameter, an amplification or attenuation is achieved, i.e. the bending angle of the flexible zone in the distal portion is larger or smaller than the bending angle of the corresponding flexible portion in the proximal portion.

[0036]

[0054] The inner and outer diameters of the cylindrical elements 101, 102, 103, and 104 are selected such that, at the same location along the elongated tubular body 18, the outer diameter of the inner cylindrical element 101 is slightly smaller than the inner diameter of the first intermediate cylindrical element 102, which is slightly smaller than the inner diameter of the second intermediate cylindrical element 103, which is slightly smaller than the inner diameter of the outer cylindrical element 104, thereby allowing adjacent cylindrical elements to slide relative to each other. The dimensioning should allow a slip fit between adjacent elements. The gap between adjacent elements may generally be on the order of 0.02 to 0.1 mm, but depends on the particular application and materials used. The gap is preferably smaller than the wall thickness of the longitudinal elements to prevent an overlapping configuration of the longitudinal elements. Limiting the gap to about 30%-40% of the wall thickness of the longitudinal elements is generally sufficient.

[0037]

[0055] As can be seen in Fig. 2d, the flexible zone 14 of the proximal end 11 is connected to the flexible zone 16 of the distal end 13 by the portions 134, 135 and 136 of the second intermediate cylindrical element 103 forming a first set of longitudinal steering members of the steering arrangement of the steerable device 10. Furthermore, the flexible zone 15 of the proximal end 11 is connected to the flexible zone 17 of the distal end 13 by the portions 122, 123, 124, 125, 126, 127 and 128 of the first intermediate cylindrical element 102 forming a second set of longitudinal steering members of the steering arrangement. Using the above described structure, it is possible to use the steerable device 10 in double bending. The principle of operation of this structure is explained in relation to the example shown in Fig. 2e and Fig. 2f.

[0038]

[0056] For convenience, as shown in Figures 2d, 2e and 2f, the various portions of cylindrical elements 101, 102, 103 and 104 are grouped into zones 151 to 160, which are defined as follows: Zone 151 comprises rigid rings 111, 121 and 131; Zone 152 comprises portions 112, 122 and 132; Zone 153 comprises rigid rings 133 and 141 and portions 113 and 123; Zone 154 comprises portions 114, 124, 134 and 142; Zone 155 comprises portions 115, 125, 135 and 143; Zone 156 comprises portions 116, 126, 136 and 144; Zone 157 comprises rigid ring 145 and portions 117, 127 and 137 which coincide therewith. Zone 158 comprises portions 117, 127, and 137 outside of zone 157. Zone 159 comprises portions 118, 128, and 138. Finally, zone 160 comprises rigid end portions 119, 129, and 139.

[0039]

[0057] A bending force can be applied in any radial direction to zone 158 to deflect at least a portion of the distal end 13 of the steerable device 10. According to the example shown in Figures 2e and 2f, zone 158 is bent downwards relative to zone 155. As a result, zone 156 is bent downwards. Due to the first set of steering members comprising portions 134, 135 and 136 of the second intermediate cylindrical element 103 arranged between the second intermediate rigid portion 137 and the second rigid ring 133, the downward bending of zone 156 is translated into an upward bending of zone 154 relative to zone 155 by a longitudinal displacement of the first set of steering members. This is shown in both Figures 2e and 2f.

[0040]

[0058] Note that the exemplary downward bending of zone 156 results in an upward bending of only zone 154 at the distal end of the device, as shown in FIG. 2e. The bending of zone 152 as a result of bending of zone 156 is prevented by zone 153, which is disposed between zones 152 and 154. Any radial bending force is then applied to zone 160, which also bends zone 159. As shown in FIG. 2f, zone 160 is bent upward relative to its position shown in FIG. 2e. As a result, zone 159 bends upward. With the second set of steering members, comprising portions 122, 123, 124, 125, 126, 127, and 128 of the first intermediate cylindrical element 102 disposed between the rigid ring 121 and the rigid end portion 129, the upward bending of zone 159 is translated into a downward bending of zone 152 relative to its position shown in FIG. 2e by the longitudinal displacement of the second set of steering members.

[0041]

[0059] FIG. 2f further illustrates that the initial bending of the device in zone 154 shown in FIG. 2e is maintained because, as described above, this bending is governed only by the bending of zone 156, and the bending of zone 152 is governed only by the bending of zone 159. The ability of zones 152 and 154 to bend independently of one another allows the distal end 13 of the steerable device 10 to be given an independent position and longitudinal orientation. In particular, the distal end 13 can assume an advantageous S-shape. Those skilled in the art will appreciate that the ability to bend zones 152 and 154 independently of one another significantly enhances the maneuverability of the distal end 13, and thus the entire steerable device 10.

[0042]

[0060] It is clear that the length of the flexible portions shown in Figures 2d-2f can be varied to accommodate specific requirements related to the bending radius and overall length of the distal and proximal ends 13, 11 of the steerable device 10, or to accommodate the gain or loss ratio between at least a portion of the bending of the proximal end 11 and at least a portion of the bending of the distal end 13.

[0043]

[0061] The steering member comprises one or more sets of longitudinal elements forming an integral part of one or more of the intermediate cylindrical elements 102, 103. Preferably, the longitudinal elements comprise the remaining part of the wall of the intermediate cylindrical element 102, 103 after providing a longitudinal slit in the wall of the intermediate cylindrical element 102, 103, which longitudinal slit defines the remaining longitudinal steering element.

[0044]

[0062] Further details regarding the manufacture of the latter longitudinal steering elements are provided with reference to Figures 2g to 2i, which relate to an exemplary embodiment of a steerable instrument having only one flexibility zone at both its proximal end 11 and distal end 13.

[0045]

[0063] 2g shows a longitudinal cross section of a steerable device 2201 comprising three coaxially arranged cylindrical elements: an inner cylindrical element 2202, a middle cylindrical element 2203, and an outer cylindrical element 2204. Suitable materials to be used to fabricate the cylindrical elements 2202, 2203, and 2204 include stainless steel, cobalt chrome, shape memory alloys such as Nitinol®, plastics, polymers, composites, or other cuttable materials. Alternatively, the cylindrical elements can be fabricated by a 3D printing process.

[0046]

[0064] The inner cylindrical element 2202 has a first rigid end 2221 located at the distal end 13 of the device 2201, a first flexible portion 2222, an intermediate rigid portion 2223, a second flexible portion 2224, and a second rigid end 2225 located at the proximal end 11 of the device 2201.

[0047]

[0065] The outer cylindrical element 2204 also comprises a first rigid end 2241, a first flexible section 2242, an intermediate rigid section 2243, a second flexible section 2244, and a second rigid end 2245. The lengths of each of the sections 2221, 2222, 2223, 2224, and 2225 of the cylindrical element 2202 and the lengths of each of the sections 2241, 2242, 2243, 2244, and 2245 of the cylindrical element 2204 are preferably substantially the same such that when the inner cylindrical element 2202 is inserted into the outer cylindrical element 2204, these different respective sections are longitudinally aligned with one another.

[0048]

[0066] The intermediate cylindrical element 2203 also has a first rigid end 2331 and a second rigid end 2335 which, in the assembled state, are located between corresponding rigid portions 2221, 2241 and 2225, 2245, respectively, of the two other cylindrical elements 2202, 2204. The intermediate portion 2333 of the intermediate cylindrical element 2203 comprises three or more separate longitudinal elements which may have different forms and shapes, as will be explained below. After assembling the three cylindrical elements 2202, 2203, and 2204, inserting element 2202 into element 2203, and inserting the two combined elements 2202, 2203 into element 2204, at least the first rigid end 2221 of the inner cylindrical element 2202, the first rigid end 2331 of the middle cylindrical element 2203, and the first rigid end 2241 of the outer cylindrical element 2204 are attached to each other at the distal end of the device. In the embodiment shown in Figures 2g and 2h, the second rigid end 2225 of the inner cylindrical element 2202, the second rigid end 2335 of the middle cylindrical element 2203, and the second rigid end 2245 of the outer cylindrical element 2204 are also attached to each other at the proximal end of the device, such that the three cylindrical elements 2202, 2203, 2204 form one integral unit.

[0049]

[0067] In the embodiment shown in Fig. 2h, the intermediate part 2333 of the intermediate cylindrical element 2203 comprises several longitudinal elements 2338 with the same cross section, so that the intermediate part 2333 has the overall shape and form as shown in Fig. 2i in the unfolded state of the intermediate cylindrical element 2203. From Fig. 2i it also becomes clear that the intermediate part 2333 is formed by several of the parallel longitudinal elements 2338 equally spaced apart over the circumference of the intermediate cylindrical part 2203. Advantageously, the number of longitudinal elements 2338 is at least three so that the device 2201 is fully controllable in any direction, although any higher number is also possible. Preferably, the number of longitudinal elements 2338 is six or eight.

[0050]

[0068] Fabrication of such an intermediate section is most conveniently done by injection molding or plating techniques, or by starting with a cylindrical tube having the desired inner and outer diameters and removing the portions of the cylindrical tube's wall that are necessary to ultimately arrive at the desired shape of the intermediate cylindrical element 2203. However, alternatively, any 3D printing method can be used.

[0051]

[0069] The removal of material can be done by various techniques such as laser cutting, photochemical etching, deep pressing, conventional chipping techniques such as drilling or milling, high pressure water jet cutting systems, or any suitable material removal process available. Preferably, laser cutting is used since it allows very precise and clean removal of material under reasonable economic conditions. The above process is a convenient method since it allows the member 2203 to be made in one process, so to speak, without the need for additional steps to connect the various parts of the intermediate cylindrical element, as is required in conventional devices where conventional steering cables must be connected to the ends in some way. The same type of technology can be used to fabricate the inner cylindrical element 2202 and the outer cylindrical element 2204 with their respective flexible parts 2222, 2224, 2242, and 2244.

[0052]

[0070] FIG. 3 shows an exemplary embodiment of the longitudinal (steering) element 4 obtained after providing a longitudinal slit 5 in the wall of the second intermediate cylindrical element 103 interconnecting the proximal flexibility zone 14 and the distal flexibility zone 16 as described above. That is, the longitudinal steering element 4 is at least partially spiraled about the longitudinal axis of the instrument, so that the end portion of each steering element 4 in the proximal part of the instrument is arranged in a different angular orientation about the longitudinal axis than the end portion of the same longitudinal steering element 4 in the distal part of the instrument. If the longitudinal steering elements 4 were arranged in a linear orientation, bending of the instrument in the proximal part in one plane would result in bending of the instrument in the distal part in the same plane but in the opposite direction by 180 degrees. This spiral structure of the longitudinal steering element 4 allows the effect that bending of the instrument in the proximal part in one plane can result in bending of the instrument in the distal part in another plane or in the same direction in the same plane. A preferred helical configuration is such that the end portion of each steering element 4 at the proximal portion of the instrument is arranged in an angularly offset orientation of 180 degrees about the longitudinal axis relative to the end portion of the same longitudinal steering element 4 at the distal portion of the instrument. However, any other angularly offset orientation, e.g., 90 degrees, is within the scope of this document. The slits are dimensioned such that when placed in place on the steerable instrument, the movement of the longitudinal elements is guided by the adjacent longitudinal elements.

[0053]

[0071] The flexible portions 112, 132, 114, 142, 116, 144, 118 and 138 shown in Figure 2d and the flexible portions 2222, 2224, 2242 and 2244 shown in Figures 2g and 2h can be obtained by the method described in European Patent Application No. 08004373.0 filed on March 10, 2008 (page 5, lines 15-26), although any other suitable process can be used to make the flexible portions.

[0054]

[0072] Such a flexible section may have a structure as shown in Figures 2b and 2c. That is, flexibility may be obtained by a plurality of slits 14a, 15a, 16a, 17a. For example, two circumferential slits may be provided in the cylindrical element along the same circumferential line, both slits being located at a distance from each other. A plurality of identical sets of circumferential slits 14a, 15a, 16a, 17a may be provided at a plurality of distances in the longitudinal direction of the device, with successive sets being located at angularly rotated positions, for example at 90 degrees each time. In such an arrangement, all parts of the cylindrical element are still connected to each other.

[0055]

[0073] Furthermore, as shown in Fig. 2d, the above-mentioned manufacturing method can be used if the portions 122, 123, 124, 125, 126, 127 and 128 of the first intermediate cylindrical element 102 and the portions 134, 135 and 136 of the second intermediate cylindrical element 103 forming respectively the first and second sets of longitudinal steering members are realized as longitudinal steering elements 4 as shown in Fig. 2h. The same applies for the longitudinal elements 2338 of Fig. 2h and Fig. 2i. Furthermore, any of the embodiments described in EP 2 762 058 A can be used according to the present invention.

[0056]

[0074] Otherwise, the longitudinal elements 4, 2338 may be obtained by any other technique known in the art, for example as described in EP 1 708 609 A. The only restriction on the structure of the longitudinal elements used in these sections is that the overall flexibility of the device must be maintained at the locations where the flexible sections meet.

[0057]

[0075] The different coaxially arranged layers or cylindrical elements 101, 102, 103, 104, 2202, 2203 and 2204 as described above with respect to the exemplary embodiment of the steerable instrument shown in Figures 2d, 2e and 2f, respectively, can be manufactured by any of the known methods, provided that they are suitable for making a multi-layer system. A multi-layer system should be understood to be a steerable instrument comprising at least two separate sets of longitudinal elements 4, 2338 for transmitting the movement of the proximal end to the distal end. The assembly of different cylindrical elements can be realized in the same way. A preferred method for manufacturing the different cylindrical elements is described in the above-mentioned EP2762058A, which application is incorporated herein by reference in its entirety.

[0058]

[0076] In the above embodiment, the proximal and distal portions are similarly constructed, however, as will become apparent below, this does not necessarily have to be the case.

[0059]

[0077] FIG. 4 shows a 3D view of an example of a steerable instrument. Similar reference numbers refer to the same elements in the other figures. Their description will not be repeated here. The instrument comprises five coaxial cylindrical elements 202-210. The inner cylindrical element 210 is surrounded by an intermediate cylindrical element 208, which is surrounded by an intermediate cylindrical element 206, which is surrounded by an intermediate cylindrical element 204, which is finally surrounded by an outer cylindrical element 202. The inner intermediate cylindrical element may be made of a flexible spiral spring. The proximal and distal ends of the instrument are respectively indicated by reference numbers 226 and 227.

[0060]

[0078] As shown here, the device 18 comprises a flexibility zone 19 in its intermediate part between the flexibility zones 14 and 16. That is, the intermediate cylindrical element 204 (located on the outer surface of the area of ​​the flexibility zone 19) is provided with a slotted structure to give the intermediate cylindrical element a desired flexibility. The longitudinal length of the slotted structure in the flexibility zone 19 depends on the desired application. It may be as long as the entire part between the flexibility zones 14 and 16. All other cylindrical elements 206, 208, 210 inside the intermediate cylindrical element 204 are also flexible in the flexibility zone 19. Those cylindrical elements having a longitudinal element within the flexibility zone 19 are flexible by definition. The others are preferably provided with a suitable hinge made by a suitable slotted structure.

[0061]

[0079] According to the invention, at least one of the slotted structures has a special design as described in detail below, which may be applied at any position where the device described with reference to the figures above has a hinge.

[0062]

[0080] Figure 5a shows a cylindrical element 500 with a hinge 501 made as a slotted structure. The cylindrical element 500 comprises a portion 504 and a further portion 509 opposite the portion 504. The hinge 501 is located between them.

[0063]

[0081] Hinge 501 comprises a number of hinge portions 502(1), 502(2), ... 502(n), ... 502(N), where N is an integer greater than 1. In the illustrated example, each hinge portion 502(n) has an identical shape, although this need not be the case. Each hinge portion 502(n) is shown as a rigid ring-shaped portion of cylindrical element 500.

[0064]

[0082] Part 504 and hinge part 502(1) are rotatable relative to each other by means of two rotatable sections 507(1) (one of which is visible in FIG. 5a), which are located 180° rotated relative to each other in the tangential direction of cylindrical element 500. To that effect, ring-shaped part 502(1) is provided with two extensions 506(1) (only one of which is visible in FIG. 5a), which are arranged 180° opposite each other when viewed in the tangential direction of cylindrical element 500. That is to say, the two rotatable sections 507(1) and the associated two extensions 506(1) are located at the same position along central axis 500c (cylinder axis) and are located such that a line interconnecting the two rotatable sections and the two extensions intersects the central axis at a right angle. Each extension 506(1) has a circular outer edge oriented towards part 504. Portion 504 is provided with two notches 505(1) (only one is visible in FIG. 5a) arranged 180° opposite each other when viewed tangentially to cylindrical element 500. Each notch 505(1) has a circular inner edge of a radius equal to or slightly larger than the circular outer edge of extension 506(1) to allow extension 506(1) to rotate within notch 505(1). Each notch 505(1) accommodates one extension 506(1).

[0065]

[0083] Preferably, extension 506(1) and notch 505(1) are made by cutting a circular slot in cylindrical element 500, for example by laser cutting or water cutting. Any other cutting technique may be used instead. In one example, the cutting process is performed such that the slot is interrupted by small bridges 510(1), so that extension 506(1) and notch 505(1) are still attached to each other. These bridges act as "breaking elements" as described in detail in patent application WO2016 / 089202A1 as well as in non-prepublished patent application PCT / NL2019 / 050680. These bridges or breaking elements are made intentionally when the cylindrical elements and devices are manufactured, but are purposely made weak enough to break when forces above a certain threshold are applied to them. Here, they are designed to break when part 504 and hinge part 502(1) are rotated relative to each other about two extensions 506(1), as indicated by double arrow 503, with at least such a threshold force. The threshold force is selected such that bridges 510(1) break before either part 504 or hinge part 502(1) are deformed beyond their maximum elasticity by the applied rotational force. They only break later during the manufacturing process, as explained below. Before breaking, the breaking elements, e.g. bridges 510(1), provide a certain additional stiffness to the cylindrical element, which allows it to be more easily manipulated when inserting the cylindrical element inside another cylindrical element or when inserting another cylindrical element into it. Once broken, the breaking elements serve no further purpose, and extensions 506(1) can rotate within notches 505(1).

[0066]

[0084] Such a breaking element can be made as follows: A slot is made, for example, by directing a laser or water beam with a predefined energy and width at the cylindrical element so as to cut through the entire thickness of the cylindrical element. The laser beam is moved relative to the outer surface of the cylindrical element by moving the laser source relative to said outer surface. However, at the position where the breaking element is to be formed, the laser beam is interrupted for a certain period of time, but the laser source is still moved relative to the cylindrical element outer surface.

[0067]

[0085] As mentioned above, these breaking elements break when the various parts of the slotted structure are initially deflected relative to one another. A great advantage of such breaking elements is that after breaking, the distance between the two opposing sides of the breaking element is practically 0 μm, resulting in very little play between them.

[0068]

[0086] These types of breaking elements can be applied within the devices described herein and between any elements or portions of the cylindrical elements formed by the laser cutting process.

[0069]

[0087] The breaking elements should be designed in the following way: before breaking, each breaking element is attached to an opposing portion of the cylindrical element. These opposing portions of the cylindrical element have respective yield stress values ​​that define the force above which permanent deformation of these opposing portions occurs. Furthermore, each breaking element has a respective breaking tensile stress value that defines the force that must be applied to break the breaking element. The tensile stress value of each breaking element should be lower than the yield stress values ​​of these opposing portions of the cylindrical element. For example, the tensile stress value of each breaking element ranges from 1% to 80% of the yield stress of these portions of the cylindrical element. This range may alternatively be from 1% to 50%.

[0070]

[0088] Part 504 is provided with an outer edge 514 that faces an outer edge 512 of hinge part 502(1). Outer edge 514 and outer edge 512 define an open space therebetween so that once bridge 510(1) breaks, part 504 and hinge part 502(1) are free to rotate relative to one another about extension 506(1) up to a predetermined bend angle reached when outer edges 514 and 512 contact one another.

[0071]

[0089] The outer edges 514 and 512 result from a cut, e.g., a laser cutting or water cutting process, into the cylindrical element 500. All adjacent hinge portions 502(n), 502(n+1) have an open space therebetween, such as the space defined between portion 504 and hinge portion 502(1), which space results from a cutting process, e.g., a laser cutting or water cutting process. These spaces are alternately rotated 90° in the tangential direction of the cylindrical element 500.

[0072]

[0090] Hinge portion 502(1) has a further outer edge 515 facing outer edge 517 of hinge portion 502(2). Outer edge 515 is provided with two circular notches 505(2) (one visible in FIG. 5a) arranged 180° opposite each other when viewed tangentially of cylindrical element 500. Each circular notch 505(2) receives a circular extension 506(2) of hinge portion 502(2). Each combination of notch 505(2) and extension 506(2) is rotated 90° relative to the combination of notch 505(1) and extension 506(1). Similar to the combination of notch 505(1) and extension 506(1), the combination of notch 505(2) and extension 506(2) is made, in one example, by cutting a circular slot into cylindrical element 500, for example by a laser cutting or water cutting process. Any other cutting technique may be used instead. In one example, the cutting is done such that the slot is interrupted by small bridges 510(2) similar to bridge 510(1), so that extension 506(2) and notch 505(2) are still attached to one another. These bridges also act as "breaking elements" as described above.

[0073]

[0091] Successive pairs of rotatable sections 507(n), 507(n+1) are rotated approximately 90° relative to one another when viewed tangentially to cylindrical element 500 such that hinge portion 502(n-1) and hinge portion 502(n) can rotate relative to one another in a first direction that is perpendicular to a second direction of rotation of hinge portion 502(n) relative to hinge portion 502(n+1). As shown, the direction of rotation between successive hinge portions alternates between the first and second directions, making hinge 501 flexible in all directions.

[0074]

[0092] In one example, each notch 505(n) is still attached to the containing extension 506(n) by a bridge similar or identical to bridge 510(1) when the slot is made between the notch 505(n) and the extension 506(n). Thus, in such an example, after the cylindrical element structure 500 of FIG. 5a is made, all adjacent portions and hinge portions are still attached to each other and the structure does not break apart into separate pieces. Thus, when ready, the cylindrical element structure 500 of FIG. 5a can be inserted as an integral unit into the cylindrical element structure 520 shown in FIG. 5b. This cylindrical element 520 can also be made as an integral element with all the various portions and hinge portions still attached to each other by breakable elements before the entire hinge structure is used for bending motion.

[0075]

[0093] FIG. 5b shows cylindrical element 520 in detail.

[0076]

[0094] Figure 5b shows a cylindrical element 520 with a hinge 521 made as a slotted structure. The cylindrical element 520 comprises a portion 524 and a further portion 529 opposite the portion 524. The hinge 521 is located between them.

[0077]

[0095] Hinge 521 comprises a plurality of hinge portions 522(1), 522(2), ... 522(n), ... 522(N), where N is an integer greater than 1. In the illustrated example, each hinge portion 522(n) has an identical shape, but this need not be the case. Each hinge portion 522(n) shown is a rigid ring-shaped portion of cylindrical element 520.

[0078]

[0096] Part 524 and hinge part 522(1) are arranged to be rotatable relative to each other by two rotatable sections 530(1) (only one is visible in FIG. 5b), which are rotated 180° relative to each other when viewed tangentially to cylindrical element 521. One such rotatable section 530, indicated by the dotted circle Vd in FIG. 5b, is shown in detail in FIG. 5d. Similar to rotatable section 507(1) of cylindrical element 500 described above, the line connecting the two rotatable sections 530(1) intersects at a right angle with central axis 520c of hinge 521. Part 524 and hinge part 522(1) are therefore rotatable about this line.

[0079]

[0097] As shown in FIG. 5d, rotatable section 530(1) comprises an extension 548(1) provided with a circular outer edge. This extension 548(1) may also be referred to as a first rotating section portion. This circular extension 548(1) is received in a circular notch 550(1) of hinge portion 522(1). The circular notch may also be referred to as a second rotating section portion or may form part of the second rotating section portion, which includes the area of ​​hinge portion 522(1) facing portion 524. The radius of circular extension 548(1) and the radius of circular notch 550(1) are the same. They have the same center of rotation. Circular extension 548(1) and circular notch 550(1) are separated by a small slot made by a cutting operation, for example, laser or water cutting, or any other suitable cutting technique. During the fabrication of the slot, the slot is interrupted in place, so that extension 548(1) and notch 550(1) are still attached to each other by one or more small bridges 552(1). These bridges 552(1) act as "breaking elements" as defined above, i.e., they break when a force above a certain threshold is applied. Here, they are designed to break upon rotation of portion 524 and hinge portion 522(1) relative to each other about the two extensions 548(1) with at least such threshold force. The threshold force is selected such that bridges 552(1) break before either portion 524 or hinge portion 522(1) deforms beyond its maximum elasticity due to the applied rotational force. They only break later during the fabrication process, as explained below.

[0080]

[0098] The extension 548(1) is provided with a circular slot 542(1) about its center of rotation. The radius of the slot 542(1) is smaller than the radius of the circular extension 548(1) itself. Inside the slot 542(1), a circular island 556(1) remains. As will become clearer hereinafter, this island 556(1) forms an element that may also be called a pin or a rotatable disc in a hinge. Thus, in the context of the present invention, a pin is defined as an element that is inserted into an opening in another element about which the other element can rotate. During the manufacture of the slot 542(1), the slot 542(1) is interrupted by small bridges 540(1), by which the circular island 556(1) is still attached to the remaining part of the extension 548(1). These bridges 540(1) behave as "breaking elements" as defined above, i.e., they break when subjected to a force above a certain threshold. Here, they are designed to break when circular island 556(1) and extension 548(1) are rotated relative to one another with at least such a threshold force. The threshold force is selected so that bridge 540(1) breaks before either extension 548(1) or circular island 556(1) deforms beyond its maximum elasticity due to the applied rotational force. They only break later during the manufacturing process, as described below.

[0081]

[0099] Reference numeral 544(1) refers to an attachment structure within circular island 556(1). Attachment structure 544(1) is arranged so that circular island 556(1) can be attached to circular extension 506(1) of cylindrical element 500 after cylindrical element 500 is inserted into cylindrical element 520. Such attachment can be by any suitable attachment technique, including gluing, soldering, welding, and laser welding. To aid in laser welding, attachment structure 544(1) can be formed as a small, slotted structure in an S-shape, for example, made by a laser cutting or water cutting process.

[0082]

[0100] Hinge portion 522(1) may be provided with one or more lips 554(1) (one is shown in FIGS. 5b and 5d). Such lips 554(1) may be located adjacent rotatable section 530(1) in substantially the same tangential position as circular island 556(1). Lips 554(1) are used to attach hinge portion 522(1) of cylindrical tube 520 to hinge portion 502(1) of cylindrical element 500 after insertion of cylindrical element 500 into cylindrical element 520, for example by welding or laser welding.

[0083]

[0101] Referring again to FIG. 5b, hinge portion 522(1) and hinge portion 522(2) are arranged to be able to rotate relative to each other about two rotatable sections 530(2) (only one is shown in FIG. 5b), which are located at 180° rotation relative to each other when viewed in the tangential direction of cylindrical element 520. The structure of rotatable section 530(2) is preferably identical to rotatable section 530(1). Thus, rotatable section 530(2) preferably has the same elements as rotatable section 530(1) shown in FIG. 5d, where all indices (1) are replaced by (2). Rotatable section 530(2) is located at a position rotated 90° relative to the position of rotatable section 530(1) when viewed in the tangential direction of cylindrical element 520.

[0084]

[0102] Defined in more general terms, the rotation mechanism between two adjacent hinge portions 522(n) and 522(n+1) is as follows: the hinge portions 522(n) and 522(n+1) are arranged so that they can rotate relative to each other about two rotatable sections 530(n+1), which are located rotated 180° relative to each other when viewed in the tangential direction of the cylindrical element 520. The structure of the rotatable section 530(n+1) is preferably identical to the rotatable section 530(1). Thus, the rotatable section 530(n+1) has the same elements as the rotatable section 530(1) shown in FIG. 5d, where all indices (1) are replaced by (n+1). Rotatable section 530(n+1) is located at a position rotated 90° with respect to the positions of rotatable sections 530(n) and 530(n+2) when viewed in the tangential direction of cylindrical element 520. Additionally, rotatable sections 530(n) and 530(n+2) are preferably identical to rotatable section 530(1).

[0085]

[0103] Portion 524 is provided with an outer edge 526 that faces an outer edge 528 of hinge portion 522(1). Outer edge 526 and outer edge 528 define an open space therebetween so that once bridge 552(1) breaks, portion 524 and hinge portion 522(1) are free to rotate relative to one another about extension 548(1) up to a predetermined bend angle reached when outer edges 526 and 528 contact one another.

[0086]

[0104] The outer edges 526 and 528 result from cutting, e.g., a laser cutting or water cutting process, a predetermined pattern into the cylindrical element 520. All adjacent hinge portions 522(n), 522(n+1) have an open space therebetween, such as the space defined between portion 524 and hinge portion 522(1), which results from a cutting process, e.g., a laser cutting or water cutting process. These spaces are alternately rotated 90° in the tangential direction of the cylindrical element 520.

[0087]

[0105] Because successive rotatable sections 530(n) and 530(n+1) are rotated approximately 90° relative to one another when viewed tangentially to cylindrical element 520, hinge portion 522(n-1) and hinge portion 522(n) rotate relative to one another in a first direction that is perpendicular to a second direction of rotation of hinge portion 522(n) relative to hinge portion 522(n+1). As shown, the direction of rotation between successive hinge portions alternates between the first and second directions, making hinge 521 flexible in all directions.

[0088]

[0106] In one example, each notch 550(n) is still attached to the extension 548(n) by a bridge 552(n) when the slot is created between the notch 550(n) and the extension 548(n). Thus, after the cylindrical element structure 520 of FIG. 5b is created, in such an example, all the various parts are still attached to each other and the structure does not fall apart into separate pieces. Furthermore, after the cylindrical element 520 is created, all the circular islands 556(n) are also still attached to the surrounding circular extension 548(n) by a bridge 540(n). Thus, when ready, the cylindrical element structure 520 of FIG. 5b is still an integral unit when the cylindrical element 500 is ready to be inserted into the cylindrical element structure 520. Furthermore, before being inserted into each other, both cylindrical elements 500, 520 still have a straight structure due to all the bridges 510(n), 552(n), which facilitates the action of inserting the two cylindrical elements 500, 520 into each other.

[0089]

[0107] Bridges 552(1) and 540(1) are designed as "breakable elements" as described herein above, i.e., they break when subjected to a predetermined force that is less than the force required to deform the surrounding material beyond its maximum elasticity.

[0090]

[0108] 5c shows the resulting hinge structure when the cylindrical elements 500, 520 are inserted into each other. As shown, in the assembled state, the cylindrical elements 500, 520 are aligned with each other both longitudinally and tangentially such that each rotatable section 530(n) of the cylindrical element 520 is aligned with one rotatable section 507(n) of the cylindrical element 500. To complete the assembly, after the cylindrical element 500 is inserted into the cylindrical element 520, each mounting structure 544(n) is attached to one of the circular extensions 506(n) by, for example, gluing, soldering, welding, or laser welding. Optionally, one or more hinge portions 522(n) are also attached to the hinge portion 502(n), for example, by gluing, soldering, welding, or laser welding the lip 554(n) to the hinge portion 502(n). This latter action imparts greater stiffness to the overall hinge structure.

[0091]

[0109] Portion 529 can be attached to portion 509 in a similar manner, for example, by gluing, soldering, welding, or laser welding lip 534 to portion 509, or in any other suitable manner. Similarly, portions 504 and 524 can be attached to one another.

[0092]

[0110] After cylindrical elements 500 and 520 are attached to each other in this manner, a user can apply a rotational force in the direction indicated by double arrow 503 in FIG. 5a. By exceeding a certain threshold of rotational force, all breakable elements 510(n), 540(n), and 552(n) break. As a result, portions 504 / 524 can freely rotate about pin 556(1) relative to adjacent hinge portions 502(1) / 522(1), and hinge portions 502(n) / 522(n) can freely rotate about pin 556(n+1) relative to adjacent hinge portions 502(n+1) / 522(n+1). Similarly, portions 509 / 529 can freely rotate relative to hinge portions 502(N) / 522(N).

[0093]

[0111] Furthermore, each circular island 556(n) is rigidly attached to a circular extension 506(n) in the cylindrical element 500 and can freely rotate with the circular extension 506(n) in the extension 548(n) of the cylindrical element 520. With this construction, the circular island 556(n) acts as a pin or spindle that has two functions. First, it acts as a rotation pin about which the extension 548(n) rotates. Second, because the slot between the pin 556(n) and the extension 548(n) can be made very narrow, the pin 556(n) acts to keep the hinge portion 502(n) / 522(n) and the adjacent hinge portion 502(n+1) / 522(n+1) in a well-defined position relative to each other with very little play between them. The same is true for the position of portions 504 / 524 relative to hinge portions 502(1) / 522(1) and the position of hinge portions 502(N) / 522(N) relative to portions 509 / 529.

[0094]

[0112] 6 shows a schematic cross-sectional view of an extension 506(n) of a cylindrical element 500 and how such extension 506(n) is attached to a pin 556(n), which is rotatably arranged in a hole of an extension 548(n) in the cylindrical element 520 defined by a slot 542(n). The pin 556(n) is attached to the extension 506(n), for example, by (laser) welding a mounting structure 544(n) to the extension 506(n). As the structure is rotationally symmetric, the cylindrical element 500 has two such pins 556(n) on either side of its axis of symmetry 500c (and therefore at a tangentially rotated position of 180°), both housed in holes defined by slots 542(n) in the extension 548(1) of the cylindrical element 520. This provides a rigid structure in which adjacent portions of the hinge structure are connected to each other yet can freely rotate relative to each other. Note also that adjacent hinge portions 502(n) / 522(n) and 502(n+1) / 522(n+1) are no longer attached to each other by any portion of the material of either cylindrical element 500 or cylindrical element 520. Thus, there is no elastic deformation of the material that would generate a counter rotational force during rotation.

[0095]

[0113] Figure 7 shows that pin 556(n) can further be attached to extension 848(n) of cylindrical element 820 that surrounds cylindrical element 520, as shown in Figures 8a and 8b. This can be done by gluing, soldering, welding or laser welding extension 848(n) to pin 556(n) by attachment structure 844(n).

[0096]

[0114] FIG. 8a shows cylindrical element 820 in more detail.

[0097]

[0115] Figure 8a shows a cylindrical element 820 with a hinge 821 made as a slotted structure. The cylindrical element 820 comprises a portion 824 and a further portion 829 opposite the portion 824. The hinge 821 is located between them.

[0098]

[0116] Hinge 821 comprises a plurality of hinge portions 822(1), 822(2), ... 822(n), ... 822(N), where N is an integer greater than 1. In the illustrated example, each hinge portion 822(n) has an identical shape, but this need not be the case. Each hinge portion 822(n) as illustrated is a rigid ring-shaped portion of cylindrical element 820.

[0099]

[0117] Part 824 and hinge part 822(1) are arranged to be rotatable relative to each other by means of two rotatable sections 830(1) (only one is visible in FIG. 8b), which are rotated 180° relative to each other when viewed in the tangential direction of cylindrical element 821. One such rotatable section 830(1) is shown in detail in FIG. 8c, as indicated by the dotted circle Vd in FIG. 8b. The line connecting both rotatable sections 830(1) intersects the central axis of hinge 821. Part 824 and hinge part 822(1) are therefore rotatable about this line.

[0100]

[0118] As shown in FIG. 8c, the rotatable section 830(1) comprises an extension 848(1) provided with a circular outer edge. This circular extension 848(1) is received in a circular notch 850(1) of the hinge portion 822(1). The radius of the circular extension 848(1) and the radius of the circular notch 850(1) are the same. They have the same center of rotation. The circular extension 848(1) and the circular notch 850(1) are separated by a small slot made by a cutting operation, e.g., a laser or water cutting operation, or any other suitable cutting technique. During the creation of the slot, the slot is interrupted in a predetermined position, so that the extension 848(1) and the notch 850(1) are still attached to each other by one or more small bridges 852(1). These bridges 852(1) act as "breaking elements" as defined above, i.e., they break when a force above a certain threshold is applied. Here, they are designed to break upon rotating portion 824 and hinge portion 822(1) relative to one another about two extensions 848(1) with at least such a threshold force. The threshold force is selected so that bridge 852(1) breaks before either portion 824 or hinge portion 822(1) is deformed beyond its maximum elasticity by the applied rotational force. They only break later during the manufacturing process, as described below.

[0101]

[0119] Reference numeral 844(1) refers to an attachment structure within circular extension 848(1). Attachment structure 844(1) is positioned such that circular extension 848(1) can be attached to pin 556(1) of cylindrical element 520 after cylindrical element 520 is inserted into cylindrical element 848. Such attachment can be by any suitable attachment technique, including gluing, soldering, welding, and laser welding. To aid in laser welding, attachment structure 844(1) can be formed as a small, slotted structure in an S-shape, for example, made by a laser cutting or water cutting process.

[0102]

[0120] Hinge portion 822(1) may be provided with one or more lips 854(1) (one is shown in FIGS. 8b and 8c). Such lip 854(1) may be located adjacent lip 554(1) of cylindrical element 520 (see FIG. 5d). Lip 854(1) is used to attach hinge portion 822(1) of cylindrical tube 820 to hinge portion 522(1) of cylindrical element 520 after insertion of cylindrical element 520 into cylindrical element 820, for example by welding or laser welding. In so doing, hinge portions 502(1), 522(1), and 822(1) are securely attached to one another.

[0103]

[0121] Note that extension 506(1) of cylindrical element 500 is oriented in the same longitudinal direction as extension 848(1) of cylindrical element 820, but both of these extensions are oriented in the opposite longitudinal direction as extension 548(1) of cylindrical element 520. Extension 548(1) can thus rotate between extensions 506(1) and 848(1) about pin 556(1), which is attached at one end to extension 506(1) and at its opposite end to extension 848(1).

[0104]

[0122] Referring again to FIG. 8a, hinge portion 822(1) and hinge portion 822(2) are arranged to be able to rotate relative to each other about two rotatable sections 830(2) (only one is shown in FIG. 8a), which are located at 180° rotation relative to each other when viewed in the tangential direction of cylindrical element 820. The structure of rotatable section 830(2) is preferably identical to rotatable section 830(1). Thus, rotatable section 830(2) preferably has the same elements as rotatable section 830(1) shown in FIG. 8c, where all indices (1) are replaced by (2). Rotatable section 830(2) is located at a position rotated 90° relative to the position of rotatable section 830(1) when viewed in the tangential direction of cylindrical element 820.

[0105]

[0123] Defined in more general terms, the rotation mechanism between two adjacent hinge portions 822(n) and 822(n+1) is as follows: the hinge portions 822(n) and 822(n+1) are arranged so that they can rotate relative to each other about two rotatable sections 830(n+1), which are located rotated 180° relative to each other when viewed in the tangential direction of the cylindrical element 820. The structure of the rotatable section 830(n+1) is preferably identical to the rotatable section 830(1). Thus, the rotatable section 830(n+1) has the same elements as the rotatable section 830(1) shown in FIG. 8c, where all indices (1) are replaced by (n+1). Rotatable section 830(n+1) is located at a position rotated 90° with respect to the positions of rotatable sections 830(n) and 830(n+2) when viewed in the tangential direction of cylindrical element 820. Additionally, rotatable sections 830(n) and 830(n+2) are preferably identical to rotatable section 830(1).

[0106]

[0124] Part 824 is provided with an outer edge 826 that faces an outer edge 828 of hinge part 822(1). Outer edge 826 and outer edge 828 define an open space therebetween, such that once bridge 852(1) breaks, part 824 and hinge part 822(1) are free to rotate relative to one another about extension 848(1) up to a predetermined bend angle reached when outer edges 826 and 828 contact one another.

[0107]

[0125] Outer edges 826 and 828 result from cutting, e.g., a laser cutting or water cutting process, a predetermined pattern into cylindrical element 820. All adjacent hinge portions 822(n), 822(n+1) have an open space therebetween, such as the space defined between portion 824 and hinge portion 822(1), which results from a cutting process, e.g., a laser cutting or water cutting process. These spaces are alternately rotated 90° in the tangential direction of cylindrical element 820.

[0108]

[0126] Because successive rotatable sections 830(n) and 830(n+1) are rotated approximately 90° relative to one another when viewed tangentially to cylindrical element 820, hinge portion 822(n-1) and hinge portion 822(n) rotate relative to one another in a first direction that is perpendicular to a second direction of rotation of hinge portion 822(n) relative to hinge portion 822(n+2). As shown, the direction of rotation between successive hinge portions alternates between the first and second directions, making hinge 821 flexible in all directions.

[0109]

[0127] In one example, each notch 850(n) is still attached to the extension 848(n) by a bridge 852(n) when a slot is created between the notch 850(n) and the extension 848(n). Thus, after the cylindrical element structure 820 of FIG. 8b is created, in such an example, all the various parts are still attached to each other and the structure does not fall apart into separate pieces. Thus, when ready, the cylindrical element structure 820 of FIG. 8a is still an integral unit when the cylindrical element 520 is ready to be inserted into the cylindrical element structure 820. Furthermore, before being inserted into each other, both cylindrical elements 520, 820 still have a straight structure due to all the bridges 552(n), 852(n), facilitating the action of inserting the two cylindrical elements 520, 820 into each other.

[0110]

[0128] Bridges 852(1) and 840(1) are designed as "breakable elements" as defined herein above, i.e., they break when subjected to a predetermined force that is less than the force required to deform the surrounding material beyond its maximum elasticity.

[0111]

[0129] 8b shows the resulting hinge structure when the cylindrical elements 500, 520, and 820 are inserted into one another. As shown, in the assembled state, the cylindrical elements 500, 520, 820 are aligned with one another longitudinally and tangentially such that each rotatable section 530(n) of the cylindrical element 520 is aligned with both one rotatable section 507(n) of the cylindrical element 500 and one rotatable section 830(n) of the cylindrical element 820. To complete the assembly, after the cylindrical element 500 is inserted into the cylindrical element 520, each pin 556(n) is attached to one circular extension 506(n) by, for example, a mounting structure 544(n), for example by gluing, soldering, welding, or laser welding. Thereafter, after inserting cylindrical element 520 together with cylindrical element 500 into cylindrical element 820, each extension 848(n) is attached to pin 556(n) by, for example, mounting structure 844(n), for example, by gluing, soldering, welding, or laser welding.

[0112]

[0130] Optionally, one or more hinge portions 822(n) are also attached to hinge portion 522(n), for example, by gluing, soldering, welding, and / or laser welding lip 854(n) to lip 554(n). This latter action provides greater stiffness to the overall hinge structure.

[0113]

[0131] Portion 829 can be attached to portion 529 in a similar manner, for example, by gluing, soldering, welding, or laser welding lip 834 to portion 529, or in any other suitable manner. Similarly, portions 524 and 824 can be attached to one another.

[0114]

[0132] After cylindrical elements 500, 520, and 820 are attached to one another in this manner, a user can apply a rotational force in the direction indicated by double arrow 803 in FIG. 8a. By exceeding a certain threshold of rotational force, all of the "breaking elements" 510(n), 540(n), 552(n), and 852(n) will break. As a result, portions 504 / 524 / 824 can freely rotate about pin 556(1) relative to adjacent hinge portions 502(1) / 522(1) / 822(1), and hinge portions 502(n) / 522(n) / 822(n) can freely rotate about pin 556(n+1) relative to adjacent hinge portions 502(n+1) / 522(n+1) / 822(n+1). Similarly, portions 509 / 529 / 829 are free to rotate relative to hinge portions 502(N) / 522(N) / 822(N).

[0115]

[0133] Additionally, each circular island 856(n) is rigidly attached to a circular extension 548(n) in the cylindrical element 520 and can freely rotate therewithin the extension 848(n) of the cylindrical element 820. With this construction, the circular island 856(n) acts as a pin or spindle that has two functions. First, it acts as a rotation pin about which the extension 848(n) rotates. Second, because the slot between the pin 856(n) and the extension 848(n) can be made very narrow, the pin 856(n) acts to keep the hinge portion 822(n) / 522(n) and the adjacent hinge portion 822(n+1) / 522(n+1) in a well-defined position relative to each other with very little play between them. The same is true for the position of portion 824 / 524 relative to hinge portion 822(1) / 522(1) and the position of hinge portion 822(N) / 522(N) relative to portion 829 / 529.

[0116]

[0134] Figures 9a, 9b and 9c show an embodiment of the hinge structure of the present invention applied to a steerable device having a longitudinal element cut out of a cylindrical element and arranged as a steering strip for the steerable device. Such a steerable device may be based on any one of the devices shown with reference to Figures 1 to 4. In the following, the application of the hinge structure of the present invention is described with reference to a steerable device having a steering strip in one cylindrical element. However, the present invention can be applied to any steerable device having one or more cylindrical elements with a steering strip cut out of the cylindrical element.

[0117]

[0135] Figure 9a shows an inner cylindrical element, Figure 9b shows an intermediate cylindrical element with such a steering strip with the inner cylindrical element inserted therein, and Figure 9c shows an outer cylindrical element with a set of inner and intermediate cylindrical elements inserted therein.

[0118]

[0136] FIG. 9a shows an example of the tip of the inner cylindrical element 920, which may be at the distal or proximal end of the instrument. In this description, it is assumed to be at the distal end, but a similar structure may be at the proximal end. Alternatively, the steering strip may be steered by a ball-shaped member or a motor of a robotic steering mechanism. As mentioned above, the tip of the instrument is steerable. The inner cylindrical element may be completely flexible and may be made of any suitable material, including any type of plastic or metal that can be used in a medical environment. The structure of FIG. 9a is just one example of a possible embodiment, where flexibility is provided by a slotted hinge structure 921.

[0119]

[0137] Slotted hinge structure 921 is disposed proximally from ring-shaped end portion 924 of cylindrical element 920. Slotted hinge structure 921 includes a plurality of hinge portions 922(1), 922(2),..., 922(n),..., 922(N). End portion 924 is rotatably disposed relative to hinge portion 922(1), which in turn is rotatably disposed relative to cylindrical element portion 929, which is disposed proximally from hinge structure 921.

[0120]

[0138] End portion 924 can rotate relative to hinge portion 922(1) about two rotating sections 930(1) that are rotated 180° relative to each other when viewed tangentially to cylindrical element 920. That is, a line connecting the two rotating sections 930(1) intersects the axis of symmetry of cylindrical element 920. When end portion 924 rotates relative to hinge portion 922(1), the rotation is about this line.

[0121]

[0139] Between each two adjacent hinge portions 922(n) and 922(n+1), there are two rotating sections 930(n+1), so that they can rotate relative to each other about a line connecting these two rotating sections 930(n+1). In one embodiment, all rotating sections 930(n) are identical, although this is not strictly necessary.

[0122]

[0140] An example of such a rotating section 930(n) is provided with reference to rotating section 930(2). Rotating section 930(2) is located between hinge portions 922(1) and 922(2). Rotated 180 degrees relative to the location of rotating section 930(2) is a second rotating section 930(2). Rotating section 930(2) comprises a circular extension 948(2) of hinge portion 922(1). Extension 948(2) is received within a circular notch 950(2) of hinge portion 922(2). Extension 948(2) and notch 950(2) are separated by a slot cut into cylindrical element 920. During cutting to create the slots, for example by laser or water cutting processes, extensions 948(2) and notches 950(2) remain attached to one another by small bridges 952(2) that act as "breaking elements" as described above, i.e., they are designed to break upon rotation of hinge portions 922(1) and 922(2) relative to one another at a predetermined force below the force required to deform the surrounding material of hinge portions 922(1) and 922(2) beyond their maximum elasticity, but above a certain threshold force.

[0123]

[0141] The center point of extension 948(2) defines the rotation point about which hinge portions 922(1) and 922(2) can rotate when bridge 952(2) breaks.

[0124]

[0142] Rotating section 930(2) also includes two lip elements 960(2), 962(2) extending from hinge portion 922(2) toward hinge portion 922(1). Both lip elements 960(2) and 962(2) have a circular shape and are spaced a radial distance from the point of rotation that is greater than the radius of circular extension 948(2). Lip element 960(2) can move in a circular direction within a circular slot 964(2) disposed in hinge portion 922(1). Lip element 962(2) can move in a circular direction within a circular slot 966(2) disposed in hinge portion 922(1).

[0125]

[0143] Lip elements 960(2), 962(2) and circular slots 964(2), 966(2) may be formed by cutting a predetermined pattern into cylindrical element 920, such as by a laser cutting or water cutting process, as would be apparent to one of ordinary skill in the art. During the cutting process, lip elements 960(2) and 962(2) may remain attached to the surrounding material from hinge portion 922(1) by a small bridge that acts as the "break-off element" described above.

[0126]

[0144] Lip elements 960(2) and 962(2) receive a portion of hinge portion 922(1), including circular extension 948(2), thereby preventing hinge portions 922(1) and 922(2) from easily moving relative to one another in the longitudinal direction of cylindrical element 920.

[0127]

[0145] Hinge portion 922(1) has an edge 968 facing an edge 970 of hinge portion 922(2) that is shaped to define a predetermined open space between hinge portions 922(1) and 922(2). This open space and the length of slots 964(2), 966(2) determine the angle through which hinge portions 922(1) and 922(2) can rotate relative to one another.

[0128]

[0146] It should be noted that rotating hinge portions 922(1), 922(2) relative to one another in the direction indicated by double arrow 903 with a predetermined force above a predetermined threshold will cause breakage element 952(2) (and possible breakage elements attaching lip elements 960(2), 962(2) to the adjacent material of hinge portion 922(1)) to break, such that hinge portions 922(1) and 922(2) are no longer attached to one another and can rotate freely. However, this is preferably not done prior to inserting inner cylindrical element 920 into intermediate cylindrical element 1000 shown in FIG. 9b.

[0129]

[0147] Again, successive rotating sections 930(n) and 930(n+1) are rotated 90° tangentially to the cylindrical element 920, giving the hinge structure 921 complete flexibility in all directions.

[0130]

[0148] FIG. 9b shows an example of an intermediate cylindrical element 1000. The intermediate cylindrical element 1000 comprises a ring-shaped distal end portion 1002 attached to a number of steering strips 1004, here made by cutting the cylindrical element 1000 and, for example, laser cutting or water cutting to form longitudinal elements. When bendability in one direction (and the opposite direction) is desired, two such steering strips 1004 are sufficient. However, if bendability in all directions is desired, at least three steering strips 1004 should be applied. The steering strips 1004 are, in one example, located at equidistant positions in the tangential direction. In this example, eight such steering strips 1004 are applied.

[0131]

[0149] As shown in FIG. 9b, two adjacent steering strips 1004 are prevented from moving tangentially relative to each other by tangential spacers. Two different sets of tangential spacers are shown. The first set comprises spacers 1028 formed as longitudinal strips with spacer elements on either side that extend tangentially to such an extent that they contact the adjacent steering strips 1004. These spacer elements may have any desired form, i.e. flexible plate-like elements, M-shaped elements, S-shaped elements, pin-shaped elements, or any other suitable form known to those skilled in the art. The spacers 1028 may alternatively be formed as flexible plate-like elements, M-shaped elements, S-shaped elements, pin-shaped elements, or any other suitable form known to those skilled in the art, directly attached to either one of the two adjacent steering strips 1004 and extending to the other of the two adjacent steering strips 1004, as known from the prior art.

[0132]

[0150] The second set of tangential spacers comprises a plurality of spacer elements 1005 arranged consecutively in the longitudinal direction between two adjacent steering strips 1004. The first set of spacers 1028 and the second set of spacers 1005 alternate in the tangential direction of the cylindrical element 1000.

[0133]

[0151] Each spacer element 1005 comprises a plate 1006 separated from an adjacent steering strip 1004 by a slot resulting from a cut, e.g., a laser or water cutting process, in the cylindrical element 1000. During the cutting process, the plate 1006 remains attached to one or both adjacent steering strips 1004 by a "breaking element" 1012, preferably a breaking element as described herein above. The breaking element 1012 is designed such that when a relative longitudinal force is applied between the steering strip 1004 and the plate 1006 to which it is attached, the breaking element 1012 breaks if the force exceeds a certain threshold force. The threshold force should be selected such that the resulting forces on the steering strip 1004 and the plate 1006 remain below their maximum elasticity.

[0134]

[0152] In the illustrated embodiment, the plate 1006 is attached to a further plate 1014 separated from the adjacent steering strip 1004 by a slot cut into the cylindrical element 1000, e.g., by a laser or water cutting process. During the cutting process, the plate 1014 preferably remains attached to one or both adjacent steering strips 1004 by a "breaking element" 1016. The breaking element 1016 is designed such that when a relative longitudinal force is applied between the steering strip 1004 and the plate 1014 to which it is attached, the breaking element 1016 breaks if the force exceeds a certain threshold force. The threshold force should be selected such that the resulting forces on the steering strip 1004 and the plate 1014 remain below their maximum elasticity.

[0135]

[0153] In one example, plate 1006 is attached to plate 1014 by flexible attachment strips 1018, so that they are spaced a predetermined longitudinal distance from each other, such that attachment strips 1018 can extend into plate 1014 (and / or into plate 1006) by having slots on either side, as shown in FIG.

[0136]

[0154] Plate 1014 has an edge 1020 facing toward the distal end and plate 1006 has an edge 1022 facing toward the proximal end. Successive spacer elements 1005 are longitudinally spaced from one another at a predetermined distance determined by the particular required flexibility of the device.

[0137]

[0155] When cylindrical elements 920 and 1000 are manufactured, they are both one-piece cylindrical elements with all the various components still attached to each other by the break elements as described above. They are still straight and cylindrical element 920 can be easily inserted into cylindrical element 1000. Once inserted into each other, they are aligned both longitudinally and tangentially. Then, in one embodiment, ends 924 and 1002 are attached to each other, for example, by gluing, soldering, welding, laser welding, etc.

[0138]

[0156] When inserted into each other, the set of cylindrical elements 920, 1000 is inserted into a cylindrical element that may have the same shape as the cylindrical element 520 described with reference to Figures 5b and 5d. Figure 9c shows the (e.g. distal) end structure of the device where this has been done. The set of cylindrical elements 920, 1000 is aligned both longitudinally and tangentially with the cylindrical element 520. This alignment is such that each pin 556(n) located inside the hinge portion 522(n-1) is radially aligned and attached to a portion 1008 of the plate 1006. This may be done by the attachment structure 544(n), if present. The attachment may be by gluing, welding, laser welding, etc. Furthermore, the portion of the hinge portion 522(n) located longitudinally offset from the pin 556(n) is attached to the plate 1006 at a portion 1010 also longitudinally offset from the portion 1008. This portion of the hinge portion 522(n) may be the lip 554(n). In this manner, each pin 556(n) located inside the hinge portion 522(n-1) is firmly attached to the hinge portion 522(n) by one single plate 1006 that is itself located within the intermediate cylindrical element 1000. Furthermore, the plate 1006 also functions as a tangential spacer between adjacent steering strips within the intermediate cylindrical element 1000.

[0139]

[0157] Preferably, after longitudinal and tangential alignment has been achieved, end portion 524 is attached to end portion 1002 .

[0140]

[0158] After all three cylindrical elements 920, 1000, 520 have been inserted into one another, aligned longitudinally and tangentially as desired, and attached to one another as described above, the user can bend the device by applying a rotational force 903 (see FIG. 9a) in all directions with such a force that all breakable elements still holding the separate components attached to one another break but the surrounding materials are not subjected to forces beyond their maximum elasticity. All rotating sections within the inner cylindrical element 920 and the outer cylindrical element 520 are then free to rotate. Since several components are elastically bending, the only reaction force resisting any bending is generated in the middle cylindrical element 1000.

[0141]

[0159] Of course, the device of Figures 9a, 9b and 9c may be fitted with further outer cylindrical elements, such as cylindrical element 820 (Figure 8a), to impart higher stiffness to the overall structure.

[0142]

[0160] Although the embodiments of Figures 9a, 9b, and 9c show the plate 1006 inside the rotating section 530(n), the cylindrical elements 1000 and 520 may be designed such that the cylindrical element 520 is inserted into the cylindrical element 1000 and the plate 1006 is located outside the rotating section 530(n).

[0143]

[0161] 10a and 10b show an embodiment of the hinge structure of the present invention applied to a steerable device having a steering cable or wire acting as a steering element of the steerable device. Such a steerable device may be based on any steerable device provided with a steering cable known from the prior art. For example, such a steerable device may be based on any one of the embodiments described in non-prepublished PCT / NL2019 / 0506850.

[0144]

[0162] Figure 10a shows an intermediate cylindrical element 1000a provided with steering cables 1004a and assembled in coaxial alignment with the inner cylindrical element 920 shown in Figure 9a. Figure 10b shows the inner cylindrical element 920 and the intermediate cylindrical element 1000a assembled with the outer cylindrical element 520a and aligned longitudinally and tangentially. Note that the outer cylindrical element 520a may be identical to the outer cylindrical element 520 shown in Figure 9c.

[0145]

[0163] FIG. 10a shows an example of an intermediate cylindrical element 1000a that is substantially similar to the intermediate cylindrical element 1000 of FIG. 9b, but with a steering cable 1004a instead of the steering strip 1004. In FIG. 10a, elements corresponding to those of FIG. 9b are indicated by corresponding reference numerals given the suffix "a". It should be understood that these features are advantageously similar to the corresponding features described with reference to FIG. 9b and may be modified, where applicable, to facilitate the use of a steering cable 1004a instead of the steering strip 1004, as will be understood by those skilled in the art. Accordingly, the description of the various features will not be repeated herein.

[0146]

[0164] The intermediate cylindrical element 1000a comprises a ring-shaped distal end portion 1002a attached to a number of steering cables 1004a. When bendability in one direction (and the opposite direction) is desired, two such steering cables 1004a are sufficient. However, if bendability in all directions is desired, at least three steering cables 1004a should be applied. The steering cables 1004a are, in one example, located at equidistant tangential positions.

[0147]

[0165] As shown in Figure 10a, two adjacent steering cables 1004a are prevented from moving tangentially relative to one another by tangential spacers. Two different sets of tangential spacers are shown. The first set includes a spacer 1028a formed as a longitudinal strip with spacer elements on either side that extend tangentially to such an extent that they contact the adjacent steering cable 1004a.

[0148]

[0166] The second set of tangential spacers comprises a plurality of spacer elements 1005a arranged longitudinally consecutively between two adjacent steering cables 1004a. The first set of spacers 1028a and the second set of spacers 1005a alternate in the tangential direction of the cylindrical element 1000a.

[0149]

[0167] Each spacer element 1005a includes a plate 1006a separated from the adjacent steering cable 1004a by a slot.

[0150]

[0168] In the illustrated embodiment, the plate 1006a is attached to a further plate 1014a that is separated from the adjacent steering cable 1004a by a slot.

[0151]

[0169] In one example, plate 1006a is attached to plate 1014a by flexible mounting strips 1018a such that they are spaced a predetermined longitudinal distance from each other.

[0152]

[0170] When cylindrical elements 920 and 1000a are manufactured, they are both integral cylindrical elements with all the various components still attached to each other by the break elements as described above. They are still straight and cylindrical element 920 can be easily inserted into cylindrical element 1000a. Once inserted into each other, they are aligned both longitudinally and tangentially. Then, in one embodiment, ends 924 and 1002a are attached to each other, for example, by gluing, soldering, welding, laser welding, etc.

[0153]

[0171] Once inserted into each other, the set of cylindrical elements 920, 1000a is inserted into a cylindrical element that may have the same shape as the cylindrical element 520 described with reference to Figures 5b and 5d. Figure 10b shows the (e.g. distal) end structure of the device where this has been done. The set of cylindrical elements 920, 1000a is aligned both longitudinally and tangentially with the cylindrical element 520. This alignment is such that each pin 556(n) located inside the hinge portion 522(n-1) is radially aligned and attached to a portion 1008a of the plate 1006a. This may be done by the attachment structure 544(n), if present. The attachment may be done by gluing, welding, laser welding, etc. Furthermore, a portion of the hinge portion 522(n) that is longitudinally offset from the pin 556(n) is attached to the plate 1006a at the portion 1010a that is longitudinally offset from the portion 1008a. This portion of the hinge portion 522(n) may be the lip 554(n). In this manner, each pin 556(n) located inside the hinge portion 522(n-1) is rigidly attached to the hinge portion 522(n) by one single plate 1006 that is itself located within the intermediate cylindrical element 1000a. Furthermore, the plate 1006a also functions as a tangential spacer between adjacent steering cables within the intermediate cylindrical element 1000a.

[0154]

[0172] Preferably, after longitudinal and tangential alignment has been achieved, end portion 524 is attached to end portion 1002a.

[0155]

[0173] After all three cylindrical elements 920, 1000a, 520 have been inserted into one another, aligned longitudinally and tangentially as desired, and attached to one another as described above, the user can bend the device by applying a rotational force 903 (see FIG. 9a) in all directions with such a force that all breakable elements still holding the separate components attached to one another break but the surrounding materials are not subjected to forces beyond their maximum elasticity. All rotating sections within the inner cylindrical element 920 and the outer cylindrical element 520 are then free to rotate. A reaction force that resists any bending is then generated only on the middle cylindrical element 1000a, as several components are elastically bending.

[0156]

[0174] Of course, the device of Figures 10a, 10b may be fitted with further outer cylindrical elements, such as cylindrical element 820 (Figure 8a), to impart higher stiffness to the overall structure.

[0157]

[0175] Although the embodiment of Figures 10a and 10b shows plate 1006a inside rotating section 530(n), cylindrical elements 1000a and 520 may be designed such that cylindrical element 520 is inserted into cylindrical element 1000a and plate 1006a is located outside rotating section 530(n).

[0158]

[0176] The invention is not limited to the embodiments described so far. In the above-mentioned embodiment, adjacent hinge parts 522(n), 522(n+1) of a cylindrical hinge 521 can rotate relative to each other because one of them is provided with two holes located tangentially opposite each other. Each hole receives a pin 556(n) attached to an element 506(n), 1006 on the inside of the cylindrical hinge 521 and / or to an element 848(n) on the outside of the cylindrical element 521, which element 506(n), 1006 or 848(n) is also attached to a part of the other hinge part. The pins therefore remain inside their corresponding holes and the adjacent hinge parts remain at a well-defined distance from each other. They can rotate freely relative to each other about the pin 556(n).

[0159]

[0177] However, the pin itself does not have to be the center of rotation, as will be explained with reference to FIG.

[0160]

[0178] Fig. 11 shows an alternative form of the outer cylindrical element 520. Fig. 11 shows the cylindrical element 1000 inserted into the cylindrical element 1100. Inside the cylindrical element 1000 there can be any other suitable flexible cylindrical element as described above with reference to the cylindrical element 920. Again there can be more cylindrical elements with steering strips to control the bending of the deflectable section of the device. Alternatively, instead of the cylindrical element 1000, the cylindrical element 1000a can be inserted into the cylindrical element 1100 in a manner similar to that described herein below with reference to the cylindrical element 1000.

[0161]

[0179] Cylindrical element 1100 has an end portion 1124 that may be located at the distal end of the device. However, it may alternatively be at the proximal end. Adjacent to end portion 1124, cylindrical element 1100 comprises a plurality of hinge portions 1122(1), 1122(2), ..., 1122(n), ..., 1122(N) of a (cylindrical) hinge 1121. End portion 1124 is rotatable relative to hinge portion 1122(1), and similarly, end portion 1129 is rotatable relative to hinge portion 1122(N).

[0162]

[0180] Each hinge portion 1122(n-1) is rotatable relative to the adjacent hinge portion 1122(n) by two rotatable sections 1130(n). End portion 1124 is rotatable relative to the adjacent hinge portion 1122(1) by two rotatable sections 1130(1). Hinge portion 1122(N) is rotatable relative to end portion 1129 by two rotatable sections 1130(N+1). Each of the two rotating sections 1130(n) is located 180° rotated relative to each other in the tangential direction.

[0163]

[0181] Rotating section 1130(1) is shown in more detail, however, all other rotating sections 1130(n) are preferably similarly formed.

[0164]

[0182] End portion 1124 has an outer edge 1126 that faces toward an outer edge 1128 of hinge portion 1122(1). Outer edges 1126 and 1128 are designed to define an open space between end portion 1124 and hinge portion 1122(1). Edges 1126 and 1128 only contact each other at two predefined locations 1160(1). During manufacturing, these open spaces can be formed by cutting a predefined pattern into cylindrical element 1100, for example by a laser cutting process or a water cutting process. As long as cylindrical element 1000 has not yet been inserted into cylindrical element 1100, a breaking element can be applied at location 1160(1) to keep end portion 1124 and hinge portion 1122(1) still attached to each other. Location 1160(1) becomes the center of rotation.

[0165]

[0183] Hinge portion 1122(1) is provided with a pin 1156(1) that can move within a slot 1158(1) in hinge portion 1122(1). Slot 1158(1) is made by cutting, e.g., a laser cutting or water cutting process, into hinge portion 1122(1), simultaneously forming pin 1156(1). Pin 1156(1) is thus a disk that results from cutting into hinge portion 1122(1). Slot 1158(1) has a circular shape positioned on the arc of a circle centered at the same location as center of rotation 1160(1).

[0166]

[0184] Once the cylindrical element 1100 is prepared, the cylindrical element 1000 is inserted into the cylindrical element 1100 and properly aligned both longitudinally and tangentially. Note that in this embodiment, the cylindrical element 1000 includes spacer elements 1005 under all rotating sections 1130(n), which differs from FIG. 9c, which shows a slightly different spacer structure under the center of rotation 1130(1). In the embodiment of FIG. 11, the plate 1014 of the spacer elements 1005 under the rotating sections 1130(1) can be part of the end portion 1002. The center of rotation 1160(1) is aligned such that it is radially aligned with the flexible portion of the mounting strip 1018 between the plate 1014 and the plate 1006. The pin 1156(1) is attached to the plate 1006, for example, by gluing, welding, laser welding, etc. Additionally, a portion of end portion 1124 adjacent center of rotation 1160(1) is attached to plate 1014, for example, by gluing, welding, laser welding, or the like. This portion of end portion 1124 may be a lip 1154(1) cut into end portion 1124. In this manner, pin 1156(1) is attached to end portion 1124 but is held in place in slot 1158(1). Attachment strip 1018 prevents longitudinal displacement between end portion 1124 and hinge portion 1122(1). Because center of rotation 1160(1) lies above a flexible portion of attachment strip 1018 when viewed radially, end portion 1124 and hinge portion 1122(1) can rotate relative to one another about center of rotation 1160(1).

[0167]

[0185] End portion 1124 is preferably attached to end portion 1002, such as by welding, adhesive, or laser welding.

[0168]

[0186] The two rotating sections 1130(n) between adjacent hinge portions 1122(n-1) and 1122(n) preferably have the same design as the rotating section 1130(1). The center of rotation 1160(n) is aligned so as to be radially aligned with the flexible portion of the mounting strip 1018 between the plates 1014 and 1006. The pin 1156(n) is attached to the plate 1006, for example, by gluing, welding, laser welding, etc. Additionally, a portion of the hinge portion 1122(n-1) adjacent to the center of rotation 1160(n) is attached to the plate 1014, for example, by gluing, welding, laser welding, etc. This portion of the hinge portion 1122(n-1) may be a lip cut into the hinge portion 1122(n-1). In this manner, the pin 1156(n) is attached to the hinge portion 1122(n-1) but is held in place in the slot 1158(n). The attachment strip 1018 prevents longitudinal displacement between the hinge portion 1122(n-1) and the hinge portion 1122(n). The center of rotation 1160(n) is located above the flexible portion of the attachment strip 1018 when viewed radially, so that the hinge portion 1122(n-1) and the hinge portion 1122(n) can rotate relative to each other about the center of rotation 1160(n).

[0169]

[0187] The pins 556(n) have been described in the above embodiments herein as having a substantially flat disk shape that can be attached to the attachment members, i.e., extensions 506(n) and 848(n), by gluing, soldering, welding, or laser welding. However, it should be understood that in alternative embodiments, the pins 556(n) may be formed by elongated structures that include or are provided with protrusions and / or have radial extensions, such that the pins 556(n) can be attached to the attachment members, i.e., extensions 506(n), by mechanical connections such as snap-fits or form-fits, or the like, such that the pins are rotationally fastened to the attachment members. For example, the attachment members may be provided with attachment member openings into which the protrusions or elongated structures of the pins can be inserted and secured, for example by the protrusions or elongated structures having a diameter equal to or slightly larger than the attachment member openings. The pins may be fastened to the extensions 848(n) or plate 1006 in a similar manner.

[0170]

[0188] Again, the successive rotation centers 1130(n-1) and 1130(n) are preferably located at 90° rotational positions relative to each other in the tangential direction, such that the entire structure can be bent in any desired direction.

[0171]

[0189] It should be noted that when the user first applies a rotational force, the user breaks the aforementioned breakable elements between edges 1126, 1128 at the center of rotation 1160(1) and between pin 1156(1) and the surrounding material of hinge portion 1122(1). It should also be noted that pin 1156(1) is shown in FIG. 11 as having the shape of an arc of a circle having the same length as slot 1158(1) but a shorter length. However, pin 1156(1) may have any other suitable shape, such as a circular shape. The same applies to all other breakable elements and pins 1156(n), respectively. All pins 1156(n) may be provided with special attachment structures, such as slotted structures 1144(n), supporting attachment, such as by laser welding.

[0172]

[0190] The mutual gap between adjacent cylindrical elements is so small that they can easily move relative to each other in the longitudinal direction unless attached to each other, but the mutual radial play is kept to a minimum. The mutual gap may be in the range of 0.02-0.1 mm. The thickness of the cylindrical elements may be in the range of 0.1-2.0 mm, preferably 0.1-1.0 mm, more preferably 0.1-0.5 mm, most preferably 0.2-0.4 mm. The diameter of the cylindrical elements may be in the range of 0.5-20 mm, preferably 0.5-10 mm, more preferably 0.5-6 mm.

[0173]

[0191] Although the embodiments illustrated in Figures 5-11 are described with reference to the distal end 13 of the steerable instrument, it should be understood that the hinges described herein above may also be applied to other sections of the steerable instrument.

[0174]

[0192] All cylindrical elements described herein above are preferably manufactured from a single cylindrical tube of any suitable material such as stainless steel, cobalt chrome, shape memory alloys such as Nitinol, plastics, polymers, composites, or other cuttable materials. Alternatively, the cylindrical elements can be made by a 3D printing process. The thickness of the tube depends on the application. For medical applications, the thickness may range from 0.1 to 2.0 mm, preferably 0.1 to 1.0 mm, more preferably 0.1 to 0.5 mm, and most preferably 0.2 to 0.4 mm. The diameter of the inner cylindrical element depends on the application. For medical applications, the diameter may range from 0.5 to 20 mm, preferably 0.5 to 10 mm, and more preferably 0.5 to 6 mm.

[0175]

[0193] The slots and openings in all cylindrical elements can be made by laser or water cutting processes. The smaller slots, made only to separate adjacent elements, may preferably have a width in the range of 5-50 μm, more preferably 15-30 μm.

[0176]

[0194] It will be apparent to those skilled in the art that the scope of the present invention is not limited to the examples described above, and that multiple variations and modifications thereof are possible without departing from the scope of the present invention as defined in the appended claims. Although the present invention has been illustrated and described in detail in the drawings and description, such illustration and description should be considered as exemplary or illustrative only and not restrictive. The present invention is not limited to the disclosed embodiments, but comprises any combination of the disclosed embodiments that can provide advantages.

[0177]

[0195] The above embodiment is shown with bendable zones 14 and 15 at the proximal end of the device arranged to control the bending of the bendable zones 16, 17 at the distal end by two sets of longitudinal elements. The bendable zones 14, 15 can be replaced by other actuation means, such as suitable motors arranged to control the movement of the longitudinal elements. In a further alternative, such actuation means may be constructed as a ball to which the longitudinal elements are attached. Rotating the ball causes the longitudinal elements to move longitudinally, thus controlling the bending of the flexible zones 16, 17. This also applies to devices having only one steerable and bendable zone at their distal end, as described with reference to Figures 2g, 2h, 2i.

[0178]

[0196] Variations of the disclosed embodiments can be understood and achieved by those skilled in the art in implementing the claimed invention, by studying the figures, the description, and the appended claims. In the description and claims, the word "comprises" does not exclude other elements, and the indefinite article "a" or "an" does not exclude a plurality. Indeed, it should be interpreted as meaning "at least one". The mere fact that certain features are recited in mutually different dependent claims does not indicate that a combination of these features cannot be advantageously used. Any reference signs in the claims should not be interpreted as limiting the scope of the invention. Features of the above-mentioned embodiments and aspects can be combined, unless the combination of them results in an obvious technical contradiction.

Claims

1. A cylindrical element (520; 1100) having a central axis (520c; 1100c) and equipped with a hinge structure, A first portion (524; 1124; 522(n-1); 1122(n-1)), a second portion (522(1); 1122(1); 522(n); 1122(n)), said second portion being located at the same distance from said central axis as said first portion and rotatable relative to said first portion (524; 1124; 522(n-1); 1122(n-1)) about two rotation sections (530(1); 1130(1); 530(n); 1130(n)) arranged at 180° rotational angles relative to each other in the tangential direction of said cylindrical element, a mounting element (502(1); 1006; 502(n)); Pin (556(1); 1156(1); 556(n); 1156(n)), Equipped with The rotating sections (530(1); 1130(1); 530(n); 1130(n)) are an opening is provided in either the first portion (524; 1124; 522(n-1); 1122(n-1)) or the second portion (522(1); 1122(1); 522(n); 1122(n)) to receive the pin (556(1); 1156(1); 556(n); 1156(n)); the pin (556(1)); 1156(1); 556(n); 1156(n)) is attached to a portion (506(1); 506(n)) of the mounting element (502(1); 1006; 502(n)); and the other of the first portion (524; 1124; 522(n-1); 1122(n-1)) and the second portion (522(1); 1122(1); 522(n); 1122(n)) being attached to another portion of the mounting element (502(1); 1006; 502(n)); This is achieved by A cylindrical element whereby the first portion (524; 1124; 522(n-1); 1122(n-1)) and the second portion (522(1); 1122(1); 522(n); 1122(n)) cannot move relative to one another in the longitudinal, tangential and radial directions, but are configured to rotate relative to one another about a center of rotation.

2. The cylindrical element according to claim 1 , wherein the first portion and the second portion are arranged so as not to overlap each other in a radial direction extending substantially perpendicular to the central axis.

3. the one of the first or second apertured portion comprises a first rotating section portion (548(1)) provided with the aperture; 3. The cylindrical element of claim 1 or 2, wherein the other of the first part or the second part comprises a second rotating section part (550(1)) at least partially surrounding the first rotating section part, the second rotating section part being at least partially attached to the attachment element.

4. The cylindrical element of claim 3 , wherein the first rotating section portion and the second rotating section portion are spaced the same distance from the central axis.

5. 5. A cylindrical element as claimed in claim 3 or 4, wherein the first rotating section portion and the second rotating section portion comprise sections having complementary or rotatably mating shapes.

6. 6. A cylindrical element according to any one of claims 3 to 5, wherein the first rotating section portion is formed as an extension (548(1)) provided with a slot (542(1)) defining the outer edge of the opening and such that an island (556(1)) forming the pin is formed within the opening, and the second rotating section portion is formed by a notch (550(1)).

7. A cylindrical element according to any one of claims 1 to 6, wherein the first and second parts are made from a single cylindrical element, for example by a laser cutting or water cutting process.

8. A cylindrical element according to any one of claims 1 to 7, wherein the attachment element is located at a different distance from the central axis than the first and second portions.

9. The cylindrical element according to any one of claims 1 to 8, wherein the attachment element is a hinge portion (502(1); 502(n)) of a further hinge structure in a further cylindrical element (500) located inside the cylindrical element.

10. A cylindrical element according to any one of claims 1 to 8, wherein the mounting element is a tangential spacer (1006) between adjacent steering strips (1004) in a further cylindrical element located inside the cylindrical element.

11. A cylindrical element according to any one of claims 1 to 7, wherein the mounting element is a tangential spacer (1006) between adjacent steering cables (1004a) in a further cylindrical element located inside the cylindrical element.

12. 12. The cylindrical element of any one of claims 1 to 11, wherein the opening is a circular opening having a center that forms the center of rotation, and the pin (556(1); 556(n)) is disposed within the opening such that it is rotatable about the center of rotation.

13. 4. A cylindrical element according to any one of claims 1 to 3, wherein the opening is a slot (1158(1); 1158(n)) arranged along an arc of a circle having a centre forming the centre of rotation, and the pin (1156(1); 1156(n)) is arranged within the slot such that it is movable within the slot along the arc of the circle.

14. A cylindrical element according to any one of claims 1 to 13, wherein the pin is a disk cut out of the material located in the opening prior to cutting the opening.

15. A steerable device comprising a cylindrical element according to any one of claims 1 to 14.

16. The steerable device according to claim 15, dependent on any one of claims 10 or 11, wherein the steerable device has a distal end portion steerable by the steering strip (1004) or the steering cable (1004a), the steering strip (1004) being a longitudinal element cut out of the further cylindrical element (1000).

17. 17. The steerable device of claim 16, wherein the tangential spacer (1006) is a cut-out portion of the further cylindrical element (1000).

18. 1. A method for manufacturing a cylindrical element having a central axis and a hinge structure, the cylindrical element comprising: A first portion (524; 1124; 522(n-1); 1122(n-1)), a second portion (522(1); 1122(1); 522(n); 1122(n)), said second portion being located at the same distance from said central axis as said first portion and rotatable relative to said first portion (524; 1124; 522(n-1); 1122(n-1)) about two rotation sections (530(1); 1130(1); 530(n); 1130(n)) arranged at 180° rotational angles relative to each other in the tangential direction of said cylindrical element, a mounting element (502(1); 1006; 502(n)); Pin (556(1); 1156(1); 556(n); 1156(n)), Equipped with The rotating sections (530(1); 1130(1); 530(n); 1130(n)) are an opening is provided in either the first portion (524; 1124; 522(n-1); 1122(n-1)) or the second portion (522(1); 1122(1); 522(n); 1122(n)) to receive the pin (556(1); 1156(1); 556(n); 1156(n)); the pin (556(1)); 1156(1); 556(n); 1156(n)) is attached to a portion (506(1); 506(n)) of the mounting element (502(1); 1006; 502(n)); and the other of the first portion (524; 1124; 522(n-1); 1122(n-1)) and the second portion (522(1); 1122(1); 522(n); 1122(n)) being attached to another portion of the mounting element (502(1); 1006; 502(n)); This is achieved by whereby the first portion (524; 1124; 522(n-1); 1122(n-1)) and the second portion (522(1); 1122(1); 522(n); 1122(n)) cannot move relative to one another in the longitudinal, tangential and radial directions, but are configured to rotate relative to one another about a center of rotation; 1122(n-1))))))))))))))))))))))))))))))))))))))))))))))))))

19. inserting a further cylindrical element (500; 1000; 1000a) inside said single cylindrical element (520; 1100), said further cylindrical element (500; 1000; 1000a) comprising said mounting element (502(1); 1006; 502(n)), then attaching the pin (556(1); 1156(1); 556(n); 1156(n)) to the portion of the mounting element (502(1); 1006; 502(n)); attaching the other of the first portion (524; 1124; 522(n-1); 1122(n-1)) and the second portion (522(1); 1122(1); 522(n); 1122(n)) to another portion of the attachment element (502(1); 1006; 502(n)); 20. The method of claim 18, comprising:

20. during the insertion of said further cylindrical element (500; 1000) inside said single cylindrical element (520; 1100), breaking one or more breaking elements still attaching said pin (556(1); 1156(1); 556(n)) to the surrounding material of said single cylindrical element (520; 1100), said breaking being performed after attaching said pin (556(1); 1156(1); 556(n); 1156(n)) to a portion of said attachment element (502(1); 1006; 502(n)); attaching the other of the first portion (524; 1124; 522(n-1); 1122(n-1)) and the second portion (522(1); 1122(1); 522(n); 1122(n)) to another portion of the attachment element (502(1); 1006; 502(n)); 20. The method of claim 18 or 19, comprising:

21. A method according to any one of claims 18 to 20, comprising the act of making a steerable device according to any one of claims 15 to 17.

Images