Steerable instrument with steering unit

Abstract

A steerable instrument has a deflectable tip portion (13; 74; 75) at a distal side. A first steering wire (16(1); 429) is attached to the deflectable tip portion (13; 74, 75). The first steering wire (16(1); 429) is part of a tube (3; 102, 103; 121) and is separated from other parts of the tube (3; 102, 103; 121) by a first material removal pattern such that the first steering wire (16(1); 429) extends from a proximal end to a distal end of the steerable instrument. The steerable instrument has a steering unit with a control tube portion (301a(i); 302a(1,3); 431) coaxially arranged with the tube (3). The control tube portion (301a(i); 302a(1,3); 431) controls rotation of the first control tube portion (301a(i); 302a(1,3)) which causes longitudinal movement of the steering wire (16(1); 429) in order to deflect the deflectable tip portion (13; 74; 75)) in a first plane.

Description

STEERABLE INSTRUMENT WITH STEERING UNITFIELD OF THE INVENTION

[0001] The invention relates to a steerable instrument with steering unit.BACKGROUND OF THE INVENTION

[0002] Transformation of surgical interventions that require large incisions for exposing a target area into minimal invasive surgical interventions, i.e. requiring only natural orifices or small incisions for establishing access to the target area, is a well-known and ongoing process. Steerable surgical minimal invasive instruments in the field of gastroscopy, colonoscopy, endoscopy, laparoscopy, etc. are well-known in the art. These invasive instruments can comprise a steerable tube shaped device that enhances its navigation and steering capabilities. Such a steerable tube shaped device may comprise a proximal end part, a distal end part including at least one deflectable zone and a rigid or flexible intermediate part or shaft, wherein the steerable tube shaped device, at its proximal end, further comprises a steering arrangement that is adapted to deflect the distal deflectable zone relative to a central axis of the tube shaped device. The steering arrangement may be implemented by a hand held and hand operated steering device that translates arm, wrist and / or finger movements into the desired movement of the instrument’s distal part. Alternatively, the steering arrangement may be implemented by a robotic device that translates, for example, electric motor rotation in the desired movement of the instrument’s distal part.

[0003] Most of the known instruments are complex to manufacture resulting in expensive instruments. Often, the distal end of the instruments comprises a flexible zone that is composed of separate links with hinging pins, coils or flexible plastic extrusions. Steering cables are guided through holes through these links and / or through guiding tubes, eyes or hooks. Furthermore, the steering arrangement usually comprises conventional steering cables with, for instance, sub 1 mm diameters as control members, wherein the steering cables are arranged between related deflectable zones at the distal end part and the steering arrangements at the proximal end part of the tube shaped device.

[0004] Steering cables are often numerous, small and floppy and a connection between the wires and the robot actuators cannot be made by an end user on site. Another and more robust means of connecting an instrument to a robot, that can easily be performed by an operator on site, is required. Therefor steerable instruments used in robotic applications have in common that between the instrument shaft and the robot an appropriate connection box is provided. The box usually contains mechanical or electromechanical means that translate for example robot actuator motor rotation to the correct longitudinal displacement of the instrument’s steering cables. Furthermore, the box usually comprises an easy to attach connection interface to the robot. These connection boxes can be quite complex and expensive to manufacture and in most cases, this box is permanently attached to the instrument by the manufacturer.

[0005] In medical applications, contamination of an instrument after it has been used to perform a surgical procedure on a patient can result in undesired postoperative complications when used on a next patient. The contamination may be due to blood, other body fluids, tissue, etc. As a consequence of the contamination, the instrument may contain germs, viruses or other biological or chemical substances that could threat the health of the next patient on which the instrument is used.

[0006] One way of avoiding this contamination requires performing a thorough cleaning and sterilization of the instrument before each use. In many cases, the cleaning process is not capable of removing all contamination. Therefore, a risk of adverse effects on a patient that is treated with such an instrument still exists. Furthermore, the cleaning process is expensive and requires appropriate infrastructure and trained people. In order to prevent the risk of contamination, there is a preference for using disposable instruments that are used a single time and are thrown away after treating one patient. But, the high costs of state of the art instruments and the attached interface box enforces the multiple re-use of these instruments to keep the instrument cost per procedure at an acceptable level. A further huge disadvantage is that not only the instrument but also the attached interface box is thrown away after a limited number of uses. Commercially and looking from the perspective of waste management and costs thereof, this is not an optimal solution. Furthermore, because of theusually relatively large dimensions of the interface box, the packaging of such an instrument becomes quite bulky, contains a large volume of materials and occupies a significant amount of space during transport and storage, which even increases the cost and waste problem.

[0007] To enable single use commercial viability of these robotic instruments and to minimize waste and transport and storage space for these instruments, one can make a steerable instrument by making hinge constructions, steering cables and other required functional parts by laser cutting these parts integrally and pre-assembled out of tube elements. Further details regarding the design and fabrication of the abovementioned steerable instrument have been described for example in W02009 / 112060, WO2009 / 127236, WO2012128618, WO201217335a8, W02014011049, WO2015084174, W02016089202, W02017010883, WO2017014624, W02017082720, WO2017213491, W02018067004, W02019009710, W02020080938, W02020214027, W02020218920, WO2020218921, WO2022260518, and WO2023287286.

[0008] In combination with this method of building the instrument body, one could avoid an interface box by creating a coupling between the instrument steering wires directly on to the fully re-useable robot as is proposed in NL2030160B1.

[0009] NL2030160B1 describes an instrument in which a connection box is obsolete and in which the connection box functionality is fully transferred to the re-useable robot. This is enabled by the implementation of a method for directly coupling the instrument steering elements to the robot actuation output. Attaching the instrument to the robot can easily be performed by the end user and on site, in the operating theatre.

[0010] Besides instruments that are used on combination with robotic controllers, steerable instruments for minimal invasive surgery can also be used as a hand held and controlled device. Instead of the control box for attachment to a robot, these instruments usually comprise a handle that translates arm, wrist and / or finger movements into the desired movement of the instrument’s steering cables. Also here, comparable disadvantages arise. The handle can be complex and expensive and usually is even more bulky than a robotic connection box. Also the cost per instrument usually is so high that single use isnot attractive. An example of such an instrument is shown in US2015 / 0107396, in which an instrument is shown that comprises a permanently attached handle containing actuation means for bending the instrument distal part. Limitations and disadvantages of US2015 / 0107396 are as mentioned above. Furthermore, the proposed device is only capable of deflecting its distal portion in one plane.

[0011] Therefor also the category of hand held instruments can benefit from the strategy of making a single use instrument body as is described in W02009 / 1 12060, WO2009 / 127236, WO2012128618, WO201217335a8, W0201401 1049, WO2015084174, W02016089202, W02017010883, WO2017014624, W02017082720, WO2017213491, W02018067004, WO20 19009710, W02020080938, W02020214027, W02020218920, W020202 18921, WO2022260518, and WO2023287286, and combine this with a re-useable handle. Also here, an end user operable coupling between the instrument body and the handle is then required. Steerable instruments with detachable handles do exist, but the main drawback of these devices is that steering of the instrument tip is accomplished by a wrist like or ball joint section in the proximal end of the instrument body to which the steering cables are attached. The instrument is steered by moving the complete handle by wrist and arm movements. Furthermore, the proximal part of the instruments, just distal of the steering wrist, need to be held in place by a second hand or by a device like an introducer or trocar to be able to precisely steer the instrument. Generally, the handles do not have means for actuation of individual steering cable by finger movement only, whilst the handle can be held stationary.

[0012] Therefor also hand held instruments could benefit from a better solution for detachable handles in which coupling and actuation means are provided that enable steering of the instrument by finger movement only. A coupling as proposed in NL2030160B1 could be applied, but the handle then still needs mechanical or electro-mechanical mechanisms that translate finger movements into longitudinal displacement of the coupling fingers.

[0013] The current widely adapted philosophy of making the disposable part of a steerable device as simple as possible and transfer all ‘complexity’ to the reusable part of that device, which can either be a handle or a robot, was the basis for prior art like NL2030160B1 and others. ‘Complexity’ here stands forall means needed for translating motor motion (robot) or operator arm, wrist or finger movement (hand held) into the correct movement of steering wires / cables in the steerable instrument. For that reason, a detachable coupling between the disposable part and the reusable part is assumed to be needed at the level of the steering wires / cables itself, which in many cases is not technically viable. The current industry standard therefore is that robotic instruments generally have a connection box attached to the instrument body and hand held steerable instruments generally have a handle permanently attached to the instrument body.SUMMARY OF THE INVENTION

[0014] It is an object of the invention to provide a steerable instrument for endoscopic and / or invasive type of applications where at least one of the above mentioned problems are solved or at least reduced.

[0015] In a first aspect, this is achieved by a steerable instrument as claimed in the attached independent claim 1.

[0016] In such an instrument, the ‘complexity’ is divided over the single use instrument body and the reusable handle or robot such that the main requirements for an optimal solution are addressed. Moreover, more components of the steering unit than in the prior art are simple components made in the disposable instrument itself from a few tubes. The disposable instrument is easy to manufacture and is as compact as possible and requires a minimum of interfacing parts and secondly, an easy and fail safe detachable coupling that can be operated by the end user, on site, is established. The coupling may be to a hand-held control unit or to a robotic control unit.

[0017] A permanently attached connection box or handle can be omitted by transferring al required mechanisms needed for translating robot controller output or hand, wrist or finger movement into the desired distal tip movement, into the instrument body itself. Furthermore, production cost of such an instrument can potentially be so low that single use of these instruments is commercially viable. Another advantage is that the instrument dimensions are much smaller that the currently available instruments, which has an advantageous impact on transport and storage volume and the volume ofpackaging and instrument waste.

[0018] Advantageous embodiments are claimed in dependent claims.

[0019] A second aspect of the invention relates to compensating path length differences which may occur between adjacent steering wires, e.g., due to bending of the instrument body when the steerable instrument is inserted in a curved channel, e.g., intestines, blood vessels or bronchial tubes in a living being.

[0020] In instrument for this second aspect is claimed in independent claim 24 and advantageous embodiments are claimed in dependent claims.BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Further features and advantages of the invention will become apparent from the description of the invention by way of non-limiting and non-exclusive embodiments. These embodiments are not to be construed as limiting the scope of protection. The person skilled in the art will realize that other alternatives and equivalent embodiments of the invention can be conceived and reduced to practice without departing from the scope of the present invention. Moreover, separate features of different embodiments can be combined, even if not explicitly shown in the drawings or explained in the specification, unless such combination is physically impossible. The scope of the present invention is only limited by the claims and their technical equivalents. Embodiments of the invention will be described with reference to the figures of the accompanying drawings, in which like or same reference symbols denote like, same or corresponding parts, and in which:

[0022] Figure 1 shows a schematic cross sectional view of a distal section of a prior art invasive instrument assembly.

[0023] Figure 2 shows a schematic overview of distal portions of three prior art cylindrical elements from which the distal portion of Figure 1 may be manufactured.

[0024] Figure 3a shows a distal portion of a prior art intermediate cylindrical element of the instrument of Figures 1 and 2.

[0025] Figure 3b shows a distal portion of an alternative example of a prior art intermediate cylindrical element of such an instrument.

[0026] Figure 4 shows a distal portion of an example of a prior art intermediatecylindrical element and an inner cylindrical element inserted in the intermediate cylindrical element.

[0027] Figure 5 shows an outside view of a distal section of a prior art steerable invasive instrument assembly having two steerable bendable distal end portions and two proximal flexible control portions.

[0028] Figure 6 shows an enlarged view of the distal tip of the instrument shown in Figure 5.

[0029] Figure 7A shows a cross section view through the invasive instrument shown in Figure 5.

[0030] Figure 7B shows a distal end of an inner tube and intermediate tube of an alternative embodiment of a double bendable instrument in 3D view.

[0031] Figures 8 and 9 show examples of how the invasive instrument of Figures 5 and 7 can bend.

[0032] Figures 10-14 show some basic technologies that can be used to move one or more steering wires in the longitudinal direction.

[0033] Figures 15, 16A, 16B show arrangements that can be used to move one steering wire in the longitudinal direction by a tangentially rotatable tubeshaped element.

[0034] Figures 17, 18 A, 18B show arrangements that can be used to move two steering wires in opposite longitudinal directions by a tangentially rotatable tube-shaped element.

[0035] Figures 19, 20A, 20B show arrangements that can be used to move four steering wires in the longitudinal direction by two tangentially rotatable tubeshaped element.

[0036] Figures 21, 22A, 22B show arrangements that can be used to move two steering wires in opposite longitudinal directions by a tangentially rotatable tube-shaped element which is itself driven by a longitudinally shiftable element.

[0037] Figures 23, 24, 25 A, 25B, 26 show arrangements that can be used to move four steering wires in the longitudinal direction by two tangentially rotatable tube-shaped elements which are both driven by a tangentially rotatable and longitudinally shiftable element.

[0038] Figures 27, 28A-28D show arrangements that can be used to move four steering wires in the longitudinal direction by two tangentially rotatable tube-shaped elements which are both driven by an alternative tangentially rotatable and longitudinally shiftable element.

[0039] Figures 29A-29C show a gear arrangement.

[0040] Figures 30A, 30B, 31 show arrangements for longitudinally moving one or more sets of two adjacent longitudinal elements, like steering wires, by longitudinally moving a single longitudinal control element of which the longitudinal movement is controlled by one or more tangentially rotatable tubeshaped elements.

[0041] Figures 32A to 35 show some further gear arrangements.

[0042] Figures 36A-36C show an example of a coupling of a disposable instrument with two rotating tubes.

[0043] Figures 37 and 38, respectively, show a rotatable or slidable tubular interface of an instrument with spur gear teeth and worm drive gear teeth, respectively.

[0044] Figures 39A, 39B show schematic drawings to explain path length problems in of steering wires in multi-bendable instruments.

[0045] Figures 40-43 and 45 show examples of path length compensation solutions in schematic 2D form.

[0046] Figures 44A, 44B show schematic drawings to explain an example of a desired path length compensation solution in an instrument with two deflectable zones.

[0047] Figures 46A, 46B show an alternative path length compensation solution of an instrument with two deflectable zones.

[0048] Figures 47A-47E show an implementation of the schematic path length compensation solution of figure 45 as integrated in a steering wire drive mechanism in coaxial and axially aligned tubes.

[0049] Figures 48A-48E, 49A-49E, 50A-50E, and 51A-51E show an alternative path length compensation solution of an instrument with two deflectable zones.DETAILED DESCRIPTION OF EMBODIMENTS

[0050] For the purpose of the present document, the terms cylindrical element and tube may be used interchangeably, i.e., like the term tube a cylindrical element alsorefers to a physical entity. The invention will be explained with reference to steering wires which are cut from such cylindrical elements and are operative as push and / or pull steering wires to transfer longitudinal movement of the steering wires at the proximal end of the instrument to the distal end to thereby control bending of one or more flexible distal end portions. They have a strip like shape and, because they are cut from a tube, have a curved rectangular, cross section seen in the tangential direction of the steerable instrument.Steering mechanism.

[0051] Figures 1, 2, 3a, and 3b show distal portions of instruments known from W02009 / 112060. They are explained in detail because the present invention can be applied in this type of instruments.

[0052] Figure 1 shows a longitudinal cross-section of a distal section of a prior art steerable instrument 1 comprising three co-axially arranged cylindrical elements, i.e. inner cylindrical element 2, intermediate cylindrical element 3 and outer cylindrical element 4. Suitable materials to be used for making the cylindrical elements 2, 3, and 4 include stainless steel, cobalt-chromium alloys, shape memory alloy such as Nitinol®, plastic, polymer, composites or other materials that can be shaped by material removal processes like laser cutting or EDM. Alternatively, the cylindrical elements can be made by a 3D printing process or other known material deposition processes.

[0053] The inner cylindrical element 2 comprises a first rigid end part 5, which is located at a deflectable distal end part 13 of the instrument, a first flexible part 6, and an intermediate rigid part 7 located at an intermediate part 12 of the instrument.

[0054] The outer cylindrical element 4 also comprises a first rigid end part 17, a first flexible part 18, and an intermediate rigid part 19. The lengths of the parts 5, 6, and 7, respectively, of the cylindrical element 2 and the parts 17, 18, and 19, respectively, of the cylindrical element 4 are, preferably, substantially the same so that when the inner cylindrical element 2 is inserted into the outer cylindrical element 4, these different respective parts are longitudinally aligned with each other.

[0055] The intermediate cylindrical element 3 also has a rigid end part 10 which inthe assembled condition is located between the corresponding rigid parts 5 and 17 of the two other cylindrical elements 2, 4. An intermediate part 14 of the intermediate cylindrical element 3 comprises one or more separate steering wires 16 which can have different forms and shapes as will be explained below. They are made from the cylindrical element 3 themselves and have the form of a longitudinal strip. In figure 2, three such steering wires 16 are shown. After assembly of the three cylindrical elements 2, 3 and 4 whereby the element 2 is inserted in the element 3 and the two combined elements 2, 3 are inserted into the element 4 (any other order is possible), at least the first rigid end part 5 of the inner cylindrical element 2, the first rigid end part 10 of the intermediate cylindrical element 3 and the first rigid end part 17 of the outer cylindrical element 4 at the distal end of the instrument are attached to each other, e.g., by means of glue or one or more (laser) welding spots.

[0056] In the embodiment shown in figure 2 the intermediate part 14 of intermediate cylindrical element 3 comprises a number of steering wires 16 with a uniform cross-section so that the intermediate part 14 has the general shape and form as shown in the unrolled condition of the intermediate cylindrical element 3 in figure 3a. From figure 2 it also becomes clear that the intermediate part 14 is formed by a number of over the circumference of the intermediate cylindrical part 3, possibly equally, spaced parallel steering wires 16. Advantageously, the number of steering wires 16 is at least three, so that the instrument becomes fully controllable in any direction, but any higher number is possible as well. The number of steering wires 16 may, e.g., be four or eight.

[0057] It is observed that the steering wires 16 do not need to have a uniform cross section along their entire length. They may have a varying width along their length, possibly such that at one or more locations adjacent steering wires 16 are only separated by a small slot resulting from the laser cutting in the cylindrical element 3. These wider portions of the steering wires, then, operate as spacers to prevent adjacent steering wires 16 from buckling in a tangential direction in a pushed state. Spacers may, alternatively, be implemented in other ways.

[0058] An embodiment with spacers is shown in figure 3b which shows distal portions of two adjacent steering wires 16 in an unrolled condition. In the embodiment shown in figure 3b each steering wire 16 comprises portions 64 and62, co-existing with the first flexible part 6, 18 and the intermediate rigid part 7, 19, respectively. In the portion 62 coinciding with the intermediate rigid portion, each pair of adjacent steering wires 16 is almost touching each other in the tangential direction so that in fact only a narrow slot is present there between just sufficient to allow independent movement of each steering wire. The slot results from the manufacturing process and its width is, e.g., caused by the diameter of a laser beam cutting the slot.

[0059] In portion 61 each steering wire 16 consists of a relatively small and flexible part 64 as seen in circumferential direction, so that there is a substantial gap between each pair of adjacent flexible parts, and flexible part 64 is provided with a number of spacers 66, extending in the tangential direction and almost bridging completely the gap to the adjacent flexible part 64. Because of these spacers 66 the tendency of the steering wires 16 in the flexible portions of the instrument to shift in tangential direction is suppressed and tangential direction control is improved. The exact shape of these spacers 66 is not very critical, provided they do not compromise flexibility of flexible part 64. One or more spacers 66 are attached to flexible part 64 and form an integral part with the flexible part 64 and may result from a suitable laser cutting process too. They extend to an adjacent flexible part 64 of an adjacent steering wire 16.

[0060] In the embodiment shown in figure 3b the spacers 66 are extending towards one tangential direction as seen from the flexible part 64 to which they are attached. It is however also possible to have these spacers 66 extending to both circumferential directions starting from one flexible part 64. By using this it is either possible to have alternating types of flexible parts 64 as seen along the tangential direction, wherein a first type is provided at both sides with spacers 66 extending until the next flexible part, and a second intermediate set of flexible parts 64, without spacers 66. Otherwise it is possible to have flexible parts with cams at both sides, where as seen along the longitudinal direction of the instrument the cams originating from one flexible part are alternating with spacers originating from the adjacent flexible parts. It is obvious that numerous alternatives are available.

[0061] The production of such an intermediate part is most conveniently done by injection moulding or plating techniques or starting from a cylindrical tube with thedesired inner and outer diameters and removing parts of the wall of the cylindrical tube required e.g. by laser or water cutting to end up with the desired shape of the intermediate cylindrical element 3. However, alternatively, any 3D printing method can be used.

[0062] The removal of material can be done by means of different techniques such as laser cutting, photochemical etching, deep pressing, conventional chipping techniques such as drilling or milling, high pressure waterjet cutting systems or any suitable material removing process available. Preferably, laser cutting is used as this allows for a very accurate and clean removal of material under reasonable economic conditions. The above mentioned processes are convenient ways as the cylindrical element 3 can be made so to say in one process, without requiring additional steps for connecting the different parts of the intermediate cylindrical element as required in the conventional instruments, where conventional steering cables must be connected in some way to the end parts.

[0063] The same type of technology can be used for producing the inner and outer cylindrical elements 2 and 4 with their respective flexible parts 6, 18. These flexible parts 6, 18 can be manufactured as hinges resulting from cutting out any desired pattern from the cylindrical elements, e.g., by using any of the methods described in European patent application 08 004 373.0 filed on 10.03.2008, page 5, lines 15-26, but any other suitable process can be used to make flexible portions.

[0064] It is observed that the instrument portions shown in figures 4-9 are known from prior art W02020 / 214027. Also in these instruments the present invention can be applied.

[0065] Figure 4 shows an exemplary embodiment of longitudinal (steering) elements 16 that have been obtained after providing longitudinal slots 70 to the wall of the intermediate cylindrical element 3. Here, steering wires 16 are, at least in part, spiraling about a longitudinal axis of the instrument such that an end portion of a respective steering wire 16 at the proximal portion of the instrument is arranged at another angular orientation about the longitudinal axis than an end portion of the same steering wire 16 at the distal portion of the instrument. Were the steering wires 16 arranged in a linear orientation, then a bending of the instrument at the proximal portion in a certain plane would result in a bending of the instrument at the distal portion in the same plane but in a 180 degrees opposite direction. Thisspiral construction of the steering wires 16 allows for the effect that bending of the instrument at the proximal portion in a certain plane may result in a bending of the instrument at the distal portion in another plane, or in the same plane in the same direction. A preferred spiral construction may be such that the end portion of a respective steering wire 16 at the proximal portion of the instrument is arranged at an angularly shifted orientation of 180 degrees about the longitudinal axis relative to the end portion of the same steering wire 16 at the distal portion of the instrument. However, e.g. any other angularly shifted orientation, e.g. 90 degrees, is within the scope of this document. The slots 70 are dimensioned such that movement of a steering wire is guided by adjacent steering wires when provided in place in a steerable instrument. However, especially at the flexible zone 13 of the instrument, the width of steering wires 16 may be less to provide the instrument with the required flexibility / bendability at this location.

[0066] Figure 5 provides a detailed perspective view of the distal portion of an embodiment of an elongated tubular body 76 of a steerable instrument which has two deflectable distal deflectable zones 74, 75. Figure 5 shows that the elongated tubular body 76 comprises a number of co-axially arranged layers or cylindrical elements including an outer cylindrical element 104 that ends after a first distal flexible zone 74 at the distal end portion 13. The distal end portion 13 of the outer cylindrical element 104 is fixedly attached to a cylindrical element 103 located inside of and adjacent to the outer cylindrical element 104, e.g. by means of (laser) welding at welding spots 100. However, any other suitable attachment method can be used, including any mechanical snap fit connection or gluing by a suitable glue.

[0067] Figure 6 provides a more detailed view of the distal end part 13 and shows that, in this embodiment, it includes three co-axially arranged layers or cylindrical elements, i.e., an inner cylindrical element 101, a first intermediate cylindrical element 102 and a second intermediate cylindrical element 103. The distal ends of inner cylindrical element 101, first intermediate cylindrical element 102 and second intermediate cylindrical element 103 are all three fixedly attached to one another. This may be done by means of (laser) welding at welding spots 100. However, any other suitable attachment method can be used, including any mechanical snap fit connection or gluing by a suitable glue. The points of attachment may be at the end edges of inner cylindrical element 101, first intermediate cylindrical element 102and second intermediate cylindrical element 103, as shown in the figures. However, these points of attachment may also be located some distance away from these edges, be it, preferably, between the end edges and the locations of the flexible zone 75.

[0068] It will be clear to the skilled person that the elongated tubular body 76 as shown in figure 5 comprises four cylindrical elements in total. The elongated tubular body 76 according to the embodiment shown in figure 5 comprises two intermediate cylindrical elements 102 and 103 in which the steering members of the steering arrangement may be arranged. However, extra or less cylindrical elements may be provided if desired.

[0069] An exemplary actual arrangement of the steering members is shown in figure 7A, which provides a schematic longitudinal cross-sectional view of the exemplary embodiment of the elongated tubular body 76 as shown in figure 5.

[0070] Flexible zones 74, and 75 are, in this embodiment, implemented by providing the respective cylindrical elements with slits 74a, and 75a, respectively. Such slits 74a, and 75a may be arranged in any suitable pattern such that the flexible zones 74, and 75 have a desired flexibility in the longitudinal and tangential direction in accordance with a desired design.

[0071] Figure 7A shows a longitudinal cross section of the four layers or cylindrical elements mentioned above, i.e. the inner cylindrical element 101, the first intermediate cylindrical element 102, the second intermediate cylindrical element 103, and the outer cylindrical element 104.

[0072] The inner cylindrical element 101, as seen along its length from the distal end to the proximal end of the instrument, comprises a rigid ring 111, which is arranged at the distal end part 13 of the steerable instrument 10, a first flexible portion 112, a first intermediate rigid portion 113, a second flexible portion 114, and a second intermediate rigid portion 115.

[0073] The first intermediate cylindrical element 102, as seen along its length from the distal end to the proximal end of the instrument, comprises a rigid ring 121, a first flexible portion 122, a first intermediate rigid portion 123, a second flexible portion 124, and a second intermediate rigid portion 125. The portions 122, 123, 124, and 125 together form a steering wire 16(1) that can be moved in the longitudinal direction 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, and the second intermediate rigid portion 125 of the first intermediate element 102, respectively, are aligned with, and preferably approximately equal to the longitudinal dimensions of the rigid ring 111, the first flexible portion 112, the first intermediate rigid portion 113, the second flexible portion 114, and the second intermediate rigid portion 115 of the inner cylindrical element 101, respectively, and are coinciding with these portions as well. In this description “approximately equal” means that respective same dimensions are equal within a margin of less than 10%, preferably less than 5%.

[0074] Similarly, the first intermediate cylindrical element 102 comprises one or more other steering wires 16(2).

[0075] The second intermediate cylindrical element 103, as seen along its length from the distal end to the proximal end of the instrument, comprises a first rigid ring 131, a first flexible portion 132, a second rigid ring 133, a second flexible portion 134, and a first intermediate rigid portion 135. The portions 133, 134, and 135 and 136 together form a steering wire 130(1) that can be moved in the longitudinal direction like a wire. The longitudinal dimensions of the first rigid ring 131, the first flexible portion 132 together with the second rigid ring 133 and the second flexible portion 134 and the first intermediate rigid portion 135 of the second intermediate cylinder 103, respectively, are aligned with, and preferably approximately equal to the longitudinal dimensions of the rigid ring 111, the first flexible portion 112, the first intermediate rigid portion 113, the second flexible portion 114, and the second intermediate rigid portion 115 of the first intermediate element 102, respectively, and are coinciding with these portions as well.

[0076] Similarly, the second intermediate cylindrical element 103 comprises one or more other steering wires of which one is shown with reference number 130(2).

[0077] The outer cylindrical element 104, as seen along its length from the distal end to the proximal end of the instrument, comprises a first rigid ring 141, a first flexible portion 142, and a first intermediate rigid portion 143. The longitudinal dimensions of the first flexible portion 142 and the of the outer cylindrical element 104, respectively, are aligned with, and preferably approximately equal to the longitudinal dimension of the second flexible portion 134 and the first intermediate rigid portion 135 of the second intermediate element 103, respectively, and arecoinciding with these portions as well. The rigid ring 141 may have approximately the same length as the rigid ring 133 and is fixedly attached thereto, e.g. by spot welding or gluing. The rigid rings 111, 121 and 131 are attached to each other, e.g., by spot welding or gluing. This may be done at the end edges thereof but also at a distance of these end edges.

[0078] The inner and outer diameters of the cylindrical elements 101, 102, 103, and 104 are chosen in such a way at a same location along the elongated tubular body 76 that the outer diameter of inner cylindrical element 101 is slightly less than the inner diameter of the first intermediate cylindrical element 102, the outer diameter of the first intermediate cylindrical element 102 is slightly less than the inner diameter of the second intermediate cylindrical element 103 and the outer diameter of the second intermediate cylindrical element 103 is slightly less than the inner diameter of the outer cylindrical element 104, in such a way that a sliding movement of the adjacent cylindrical elements with respect to each other is possible. The dimensioning should be such that a sliding fit is provided between adjacent elements. A clearance between adjacent elements may generally be in the order of 0.02 to 0.1 mm, but depends on the specific application and material used. The clearance may be smaller than a wall thickness of the steering wires to prevent an overlapping configuration thereof. Restricting the clearance to about 30% to 40% of the wall thickness of the steering wires is generally sufficient.

[0079] The use of the construction as described above allows the steerable instrument 10 to be used for double bending. The working principle of this construction will be explained with respect to the examples shown in figures 8 and 9.

[0080] For the sake of convenience, as shown in figures 7 A, 8 and 9, the different portions of the cylindrical elements 101, 102, 103, and 104 have been grouped into zones 151 - 155 that are defined as follows. Zone 151 comprises the rigid rings 111, 121, and 131. Zone 152 comprises the portions 112, 122, and 132. Zone 153 comprises the rigid rings 133 and 141 and the portions 113 and 123. Zone 154 comprises the portions 114, 124, 134 and 142. Zone 155 comprises the portions 115, 125, 135 and 143.

[0081] By pushing / pulling steering wires 130(1), 130(2) in the longitudinal direction of the instrument, one side of the attached rigid rings 133 / 141 can bemoved either in the proximal or distal direction of the instrument, whereas at the opposing tangential side of the instrument these attached rigid rings 133 / 141 can be moved in the opposite direction, resulting in a deflection of the instrument of deflectable zone 154, as shown in figure 8.

[0082] When three or more steering wires per set I30(j) (j = 1, 2, 3, ... J), preferably equally tangentially spaced, are applied deflectable zone 154 can be deflected in any desired direction.

[0083] By pushing / pulling steering wires 16(1), 16(2) in the longitudinal direction of the instrument, one side of the attached rigid rings 121 / 131 can be moved either in the proximal or distal direction of the instrument, whereas at the opposing tangential side of the instrument these attached rigid rings 121 / 131 can be moved in the opposite direction, resulting in a deflection of the instrument of deflectable zone 154, as shown in figure 8.

[0084] When three or more steering wires per set 16(i), preferably equally tangentially spaced, are applied deflectable zone 152 can be deflected in any desired direction.

[0085] Due to the fact that zones 152 and 154 are deflectable independently with respect to each other, it is possible to give the distal end part 13 of the steerable instrument a position and longitudinal axis direction that are independent from each other. In particular the distal end part 13 can assume an advantageous S-like shape. The skilled person will appreciate that the capability to independently deflect zones 152 and 154 with respect to each other, significantly enhances the manoeuvrability of the distal end part 13 and therefore of the steerable instrument as a whole.

[0086] Obviously, it is possible to vary the lengths of the flexible portions shown in figures 7A to 9 as to accommodate specific requirements with regard to bending radii and total lengths of the distal end part 13 and the proximal end part 11 of the steerable instrument.

[0087] In the shown embodiment, the steering wires comprise one or more sets of steering wires that form integral parts of the one or more intermediate cylindrical elements 102, 103. Preferably, the steering wires comprise remaining parts of the wall of an intermediate cylindrical element 102, 103 after the wall of the intermediate cylindrical element 102, 103 has been provided with longitudinal slits that define the remaining steering wires.

[0088] Whereas in figures 7A, 8, 9 an embodiment is shown in which steering wires 16(1), 16(2) for deflecting the most distal deflectable zone 75 are made in another tube than steering wires 130(1), 130(2) for deflecting deflectable zone 74, all such steering wires can be made in one single tube as shown in figure 7B, in which reference numbers 130 are substituted by reference numbers 16. Figure 7B shows four steering wires 16(1) - 16(4) of a total of eight steering wires all made in tube 102. Figure 7B shows how rigid rings 111 and 121 are attached to another at one or more attachment points 170, e.g. by (laser) welding or gluing, etc. It also shows that steering wires 16(1) and 16(3) are attached to rigid ring 121 (the same is true for steering wires 16(5) and 16(7) but they are not visible in figure 7B). The distal ends of steering wires 16(2), 16(4) (as well as 16(6) and 16(8)) are attached to intermediate rigid portion 113 at attachment points 172, e.g. by (laser) welding or gluing, etc.

[0089] By pulling / pushing steering wires 16(1), 16(3), 16(5), 16(7) one can deflect flexible portion 112 and by pulling / pushing steering wires 16(2), 16(4), 16(6), 16(8) one can deflect flexible portion 114, as one will understand based on the above explanations.

[0090] Steering unit

[0091] The following describes embodiments of instruments, hand held and robotic actuators, and coupling methods that improve cost effectiveness and enable single use of instruments and therefor reduction of the occurrence of post operative complications associated with re-use of instruments. Furthermore, the volume of the disposable instruments is significantly reduced which has a desirable effect on storage and shipment volume and the volume of waste.

[0092] The following embodiments show instruments and handles and robot interfaces in which the ‘complexity’ is divided over the single use instrument and the reusable handle or robot such that the main requirements for an optimal solution are addressed. Firstly, the disposable instrument is easy to manufacture and is as compact as possible and requires a minimum of interfacing parts and secondly, an easy and fail safe detachable coupling that can be operated by the end user, on site, is established.

[0093] An instrument can be manufactured as proposed in W02009 / 112060,WO2009 / 127236, WO2012128618, WO201217335a8, W02014011049, WO2015084174, W02016089202, W02017010883, WO2017014624, W02017082720, WO2017213491, W02018067004, W02019009710, W02020080938, W02020214027, W02020218920, WO2020218921, WO2022260518, and WO2023287286. These applications propose an instrument in which the required parts and features are manufactured by laser cutting the parts out of the walls of one or more tubes and leave them in a pre-assembled state. The only additional manufacturing step is to slide a number of tubes into each other and attach the layers of tubes to each other at the required locations. Once one has this method in place it is very easy and almost without additional cost, to also laser cut additional parts in the same layers of tubes.

[0094] For example, WO2022260518 shows mechanisms that are used for length compensation of longitudinal members in the instrument body, for preventing that the instrument distal tip is actuated (bent) when a flexible instrument body is guided through a curved channel. WO2022260518 describes the use of tube parts, containing slots and sliding members for that purpose. As will be explained hereinafter, one can also use slots and sliding members for direct or indirect actuation of steering wires and / or other longitudinal control elements for other purposes in a steerable instrument.

[0095] US2015 / 0107396 shows that a steering wire can be actuated by a groove, but this application only shows a conventional solution, in which the instrument and the handle are assembled from many individual parts and in which the handle is permanently attached to the instrument body. US2015 / 0107396 also only shows actuation elements, containing the grooves for steering wire actuation, that have a rotation axis that intersects with the longitudinal axis of the instrument body. Furthermore, US2015 / 0107396 is limited to an instrument of which the distal part can only be bent in two directions in one bending plane.

[0096] The following describes examples of solutions in which the permanent attachment of a hand held handle or a connection box can be avoided, by making the coupling between individual steering wires to an actuation means such that it can be done by an end user on site.

[0097] Figure 10 shows an embodiment of an instrument having three - whichin practise can be more - coaxial tubes, i.e., inner tube 2, an intermediate tube in which steering wires 16(i) are made, and an outer tube 203. The instrument has a centre axis 229. Each proximal end portion of steering wire 16(i) is provided with one or more pins 221 (i) radially extending from the instrument through a longitudinal slot 205 (i) in outer tube 203. The one or more pins 221 (i) are fixed to steering wire 16(i). Each such pin 221 (i) can be connected or attached to a suitable driving component in order to move the individual steering wires 16(i) to deflect the deflectable tip portion of the instrument. The driving component may be manually controlled or controlled by a robotic device.

[0098] Figure 11 shows an embodiment of a steering unit of an instrument provided with four steering wires 16(i), though any other suitable number may be used instead. Outer tube 203 is provided with four longitudinal slots 205(i), each one tangentially aligned with one steering wire. However, these four different longitudinal slots 205 (i) are longitudinally off-set relative to one another. Per longitudinal slot 205(i) a ring 223(i) is provided with an inner diameter slightly larger than an outside diameter of outer tube 203 such that ring 223(i) can axially slide along outer tube 203. Moreover, each ring 223(1) is attached to an associated steering wire 16(i) via longitudinal slot 205(i), e.g., by means of a pin-shaped component like pin 221 (i) shown in figure 10. Each ring 223(i) has a radially extending pin 225(i). Each such ring 223(i) or pin 225(i) can be connected or attached to a suitable driving component in order to move the individual steering wires 16(i) to deflect the deflectable tip portion of the instrument. The driving component may be manually controlled or controlled by a robotic device.

[0099] Figure 12 shows a variant to the embodiment of the steering unit of figure 11. Here, rings 223(i) with extending pins 225(i) are substituted by rings 227(i) with two radially extending flanges 228(i) per ring 227(i). The two flanges 228(i) are arranged at a predetermined longitudinal distance from one another such that together with ring 227(i) they define a circumferential groove. Again outer tube 203 is provided with four - or any other suitable number of - longitudinal slots 205 (i), each one tangentially aligned with one steering wire 16(i), which longitudinal slots 205 (i) are longitudinally off-set relative to one another. Each ring 227(i) has an inner diameter slightly larger than the outsidediameter of tube 203 such that ring 227(i) can slide along outer tube 203. Moreover, each ring 227(1) is attached to an associated steering wire 16(i) via longitudinal slot 205(i), e.g., by means of a pin shaped component like pin 221 (i) shown in figure 10 or another means of attachment like welding or bolts / screws.

[0100] To allow coupling to a controller, such a controller may be provided with sliders configured to be inserted into the grooves defined by rings 227(i) and flanges 228(i) such that any longitudinal movement of the sliders inside the controller results in a longitudinal movement of the steering wires 16(i). The controller may have as many sliders as there are steering wires 16(i) to allow independent control of the steering wires 16(i). Such circumferential grooves ease alignment between each slider and an associated steering wire 16(i) because only longitudinal alignment is required. The tangential alignment is, in this embodiment, taken care of by the groove defined by ring 227(i) and flanges 228(i). Moreover, once coupled to a controller, the instrument can be freely rotated relative to the controller because the sliders will stay in their associated groove defined by ring 227(i) and flanges 228(i).

[0101] Figures 13 A and 13B show an embodiment of a steering unit with rings 231 (i) having a screw thread 233(i) inside. Figures 13A and 13B show only one such ring 231(1), however, there will be one ring 23 l(i) per steering wire 16(i). Outer tube 203 is provided with a screw thread 234(i) per steering wire 16(i), longitudinally aligned with longitudinal slot 205 (i). Screw thread 233 (i) of each ring 23 l(i) is screwed on screw thread 234(i) on outer tube 203. A pin 221(i) is attached to steering wire 16(i), which pin 221 (i) extends through longitudinal slot 205(i) into a circumferential groove 232(i) inside ring 23 l(i). A pin 236(i) is provided on the outer surface of ring 23 l(i). Figure 13B is a cross sectional view through a plane through a centre line XIII through longitudinal slot 205 (i) and centre axis 229.

[0102] Rotating ring 23 l(i) about outer tube 203 causes ring 23 l(i) to move in the longitudinal direction of instrument 1. Then, groove 232(i) rotates about pin 221 (i) causing pin 221 (i) and thus steering wire 16(i) to also move in the longitudinal direction of the instrument. A controller is implemented to be connected to pin 236(i) such that it is configured to rotate ring 23 l(i) to movesteering wire 16(i) in its longitudinal direction.

[0103] As an alternative to pin 236(i) the outside surface of ring 23 l(i) may be provided with a tooth shaped structure configured to cooperate with a suitable drive wheel inside a controller, cf. figure 37. Also, as a further alternative, a worm gear construction may be used to drive rotation of ring 23 l(i), cf. figure 38.

[0104] Figure 14 shows a further alternative of a possible coupling mechanism between the steering wires 16(i) and a controller. Here, steering wires 16(i) are provided with a set of one or more consecutive openings 235 (i). Instead of openings 235(i) grooves or teeth like structures may be used, for example, an involute geared cam might be used with a corresponding involute geared wheel. For each steering wire 16(i) the controller is provided with a gear 237(i). Coupling of the instrument can be accomplished by having the gears 237(i) in a correct fixed radial position to engage with the openings 235(i) or the toothed cam on the end of the steering wire 16(i). When one de-couples the gears 237(i) from the drive motor such that they can rotate freely, for example with a mechanical or electro mechanical clutch, one can insert the instrument until the gears 237(i) and steering wire ends are fully engaged. At that moment the gear clutch can be engaged and the gears can be driven by the actuator motor. One could also choose to have the gears attached to a slider with a preloaded radial force, with which the gears can be opened and closed radially. Engaging the teeth of the gears and the steering wires 16(i) can be accomplished by rotating the gears till they engage. In the coupled state between the instrument and the controller every gear 237(i) is arranged and configured to cooperate with the set of one or more consecutive openings 235(i) of steering wire 16(i). Longitudinal movement of steering wires 16(i) can be controlled on an individual basis.

[0105] The previous examples of figures 10-14 show simple solutions for attachment of individual steering wires with easy to couple features with which individual steering wires can be coupled to actuation means, like for example robot actuation with linear or rotating motors. Disadvantage of these solutions may be that they require individually manufactured and assembled parts. Furthermore, each individual steering wire coupling means has to be actuated by an individual actuation means in the robot or the hand held handle.

[0106] Other, alternative solutions that require less individually manufactured parts and less actuator inputs are presented below. Moreover, these parts can all be manufactured from one or more tubes by providing these tubes with one or more suitable material removal patterns.

[0107] One alternative method to actuate a single steering wire 16(1) is shown schematically in figure 15. A sliding member 301(1) is configured in the steering unit such that it can only be moved up and down. Sliding member 301(1) has a slitshaped opening 303(1) and the steering wire 16(1) is provided with a pin 305(1) accommodated in slit-shaped opening 303(1). Slit-shaped opening 303(1) is arranged at an angle a to longitudinal direction of steering wire 16(1) such that 0 < a < 90 degrees. When sliding member 301(1) is moved downward as indicated with an arrow Fl, steering wire 16(1) moves to the right, as indicated with an arrow F2, in the direction of the longitudinal axis of the instrument. When sliding member 301 is moved upward, steering wire 16(1) moves to the left.

[0108] Figures 16A and 16B show an embodiment of how the steering unit of figure 15 can be incorporated in the instrument as a very easy to make and compact solution, assuming one practices manufacturing methods as described in W02009 / 1 12060, WO2009 / 127236, WO2012128618, WO2012173478, W0201401 1049, WO2015084174, W02016089202, W02017010883, WO2017014624, W02017082720, WO2017213491, W02018067004, WO20 19009710, W02020080938, W02020214027, W02020218920, WO2020218921, WO2022260518, and WO2023287286. The embodiment of figures 16 A, 16B can be made by making suitable material removal patterns in four tubes. In figures 16A, 16B, all components with a reference number with an affix “a” have the same function as the component with the same reference number without affix “a” in figure 15.

[0109] The intermediate tube has, e.g., four steering wires 16(i) and the mechanism of figure 15 is shown to be applied to one of them. Outer tube 203 is provided with longitudinal slots 309(i) - one for each steering wire 16(i) - which are tangentially aligned with respective steering wires 16(i). A sliding pin 307(i) is provided in longitudinal slot 309(i). Sliding pin 307(i) is attached to steering wire 16(i) and can move freely in the longitudinal direction of longitudinal slot 309(i). I.e., sliding pin 307(i) is guided in the longitudinal direction by longitudinal slot 309(i) and canonly move in the desired steering wire direction.

[0110] Only one additional tube needs to be added about outer tube 203 to complete the steering mechanism. A distal ring 321 made from this additional tube is attached to outer tube 203 at a distal location from longitudinal slot 309(i), and a proximal ring 323 is attached to outer tube 203 at a proximal location from longitudinal slot 309(i).

[0111] As shown in figure 16B, the additional tube includes a control tube portion 301a(i) containing a helical slot 303a(i) and a sliding pin 305a(i) inside helical slot 303a(i). Control tube portion 301a(i) can rotate about outer tube 203 between distal ring 321 and proximal ring 323 but cannot move in the longitudinal direction between distal ring 321 and proximal ring 323 - apart from some possible play resulting from the manufacturing process. Sliding pin 305a(i) is attached to sliding pin 307(i) in outer tube 203, such that also sliding pin 305a(i) is attached to steering wire 16(i). When control tube portion 301a(i) is rotated around the coaxially arranged instrument, helical slot 303a(i) will actuate both sliding pins 307(i) and 305a(i) in a longitudinal direction. In this way, a simple, compact and easy to manufacture solution is created for attaching individual steering wires to a simple to couple element that can be rotated by for example an electric actuation motor in a robot arm directly.

[0112] The mechanism does not need to be manufactured as separate parts that require individual assembly, but now it can be, for example, (laser) cut integrally and pre-assembled in some tubes, as is, e.g., described in W02016089202. Pins 305a(i) are made from tube 321 / 323, 307(i) are made from tube 203, e.g., by (laser) cutting or any other material removing technique. Methods of how to establish the connection between the rotatable control tube portion 301a(i) and such a motor, or a rotation actuation element in a hand held handle will be described further down in the present document.

[0113] For each steering wire 16(i) a separate steering mechanism including rings 321, 323 and control tube portion 301a(i) can be provided in order to provide separate steering control for all steering wires 16(i). However, control tube portion 301a(i) can be arranged to control longitudinal movement of more than one steering wire 16(i). This is, e.g., possible because in practise the instrument may be designed such that each steering wire 16(i) has an opposite steering wire, i.e., at a 180degrees tangentially rotated location in the instrument. In such a configuration, two opposite steering wires 16(i) when they are operated to deflect the deflectable tip move along identical distances be it in opposite longitudinal directions.

[0114] If one applies the principle of figures 16A, 16B one can also envision an embodiment as shown in figure 17. In figure 17 the same reference numbers as used in figure 15 refer to the same components. In addition to figure 15, figure 17 shows two steering wires 16(1), 16(3). It is assumed that steering wire 16(3) is located at a 180 degrees tangentially rotated location relative to steering wire 16(1). The steering unit contains one single sliding member 302(1,3) with slit-shaped opening 303(1) for steering wire 16(1) and an extra slit-shaped opening 303(3) for steering wire 16(3). A pin 305(3) is attached to steering wire 16(3) and accommodated in slit-shaped opening 303(3). Slit-shaped opening 303(3) is arranged at an angle 13 relative to its longitudinal axis. In most practical cases a = 13. When one now moves sliding member 302(1,3) down, as indicated with arrow Fl, steering wire 16(1) will move in the right direction, as indicated with arrow F2, and steering wire 16(3) will move in the left direction, as indicated with arrow F3. If a = 13, steering wires 16(1), 16(3) will move along the same length be it in opposite directions such that one of them is generating a pulling force and the other one is developing a pushing force, thus causing the tip to deflect. The two steering wires 16(1), 16(3) are actuated simultaneously by one control element.

[0115] Figures 18 A, 18B show an implementation of the steering unit of figure 17 in an instrument manufactured from some tubes and in which two steering wires can move the instrument tip in two directions, in one plane, when the slots are configured such that they move the two actuated steering wires in opposite directions. Of course, the slots can be shaped such that one can establish any desired actuation direction and magnitude, when the tube containing the slots is rotated. The embodiment of figures 18 A, 18B can be made by making suitable material removal patterns in four tubes. In figures 18 A, 18B all components with a reference number with an affix “a” have the same function as the component with the same reference number without affix “a” in figure 17.

[0116] As shown in figure 18A, the intermediate tube 3 has, e.g., four equidistant steering wires 16(i). Outer tube 203 is provided with longitudinal slots 309(i) - one for each steering wire 16(i) - which are tangentially aligned with respectivesteering wires 16(i). A sliding pin 307(i) is provided in longitudinal slot 309(i). Sliding pin 307(i) is attached to steering wire 16(i) and can move freely in the longitudinal direction of longitudinal slot 309(i). I.e., sliding pin 307(i) is guided in the longitudinal direction by longitudinal slot 309(i) and can only move in the desired steering wire direction.

[0117] Steering wire 16(3), longitudinal slot 309(3), and sliding pin 307(3) are explicitly shown in figure 18A. Steering wire 16(1) is located opposite, i.e., at a 180 degrees tangentially rotated location, to steering wire 16(3) and not visible in figure 18A. Outer tube 203 has a longitudinal slot 309(1) with sliding pin 307(1) located on the opposite side but also closer to the proximal (right) end of the instrument than longitudinal slot 309(3).

[0118] Only one additional tube needs to be added about outer tube 203 to complete the steering mechanism for steering wires 16(1), 16(3). A first ring 321 made from this additional tube is attached to outer tube 203 at a distal location from longitudinal slot 309(3), and a second ring 323 is attached to outer tube 203 at a proximal location from longitudinal slot 309(1).

[0119] As shown in figure 18B, the additional tube includes a control tube portion 302a(l,3) containing a helical slot 303a(3) and a sliding pin 305a(3) inside helical slot 303a(3). The control tube portion 302a(l,3) also contains a helical slot 303a(l) and a sliding pin 305a(l) [not visible] inside helical slot 303a(l). Helical slots 303a(l) and 303a(3) are spiraling in opposite directions. Control tube portion 302a(l,3) can rotate about outer tube 203 between first ring 321 and second ring 323 but cannot move in the longitudinal direction between first ring 321 and second ring 323 - apart from some possible play resulting from the manufacturing process. Sliding pins 305a(l) and 305a(3), respectively, are attached to sliding pins 307(1) and 307(3), respectively, in outer tube 203, such that also sliding pins 305a(l) and 305a(3), respectively, are attached to steering wires 16(1) and 16(3), respectively. When control tube portion 302a(l,3) is rotated around the coaxially arranged instrument, as indicated with reference number Rl, helical slots 303a(l) and 303a(3), respectively, will actuate both the attached sliding pins 307(1) and 305a(l), and the attached sliding pins 307(3) and 305a(3), respectively, in a longitudinal but opposite way, of which the principles were explained with reference to figure 17.

[0120] In this way, a simple, compact and easy to manufacture solution is created for attaching pairs of individual steering wires to a single and simple to couple element that can be rotated by for example an electric actuation motor in a robot arm directly. The mechanism does not need to be manufactured as separate parts that require individual assembly, but now it can be, for example, (laser) cut integrally and pre-assembled in some tubes, as is, e.g., described inWO20 16089202. Methods of how to establish the connection between the rotatable control tube portion 302a(l,3) and such a motor, or a rotation actuation element in a hand held handle will be described further down in this document.

[0121] Figure 19 shows an example of a steering unit that one obtains when two of the mechanisms as shown in figure 17 with a single control tube portion are used to control longitudinal movements of two pairs of opposite steering wires 16(i).

[0122] In this way, one can actuate a second pair of steering wires 16(i), that for example steer the tip in a plane perpendicular to the first steering plane associated with the first pair of steering wires 16(i), with a second rotatable control tube portion. One can add a steering mechanism for a second pair of steering wires 16(i) easily and without significant extra costs or effort when one cuts a second assembly of the mechanism as in figures 18 A, 18B in the same piece of the additional tube located around outer tube 203. This will only add a limited length of additional tube with very low material cost and will only increase the (laser) cutting time with a few seconds.

[0123] In figure 19, all reference numbers which are the same as in figure 17 relate to the same components. The extra reference numbers are explained now.

[0124] In addition to figure 17, figure 19 shows two steering wires 16(2), 16(4). It is assumed that steering wire 16(4) is located at a 180 degrees tangentially rotated location relative to steering wire 16(2). The mechanism contains a further sliding member 302(2,4) with slit-shaped opening 303(2) for steering wire 16(2) and an extra slit-shaped opening 303(4) for steering wire 16(4). A pin 305(2), 305(4), respectively, is attached to steering wire 16(2), 16(4), respectively, and accommodated in slit-shaped opening 303(2), 303(4), respectively. Slit-shaped opening 303(2), 303(4), respectively, is arranged at an angle y, 5, respectively, relative to its longitudinal axis, respectively. In most practical cases a = 13 = y = 5. When one now moves sliding member 302(2,4) down, as indicated with arrow F6,steering wire 16(4) will move in the right direction, as indicated with arrow F5, and steering wire 16(2) will move in the left direction, as indicated with arrow F4. If y = 5, steering wires 16(2), 16(4) will move along the same length be it in opposite directions such that one of them is generating a pulling force and the other one is developing a pushing force, thus causing the tip to deflect. The two steering wires 16(2), 16(4) are actuated simultaneously.

[0125] Figures 20A, 20B show an implementation of the steering unit of figure 19 in an instrument manufactured from some tubes and in which four steering wires can move the instrument tip in all directions. Of course, the slots can be shaped such that one can establish any desired actuation direction and magnitude, when the tube containing the slots is rotated. The embodiment of figures 20A, 20B can be made by making suitable material removal patterns in four tubes. In figures 20A, 20B all components with a reference number with an affix “a” have the same function as the component with the same reference number without affix “a” in figure 19.

[0126] As shown in figure 20A, the intermediate tube 3 has, e.g., four equidistant steering wires 16(i). Outer tube 203 is provided with longitudinal slots 309(i) - one for each steering wire 16(i) - which are tangentially aligned with respective steering wires 16(i). So, the longitudinal slots 309(i) are also located at tangentially equidistant locations. A sliding pin 307(i) is provided in longitudinal slot 309(i). Sliding pin 307(i) is attached to steering wire 16(i) and can move freely in the longitudinal direction of longitudinal slot 309(i). I.e., sliding pin 307(i) is guided in the longitudinal direction by longitudinal slot 309(i) and can only move in the desired steering wire direction.

[0127] Steering wires 16(3), 16(4), longitudinal slots 309(3), 309(4), and sliding pin 307(3), 307(4) are explicitly shown in figure 20A. Steering wires 16(1), 16(2), respectively, are located opposite, i.e., at a 180 degrees tangentially rotated location, to steering wires 16(3), 16(4), respectively, and not visible in figure 20A. Outer tube 203 has longitudinal slot 309(1) with sliding pin 307(1) located on the opposite side but also closer to the proximal (right) end of the instrument than longitudinal slot 309(3) and longitudinal slot 309(2) with sliding pin 307(2) located on the opposite side but also closer to the proximal (right) end of the instrument than longitudinal slot 309(4).

[0128] Only one additional tube needs to be added around outer tube 203 to complete the steering mechanism for steering wires 16(i). The arrangement with first ring 321 and ring 323 is the same as in figures 18 A, 18B made from this additional tube. The embodiment of figures 20A, 20B includes a third ring 327 attached to outer tube 203 at a proximal location from second ring 323 and from longitudinal slots 309(2), 309(4).

[0129] Like in figures 18A, 18B longitudinal slots 309(1), 309(3) and sliding pins 307(1), 307(3) are located between first ring 321 and second ring 323. Longitudinal slots 309(2), 309(4) and sliding pins 307(2), 307(4) are located between second ring 323 and third ring 327.

[0130] In figures 20A, 20B the arrangement of control tube portion 302a(l,3), steering wires 16(1), 16(3), first ring 321, second ring 323, longitudinal slots 309(1), 309(3), sliding pins 307(1), 307(3), and helical slots 303a(l), 303a(3) is the same as in figures 18 A, 18B.

[0131] As shown in figure 20B, the additional tube includes a further control tube portion 302a(2,4) containing a helical slot 303a(4) and a sliding pin 305a(4) inside helical slot 303a(4). The further control tube portion 302a(2,4) also contains a helical slot 303a(2) and a sliding pin 305a(2) [not visible] inside helical slot 303a(2). Helical slots 303a(2) and 303a(4) are spiraling in opposite directions. Further control tube portion 302a(2,4) can rotate about outer tube 203 between second ring 323 and third ring 327 but cannot move in the longitudinal direction between second ring 323 and third ring 327 - apart from some possible play resulting from the manufacturing process. Sliding pins 305a(2) and 305a(4), respectively, are attached to sliding pins 307(2) and 307(4), respectively, in outer tube 203, such that also sliding pins 305a(2) and 305a(4), respectively, are attached to steering wires 16(2) and 16(4), respectively. When further control tube portion 302a(2,4) is tangentially rotated around the coaxially arranged instrument, helical slots 303a(2) and 303a(4), respectively, will actuate both sliding pins 307(2) and 305a(2), and 307(4) and 305a(4), respectively, in a longitudinal but opposite way, of which the principles were explained with reference to figure 19.

[0132] In this way, a simple, compact and easy to manufacture solution is created for attaching pairs of individual steering wires to a simple to couple element that can be rotated by for example an electric actuation motor in a robot arm directly.The two control tube portions 302a(l,3), 302a(2,4) can be tangentially rotated individually to steer the instrument tip in any direction. The mechanism does not need to be manufactured as separate parts that require individual assembly, but now it can be, for example, laser cut integrally and pre-assembled in some tubes, as is, e.g., described in WO2016089202. Methods of how to establish the connection between the rotatable further control tube portion 302a(2,4) and such a motor, or a rotation actuation element in a hand held handle will be described further down in this document.

[0133] Furthermore, as compared to the embodiments described in figures 10-14, the number of required actuators is reduced. Steering of an instrument tip in any direction can now be accomplished by only two rotating actuation means, instead of four individual mechanisms that one would need for accomplishing tip steering in any direction, with embodiments described in figures 10-14.

[0134] Sometimes, however, it might be practical to actuate tip steering with a translation means instead of a rotating means. For example, one can imagine, that in a hand held handle one would like to steer the tip with a sliding knob. In that case it would be beneficial to incorporate a sliding tube instead of a rotating tube to establish tip steering. Figure 21 schematically shows a steering unit that actuates two steering wires as a reaction on sliding one element in a longitudinal direction.

[0135] In figure 21 the same reference numbers as used in figure 17 refer to the same components. The principle schematic arrangement of figure 21 includes a longitudinally sliding member 331 which can be moved back and forth in the longitudinal direction as indicated with arrow F6. Longitudinal sliding member 331 includes a slit-shaped opening 335 and the sliding member 302(1,3) is provided with a pin 333 accommodated in slit-shaped opening 335. Slit-shaped opening 335 is arranged at an angle a to longitudinal direction of steering wire 16(1) such that 0 < a < 90 degrees. When sliding member 331 is moved back or forth in its longitudinal direction, sliding member 301 is forced to moved upward / downward as indicated with arrow Fl, and steering wires 16(1), 16(3) are forced to move back or forth in the longitudinal direction as indicated with arrow F2, F3 in the direction of the longitudinal axis of the instrument.

[0136] Like in figure 17, steering wires 16(1), 16(3) will move along the same length be it in opposite directions such that one of them is generating a pulling forceand the other one is developing a pushing force, thus causing the tip to deflect. The two steering wires 16(1), 16(3) are actuated simultaneously.

[0137] Figures 22A, 22B show an embodiment in which the principles of figure 21 are implemented. The steering unit arrangement of figures 18 A, 18B contains the entire instrument of figures 20A, 20B, as is shown in figure 22A. In addition to the components shown in figures 18 A, 18B, the instrument includes a longitudinal slider 331a which is configured to actuate rotation of the control tube portion 302a(l,3) by longitudinal movements F6. In figures 22A, 22B all components with a reference number with an affix “a” have the same function as the component with the same reference number without affix “a” in figure 21.

[0138] To that end, in the shown example, longitudinal slider 331a is provided with a longitudinal extension 343 which extends into a longitudinal slot 339 of a fourth ring 337. The width of slot 339 matches the width of longitudinal extension 343 such that longitudinal extension 343 can only move in the longitudinal direction of slot 339 and not in the tangential direction. Moreover, fourth ring 337 is attached such that it cannot rotate relative to outer tube 203. To that end, it may be directly attached to outer tube 203, e.g. by (laser) welding or to first ring 321 which is attached to outer tube 203. As a person skilled in the ort will understand, there are many other possible mechanisms to prevent longitudinal slider 331a from rotation relative to outer tube 203.

[0139] In an embodiment, fourth ring 337 may have an inner diameter such that it matches the outer diameter of outer tube 203 and can be directly attached to outer tube 203. Alternatively, fourth ring 337 may have an inner diameter such that matched the outer diameter of first ring 321 such that can be attached to first ring 321. In this latter example, fourth ring 337 and longitudinal slider 331a can be made from a further additional tube by providing that further additional tube with a suitable material removal pattern. That further additional tube is coaxial with and longitudinally aligned with the additional tube from which the components 321, 302a(l,3), 305a(l), 305a(3), 303a(l), 303a(3), and 323 are made.

[0140] Longitudinal slider 33 la is provided with a helical slot 335a and a sliding pin 333a which is located inside helical slot 335a. Sliding pin 333a is attached to control tube portion 302a(l,3). Therefore, sliding pin 333a cannot move in a longitudinal direction and can only move in a tangential direction. In use, slidingpin 333a is forced to rotate in a tangential direction by moving longitudinal slider 331a in the longitudinal direction F6. This will cause control tube portion 302a(l,3) to rotate tangentially and, as a consequence, the deflectable tip is deflected by opposite longitudinal movements of steering wires 16(1), 16(3).

[0141] In this way a normally more complex mechanism, made from individually manufactured and assembled parts is again transformed to an easy, cheap and preassembled mechanism by the simple addition of one extra tube. I.e., pin 333a can be made from the tube 33 la / 343, e.g., by (laser) cutting or any other material removing technique. In a further embodiment, one can incorporate two of the mechanisms as shown in figures 22A, 22B in the instrument, such that deflection of the tip in all directions, could be established by two linear actuators instead of two rotating actuators. To that end, an arrangement similar to or identical to the one shown in figure 22B with the components 337, 339, 343, 331a, 333a and 335a can be applied on an instrument as shown in figure 20B, where such an arrangement is configured to control rotation of control tube portion 302a(2,4) by an extra longitudinal slider like longitudinal slider 331a.

[0142] One can even further reduce the number of required steering actuators. For example if one wishes to apply a hand held handle with only one steering input to fully control the direction and magnitude of tip steering and if one wishes to accomplish that with only movement of one finger instead of a less controllable and accurate arm and wrist movement, one can envision the following.

[0143] Figure 23 schematically shows a steering unit that comprises one steering input mechanism that can control two sets of steering wires for steering an instrument tip in any direction.

[0144] To that end, the setup of figure 23 comprises all features of figure 21. In addition, the setup includes steering wires 16(2), 16(4) and a sliding member 302(2,4) configured to control longitudinal movement of steering wires 16(2), 16(4). It is assumed that steering wire 16(2) is located at a 180 degrees tangentially rotated location relative to steering wire 16(4). The four steering wires 16(1), 16(2), 16(3), 16(4) are located at equidistant locations. Sliding member 302(2,4) contains a slit-shaped opening 303(2) for steering wire 16(2) and a slit-shaped opening 303(4) for steering wire 16(4). A pin 305(2), 305(4), respectively, is attached to steering wire 16(2), 16(4), respectively, and accommodated in slit-shaped opening303(2), 303(4), respectively. Slit-shaped opening 303(2), 302(4), respectively, is arranged at an angle r|, cp, respectively, relative to the longitudinal direction. In most practical cases r| = cp. When one now moves sliding member 302(2,4) up / down, as indicated with arrow F7, steering wires 16(2), 16(4) will move in opposite longitudinal directions, as indicated with arrows F4, F5. If r| = cp, steering wires 16(2), 16(4) will move along the same length be it in opposite directions such that one of them is generating a pulling force and the other one is developing a pushing force, thus causing the tip to deflect. The two steering wires 16(2), 16(4) are actuated simultaneously.

[0145] The setup of figure 23 also includes a sliding member 349 provided with a longitudinal slot 351 accommodating a pin 353 which is attached to sliding member 302(2,4). Sliding member 349 can move in longitudinal direction F9 without moving sliding member 302(2,4) in the longitudinal direction. However, when sliding member 349 moves in a direction F8 perpendicular to longitudinal direction F9 sliding member 302(2,4) will be forced by pin 353 inside slot 351 to move in direction F7.

[0146] Moreover, longitudinal sliding member 331 is provided with a slot 355 extending in direction F8 and accommodating a pin 357 which is attached to sliding member 349. Therefore, if sliding member 349 is moved in longitudinal direction F9, longitudinal sliding member 331 is moved in its longitudinal direction F7 too.

[0147] Thus, sliding member 349 can be moved in all directions in a plane of figure 23 and will, thereby, control longitudinal movement of all four steering wires 16(i). The amount of up / down movement F9 will determine the amount of opposite longitudinal movements of steering wires 16(2), 16(4) and the amount of longitudinal back / forth movement F8 will determine the amount of opposite longitudinal movements of steering wires 16(1), 16(3). So, both the amount of deflection and the direction of deflection in 3D space is controlled by a single component, i.e., sliding member 349.

[0148] Figure 24 shows the outside of an embodiment of a steering unit in which the mechanism of figure 23 is implemented with coaxially arranged tubes. All components with a reference number with an affix “a” have the same function as the component with the same reference number without affix “a” in figure 23. Note that the steering mechanism for steering wires 16(1), 16(3) is implementedproximally from the steering mechanism for steering wires 16(2) , 16(4).

[0149] At its proximal end, the instrument is provided with the same functional mechanism as shown in figures 20A, 20B, be it that the two control tube portions 302a(l,3) and 302a(2,4) are implemented in a reversed longitudinal order. On top of control tube portion 302a(l,3), a same longitudinal slider 331a is applied as in figure 22B. The helical slot 335a is now spiraling in the opposite direction but that is technically not important. Longitudinal slider 331a is again configured such that it cannot rotate relative to the underlaying rings 321, 323, e.g., by a mechanism including longitudinal extension 343 inside longitudinal slot 339 inside fourth ring 337 which are not shown in figure 24 but visible in figure 22B. However, like in figures 22A, 22B, longitudinal slider 331a can slide in the longitudinal direction, as indicated with F6, in order to rotate control tube portion 302a(l,3) to operate steering wires 16(1), 16(3) as explained above.

[0150] Moreover, longitudinal slider 33 la is provided with a tangential slot 355a accommodating a pin 357a.

[0151] Proximally from longitudinal slider 331a, the instrument includes a slider 349a. In the tube underlaying, the instrument includes a rotatable operating mechanism for steering wires 16(2), 16(4) as shown on the proximal end of figure 20B. In this embodiment slider 349a is provided with a longitudinal slot 351a accommodating a sliding pin 353a. Sliding pin 353a is attached to rotatable control tube portion 302a(2,4). Longitudinal slider 331a and slider 349a can be made by providing a single tube with a suitable material removal pattern, e.g., by (laser) cutting. However, alternatively they can be made from different tubes.

[0152] A driving element, like tube 359 (which is not shown in figure 24 but shown in figures 25A, 25B) is provided on top of both longitudinal slider 331a and slider 349a. At its distal end, driving tube 359 is attached to slider 349a and at its proximal end driving tube 359 is attached to pin 357a. The result is that if one only rotates the driving tube 359, control tube portion 302a(2,4) is rotated which actuates steering wires 16(2), 16(4) for a first steering plane. Then, longitudinal slider 331a is not actuated because pin 357a can freely move in the tangential direction in tangential slot 355a and does not initiate translation of longitudinal slider 331a in the longitudinal direction. However, when driving tube 359 is only translated in the longitudinal direction, longitudinal slider 331a is also moved in the longitudinaldirection and rotatable control tube portion 302a(l,3) is rotated by pin 333a inside helical slot 335a, as explained with reference to figures 22A, 22B. This actuates steering wires 16(1), 16(3) for a second steering plane. Then, rotatable control tube portion 302a(2,4) is not actuated because sliding pin 353a can freely move in longitudinal slot 351a in the longitudinal direction. When one rotates and translates driving tube 359, both steering planes are actuated. In this way, one control feature (driving element or tube 359) can control two steering planes. This embodiment again only requires the addition of one extra tube with a pre-assembled number of parts and does not significantly increase the required manufacturing effort nor the volume (bulkiness) of the instrument body.

[0153] It is observed that many alternative embodiments are possible. E.g., the function of sliding pin 353a and slider 349a may be reversed. I.e., slider 349a may be attached to rotatable control tube portion 302a(2,4) instead of to driving tube 359 and, then, sliding pin 353a is attached to driving tube 359 and not to rotatable control tube portion 302a(2,4). This is a more compact arrangement because, then, slider 349a is configured for rotation only and does not need space for longitudinal movements.

[0154] Moreover, slider 349a and longitudinal slider 331a can be implemented in reversed longitudinal order such that slider 349a is on the proximal side of longitudinal slider 331a.

[0155] This embodiment is for example very useful in case one wants a simple hand held handle with an accurate means of controlling tip steering in all directions in a way that resembles for example the use of a mouse pad by using one finger only.

[0156] Figures 25 A, 25B show schematic views of a permanently attached handle363. Figure 25 A shows a very schematic cross sectional view of handle 363 and the proximal end of the steerable instrument. It shows driving tube 359 surrounding all other steering tubes (not drawn again in figure 25 A) and which driving tube 359 is attached to slider 349a and pin 357a shown in figure 24. An extra operating tube 358 may be applied which is surrounding and attached to driving tube 359 and may be made of a material, e.g., a suitable plastic with a roughened surface, such that one can easily shift and / or rotate the operating tube 358. Thus, operating tube 358 can be moved in a longitudinal direction and / or a circumferential direction by forexample a thumb, as is shown in figure 25B. In this way, one can deflect the tip of the steerable instrument in any direction and with any magnitude with only one thumb or other finger, as desired. An extra cover 361 may be applied on top of operating tube 358 with an opening 360 through which a user can operate operating tube 358 with a finger.

[0157] Figure 26 shows handle 363 like the one shown in figure 25A but now with a simple coupling mechanism that allows for detaching operating tube 358 and cover 361 from the steerable instrument, to enable multiple uses of the handle and single use of the steerable instrument. As drawn, coupling and detaching can, in an example, be established by for example a locking pin 365 configured to lock operating tube 358 to driving tube 359 and a locking pin 367 configured to lock cover 361 to outer tube 203. Such locking pins can be pulled back to unlock. Once locked locking pin 365 causes operating tube 358 to be only movable together with driving tube 359 in all directions and locking pin 367 causes cover 361 to be locked to outer tube 203 in all directions. Obviously all other well-known detachable locking mechanisms such as bayonet locks, locking balls, levers or other mechanisms can be used, instead of locking pins. It is easy to understand that this configuration has many advantages as compared to currently available solutions. The instrument part is relatively cheap to manufacture and is very compact although it contains all complexity needed for translating one single finger input to full control of the instrument’s tip. Furthermore, the instrument can be made of one single material, which is very advantageous for improving waste management. The re-useable handle contains a minimum of mechanical parts and potentially can easily be cleaned and re-sterilized and also is relatively cheap to manufacture.

[0158] Figure 27 presents a more simplified form of the steering unit shown in figure 23. The same reference numbers refer to the same components as in figure 23. Instead of sliding member 331 and sliding member 349, the setup of figure 27 includes one sliding member 371 which can be moved in opposite longitudinal directions F6a, F6b and opposite directions F8a, F8b which are perpendicular to longitudinal directions F6a, F6b. Sliding member 371 includes slot 335 accommodating pin 333 and a further slot 369 accommodating pin 353. In an embodiment further slot is arranged in a direction at a same, but opposite angle relative to the longitudinal direction. In fact, apart from components 371, 333, 335,353 and 369, the setup of figure 27 is the same as of figure 19.

[0159] As a person skilled in the art will understand, independent control of longitudinal movements of the sets of steering wires 16( 1 ) / l 6(3) and 16(2), 16(4) is also possible with the mechanism of figure 27 by a suitable movement of sliding member 371. For instance, by moving sliding member 371 in a straight direction coinciding with further slot 369 one only operates steering wires 16(1), 16(3), and by moving sliding member 371 in a straight direction coinciding with slot 335 one only operates steering wires 16(2), 16(4). With other movements one controls longitudinal movements of all four steering wires.

[0160] Figures 28 A thru 28D show an embodiment in which the mechanism of figure 27 is implemented by several tubes. Figure 28A shows the tube assembly containing the tubes required for the steering wires 16(i) and the attached pin and guiding slot. Figure 28A is identical to the one shown in figure 20A, be it that rings 321, 323, 327 are not shown in figure 28 A. The same reference numbers refer to the same components. Figure 28B shows the rotating tubes with the slots that control steering element displacement when these tubes are rotated. I.e., Figure 28B is identical to figure 22B and the same reference numbers refer to the same components.

[0161] Figure 28C shows a first tube portion 373 and a second tube portion 375. First tube portion 373 is arranged on top of a portion of rings 321 and 323 as well as on rotatable control tube portion 302a(l,3). Moreover, first tube portion 373 is attached to rotatable control tube portion 302a(l,3) but can freely rotate around rings 321 and 323. Thus, rotating first tube portion 373 causes opposite longitudinal movements of steering wires 16(1), 16(3). Second tube portion 375 is arranged on top of a portion of rings 323 and 327 as well as on rotatable control tube portion 302a(2,4). Moreover, second tube portion 375 is attached to rotatable control tube portion 302a(2,4) but can freely rotate about rings 323 and 327. Thus, rotating second tube portion 375 causes opposite longitudinal movements of steering wires 16(2), 16(4).

[0162] Figure 28D shows a single drive tube 376 provided with a first helical slot 377 and a second helical slot 379. First and second helical slots 377, 379 are spiraling in opposite directions. A pin 381 inside second helical slot 379 is shown, which pin 381 is attached to second tube portion 375. There is also a pin[not visible in figure 28D] inside helical slot 377, which is attached to first tube portion 373. It is observed that first tube portion 373 and second tube portion 375 can be left out. Then, pin 381 is directly attached to rotatable control tube portion 302a(2,4), and the pin inside first helical slot 377 is directly attached to rotatable control tube portion 302a(l,3). Pin 381 can be made from the same tube as drive tube 376, e.g., by (laser) cutting.

[0163] Helical slots 377, 379 force the pins 381 in a rotating direction dependent on the longitudinal and rotational movement of drive tube 376. Each rotational and longitudinal position of drive tube 376 forces the pins 381 in a predetermined discrete position associated with a unique deflected position of the tip in 3D space. Appropriate software and control motors could easily control the movement of drive tube 376 such that the desired tip steering is established. For a hand controlled version, this mechanism is also useable. If one only translates drive tube 376, two steering planes are actuated simultaneously in the same amount. Mentally, if one shifts drive tube 376 forward and back in the longitudinal direction, one would expect that the tip moves down and up in a vertical plane. But because two steering planes are actuated simultaneously, the tip will move in the vertical plane as well as in the horizontal plane with the same magnitude. The tip steering direction therefor has a 45 degree angle deviation from the vertical plane. To solve this, the instrument shaft may be connected with a 45 degrees offset to the handle. This will result in tip steering in planes corresponding to what one would expect. Pushing forward drive tube 376 and pulling it back will now result in a down and up movement in a vertical plane. Rotating drive tube 376 will now result in tip movement in the horizontal plane.

[0164] All above embodiments show mechanisms based on the assumption that either a rotating or a sliding coaxially arranged tube segment is the preferable way to enable a coupling to a robot or a hand held handle that can be established by an end user on site. From the perspective of integral manufacturing an instrument with a minimum of separate parts and a minimum of assembly effort, one could also use the methods as proposed in W02009112060, WO2009127236, WO2017213491, and WO2018067004 for creating other interface types.

[0165] For example, figures 29A, 29B, 29C show a mechanism that can easily bemade integrally and pre-assembled from a tube wall. Figure 29A shows a gear mechanism and figure 29B shows a portion thereof on an enlarged scale. Figure 29A shows a portion of the instrument with intermediate tube 3 provided with steering wires 16(i) of which steering wires 16(1), 16(2) are visible. Outer tube 203 is shown with a first longitudinal slot 413 in which a first serrated slider 403(2) with teeth 406 is located and a second longitudinal slot 415 in which a second serrated slider 403(1) with teeth 408 is located. First serrated slider 403(2) is attached to steering wire 16(2), e.g., by (laser) welding a portion 409 of first serrated slider 403(2) material. Second serrated slider 403(1) is attached to steering wire 16(1), e.g., by (laser) welding a portion 418 of second serrated slider 403(1) material. In between first and second serrated sliders 403(2), 403(1) outer tube 203 has a strip like portion 419 functioning as a spacer between first and second serrated sliders 403(2), 403(1). Strip like portion 419 has a through hole 417 accommodating a gear 401 with teeth 417. Gear 401 has a recess 404 in its centre.

[0166] Figure 29A, 29B shows some fracture elements 407 used during the manufacturing process as explained in detail in, e.g., W02016089202.

[0167] As shown in figure 29C, in this embodiment, the instrument has a cover tube 410 outside outer tube 203. Cover tube 410 has an opening 411 aligned with opening 404 of gear 401.

[0168] In this embodiment steering wires 16(1), 16(2) can be moved in opposite longitudinal directions by rotating gear 401. Rotation of gear 401 can be established by an actuator from which a suitable axle is inserted in recess 404 via opening 411. The advantage of a mechanism like this may be that when compared to embodiments as presented in figures 15 thru 28D this configuration does not require additional layers of tubing to form a complete mechanism that works with a rotational input. Note that, here steering wires 16(). 16(2) are shown adjacent to one another but they can be located at tangentially 180 rotated locations by having a suitable further transmission system between gear 401 and steering wires 16(1), 16(2), e.g. implemented in the same tube from which the steering wires 16(1), 16(2) are made.

[0169] The steering wires 16(1), 16(2) can be substituted for longitudinal control elements configured to perform a function of the instrument, like locking / unlocking bent instrument parts, operating one or more tools at the distal end, etc.

[0170] Another way of using the mechanism of figures 29A-29C provides for even more advantages. The embodiments as described in figures 15 thru 28D, describe mechanisms that can be used to actuate only two opposite moving steering wires that can steer the instrument tip in one plane. By actuation of two planes, independent from each other, one can steer the instrument tip in any direction, by controlling four steering wires.

[0171] However, the use of only four steering wires limits the obtainable force with which a tip can be steered and therefor limits the amount of force that the tip can apply to surrounding tissue. These obtainable forces are dependent on the strength of the steering wires. One cannot increase the dimensions, and therefore the strength of the steering wires limitless. With increasing dimensions also the stiffness increases. Also with steering wires that are relatively thick, there is a probability that steering wires are plastically deformed instead of only elastically when the tip is curved sharper than purely elastic deformation of the steering wires allow. Plastic deformation potentially shortens fatigue life of the steering wires to unacceptable levels. Therefore, in some occasions, one would like to use more than four steering wires per steerable section for obtaining the composite steering wires strength without compromising bending stiffness and deformation characteristics (fatigue life). A big disadvantage is as follows. For example, if one wishes to use eight steering wires and one wishes to steer the instrument tip in a certain direction, usually four steering wires have to be pulled and four steering wires have to be pushed simultaneously, each over a different amount of displacement. Of course, one can increase the number of mechanisms as shown in figure 15 thru 28D to the number of steering wires that are required, but then also the number of actuators has to increase. Controlling an increased number of actuators is practically not doable by hand control and is also more complex to do with for example software and electric motors.

[0172] The mechanism of figures 29A, 29B, 29C provides for a solution when used in a slightly different way. Figures 30A, 30B show a mechanism in which gear 401 can rotate around an axle 423(1,2) that is inserted in recess 404 of gear 401 and attached to an underlying longitudinal control element 421(1,2) arranged in intermediate layer 3 in which also steering wires 16(i) are located. Axle 423(1,2) can be made from outer tube 203, e.g. by cutting a circular portion in the centre ofgear 401 and attaching the circular portion to longitudinal control element 421(1,2).Gear 401 is arranged in a longitudinal slot 402.

[0173] Longitudinal control element 421(1,2) can slide in a longitudinal way, parallel to the instrument’s axis 229. When one translates longitudinal control element 421(1,2), axle 423(1,2) with gear 401, is also moved in a longitudinal way in longitudinal slot 402 and will pull or push the two engaged steering wires 16(1), 16(2) in the same longitudinal direction. However, like in a car’s differential, steering wires 16(1), 16(2) can displace over a different distance, because gear 401 rotates freely. The potentially different displacements of steering wires 16(1), 16(2) ,e.g., caused by one or more bent parts of the instrument body because the body is inserted in a curved channel, will be such that an equilibrium of push or pull forces is reached. Therefore, one automatically gets the correct displacement of two steering wires whilst the composite steering force is equally divided over the two wires.

[0174] The mechanisms as explained with reference to figures 15 thru 28D, that each control one steering plane with two steering wires 16(i), 16(i+ 1 ) can also be used to control longitudinal movements of several longitudinal control element 421 (i,i+l) that hold several respective gears 401 instead of the steering wires directly. Then, each respective longitudinal control element 421 (i(,i+l) controls longitudinal movement of two steering wires 16(i), 16(i+l) and compensates mutual path length differences between them. In that way, for example, one can use eight steering wires to steer the tip in any direction instead of four steering wires. One can arrange the steering wires such that the composite strength of the eight wires is much higher than that of four wires at the same flexibility and fatigue life. The setup is shown in figure 31.

[0175] Figure 31 shows a same steering arrangement as figure 17. So, it can be implemented with components (laser) cut in several coaxial tubes in a way as shown in figures 18A, 18B. The steering arrangement is shown for steering four longitudinal control elements 421(1,2), 421(3,4), 421(5,6), 421(7,8) in a steerable instrument with eight steering wires 16(1) - 16(8) which are equidistantly arranged about the circumference of the instrument. So, every steering wire 16(i) is located 180 degrees tangentially rotated relative to steering wire 16(i+4). The shown steering arrangement steers longitudinal movements of a first longitudinal controlelement 421(1,2) and a second longitudinal control element 421(5,6). First longitudinal control element 421(1,2) controls longitudinal movements of steering wires 16(1), 16(2) via serrated sliders 403(1), 403(2) and a gear 401(5,6) as explained with reference to figures 30 A, 30B. Second longitudinal control element 421(5,6) controls longitudinal movements of steering wires 16(5), 16(6) via serrated sliders 403(5), 403(6) via a gear 401(5,6) in the same way.

[0176] Figure 31 also shows one single sliding member 302(1,2,5,6) with a slitshaped opening 303(1,2) for longitudinal control element 421(1,2). A pin 305(1,2) is attached to longitudinal control element 421(1,2) and accommodated in slitshaped opening 303(1,2). Slit-shaped opening 303(1,2) is arranged at angle 13 relative to the longitudinal axis. Sliding member 302(1,2,5,6) also has a slit-shaped opening 303(5,6) for longitudinal control element 421(5,6). A pin 305(5,6) is attached to longitudinal control element 421(5,6) and accommodated in slit-shaped opening 303(5,6). Slit-shaped opening 303(5,6) is arranged at an angle a relative to the longitudinal axis. In most practical cases a = 13. When one now moves sliding member 302(1,2,5,6) down, as indicated with arrow Fl, steering wires 16(5,6) will move in the right direction, as indicated with arrow F2, and steering wires 16(1), 16(2) will move in the left direction, as indicated with arrow F3. If a = 13, steering wires 16(1), 16(5) will move along the same length be it in opposite directions such that one of them is generating a pulling force and the other one is developing a pushing force. The same holds for steering wires 16(2), 16(6). The four steering wires 16(1), 16(2), 16(5), 16(6) are actuated simultaneously, and the tip will be deflected. Path length differences between adjacent steering wires 16(1) and 16(2) and between adjacent steering wires 16(5) and 16(6) will be compensated, as explained with reference to figures 30A, 30B. In this way, one can increase steering strength, without adverse effects on flexibility or deformation characteristics of the steering wires.

[0177] It is observed that in the setup of figures 30A, 30B, and 31 the longitudinal control elements 421 (i,i+ 1) are cut from the same intermediate tube as steering wires 16(i), 16(i+ 1 ) and serrated sliders 403 (i), 403 (i+1) are cut in outer tube 203. However, in an alternative arrangement, longitudinal control elements 421 (i,i+ 1) are cut from a tube inside or outside that intermediate tube and the steering wires 16(i), 16(i+ 1 ) are serrated themselves. Then, also gear 401 is located in, andpossibly cut from the intermediate tube. Then, the longitudinal elements on the distal side in figure 31 are steering wires 16(1), 16(2), 16(5), 16(6) and gears 401(1,2), 401(5,6) drive them directly.

[0178] The arrangement of figure 31 can be implemented twice in order to control longitudinal movements of all eight steering wires 16(1) - 16(8). To that effect, all setups of figures 19-28D may be used such that the steering unit drives longitudinal control elements 421 (i,i+l) instead of the steering wires 16(1) - 16(8), and each of the longitudinal control elements 421 (i,i+ 1) controls longitudinal movements of two adjacent steering wires 16(i), 16(i+l). Moreover, the embodiment of figure 31 is not restricted to eight steering wires 16(1) - 16(8), but can be used for 8*S steering wires where S = 1, 2, 3, . . . .

[0179] It is also observed that the setup of figure 30A, 30B, 31 can be used to control longitudinal movement of one or more longitudinal control elements 421 having other functions of the instrument, like locking / unlocking bent portions of the instrument in use, or operating one or more tools at the distal end of the instrument.

[0180] Figures 32A, 32, B, 32C, 32D show another way of using gears to actuate steering wires. Here, the same reference numbers as used in figures 29A, 29B, 29B refer to the same components. In this embodiment, the serrated sliders 403(1), 403(2) are operated by a geared pinion 425. Figure 32D shows gears 427 of geared pinion 425 which are in contact with teeth 406, 408 of serrated sliders 403(1), 403(2).

[0181] In an alternative embodiment, no sliders 403(1), 403(2) are applied but steering wires 16(1), 16(2) are themselves provided with a serrated side like serrated sliders 403(1), 403(2). In such an embodiment, gears 427 of geared pinion 425 directly contacts these serrated sides and drives steering wires 16(1), 16(2).

[0182] Figure 32C shows that cover tube 410 may also be applied on top of outer tube 203 where cover tube 410 is provided with a suitable opening for letting pass geared pinion 425. Note that no cover tube 410 needs to be applied if steering wires 16(1), 16(2) are themselves serrated.

[0183] Figure 33 shows an alternative for figures 22A, 22B. I.e., figure 33 schematically shows how a longitudinal movement can be translated in a rotating movement and vice versa by using gears. Figure 33 shows a longitudinal serrated element 429 and a rotatable serrated element 431 which are both in contact with thesame gear 433. A rotating movement of rotatable serrated element 431 causes a longitudinal movement of longitudinal serrated element 429 and vice versa via gear 433. Longitudinal serrated element 429 can be implemented as a portion of a longitudinal slider like longitudinal extension 343 of longitudinal slider 331a of figure 22A. Rotatable serrated element 431 may be control tube portion 302a(l,3) of figure 22A. The mechanism can also be used as an alternative for figures 16A, 16B. Longitudinal serrated element 429 may be a steering wire 16(i) in which case steering wire 16(i) can be driven by rotation of rotatable serrated element 431.

[0184] In a further embodiment, the setup of figure 33 can be used to drive two opposite steering wires 16(1), 16(3). The setup then includes two gears 433 configured to drive the opposite steering wires 16(1), 16(3), respectively, and which are then driven by rotatable element 431 such that rotating rotatable element 431 results in opposite longitudinal movements of the two opposite steering wires 16(1), 16(3).

[0185] Moreover, the setup with control tube portion 302(2,4) can be substituted for an arrangement as shown in figure 33 in which another serrated rotatable element drives steering wires 16(2) and 16(4) - which are then also serrated - via gears.

[0186] Figure 34 shows that a gear can be used to drive an output element at a different speed or magnitude of displacement as compared to the input element. For example, the arrangement shown in figure 34 includes two serrated longitudinal elements 429, 435. Their serrated sides are both in contact with a gear arrangement 437 having a first gear 439 with a first number of teeth and a second set gear 441 with a second number of teeth. Here, the first number is smaller than the second number but that may be the other way around. First gear 437 contacts the serrated side of serrated longitudinal element 429 and gear 441 contacts the serrated side of serrated longitudinal element 435. Then, longitudinal movement of serrated longitudinal element 429 is slower than of serrated longitudinal element 435 depending on the gear ratio between gears 437, 441. Serrated longitudinal element 429 may be a portion of a sliding tube of an instrument. It is obvious that gear arrangement 437 can also be used in the setup of figure 33 instead of gear 433 in order to establish a desired ratio between rotation of rotatable serrated element 431 and translation of longitudinal serrated element 429.

[0187] Figure 35 shows a schematic setup of an alternative for figures 28A-28D.Figure 35 shows a schematic side view of, in this embodiment, a first rotatable element 443 and a second rotatable element 445 which, in this example have the same radius. A third rotatable element 447 is coaxially arranged with the first and second rotatable elements 443, 445. Rotatable element 445 may be proximal from rotatable element 443. Rotatable element 445 is provided with teeth 446 at its distal side and rotatable element 443 is provided with teeth 444 at its proximal side. A gear 450 is provided in between and contacting both teeth 444 and teeth 446. If gear 450 rotates rotatable elements 443, 445 will rotate in opposite directions.

[0188] Gear 450 extends radially into a longitudinal opening 449 in third rotatable element 447. Longitudinal opening 449 has a serrated longitudinal side 448 with teeth engaging gear 450. Rotatable element 447 cannot only rotate but can also be moved in the longitudinal direction.

[0189] This setup can be applied in the setup of figures 28A-28D, i.e., first rotatable element 443 may be control tube portion 302a(l,3) and second rotatable element 445 may be control tube portion 302a(2,4). Moreover, gear 450 is then located between them and they have opposing serrated sides 444, 446. Third rotatable element 447 then substitutes tubes 373, 375 and 359. If so, one can deflect the deflectable tip section in any direction in 3D space by operating third rotatable element 447, e.g., with a thumb, in its longitudinal and / or tangential direction, as explained with reference to figures 28A-28D.

[0190] Mentally, if one shifts third rotatable element 447 forward and back in the longitudinal direction, one would expect that the tip moves down and up in a vertical plane. But because two steering planes are actuated simultaneously, the tip will move in the vertical plane as well as in the horizontal plane with the same magnitude. The tip steering direction therefor has a 45 degree angle deviation from the vertical plane. To solve this, the instrument shaft may be connected with a 45 degrees offset to the handle. This will result in tip steering in planes corresponding to what one would expect. Pushing forward third rotatable element 447 and pulling it back will now result in an down and up movement in a vertical plane. Rotating third rotatable element 447 will now result in tip movement in the horizontal plane.

[0191] Figures 29 thru 35 present a few examples of how mechanisms with slottedelements with corresponding slider pin can be replaced with gear elements. In fact all slot and pin mechanisms could be replaced by gears and vice versa.

[0192] Obviously, one can apply any number of the mechanisms as presented in all embodiments above to actuate any number of steering wires / longitudinal control elements or sets of steering wires / longitudinal control elements or differential drives. For example, if one would like to control two distal steerable sections, one could apply an appropriate combination of the embodiments above to obtain steering of any desired number of steering wires per steerable section whilst the number of actuator inputs could still be minimized to one actuation element (rotatable and sliding) per steerable section.

[0193] One could also use the embodiments described above for actuation of not only steering wires but also for actuation of for example a longitudinal control element used for opening and closing of a surgical gripper or other tools.

[0194] As discussed already, the above embodiments provide huge advantages over currently employed solutions. Currently employed solutions for controlling steering wires usually comprise many separately manufactured parts that require significant assembly effort. The above described embodiments show pre-assembled and easily manufactured parts that one almost gets for free when one keeps in mind that to create an instrument body one has to (laser) cut the required features for the flexible sections and the steering wires anyways. The addition of cutting the mechanisms for the described embodiments in the same tubes in the same manufacturing run is not more expensive and does not require more metal. Even the addition of one or two short tubes for completing the described mechanisms barely add effort or costs.

[0195] Another huge advantage, which was also already discussed, is that a coupling between the instrument and external controllers like for example a reuseable hand held controller or a robot can easily be established because the difficult part of connecting the instrument’s individual steering wires to the remainder of the needed steering mechanisms is already established in the instrument itself. Also the number of required control elements in the external controllers is already reduced significantly by mechanisms in the instrument itself. Possible couplings, that can be established easily by the end user on site can easily be envisioned.

[0196] For example, when a rotating tube is used as an interface, one can easily cut slots in this tube that engage with a key or splines in the receiving part of the used hand controller or robot. Figures 36A, 36B, 36C show an example of the coupling of a disposable instrument 1 with two rotating tubes that engage in two hollow and keyed or splined axles of two electric actuator motors directly, without the addition of other mechanisms or parts in the robot.

[0197] Figure 36A shows the proximal end of an example of the steerable instrument 1. It shows two control tube portions 302a(l,3), 302(2,4). However, there may one or more of such control tube portions as explained before. There may be extra tube portions on top of these control tube portions 302a(l,3), 302(2,4) to protect the helical slits 303a(i) from collecting dust etc. In the shown embodiment, control tube portion 302a(l,3), 302a(2,4), respectively, is provided with a plate 456, 458, respectively, attached to the outer surface of control tube portion 302a(l,3), 302a(2,4), respectively. Here plates 456, 458 are identical and tangentially aligned.

[0198] Figure 36A shows a first motor 452 and a second motor 454 as well as first electrical wiring 453 and second electrical wiring 455, respectively, for first motor 452 and second motor 454, respectively. These wirings 453, 455 are configured to carry driving currents and suitable control signals to first and second motors 452, 454. Both first and second motors 452, 454 have a hollow driving shaft. Figure 36A shows both electrical motors 452 and 454 in their decoupled state. Figure 36B shows the state where steerable instrument is inserted in the hollow shafts of first and second motors 452, 454. In that state, plate 457 of control tube portion 302a(2,4) is inserted into a slot 460 of the hollow shaft of second motor 454 such that rotation of this hollow driving shaft causes rotation of control tube portion 302a(2,4), cf. figure 36C. Though not shown, first motor 452 has a similar slot inside its hollow driving shaft for accommodating plate 456 such that rotation of the hollow driving shaft of first motor 452 causes rotation of control tube portion 302a(l,3). In this way rotations of control tube portions 302a(l,3), 302a(2,4) can be independently controlled, e.g., by suitable software stored in a processor of a robotic system such as to deflect the tip of the steerable instrument in any desired direction in 3D space.

[0199] In the decoupled state, slot 460 of second motor 454 and similar slot of first motor 452 are tangentially aligned, like plates 457, 456, such that control tubeportion 302a(2,4) can pass the slot of first motor 452. In this way the steerable instrument 1 can be easily coupled and decoupled from first and second motors 452, 454.

[0200] The embodiment of figures 36A, 36B is but one example of how control tube portions 302a(l,3), 302a(2,4) can be coupled to first and second motors 452, 454 in a detachable way, as will be evident to persons skilled in the art.

[0201] Figures 36A, 36B, 36C show that steerable instrument 1 has a tube portion 457 located distally from control tube portions 302a(l,3), 302a(2,4) and forming an outer most tube. Tube portion 457 is provided with a plate 459. In practise, first and second motors 452, 454 will be inside a housing. Such a housing is, in this example, provided with a suitable opening through which control tube portions 302a(l,3), 302a(2,4) with plates 456, 457 can pass towards and away from first and second motors 452, 454. Plate 459 and the opening of the housing are then configured such that they lock in a detachable way to one another such that the steerable instrument 1 is locked in both rotation and translation relative to the housing and control tube portions 302a(l,3), 302a(2,4) are correctly aligned with first and second motors 452, 454. The detachable locking can, e,g„ be made by any suitable mechanism, like a clicking or bayonet mechanism.

[0202] Another method is to provide the rotatable or slidable tubular interface of the instrument with spur gear teeth 470 or worm drive gear teeth 472, cf. figures 37 and 38. Advantage of this method is that when one wants to control for example two or more steerable sections in an instrument, one can minimize the length of the total coupling. When coaxial hollow axes with attached motors are used, and one needs four or more motors for controlling two or more sections, the total length of the coupling may get rather long. Now radial placement, as shown, can significantly reduce the length of the coupling, and therefore the total length of the instrument.

[0203] Figure 26 already shows an example of a coupling between a reusable hand controller and in instrument with one combined sliding and rotating interface. Of course, a comparable method can be used to couple this interface to a robot controller.

[0204] It is obvious that also an instrument with two rotating or sliding interfaces can easily be coupled to a hand held actuator that only contains simple additional mechanisms to enable finger control of these interfaces.

[0205] It is observed that the invention is not limited as to the number of tubes. E.g., the instrument may have more tubes than shown in the present examples. Steering wires 16(i) may have mutually connected or attached separate portions made from the tube material of two or more such tubes, as explained in WO20 17213491. Moreover, the instrument may have other longitudinal control elements made from the tube material and configured to perform another function than explained before, e.g., to lock or unlock a curvature of a portion of the body portion, as explained in WO2023287289.

[0206] Though the invasive instrument is shown with one deflectable tip portion, the invention is not restricted to this. I.e., the invasive instrument may have multiple deflectable tip portions.

[0207] All tubes may, at least in part, be made of at least one of the following set of materials: a biocompatible polymeric material, including polyurethane, polyethylene or polypropylene, stainless steel alloys, cobalt-chromium alloys, shape memory alloys such as Nitinol®, plastic, polymer, composites, or other curable material.

[0208] In an embodiment, components of the tubes, including the one or more steering wires 16(i) and longitudinal control elements, result from a material removal technique applied on a wall of the tubes to make suitable material removal patterns, including at least one of photochemical etching, deep pressing, chipping techniques, laser cutting or water cutting. The material removal means can be a laser beam that melts and evaporates material or a waterjet cutting beam and this beam can have a width of 0.01 to 2.00 mm, more typically for this application, between 0.015 and 0.04 mm.

[0209] The wall thickness of tubes depend on their application. For applications in steerable surgical instruments the wall thickness may be in arange of 0.03-2.0 mm, preferably 0.03-1.0 mm, more preferably 0.05-0.5 mm, and most preferably 0.08-0.4 mm. The diameter of the tubes depend on their application. For applications in steerable surgical instruments the diameter may be in a range of 0.5-20 mm, preferably 0.5-10 mm, more preferably 0.5-6 mm. The radial play between adjacent tubes may be in range of 0.01 - 0.3 mm.

[0210] It is observed that pins 305a(i), 307(i), 333a, 353a, 357a, 381 may have any desired form including but not limited to circular, rectangular, or oval.

[0211] Features of the invention explained with reference to the preceding figures may be summarized as follows.

[0212] A first aspect relates to a steerable instrument with at least one deflectable tip portion (13; 74; 75) at a distal side, the steerable instrument including a first steering wire (16(1); 429) attached to the at least one deflectable tip portion (13; 74, 75), the first steering wire (16(1); 429) being part of at least one tube (3; 102, 103; 121) and being separated from other parts of the at least one tube (3; 102, 103; 121) by a first material removal pattern such that the first steering wire (16(1); 429) extends from a proximal end to a distal end of the steerable instrument, the steerable instrument including a steering unit including a first control tube portion (301a(i); 302a(l,3); 431) coaxially arranged with the at least one tube (3), the first control tube portion (301a(i); 302a(l,3); 431) and the first steering wire (16(1)) being configured such that rotation of the first control tube portion (301a(i); 302a(l,3), 431) causes longitudinal movement of the first steering wire (16(1); 429) in a first longitudinal direction in order to deflect the at least one deflectable tip portion (13; 74; 75) in a first plane.

[0213] The first control tube portion (301a(i)) may be provided with a first helical slot (303a(l)), a first sliding element (305a(l)) attached to the first steering wire (16(1)) being provided in the first helical slot (303a(l)) such that rotation of the first control tube portion (301a(i)) causes the longitudinal movement of the first steering wire (16(1)) in the first longitudinal direction.

[0214] The first control tube portion may be a serrated first control portion (431), the steerable instrument being provided with a gear (433) which is configured to translate rotation of the first control tube portion (431) into the longitudinal movement of the first steering wire (429).

[0215] In a first example, the steerable instrument may include a second steering wire (16(3); 435) attached to the at least one deflectable tip portion (13; 74, 75), the second steering wire (16(3); 435) also being part of the at least one tube (3) and being separated from other parts of the at least one tube (3; 102, 103; 121) by a second material removal pattern such that the second steering wire (16(3); 435) extends from the proximal end to the distal end, the first control tube portion (302a(l,3); 431) and second steering wire (16(3); 435) being configured such that rotation of the first control tube portion (302a(l,3)) causes longitudinal movement of the second steering wire (16(3)) in a second longitudinal direction in order to deflect the at least one deflectable tip portion (13; 74; 75)) in the first plane, the second longitudinal direction being opposite to the first longitudinal direction, the second steering wire (16(3); 435) being optionally located at a location 180 degrees tangentially rotated relative to the first steering wire (16(1)).

[0216] In the first example, the first control tube portion (302a(l,3)) may be provided with a second helical slot (303a(3)), a second sliding element (305a(3)) attached to the second steering wire (16(3)) being provided in the second helical slot (303a(3)) such that rotation of the first control tube portion (302a(l,3)) causes the longitudinal movement of the second steering wire (16(3)) in the second longitudinal direction.

[0217] In the first example, the first control tube portion may be a serrated first control tube portion (431), the steerable instrument being provided with gears (433) which are configured to translate rotation of the serrated first control tube portion (431) into the opposite longitudinal movements of the first and second steering wires.

[0218] In the first example, the steerable instrument may include third and fourth steering wires (16(2), 16(4)), respectively, each attached to the at least one deflectable tip portion (13; 74, 75), the third and fourth steering wires (16(2), 16(4)) also being part of the at least one tube (3) and being separated from other parts of the at least one tube (3; 102, 103; 121) by third and fourth material removal patterns, respectively, such that the second and fourth steering wires (16(2), 16(4)) extend from the proximal end to the distal end, the steering unit including a second control tube portion (302(2,4)) coaxially arranged withthe at least one tube (3), the second control tube portion (302a(2,4)) and third and fourth steering wires (16(2), 16(4)) being configured such that rotation of the second control tube portion (302(2,4))) causes longitudinal movements of the third and fourth steering wires (16(2), 16(4)) in opposite longitudinal directions in order to deflect the at least one deflectable tip portion (13; 74; 75)) in a second plane perpendicular to the first plane, the first, second, third and fourth steering wires (16(1), 16(2), 16(3), 16(4)) being optionally located at equidistant locations as seen in the tangential direction of the steerable instrument.

[0219] Then the second control tube portion (302(2,4)) may be provided with third and fourth helical slots (303a(2), 303a(4)), a third sliding element (305a(2)) attached to the third steering wire (16(2)) being provided in the third helical slot (303a(2)) and a fourth sliding element (305a(4)) attached to the fourth steering wire (16(4)) being provided in the fourth helical slot (303a(4)) such that rotation of the second control tube portion (302(2,4))) causes the longitudinal movements of the third and fourth steering wires (16(2), 16(4)) in opposite longitudinal directions.

[0220] Alternatively, then the second control tube portion may be a serrated second control tube portion, the steerable instrument being provided with gears which are configured to translate rotation of the serrated second control tube portion into the opposite longitudinal movements of the third and fourth steering wires.

[0221] The steerable instrument may include a further tube (4; 104; 203) coaxially arranged between the at least one tube (3; 101, 102; 121) and the first control tube portion (301a(i)), the further tube being provided with a first longitudinal slot (309(1)), the first sliding element (305a(l)) being attached to the first steering wire (16(1)) through the first longitudinal slot (309(1)).

[0222] Then the first sliding element may include a first sliding pin (305a(l)) and the further tube may include a second sliding pin (307(1)) attached to both the first sliding pin (305a(l)) and to the first steering wire (16(1)).

[0223] In the first example, the steerable instrument may include a further tube (4; 104; 203) coaxially arranged between the at least one tube (3; 101, 102;121) and the first control tube portion (302a(l,3)), the further tube beingprovided with a first longitudinal slot (309(1)) and a second longitudinal slot (309(3)), the first sliding element (305a(l)) being attached to the first steering wire (16(1)) through the first longitudinal slot (309(1)), the second sliding element (305a(3)) being attached to the second steering wire (16(3)) through the second longitudinal slot (309(3)).

[0224] Then the first sliding element may include a first sliding pin (305a(l)), the further tube including a second sliding pin (307(1)) attached to both the first sliding pin (305a(l)) and to the first steering wire (16(1)), the second sliding element including a third sliding pin (305a(3)), the further tube including a fourth sliding pin (307(3)) attached to both the third sliding pin (305a(3)) and to the second steering wire (16(3)).

[0225] The steerable instrument may include a first component (321) attached to the further tube (203) at a distal side of the first control tube portion (301a(i); 302a(l,3)) and a second component (323) attached to the further tube (203) at a proximal side of the first control tube portion (301a(i); 302a(l,3)) such as to block longitudinal movement of the first control tube portion (301a(i); 302a(l,3)).

[0226] The steerable instrument may include a longitudinal slider (331a) provided with a third helical slot (335a), a third sliding element (333a) attached to the first control tube portion (301a(i); 302a(l,3)) being provided in the third helical slot (335a) such that longitudinal movement of the longitudinal slider (331a) causes rotation of the first control tube portion (301a(i); 302a(l,3)).

[0227] The steerable instrument may include a further tube (4; 104; 203) coaxially arranged between the at least one tube (3; 101, 102; 121) and the first and second control tube portions (302a(l,3); 302(2,4)), the further tube being provided with a first longitudinal slot (309(1)), a second longitudinal slot (309(3)), a third longitudinal slot (309(2)) and a fourth longitudinal slot (309(4)), the first sliding element (305a(l)) being attached to the first steering wire (16(1)) through the first longitudinal slot (309(1)), the second sliding element (305a(3)) being attached to the second steering wire (16(3)) through the second longitudinal slot (309(3)), the third sliding element (305a(2)) being attached to the third steering wire (16(2)) through the third longitudinal slot (309(2)), the fourth sliding element (305a(4)) being attached to the secondsteering wire (16(3)) through the fourth longitudinal slot (309(4)).

[0228] The first sliding element may include a first sliding pin (305a(l)), the further tube including a second sliding pin (307(1)) attached to both the first sliding pin (305a(l)) and to the first steering wire (16(1)), the second sliding element including a third sliding pin (305a(3)), the further tube including a fourth sliding pin (307(3)) attached to both the third sliding pin (305a(3)) and to the second steering wire (16(3)), the third sliding element including a fifth sliding pin (305a(2)), the further tube including a six sliding pin (307(2)) attached to both the fifth sliding pin (305a(2)) and to the third steering wire (16(2)), the fourth sliding element including a seventh sliding pin (305a(4)), the further tube including an eighth sliding pin (307(4)) attached to both the seventh sliding pin (305a(4)) and to the fourth steering wire (16(4)).

[0229] The steerable instrument may include a first component (321) attached to the further tube (203) at a distal side of the first control tube portion (302a(l,3)), a second component (323) attached to the further tube (203) at a proximal side of the first control tube portion (302a(l,3)), a third component (323) attached to the further tube (203) at a distal side of the second control tube portion (302a(2,4)), a fourth component (327) attached to the further tube (203) at a proximal side of the second control tube portion (302a(2,4)) such as to block longitudinal movements of the first and second control tube portions (302a(l,3), 302a(2,4)).

[0230] The steerable instrument may include a longitudinal slider (331a) connected to the first control tube portion (302a(l,3)) such that longitudinal movement of the longitudinal slider (331a) causes rotation of the first control tube portion (302a(l,3)), the steerable instrument including a slider (349a) connected to the second control tube portion (302a(2,4)) such that rotation of the slider (349a) causes rotation of the second control tube portion (302a(2,4)), and including a connecting component (359) connecting the longitudinal slider (331a) and the slider (349a) such that when the connecting component (359) moves in the longitudinal direction it causes longitudinal movement of the longitudinal slider (331a) and when connecting component (359) rotates it causes rotational movement of the slider (349a), wherein the connecting component (359) may have a tubeshape.

[0231] The slider (349a) may be provided with a fifth longitudinal slot (351a) accommodating a ninth sliding pin (353a), the longitudinal slider (331a) may be provided with a third helical slot (335a) and a tangential slot (355a) accommodating a tenth sliding pin (357a), a third sliding element (333a) attached to the first control tube portion (301a(i); 302a(l,3)) being provided in the third helical slot (335a), the connecting component (359) being either attached to both the tenth sliding pin (357a) and to the ninth sliding pin (353a) while the slider (349a) is attached to the second control tube portion (302a(2,4)), or attached to both the tenth sliding pin (357a) and to the slider (349a) while the ninth sliding pin (353a) is attached to the second control tube portion (302a(2,4)).

[0232] The steerable instrument may include a driving element (331a; 359;447) connected to the first control tube portion (302a(l,3)) such that longitudinal movement of the driving element (359; 447) causes rotation of the first control tube portion (302a(l,3)) in a first tangential direction, the driving element (359; 447) being connected to the second control tube portion (302a(2,4)) such that longitudinal movement of the drive element (359; 447) causes rotation of the second control tube portion (302a(2,4)) in a second tangential direction opposite to the first tangential direction, the driving element (359; 447) being also connected to the first and second control tube portions (302a(l,3), 302a(2,4)) such that a tangential rotation of the drive element (359; 447) causes tangential rotation of both the first and second control tube portions (302a(l,3), 302a(2,4)) in the same direction.

[0233] The driving element (331a) may comprise a third helical slot (335a), a third sliding element (333a) attached to the first control tube portion (302a(l,3)) being provided in the third helical slot (335a), and may comprise a fourth helical slot (335a), a fourth sliding element (333a) attached to the second control tube portion (302a(2,4)) being provided in the fourth helical slot (335a).

[0234] The driving element may comprise a tube-shaped driving element (447) having a serrated opening accommodating a gear (450) and configured to rotate the gear (450) when tube-shaped driving element (447) moves in the longitudinal direction, the gear (450) being configured to rotate serrated first and second control tube portions (443, 445) in opposite tangential directions when it rotates.

[0235] In a second aspect the invention relates to a steerable instrument with at least one deflectable tip portion (13; 74; 75) at a distal side, the steerable instrument including a first steering wire (16(1); 429) attached to the at least one deflectable tip portion (13; 74, 75), the first steering wire (16(1); 429) being part of at least one tube (3; 102, 103; 121) and being separated from other parts of the at least one tube (3; 102, 103; 121) by a first material removal pattern such that the first steering wire (16(1); 429) extends from a proximal end to a distal end of the steerable instrument, wherein longitudinal movement of the first steering wire (16(1); 429) causes deflection of the at least one deflectable tip portion (13; 74;75)) in a first plane, the steerable instrument including at least one longitudinal control element (421(1,2)) and a steering unit including a first control tube portion (301a(i); 302a(l,3); 431) coaxially arranged with the at least one tube (3), the first control tube portion (301a(i); 302a(l,3); 431) and the at least one longitudinal control element (421(1,2)) being configured such that rotation of the first control tube portion (301a(i); 302a(l,3)) causes longitudinal movement of the at least one longitudinal control element (421(1,2)) such as to control a function of the steerable instrument, such as locking or unlocking a bent portion of the instrument, or operating a tool at the at least one deflectable tip portion.

[0236] In this second aspect a first longitudinal control element (421(1,2)) may be connected to the first control tube portion (302a(l); 302a(l,3)) at its proximal end and may be connected to the first steering wire (16(1)) and to a second steering wire (16(2)) via a gear arrangement (401(1,2); 401(1,2), 403(1), 403(2)) at its distal end, the first longitudinal control element (421(1,2)) and gear arrangement (401(1,2); 401(1,2), 403(1), 403(2)) being configured such that a longitudinal movement of the first longitudinal control element (421(1,2)) results in longitudinal movements of both the first and second steering wires (16(1), 16(2)) in the same longitudinal direction, the gear arrangement being configured to compensate path length differences between the first and second steering wires (16(1), 16(2)).

[0237] The invention relates to an invasive instrument including a steerable instrument of the first or second aspect.

[0238] The invention relates to a control unit and a steerable instrument,wherein the control unit includes a first motor (452) configured to be detachably coupled to the first control tube portion (302a(l,3)).

[0239] The invention relates to a control unit and a steerable instrument, wherein the control unit includes a first motor (452) and a second motor (454), the first motor (452) being configured to be detachably coupled to the first control tube portion (302a(l,3)) and the second motor (454) being configured to be detachably coupled to the second control tube portion (302a(2,4)).

[0240] In an invasive instrument including a manually operable control unit and a steerable instrument, the manually operable control unit may be configured to allow a user to perform manual movements of the connecting component (359) in both longitudinal and tangential directions with a finger.

[0241] In an invasive instrument including a manually operable control unit and a steerable instrument, the manually operable control unit may be configured to allow a user to perform manual movements of the driving element (359) in both longitudinal and tangential directions with a finger.

[0242] The manually operable control unit may be detachably coupled to the steerable instrument.Path length compensation

[0243] The concept of a driving mechanism based on rotatable bushings can also be applied to compensate for undesired path length changes of steering wires in multi-bendable invasive instruments. In many applications it is desired that deflections of multiple deflectable zones in steerable (invasive) instruments can be controlled entirely independently. However, in many implementations deflections of multiple deflectable zones are dependent. This can be explained with reference to figures 7A, 8 and 9. These figures show an example of an instrument with two deflectable zones 152, 154.

[0244] In figure 7 A, both deflectable zones 152, 154 are not actuated, so extending in a straight direction. Figure 8 shows a desired way of bending deflectable zone 154, i.e., deflectable zone 154 can be bent without affecting the deflection of deflectable zone 152. However, if no extra measures are taken, bending deflectable zone 154 as shown in figure 8 will cause deflectable zone152 to deflect as well as shown in figure 9.

[0245] This is caused by the portion of the steering wire for deflectable zone 152 which is located inside the short side of the deflected deflectable zone 154 obtaining a shorter path length in deflectable zone 154 and the portion of the steering wire for deflectable zone 152 which is located inside the long side of the deflected deflectable zone 154 obtaining a longer path length in deflectable zone 154. As a result, deflectable zone 152 automatically deflects in a direction opposite to the bending direction of deflectable zone 154. This applies both to steering wires on which a pulling or a pushing force is applied.

[0246] Figures 39 A, 39B show an example of independent control of two deflectable zones 152, 154 in a schematic way. In this example, both deflectable zones 152, 154 can be deflected in the plane of the figures by means of suitably arranged steering wires (not shown). Figure 39A shows that deflectable zone 154 is deflected without influencing the straight status of deflectable zone 152. Figure 39B shows that deflectable zone 152 is deflected without influencing the deflected status of deflectable zone 154.

[0247] WO2022260518 of the same applicant as the current patent document discloses mechanisms to compensate for path length differences between steering wires caused by bending a flexible body of an invasive instrument through which these steering wires are running. Some of the embodiments of this prior art patent document are implemented by means of rotatable bushings configured to extend or shorten the length of one or more steering wires in dependence on such bendings of the flexible body. One or more sensing wires control rotation of such bushings by a longitudinal movement. Each sensing wire is attached to a location inside the body and moves in the longitudinal direction when the body bends at that location. The inventor of the present patent document has now found that a similar, but simplified mechanism can be used to compensate for undesired path length variations of steering wires for a certain deflectable zone caused by deflection of another deflectable zone. Here no extra sensing wires are applied. Moreover, the compensation mechanism is integrated in the steering mechanism for one or more steering wires.

[0248] The basic principle can be explained with reference to figure 40.

[0249] Figure 40 shows a schematic setup of a length compensation section380 located at a suitable location in the instrument. The example of figure 40 relates to a steerable instrument with two deflectable zones, e.g. zones 152 and 154 of figures 39A, 39B. Figure 40 explains the principle of the invention in a 2D figure. However, it can be easily implemented in a steerable invasive instrument with coaxial tubes and (laser) cut patterns - or patterns made by any other material removing technique - as will be explained hereinafter. In such an implementation, the plane of figure 40 becomes a circular surface of one or more tubes.

[0250] Figure 40 shows steering wires 16(1,1), 16(2,1) which are guided by surrounding structures such that they can only move longitudinally and not in a vertical direction or in a direction perpendicular to the drawing plane. Steering wire 16(1,1) is configured to steer deflectable zone 154 and steering wire 16(2,1) is configured to steer deflectable zone 152. They are located at the same side of the instrument, such that a path length change of one of the steering wires 16(1,1), 16(2,1) inside the instrument as caused by a deflection of one of the deflectable zones 152, 154 is the same as the path length change of the other steering wire 16(1,1), 16(2,1).

[0251] In more detail, figure 40 shows a first wall 382 extending in a transverse direction perpendicular to the longitudinal direction of steering wires 16(1,1), 16(2,1). Steering wire 16(2,1) is shown to have a portion 16(2,1) at the left side and a portion 16e(2,l) at the right side of length compensation section 380. Length compensation section 380 also comprises a second wall 384 extending in parallel to the first wall 382, and a first slider 320 which can slide up and down between walls 382 and 384 in the transverse direction as indicated with a double arrow dV. First slider 320 is provided with an opening 326 accommodating a second slider 316 such that second slider 316 can slide back and forth in opening 326 in a direction parallel to the longitudinal direction as indicated with a double arrow dH.

[0252] Here, steering wire 16(1,1) extends into the space between first and second walls 382 and 384 through a suitable opening in first wall 382. Steering wire 16(1,1) is provided with a protrusion, like a pin 305(1,1) extending in a slot 303(1,1) inside first slider 320. Here, slot 303(1,1) is straight and extending at an angle 0< al <90 degrees to the longitudinal direction. Note that al may,alternatively, be directed in the opposite direction, -90< al <0.

[0253] Left steering wire portion 16(2,1) also extends into the space between first and second walls 382 and 384 through a suitable opening in first wall 382. Left steering wire portion 16(2,1) is provided with a protrusion, like a pin 312(2,1) extending in a slot 308(2,1) inside second slider 316. Here, slot 308(2,1) is straight and extending at an angle 0< a2 < 90 degrees to the transverse direction. Note that a2 may, alternatively be directed in the opposite direction, -90< a2 <0.

[0254] Right steering wire portion 16e(2,l) also extends into the space between first and second walls 382 and 384 through a suitable opening in second wall 384 such that the left and right steering wire portions 16(2,1), 16e(2,l) extend in opposite directions from length compensation section 380. Right steering wire portion 16e(2,l) is provided with a protrusion, like a pin 314(2,1) extending in a slot 310(2,1) inside second slider 316. Here, slot 310(2,1) is straight and extending in the transverse direction perpendicular to the longitudinal direction.

[0255] All protrusions 305(1,1), 312(2,1), 314(2,1) can be implemented as a fixed protrusion e.g. round or shaped in the geometry of the corresponding slot. However, they may have any other suitable cross section.

[0256] Deflectable zone 154 can be deflected by moving slider 320 in the upward or downward direction because that causes steering wire 16(1,1) to move longitudinally.

[0257] For instance, slider 320 is moved in the upward direction which causes steering wire 16(1,1) to be moved to the right hand direction inside length compensation section 380. In that case steering wire 16(1,1) is situated in an inner curve of deflected zone 154, its path length in the instrument at the left side of length compensation section 380 will be shortened and, consequently, its path length inside length compensation section 380 is increased. Due to the angled slot 303(1,1), first slider 320 is moved upwards in the transverse direction over a distance Hl and the horizontal movement of steering wire 16(1,1) equals a distance La. This movement also moves second slider 316, which is connected to first slider 320 in the transverse direction but which can move freely in the longitudinal direction, upwards over a distance H2, whereHl = H2.

[0258] If right steering wire portion 16e(2,l) is held stationary in place, for example by a (manual or robotic) steering input unit attached to right steering wire portion 16e(2,l), second slider 316 will not move in the longitudinal direction when it moves upward in the transverse direction, because slot 310(2,1) in which protrusion 314(2,1) of right steering wire portion 16e(l,2) is located, is extending in the transverse direction. Due to the other angled slot 308(2,1) in second slider 316, the end of left steering wire portion 16(2,1), attached to protrusion 312(2,1) inside angled slot 308(2,1), is displaced in the longitudinal direction over a distance Lr when second slider 316 moves upward in the transverse direction together with first slider 320. If the tilt angle 90-a2 of slot 308(2,1) in second slider 316 is the same as the tilt angle al of slot 303(1,1) in first slider 320, then the displacement Lr of left steering wire portion 16(2,1) is caused to be exactly the same as the displacement La of the steering wire 16(1,1) and the undesired path length change of steering wire 16(2,1) is compensated for.

[0259] When one now wants to steer deflectable zone 152 at the tip (e.g. located at the left hand side of the drawing of figure 40) of the instrument, one can pull or push right steering wire portion 16e(2,l) in the longitudinal direction (e.g., manually or by a robotic device) and this movement then also pulls or pushes second slider 316 in the longitudinal direction. Because left steering wire portion 16(2,1) is also connected to second slider 316, also left steering wire portion 16(2,1) is pulled or pushed in the longitudinal direction with a same longitudinal displacement as right steering wire portion 16(2,1) and steering is accomplished.

[0260] It is observed that angle al may deviate from angle a2 such that displacements La and Lr may be different, as will be explained hereinafter.

[0261] Internal frictions and activation forces in the length compensation section 380 are strongly dependent on the tilt angles al, 90-a2 of the respective slots 303(1,1), 308(2,1). For example, if slot 303(1,1) in first slider 320 is close to the longitudinal direction one can understand that the activation force needed to move slider 320 up with the steering wire 16(1,1), is very low and the friction between protrusion 305(1,1) and slot 303(1,1) is also very low.However, if slot 303(1,1) in first slider 320 is close to the transverse direction, one can understand that one needs a very high activation force to move first slider 320 up (or down) and that also the friction between protrusion 305(1,1) and slot 303(1,1) is very high. At the same time angle a2 should be minimized to allow protrusion 312(2,1) to slide in slot 308(2,1) with minimum friction once first and second sliders 320, 316 move up or down, but to prevent protrusion 312(2,1) to slide easily in slot 308(2,1) when one pulls or pushes right steering wire portion 16(2,1). So one can conclude that one must minimize tilt angles al, and a2 as much as possible to keep frictions and activation forces at an acceptable level. In the above example, if one wants to minimize the tilt angles al, a2 of both slots 303(1,1), 308(2,1) at given displacements La, Lr and Hl, H2, these tilt angles must be around 45 degrees. A suitable design range for both of them would be between 10-45 degrees.

[0262] The mechanism of figure 40 can be further optimized with respect to frictions, activation forces and obtainable length compensation if one can minimize the tilt angle in combination with given length displacements La and Lr (Lr is preferably equal to La to obtain the correct length compensation).

[0263] It is observed that figure 40 shows but one example. In a, not shown, alternative embodiment slot 308(2,1) is not angled relative to the longitudinal direction but extends in the transverse direction. If so, slot 310(2,1) is angled relative to the longitudinal direction but in a direction mirrored relative to the direction of slot 303(1,1) in a plane perpendicular to the longitudinal direction (and to the direction of slot 308(2,1) in figure 41).

[0264] In a further embodiment, both slots 308(2, 1) and 310(2, 1) can angled relative to the longitudinal direction mirrored relative to a plane perpendicular to the longitudinal direction, cf. figure 43 and 45.

[0265] Figure 41 shows an example of a length compensation section 380 with two steering wires 16(1,1), 16(1,2) configured for steering deflection of deflectable zone 154 and two steering wires 16(2,1), 16(2,3) configured for steering deflectable zone 152. The same reference numbers as used in figure 40 refer to the same components in figure 41. The example has an identical structure for the extra steering wires 16(1,2) and 16(2,3) as the structure in the example of figure 40. In the implementation of the example with coaxial tubes,steering wires 16(1,1) and 161,2) are located at opposite sides, i.e. 180 degrees rotated in the tangential direction, of the instrument. Also, in such an implementation of the example, steering wires 16(2,1) and 16(2,3) are located at opposite sides, i.e. 180 degrees rotated in the tangential direction, of the instrument. Moreover, steering wires 16(1,1) and 16(2,1) are located at the same side of the instrument, and steering wires 16(1,2) and 16(2,3) are located at the same side of the instrument. Figure 41 explains the principle of the example in a 2D figure. However, it can be easily implemented with coaxial tubes and (laser) cut patterns as will be explained hereinafter.

[0266] Figure 41 shows steering wires 16(1,1), 16(1,2), 16(2,1), 16(2,3) which are guided by surrounding structures such that they can only move longitudinally and not in a vertical direction or in a direction perpendicular to the drawing plane. Since steering wires 16(1,1) and 16(2,1) are located at the same side of the instrument, a path length change of one of the steering wires 16(1,1), 16(2,1) as caused by a deflection of one of the deflectable zones 152, 154 inside the instrument is the same as the path length change of the other steering wire 16(1,1), 16(2,1). Since steering wires 16(1,2) and 16(2,3) are located at the same side of the instrument, a path length change of one of the steering wires 16(1,2), 16(2,3) as caused by a deflection of one of the deflectable zones 152, 154 inside the instrument is the same as the path length change of the other steering wire 16(1,2), 16(2,3).

[0267] In more detail, figure 41 shows walls 382, 384, 386 extending in a transverse direction perpendicular to the longitudinal direction of steering wires 16(1,1), 16(1,2), 16(2,1), and 16(2,3).

[0268] Steering wire 16(2,1) is shown to have a portion 16(2,1) at the left side and a portion 16e(2,l) at the right side extending through wall 384. Steering wire 16(2,3) is shown to have a portion 16(2,3) at the left side and a portion 16e(2,3) at the right side extending through wall 384. First slider 320 is provided with a further opening 328 accommodating a third slider 318 such that third slider 318 can slide back and forth in opening 328 in a direction parallel to the longitudinal direction as indicated with a double horizontal arrow.

[0269] Right steering wire portion 16e(2,l) extends through an opening in wall 384 and is provided with a protrusion 305(2,1) extending in a slot 303(2,1)inside a slider 322. Slider 322 is located between walls 384, 386 such that it can only move up and down between them as indicated with a double vertical arrow. Here, slot 303(2,1) is straight and may be oriented at a same angle to the longitudinal direction as slot 303(1,1).

[0270] Here, steering wire 16(1,2) extends into the space between walls 382, 384 through a suitable opening in wall 382. Steering wire 16(1,2) is provided with a protrusion, like a pin 305(1,2) extending in a slot 303(1,2) inside first slider 320. Here, slot 303(1,2) is straight and extending at an angle which is the same as angle al of slot 303(1,1) but mirrored in a plane perpendicular to the longitudinal direction.

[0271] Steering wire portion 16(2,3) also extends into the space between first and second walls 382 and 384 through a suitable opening in wall 382. Left steering wire portion 16(2,3) is provided with a protrusion, like a pin 312(2,3) extending in a slot 308(2,3) inside second slider 318. Here, slot 308(2,3) is straight and extending at an angle which is the same as angle a2 of slot 303(2, 1), however mirrored in a plane perpendicular to the longitudinal direction.

[0272] Steering wire portion 16e(2,3) also extends into the space between first and second walls 382 and 384 through a suitable opening in second wall 384. Steering wire portion 16e(2,3) is provided with a protrusion, like a pin 314(2,3) extending in a slot 310(2,3) inside second slider 316. Here, slot 310(2,3) is straight and extends in the transverse direction like slot 303(1,1).

[0273] Right steering wire portion 16e(2,3) extends through an opening in wall 384 and is provided with a protrusion 305(2,3) extending in a slot 303(2,3) inside slider 322. Here, slot 303(2,3) is straight and may be oriented at a same angle to the longitudinal direction as slot 303(1,2).

[0274] How the setup of the structure for steering wires 16(1,1), 16(2,1) compensates for undesired path length changes of steering wire 16(2,1) inside deflectable zone 154 if deflectable zone is deflected by steering wire 16(1,1), has been explained above. Moreover, above it has been explained how most distal deflectable zone 152 can be steered independently from the steering of deflectable zone 154 with this structure.

[0275] A person skilled in the art will understand that the structure of lengthcompensation section 380 of figure 41 as regards steering wires 16(1,2) and 16(2,3) operates the same as for steering wires 16(1,1) and 16(2,1). The operation of the total structure of figure 41 will now be explained.

[0276] If one moves slider 320 upwards and keeps slider 322 stationary, protrusion 305(1,1) will be moved to the right in angled slot 303(1,1) and steering wire 16(1,1) is forced to move to the right to a same extend. Protrusion 305(1,2) will be moved to the left in angled slot 303(1,2) and steering wire 16(1,2) is forced to move to the left to a same extend. Because the angles of slots 303(1,1) and 303(1,2) are equal but mirrored, the longitudinal movements of steering wires 16(1,1) and 16(1,2) is the same but in opposite directions. Steering wire 16(1,1) will pull and steering wire 16(1,2) will push causing deflectable zone 154 to deflect.

[0277] The path length changes of steering wires 16(2, 1) and 16(2,3) inside deflected deflectable zone 154 will be compensated for because steering wire 16(2,1) is moved inside slot 308(2,1) to the right and steering wire 16(2,3) is moved inside slot 308(2,3) to the left.

[0278] If the angles of slots 303(1,1) and 308(2,1) relative to the longitudinal direction are equal, the path length compensation will be complete. However, these angles may be different as shown in the example of figure 41. If different, the compensation will not be complete and deflectable zone 152 will be deflected too to a certain extend. This may be desired in some circumstances, e.g., in dependence on the curvatures of a tortuous path in which the instrument is to be used or the envisaged operation.

[0279] The same holds for the angles of slots 303(1,2) and 308(2,3). However, note that the angles of slots 303(1,2) and 308(2,3) relative to the longitudinal direction should be the same but mirrored relative to a transverse plane because steering wires 16(2,1) and 16(2,3) should be moving to the same extent, be it in opposite directions.

[0280] The setup of figure 41 allows for independent control of deflecting deflectable zone 152 even if deflectable zone 154 has been deflected. E.g. if slider 316 has been moved upwards and deflectable zone 154 has been deflected, and if one then moves slider 322 upwards both protrusions 305(2,1) and 305(2,3) will be moved to the right in their respective slots 303(2,1) and303(2,3). This causes slider 316 to move to the right in opening 326 without any upwards or downwards force on slider 316 because protrusion 314(2,1) is located in slot 310(2,1) which only extends in the transverse direction. Moreover, this causes slider 318 to move to the left in opening 328 without any upwards or downwards force on slider 318 because protrusion 314(2,3) is located in slot 310(2,3) which only extends in the transverse direction as well.

[0281] This is shown in figure 42. In figure 42, slider 320 has been moved upwards to deflect deflectable zone 154 and slider 322 has been moved upwards to deflect deflectable zone 152 - i.e., a state of the instrument as schematically shown in figure 39B.

[0282] Internal frictions and activation forces in the length compensation mechanism are strongly dependent on the tilt angles of the slots 303(1,1), 303(1,2), 303(2,1), 303(2,3), 308(2,1), 308(2,3). In order to optimize friction and activation forces, one can provide slots 310(2,1) and 310(2,3) with an angle deviating from 90 degrees relative to the longitudinal direction as well.

[0283] An example is shown in figure 43 for slot 310(2,1). In figure 43, both slot 310(2,1) and slot 308(2,1) have a tilt angle / ? relative to the longitudinal direction, be it mirrored relative to a plane perpendicular to the longitudinal direction. Slot 303(1,1) is shown to have a tilt angle a relative to the longitudinal direction. In figure 43, a = 2* / ?. The maximum horizontal displacement of steering wire 16(1,1) and of protrusion 305(1,1) inside length compensation section 380 is La. The maximum horizontal displacement of protrusion 312(2,1) and of protrusion 314(2,1), respectively, inside length compensation section 380 is Lrl and Lr2, respectively, where La = Lrl+Lr2. The maximum horizontal displacement of steering wire 16(2,1) inside length compensation section 380 should be the same as of steering wire 16(1,1), i.e., also be La (in case of a desired complete compensation). However, this horizontal displacement of steering wire 16(2,1) inside length compensation section 380 is taken care of by both angled slots 308(2,1) and 310(2,1) and by slider 316. I.e., for instance, if slider 320 moves upwards such that steering wire 16(1,1) moves to the right along a distance of La and steering wire portion 16e(2,l) is not activated (in order not the deflect deflectable zone 152), protrusion 312(2,1) will move to the right along a distance of Lrl andprotrusion 314(2,1) will move to the left along a distance of Lr2 due to slider 316 moving upward together with slider 320.

[0284] In case in figure 43 a = 2* / ? compensation is complete. However, one can provide slots 308(2,1) and 310(2,1), respectively, with different angles / ?1 and / ?2, respectively, such that a may deviate from / ?1 + / ?2. Then path length compensation is not complete and deflectable zone 152 will also bend more or less when one deflects deflectable zone 154 by moving sliders 320 / 316 upwards or downwards, as schematically shown in figures 44 A and 44B. Note that / ?1 may deviate from / ?2 while still a equals / ?1 + / ?2 such that there is complete compensation.

[0285] Figure 45 shows a variant to the length compensation structure of figures 41, 42.

[0286] As to the part relating to length compensation of steering wires 16(2,1), 16(2,3) due to deflection of deflectable zone 154 caused by steering wires 16(1,1), 16(1,2), the structure of figure 45 can be identical to the one of figures 41, 42. However, in the example shown in figure 45, the slots 310(2,1), 310(2,3) have tilted angles as shown in the embodiment of figure 43.

[0287] In addition thereto, figure 45 shows a slider 324 which can be moved upwards and downwards as indicated with a double arrow. Slider 324 comprises a slot 303(2,2) and a slot 303(2,4), respectively, accommodating a protrusion 305(2,2) and 305(2,4), respectively, attached to a steering wire 16(2,2) and 16(2,4), respectively. Slots 303(2,2), 303(2,4) have a tilt angle relative to the longitudinal direction. They are mirrored as to orientation relative to a plane perpendicular to the longitudinal direction. Their tilt angles relative to the longitudinal direction may be the same as of slots 303(1,1) and 303(1,2), respectively.

[0288] Steering wires 16(2,2), 16(2,4) are configured to deflect deflectable zone 152 in a plane perpendicular to the plane in which deflectable zone 152 can be deflected by steering wires 16(2,1), 16(2,3). In an implementation with coaxial tubes, they extend at instrument sides 90 degrees rotated in the tangential direction relative to steering wires 16(1,1), 16(1,2), 16(2,1), 16(2,3). They are not connected to the length compensation structure inside slider 320 because they are located at sides of the instrument which will not bend in thesame plane as the plane of deflection of deflectable zone 154. I.e., they will not be affected as to path length variations when steering wires 16(1,1) and 16(1,2) are operated to deflect deflectable zone 154.

[0289] When moving slider 324 upwards or downwards, steering wires 16(2,2) and 16(2,4) will be moved in opposite longitudinal directions to deflect deflectable zone 154 in a plane perpendicular to the deflection plane controlled by steering wires 16(2,1), 16(2,3). Thus, deflectable zone 154 can be omnidirectionally deflected.

[0290] Another approach to cope with path length changes may be to avoid it. In a simple configuration this may be done as explained with reference to figures 46 A, 46B which show the basic principle thereof. These figures show deflectable zones 152 and 154. Deflectable zone 154 can be deflected in a single plane by two oppositely arranged steering wires 16(1,1), 16(1,2) which are separated from one another by suitably designed spacers. Deflectable zone 152 can be deflected by four steering wires 16(2,1), 16(2,2), 16(2,3), and 16(2,4). In deflectable zone 152 steering wires 16(2,1) and 16(2,3) are oppositely arranged, i.e., located at 180 degrees rotated locations as seen in the tangential direction. In deflectable zone 152 also steering wires 16(2,2) and 16(2,4) are oppositely arranged, i.e., located at 180 degrees rotated locations as seen in the tangential direction. Between adjacent steering wires 16(2,1), 16(2,2), 16(2,3) and 16(2,4) there is an angular space extending about a tangential angle of 90 degrees. These angular spaces accommodate suitably designed spacers.

[0291] However, within deflectable zone 154, steering wires 16(2,1) and 16(2,2) are arranged as close as possible to one another at a tangential angle as close as possible to 90 degrees from steering wires 16(1,1) and 16(1,2). In the shown embodiment, they extend in the longitudinal direction in deflectable zone 154, separated by a slot resulting from a material removal technique like laser cutting. Here, this slot is located 90 degrees rotated from steering wires 16(1,1) and 16(1,2) in the tangential direction.

[0292] Moreover, within deflectable zone 154, steering wires 16(2,3) and 16(2,4) are arranged as close as possible to one another at a tangential angle as close as possible to 90 degrees from steering wires 16(1,1) and 16(1,2), andopposite to steering wires 16(2,1), 16(2,2). In the embodiment of figures 46A, 46B, they extend in the longitudinal direction in deflectable zone 154, separated by a slot resulting from a material removal technique like laser cutting. Here, this slot is located 90 degrees rotated from steering wires 16(1,1) and 16(1,2) in the tangential direction, and opposite to the slot separating steering wires 16(2,1), 16(2,2).

[0293] If now, steering wires 16(1,1) and 16(1,2) are operated to deflect deflectable zone 154, as shown in figure 46B, all steering wires 16(2,1), 16(2,2), 16(2,3) and 16(2,4) are also forced to deflect in planes parallel to the plane in which steering wires 16(1,1) and 16(1,2) are deflected. However, for them that plane is a neutral plane in the sense that, then, they do not move in the longitudinal direction of the instrument. Consequently, they do not suffer from path length changes and no compensation is required. Deflection of deflectable zone 152 is as good as possible decoupled from deflection of deflectable zone 154.

[0294] In the arrangement shown, in deflectable zone 152, steering wires 16(2,1), 16(2,2), 16(2,3) and 16(2,4) are all arranged at an angle of 45 degrees tangentially rotated relative to steering wires 16(1,1) and 16(1,2) inside deflectable zone 154. However, this is not necessary. This angle may be different. Steering wires 16(2,1), 16(2,2), 16(2,3) and 16(2,4) may be located at any desired tangential location inside deflectable zone 152. Between deflectable zones 152, 154 there is a transition area in which steering wires 16(2,1), 16(2,2), 16(2,3) and 16(2,4) change their tangential location.

[0295] It will evident that the same principle can be applied for any other number of steering wires for deflectable zone 152. If there is only one steering wire 16(2,1), or two steering wires 16(2,1), 16(2,2), or three steering wires 16(2,1), 16(2,2), 16(2,3) for deflecting deflectable zone 152, at least one of them may be located exactly at a tangential location 90 degrees rotated relative to steering wire(s) 16(1,1), 16(1,2).

[0296] The embodiment of figures 46A, 46B can be defined as follows when deflectable zones 152, 154 are controlled by one or more steering wires. It relates to a steerable instrument including at least a first deflectable zone 152 and at least a second deflectable zone 154, the second deflectable zone 154being arranged proximally from the first deflectable zone 152, the steerable instrument including a first set of steering wires including at least one first steering wire 16(2,1) arranged to deflect the first deflectable zone 152 and a second set of steering wires including at least one second steering wire 16(1,1) arranged to deflect the second deflectable zone 154 in a first plane, the first set of steering wires extending longitudinally inside the second deflectable zone 154 90 degrees tangentially rotated relative to the second set of steering wires inside the second deflectable zone 154, and the at least one first steering wire 16(2,1) extending in a longitudinal direction inside the first deflectable zone 154 deviating from 90 degrees tangentially rotated relative to the steering 16(1,1) inside the second deflectable zone such that the first deflectable zone can at least be deflected in a second plane different from the first plane.

[0297] When one wishes deflectable zone 152 to be deflectable in an omnidirectional way one has to arrange all steering wires for deflectable zone 152 to be located inside deflectable zone 154 as close as possible to a plane which is perpendicular to a plane in which steering wires 16(1,1), 16(1,2) are located.

[0298] Figures 47A-47E show portions of five tubes 500-508 with (laser) cut patterns such that they, when inserted into one another in the order of 500, 502, 504, 506, 508 and coaxially aligned can implement the path length compensation structure of figure 45. The figures are not necessarily on the same scale. Below it will be explained in detail how different elements of different tubes are attached to one another.

[0299] In an embodiment, these elements shown in these figures, which take care of the steering of the deflectable zones as well as path length compensation at the distal end, are located at the proximal end of the instrument. Deflectable zones 152 and 154 are located on the left, distal end of these figures but not shown. The same reference numbers in these figures as in earlier figures refer to the same components. As one will see, sliders 320, 322 and 324 are implemented by rotatable bushings made from material of one or more of these tubes. All steering wires / wire portions are strips made from material from one or more of these tubes too. Moreover, all other components are made from material of these tubes.

[0300] Implementation of the schematic examples of figures 40-43, 45 can be done in accordance with the same principles shown in figures 47A-47E. Moreover, it will be evident that the schematic examples of figures 40-43, 45 are some embodiments. The invention also relates to embodiments in which there are more than two deflectable zones which can be deflected by suitable steering wires in a 2D plane or in 3D space.

[0301] Figure 47A shows tube 500 which may be arranged around a nonshown inner tube. Tube 500 has a slot pattern cut, e.g. by a laser beam, from tube material 501. Visible in this figure are (portions of) steering wires 16(1,1), 16(1,2), 16(2,1), 16e(2,l), 16(2,2), 16(2,3), 16e(2,3) and 16(2,4). Steering wire portion 16e(2,3) is located at the rear side of tube 500 and 180 degrees rotated relative to steering wire portion 16e(2,l) and not visible. As seen in the tangential direction, steering wire (portion) 16(1,1), 16(2,1), 16e(2,l) and 16(2,2), respectively, extends 180 degrees rotated opposite to steering wire (portion) 16(1,2), 16(2,3), 16e(2,3) and 16(2,4), respectively. All steering wires can only move in the longitudinal direction. Steering wire portion 16e(2,l) and 16e(2,3), respectively, can move in its longitudinal direction independent from steering wire portion 16(2,1) and 16(2,3), respectively.

[0302] Steering wires 16(1,1) and 16(2,1) run in parallel adjacent to one another. Their center lines are located at locations at a certain angle difference as seen in a cross section perpendicular to the longitudinal direction. Moreover, steering wires 16(1,2) and 16(2,3) run in parallel adjacent to one another. Also their center lines are located at locations at a same angle difference as steering wires 16(1,1) and 16(2,1) as seen in a cross section perpendicular to the longitudinal direction. The exact value of the angle depends on the width of the steering wires which depends on the required strength of these steering wires.

[0303] Steering wires 16(2,2) and 16(2,4) are located opposite to one another and at sides of tube 500 substantially 90 degrees rotated relative to the locations of steering wires 16(2,1) and 16(2,3).

[0304] Figure 47B shows tube 502 having a cut pattern such that it comprises sliders 305t(l,l), 312t(2,l), 314t(2, 1), 305t(2,l), 305t(2,2), and 305t(2,4). These sliders 305t(l,l), 312t(2,l), 314t(2,l), 305t(2,l), 305t(2,2), and 305t(2,4) are located in respective slots such that they can move in the longitudinaldirection but not in the tangential direction. These sliders 305t(l, 1), 312t(2, 1), 314t(2, 1), 305t(2,l), 305t(2,2), 305t(2,4), respectively, are parts of an implementation of protrusions 305(1,1), 312(2,1), 314(2,1), 305(2,1), 305(2,2), and 305(2,4), respectively. Slider 305t(l, 1) is aligned with and attached to steering wire 16(1,1). Slider 312t(2, 1) is aligned with and attached to steering wire 16(2,1). Slider 314t(2, 1) is aligned with and attached to steering wire 16e(2,l). Slider 305t(2,l) is aligned with and attached to steering wire 16e(2,l) too proximal from slider 314t(2, 1). Sliders 305t(2,2) and 305t(2,4), respectively, are aligned with and attached to steering wires 16(2,2) and 16(2,4), respectively. Tube 502 comprises similar sliders [305t(l,2) and 305t(2,3)J aligned with and attached to steering wires 16(1,2) and 16(2,3), respectively, but they are not visible.

[0305] Figure 47C shows tube 504 with different portions 334a, 320a, 316, 318, 340a, 322a, 324a, and 336. Tube portions 334a, 340a, and 336 are neither rotatable nor movable in a longitudinal direction relative to one another. Tube portions 320a, 316, 318, 322a, and 324a are rotatable portions relative to tube portions 334a, 340a, and 336. Tube portions 320a, 322a, and 324a, respectively, are parts of the implementation of slider 320 (further parts are 320b, figure 47D, and 320c, figure 47E), slider 322 (further parts are 322b, figure 47D, and 322c, figure 47E) and slider 324 (further parts are 324b, figure 47D, and 324c, figure 47E), respectively. These tube portions 320a, 322a, and 324a cannot move in the longitudinal direction relative to tube portions 334a, 340a, and 336 due to their attachment to portions 320b, 322b, and 324b of tube 506 (cf. further below). Tube portions 316, 318 are the implementations of sliders 316, 318 and cannot only rotate but also move in the longitudinal direction relative to tube portions 334a, 340a, and 336.

[0306] All slots in the sliders 320, 316, 318, 322, 324 of figure 45 are implemented as spiral slots in rotatable bushings. As shown in figure 47C, slot 303(1,1) is a spiral slot in rotatable portion 320a with a pitch in a first direction. Slot 303(1,2) is a spiral slot in rotatable portion 320a with a pitch in a second direction which is opposite to the first direction. Slot 303(1,1) accommodates a slider 305(1,1) which is an implementation of protrusion 305(1,1). Slot 303(1,2) accommodates a slider 305(1,2) which is an implementation ofprotrusion 305(1,2) but not visible in figure 47C. Sliders 305(1,1) and 305(1,2), respectively, are attached to sliders 305t(l, 1) and 305t(l,2), respectively, e.g., by (laser) welding, and thus to steering wires 16(1,1) and 16(1,2), respectively.

[0307] Slot 308(2,1) is a spiral slot in rotatable and longitudinally movable portion 316 with a pitch in the first direction. Spiral slot 308(2,1) accommodates a slider 312(2,1) which is an implementation of protrusion 312(2,1) and is attached to steering wire 16(2,1) via slider 312t(2,l) in tube 502, e.g., via (laser) welding. Slot 310(2,1) is a spiral slot in rotatable portion 316 with a pitch in the second direction. Spiral slot 310(2,1) accommodates a slider 314(2,1) which is an implementation of protrusion 314(2,1) and is attached to steering wire 16e(2,l) via slider 314t(2, 1) in tube 502, e.g., via (laser) welding.

[0308] Slot 308(2,3) is a spiral slot in rotatable and longitudinally movable portion 318 with a pitch in the second direction. Spiral slot 308(2,3) accommodates a slider 312(2,3) which is an implementation of protrusion 312(2,3) and is attached to steering wire 16(2,3) via slider 312t(2,3) in tube 502, e.g., via (laser) welding. Slot 310(2,3) is a spiral slot in rotatable portion 318 with a pitch in the first direction. Spiral slot 310(2,3) accommodates a slider 314(2,3) which is an implementation of protrusion 314(2,3) and is attached to steering wire 16e(2,3) via slider 314t(2,3) in tube 502, e.g., by (laser) welding. It is observed that sliders 312(2,3), 312t(2,3), 314(2,3), 314t(2,3) are not visible in figure 47C.

[0309] Slot 303(2, 1) is a spiral slot in rotatable portion 322a with a pitch in the first direction. Slot 303(2,3) is a spiral slot in rotatable portion 322a with a pitch in the second direction. Slot 303(2,1) accommodates a slider 305(2,1) which is an implementation of protrusion 305(2,1). Slot 303(2,3) accommodates a slider 305(2,3) which is an implementation of protrusion 305(2,3) but not visible in figure 47C. Sliders 305(2,1) and 305(2,3), respectively, are attached to steering wires 16(2,1) and 16(2,3), respectively, via sliders 305t(2,l) and 305t(2,3), respectively, in tube 502 e.g., by (laser) welding.

[0310] Slot 303(2,2) is a spiral slot in rotatable portion 324a with a pitch in the first direction. Slot 303(2,4) is a spiral slot in rotatable portion 324a with a pitch in the second direction. Slot 303(2,2) accommodates a slider 305(2,2) which isan implementation of protrusion 305(2,2). Slot 303(2,4) accommodates a slider 305(2,4) which is an implementation of protrusion 305(2,4). Sliders 305(2,2) and 305(2,4), respectively, are attached to steering wires 16(2,2) and 16(2,4), respectively, via sliders 305t(2,2) and 305t(2,4), respectively, in tube 502 e.g., by (laser) welding.

[0311] Figure 47D shows tube 506. Tube 506 has at least tube portions 334b, 320b, 340b, 322b, and 324b. Tube portions 334b and 340b, respectively, are attached to tube portions 334a and 340a, respectively, in tube 504 (figure 47C).

[0312] Tube portion 320b is part of slider 320 and comprises longitudinal slots 326, 328. Longitudinal slot 326 accommodates slider 330 which is attached to rotatable tube portion 316 in tube 504 such that rotatable tube portion 316 can slide in the longitudinal direction relative to tube portion 320b - like slider 316 relative to slider 320 in e.g. figure 45. Longitudinal slot 328 accommodates a slider 332 which is attached to rotatable tube portion 318 in tube 504 such that rotatable tube portion 318 can slide in the longitudinal direction relative to tube portion 320b - like slider 318 relative to slider 320 in e.g. figure 45. Such attachments may be done by (laser) welding.

[0313] Tube portions 322b and 324b, respectively, are rotatable and attached to rotatable portions 322a and 324a, respectively in tube 504.

[0314] Tube portions 320b, 322b and 324b can only rotate but not move in the longitudinal direction relative to tube portions 334b and 340b, like the sliders 320, 322 and 324 in figure 45 can only move up and down and not move in the longitudinal direction.

[0315] Figure 47E shows tube 508 with portions 334c, 344, 348, 340c, 322c, and 324c. Tube portions 322c and 324c are rotatable but not movable in the longitudinal direction relative to tube portions 334c and 340c. Tube portions 334c, 340c, 322c, and 324c, respectively, are attached to tube portions 334b, 340b, 322b, and 324b in tube 506 (figure 47D), respectively.

[0316] Tube portion 348 is located between tube portions 344 and 340c and is a spring element, e.g., made by providing a tube portion with a spiral form extending in the tangential direction along a path of more than 360 degrees. Of course spring elements with another form can made out of tube 508 between tube portions 344 and 340c, like some tangentially distributed V-shapedbridges.

[0317] Tube portions 334c and 344 and spring element 349 are configured such that, in the rest state, spring element 348 pushes tube portion 344 against tube portion 334c. The surfaces of tube portions 334c and 344 facing one another, contact one another in the rest state such that they cannot rotate relative to one another. These surfaces are, e.g., serrated by a suitable cut pattern 346 to that effect. So, in the rest state tube portion 344 is locked in relation to tube portion 334c. However, tube portion 344 can be moved away from tube portion 334c against the spring action of spring element 348 in the longitudinal direction - indicated with a longitudinal arrow - such that it can rotate relative to tube portion 334c.

[0318] Tube portion 344 has a slot 350 in which a slider 320c can move in the longitudinal direction. Slider 320c is attached to rotatable tube portion 320b in tube 506 (figure 47D), e.g., by laser welding.

[0319] In use, the instrument with the coaxial tubes 500-508 may be operated - either (partly) manually or (partly) by a robotic device - in the following way.

[0320] To start operating the instrument and deflect one or more of the deflectable zone 152, 154, tube portion 344 is moved longitudinally away from tube portion 344c against the spring force of spring element 348. Slider 320c remains at its position relative to tube portion 334c by sliding longitudinally in slot 350. Then, tube portion 344 is able to be rotated and, by doing so, to force slider 320c to rotate too. This causes tube portion 320b in tube 506 to rotate as well because slider 320c is attached to tube portion 320b. Since tube portion 320b is attached to tube portion 320a in tube 504, tube portion 320a rotates as well causing steering wires 16(1,1), 16(1,2) to move in opposite longitudinal directions and to deflect deflectable zone 154. Depending on the rotation direction of tube portions 320a, 320b, 320c the direction of deflection of deflectable zone 154 can be controlled.

[0321] Once deflectable zone 154 is deflected to a desired extent, one can let tube portion 344 go such that it will be pushed against tube portion 334c and locked as to possible rotation. Thus, the amount of deflection of deflectable zone 154 can be locked too.

[0322] When steering wires 16(1, 1), 16(1,2) move and cause this deflection ofdeflectable zone 154, the path lengths of steering wires 16(2,1), 16(2,3) (cf. figure 47A) will change inside deflected zone 154. This will be compensated for to a certain predetermined amount inside the configuration of figures 47A- 47E. This works as follows

[0323] Tube portion 320b rotates together with tube portion 320c. This causes tube portions 316 and 318, which are both attached to tube portion 320b, to rotate. Consequently, sliders 312(2,1) and 314(2,1), respectively, will slide in slots 308(2,1) and 310(2,1), respectively, and move in opposite directions causing steering wire portions 16(2,1) and 16e(2,l) in tube 500 to move in opposite directions. Moreover, sliders 312(2,3) and 314(2,3), respectively, will slide in slots 308(2,3) and 310(2,3), respectively, and move in opposite directions causing steering wire portions 16(2,1) and 16e(2,l) in tube 500 to move in opposite directions. Thus, the path length changes are compensated. Depending on the pitch sizes of slots 308(2,1), 308(2,3), 310(2,1) and 310(2,3) the amount of compensation is either complete or incomplete. In case of complete compensation deflectable zone 152 remains straight. In case of incomplete compensation deflectable zone 152 is also deflected to a certain predetermined amount.

[0324] It will be apparent to a person skilled in the art that the implementation of figures 47A-47E can be simplified if one desires an implementation of the mechanism as schematically shown in any of the figures 40, 41, 42 or 43. Then, one simply leaves out the elements in figures 47A-47E having reference numbers not shown in these figures 40, 41, 42 or 43. Moreover, it will be apparent to a person skilled in the art that one can add mechanisms to the implementation of figures 47A-47E if one desires a path length compensation mechanism completely implemented by suitable (laser) cut patterns in coaxial tubes for more complex steerable instruments, e.g., one having two or more omnidirectionally deflectable zones.

[0325] Implementation of the path length compensation mechanisms of figures 40, 41, 42 or 43 can be made in many different ways. For instance, while figures 47A-47E show steering wires all made by a (laser) cut pattern such that the steering wires are all in a single tube, that is just one option. The steeringwires can be implemented by attaching two or more steering wire portions manufactured in different coaxial tubes to one another as e.g. explained in WO2017213491.

[0326] Attachments between different components of different coaxial tubes can be done by (laser) welding. However, other techniques may be used like lips manufactured in a component in a first tube and bent into an opening in another component in a second tube inside or outside the first tube. Such lips may be formed as explained in WO2023113598A2.

[0327] Rotation of the rotatable portions 320a, 316, 318, 322a, and 324a can be implemented by motors and / or manually operable steering units like in the embodiments described above.

[0328] Figures 48A-48E show an alternative embodiment. Here, the length compensation mechanism of the steering wires of deflectable zone 152 can be coupled to the tube portion that articulates deflectable zone 154. In the example shown in figures 48A-48E there are two deflectable zones. The most distal deflectable zone 152 can be deflected in all directions, whereas the other one 154 can only be deflected in one plane, like in figures 47A-47E. Of course, this is only an example. The mechanism explained with reference to figures 48A- 48E can be applied in any steering mechanism with two or more deflectable zones, which may be deflectable in one or more planes or in all directions. In order to rotate the tube portion of tube 508 for deflectable zone 154, it needs to be longitudinally moved such that tube portions underneath in tubes 504 and 506 engage with the rotating cylinder concerned of deflectable zone 152, as will be explained in detail hereinafter. Consequently, when the deflectable zone 154 is articulated, steering wires of deflectable zone 152 suffering from path length changes are also exposed to the same displacement, and their change of path lengths may be automatically compensated for. In essence, there is no separate compensation mechanism, but when deflectable zone 154 is articulated, deflectable zone 152 is automatically articulated too. Thus when deflectable zone 152 is articulated, deflectable zone 154 may remain stationary as to its orientation. Also here, instead of the same displacement one can design the compensation mechanism such that deflectable zone 152 is automaticallydeflected about another predetermined angle such that there is only a partial compensation.

[0329] In figures 48A-48E, the same reference signs as used in preceding figures refer to, essentially, the same elements. Details are as follows.

[0330] Tube 500 has steering wire portions 16(1,1), 16(1,2), 16(2,1), 16(2,2), 16(2,3), and 16(2,4), as shown figure 48A. However, steering wire portions 16e(2,l) and 16e(2,3) are absent. Tube 500 also has a rotatable tube portion 354 which cannot move longitudinally.

[0331] Tube 502, as shown in figure 48B, has sliders 305t(l , 1), 305t(l,2), 305t(2,l), 305t(2,2), 305t(2,3), and 305t(2,4) which are each slidable in a longitudinal direction in respective slots and attached to steering wires portions 16(1,1), 16(1,2), 16(2,1), 16(2,2), 16(2,3), and 16(2,4) in tube 502, respectively.

[0332] In tube 504, figure 48C, tube portion 320a is split into two tube portions 320al and 320a2 which are separated by a tube portion 352. Tube portion 352 is attached to material of tube 502 such that it cannot move either tangentially or longitudinally. Tube portion 320a2 can both rotate and move longitudinally to a certain extent. Tube portion 320al comprises spiraling slots 303(1,1) and 303(1,2) with respective sliders 305(1,1) and 305(1,2) like in figure 47C. Sliders 305(1,1) and 305(1,2) in figure 48B, respectively, are attached to sliders 305t(l, 1) and 305t(l,2), respectively.

[0333] Tube portions 316 and 318 are absent.

[0334] Tube portion 322a is split into two tube portions 322al and 322a2. Tube portion 322al has an end facing an end of tube portion 320a2. These two ends are configured such that when contacting one another they can only rotate together to the same extent. This can be done by providing them with suitable serrated matching side surfaces, such that they can be coupled and decoupled. Tube portion 322al comprises spiraling slots 303(2,1) and 303(2,3) with respective sliders 305(2,1) and 305(2,3) like in figure 47C. Sliders 305(2,1) and 305(2,3), respectively, are attached to sliders 305t(2,l) and 305t(2,3) in figure 48B, respectively.

[0335] Tube portion 322al is attached to rotatable tube portion 354 of tube 502 such that tube portion 322al can only rotate and not move longitudinally. Tube portion 322a2 is movable in the longitudinal direction and also rotatable. Tubeportion 322al has an end facing an end of tube portion 322a2. These two ends are configured such that when contacting one another they can only rotate together to the same extent. This can be done by providing them with suitable serrated matching side surfaces, such that they can be coupled and decoupled.

[0336] Tube portion 340a is located proximal from tube portion 322a2. It is not movable in the longitudinal direction and not rotatable due to being suitably attached to material of tube 502. Tube portion 324a comprises spiraling slots 303(2,2) and 303(2,4) with respective sliders 305(2,2) and 305(2,4) like in figure 47C. Sliders 305(2,2) and 305(2,4), respectively, are attached to sliders 305t(2,2) and 305t(2,4), respectively. Proximally from tube portion 324a, tube 504 comprises a tube portion 358a which is attached to tube 502 such that it can neither rotate nor move longitudinally. Therefore, tube portion 324a can only rotate.

[0337] In tube 506, figure 48D, tube portion 320b is split into two tube portions 320b 1 and 320b2, and tube portion 322b is split into two tube portions 322b 1 and 322b2. Tube portion 320b 1 is attached to tube portion 320al. Tube portion 320b2 is attached to tube portion 320a2. Tube portion 320b2 is configured such that it can move in the longitudinal direction away from tube portion 320b 1 to a predetermined maximum extent. Side surfaces of tube portions 320b 1 and 320b2 facing one another are configured such that they remain coupled no matter how far they are longitudinally moved away from one another and can only rotate together.

[0338] Tube portion 322b is not attached to tube portion 322al but to tube portion 322a2 in tube 504. Tube portion 340b is split into two portions 340b 1 and 340b2 which are both attached to tube portion 340a, and tube portion 324b is attached to tube portion 324a. Moreover, tube portion 334b and 358b, respectively, is attached to tube portion 334a and 358b, respectively.

[0339] As shown in figure 48E, tube portion 334c in tube 508 is attached to tube portion 334b. Tube portion 320c is now implemented by means of a tube portion 320c2 and two sliders 320cl which can longitudinally slide in suitable respective slots in tube portion 320c2. Tube portion 320c2 is attached to tube portion 320b2 whereas sliders 320cl are attached to tube portion 320b 1. In the shown embodiment, the distal end of tube portion 320c2 has a serrated surfacewhich matches a serrated surface of the proximal end of tube portion 334c such that when they engage tube portion 320c2 cannot rotate because tube portion 334c cannot rotate and prevents tube portion 320c2 from doing so. However, in an embodiment, such serrated surfaces are absent and tube portion 320c2 can rotate freely.

[0340] Tube portion 322c is now implemented by means of a tube portion 322c2 and a slider 322cl which can longitudinally slide in a suitable slot in tube portion 322c2. Slider 322cl is attached to tube portion 322al. Tube portion 322c2 is, optionally, attached to tube portion 356 in tube 506. Tube portions 340c, 324c and 358c, respectively, are attached to tube portions 340b, 324b and 358b, respectively, in tube 506.

[0341] It is observed that the number of sliders 320cl, 320c2, 322cl may vary.

[0342] For the sake of clarity, all attachments between the tubes 500-502 are separately shown in figures 49A-49E. To simplify the overview, the functioning of tube portions 320al, 320a2, 320b 1, 320b2, 320cl, 320c2 has been summarized by letters A, Al, A2. The functioning of tube portions 322al, 322a2, 322b, 322cl, 322c2 has been summarized by letter B, Bl, B2. The functioning of tube portions 334a, 334b, 334c, 340a, 340b 1, 340b2, 340c, 358a, 358b, 358c - which all function as the “fixed world” - has been summarized by letters D, DI, D2. Tubes 500, 502, 504, 506 and 508, respectively, have been indicated with letters L2, L3, L4, L5 and L6, respectively.

[0343] The functioning of the instrument shown in figures 48A-48E, and 49A- 49E will be explained with reference to figures 50A-50E, and 51A-51E. They are identical to figures 48A-48E but have added arc-shaped and straight arrows to explain coupled rotations and longitudinal movements. Moreover, only the relevant attachments between the tube have been shown.

[0344] First, reference is made to figures 48A-48E and 50A-50E. If one desires an automatic path length compensation of steering wires 16(2,1) and 16(2,3) necessitated by deflection of deflectable zone 154 as controlled by steering wires 16(1,1) and 16(1,2), first, tube portion 320c2 in tube 508 is longitudinally moved towards tube portion 322c2 against the action of spring element 348, as indicated with arrow Tl. Tube portion 320b2 in tube 506 is longitudinally moved away from tube portion 320b 1, because it is attached to tube portion320c2, but only to an extent that tube portions 320b 1 and 320b2 can still rotate together. This is indicated with arrow T2. Tube portion 320b2 pushes tube 322b in a longitudinal direction to a same extent, as indicated with another arrow T2. Tube portion 320a2 in tube 504, which is attached to tube portion 320b2, longitudinally moves to a same extent, as indicated with an arrow T3, such that it is coupled to tube portion 322al. At the same time, because tube portion 322a2 in tube 504 is attached to tube portion 322bl, tube portion 322a2 also moves longitudinally away from tube portion 322al as indicated with an other arrow T3. By doing so, tube portion 322a2 is decoupled from tube portion 322al.

[0345] If tube portion 320c2 in tube 508 is then controlled to rotate - either manually or robotically - as indicated with arrow Rl, figure 50E, tube portions 320b 1 and 320b2 are both forced to rotate as well, indicated with arrows R2, figure 50D. Then, tube portion 320al, due to being attached to tube portion 320b 1 is forced to rotate too, indicated with an arrow R3, figure 50C. Tube portion 320a2, due to being attached to tube portion 320b2 is forced to rotate too, indicated with an other arrow R3, figure 50C. Finally, tube portion 322al, due to being coupled now to tube portion 320a2 is forced to rotate too, indicated with an other arrow R3 in figure 50C.

[0346] The generated rotation R3 of tube portion 320al causes sliders 305(1,1), 305(1,2) to move longitudinally in predetermined opposite directions such as to deflect deflectable zone 154 via steering wires 16(1,1), 16(1,2). At the same time, the coupled rotation R3 of tube portion 322al causes sliders 305(2,1), 305(2,3) to move longitudinally in predetermined opposite directions such as to deflect deflectable zone 152 via steering wires 16(2,1), 16(2,3). The pitch sizes of slots 303(1,1), 303(1,2), 303(2,1), and 303(2,3) determine the relative angles of deflection of deflectable zones 152, 154. As explained above, path length differences may be completely compensated for or to a certain predetermined extent automatically in this way.

[0347] When tube portion 320c2 is not moved towards tube portion 322c2, in the shown embodiment, tube portion cannot rotate because it is blocked from doing so by being coupled to tube portion 334c. However, if tube portions 320c2 and 334c do not have serrated side surfaces, i.e. are not coupled in therest state, tube portion 320c2 can be rotated in the status as shown in figure 48E, both tube portions 320b 1 and 320b2 (figure 48D), and tube portions 320al and 320a2 (figure 48C) will be forced to rotate as well. This causes opposite longitudinal movement of steering wires 16(1,1), 16(1,2 and, thus, deflection of deflectable zone 154, as explained above. However, now tube portion 320a2 is not coupled to tube portion 322al and, thus, tube portion 322al is not forced to rotate and steering wires 16(2,1) and 16(2,3) will suffer from path length changes and deflectable zone 152 will be deflected by these path length changes.

[0348] One can also deflect deflectable zone 152 independent from deflection of deflectable zone 154, as explained with references to figures 51A-51E. To that effect, tube portion 320c2 remains in the inactivated state, figure 5 IE. Tube portion 322c2 is rotated, either manually or robotically, as indicated with an arc-shaped arrow R4, which also causes slider 322cl to rotate. Because slider 322c 1 is attached to tube portion 322b, tube portion 322b rotates as well, as indicated with an arrow R5. Tube portion 356 in tube 506 is also forced to rotate, arrow R5. That has no further consequences.

[0349] Tube portion 322b is attached to tube portion 322a2, and as a consequence tube portion 322a2 will rotate, as indicated with an arrow R6. In this state, tube portions 322al, 322a2 are coupled, such that tube portion 322al is also forced to rotate, also indicated with an arrow R6. This causes sliders 305(2,1) and 305(2,3) to move in opposite longitudinal directions causing deflectable zone 152 to deflect. Note that, because tube portions 320c 1 and 322c2 in tube 508, figure 5 IE, rotate independently and there are no couplings in other tubes either now, deflectable zone 154 will not be deflected.

[0350] It will be evident to persons skilled in the art that steering wires 16(2,2) and 16(2,4) can be controlled independently by controlling rotation of tube portion 324c in tube 508.General remark

[0351] The examples and embodiments described herein serve to illustrate rather than to limit the invention. The person skilled in the art will be able to designalternative embodiments without departing from the scope of the claims. Reference numbers placed in parentheses in the claims shall not be interpreted to limit the scope of the claims. Items described as separate entities in the claims or the description may be implemented as a single or multiple hardware items combining the features of the items described.

[0352] It is to be understood that the invention is limited by the annexed claims and its technical equivalents only. In this document and in its claims, the verb "to comprise" and its conjugations are used in their non-limiting sense to mean that items following the word are included, without excluding items not specifically mentioned. In addition, reference to an element by the indefinite article "a" or "an" does not exclude the possibility that more than one of the element is present, unless the context clearly requires that there be one and only one of the elements. The indefinite article "a" or "an" thus usually means "at least one".

Claims

CLAIMS1. A steerable instrument with at least one deflectable zone (13; 152; 154) at a distal end, the steerable instrument including a first steering wire (16(1); 16(1,1); 429) attached to the at least one deflectable zone (13; 152; 154), the first steering wire (16(1); 16(1,1); 429) being part of at least one tube (3; 102, 103; 121; 500) and being separated from other parts of the at least one tube (3; 102, 103; 121; 500) by a first material removal pattern such that the first steering wire (16(1); 16(1,1); 429) extends from a proximal end to the distal end of the steerable instrument, the steerable instrument including a steering unit including a first control tube portion (301a(i); 302a(l,3); 431; 320a) coaxially arranged with the at least one tube (3; 500), the first control tube portion (301a(i); 302a(l,3); 431; 320a) and the first steering wire (16(1); 16(1,1)) being configured such that rotation of the first control tube portion (301a(i); 302a(l,3), 431; 320a) causes longitudinal movement of the first steering wire (16(1); 16(1,1); 429) in a first longitudinal direction in order to deflect the at least one deflectable zone (13; 152; 154) in a first plane.

2. The steerable instrument according to claim 1, wherein the first control tube portion (301a(i); 320a) is provided with a first helical slot (303a(l); 303(1,1)), a first sliding element (305a(l); 305(1,1)) attached to the first steering wire (16(1); 16(1,1)) being provided in the first helical slot (303a(l); 303(1,1)) such that rotation of the first control tube portion (301a(i); 320a) causes the longitudinal movement of the first steering wire (16(1); 16(1,1)) in the first longitudinal direction.

3. The steerable instrument according to claim 1, wherein the first control tube portion is a serrated first control portion (431), the steerable instrument being provided with a gear (433) which is configured to translate rotation of the first control tube portion (431) into the longitudinal movement of the first steering wire (429).

4. The steerable instrument according to claim 1, wherein the steerable instrument includes a second steering wire (16(3); 16(1,2); 435) attached to the at least one deflectable zone (13; 152; 154), the second steering wire (16(3); 16(1,2); 435) also being part of the at least one tube (3; 500) and being separated from other parts of the at least one tube (3; 102, 103; 121; 500) by a second material removal pattern such that the second steering wire (16(3); 16(1,2); 435) extends from the proximal end to the distal end, the first control tube portion (302a(l,3); 431; 320a) and second steering wire (16(3); 16(1,2); 435) being configured such that rotation of the first control tube portion (302a(l,3); 320a) causes longitudinal movement of the second steering wire (16(3); 16(1,2)) in a second longitudinal direction in order to deflect the at least one deflectable zone (13; 152; 154)) in the first plane, the second longitudinal direction being opposite to the first longitudinal direction, the second steering wire (16(3); 16(1,2); 435) being optionally located at a location 180 degrees tangentially rotated relative to the first steering wire (16(1); 16(1,1)).

5. The steerable instrument according to claim 4, wherein the first control tube portion (302a(l,3); 320a) is provided with a second helical slot (303a(3); 303(1,2)), a second sliding element (305a(3); 305(1,2)) attached to the second steering wire (16(3); 16(1,2)) being provided in the second helical slot (303a(3); 303(1,2)) such that rotation of the first control tube portion (302a(l,3); 320a) causes the longitudinal movement of the second steering wire (16(3); 16(1,2)) in the second longitudinal direction.

6. The steerable instrument according to claim 4, wherein the first control tube portion is a serrated first control tube portion (431), the steerable instrument being provided with gears (433) which are configured to translate rotation of the serrated first control tube portion (431) into the opposite longitudinal movements of the first and second steering wires.

7. The steerable instrument according to any of the claim 4-6, wherein the steerable instrument includes third and fourth steering wires (16(2), 16(4)),respectively, each attached to the at least one deflectable zone (13; 154), the third and fourth steering wires (16(2), 16(4)) also being part of the at least one tube (3) and being separated from other parts of the at least one tube (3; 102, 103; 121) by third and fourth material removal patterns, respectively, such that the third and fourth steering wires (16(2), 16(4)) extend from the proximal end to the distal end, the steering unit including a second control tube portion (302(2,4)) coaxially arranged with the at least one tube (3), the second control tube portion (302a(2,4)) and third and fourth steering wires (16(2), 16(4)) being configured such that rotation of the second control tube portion (302(2,4)) causes longitudinal movements of the third and fourth steering wires (16(2), 16(4)) in opposite longitudinal directions in order to deflect the at least one deflectable zone (13; 152; 154)) in a second plane which is angled relative to the first plane, the first, second, third and fourth steering wires (16(1), 16(2), 16(3), 16(4)) being optionally located at equidistant locations as seen in the tangential direction of the steerable instrument.

8. The steerable instrument according to claim 7, wherein the second control tube portion (302(2,4)) is provided with third and fourth helical slots (303a(2), 303a(4)), a third sliding element (305a(2)) attached to the third steering wire (16(2)) being provided in the third helical slot (303a(2)) and a fourth sliding element (305a(4)) attached to the fourth steering wire (16(4)) being provided in the fourth helical slot (303a(4)) such that rotation of the second control tube portion (302(2,4)) causes the longitudinal movements of the third and fourth steering wires (16(2), 16(4)) in opposite longitudinal directions.

9. The steerable instrument according to claim 7, wherein the second control tube portion is a serrated second control tube portion, the steerable instrument being provided with gears which are configured to translate rotation of the serrated second control tube portion into the opposite longitudinal movements of the third and fourth steering wires.

10. The steerable instrument according to claim 2, wherein the steerable instrument includes a further tube (4; 104; 203; 502) coaxially arranged between the at least one tube (3; 101, 102; 121; 500) and the first control tube portion (301a(i); 320a), the further tube being provided with a first longitudinal slot (309(1)), the first sliding element (305a(l); 305(1,1)) being attached to the first steering wire (16(1); 16(1,1)) through the first longitudinal slot (309(1)).

11. The steerable instrument according to claim 10, wherein the first sliding element includes a first sliding pin (305a(l); 305(1,1)) and the further tube includes a second sliding pin (307(1); 305t(l , 1)) attached to both the first sliding pin (305a(l); 305(1,1)) and to the first steering wire (16(1); 16(1,1)).

12. The steerable instrument according to claim 5, wherein the steerable instrument includes a further tube (4; 104; 203; 502) coaxially arranged between the at least one tube (3; 101, 102; 121; 500) and the first control tube portion (302a(l,3); 320a), the further tube being provided with a first longitudinal slot (309(1)) and a second longitudinal slot (309(3)), the first sliding element (305a(l); 305(1,1)) being attached to the first steering wire (16(1); 16(1,1)) through the first longitudinal slot (309(1)), the second sliding element (305a(3); 305(1,2)) being attached to the second steering wire (16(3); 16(1,2)) through the second longitudinal slot (309(3)).

13. The steerable instrument according to claim 12, wherein the first sliding element includes a first sliding pin (305a(l); 305(1,1), the further tube including a second sliding pin (307(1); 305t(l , 1)) attached to both the first sliding pin (305a(l); 305(1,1)) and to the first steering wire (16(1); 16(1,1)), the second sliding element including a third sliding pin (305a(3); 305(1,2)), the further tube including a fourth sliding pin (307(3); 305t(l,2)) attached to both the third sliding pin (305a(3); 305(1,2)) and to the second steering wire (16(3); 16(1,2)).

14. The steerable instrument according to any of the claims 10-13, including afirst component (321) attached to the further tube (203) at a distal side of the first control tube portion (301a(i); 302a(l,3)) and a second component (323) attached to the further tube (203) at a proximal side of the first control tube portion (301a(i); 302a(l,3)) such as to block longitudinal movement of the first control tube portion (301a(i); 302a(l,3)).

15. The steerable instrument according to any of the preceding claims, including a longitudinal slider (331a) provided with a third helical slot (335a), a third sliding element (333a) attached to the first control tube portion (301a(i); 302a(l,3)) being provided in the third helical slot (335a) such that longitudinal movement of the longitudinal slider (331a) causes rotation of the first control tube portion (301a(i); 302a(l,3)).

16. The steerable instrument according to claim 8, wherein the steerable instrument includes a further tube (4; 104; 203) coaxially arranged between the at least one tube (3; 101, 102; 121) and the first and second control tube portions (302a(l,3); 302(2,4)), the further tube being provided with a first longitudinal slot (309(1)), a second longitudinal slot (309(3)), a third longitudinal slot (309(2)) and a fourth longitudinal slot (309(4)), the first sliding element (305a(l)) being attached to the first steering wire (16(1)) through the first longitudinal slot (309(1)), the second sliding element (305a(3)) being attached to the second steering wire (16(3)) through the second longitudinal slot (309(3)), the third sliding element (305a(2)) being attached to the third steering wire (16(2)) through the third longitudinal slot (309(2)), the fourth sliding element (305a(4)) being attached to the second steering wire (16(3)) through the fourth longitudinal slot (309(4)).

17. The steerable instrument according to claim 16, wherein the first sliding element includes a first sliding pin (305a(l)), the further tube including a second sliding pin (307(1)) attached to both the first sliding pin (305a(l)) and to the first steering wire (16(1)), the second sliding element including a third sliding pin (305a(3)), the further tube including a fourth sliding pin (307(3)) attached to both the third sliding pin (305a(3)) and to the secondsteering wire (16(3)), the third sliding element including a fifth sliding pin (305a(2)), the further tube including a six sliding pin (307(2)) attached to both the fifth sliding pin (305a(2)) and to the third steering wire (16(2)), the fourth sliding element including a seventh sliding pin (305a(4)), the further tube including an eighth sliding pin (307(4)) attached to both the seventh sliding pin (305a(4)) and to the fourth steering wire (16(4)).

18. The steerable instrument according to any of the claims 16-17, including a first component (321) attached to the further tube (203) at a distal side of the first control tube portion (302a(l,3)), a second component (323) attached to the further tube (203) at a proximal side of the first control tube portion (302a(l,3)), a third component (323) attached to the further tube (203) at a distal side of the second control tube portion (302a(2,4)), a fourth component (327) attached to the further tube (203) at a proximal side of the second control tube portion (302a(2,4)) such as to block longitudinal movements of the first and second control tube portions (302a(l,3), 302a(2,4)).

19. The steerable instrument according to any of the claims 8 or 16-18, including a longitudinal slider (331a) connected to the first control tube portion (302a(l,3)) such that longitudinal movement of the longitudinal slider (331a) causes rotation of the first control tube portion (302a(l,3)), the steerable instrument including a slider (349a) connected to the second control tube portion (302a(2,4)) such that rotation of the slider (349a) causes rotation of the second control tube portion (302a(2,4)), and including a connecting component (359) connecting the longitudinal slider (331a) and the slider (349a) such that when the connecting component (359) moves in the longitudinal direction it causes longitudinal movement of the longitudinal slider (331a) and when connecting component (359) rotates it causes rotational movement of the slider (349a), wherein the connecting component (359) may have a tube-shape.

20. The steerable instrument according to claim 19, wherein the slider (349a) is provided with a fifth longitudinal slot (351a) accommodating a ninth sliding pin(353a), the longitudinal slider (331a) is provided with a third helical slot (335a) and a tangential slot (355a) accommodating a tenth sliding pin (357a), a third sliding element (333a) attached to the first control tube portion (301a(i); 302a(l,3)) being provided in the third helical slot (335a), the connecting component (359) being either attached to both the tenth sliding pin (357a) and to the ninth sliding pin (353a) while the slider (349a) is attached to the second control tube portion (302a(2,4)), or attached to both the tenth sliding pin (357a) and to the slider (349a) while the ninth sliding pin (353a) is attached to the second control tube portion (302a(2,4)).

21. The steerable instrument according to any of the claims 8, 9 or 16-18, including a driving element (331a; 359; 447) connected to the first control tube portion (302a(l,3)) such that longitudinal movement of the driving element (359; 447) causes rotation of the first control tube portion (302a(l,3)) in a first tangential direction, the driving element (359; 447) being connected to the second control tube portion (302a(2,4)) such that longitudinal movement of the drive element (359; 447) causes rotation of the second control tube portion (302a(2,4)) in a second tangential direction opposite to the first tangential direction, the driving element (359; 447) being also connected to the first and second control tube portions (302a(l,3), 302a(2,4)) such that a tangential rotation of the drive element (359; 447) causes tangential rotation of both the first and second control tube portions (302a(l,3), 302a(2,4)) in the same direction.

22. The steerable instrument according to claim 21 in its dependency on any of the claims 8 or 16-18, wherein the driving element (331a) comprises a third helical slot (335a), a third sliding element (333a) attached to the first control tube portion (302a(l,3)) being provided in the third helical slot (335a), and comprises a fourth helical slot (335a), a fourth sliding element (333a) attached to the second control tube portion (302a(2,4)) being provided in the fourth helical slot (335a).

23. The steerable instrument according to claim 21 in its dependency on claim9, wherein the driving element comprises a tube-shaped driving element (447) having a serrated opening accommodating a gear (450) and configured to rotate the gear (450) when tube-shaped driving element (447) moves in the longitudinal direction, the gear (450) being configured to rotate serrated first and second control tube portions (443, 445) in opposite tangential directions when it rotates.

24. A steerable instrument according to any of the claims 1, 2, 4, 5, 10, 11, 12, 13, comprising at least a first deflectable zone (154) and a second deflectable zone (152), the first deflectable zone (154) being located proximal from the second deflectable zone (152), the first steering wire (16(1,1)) being attached to the first deflectable zone (154), the steerable instrument comprising a fifth steering wire (16(2,1), 16e(2,l)) attached to the second deflectable zone (152), the fifth steering wire (16(2,1), 16e(2,l)) being part of the at least one tube (500) and being separated from other parts of the at least one tube (500) by a fifth material removal pattern such that the fifth steering wire (16(2,1), 16e(2,l)) extends from the proximal end to the distal end of the steerable instrument and is configured for deflecting the second deflectable zone (152), deflection of the first deflectable zone (154) causing a path length change of the fifth steering wire (16(2,1), 16e(2,l)) inside the first deflectable zone (154), the fifth steering wire having a first portion (16(2,1)) extending towards the distal end and a second portion (16e(2,l) located proximally from the first portion (16(2,1)), the first control tube portion (320a) and the first and second portions (16(2,1), 16e(2,l)) of the fifth steering wire being configured such that rotation of the first control tube portion (320a) causes longitudinal movement of at least one of the first and second portions (16(2,1), 16e(2,l)) of the fifth steering wire towards or away from one another such as to compensate for the path length change.

25. The steerable instrument according to claim 24, wherein the steerable instrument includes sixth and seventh steering wires (16(2,2), 16(2,4)), respectively, each attached to the second deflectable zone (152), the sixth and seventh steering wires (16(2,2), 16(2,4)) also being part of the at leastone tube (500) and being separated from other parts of the at least one tube (500) by sixth and seventh material removal patterns, respectively, such that the sixth and seventh steering wires (16(2,2), 16(2,4)) extend from the proximal end to the distal end, the steering unit including a second control tube portion (324a) coaxially arranged with the at least one tube (500), the second control tube portion (324a) and sixth and seventh steering wires (16(2,2), 16(2,4)) being configured such that rotation of the second control tube portion (324a) causes longitudinal movements of the sixth and seventh steering wires (16(2,2), 16(2,4)) in opposite longitudinal directions in order to deflect the second deflectable zone (152) in a second plane which is angled relative to the first plane.

26. The steerable instrument according to claim 25, wherein the second control tube portion (324a) is provided with third and fourth helical slots (303(2,2), 303(2,4)), a third sliding element (305(2,2)) attached to the third steering wire (16(2,2)) being provided in the third helical slot (303(2,2)) and a fourth sliding element (305(2,4)) attached to the fourth steering wire (16(2,4)) being provided in the fourth helical slot (303(2,4)) such that rotation of the second control tube portion (324a) causes the longitudinal movements of the sixth and seventh steering wires (16(2,2), 16(2,4)) in opposite longitudinal directions.

27. The steerable instrument according to any of the claims 24-26, comprising a third control tube portion (316) coaxially arranged with the at least one tube (500) and configured to rotate in the tangential direction together with the first control tube portion (320a) and also being movable in the longitudinal direction, the third control tube portion (316) comprising a fifth slot (308(2,1)) and a sixth slot 310(2,1)), a fifth sliding element (312(2,1)) attached to the first portion (16(2, 1)) of the fifth steering wire being provided in the fifth slot (308(2,1)), a sixth sliding element (314(2,1)) attached to the second portion (16e(2,l)) of the fifth steering wire being provided in the sixth slot (310(2,1)), at least one of the fifth slot (308(2,1)) and sixth slot (310(2,1)) being helical.

28. The steerable instrument according to any of the claims 24-26 in their dependency on any of the claims 4 or 5, comprising an eighth steering wire (16(2,3), 16e(2,3)) attached to the second deflectable zone (152), being part of the at least one tube (500) and being separated from other parts of the at least one tube (500) by an eighth material removal pattern such that the eighth steering wire (16(2,3), 16e(2,3)) extends from the proximal end to the distal end of the steerable instrument and is configured for deflecting the second deflectable zone (152) together with the fifth steering wire (16(2,1)), deflection of the first deflectable zone (154) causing path length changes of the eighth steering wire (16(2,3), 16e(2,3)) inside the first deflectable zone (154), the eighth steering wire having a first portion (16(2,3)) extending towards the distal end and a second portion (16e(2,3) located proximally from the first portion (16(2,3)), the first control tube portion (320a) and the first and second portions (16(2,3), 16e(2,3)) of the eighth steering wire being configured such that rotation of the first control tube portion (320a) causes longitudinal movement of at least one of the first and second portions (16(2,3), 16e(2,3)) of the eighth steering wire towards or away from one another such as to compensate for the path length change.

29. The steerable instrument according to claim 28, comprising a fourth control tube portion (318) coaxially arranged with the at least one tube (500) and configured to rotate in the tangential direction together with the first control tube portion (320a) and also being movable in the longitudinal direction, the fourth control tube portion (318) comprising a seventh slot (308(2,3)) and an eighth slot (310(2,3)), a seventh sliding element (312(2,3)) attached to the first portion (16(2,3)) of the eighth steering wire being provided in the fifth slot (308(2,3)), an eighth sliding element (314(2,3)) attached to the second portion (16e(2,3)) of the eighth steering wire being provided in the eighth slot (310(2,3)), at least one of the seventh slot (308(2,3)) and eighth slot (310(2,3)) being helical.

30. The steerable instrument according to claim 28 or 29, comprising a fifthcontrol tube portion (322a), the fifth control tube portion (322a) and fifth and eighth steering wires (16(2,1), 16(2,3)) being configured such that rotation of the fifth control tube portion (322a) causes longitudinal movements of the fifth and eighth steering wires (16(2,1), 16(2,3)) in opposite longitudinal directions.

31. A steerable instrument according to any of the claims 1, 2, 4, 5, 10, 11, 12, 13, comprising at least a first deflectable zone (154) and a second deflectable zone (152), the first deflectable zone (154) being located proximal from the second deflectable zone (152), the first steering wire (16(1,1)) being attached to the first deflectable zone (154), the steerable instrument comprising a fifth steering wire (16(2,1)) attached to the second deflectable zone (152), the fifth steering wire (16(2,1)) being part of the at least one tube (500) and being separated from other parts of the at least one tube (500) by a fifth material removal pattern such that the fifth steering wire (16(2,1)) extends from the proximal end to the distal end of the steerable instrument and is configured for deflecting the second deflectable zone (152), deflection of the first deflectable zone (154) causing a path length change of the fifth steering wire (16(2,1)) inside the first deflectable zone (154), the steerable instrument comprising a sixth control tube portion (322a) which can be coupled and decoupled from the first control tube portion (320al, 320a2), the sixth control tube portion (322a) and fifth steering wire (16(2,1)) being configured such that rotation of the sixth control tube portion (322a) causes longitudinal movement of the fifth steering wire (16(2,1), the first control tube portion (320al, 320a2) and the sixth control tube portion (322a) being configured to rotate together when they are in the coupled state.

32. A steerable instrument with at least one deflectable zone (13; 152; 154) at a distal side, the steerable instrument including a first steering wire (16(1); 429) attached to the at least one deflectable zone (13; 152; 154), the first steering wire (16(1); 429) being part of at least one tube (3; 102, 103; 121) and being separated from other parts of the at least one tube (3; 102, 103;121) by a first material removal pattern such that the first steering wire (16(1); 429) extends from a proximal end to a distal end of the steerable instrument, wherein longitudinal movement of the first steering wire (16(1); 429) causes deflection of the at least one deflectable zone (13; 152; 154)) in a first plane, the steerable instrument including at least one longitudinal control element (421(1,2)) and a steering unit including a first control tube portion (301a(i); 302a(l,3); 431) coaxially arranged with the at least one tube (3), the first control tube portion (301a(i); 302a(l,3); 431) and the at least one longitudinal control element (421(1,2)) being configured such that rotation of the first control tube portion (301a(i); 302a(l,3)) causes longitudinal movement of the at least one longitudinal control element (421(1,2)) such as to control a function of the steerable instrument, such as locking or unlocking a bent portion of the instrument, or operating a tool located at the distal end.

33. The steerable instrument according to claim 32, wherein a first longitudinal control element (421(1,2)) is connected to the first control tube portion (302a(l); 302a(l,3)) at its proximal end and is connected to the first steering wire (16(1)) and to a second steering wire (16(2)) via a gear arrangement (401(1,2); 401(1,2), 403(1), 403(2)) at its distal end, the first longitudinal control element (421(1,2)) and gear arrangement (401(1,2); 401(1,2), 403(1), 403(2)) being configured such that a longitudinal movement of the first longitudinal control element (421(1,2)) results in longitudinal movements of both the first and second steering wires (16(1), 16(2)) in the same longitudinal direction, the gear arrangement being configured to compensate path length differences between the first and second steering wires (16(1), 16(2)).

34. ,The steerable instrument according any of the preceding claims, wherein the at least one tube (3; 102, 103; 121) includes a ring-shaped end portion (314) at its distal end to which the first steering wire (16(1)) is attached.

35. The steerable instrument according to any of the preceding claims, whereincomponents of the instrument are made of at least one of the following set of materials: a biocompatible polymeric material, including polyurethane, polyethylene or polypropylene, stainless steel alloys, cobalt-chromium alloys, shape memory alloy such as Nitinol®, plastic, polymer, composites, or other curable material.

36. An invasive instrument including a steerable instrument according to any of the preceding claims.

37. An invasive instrument including a control unit and a steerable instrument according to any of the claims 1-36, wherein the control unit includes a first motor (452) configured to be detachably coupled to the first control tube portion (302a(l,3); 320a).

38. An invasive instrument including a control unit and a steerable instrument according to any of the claims 7-9, 16-23, 25, 26 wherein the control unit includes a first motor (452) and a second motor (454), the first motor (452) being configured to be detachably coupled to the first control tube portion (302a(l,3); 320a) and the second motor (454) being configured to be detachably coupled to the second control tube portion (302a(2,4); 324a).

39. An invasive instrument including a manually operable control unit and a steerable instrument according to any of the claims 19 or 20, the manually operable control unit being configured to allow a user to perform manual movements of the connecting component (359) in both longitudinal and tangential directions with a finger.

40. An invasive instrument including a manually operable control unit and a steerable instrument according to any of the claims 21 or 22, the manually operable control unit being configured to allow a user to perform manual movements of the driving element (359) in both longitudinal and tangential directions with a finger.

41. An invasive instrument according to claim 39 or 40, wherein the manually operable control unit is detachably coupled to the steerable instrument.

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