ENDOSCOPE WITH A BENDING SECTION CONTROLLED BY STEERING WIRES

An endoscope (1) having a bending section (20) including segments (22) connected to each other by hinges (24). The bending section has a central passage (12) passing each segment (22) and extends from a distal end to a proximal end, where an inner surface is facing and encircling the central passage (12). At least two grooves (18) into the inner surface extend in parallel with the central passage (12) and in open connection with the central passage. Two steering wires (25) pass in the grooves through the bending section. An anchor (15, 15′, 15″) is provided with a holding part (17, 17′) such that displacement of the steering wires (25) from the grooves (18) towards a center of the central passage (12) is blocked.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from and the benefit of European Patent Application No. 23 199 852.7, filed Sep. 26, 2023; the disclosure of said application is incorporated by reference herein in its entirety.

TECHNICAL FIELD

The present disclosure relates to an endoscope comprising an insertion cord including a bending section. Bending of the bending section is controlled by steering wires running in dedicated parts of the bending section.

BACKGROUND

Flexible endoscopes for medical purposes are often provided with a bending section at a distal end of an insertion tube. The bending section enables the user of the endoscope to maneuver the distal tip of the endoscope inside the human anatomy, such as in the airways, in the kidneys or the gastro-intestinal system, and e.g., to study or perform procedures at tissue of interest. The bending section is typically bent by pulling steering wires. If the endoscope is a 2-way bending endoscope, i.e., bending in two opposite directions but in the same plane, the bending section will typically be controlled by two steering wires, which are controlled by one steering wire actuator arranged in the handle of the endoscope, allowing the user to bend the bending section by adjusting a bending lever. If the endoscope is a four-way bending endoscope, i.e., also bending in two opposite directions in a second plane perpendicular to the first mentioned plane, the bending section will typically be controlled by four steering wires, where one steering wire actuator controls two steering wires for bending in the first plane, and the other steering wire actuator controls the two other steering wires for bending in the second plane. Typically, each steering wire actuator is controlled by a rotational wheel on the endoscope handle.

The steering wires will pass from the handle to the proximal end of the bending section inside wire pipes, which are tubes having limited compressibility. Thereby so-called Bowden cables are formed. The wire pipes are at their proximal end connected inside the handle. At the distal end of the wire pipes, they are connected to the proximal end of the bending section, whereas the steering wires continue through the bending section. The wire pipes are held stationary and translatory movement of the steering wire at the proximal end is transmitted to the distal end as a corresponding translatory movement of the steering wire relative to the wire pipe. The steering wires may translate in closed lumens of the bending section.

For single use endoscopes the bending section may be molded in one piece from a polymer material. Especially for narrow bending sections for endoscopes with a small outer diameter, this molding process can be difficult. E.g., for ureteroscopes, often having a relatively long bending section and an outer diameter of maybe less than 3 mm, it may be difficult to manufacture, and find space for, closed lumens for the steering wires. The long and thin cores needed to mold closed steering wire lumens in the molding process will be fragile and could cause frequent interruptions of the molding process.

It is simpler to manufacture a bending section with grooves or recesses functioning as open channels for the steering wires. Such grooves are in open connection with the rest of the lumen. However, this design of the bending section does involve a minor risk that the steering wire may be displaced from the dedicated open channel during some procedures. For example, a procedure involving specific maneuvering inside the kidney. During such procedure, maneuvering the proximal end of the bending section may be bent in one direction while the operator of the endoscope manipulates the steering wire actuator to bend the distal end of the bending section in the opposite direction.

SUMMARY

It is an object of the present disclosure to prevent displacement of the steering wire out of the open channel or groove. In a first aspect, the object is achieved by a bending section comprising an anchor that prevents such displacement. In a second aspect, the object is achieved by an endoscope comprising said bending section and said anchor. In a third aspect, the object is achieved by a method of making the endoscope according to the second aspect.

In one embodiment according to the first aspect, the bending section comprises an inner, or central, lumen extending in a longitudinal direction. Grooves extend from a periphery of the inner lumen. The anchor comprises a holding part to block displacement of steering wires from the grooves towards the central passage.

One advantage of the anchor is that it enables molding of a small outer diameter bending section, molded in one piece and with the central lumen, while reducing or eliminating the risk of displacement of the steering wires during endoscopic procedures.

The bending section may comprise segments connected to each other by hinges and molded in one piece therewith. The central passage, or inner lumen, passes each segment and extends from a distal end to a proximal end of the bending section, where an inner surface of a circumferential wall of one or more of the segments faces and encircles the central passage. The grooves extend in parallel with, and in open connection with, the central passage. The grooves may be cut-outs in the circumferential walls of the segments.

The hinges allow two neighboring segments to bend relative to each other in a bending plane. The segments and the hinges form an outer surface of the bending section. By neighboring it is meant that the distal surface of a segment faces the proximal surface of its neighbor or adjacent segment (or vise versa) so that the two segments are next to each other in a sequence. By bending plane it is meant a plane that bends with the bending section. Thus, the bending plane traverses the hinges. When the bending section is straight, the bending plane is also straight.

An indent may extend from the outer surface into at least one segment or in at least one hinge. Further, the anchor may be arranged in the indent.

In a variation of the present embodiment, the anchors are placed in at least two indents in positions in segments, or next to segments, placed in only the first 60% of the bending section, i.e., the 60% of the bending section length starting from the proximal end of the bending section and extending toward the distal end of the bending section. Placing the anchors in this first proximal part of the bending section is advantageous, since it has been found that the force on the steering wires in the direction towards a center of the central passage of the bending section is largest in this first proximal part. In general, it is also preferred to keep the total number of anchors low to keep the manufacturing costs as low as possible. Preferably, anchors should be applied in, or in connection with, less than half of the segments. Preferably, anchors should be applied in, or in connection with, less than a third of the segments. In a further variation, anchors are arranged in at least two segments, and in less than 40% of the segments, alternatively in less than 30% of the segments. In one example, anchors are arranged in between 10% and 30% of the segments within the proximal section of the bending section, the proximal section comprising less than 60% of the length of the bending section. The anchors may be spaced so that there is at least one segment without anchors between segments with anchors.

In a variation of the present embodiment, at least two segments are provided with anchors such that displacement of the two steering wires is blocked. Having the anchors within the segments provides a very stable positioning of the anchors.

In a variation of the present embodiment, at least two segments provided with anchors are separated by at least one segment without an anchor. This arrangement, to have the anchors spread out and not in neighboring segments, has been found to provide a good trade-off between manufacturing costs and stability of the bending section with respect to the steering wires not being displaced. In a further variation, there may be at least two segments provided with anchors which are separated by at least two segments without an anchor.

In a variation of the present embodiment, each anchor has a holding part extending into a space where the groove and the central passage meet. The holding part has the advantage that it provides a direct blockage preventing displacement of the steering wire.

In a variation of the present embodiment, the anchors have an exterior surface being level with an outer surface of a segment and the anchors have an interior surface being level with the inner surface. This enables that the anchor may have sufficient dimensions to provide sufficient mechanical strength to resist the forces from the steering wire, e.g., via the coiled spring.

In a variation of the present embodiment, the anchors are made from hardened glue. This enables a simple and cost-effective manufacturing of the endoscope and has also been found to result in a very stable and efficient anchor. In a further variation each anchor is adhered to a segment of the bending section.

In a variation of the present embodiment, a ledge extends from the segment between the indent and the central passage, and the ledge supports the anchor. This provides a strong and stable support for, especially, the glued anchor variation.

In a variation of the present embodiment, the anchors are made from metal discs. This provides anchors which takes up a minimum amount of space in the proximal to distal length direction of the bending section.

In one variation, an anchor arranged in connection with a segment may be able to keep both steering wires inside the grooves.

In another variation, an anchor in a segment may only keep one steering wire in the corresponding groove. Two anchors in the same segment may be preferred, but anchors for the two different steering wires could also be placed in different segments.

Segments of the bending section according to the present embodiment and variations thereof include a proximal end segment, a distal end segment and intermediate segments arranged between the proximal end segment and the distal end segment. The segments are not necessarily identical. Especially, the proximal end segment and the distal end segment may have features enabling the connection of the bending section to an insertion tube of the insertion cord and to a distal tip housing, respectively.

In one embodiment according to the second aspect, the endoscope comprises a bending section according to the first aspect and variations thereof, and steering wires arranged in the grooves of the bending section.

The endoscope may comprise a handle and an insertion cord extending from the handle and including the bending section, and two steering wires extending from the handle to the distal end of the bending section. Each steering wire passes in a respective one of the grooves through the bending section.

In a variation of the present embodiment, the steering wires in the bending section are passing inside coil springs, the coil springs with the steering wires are each arranged in a groove, and the anchor is arranged to block displacement of the coil springs, and thereby the steering wires, from the grooves towards the center of the central passage. This reduces the risk of the steering wires moving into the narrow space between a working channel and the inner surface of the bending section, especially in parts of the bending section where there are no anchors.

In one embodiment according to the third aspect, the method comprises providing a bending section according to the first aspect; arranging two steering wires to extend from the handle to the distal end of the bending section, such that each steering wire passes in a separate groove through the bending section; and arranging an anchor in the indent, where the anchor is provided with a holding part such that displacement of the steering wires from the grooves towards a center of the central passage is blocked.

In another embodiment according to the third aspect, the method comprises: providing a bending section molded in one piece from a fused polymer, and having segments connected to each other by hinges, the hinges allowing two neighboring segments to bend relative to each other in a bending plane, the segments and the hinges forming an outer surface of the bending section, a central passage passing each segment and extending from a distal end to a proximal end of the bending section, where each segment has a circumferential wall, the circumferential wall has an inner surface facing and encircling the central passage, at least two grooves extending from the inner surface into the circumferential wall, the grooves extending in parallel with the central passage and in open connection with the central passage, the central passage and the grooves extending through the segments of the bending section, an indent extending from the outer surface into at least one segment or in at least one hinge; arranging two steering wires to extend from the handle to the distal end of the bending section, such that each steering wire passes in a separate groove through the bending section; arranging an anchor in the indent, where the anchor is provided with a holding part such that displacement of the steering wires from the grooves towards a center of the central passage is blocked.

The embodiments of the method according to the third aspect have been found to be cost-effective ways to manufacture bending sections for endoscopes, e.g., single use endoscopes, having a small diameter insertion cord. The outer diameter of the insertion cord, including the bending section, may be 3 mm or smaller.

In a fourth aspect, the disclosure relates to a system comprising an endoscope according to the second aspect and variations thereof, a monitor and a control unit.

The expression “distal” is defined to be in the direction toward the patient, and “proximal” is defined to be in the direction away from the patient. For the handle of the endoscope, the distal end will be the end where the insertion tube is connected, and the proximal end is the opposite end. Further, the expression “handle” may be a positioning interface, or interface, which functions to control the position of the insertion cord and operating the bending section. The handle, or positioning interface, may be an interface operated by a robotic arm, or it may be a handle operated by the hand of an endoscope user.

One steering wire is counted as one passage from the steering wire actuator (or roller) to the distal end of the bending section. I.e., if the same unbroken steering wire continues from the steering wire actuator to the distal end of the bending section and back to the steering wire actuator, and one part is applied for bending for example to one side and the other part is applied for bending to the opposite side, this is counted as two steering wires, e.g., first and second steering wires.

In the drawings, corresponding reference characters indicate corresponding parts, functions, and features throughout the several views. The drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the disclosed embodiments. For simplicity, this disclosure will focus on a two-way bending endoscope, but the disclosure is relevant for, and covers, also a four-way bending endoscope.

DETAILED DESCRIPTION

FIG.1illustrates an endoscope1, which comprises a handle2, an insertion cord3and an electrical cable with a connector4for connecting the endoscope1to a monitor41. The insertion cord3is the part to be inserted into a body lumen during an endoscopic procedure. The insertion cord comprises a distal tip10, a bending section20and a main tube5. The handle2may comprise an entrance to a working channel6running through the insertion cord to the distal tip. The handle also comprises a bending lever46, which can be used for bending the bending section. The bending section may include a bending cover21.

The distal tip10comprises a camera and light emitters, e.g., in the form of one or more LEDs or the end of an optical light fiber, enclosed in a tip housing. Examples of distal tips10are disclosed in commonly owned U.S. Pat. No. 11,291,352; the disclosure of said patent is incorporated by reference herein in its entirety. The endoscope may consist of an ureteroscope or a cystoscope, comprising a working channel tube in a central passage, the distal tip including the camera, an outer diameter of the bending section being between 2.0 and 3.0 mm, with a cross-sectional area of the working channel tube being at least 40% of a cross-sectional area of the bending section. The shape of the bending section as described below enables such a large working channel tube relative to such a small bending section diameter, which is advantageous for specialized procedures performed with ureteroscopes and cystoscopes and results in some of the problems solved by the anchors.

The monitor41may be combined with an electronic circuit for receiving and processing the image stream from the camera as well as a processor for image processing, user interface, storage of images etc. But the monitor and the electronic circuit and processor may also be separate parts. The electronic circuit and the processor part are also referred to as a control unit42.

FIG.2shows a schematic example of a roller32for a steering wire actuator60configured for bending the bending section by pulling the steering wires25. The steering wires25are moved by rotation of wire drum curved surfaces61, which are a circular arc surfaces or a curved surface placed on the roller32and supporting the steering wires. In the example, one end of the steering wire has been drawn through a fixing structure62and bent back and fastened to itself by a crimp63. The proximal ends of the wire pipes26are fixated in the wire pipe fastener70, whereas the distal ends of the wire pipes are secured to the proximal end of the bending section20. Both the wire pipe fastener70and the roller32are often secured in the handle2. The system inFIG.2is for a two-way bending endoscope.

FIG.3shows a distal end of the insertion cord3of an endoscope, where the bending cover (not shown) typically covering the bending section20and often making this part watertight, has been removed. The proximal end of the bending section is attached to the main tube5, and the distal end of the bending section is attached to the distal tip10. In this example the bending section is molded in one piece and comprises a number of segments22and hinges24. A proximal end segment22′ is connected to the distal end of the main tube5. A distal end segment22″ is connected to the distal tip10. The segments are held together by the hinges24, so that the segments can be bent relative to each other by manipulation of the steering wires25. An example of such a bending section molded in one piece can be seen in commonly owned U.S. Pat. No. 11,937,781; the disclosure of said patent is incorporated by reference herein in its entirety.

Alternatively, the bending section20could be extruded in a relatively soft and resilient material, e.g., a foam-like material, with lumens for steering wires, electrical wires and the tubes passing through.

Steering wires25are connected in a fixed connection to the distal end, e.g., the distal end segment22″. I.e., the steering wire is preferably not movable in relation to the distal end segment. Between the handle and the distal end of the main tube5, or the proximal end of the bending section20, the steering wire25is guided in a wire pipe26which is secured in the handle2distal to the steering wire actuator60. Other designs of the bending section are also possible.

FIGS.4-6show an embodiment of a bending section20according to the first aspect, where the bending section20is provided with only one inner lumen or central passage12. This central passage12has grooves or recesses18(shown inFIG.6) in open connection with the rest of the central passage12. The steering wires25are arranged in these grooves18. An anchor15is provided to avoid that the steering wire25is displaced from, or leaves, the groove18, during bending operations. The cross-sectional view inFIG.4is made at the position of the glued anchor15, and the indent14, which is best seen inFIG.5. The glue anchor15comprises a holding part17positioned between the groove18and the central passage12.

The segment22comprises a circumferential wall23extending from an outer surface23′ to an inner surface23″. The central passage12, an electrical wire bundle groove7′, and the steering wire grooves18define, at least in part, the inner surface pf the circumferential wall23. The electrical wire bundle groove7′ and the steering wire grooves18can be said to be cut-outs in the wall23extending from the periphery of the central passage12. As shown, the central passage12has a circular shape. Other shapes, such as oblong, are also permissible. A working channel tube6′ is positioned in the central passage12and comprises at least a portion of the working channel6. An electrical wire bundle7is positioned in the electrical wire bundle groove7′. The steering wires25may be arranged inside coil springs27. A ledge16supports the anchors15, as described below.

The glue anchor15shown inFIGS.4-6may be made from a hardened adhesive which fills an indent14made in a segment22.FIG.4shows a cross-sectional view of a segment22, where two indents14are made. The indents have been filled with a glue or adhesive, which have been hardened, and thereby form the anchors15.FIG.5shows the bending section20from one side, whereby one indent14in the segment22can be seen. The anchor15, made from a hardened transparent adhesive/glue, is placed in this indent14.FIG.4shows that a similar anchor15may be placed at two opposite sides of the bending section20, one anchor for each steering wire25.

The anchors15have a hole15′ and a holding part17extending from the hole15′ into the space between the steering wire25and the central passage12. These holding parts17of the anchors prevent displacement of the steering wires25in the direction toward the central passage12. The holding parts17can completely or partially surround the coil springs27. If partially, they should surround enough of the periphery of the coil springs27so that any gap is smaller than the diameter of a coil spring27. The hole15′ receives or is formed around the steering wire25and, if present, the coil spring27.

It is shown inFIGS.4-6that the steering wires in the bending section may be arranged inside the coil springs27. The coil springs27with the steering wires25are each arranged in a groove18, and the anchor15is arranged to block displacement of the coil springs27, and thereby the steering wires25, from the grooves18towards a center of the central passage12. This reduces the risk of the steering wires moving into the narrow space between the working channel6and the inner surface23″ of the bending section20. This may be advantageous for the segments22where no anchors15are arranged. If the springs27are part of the design, the holding part17of the anchors will extend into the space between the springs27and the working channel6.

The use of springs27for guiding or enclosing the steering wires through a bending section where grooves18, i.e., the dedicated lumen for steering wires, are in open connection to the lumen for the working channel, is described further in commonly owned U.S. Patent Publication No. 2022/0233054A1; the disclosure of said publication is incorporated by reference herein in its entirety, and works for a two-way bending endoscope.

The spring27is made from a wound wire, e.g., a steel wire. The distance between two neighboring windings of the spring27may be referred to as the pitch of the spring27. So, the minimum pitch is similar to the diameter of the wire used for the spring. The pitch should be selected so that the springs can both be compressed and extended during bending of the bending section. The pitch may also vary, so that it is low in segments where an anchor15is placed, and higher in other positions. A low pitch may prevent liquid glue from entering between the windings and adhere to the steering wire during the gluing process providing a glued anchor. The pitch may be at a minimum in places where an anchor is to be placed. However, if the liquid glue has a high viscosity, the pitch may be larger than the minimum and still prevent the glue from getting in contact with the steering wire.

The steering wires25may, alternatively, be moveably arranged through the anchors15without the springs27. In that case, it must be ensured that there is no adherence between the steering wire and the anchors in manufacturing. This can be ensured by applying a lubricant to the steering wire25. This may be applied before application and hardening of the glue. The glue and the steering wire material may also be selected so that there will be no adherence. In that case the lubricant might not be necessary but may still be advantageous for lowering the friction between steering wire and hardened glue.

In another variation, an insert anchor15ais placed in the indent. The insert anchor15ahas a hole15′ for the steering wire and may comprise a portion shaped to fit in the groove. The insert anchor15amay have the same shape as the glue anchor15. As shown inFIG.6A, the insert anchor15ahas the hole15′, the holding part17(shown between dashed lines), an inner surface15bsupporting the working channel tube, and an outer surface potentially supported by the bending cover. A cutout15dextending from the inner surface15bis configured to match a corner of the ledge16. Thus, the insert anchor15amay be placed in an indent14located between the proximal and distal surfaces22a,22bof a segment, or may be placed in an indent14located at the proximal end or the distal end of a segment, by translating the insert anchor15ainto the indent14. The shape of the insert anchor15ais configured to support itself, fully or mostly mechanically, in the indent14, although glue can assist. The adhesive may be avoided, if the press fit and the bending cover hold the insert in place, particularly since the steering wire prevents the insert from falling out of the indent.

In a further variation shown inFIG.6B, small cylinders15a′ are placed in the indents and the steering wires are threaded through the small cylinders. The glue or adhesive bonds to the small cylinders instead of the wire coils27or the steering wires25. The cylinders may be made of metal and may comprise a textured surface or a chemically treated surface to aid in such adhesive bonding.

Therefore, as described above, the holding part17may be comprised of a solidified adhesive surrounding the steering wire or the coil or the small cylinder directly, or an insert anchor.

The anchors15shown inFIGS.4-6are relatively large compared to the size of the holding part17actively holding the steering wire in the grooves18. One reason for this is that bending sections20molded in one piece from a polymer material are often made from Polyoxymethylene (POM), and most glues do not adhere very well to POM. Therefore, the geometry of the anchor15, made from hardened glue, may be such that the anchor is kept in the correct position in the indent14of the segment22, also if the glue does not adhere to the bending section material. This may be achieved by a ledge or wing16extending between part of the anchor15and the central passage12. The ledge16may be formed in one piece with the segment and the rest of the bending section and may be molded from the same fused polymer material. The ledge16can thus support the anchor15and is adapted to keep the anchor15in the correct position. As shown, ledges16are connected to a central ledge portion16′ and together therewith provide part of the inner surface23″ of the wall23and the circumference of the central passage12. The ledges16are thin relative to the central portion16′, whereby the central portion16′ extends from the inner surface23″ to the outer surface23′ and the wings16extend from the inner surface23″ to somewhere intermediate the inner surface23″ and the outer surface23′. In another example, the central portion16′ does not extend to the outer surface23′ and the two anchors15may connect each other, potentially allowing insertion of glue or adhesive at a single point. The glue anchors may fill the indent to form the holding part17. The glue anchors may also fill the grooves18to form a holding part17that extends longitudinally from the indent into the groove. This provides an even stronger holding part. The glue does not need to completely fill the space between the spring coil and the central channel, it suffices that the holding part is sturdy enough to retain the spring coil and/or steering wire at the particular longitudinal position of the bending section where it is placed, Thus, the holding parts can differ in shape. The wall of a segment has a proximal surface and a distal surface, and the indent is positioned between the proximal surface and the distal surface. A surface of the ledge may form part of the proximal or distal surface of the segment, the indent extending inwardly from such surface so that the indent is positioned between the proximal surface and the distal surface. The indent can also be a cut-out in the wall with no surface of the indent forming part of the proximal or distal surface of the segment.

Also, to the extent that there is some adherence between the bending section material and the glue anchor15, increasing the contact area between the two, which is also done by the ledge16, will improve the stability of the anchor position.

For the glued anchor, the indent may be placed in a segment with the segment limiting the indent both in the distal and in the proximal direction. This may make it simpler to control where the glue is flowing during the gluing process. The indent may, therefore, be molded in an intermediate area of a segment rather than on a proximal or distal side thereof, as shown inFIG.5, where a segment22ais longer than the segments22and includes the indent14between its proximal and distal ends. The same is shown inFIG.6, where the segment22ais sectioned across the central ledge portion16′ to better show the anchors15.

It should be noted that the bending section20may often be provided with a bending cover21on the external side. This provides a watertight barrier towards the surroundings of the endoscope insertion cord3. This bending cover21may have some effect on supporting the anchor15in the correct position. The effect may, however, be relatively small as the bending cover is often very flexible and not glued to the bending section except perhaps at the proximal and distal ends thereof.

For the glue anchor a UV curing glue may be applied, as curing can happen immediately, and thereby limiting the time for the glue to flow into unwanted places inside the bending section. The glue for the anchor15may be applied from the outside of the bending section20, e.g., using a small needle tip for precise application. Viscosity of the glue may be selected to be low enough for the glue to flow in between the steering wire25and the working channel tube6′ to form the holding part17. Also, the viscosity of the glue may be selected to be high enough to avoid glue flowing into unwanted parts of the bending section via capillary forces. Also, it may be easier to create a smooth surface on the outside of the anchor15, i.e., the external side of the bending section, with a higher viscosity glue with higher surface tension.

As indicated above, one way to make the anchor15is to first insert the working channel tube6′ and the wire coils27in the bending section and then apply the glue or adhesive so that it can form the holding part17. To make the indents14in an injection molding process, a mandrel is positioned inside a, for example, two-part mold. The two-part mold includes surfaces to form the outer wall surface23′ and protrusions extending perpendicularly therefrom into the cavity formed by the two-part mold. Some of the perpendicular protrusions form the gaps between segments that define the hinges and some of the perpendicular protrusions form the indents. A protrusion can also form the segment gaps and provide indents on the proximal and/or distal surfaces of the adjacent segments. The mandrel is mostly cylindrical but has a longitudinal protrusion for forming the electrical wire bundle channel7′ and two longitudinal protrusion for forming the grooves for the steering wires25and/or the wire coils27. After the molten polymer is injected into the cavity and solidified, the mandrel is pulled out from the formed bending section and the two sides of the two-part mold are pulled out, removing the protrusions from the formed indents14and from the gaps between the segments.

Two anchors can be positioned at a same longitudinal position in the bending section. Two anchors can also be positioned in different longitudinal positions in the bending section. The indents for the anchors can be placed together with or independently of the segment gaps.FIG.6Cshows a bending section from two sides. A proximal section20aof the bending section20extends from the proximal end, and a distal section20bextends from the proximal section20ato the distal end. The lower view shows the same bending section as the upper view but the bending section has been rotated about its longitudinal axis 180 degrees. Nearest the proximal end are two anchors15positioned on opposite sides of a plane traversing a hinge and at the same longitudinal position. Further from the proximal end are two anchors15positioned on opposite sides of the plane but at different longitudinal positions. These anchors are positioned in indents that replace segment gaps. To this end the mandrel has an indent making protrusion intermediate two segment gaps. The length of the bending section includes the proximal and distal ends. The proximal section20amay be, preferably, 60% of the bending section length. The anchors are preferably positioned in the proximal section20a.

FIGS.7-12show an embodiment where the anchor15is made from a disc35. The shape of the disc may be like the Greek letter omega, of horse-shoe shaped, or U-shaped. This disc is arranged in an indent14, where the indent may be in a segment22as shown inFIGS.10and11, or the indent may be in a hinge24connecting two segments22, as shown inFIGS.7and9. Preferably, the disc35may comprise an anchor part15for each of the two steering wires, or, alternatively, the disc35may only have an anchor part for one of the steering wires25.

The disc35is preferably made from a hard material, e.g., a metal such as steel. The disc may also be made from a relatively hard polymer, e.g., polycarbonate (PC), polystyrene (PS), or polyamide (PA). The thickness of the disc may depend on the material. For steel the thickness may be in the range 0.1-0.5 mm, preferably 0.1-0.3 mm. If the material is a polymer the thickness may be above 0.3 mm.

The disc35may be shaped so that an outer circumference36of the disc is level with an outer surface formed by the parts of the bending section segments22and the hinges24facing opposite to a central passage12of the bending section20. This outer surface may also in this embodiment be covered by a bending cover21.

The disc35is provided with a holding part17′ extending into the space between the steering wire25and the working channel tube6′ such that displacement of the steering wire25, and maybe also the spring27, in a direction towards the working channel6, or a center of the central passage, is prevented.

When the disc35is arranged in an indent14in a hinge24, this may limit the angle by which the two neighboring segments, being next to this hinge, may be able to bend relative to each other. For some applications of the endoscope such a limitation may be acceptable. If the bending section is provided with many hinges, e.g., 20 or more, this limited bendability of maybe two pair of hinges might not affect the overall bending performance significantly.

FIGS.8and9shows a variation of the embodiment where the anchor15′ is a disc35. In this variation passages37for the steering wires, and e.g., also for the springs, are provided as closed holes. This means that the steering wires and e.g., the springs will need to be threaded through these holes.

Alternatively, another variation of the anchor15″ provided as a disc35, is shown inFIGS.10-13. In this variation the passages37′ are not closed, but open at one side, so that the disc35can be inserted into the indent14after the steering wires25, and e.g., the springs27, have been arranged in the grooves for the steering wires25, and e.g., the springs27. In this variation the indents are preferably made in a segment22of the bending section.

It is a possible to combine different types of anchors at different positions in the same bending section. The anchors could, in general, be the examples provided above, but it could also be other types or designs of anchors.

The number and positions of anchors along a proximal-distal direction of the bending section may depend on the total length of the bending section, the outer diameter of the bending section, the maximum bending angle of the distal end of the bending section relative to the proximal end of the bending section, and on the necessary pulling force on the steering wires to obtain this bending angle.

For example, an ureteroscope may have a bending section with a length of more than 35 mm, maybe more than 45 mm. The outer diameter may be around 3 mm or below 3 mm. The maximum bending angle may be around 270 degrees, maybe in the range 225-270 degrees. When a ureteroscope is used in a procedure in a kidney, it may often happen that the bending section has a first curvature38in the proximal half length of the bending section going in one direction, and at the same time needs to bend the distal end of the bending section in the opposite direction, resulting in a second curvature39. This is illustrated schematically inFIG.14, where a resulting S-shaped curvature of the bending section can be seen.

This means that there will be a relatively high force on the steering wire25to the convex side of the first curvature38or proximal bending curve, as this steering wire25needs to be pulled to bend the distal end of the bending section into the second curvature39. This force is directed towards a center of the central passage of the bending section. In general, the force on the steering wire25will tend to move it towards the line A-B. The circle c indicates the area where the force towards the line A-B is maximum for the steering wire25. Therefore, anchors15,15′,15″ may be placed in the part of the bending section where this area with the maximum force is likely to be during a procedure.

Looking at the bending of the bending section shown inFIG.14, it is realized that the other steering wire25′ placed to the concave side of the first curvature38, will be affected by a relatively smaller force, since this steering wire does not have to be pulled to bend the distal end of the bending section into the second curvature39. Also, the force on the other steering wire25′ in the first curvature38is directed towards the groove18and the circumferential wall23of the segments22, which will be more resistant towards any unintended displacement of the steering wire compared to the working channel6.

The above-mentioned embodiments or variations of the anchor, and how the anchor is arranged and connected to the bending section, are not limiting for the scope of this disclosure. Other designs, arrangements and connections of the anchor are possible within the scope of the claims.

The following items are further variations and examples of the embodiments described with reference to the figures.1. An endoscope comprising: a handle; an insertion cord extending from the handle and including a bending section molded in one piece, the bending section comprising: segments connected to each other by hinges, the hinges allowing two neighboring segments to bend relative to each other in a bending plane, the segments and the hinges form an outer surface of the bending section, a central passage passing each segment and extending from a distal end to a proximal end of the bending section, where each segment has a circumferential wall, the circumferential wall has an inner surface facing and encircling the central passage, at least two grooves extending from the inner surface into the circumferential wall, the grooves extending in parallel with the central passage and in open connection with the central passage, the central passage and the grooves extending through the segments of the bending section, an indent extending from the outer surface into at least one segment or in at least one hinge; two steering wires extending from the handle to the distal end of the bending section, each steering wire passes in a respective one of the grooves through the bending section; wherein an anchor is arranged in the indent, the anchor being provided with a holding part such that displacement of the steering wires from the grooves towards a center of the central passage is blocked.2. The endoscope according to claim1, wherein anchors are placed in at least two indents in segments, or next to segments, placed in the 60% of the bending section length extending from the proximal end of the bending section towards the distal end.3. The endoscope according to claim2, wherein at least two segments are provided with anchors such that displacement of the two steering wires is blocked.4. The endoscope according to claim2or3, wherein at least two segments provided with anchors are separated by at least one segment without an anchor.5. The endoscope according to claim1, wherein each anchor has a holding part extending into a space where the groove and the central passage meet.6. The endoscope according to claim1, wherein the steering wires in the bending section are passing inside coil springs, the coil springs with the steering wires are each arranged in a groove, and the anchor is arranged to block displacement of the coil springs, and thereby the steering wires, from the grooves towards a center of the central passage.7. The endoscope according to claim1, wherein the anchors having an exterior surface being level with an outer surface of a segment and the anchors having an interior surface being level with the inner surface.8. The endoscope according to claim1, wherein the anchors are made from hardened glue.9. The endoscope according to claim8, wherein a ledge is extending from the segment between the indent and the central passage, the ledge is supporting the anchor.10. The endoscope according to claim1, wherein the anchors are made from a metal disc.11. The endoscope according to claim1, wherein anchors are arranged in at least two segments, and in less than 40% of the segments, alternatively in less than 30% of the segments.12. A method for assembling an endoscope according to any one of the previous claims, comprising: providing a bending section molded in one piece from a fused polymer, and having: segments connected to each other by hinge members, the hinges allowing two neighboring segments to bend relative to each other in a bending plane, the segments and the hinges forms an outer surface of the bending section, a central passage passing each segment and extending from a distal end to a proximal end of the bending section, where each segment has a circumferential wall, the circumferential wall has an inner surface facing and encircling the central passage, at least two grooves extending from the inner surface into the circumferential wall, the grooves extending in parallel with the central passage and in open connection with the central passage, the central passage and the grooves extending through the segments of the bending section, an indent extending from the outer surface into at least one segment or in at least one hinge; arranging two steering wires to extend from the handle to the distal end of the bending section, such that each steering wire passes in a respective one of the grooves through the bending section; arranging an anchor in the indent, where the anchor is provided with a holding part such that displacement of the steering wires from the grooves towards a center of the central passage is blocked.13. A system comprising an endoscope according to any one of claims1-11, a monitor and a control unit.