This application claims priority from and the benefit of European Patent Application No. 21204436.6, filed Oct. 25, 2021; said application is incorporated by reference herein in its entirety.
The present disclosure relates to a steerable endoscope having a bending section and a distal tip part, and a method of assembling such an endoscope.
Endoscopes are well known for visually inspecting inaccessible places, such as human body cavities. Typically, the endoscope comprises an elongated insertion cord with a handle at the proximal end, as seen from the operator, and visual inspection means, such as a built-in camera, at the distal end of the elongated insertion cord, and an insertion tube extending between the handle and the visual inspection means. Endoscopes in the present context also include laryngoscopes and endotracheal tubes provided with a camera for surveillance of correct positioning.
As the name indicates, endoscopes are used for seeing inside things, such as lungs or other human body cavities of a patient. Modern endoscopes are therefore typically equipped with a light source and a vision receptor including a vision sensor, such as a camera or an image sensor. Provided that sufficient light is present, it is possible for the operator to see, where the endoscope is steered and to set the target of interest once the tip has been advanced thereto. This therefore normally requires illumination of the area in front of the distal tip part of the endoscope, in particular the field of vision of the camera(s). The light source, such as a light-emitting diode or an optical fibre, may provide illumination.
Electrical wiring for the camera and other electronics, such as LED lighting accommodated in the tip part at the distal end, runs along the inside of the elongated insertion cord from the handle to the tip part. Instead of using cameras, endoscopes may also be fibre-optic, in which case the optical fibres run along the inside of the elongated insertion cord to the tip part. For some applications, a working or suction channel may run along the inside of the insertion cord from the handle to the tip part, e.g. allowing liquid to be removed from the body cavity, allowing for injection of fluid into the body cavity, or allowing for insertion of surgical instruments or the like, into the body cavity. The suction channel may be connected to a suction connector, typically positioned at a handle at the proximal end of the insertion cord. For other applications, the working or suction channel may be omitted.
In order to be able to manoeuvre the endoscope inside the body cavity, the distal end of the endoscope may comprise a bending section with increased flexibility, e.g. an articulated tip part allowing the operator to bend this section. Typically, this is done by tensioning or slacking steering wires also running along the inside of the elongated insertion cord from the articulated tip part to a control mechanism of the handle. Furthermore, a working channel may run along the inside of the insertion cord from the handle to the tip, e.g. allowing liquid to be removed from the body cavity or allowing for the insertion of surgical instruments or the like into the body cavity.
A general desire in the field of endoscopy is to miniaturise the insertion cord of the endoscope and thus the tip part, as this may open new fields of application. In certain types of endoscopy procedures, such as ureteroscopy, an endoscope with an outer diameter of no more than 3 mm is required. Alternatively, such miniaturising may allow for the provision of a larger working channel diameter, thus expanding the range of tools that can pass through the working channel, while maintaining the same outer diameter of the endoscope. However, it has been found that especially for small endoscopes with an outer diameter around or below 3 mm, such as for instance a ureteroscope, fastening of the steering wires at the distal end of the bending section is difficult due to the limited space and due to the difficulties of gluing to the material of the bending section, which in a single-use endoscope typically is an integrally moulded and flexible part.
A further general desire in the field of endoscopy is to electrically insulate the insertion cord, and thus especially the tip part, from the outside, so as to mitigate the risk of an insulation breakdown and a resulting excessive leakage current.
Another general desire in the field of endoscopy is to provide a distal tip part, which is liquid-sealed, so as to mitigate liquid ingress into the tip part, and specifically into any electrical or optical components of the tip part.
On this background, it may be seen as an object of the present disclosure to provide an improved tip part for an endoscope alleviating or meeting at least some of the above-mentioned desires.
One or more of these objects may be met by aspects of the present disclosure as described in the following.
A first aspect of this disclosure relates to an endoscope for visually inspecting inaccessible places, such as human body cavities, the endoscope extending along a proximal-distal axis from a handle to a distal tip part, the endoscope comprising:
wherein a distal segment of the at least one steering wire is fixed to a wire portion of the interior housing part so that manipulation of the control device causes bending of the bending section.
In conventional endoscopes, the steering wire(s) is/are attached to the distal end segment of the bending section. However, the inventors of the present disclosure have found that the steering wire(s) may instead be fixed to an interior housing part of the distal tip part. Such an arrangement may provide several advantages. The material of the interior housing part is less restricted than the material of the bending section. The bending section is a high-performance part coping with relatively high tensioning forces by the steering wire(s) and straining during bending to large angles, in some cases 210 degrees or more. Therefore, the bending section is typically made of a flexible polymer, such as polyoxymethylene (POM), which is advantageous for these functions. However, the conventional materials of the bending section typically exhibit poor adhesion by adhesives and are typically opaque. Therefore, an advantage of fixing the steering wire(s) to the interior housing part is that it may be easier to adhere the steering wire(s) to the interior housing part, as the material of the interior housing part can be suitably chosen, e.g. polycarbonate. Further, an adhesive curable by ultraviolet light (UV) may be employed, as the interior housing part can be made transparent to UV light. Accordingly, the attachment of the interior housing part and the steering wires may be made stronger and have increased manufacturability.
Another advantage may be a bending section with a smaller outer diameter. Since the bending section may accommodate dedicated passages for data/power cables for the camera assembly, a working channel for insertion of tools, and dedicated steering wire lumens for retaining the steering wire(s), it is difficult also to securely fix the steering wire(s) to the bending section. As mentioned, this is especially the case when adhering the steering wire(s) to a bending section made of POM. Thus, by fixing the steering wire(s) to the interior housing part instead of the bending section, the steering wire lumens can be made open towards the working channel passage. Accordingly, the outer diameter of the bending section can be reduced.
In the context of the present disclosure, the proximal-distal axis of the endoscope may extend along a central line of the insertion cord, the bending section, and the tip part. The terms “proximal” and “distal” are understood in reference to the closeness to an operator using the endoscope. For example, the handle defines the proximal end of the endoscope, while the distal tip part defines the distal end of the endoscope. Further, the terms “circumferentially extending”, “radially extending”, and “longitudinal extending” are understood with respect to the proximal-distal axis of the endoscope.
Additionally or alternatively, the endoscope may comprise one or more cables running through the insertion tube and electrically connecting the electrical circuit of the camera assembly with the handle. The one or more cables may run in a passage of the bending section. The one or more cables may pass through one or more through-holes of the interior housing part. In particular, the one or more cables may pass through a cable passage of the proximal portion and a cable hole of the distal portion of the interior housing part. In the context of the present disclosure, the word “cable” is an insulated wire, and the word “cables” denotes a plurality of individually insulated wires, which, as a group, may or may not be enclosed in a sheath. The word “wire” is not limited to single strands, it includes single strand and multi-strand wires.
Additionally or alternatively, the exterior surface of the side wall of the exterior housing may be cylindrically shaped. An exterior diameter of the exterior surface of the side wall may define the exterior diameter of the distal tip part. The exterior diameter may be at most 3.5 mm or at most 3.2 mm or preferably at most 3.0 mm. The manufacturing complexity, and cost, may increase in an inverse proportion to the exterior diameter. For example, more advanced imaging technologies are necessary to reduce the size of the camera assembly. The imaging technologies may include logic to multiplex signals input/output to/from the image sensor to reduce the number of pads on the image sensor. The outer diameter may also limit the wire gauge that may be used. Thinner gauges, such as 36 AWG, are more susceptible to electrical noise and voltage losses and may require particularized wiring schemas. Thus, the exterior diameter may be chosen in relation to the medical procedure taking cost into consideration. This is particularly relevant for single-use endoscopes, which are discarded and not cleaned and reused. With exterior diameters of at most 3.2 mm, the image sensor may comprise only four pads and the wire gauge may be 36 AWG.
Additionally or alternatively, the exterior housing may comprise a working channel passage that may extend between a proximal opening in the proximal opening and a distal opening at the distal end of the exterior housing. The working channel passage may be separated from the interior cavity by an interior wall.
Additionally or alternatively, the interior housing part may be integrally formed as a monolithic component (e.g. moulded in one piece of material), preferably by injection moulding.
Additionally or alternatively, the exterior housing may be integrally formed as a monolithic component, preferably by injection moulding. The exterior housing may be moulded from a single material (e.g. moulded in one piece of material). Alternatively, the exterior housing may be moulded from two different materials (e.g. a transparent and an opaque material) in a single piece, by a two-component injection moulding process, for example as described in commonly-owned U.S. Pat. No. 11,291,352, which is incorporated by reference herein.
Additionally or alternatively, the bending section may be integrally formed as a monolithic component (e.g. moulded in one piece of material), preferably by injection moulding, comprising segments and living hinges connecting adjacent segments.
Such a bending section may ease the assembly as the bending section itself does not require assembly.
Additionally or alternatively, the bending section may comprise or consist essentially of a polymer, preferably flexible polymer, such as polyoxymethylene (POM).
Additionally or alternatively, each hinge member between the segments of the bending section may be a living hinge, meaning that the material of the hinge flexes to articulate adjacent segments, by contrast with hinges that connect separate segments with a pivot scheme.
Additionally or alternatively, the wire portion of the interior housing part may comprise a channel that may accommodate and/or retain the distal segment of the at least one steering wire.
This may be particularly useful during assembly, as the distal segment of the at least one wire can be placed in the channel and allow the interior housing part and at least one steering wire to be handled together without the at least one steering wire becoming loose.
Additionally or alternatively, the distal segment of the at least one steering wire may pass one or more friction-inducing sections of the wire portion that may be configured to frictionally retain the at least one steering wire in the wire portion.
This may provide the advantage of reducing or even eliminating the risk of the distal segment of the at least one steering wire sliding with respect to the wire portion.
Each friction-inducing section of the wire portion may for example be a corner, deformity, or crimp. Preferably, the one or more friction-inducing sections include(s) a plurality of corners around which the distal segment of the at least one steering wire may be bent around to increase a friction force that prevents the distal segment from sliding relative to the wire portion. The one or more friction-inducing sections may include(s) a first pair of corners that may be arranged adjacent to and on opposite sides of the channel, and about which the distal segment of the at least one steering wire bends at an angle, which may be in the range of 45-135 degrees, preferably 70-90 degrees.
Additionally or alternatively, the distal tip part may further comprise a separately formed planar element that may comprise at least one through-hole, preferably two through-holes. The planar element may be arranged between the interior housing part and the bending section. The at least one steering wire may extend through the at least one through-hole, preferably the two through-holes.
Such a planar element may ease the control of the at least one steering wire during assembly and may assist in keeping the at least one steering wire in the correct position during assembly. Furthermore, the planar element may assist in keeping the steering wire in position during full bending of the bending section.
Additionally or alternatively, the planar element may comprise or may preferably consist essentially of a stiffer material than the interior housing part. The material of the planar element may be a metal. The planar element may be formed by a sheet metal forming process, such as punching.
Additionally or alternatively, the planar element may contact a proximal end of the interior housing part.
Additionally or alternatively, the planar element may be a platelike element and/or may be shaped in the form of a disc and/or a crescent.
Additionally or alternatively, the wire portion of the interior housing part and/or the at least one through-hole of the planar element may be configured to bend a distal segment of the at least one steering wire away from the proximal-distal axis by an angle at the respective through-hole. The angle may be at least 2°, preferably at least 5°.
Such an angle may increase the friction between the at least one steering wire and the interior housing part and/or the planar element. Thereby, the maximum load on the at least one steering wire before sliding in relation to the interior housing part is increased.
Additionally or alternatively, an angle between the distal segment of the at least one steering wire and the centre line of the respective through hole may be at least 2°, preferably at least 5°. It is considered that such an angle will increase the maximum pull force on the steering wire.
Additionally or alternatively, a segment of the at least one steering wire extending immediately from the planar element and towards the interior housing part is non-parallel with respect to a centre line of the respective through-hole of the planar element.
Additionally or alternatively, the distal tip part may comprise a cured first adhesive that may adhere the circumferentially extending closure surface to an interior surface of the side wall of the exterior housing, thereby closing the interior cavity of the exterior housing and preferably liquid-sealing the gas volume of the interior cavity.
Additionally or alternatively, the closure surface of the distal portion of the interior housing part and the interior surface of the exterior housing, interior surface (65), e.g. of the interior surface of the circumferentially extending side wall, is distanced by a substantially uniform distance about the proximal-distal axis. This distance and the viscosity of the first adhesive is chosen so that capillary forces urge the liquid first adhesive to flow into the gap between closure surface and the interior surface. Further, the distal tip part is arranged so that space significantly expands on the distal side of this gap so that liquid adhesive is kept within the gap until curing and thus prevented from flowing onwards from the gap and into the interior cavity.
Additionally or alternatively, the distal tip part may comprise a cured second adhesive that may adhere the at least one steering wire to the wire portion of the interior housing part, preferably to the channel and/or friction-inducing section(s) of the wire portion.
Additionally or alternatively, the first and second adhesives may preferably be different from each other but may in some embodiments be the same. The first and second adhesives may preferably be cured at different times during assembly, i.e. the first adhesive is cured first, and the second adhesive is cured subsequently. In such a case, a border between the two adhesives may be present and intermixing of the adhesives may be avoided. However, in some embodiments, the adhesives may be cured simultaneously, for instance when the first and second adhesives are the same type of adhesive.
Additionally or alternatively, the distal end segment of the bending section may comprise a circumferentially extending outer wall that may have a proximal-distal extending cut-out. The proximal portion of the interior housing part may comprise one or more locking protrusions radially extending into the cut-out of the outer wall of the bending section so as to lock the rotation of the interior housing part with respect to the distal end segment of the bending section about the proximal-distal axis.
This may be advantageous during assembly, as the orientation of the bending section relative to the interior housing part is locked, thus reducing the risk of erroneous assembly. Furthermore, the attachment strength between the bending section and the interior housing part can be further improved by arranging the cured second adhesive around the locking protrusions in the cut-out so as to form an adhesive anchor.
Additionally or alternatively, the at least one steering wire may include a first steering wire and/or a second steering wire.
In some embodiments, the first and second steering wires may be separate from each other. In such embodiments, the distal segment of each steering wire may be attached to the wire portion of the interior housing part.
In other embodiments, the first steering wire may comprise two longitudinal segments extending in parallel along the proximal-distal axis. The first steering wire may comprise the distal segment, which may be arranged between the two longitudinal segments. Additionally or alternatively, the two longitudinal segments may extend from the handle to the interior housing part. The two longitudinal segments of the first steering wire may each comprise an end of the single steering wire. The ends of the first steering wire may be connected or attached directly to the control device of the handle. Additionally or alternatively, the distal segment may connect two longitudinal segments of the first steering wire. The distal segment of the first steering wire may be fixed to the wire portion of the interior housing part.
Additionally or alternatively, the interior housing part may include:
By adhering the bending cover to an already cured adhesive surface, an improved contact is ensured. This is in contrast to conventional endoscopes, where the distal end of the bending cover is typically adhered to the bending section, the resulting connection typically having poor adhesion.
Additionally, the bending cover may be arranged to not overlap the exterior housing. Additionally or alternatively, the bending cover may be arranged proximally of the proximal opening and/or the proximal end of the exterior housing. By arranging the bending cover in such a way, the outer diameter of the distal tip part is kept to a minimum, since the thickness of the bending cover does not enlarge the outer diameter.
A second aspect of this disclosure relates to a method of assembling a distal tip part for an endoscope preferably according to the first aspect. The method comprises the steps of:
Additionally or alternatively, the step of assembling the exterior housing, the camera assembly, and the interior housing part may comprise a first set of steps including:
Additionally, during the step of inserting the interior housing part through the proximal opening of the exterior housing, the substantially uniform gap is provided by one or more guiding protrusion(s) of the closure surface of the interior housing part. The one or more guiding protrusion(s) contacts or abuts the interior surface of the side wall of the exterior housing when the distal portion of the interior housing part is placed in the exterior housing.
Additionally or alternatively, the step of assembling the exterior housing, the camera assembly, and the interior housing part of the method of the second aspect may further comprise the steps of:
Additionally or alternatively, the step of assembling the exterior housing, the camera assembly, and the interior housing part may comprise a second set of steps, which may preferably be performed after the first set of steps. The second set of steps includes:
Additionally or alternatively, prior to injecting the second adhesive, the mould volume may comprise, a circumferentially extending gap, which may extend longitudinally between the proximal portion of the interior housing part and the circumferentially extending liquid seal of the mould. The step of injecting the second adhesive may comprise filling said circumferentially extending gap with the second adhesive. The step of causing or letting the second adhesive cure may comprise overmoulding, upon curing, a circumferentially extending cured adhesive surface onto the interior housing part between the proximal opening of the exterior housing and the proximal portion of the interior housing part. The method may further comprise a step of adhering a distal portion of a bending cover to the cured adhesive surface so that the exterior surface of the bending cover is substantially flush with the exterior surface of the exterior housing and preferably so that the bending cover covers the bending section, preferably any gaps between hinge members of the bending section.
Additionally or alternatively, the mould may be a transparent mould, preferably made of silicone, the second adhesive may be curable by ultraviolet light, and the step of causing the second adhesive to cure may include exposing the second adhesive to ultraviolet light through the transparent mould.
A person skilled in the art will appreciate that any one or more of the above aspects of this disclosure and embodiments thereof may be combined with any one or more of the other aspects of this disclosure and embodiments thereof.
Embodiments of this disclosure will be described in more detail in the following with regard to the accompanying figures. The figures show one way of implementing the present invention and are not to be construed as being limiting to other possible embodiments falling within the scope of the attached claim set.
In the following figure description, the same reference numbers refer to the same elements and may thus not be described in relation to all figures.
The bending section 40 is integrally formed by injection moulding as a monolithic component preferably made of polyoxymethylene (POM). The bending section 40 comprises articulated segments including a proximal end segment 41, a distal end segment 42, and a number of intermediate segments 43 (as best seen in
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The endoscope 1 of
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The exterior housing 60 comprises a distal end 62 with a window 67, a proximal end 69, a circumferentially extending side wall 63 with a proximal opening 61 at the proximal end 69. The circumferentially extending side wall 63 defines an interior cavity 66 with a gas volume. The exterior housing 60 has an exterior surface 64 facing the exterior of the endoscope and an interior surface 65 facing the interior cavity 66. The exterior housing 60 further comprises a working channel passage 68 extending between a proximal opening 68b in the proximal opening 61 and a distal opening 68a at the distal end 62 of the exterior housing 60. The working channel passage 68 is separated from the interior cavity 66 by an interior wall 68c. A working channel tube 34 (not shown in
The camera assembly 51 is positioned in the interior cavity of the exterior housing 60 of the distal tip part 50. The camera assembly 51 is in signal communication with a circuit (not shown) of the handle 20 via data and power cables 53 (as best seen in
The interior housing part 70 is a prefabricated component formed separately from the exterior housing 60, as best seen in
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The wire portion 76 of the interior housing part 70 comprises a channel 76a that accommodates and retains the distal segment 22b of the steering wire 22. The channel 76a extends along an arc about the proximal-distal axis PD. The channel 76a holds the distal segment 22b of the steering wire 22 during assembly.
As mentioned above, the proximal portion 73 of the interior housing part 70 comprises four locking protrusions 73a radially extending into the cut-out 45 of the outer wall 42a of the bending section 40 and locking the rotation of the interior housing part 70 with respect to the distal end segment 43 of the bending section about the proximal-distal axis PD. The proximal portion 73 further comprises the cable passage 73b for the cable 53, which cable extends from the handle and passes through the insertion tube, the bending section, and the cable passage 73b. In the present embodiment, the four locking protrusions 73a can be described, as shown, as a first pair of locking protrusions and a second pair of locking protrusions opposite the first pair. The longitudinal cable passage 73b passes between the first pair and the second pair. In the present embodiment, the channel 76a can be described as a first steering wire channel intermediate locking protrusions of the first pair and a second steering wire channel intermediate locking protrusions of the second pair. The first pair of locking protrusions and the second pair of locking protrusions traverse the longitudinal cut-out of the distal end segment. The distal segment of the steering wire traverses the first steering wire channel and the second steering wire channel.
The interior housing part 70 further comprises a separately formed planar element 80. The planar element 80 contacts, on a distal side, a proximal end 77 of the interior housing part 70, and on an opposite proximal side, the distal end segment 42 of the bending section 40, as shown in
In the present embodiment, the planar element 80 comprises opposing surfaces, a first through-hole 81 and a second through-hole 81 extending between the opposing surfaces. The steering wire includes a first segment extending from the distal segment to the handle and a second segment extending from the distal segment to the handle. The first segment and the segment pass, respectivelly, through the first through-hole and the second through-hole.
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The following items are examples of various embodiments and variations thereof disclosed above and others:
1. An endoscope (1) for visually inspecting inaccessible places, such as human body cavities, the endoscope extending along a proximal-distal axis (PD) from a handle (20) to a distal tip part (50), the endoscope comprising:
2. An endoscope according to item 1, wherein the bending section is integrally formed as a monolithic component.
3. An endoscope according to any one of the previous items, wherein the wire portion of the interior housing part comprises a channel (76a) accommodating and retaining the distal segment of the at least one steering wire.
4. An endoscope according to any one of the previous items, wherein the distal segment of the at least one steering wire passes one or more friction-inducing section(s) (76b) of the wire portion configured to frictionally retain the at least one steering wire in the wire portion.
5. An endoscope according to any one of the previous items, wherein the distal tip part further comprises a separately formed planar element (80) comprising at least one through-hole (81) and being arranged between the interior housing part and the bending section, wherein the at least one steering wire extends through the at least one through-hole.
6. An endoscope according to item 5, wherein the wire portion of the interior housing part and/or the at least one through-hole of the planar element is/are configured to bend a distal segment of the at least one steering wire away from the proximal-distal axis by an angle (76c) at the respective through-hole, the angle being at least 2°.
7. An endoscope according to any one of the previous items, wherein the distal tip part comprises a cured first adhesive (111) adhering the circumferentially extending closure surface to an interior surface (65) of the side wall of the exterior housing, thereby closing the interior cavity of the exterior housing and liquid-sealing the gas volume of the interior cavity.
8. An endoscope according to any one of the previous items, wherein the distal tip part comprises a cured second adhesive (120) adhering the at least one steering wire to the wire portion of the interior housing part.
9. An endoscope according to any one of the previous items, wherein the distal end segment of the bending section comprises a circumferentially extending outer wall (42a) with a proximal-distal extending cut-out (45), wherein the proximal portion of the interior housing part comprises one or more locking protrusion(s) (73a) radially extending into the cut-out of the outer wall of the bending section so as to lock the rotation of the interior housing part with respect to the distal end segment of the bending section about the proximal-distal axis.
10. An endoscope according to any one of the previous items, wherein the interior housing part includes:
11. A method of assembling a distal tip part for an endoscope according to any one of the previous items, the method comprising the steps of:
12. A method according to item 11, wherein the step of assembling the exterior housing, the camera assembly, and the interior housing part comprises a first set of steps including:
13. A method according to item 11, wherein the step of assembling the exterior housing, the camera assembly, and the interior housing part further comprises the steps of:
14. A method according to item 12, wherein the step of assembling the exterior housing, the camera assembly, and the interior housing part further comprises a second set of steps including:
15. A method according to any one of items 13-14, wherein the mould volume comprises, prior to injecting the second adhesive, a circumferentially extending gap (75c), which extends longitudinally between the proximal portion of the interior housing part and the circumferentially extending liquid seal of the mould,
wherein the step of injecting the second adhesive comprises filling said circumferentially extending gap, and the step of cause or letting the second adhesive cure comprises overmoulding, upon curing, a circumferentially extending cured adhesive surface (121) onto the interior housing part between the proximal opening of the exterior housing and the proximal portion of the interior housing part, and
wherein the method further comprises a step of adhering a distal portion (91) of a bending cover (90) to the cured adhesive surface so that an exterior surface (92) of the bending cover is substantially flush with the exterior surface of the exterior housing.
Number | Date | Country | Kind |
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2120 4436.6 | Oct 2021 | EP | regional |