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[0001] The invention relates to a flexible endoscope shank with a shank body which, viewed in the longitudinal direction of the endoscope shank, is composed of at least two shank portions with different degrees of flexibility, wherein at least one shank portion is composed of at least one spring element, and wherein all the spring elements of the shank portions, which, viewed in the longitudinal direction of the shank body, are arranged proximally from the outer distal shank portion, are designed as reversibly deformable spring rods extending in the longitudinal direction of the shank body. The invention further relates to an endoscope having a flexible endoscope shank of the kind mentioned above.

[0002] Flexible endoscopes, that is to say endoscopes with a flexible endoscope shank, are used in medicine and for technical purposes, in order to examine branched or looped regions in the body or to examine machine parts.

[0003] Flexible endoscopes differ from rigid endoscopes in that the endoscope shank of a flexible endoscope can adopt a bent, curved or even looped shape. By virtue of this flexibility of the endoscope shank, flexible endoscopes are particularly suitable in medicine for operating on and examining regions in the body that have branched or looped structures, for example the gastrointestinal tract or the air passages.

[0004] Various approaches to the design of flexible endoscope shanks are known in practice.

[0005] DE 199 08 152 A1 discloses an endoscope, in the endoscope shank of which flexible rods are arranged extending in the longitudinal direction. These flexible rods allow the operator to manually bend the endoscope shank to a desired curved profile before the operation, such that the endoscope shank can be advanced to the examination site through an opening in the body. On account of the stiffness of the rods, the endoscope shank permanently maintains this predefined curved profile during use.

[0006] Although this stiffness of the flexion rods, which permit the shaping of the endoscope shank, ensures an inner stiffness of the endoscope shank, as is important for the use, it also limits the possible applications of a flexible endoscope of this design, since the predefined curved profile of the endoscope shank cannot be changed during the operation, for example in order to examine lateral branches or the like.

[0007] A flexible endoscope of the type in question is known from EP 1 658 805 B1. In this known flexible endoscope, the endoscope shank is composed of several shank portions, which are each formed by a helical spring. The degree of flexibility of the individual shank portions can be individually adjusted by the choice of different helical springs. The reversibly deformable helical springs of this known endoscope permit a flexible endoscope shank that can be adjusted in each desired direction even during the examination.

[0008] Designing the spring elements of the individual shank portions as helical springs has the disadvantage that cleaning the narrow helical-spring threads is quite complex. In addition, the production of the different helical springs is very elaborate and cost-intensive.

[0009] Proceeding from this, the object of the invention is to create a flexible endoscope shank that is of the kind mentioned at the outset and that can be produced simply and cost-effectively.

[0010] According to the invention, this object is achieved by virtue of the fact that, viewed in the longitudinal direction of the shank body from the distal end to the proximal end, each of the shank portions having at least one spring rod has at least one further spring rod, which is integrally bonded to the other spring rods of the respective shank portion.

[0011] By designing the spring elements as spring rods made from flat or round spring wire, the shank body can be produced simply and cost-effectively.

[0012] In order to increase the dimensional stability and torsional stiffness of the individual shank portions toward the proximal end of the shank body, each shank portion, viewed in the longitudinal direction of the shank body from the distal end to the proximal end, has at least one additional spring rod, which is integrally bonded, in particular by laser welding, to the other spring rods, wherein the at least one additional spring rod of the respective shank portion is arranged laterally on the spring rod coming from the previous shank portion.

[0013] In a practical embodiment of the invention, it is proposed that the at least one further spring rod, extending in the longitudinal direction of the shank body, is arranged laterally on the other spring rods of the respective shank portion.

[0014] Furthermore, the invention proposes that each shank portion of the shank portions arranged proximally from the outer distal shank portion, when viewed in the longitudinal direction of the shank body, has at least two spring rods, each of which has a longitudinal extent reaching as far as the proximal end of the shank body. The use of at least two spring rods for the non-distal shank portion permits the design of a shank body that has a sufficient bending strength and shear stability.

[0015] Furthermore, the invention proposes that the spring rods of each shank portion are wound helically about each other and/or are wound helically about the spring rods of the shank portions which, viewed in the longitudinal direction of the shank body, are located distally. This helical winding of the spring rods about each other increases the dimensional stability, bending strength and torsional stability of the shank portions. In order to fix the spring rods to each other in the position in which they are wound about each other, and in order to prevent the winding from coming undone, it is furthermore proposed that the spring rods wound helically about each other are integrally bonded to each other at some areas, preferably punctual, preferably by laser welding, wherein the properties of the individual shank portions can be varied by means of the spring rods, wound about each other, being welded to each other only at a few locations or at many locations.

[0016] Winding the spring rods about each other also has the advantage that, upon bending of the endoscope shank, there is no preferred bending direction, and instead the endoscope shank can be bent with approximately the same force in all directions.

[0017] According to the invention, the properties of the individual shank portions, for example in respect of the degree of flexibility and the bending strength, can be varied, inter alia, by virtue of the fact that the spring rods of the individual shank portions are wound with the same or a different number of windings about the spring rods of the shank portions which, viewed in the longitudinal direction of the shank body, are located distally or proximally. More windings per unit of length result in a stiffening of the shank portion, whereas fewer windings per unit of length make the respective shank portion more flexible.

[0018] According to a preferred embodiment of the invention, it is proposed that the degree of flexibility of the spring elements of the individual shank portions decreases from the distal end to the proximal end, that is to say the outer distal shank portion is the most flexible, and the shank portions become increasingly stiffer toward the proximal end of the shank body.

[0019] According to a further embodiment according to the invention, it is proposed that the outermost distal shank portion is composed of individual segments connected to each other in an articulated manner.

[0020] For pivoting the outer distal shank portion, the invention proposes that the outermost distal shank portion is pivotable via a pull mechanism, preferably at least one Bowden cable, engaging on the distal shank portion.

[0021] For the design of the finished endoscope shank, the invention proposes that all the shank portions can be enclosed by an elastic outer sheath, preferably a hose.

[0022] The invention furthermore proposes that work channels, extending in the longitudinal direction of the shank body, are arranged in the outer sheath, for example for receiving optical components, additional medical instruments, electrical lines and the pull mechanism.

[0023] The invention further relates to a flexible endoscope having a flexible endoscope shank constructed in the manner described above.

[0030] The illustration in FIG. 1 shows a flexible endoscope 1 with a long flexible endoscope shank 2, at the proximal end of which a handle 3 is arranged.

[0031] The flexible shank 2 has a distal shank portion 4, a middle shank portion 5, and a proximal shank portion 6. Work channels (not shown) are arranged in the endoscope shank 2 and are used, for example, to receive optical fibers of the endoscope optics system, electrical lines and/or medical instruments.

[0032] As will be seen from FIG. 2, the outermost distal shank portion 4 is particularly flexible and is able to pivot in different directions. The pivoting of the distal shank portion 4 is effected via a pull mechanism 7 (shown in FIGS. 3 and 4) and a control device 8 arranged on the handle 3, which control device 8, in the illustrative embodiment shown in FIG. 1, is designed as an adjustment lever 9, which is adjustable in the direction of the arrows 10.

[0033] The handle 3 also has, at the proximal end, an eyepiece 11 and, at the distal end of the handle 3, a work channel entrance 12 through which, for example, a medical instrument can be introduced into a work channel of the endoscope shank 2.

[0034] As will be seen from FIG. 2, the distal shank portion 4 of the endoscope shank 2 can be deflected up and down through almost 180° from the straight-ahead position shown in FIG. 1. Further deflections of up to 210°, and deflections of the distal shank portion 4 in more than just two directions, are also possible.

[0035] The deflection of the distal shank portion 4 is effected via a pull mechanism 7, which engages on the distal shank portion 4 and which, in the embodiment shown in FIG. 3, is composed of two Bowden cables 13 secured on the distal shank portion 4, which Bowden cables 13 are secured at the proximal end on the control device 8 of the handle 3. By actuation of the adjustment lever 9 of the control device 8 in the direction of the arrows 10, the distal shank portion 4 is pivoted up or down in the desired direction.

[0036] For deflecting the distal shank portion 4 in more than two directions, the control device 8, in an alternative embodiment of the endoscope 1, has two adjustment levers 9: one adjustment lever 9 for pivoting the distal shank portion 4 up and down, and one adjustment lever 9 for pivoting the distal shank portion 4 to the right and left. With these two adjustment levers 9, all directions are then also possible by combination of these pivoting directions.

[0037] The structure of the shank portions 4, 5 and 6 is described in more detail below with reference to the illustrations in FIGS. 3 to 5.

[0038] To give the endoscope shank 2 the required flexibility and at the same time sufficient bending strength and shear stability, all the shank portions 5, 6 arranged proximally from the outer distal shank portion 4, when viewed in the longitudinal direction of the shank body, have reversibly deformable spring elements 14.

[0039] In the embodiments shown in the illustrations in FIGS. 3 to 5, all spring elements 14 of the shank portions 5, 6 arranged proximally from the outer distal shank portion 4, when viewed in the longitudinal direction of the shank body, are designed as reversibly deformable spring rods 15 extending in the longitudinal direction of the shank body.

[0040] In all of the embodiments shown, the outermost distal shank portion 4 is composed of individual segments 16 connected to each other in an articulated manner.

[0041] In the embodiment shown in FIG. 3, the distal shank portion 4, for attachment to the pull mechanism 7, is mounted between two Bowden cable holders 17 at the distal end and proximal end, wherein the proximal Bowden cable holder 17 serves as an abutment for the Bowden cable sheath, while the Bowden cable itself is mounted on the distal Bowden cable holder 17. By actuation of the control device 8 on the handle 3, the distal shank portion 4 can in this way be pivoted up and down.

[0042] The middle shank portion 5 of this depicted embodiment is composed of two spring rods 15, which are integrally bonded to the proximal Bowden cable holder 17 of the distal shank portion 4. As will also be seen from FIG. 4, the two spring rods 15 of the middle shank portion 5 are wound helically about each other and, further on in the longitudinal direction of the middle shank portion 5, are connected to each other and mutually fixed at some areas, preferably punctual, by weld spots 18. The integral bonding of individual spring rods 15 to each other is preferably effected by means of laser welding.

[0043] By means of the spring rods 15 being wound helically about each other, the bending strength and torsional stability of the shank portions 5, 6 so configured are increased. Winding the spring rods 15 about each other also has the advantage that, upon bending of the endoscope shank 2, there is no preferred bending direction, and instead the endoscope shank 2 can be bent with approximately the same force in all directions.

[0044] The illustration in FIG. 4 shows an enlarged and schematic detailed view of part of the middle shank portion 5 and of the proximal shank portion 6, as can be used for the design of the distal shank portion 4 described above with reference to the illustration in FIG. 3.

[0045] At the transition to the proximal shank portion 6, a third, additional spring rod 15 is integrally bonded to the two spring rods 15 of the middle shank portion 5, preferably by means of laser welding. As will also be seen from FIG. 4, the additional spring rod 15 of the proximal shank portion 6, extending in the longitudinal direction of the shank body, is arranged laterally on the spring rods 15 coming from the previous middle shank portion 5 and is wound helically about the two spring rods 15 of the middle shank portion 5 and, further on in the longitudinal direction of the proximal shank portion 6, they are connected to each other and mutually fixed at some areas, preferably punctual, by weld spots 18.

[0046] For designing the spring elements 14 designed as spring rods 15, both flat and also round metal springs, preferably of spring steel, can be used. Round spring rods 15 have the advantage that they have no preferential direction upon bending, whereas flat spring rods 15 are able to be easily bent only in two directions.

[0047] In the illustrative embodiments shown, the endoscope shank 2 is composed of three shank portions 4, 5 and 6. Alternatively, it is of course also possible for the shank to be constructed from just two shank portions or from more than three shank portions. The structure of the individual shank portions is advantageously such that the degree of flexibility of the individual shank portions decreases from the distal end to the proximal end, starting from the most flexible, distal shank portion 4, that is to say the shank portions become increasingly less flexible or stiffer.

[0048] The degree of flexibility of the individual shank portions 5 and 6 relative to each other can be adjusted by the choice of material and the geometry (length, shape, diameter) of the spring rods 15, the number of the spring rods 15 and/or the number of the windings of the spring rods 15 about each other and/or the number and position of the weld spots 18.

[0049] The helical winding of the spring rods 15 about each other can be configured in each shank portion 5, 6 with the same number or a different number of windings, and with the same pitch or a different pitch of the windings. More windings per unit of length result in a stiffening of the shank portion 5 or 6, whereas fewer windings per unit of length make the respective shank portion 5 or 6 more flexible.

[0050] The use of the spring rods 15 as spring elements 14 permits simple and cost-effective production of the flexible endoscope shank 2, such that the latter can even be produced and used as a disposable article.

[0051] As is shown schematically in FIG. 5, the shank portions 4, 5 and 6 can be enclosed by an elastic outer sheath 19, preferably a hose. This outer sheath 19 then surrounds the spring elements 14 and segments 16, and also the work channels arranged coaxially with respect to the spring elements 14. The outer sheath 19 is advantageously designed such that the work channels, extending in the longitudinal direction of the endoscope shank 2, are formed directly in the material of the outer sheath 19, as a result of which the assembly of the endoscope shank 2 is made much easier.

[0052] According to an alternative embodiment of the endoscope shank, the spring elements 14 and segments 16, and also the work channels arranged coaxially with respect to the spring elements 14, are covered by a kind of net stocking, which is then encased subsequently by the outer sheath 19.

[0053] A flexible endoscope shank 2 constructed in the manner described above is characterized in that, while being of a simple design and being able to be produced cost-effectively, it has the required flexibility, in particular in the distal shank portion 4, at the same time with sufficient bending strength, shear stability and torsional stability.

List of reference signs
1	endoscope
2	endoscope shank
3	handle
4	distal shank portion
5	middle shank portion
6	proximal shank portion
7	pull mechanism
8	control device
9	adjustment lever
10	arrow
11	eyepiece
12	work channel entrance
13	Bowden cable
14	spring element
15	spring rod
16	segment
17	Bowden cable holder
18	weld spot
19	outer sheath