Detachable insulating insert for use in a resectoscope

Description

background

[0001] The invention relates to an electrically insulating insulating insert of the type mentioned in the preamble of claim 1, as well as an electrode instrument and a resectoscope of the type mentioned in the preamble of claims 6 and 8 respectively.

[0002] Resectoscopes of this type, which feature appropriate electrode instruments and an insulating tip at their distal end, are primarily used in urology for electrosurgical procedures in the bladder and urethra. They are typically used for the resection and vaporization of tissue, for example, tissue in the lower urinary tract. These resectoscopes include a longitudinally adjustable electrosurgical passage instrument, which, after insertion of the resectoscope, can be advanced with its distal working end from the distal end of the resectoscope's shaft tube. The electrosurgical passage instrument may include an electrosurgical electrode at its distal working end, for example, in the form of a loop or a vaporization button (e.g., PlasmaButtons). Examples of such instruments are the OES PRO resectoscopes (Olympus) or other continuous irrigation resectoscopes developed by Iglesias.

[0003] To prevent short circuits between the active electrode and the conductive material of the shaft tube, resectoscopes typically include a section in their distal end made of an insulating material, such as ceramic, commonly referred to as an insulating tip or insulating insert. The insulating insert can be, as in Fig. 1 or 2 shown, either on the inner shaft ( Fig. 1 ) or on the outer shaft ( Fig. 2The insulating insert must be arranged in a specific way. Since the resectoscope is designed for multiple uses and must therefore withstand sterilization conditions, such as autoclaving, the insulating insert must meet high demands for durability and reprocessability in both cases. The choice of material is therefore generally limited to relatively expensive, high-performance ceramics such as silicon nitride. Furthermore, to minimize the fragility of ceramic insulating inserts, they must have a relatively thick wall.

[0004] Relevant prior art is disclosed in documents US 2005 / 080412 A1, DE 10 2013 001156 A1, DE 101 22 465 C1 and US 2002 / 188293 A1.

[0005] It would be desirable to reduce both the cost of insulation inserts and their wall thicknesses. Therefore, there is a need for correspondingly improved insulation inserts. Description

[0006] This problem is solved by an insulating insert with the features of claim 1, an electrode instrument with the features of claim 6 and a resectoscope with the features of claim 8.

[0007] According to the invention, the insulating insert is designed, in particular, as a single-use component that is detachably connected to the resectoscope shaft and can therefore be easily replaced with a new insulating insert after use. At the same time, the insulating insert is securely held to the resectoscope shaft by means of a fastening device, so that loss of the insulating insert during a procedure is impossible.

[0008] In a first aspect, the invention therefore relates to an electrically insulating insulating insert for detachable connection with the distal end region of a resectoscope shaft, characterized in that the insulating insert has a hollow section with an elongated cavity for passing through instruments and that the insulating insert has fastening means for detachable connection with the resectoscope shaft.

[0009] The insulating insert is designed to be electrically non-conductive, i.e., electrically insulating. This ensures the isolation of the active electrode from the conductive resectoscope shaft. For this purpose, the insulating insert is preferably made entirely, or at least to an extent that ensures the insulating capacity of the insert, of an electrically non-conductive, i.e., electrically insulating, material. Such materials are known to those skilled in the art and include, for example, ceramics and plastics. Insulating inserts made of plastics are particularly preferred according to the invention due to their relatively low production costs and good insulating properties. Since the insulating insert can come into contact with the plasma generated during electrosurgical treatment with an electrode, thermostable plastics are particularly preferred.Thermostable plastics are able to withstand the high temperatures generated at the distal tip of the resectoscope without damage. Suitable thermostable plastics can be selected, for example, from the group consisting of fluoropolymers and cycloolefin copolymers. The insulating inserts made of plastic can be manufactured using an injection molding process.

[0010] The insulating insert is suitable for detachable connection to the distal end of a resectoscope shaft. This means that the insulating insert and the end are at least partially complementary in shape and size. This allows the insulating insert to be connected to the end. Various possible embodiments for this connection are described elsewhere herein. In any case, the connection is so secure that detachment of the insulating insert during a surgical procedure is prevented.

[0011] Simultaneously, the connection between the resectoscope shaft and the insulating insert is designed to be detachable, allowing for easy replacement and / or cleaning of the insulating insert, for example, by medical personnel or the cleaning staff responsible for reprocessing the instrument—i.e., the end users of the resectoscope. In particular, the insulating insert is not glued to the end of the resectoscope shaft. However, this does not preclude the possibility that detaching the insulating insert from the resectoscope shaft may require standard disassembly steps for cleaning. For example, in certain embodiments of the invention, it is necessary to detach the outer shaft (sheath tube) from the inner shaft with the inserted electrode instrument before the insulating insert can be detached from either the inner or outer shaft.

[0012] The connection between the resectoscope shaft and the insulating insert is made at the distal end of the shaft. Typically, the insulating insert is designed to be at least partially complementary in shape to elements of the resectoscope shaft located at its end. For example, the insulating insert, which has a cylindrical section, can be pushed onto the inner or outer tube, inserted into the inner tube, or inserted between the inner and outer tubes. The latter option is preferred. The insulating insert can, for instance, be connected to the inner tube and shaped such that the inner tube connected to the insulating insert can be inserted into an outer tube from a proximal direction.

[0013] When assembled, the insulating insert and the resectoscope shaft typically overlap, meaning they interlock. It is understood that the insulating insert should not be fully inserted into the resectoscope shaft to ensure adequate insulation of the electrode. Therefore, the overlapping area, and thus the "distal end region" of the resectoscope shaft mentioned here, will generally be limited to a distal section of a few millimeters, e.g., 10 mm or less, 8 mm or less, preferably 5 mm or less.

[0014] As mentioned, the insulating insert has a hollow section with an elongated cavity for guiding through instruments. This section is located in the proximal end region of the insulating insert. It ensures that through instruments guided by the resectoscope shaft can pass through the channel-shaped interior of the insulating insert. The insulating insert can have a substantially cylindrical shape or at least a substantially cylindrical proximal section. Accordingly, the cavity inside the hollow section can have a hollow cylindrical shape. However, the invention also envisages the possibility of designing the cavity and the corresponding section with non-circular cross-sections. For certain applications, it may be advantageous to design the cavity and / or the outer surface of the section with an elliptical or oval cross-section. Irregular cross-sections are also conceivable, e.g.Indentations or protrusions in the inner wall of the section are designed to guide specific instruments. Furthermore, the wall thickness of the section is intended to be adapted to its respective load. For example, the wall in a distally extended area can be made thicker than the wall in other areas of the insulating insert. Overall, the hollow section can be considered tubular, whereby the term "tubular," as previously described, includes not only simple hollow cylinders but also elongated sections with an outer wall and an elongated cavity within. This cavity is open at its distal and proximal ends to allow the passage of instruments. Examples of such instruments include electrodes, optics, irrigation tubes, and the like.

[0015] Furthermore, the insulating insert, particularly in its distal end region, can have conventional shapes. The walls of the insulating insert are preferably arranged within the wall cavity of a hollow cylindrical space. However, as indicated above, different wall thicknesses are also permissible within the scope of the invention. Preferably, the wall cavity has the same inner diameter as an inner tube arranged in the resectoscope shaft. In the past, the following has proven particularly effective: Fig. 1The depicted, distally extended shape for insulating tips has proven effective. The distally extended area, as well as the proximal portion of the hollow section, can have a greater wall thickness than other areas of the insulating insert. With such a "beak-shaped" insulating insert, tissue can be supported on the extended side of the insert, preventing it from collapsing into the field of view. Furthermore, this design lengthens the path of the irrigation fluid, thereby generating a more linear current that reduces the risk of turbulence in front of the optics. Simultaneously, the electrode can still cut tissue close to the edge of the insulating insert.

[0016] According to the invention, the insulating insert has one or more fastening means for a detachable connection to the resectoscope shaft. The fastening means can take on various forms and, in conjunction with the design of the distal end region of the resectoscope shaft, ensures a secure yet detachable connection. The fastening means are generally arranged in the proximal end region of the insulating insert, preferably in its hollow section.

[0017] The fastening element can, for example, comprise or consist entirely of a radial thickening of the insulating insert within its hollow section. This thickening can engage with another element on the resectoscope shaft, thereby securing the insulating insert against distal displacement. This other element on the resectoscope shaft can be, for example, an access opening or a protrusion. The thickening can be flexible, such as a snap-in element, to allow the insulating insert to be slid onto the resectoscope shaft. Alternatively, the thickening can be inflexible, for example, if the insulating insert is positioned between the inner and outer tubes during resectoscope assembly.

[0018] The radial thickening can consist, for example, of a) a larger outer diameter of the insulating insert relative to the outer diameter at the distal end of the hollow section, and / or b) a larger wall diameter of the insulating insert relative to the wall diameter at the distal end of the hollow section. In an example of a larger outer diameter according to alternative a), the insulating insert, in particular its outer wall, can be fully or partially conical in the axial direction. The outer diameter of the insulating insert at its proximal end would then be larger than its outer diameter at its distal end. In an example of a larger wall diameter of the insulating insert according to alternative b), one or more protrusions, for example in the form of pins, can be formed on the outer or inner wall of the insulating insert.The protrusion can be formed radially around the perimeter of the corresponding wall or as one or more prongs arranged radially along a circumference of the corresponding wall.

[0019] Alternatively or additionally, the fastening device can include or consist of a part of a connection commonly used in other fields. For example, the fastening device can include or consist of a part of a bayonet, screw, snap, clamp, or detent connection. The corresponding complementary part(s) of the respective connection will then be formed on the resectoscope shaft, so that a bayonet, screw, snap, clamp, or detent connection is formed between the insulating insert and the resectoscope shaft.

[0020] In one embodiment, the fastening means comprises, for example, a projecting locking element arranged on the fastening side of the hollow section. The "fastening side" here refers to the outer and inner sides of the hollow section of the insulating insert where the fastening means is located. Preferably, the fastening side of the hollow section is its outer wall. This means, for example, that in a region of the insulating insert located between the outer and inner tubes of the resectoscope shaft, the outer tube has elements for securing the insulating insert against distal displacement.

[0021] While the insulating insert is secured against axial displacement, in certain embodiments it can be rotatably arranged on the inner or outer tube, or between the inner and outer tubes. This allows the insulating insert to rotate during a procedure, making tissue accessible from different directions. The rotation of the insulating insert can be synchronized with, or coupled to, the rotation of the electrode around the longitudinal axis of the resectoscope shaft.

[0022] In a related, second aspect, the invention relates to an electrode instrument for use in a resectoscope, wherein the electrode instrument has a shaft section and an electrode at its distal end that can be subjected to high-frequency current, characterized in that the electrode instrument is connected to an insulating insert according to the invention and the electrode instrument and the insulating insert are axially displaceable relative to each other.

[0023] The electrode instruments used in resectoscopes are often designed for single use. The insulating insert according to the invention can also be designed for single use. The aforementioned connection between the electrode instrument and the insulating insert advantageously allows two potentially single-use components of the system to be offered together for exchange. Furthermore, the insulating insert can thus also assist in guiding and positioning the electrode within the shaft system. At the same time, the electrode loop can be aligned more precisely with the insulating insert. The insulating insert can also be used as a gripping element when inserting the electrode instrument connected to it, i.e., as a body on which the connected parts can be grasped.This protects the electrode instrument, especially the electrode during insertion, and improves handling for the end user.

[0024] The electrode instrument has an elongated shaft section and is designed as a through-tube instrument for a resectoscope, i.e., as an instrument that can be inserted into a body orifice through a resectoscope shaft tube. The electrode instrument has an electrode at its distal end that can be subjected to high-frequency current. The electrode can be a cutting loop, a PlasmaButton, or other commercially available electrodes. Preferably, the electrode is a cutting loop electrode. Suitable electrodes and electrode instruments are known to those skilled in the art.

[0025] The electrode instrument can be a bipolar electrode instrument, which includes the electrode as part of an electrode array. In this case, the electrode instrument will, for example, include a second electrode in the distal end of the instrument, which is designed as a neutral electrode. Alternatively, the second electrode (neutral electrode) can also be located on other elements of the distal end of the resectoscope. Of course, the electrode instrument can also be designed as a monopolar instrument.

[0026] The electrode instrument is longitudinally displaceable within the shaft of a resectoscope, meaning it can move axially both distally and proximally. For connection to the resectoscope, the electrode instrument has at least one elongated shaft, which can be attached at its proximal end to a slide enclosed by the resectoscope to create a motion-coupled connection. The slide typically slides on a tube and is held in a rest position by a spring-loaded assembly. This allows the electrode at its distal end to be moved toward or away from the tissue to be cut without having to move the entire resectoscope. Furthermore, the longitudinal displacement of the electrode instrument makes it possible to trap tissue between the electrode and the insulating insert and remove it from the surgical site.The distal end of the insulating insert and the electrode can thus be moved towards and away from each other by means of the longitudinal displacement of the electrode instrument.

[0027] According to the invention, an electrode instrument is in particular connected to an insulating insert according to the invention. The axial longitudinal displacement of the electrode instrument and the insulating insert relative to each other is not prevented by this connection. Instead, the connection ensures longitudinal displacement by a certain distance in the axial direction. This distance comprises the distance by which the electrode instrument is typically movable in the axial direction. At the same time, the movement in other directions is reduced or prevented by the connection.

[0028] The insulating insert can, for example, have one or more, preferably two, connecting elements in which a fork tube of the electrode instrument is axially displaceably mounted. The connecting element can be arranged on the inner wall of the insulating insert. To reduce material usage and optimize the fit, the connecting element(s) can, for example, be molded as a single piece with the insulating insert. Since the electrode instruments preferably have two fork tubes, it is correspondingly preferred that the insulating insert has two connecting elements in which these fork tubes can each be mounted. The longitudinal axis of the connecting elements thus extends parallel to the longitudinal axis of the insulating insert. The connecting elements are accordingly connected to the inner wall of the insulating insert via their outer wall. The connecting elements can be tubular, i.e.,They have a hollow cylindrical shape. Alternatively to these solid tubular connecting elements, the invention also allows the use of partially cylindrical connecting elements, i.e., connecting elements with a partial circular cross-section. The connecting elements can, for example, be designed as clips or clamps.

[0029] In another related aspect, the invention relates to a resectoscope for endoscopic surgery with a tubular resectoscope shaft comprising an elongated outer tube and an inner tube arranged in the outer tube, as well as a rod-shaped optic, characterized in that the resectoscope a) comprising an insulating insert according to the invention and an electrode instrument with a shaft section and with an electrode at its distal end that can be subjected to high-frequency current; or b) comprising an electrode instrument according to the invention.

[0030] The resectoscopes according to the invention can be used in all areas of endoscopic surgery. They are particularly well suited for use in narrow body channels, such as the urethra. For this purpose, the resectoscopes have the previously described tubular resectoscope shaft. The shaft can, in the usual manner, have a sheath (outer tube) and an elongated inner tube extending through the sheath, with the electrode instrument used according to the invention preferably arranged in the inner tube. The wall of the insulating insert according to the invention in its proximal end region is, as already indicated above, preferably arranged between the sheath and the inner tube extending within the sheath.

[0031] For viewing the surgical area and monitoring the procedure, the resectoscope according to the invention further comprises optics, i.e., an optical image guide. The optics run the length of the shaft and are, for example, also arranged in the inner tube. The optics can comprise an ordered fiber bundle and / or rod lenses arranged one behind the other. At its distal end, the optics have an objective lens and at its proximal end an eyepiece. The observer's eye views an area through the optics that lies in front of the distal end face of the shaft. Alternatively, the optics can also be connected to a digital image acquisition unit at its proximal end.

[0032] It is conceivable to stabilize individual components that pass through the shaft part of the resectoscope against each other, especially against displacement in the radial direction.

[0033] The electrode instrument typically has guide elements that serve to support and stabilize the electrode instrument within the inner tube. For this purpose, the guide elements abut the inner wall of the inner tube or the optics in such a way that axial movement of the electrode instrument, and potentially also rotational movements about its longitudinal axis, are possible, while radial movement of the electrode instrument is reduced or prevented. It has been found to be particularly advantageous to design the guide elements to be partially complementary in shape to the inner wall. The guide elements can, for example, have a semicircular cross-section. Such guide elements are known to those skilled in the art. The guide elements can be made of metal or other materials. Guide plates are particularly preferred. Between the electrode instrument, or...Its guide elements and the inner wall of the inner tube are generally free of any other components. However, additional components, such as optics, may be located inside the inner tube.

[0034] In addition to or as an alternative to these guide elements, the insulating insert according to the invention has connecting elements, as described above, by means of which the electrode instrument is secured radially against displacement while remaining axially movable. Within the scope of the invention, it is possible to dispense with the usual guide elements described above, since the electrode instrument is guided by the insulating insert. However, it is understood that additional stabilization by means of guide elements is also envisaged within the scope of this invention.

[0035] The resectoscope shaft typically includes elements for creating the detachable connection with the insulating insert described elsewhere, in particular for the detachable connection of the distal end of the sheath or inner tube to the proximal end of the insulating insert. These elements are functionally complementary to the fastening means of the insulating insert described above, so that together they form a detachable connection between the insulating insert and the resectoscope shaft. For example, the sheath or inner tube of the resectoscope may have an opening for a locking element of the insulating insert to create this detachable connection.Alternatively or additionally, the outer tube or inner tube can include one or more radial protrusions which, in the assembled state, prevent axial displacement of the insulating insert in a distal direction, for example, an insulating insert that has a conical shape. Brief description of the characters

[0036] The drawings schematically illustrate exemplary embodiments of the invention. They show: Fig. 1 a schematic, lateral sectional view of a prior art resectoscope in which an insulating tip is arranged on the inner tube; Fig. 2 a schematic, lateral sectional view of an alternative resectoscope from the prior art in which an insulating tip is arranged on the sheath tube; Fig. 3 a schematic, lateral sectional view of the distal end region of the in Fig. 1 shown resectoscope from the state of the art; Fig. 4a schematic, lateral sectional view of the distal end region of the in Fig. 2 shown resectoscope from the state of the art; Fig. 5 a schematic, lateral sectional view of the distal end region of a resectoscope according to the invention, which has an insulating insert with radially externally arranged fastening means; Fig. 6 a schematic, lateral sectional view of the distal end region of an alternative resectoscope according to the invention, which has an insulating insert with a conical shape in its proximal end region; Fig. 7 a schematic, lateral sectional view of the distal end region of an alternative resectoscope according to the invention, which has an insulating insert with a conical shape in its proximal end region and in which an electrode instrument is axially displaceable with the insulating insert; Fig. 8a schematic, lateral sectional view of the distal end region of an alternative resectoscope according to the invention, which has an insulating insert with a conical shape in its proximal end region, in which an electrode instrument is axially displaceably connected to the insulating insert and whose insulating insert has a locking element for additional connection between the insulating insert and the resectoscope shaft (A) and an enlargement of a section of this sectional view (B); and Fig. 9 a section of a schematic, lateral sectional view of the distal end region of a further resectoscope according to the invention, the insulating insert of which has a locking element for additional connection between the insulating insert and the resectoscope shaft, wherein the locking connection can be released without destroying the locking element. Examples of implementation

[0037] Further advantages, characteristics, and features of the present invention will become clear in the following detailed description of exemplary embodiments with reference to the accompanying drawings. However, the invention is not limited to these exemplary embodiments.

[0038] Fig. 1 Figure 1 shows a schematic, lateral sectional view of a prior art resectoscope 26 in which an insulating insert 10 is arranged on the inner tube 38. Fig. 3 shows a schematic, lateral sectional view of the distal end region of the same resectoscope from the prior art.

[0039] The resectoscope 26 has a resectoscope shaft 14 which encloses a sheath tube 36 (outer tube) shown with dashed lines. Inside the sheath tube 36 runs an inner tube 38 and inside the inner tube 38 an electrode instrument 24 as well as a Fig. 3The optics 40 shown and a light source, for example in the form of an optical fiber bundle, are included. Furthermore, other elements not shown here may be present in the resectoscopes, such as a separate irrigation tube and the like. The outer tube 36 has openings in its distal end region (not shown here) through which the contaminated irrigation fluid can flow into the space between the outer tube 36 and the inner tube 38 and out through the resectoscope shaft 14.

[0040] As in Fig. 1 and in greater detail in the Fig. 3As can be seen, the electrode instrument 24 in this conventional instrument is protected against lateral displacements, i.e., displacements deviating from the longitudinal direction of the resectoscope shaft 14, for example, transverse to the longitudinal direction, by means of a retaining element 46 (guide element) with a semicircular cross-section. The electrode instrument 24 is mounted so as to be longitudinally displaceable within the inner tube 38. The retaining element 46 is shaped to be complementary to the inner wall of the inner tube 38 or to the outer wall of the optics 40 and has a semi-cylindrical shape. The retaining element 46 is attached to two forked tubes 34 in a shaft section of the electrode instrument 24. The forked tubes 34 run close together within the resectoscope shaft 14 and only diverge in the distal end region of the resectoscope shaft 14 in order to accommodate and support a loop electrode between their ends.Alternatively, it is also conceivable that the fork tubes 34 transition into an electrode instrument shaft tube in the middle or proximal region of the resectoscope 26. In this embodiment, the retaining element(s) 46 can be arranged on the electrode instrument shaft tube.

[0041] The electrode instrument 24 can be moved axially in distal and proximal directions by actuating a handle 48. It can be extended beyond the distal end of the inner tube 38 and the outer tube 36. This allows the surgeon to manipulate tissue located further away from the resectoscope tip. For this purpose, the inner tube 38 and / or the electrode instrument 24 are rotatably mounted about their longitudinal axes. The electrode instrument 24 has an electrode 30 at its distal end, which is designed as a cutting loop and can be used to remove tissue by electrosurgical ablation. A high-frequency electrical voltage is applied to the electrode 30 to cut the tissue.

[0042] The resectoscope 26 shown has a passive transport mechanism in which the carriage 56 is moved distally against the distal, first handle 52 by relative movement of the handle parts 50 and 52, which are arranged proximally to the resectoscope shaft 14, against a spring force applied by a spring bridge 54. During the distal movement of the carriage 56 against the handle 52, the electrode instrument 24 is forcibly moved distally in a manner not shown. When the handle parts 50 and 52 are released, the spring force generated by the spring bridge 54 forces the carriage 56 back into its rest position, thereby pulling the electrode instrument 24 proximally. During the return movement of the carriage 56, an electrosurgical procedure can be performed passively with the electrode instrument 24 without manual force from the surgeon.

[0043] In contrast to the insulating insert 10 according to the invention, the insulating insert 10 of this conventional resectoscope 26 is not detachably connected to the resectoscope shaft 14, but is permanently fixed to the resectoscope shaft 14 by an adhesive bond (not shown here). Furthermore, the insulating insert 10 does not include any fastening means 18.

[0044] Fig. 2 Figure 1 shows a schematic, lateral sectional view of an alternative resectoscope 26 from the prior art in which the insulating insert 10 is arranged on the sheathing tube 36. Fig. 4 Figure 1 shows a schematic, lateral sectional view of the distal end region of this known resectoscope 26. By attaching the insulating insert 10 to the sheath 36, it is possible to design the resectoscope shaft 14 in an ultra-thin style. Furthermore, the resectoscope 26 essentially corresponds to the one described in the Fig. 1 and 3 resectoscope 26 shown. Also in the one in Fig. 2 and4 In the resectoscope 26 shown, the insulating insert 10 and the resectoscope shaft 14 are connected to each other by a permanent bond.

[0045] In contrast to this usual permanent connection between insulating insert 10 and resectoscope shaft 14, the Figs. 5 to 8 Schematic, lateral sectional views of the distal end region 12 of various resectoscopes 26 according to the invention, in which the connection between the insulating insert 10 and the resectoscope shaft 14 is detachably designed. Apart from the differences according to the invention described below, the resectoscopes 26 shown are essentially the same as those described in the Figs. 1 to 4 26 resectoscopes shown.

[0046] Fig. 5Figure 1 shows an embodiment comprising an insulating insert with radially outwardly arranged fastening means 18. The fastening means 18 are formed as cone-shaped extrusions on the outside of the wall 20 of the insulating insert, i.e., as thickenings 19 of the wall 20. The insulating insert 10 here has more than one fastening means 18, namely at least two, preferably three, which are arranged uniformly along a circumference of the insulating insert 10 in a knob-like fashion. It is also conceivable to arrange a single fastening means as a circumferential bead on the insulating insert 10 instead. In the embodiment shown here, the inner tube 38 has two or more contact elements 21 with a distal contact surface that can be brought into contact with the proximal end of the insulating insert 10, thus preventing the insulating insert 10 from being displaced in the proximal direction.

[0047] Fig. 6Figure 1 shows an insulating insert 10, the wall 20 of which has a conical shape on its outer surface in the proximal end region of the insulating insert 10. In other words, the diameter of the insulating insert 10 is larger at its proximal end than at the distal end of its hollow section 16. It can be seen that the insulating insert 10 is arranged between the outer tube 38 and the inner tube 36, and that a narrowing of the outer tube 36 at its distal end prevents the conically shaped insulating insert 10 from slipping in a distal direction.

[0048] Fig. 7 shows an embodiment in which the resectoscope 26 is made of Fig. 6The insulating insert 10 and the electrode instrument 24 are connected by means of a connection. The electrode instrument 24 is axially displaceably connected to the insulating insert 10 by means of one or more connecting elements 32. Each of the preferably two connecting elements 32 is hollow cylindrical, the longitudinal axis of which extends parallel to the longitudinal axis of the resectoscope shaft 14, and a fork tube 34 of the electrode instrument 24 is axially displaceably guided inside the hollow cylinder.

[0049] Fig. 8 shows an embodiment in which the resectoscope 26 is made of Fig. 7The insulating insert 10 is supplemented by an additional, detachable connection between the insulating insert 10 and the resectoscope shaft 14. It is understood that, within the scope of the invention, it is also possible to dispense with the conical shape of the insulating insert 10 and / or the connecting element 32 in favor of this additional detachable connection. Here, the insulating insert 10 has a locking element 22 to create this additional detachable connection. As can be seen in the magnification shown in Figure B, the locking element 22 in this case is an elongated partial section of the inner wall of the insulating insert 10, connected to the inner wall of the insulating insert 10. This partial section is angled distally and inwardly from the inner wall at a shallow angle. The adjacent outer wall of the inner tube 38 has a corresponding engagement opening 42.If the insulating insert 10 is pushed into the position shown over the distal end region of the inner tube 38, the partial cutout engages with the engagement opening 42. By applying a corresponding pulling force, the insulating insert 10 can be released again and the partial cutout can be broken off.

[0050] Fig. 9 shows how Fig. 8 B,An enlarged section of a resectoscope according to the invention. The insulating insert 10 has a locking element 22 for creating a detachable connection. The locking element 22 is an elongated partial section of the inner wall of the insulating insert 10, connected to the inner wall of the insulating insert 10. The partial section comprises a proximal section angled distally inward at a shallow angle from the inner wall, a distal section that runs substantially parallel to the longitudinal axis of the resectoscope 26, and a distal section that is angled distally outward. The adjacent outer wall of the inner tube 38 has a corresponding engagement opening 42. When the insulating insert 10 is pushed into the position shown over the distal end region of the inner tube 38, the partial section engages with the engagement opening 42.By applying a corresponding pulling force, the insulating insert 10 can be released again without breaking off the partial cutout. This is ensured in particular by the fact that the locking element 22 has a surface that slopes obliquely towards the proximal-inward direction in its distal end region.

[0051] Although the present invention has been described in detail with reference to the exemplary embodiments, it is obvious to the person skilled in the art that the invention is not limited to these exemplary embodiments, but rather that modifications are possible in such a way that individual features can be omitted or different combinations of the individual features presented can be realized, provided that the scope of protection of the attached claims is not left behind. Reference symbol list 10 Insulating insert 48 handle 12 End area 50 handle part 14 Resectoscope shaft 52 handle part 16 hollow section 54 Spring bridge 17 cavity 56 Sleds 18 Fasteners 19 thickening 20 Wall 21 Plant elements 22 Latching element 24 Electrode instrument 26 Resectoscope 28 shaft section 30 electrode 32 Connecting element 34 Fork tube 36 sheathing tube 38 Inner tube 40 optics 42 Access opening 46 retaining element

Claims

1. An electrically insulating insert (10) for detachable connection to the distal end region (12) of a resectoscope shaft (14), wherein the insulating insert (10) has a hollow portion (16) with an elongate cavity (17) for the passage of pass-through instruments and fastening means (18) for detachable connection to the resectoscope shaft (14), wherein the fastening means (18) comprises or consists of a radial thickening (19) of the insulating insert (10) in the hollow portion (16) thereof and the fastening means (18) comprise or consist of a part of a bayonet, screw, snap, clamp, or locking connection, wherein the radial thickening (19) consists in a larger outer diameter of the insulating insert (10) relative to the outer diameter at the distal end of the hollow portion (16), and in a larger diameter of the wall (20) of the insulating insert (10) relative to the diameter of the wall (20) at the distal end of the hollow portion (16), characterized in that a plurality of protrusions are formed on an inner wall of the insulating insert (10), said protrusions being formed so as to run radially along a circumference on the inner wall.

2. The insulating insert (10) claimed in claim 1, characterized in that the fastening means (18) comprises a protruding locking element (22) that is arranged on the fastening side of the hollow portion (16).

3. The insulating insert (10) as claimed in any one of the preceding claims, characterized in that the fastening side of the hollow portion (16) is the outer wall thereof.

4. The insulating insert (10) as claimed in any one of the preceding claims, characterized in that the insulating insert (10) is made of plastic.

5. The insulating insert (10) as set forth in claim 4, characterized in that the plastic is a thermostable plastic.

6. An electrode instrument (24) for use in a resectoscope (26), the electrode instrument (24) having a shaft portion (28) and, at its distal end, an electrode (30) to which high-frequency current can be applied, characterized in that the electrode instrument (24) is connected to an insulating insert (10) as claimed in any one of the preceding claims and the electrode instrument (24) and the insulating insert (10) can be displaced axially relative to one another.

7. The electrode instrument (24) as claimed in claim 6, characterized in that the insulating insert (10) has one or more, preferably two connecting elements (32), in each of which a fork tube (34) of the electrode instrument (24) is supported in an axially displaceable manner.

8. A resectoscope (26) for endoscopic surgery with a tubular resectoscope shaft (14) that comprises an elongate cladding tube (36) and an inner tube (38) that is arranged in the cladding tube, as well as rod-shaped optics (40), characterized in that the resectoscope (26) has a) an insulating insert (10) as claimed in any one of claims 1 to 5 and an electrode instrument (24) with a shaft portion (28) and with an electrode (30) to which high-frequency current can be applied at its distal end; or b) an electrode instrument (24) as claimed in any one of claims 6 to 7.

9. The resectoscope (26) as claimed in claim 8, characterized in that the wall (20) of the insulating insert (10) is arranged in its proximal end region between the cladding tube (36) and the inner tube (38) running inside the cladding tube.

10. The resectoscope (26) as claimed in any one of claims 8 to 9, characterized in that the insulating insert (10) is detachably connected to the distal end region of the cladding tube (36) or of the inner tube (38), and that the cladding tube (36) or the inner tube (38) has an engagement opening (42) for a locking element (22) of the insulating insert (10) in order to form the detachable connection.