Microinvasive medical instrument

Abstract

Medical instrument (10) comprising: a gripping tool (50) for grasping tissue; a shaft (20) to the distal end (24) of which the gripping tool is attached; a cutting edge (67) which is movable in the closed gripping tool (50) in order to cut tissue grasped by means of the gripping tool (50); a transmission device (30) for transmitting at least either a force or a movement to the cutting edge (67), wherein the cutting edge (67) lies in a plane which contains the longitudinal axis of the gripping tool (50), characterized in that the transmission device (30) is arranged at least partially outside the shaft (20) and the transmission device (30) has a tubular section (40) which surrounds the shaft (20).

Description

The present invention relates to a microinvasive medical instrument or a medical instrument for microinvasive procedures. In particular, the present invention relates to a medical instrument with a gripping tool at the distal end of a shaft and a cutting edge that is movable within the closed gripping tool in order to cut tissue grasped by the gripping tool. For medical instruments used in minimally invasive medical procedures, multifunctionality is particularly desirable to avoid the need for multiple changes or replacements of the instrument during a procedure. For example, medical instruments are known (among others from DE 10 2012 007 652 A1, EP 2 653 123 A1, US 2013 / 0310865 A1 and US2003 / 0199869A1) that allow a vessel to be grasped, squeezed, closed, and cut in immediate succession. The medical instrument comprises a gripping tool with two electrically insulated jaws and a blade movable within the closed gripping tool. For example, a blood vessel to be cut can be squeezed using the gripping tool, electrosurgically closed by applying a high-frequency alternating voltage, or...The wound is sealed by electrocautery and then cut open with a knife. Especially with reusable medical instruments, maximum disassembly is generally desirable to simplify cleaning between uses. For example, a medical instrument described in the aforementioned documents has a deep groove in the pull rod, which transmits force to the movable arm, and in which the blade is positioned. When assembling the medical instrument, the blade is inserted proximal to the grasping tool into the groove in the pull rod and then connected to the distal end of a push tube by means of a swivel joint. The push tube and the pull rod, which is arranged coaxially within the push tube, are then inserted distally into a shaft, the distal end of which is connected to the grasping tool. To cut tissue, the blade is advanced distally through the joint of the grasping tool by means of the push tube, within the closed grasping tool. To be able to cut through even a thick layer of tissue, such as a thick-walled vessel, the knife should have the widest possible cutting edge. However, the arrangement of the knife within the gripping tool imposes design limitations on widening the cutting edge. One object of the present invention is to create an improved medical instrument, in particular a medical instrument that is easy to disassemble and reassemble with the lowest possible risk of injury to medical personnel, and that is capable of cutting through the thickest possible layer of tissue. This task is solved by the subject matter of the independent claims. Further training opportunities are listed in the dependent requirements. Embodiments of the present design are based on the idea of ​​arranging a transmission device for transferring force and movement to a cutting edge at least partially outside the shaft of a medical instrument. This can enable a particularly wide design of the cutting edge (especially in a slot in the gripping tool), a simpler and more robust design of the gripping tool's joint, and / or particularly quick, easy, and safe disassembly and assembly of the medical instrument. [1] A medical instrument comprises a gripping tool for grasping tissue, a shaft to the distal end of which the gripping tool is attached or attachable, a cutting edge which is movable within the closed gripping tool in order to cut tissue grasped by means of the gripping tool, and a transmission device for transmitting at least either a force or a torque or a movement to the cutting edge, wherein the transmission device is arranged at least partially outside the shaft. The medical instrument is, in particular, a microinvasive medical instrument or a medical instrument for use in microinvasive surgical procedures or other microinvasive interventions. The medical instrument is specifically designed as a reusable medical instrument that, after use, can be at least partially disassembled and reassembled without damage in order to facilitate cleaning between uses. The gripping tool has, in particular, several branches, at least one of which is movable for gripping fabric, in particular pivotable about an axis. The shaft can be rigid at least in sections and / or elastic or plastically deformable at least in sections. The shaft can have one or more straight sections and / or one or more curved or bendable sections. The shaft can be permanently, i.e., not detachably without damage, connected to the gripping tool. Alternatively, the shaft can be detachably connected to the gripping tool without damage, for example, by means of a locking connection (often also referred to as a bayonet coupling). A proximal end of the shaft can be connected to, or connectable to, a handling device. The cutting edge is movable, in particular, in a direction parallel to the longitudinal axis of the fully or maximally closed gripping tool. The longitudinal axis of the fully closed gripping tool is defined, in particular, by the centroids of the surfaces bounded by the outer contours of the cross-sections of the fully closed gripping tool. If significant outer surface areas of the gripping tool in the fully closed state essentially have the shape of sections of a cylindrical surface, the longitudinal axis of the fully closed gripping tool is the axis of rotational symmetry of this cylindrical surface. Alternatively, the longitudinal axis of the fully closed gripping tool is the axis of symmetry of the smallest cylindrical surface circumscribing the fully closed gripping tool. The cutting edge does not extend parallel to the longitudinal axis of the gripping tool. For example, the cutting edge extends orthogonally to the longitudinal axis of the gripping tool or forms an angle with the longitudinal axis of the gripping tool in the range of 20 to 90 degrees, or in the range of 30 to 80 degrees, or in the range of 40 to 70 degrees, or in the range of 60 to 90 degrees. The cutting edge can be straight or curved. The cutting edge lies, in particular, in a plane that contains the longitudinal axis of the gripping tool. The transmission device extends, in particular, from the proximal end of the shaft (for example, from a handling device located there) to or near a knife that encompasses the cutting edge. The transmission device is, in particular, arranged entirely outside the shaft. Positioning the transmission device at least partially outside the shaft allows for a more compact design, particularly a smaller shaft cross-section. Furthermore, positioning the transmission device outside the shaft eliminates the need for the transmission device or a blade to pass through a joint in the gripping tool. A gripping tool joint through which neither a transmission device nor a blade needs to pass can be simpler, more robust, and / or have a smaller cross-section. The transmission device positioned outside the shaft can also allow for a particularly wide cutting edge, ensuring that even thick layers of fabric can be reliably cut completely. Furthermore, arranging the transmission device outside the shaft can simplify the disassembly and reassembly of the medical instrument, particularly if the cutting edge is directly or indirectly and permanently connected to the distal end of the transmission device, i.e., without the use of a mechanical coupling device. In this case, the transmission device and the cutting edge can, in particular, be slipped over or attached to the medical instrument together from the distal end. [2] In a medical instrument such as the one described here, the transmission device has in particular a tubular section that surrounds the shaft. The tubular section, in terms of its arrangement, corresponds to an outer shaft, which, however, does not hold the grasping tool or its joint at the distal end of the medical instrument, but is movable relative to it in order to move the cutting edge. Insofar as the tubular section of the transmission device is considered the outer shaft, the shaft to whose distal end the grasping tool is attached or can be attached can be referred to as the inner shaft. The tubular section of the transmission device can tubularly enclose the entire shaft, or substantially the entire shaft, or a section of the shaft, so that the shaft is arranged in the tubular section of the transmission device over its entire length, or substantially its entire length, or only partially. [3] In a medical instrument such as described here, the grasping tool in particular has a branch with a distally open slot in which the cutting edge can be moved between a proximal rest position and a distal position near the distal end of the grasping tool. The proximal resting position of the cutting edge is located particularly near a joint of the gripping tool. The distal position of the cutting edge is located particularly near the distal ends of the branches. If the gripping tool has two branches, each branch may have a distally open slot. The arrangement of the cutting edge in a distally open slot in one or both branches of the gripping tool can allow for a particularly large cutting edge width. Specifically, one or both ends of the cutting edge can lie at the edge of the cross-section of the closed gripping tool. Therefore, if both branches each have a distally open slot, the cutting edge can have the greatest width permitted by the cross-section of the closed gripping tool. In particular, the width of the cutting edge, measured in the direction orthogonal to the longitudinal axis of the gripping tool, can correspond to the diameter of the cross-section of the closed gripping tool. This can enable particularly safe cutting, even of very thick tissue layers. [4] A medical instrument as described herein comprises, in particular, a knife having a cutting edge, wherein the knife is permanently and non-destructively mechanically connected to a distal end of the transmission device. The knife may be rigidly or articulatedly permanently and non-destructively mechanically connected to the distal end of the transmission device. A permanent and non-destructively detachable mechanical connection of the knife to the distal end of the transmission device exists, for example, if there is no coupling, locking, latching, or other detachable connection. Separation of the knife from the transmission device is therefore only possible by breaking, tearing, cutting, milling, sawing, or other destructive means. [5] In a medical instrument such as described here, the knife is mechanically rigidly or elastically connected to a distal end of the transmission device. The knife can be connected to the distal end of the transmission device, for example, by a solid body joint, but not by any other type of joint. A permanent and non-destructive mechanical connection between the blade and the distal end of the transmission device can enable a particularly simple and mechanically robust design. The blade and the transmission device form a single unit, which simplifies handling, especially during disassembly, cleaning, and reassembly of the medical instrument. These advantages are particularly pronounced with a rigid or elastic, but in any case jointless, connection between the blade and the transmission device. [6] In a medical instrument such as described here, the transmission device includes in particular a tongue-shaped extension on the tubular section, wherein the knife is mechanically rigidly connected to the tongue-shaped extension. The tongue-shaped extension is provided, in particular, at the distal end of the tubular section. The tongue-shaped extension is, in particular, elastic or, under the forces and moments occurring during the intended use, rigid or not significantly or only insignificantly deformable. The arrangement of the knife on a tongue-shaped extension can allow movement of the cutting edge over a large area without collision of the transmission device with the tissue to be cut. [7] In a medical instrument such as the one described here, in particular both ends of the knife are connected to the distal end of the transmission device. Connecting both ends of the knife to the distal end of the transmission device can provide a particularly rigid and mechanically robust connection between the knife and the distal end of the transmission device. [8] In a medical instrument such as described here, in particular a first end of the knife is mechanically rigidly connected to a first tongue-shaped extension of the transmission device and a second end of the knife is mechanically rigidly connected to a second tongue-shaped extension of the transmission device. The tongue-shaped extensions are provided, in particular, at the distal edge of a tubular section of the transmission device. The arrangement of the knife between two distal ends of tongue-shaped extensions of the transmission device allows movement of the knife along a particularly long distance without collision of the transmission device with tissue held by the grasping tool. [9] In a medical instrument such as the one described here, in particular only one end of the cutting edge is connected to the distal end of the transmission device.

[10] In a medical instrument such as described here, the transmission device is designed to be particularly elastic in the region of its distal end in order to allow elastic deflection of the cutting edge from its intended working position to a mounting position. In particular, a tongue-shaped extension on the tubular section of the transmission device is elastically deformable to move a knife located at the distal end of the tongue-shaped extension, with its cutting edge in a direction essentially orthogonal to the longitudinal axis of the closed gripping tool, away from its working position. The knife can be moved, in particular, in a combined translational and pivoting motion up to a mounting position outside the cross-section of the gripping tool. The mounting position of the knife lies outside the cross-section of the gripping tool, in particular, in that the knife, in the mounting position, no longer engages in a slot in the gripping tool or in one or more branches of the gripping tool where its working position is located. Attaching only one end of the cutting edge to the distal end of the transmission device, and in particular allowing the cutting edge to be elastically deflected from its working position into a mounting position, can enable the unit consisting of the transmission device and the cutting edge to be mounted from the proximal side.

[11] A medical instrument as described herein further comprises in particular a further cutting edge which is arranged parallel to the cutting edge, wherein the transmission device is connected to the cutting edge and to the further cutting edge in such a way that at least either the cutting edge or the further cutting edge can be deflected from its intended working position relative to the tubular section of the transmission device into a mounting position. In particular, each of the two cutting edges is connected to a distal end of an associated tongue-shaped extension of the transmission device, wherein in particular both tongue-shaped extensions are elastically deformable.

[12] In a medical instrument such as described here, the gripping tool in particular has a groove which is formed at least partially by the distally open slot in the branch, wherein the cutting edge is movable in the groove. Brief description of the characters The embodiments are explained in more detail below with reference to the accompanying figures. These show: Fig. 1 a schematic representation of a medical instrument; Fig. 2 another schematic representation of the medical instrument from Fig. 1; Fig. 3 another schematic representation of the medical instrument from Figs. 1 and 2; Fig. 4 another schematic representation of the medical instrument from Figs. 1, 2 to 3; Fig. 5 a schematic axonometric representation of a distal end of a medical instrument; Fig. 6 another schematic axonometric representation of the distal end of the medical instrument from Fig. 5; Fig. 7 a schematic axonometric representation of part of another medical instrument; Fig. 8 a schematic axonometric representation of part of another medical instrument. Description of the embodiments Fig. 1 shows a schematic representation of a medical instrument 10 with a proximal end 12 and a distal end 14. The proximal end 12 of the medical instrument 10 can comprise or be formed by a handling device 16, as shown in Fig. 1. Alternatively, the proximal end 12 of the medical instrument 10 can be provided for coupling with a handling device 16. The handling device 16 comprises a first actuating device 17, for example in the form of a grip eye provided for the thumb of a person's hand, which is slidable or pivotable between two extreme positions. Furthermore, the handling device 16 comprises a second actuating device 18, for example in the form of a push button or a lever, which is slidable or pivotable between two extreme positions by the index finger. The medical instrument 10 further comprises a shaft 20, which is only partially visible in Fig. 1. The shaft 20 extends from the handling device 16 at the proximal end 12 of the medical instrument 10 to its distal end 24. The shaft 20 can be curved or, as shown in Fig. 1, straight. The shaft 20 can be rigid or elastic and / or plastically deformable. The shaft 20 has a longitudinal axis 28, which is defined by the centroids of the surfaces bounded by the outer contours of the cross-sections of the shaft 20. If the shaft 20 has a straight circular cylindrical shape, the longitudinal axis 28 of the shaft 20 is the axis of rotational symmetry of the outer surface of the shaft 20. A gripping tool 50 is provided at the distal end 14 of the medical instrument 10. The gripping tool 50 has a joint 51 and a first branch 52 that are rigidly connected to the distal end 24 of the shaft 20. The joint 51 and the first branch 52 of the gripping tool 50 can be permanently and non-destructively connected to the distal end 24 of the shaft 20. Alternatively, the joint 51 and the first branch 52 of the gripping tool 50 can be connected to the distal end 24 of the shaft 20 via a non-destructively detachable mechanical connection, for example, a swivel joint. The gripping tool 50 further comprises a second branch 54, which is pivotably connected to the first branch 52 via the joint 51. The joint 51 defines a pivot axis 56 orthogonal to the longitudinal axis 28 of the shaft 20 and orthogonal to the plane of Fig. 1, about which the second branch 54 can pivot. In Fig. 1, the gripping tool 50 is shown in an open position or configuration in which the branches 52 and 54 are spaced apart from each other or enclose an angle that is significantly greater than zero. In a fully closed state of the gripping tool 50 (not shown in Fig. 1), it has a longitudinal axis 58, which is defined in particular by the centroids of the surfaces bounded by the outer contours of the cross-sections of the fully closed gripping tool. If significant outer surface areas of the gripping tool 50 in the fully closed state essentially have the shape of sections of a cylindrical surface, the longitudinal axis 58 of the fully closed gripping tool 50 is the axis of rotational symmetry of this cylindrical surface. In the example shown in Fig. 1, the longitudinal axis 58 of the fully closed gripping tool 50 corresponds to the longitudinal axis 28 of the shaft 20. In the case of a curved or flexible shaft 20, the longitudinal axis 58 of the fully closed gripping tool 50 is, in particular, parallel to the longitudinal axis of the distal end of the shaft 20. The first actuating device 17 is mechanically coupled to the second, pivotable arm 54 of the gripping tool 50 by means of a pull rod or other transmission device arranged inside the shaft 20 and therefore not visible or shown in Fig. 1. Therefore, a movement of the first actuating device 17 on the handling device 16 is accompanied by a pivoting movement of the second arm 54 of the gripping tool 50 about the pivot axis 56 defined by the joint 51. In Fig. 1, the first actuating device 17 is shown in a proximal position and the second arm 54 in a corresponding position spaced (by an angle) from the first arm 52. The medical instrument 10 further comprises a transmission device 30 with a proximal end 32 and a distal end 34. The proximal end 32 is arranged in the handling device 16, is therefore not visible, and is indicated in Fig. 1 only by a dashed outline. The transmission device 30 comprises a tubular section 40 that surrounds the shaft 20. A longitudinal axis 38 of the transmission device 30, in particular of the tubular section 40 of the transmission device 30, is defined by the centroids of the surfaces bounded by the outer contours of the cross-sections of the transmission device 30. Insofar as the transmission device 30, in particular the tubular section 40 of the transmission device 30, has a circular cylindrical shape, the longitudinal axis 38 of the transmission device 30 is the axis of rotational symmetry of the transmission device 30. The longitudinal axis 28 of the shaft 20 and the longitudinal axis 38 of the transmission device 30 are, in particular, parallel to each other. In the example shown, the longitudinal axis 28 of the shaft 20 and the longitudinal axis 38 of the transmission device 30 coincide. The outer surface of the shaft 20 and the inner surface of the tubular section 40 of the transmission device 30 are designed such that the tubular section 40 of the transmission device 30 is guided on the shaft 20 with minimal play and friction. The inner surface of the tubular section 40 of the transmission device 30 and the outer surface of the shaft 20 are geometrically similar. For example, both the outer surface of the shaft 20 and the inner surface of the tubular section 40 of the transmission device 30 have the shape of a cylindrical surface. In the illustrated example, the tubular section 40 of the transmission device 30 largely encloses the shaft 20. The tubular section 40 of the transmission device 30 extends, in particular, from the handling device 16 at the proximal end 12 of the medical instrument 10 to near the distal end 24 of the shaft 20. At its distal edge, the tubular section 40 of the transmission device 30 transitions into two tongue-shaped extensions 42, 44, which form the distal end 34 of the transmission device 30. The tongue-shaped extensions 42, 44 on the tubular section 40 of the transmission device 30 each have, in particular, the shape of a narrow, elongated rectangle or a narrow, elongated, and essentially rectangular section of a lateral surface of a circular cylinder. The medical instrument 10 further comprises a knife 60. The knife 60 is arranged in slots, which are not visible in Fig. 1, in the branches 52, 54 of the gripping tool 50 and is therefore largely hidden by the branches 52, 54 in the illustration in Fig. 1 and only indicated by dashed contours. A first end 62 of the knife 60 is rigidly mechanically connected to the distal end of the first tongue-shaped extension 42 on the tubular section 40 of the transmission direction 30. A second end 64 of the knife 60 is rigidly mechanically connected to the distal end of the second tongue-shaped extension 44 on the tubular section 40 of the transmission device 30. In particular, the ends 62, 64 of the knife 60 are joined to the distal ends of the tongue-shaped extensions 42, 44 by welding, brazing, or other means. The knife 60 has a cutting edge 67 that extends substantially from the first end 62 to the second end 64 of the knife 60. In the illustrated example, the cutting edge 67 is substantially straight, parallel to the plane of Fig. 1 and orthogonal to the longitudinal axis 28 of the shaft 20, to the longitudinal axis 38 of the transmission device 30, and to the longitudinal axis 58 of the fully closed gripping tool 50. The proximal end 32 of the transmission device 30 is coupled to the second actuating device 18 of the handling device 16 (not shown in Fig. 1) such that a manual movement of the second actuating device 18 is accompanied by a displacement of the transmission device 30 and the knife 60 parallel to the longitudinal axis 38 of the transmission device 30. The intended direction of movement of the transmission device 30 is therefore, in the illustrated example, parallel to the longitudinal axis 38 of the transmission device 30. The intended direction of movement of the knife 60 is parallel to the longitudinal axis 58 of the fully closed gripping tool 50, which, in the illustrated example, is parallel to the longitudinal axis 28 of the shaft 20 and parallel to the longitudinal axis 38 of the transmission device 30. In the illustrated example, one or more protective ribs 57 are arranged on the second branch 54 and / or on the first branch 52 of the gripping tool 50. When the gripping tool 50 is open, or when the branches 52 and 54 of the gripping tool are spaced apart from each other, the protective rib(s) are at least partially located in the space between the branches 52 and 54. The protective rib(s) are arranged, in particular, parallel to the blade 60 and / or directly adjacent to the blade 60. Distal edges of the protective ribs 57 are arranged and designed such that, when the gripping tool 50 is open, they lie distal to the cutting edge 67 of the blade 60 in its proximal rest position shown in Fig. 1. This prevents the protective rib(s) 57 from coming into contact with the cutting edge 67 of the blade 60 in its rest position. Fig. 2 shows another schematic representation of the medical instrument from Fig. 1. The representation in Fig. 2 is largely similar to that in Fig. 1. The representation in Fig. 2 differs from that in Fig. 1, in particular, in that a different situation or configuration of the medical instrument 10 is shown. In the situation or configuration of the medical instrument 10 shown in Fig. 2, the first actuating device 17 assumes a distal position, and the second branch 54 of the gripping tool 50 assumes a corresponding closed position, directly adjacent to the first branch 52 of the gripping tool 50. Fig. 3 shows a further schematic representation of the medical instrument 10 from Figs. 1 and 2. The plane of Fig. 3 is orthogonal to the planes of Figs. 1 and 2 and parallel to the longitudinal axes 28, 38, 58 of the shaft 20, the transmission device 30, and the fully closed gripping tool 50. The plane of Fig. 3 is also parallel to the pivot axis 56 of the second branch 54 of the gripping tool 50, defined by the joint 51. The configuration or situation shown in Fig. 3 corresponds to that shown in Fig. 2, in which the gripping tool is fully closed, i.e., the second branch 54 rests against the first branch 52 substantially along its entire length. The slots 53, 55 in the branches 52, 54, which were already mentioned but are not visible in Figs. 1 and 2, are visible in Fig. 3. Furthermore, the knife 60 with the cutting edge 67 is visible in the slots 53, 55. The cutting edge 67 extends essentially orthogonally to the plane of Fig. 3. In the example of a medical instrument 10 shown in Figs. 1, 2 to 3, the blade 60 is arranged in its extremely proximal rest position distal to the pivot axis 56 of the second branch 54 defined by the joint 51. This allows the joint 51 to be designed without a cavity, in particular with a continuous shaft, and thus enables simpler manufacturing and greater mechanical stability and robustness. Figures 1 and 2 show that the second tongue-shaped extension 44 is shorter than the first tongue-shaped extension 42 on the tubular section 40 of the transmission device 30. In particular, the distal end of the second tongue-shaped extension 44 on the tubular section 40 is arranged proximal to the pivot axis 56 defined by the joint 51. Figure 1 shows that this positioning of the distal end of the second tongue-shaped extension 44 on the tubular section 40 increases the maximum opening angle or pivot range of the second branch 54 of the gripping tool 50. To connect with the distal end of the second tongue-shaped extension 44 on the tubular section 40, the second end 64 of the knife 60 is extended proximally. Fig. 4 shows a further schematic representation of the medical instrument 10 from Figs. 1, 2 to 3. The style of representation corresponds to that of Fig. 3. In particular, the plane of the drawing in Fig. 4 corresponds to that of Fig. 3. Figure 4 shows a situation or configuration that differs from the configuration shown in Figures 2 and 3, particularly in that the transmission device 30 and, with it, the blade 60 are displaced distally. Specifically, the blade 60 assumes an extremely distal position, with the cutting edge 67 located at the distal end 59 of the gripping tool 50. When the blade 60 moves distally from its resting position shown in Figures 1, 2 to 3, the cutting edge 67 cuts through tissue held and crushed by the gripping tool 50. The transmission device 30 and with it the knife 60 can be moved from their extremely proximal positions shown in Figs. 1, 2 to 3 to their extremely distal positions shown in Fig. 4, in particular by manually actuating the second actuating device 18 on the handling device 16. Specifically, the transmission device 30 and the knife 60 can be moved distally from the position shown in solid lines in Figs. 1 and 2 to the position shown in dashed lines in Figs. 1 and 2 by pressing on the second actuating device 18 and moving it from that position. Fig. 5 shows a schematic axonometric representation of a distal region of another medical instrument, which is similar in some features, properties, and functions to the medical instrument shown in Figs. 1, 2, 3 to 4. The medical instrument 10 is shown in a situation or configuration similar to that shown in Figs. 2 and 3. In sections 52, 54 of a gripping tool 50 at the distal end 14 of the medical instrument 10, distally open slots 53, 55 are provided in which a knife 60 with a cutting edge 67 is arranged. The cutting edge 67 extends substantially orthogonally to the longitudinal axis 58 of the fully closed gripping tool 50. The transmission device 30 has a tubular section 40 that extends to the distal end 34 of the transmission device 30. In particular, the entire transmission device 30 is tubular. A second end 64 of the knife 60, visible in Fig. 5, is permanently and rigidly connected to the distal edge of the transmission device 30, in particular by welding or by other metallurgical bonding. Fig. 6 shows another schematic axonometric representation of the distal region of the medical instrument 10 from Fig. 5. The type of representation, in particular the viewing direction, corresponds essentially to that of Fig. 5. In contrast to Fig. 5, in Fig. 6 the transmission device 30 and the blade 60 are shown separately from the other parts of the medical instrument 10. Fig. 6 thus shows a partially disassembled state of the medical instrument 10. Starting from the partially disassembled state shown in Fig. 6, the tubular transmission device 30 can be slipped over the gripping tool 50 and the shaft 20 from the distal end 14, and the blade 60 can also be inserted from the distal end 59 of the gripping tool 50 into the slots 53, 55 in the jaws 52, 54 to produce the state shown in Fig. 5. In Fig. 6, the joint 51 of the gripping tool 50, which is concealed by the transmission device 30 in Fig. 5, is visible. The shaft 20 of the medical instrument 10 is also visible. Furthermore, the first end 62 of the knife 60, which is not visible in Fig. 5, is visible. Like the second end 64 of the knife 60, it is connected to the distal edge of the tubular transmission device 30 at a diametrically opposite point. Fig. 7 shows a schematic axonometric representation of a transmission device 30 and a blade 60 of another medical instrument, which is similar in some features, properties, and functions to the medical instruments shown in Figs. 1, 2, 3, 4, 5 to 6. In particular, the transmission device 30 and the blade 60 shown in Fig. 7 can replace the transmission devices and blades shown in the medical instruments shown in Figs. 1, 2, 3, 4, 5 to 6. The transmission device 30 shown in Fig. 7 is similar to the transmission device shown in Figs. 1, 2, 3 to 4. In contrast to the medical instrument shown in Figs. 1, 2, 3 to 4, the knife 60 shown in Fig. 7 has an essentially simple rectangular shape. Accordingly, the distal ends of both tongue-shaped extensions 42, 44 of the tubular section 40 of the transmission device 30 lie in a plane or substantially in a plane orthogonal to the longitudinal axis 38 of the transmission device 30. In order to allow a wide opening of the gripping tool 50 or a large pivoting range of the second branch 54 of the gripping tool 50 (see Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5 to Fig. 6), the second branch 54 can have a recess into which, when opening, the distal end of the second tongue-shaped extension 44 on the tubular section 40 of the transmission device 30 dips. Fig. 8 shows a schematic axonometric representation of a transmission device 30 and a blade 60 of another medical instrument, which is similar in some features, properties, and functions to the medical instruments shown in Figs. 1, 2, 3, 4, 5, 6 to 7. The style of representation, in particular the viewing direction, corresponds essentially to that of Figs. 5, 6 to 7. In particular, the transmission device 30 and the blade 60 can replace the transmission devices and blades shown in the medical instruments shown in Figs. 1, 2, 3, 4, 5 to 6. The transmission device 30 shown in Fig. 8 differs from the transmission devices shown in Figs. 1, 2, 3, 4, 5, 6 to 7, in particular in that only a tongue-shaped extension 42 is provided at the distal end of the tubular section 40. Accordingly, the knife 60 is connected to the transmission device 30 only at one end 62 via the tongue-shaped extension 42. The cutting edge 67 of the knife 60 is, in particular, L-shaped, with a section of the cutting edge 67 at the second end 64 of the knife 60 being parallel to the longitudinal axis 38 of the transmission device 30. The tongue-shaped extension 42 can be designed to be elastic due to its geometry and material, in order to allow elastic deformation and thus deflection of the knife 60 from its operating position shown in Fig. 8. If the tongue-shaped extension 42 is sufficiently elastic, the knife 60 can be deflected from the operating position shown in Fig. 8 into a mounting position to such an extent that the knife 60 no longer projects into a distally extending cylinder that fills the interior of the tubular section 40 of the transmission device 30. When the knife 60 is in this mounting position, the transmission device 30 and the knife 60 can be slid from proximally over the shaft 20 (see Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5 to Fig. 6). In this case, the knife 60 only returns to its operating position shown in Fig. 8 when it plunges into the proximal ends of the slots 53, 55 in the branches 52, 54.In this case, the slots 53, 55 do not need to be open distally, unlike as shown in Fig. 3, Fig. 4, Fig. 5 to Fig. 6. Reference sign 10 medical instrument 12 proximal end of the medical instrument 10 14 distal end of the medical instrument 10 16 handling device at the proximal end 12 of the medical instrument 10 17 first actuating device on the handling device 16 18 second actuating device on the handling device 16 20 shaft of the medical instrument 10 24 distal end of the shaft 20 28 longitudinal axis of the shaft 20 30 transmission device of the medical instrument 10, in particular32 Proximal end of the transmission device 30 34 Distal end of the transmission device 30 38 Longitudinal axis of the transmission device 30 40 Tubular section of the transmission device 30 42 First tongue-shaped extension on the tubular section 40 of the transmission device 30 44 Second tongue-shaped extension on the tubular section 40 of the transmission device 30 50 Gripping tool at the distal end 14 of the medical instrument 10 51 Joint on the gripping tool 50 52 First branch of the gripping tool 50 53 Slot in the first branch 52 of the gripping tool 50 54 Second branch of the gripping tool 50 55 Slot in the second branch 54 of the gripping tool 50 56 Pivot axis of the second branch 54 57 Protective rib 58 Longitudinal axis of the fully closed gripping tool 50 59 Distal end of the gripping tool 50 60 Knife 62 first end of the knife 60 64 second end of the knife 60 67 cutting edge on the knife 60.

Claims

Medical instrument (10) comprising: a gripping tool (50) for grasping tissue; a shaft (20) at the distal end (24) of which the gripping tool is attached; a cutting edge (67) which is movable in the closed gripping tool (50) in order to cut tissue grasped by means of the gripping tool (50); a transmission device (30) for transmitting at least either a force or a movement to the cutting edge (67), wherein the cutting edge (67) lies in a plane which contains the longitudinal axis of the gripping tool (50), characterized in that the transmission device (30) is arranged at least partially outside the shaft (20) and the transmission device (30) has a tubular section (40) which surrounds the shaft (20). Medical instrument (10) according to the preceding claim, wherein the gripping tool (50) has a branch (52, 54) with a distally open slot (53, 55) in which the cutting edge (67) is movable between a proximal rest position and a distal position near the distal end (59) of the gripping tool (50). Medical instrument (10) according to the preceding claim, further comprising: a knife (60) having the cutting edge (67), wherein the knife (60) is permanently and non-destructively mechanically connected to a distal end (34) of the transmission device (30). Medical instrument (10) according to the preceding claim, wherein the knife (60) is mechanically rigidly or elastically connected to a distal end (34) of the transmission device (30). Medical instrument (10) according to one of claims 3 and 4, wherein the transmission device (30) comprises a tongue-shaped extension (42, 44) on the tubular section (40), and the knife (60) is mechanically rigidly connected to the tongue-shaped extension (42, 44). Medical instrument (10) according to one of claims 3 to 5, wherein both ends (62, 64) of the knife (60) are connected to the distal end (34) of the transmission device (30). Medical instrument (10) according to the preceding claim, wherein a first end (62) of the knife (60) is mechanically rigidly connected to a first tongue-shaped extension (42) of the transmission device (30) and a second end (64) of the knife (60) is mechanically rigidly connected to a second tongue-shaped extension (44) of the transmission device (30). Medical instrument according to one of claims 1 to 6, wherein only one end (62) of the cutting edge (67) is connected to the distal end (34) of the transmission device (30). Medical instrument according to one of the preceding claims, wherein the transmission device (30) is elastically designed in the region of its distal end (34) to allow elastic deflection of the cutting edge (67) from its intended working position towards a mounting position. Medical instrument (10) according to one of claims 8 and 9, further comprising: a further cutting edge arranged parallel to the cutting edge (67), wherein the transmission device (30) is connected to the cutting edge (67) and to the further cutting edge in such a way that at least either the cutting edge (67) or the further cutting edge can be deflected from its intended working position relative to the tubular section (40) of the transmission device (30) into a mounting position. Medical instrument (10) according to one of the preceding claims, wherein the gripping tool (50) has a groove (53, 55) which is at least partially formed by the distally open slot (53, 55) in the branch (52, 54), and the cutting edge (67) is movable in the groove (53, 55).

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