Inner tube for a surgical cutting instrument, and method

Abstract

The invention relates to a method for producing an inner tube for a surgical cutting instrument comprising: a. an outer tube which has an outer-tube head piece at a distal end of the outer tube; b. which outer-tube head piece has an outer-tube window; wherein c. the inner tube can be rotatably arranged in the outer tube; d. an inner-tube head piece is provided at a distal end of the inner tube; wherein e. at least one cutting edge is formed on the inner-tube head piece, which cutting edge is moved out of the interior of the outer tube through the outer-tube window when the inner tube is rotated and is moved back into the interior of the outer tube through the outer-tube window when the inner tube is rotated further. The method comprises the following steps: f. providing an inner-tube middle piece which has a distal end; g. forming the inner-tube head piece at the distal end of the inner-tube middle piece by means of an additive manufacturing process in order to obtain the inner tube.

Description

[0001] Inner tube for a surgical cutting instrument and method for its manufacture

[0002] The invention relates to the field of surgical cutting instruments. It particularly concerns an inner tube for a surgical cutting instrument and a method for its manufacture according to the independent patent claims.

[0003] In closed or endoscopic surgery, surgical cutting instruments are used, among other things, which comprise two tubes with parallel longitudinal axes that are pushed into one another. At one distal end, a so-called "cutting head" is located and at the other end, a coupling for connection to, for example, a drive turbine. End pieces at the distal end can be open or closed at the front and also have forward-facing lateral openings through which a rinsing fluid can be supplied and, during a corresponding surgical procedure, severed tissue can be removed, in particular suctioned off, especially together with the rinsing fluid. These tubes generally have a small diameter d in the range of a few millimeters, in particular 2.5 mm < d < 10 mm, and a comparatively long length, in particular in the range of 15 cm < / < 30 cm.

[0004] Exemplary surgical cutting instruments of the type mentioned are described in EP 1773215 A1, the contents of which are hereby incorporated by reference in their entirety.

[0005] The cutting instruments mentioned comprise an inner tube and an outer tube as two tubes pushed into one another, wherein the inner tube is rotatable about its longitudinal axis and / or relative to the outer tube, in particular by means of the drive turbine.

[0006] At a distal end of the outer tube, an outer tube head piece is provided, which is also referred to as an outer head piece (in particular in EP 1773215 A1). At a distal end of the inner tube, an inner tube head piece is provided, which is also referred to as an inner head piece (in particular in EP 1773215 A1). The outer tube head piece and / or inner tube head piece can each have one or more cutting edges, in particular in the region of their respective distal ends, which slide and / or shear past each other when the inner tube rotates about its longitudinal axis and / or relative to the outer tube, and can thus sever tissue, bones and / or other body parts, in particular relatively soft tissue such as connective tissue, muscles, cartilage or tendons, similar to scissors.To separate such tissue, the interaction of two cutting edges is generally required, a first of which is formed on the outer tube, in particular on the outer tube headpiece, and a second of which is formed on the inner tube, in particular on the inner tube headpiece. A cutting edge formed on the inner tube is also referred to as an inner cutting edge; a cutting edge formed on the outer tube is referred to as an outer cutting edge.

[0007] To ensure sufficient mechanical stability of the inner tube, the inner tube, in particular the inner tube headpiece, is generally at least partially closed at its distal end. The cutting edges are generally provided at one or more so-called inner openings, which are also referred to below as cutting windows. A cutting window can be formed by an at least substantially lateral opening in the inner tube, wherein the cutting edges of a cutting window are formed in particular in a region of the remaining material of the inner tube, in particular of the inner tube headpiece, surrounding the cutting window, which delimit the cutting window in a circumferential direction of the inner tube.

[0008] Through an opening provided in a distal region, particularly at the distal end, of the outer tube, which is also referred to as an outer tube window, the inner cutting edge can be moved out of the interior of the outer tube through the outer tube window by rotating the inner tube and, upon further rotation, back into the interior of the outer tube through the outer tube window. The inner cutting edge can slide or shear past the outer cutting edge, preferably formed at the edge of the outer tube window, thereby severing tissue. The outer tube window can be directed laterally forward, in particular.

[0009] Cutting windows and / or outer pipe windows are generally formed by means of material removal, in particular by means of an erosion process, in particular by means of wire erosion, in or from a precursor of the inner pipe, in particular of the inner pipe head piece, in particular simultaneously with any cutting edges that may be provided.

[0010] However, such EDM processes impose limitations on the geometries that can be achieved. This particularly applies to cutting windows provided or to be provided on the inner tube, where machining on the inside of a wall forming the inner tube is generally necessary to create optimal cutting edges. In wire EDM processes, such limitations arise in particular from the fact that a respective working area of ​​the EDM process must be accessible from two opposite sides in order to be able to guide a straight-line EDM wire to the working point and away from it. The working area of ​​the EDM process can be understood as the shortest distance between the EDM wire and the workpiece. This particularly limits the minimum achievable cutting angles of the inner cutting edges, which, analogous to EP 1773215 A1, can be defined as the angle ß of the inner cutting edge to an outward tangent.In practice, cutting angles of less than 30° cannot be produced, i.e. ß > 30° must apply.

[0011] Although so-called countersinking, drilling, or bar EDM processes allow greater degrees of freedom, since the working area only needs to be accessible from one side, due to the larger cross-section and / or diameter of the EDM electrodes compared to the EDM wire required to achieve sufficient mechanical stability, only larger radii of curvature can be realized, which can be particularly hindering when forming the cutting edges and can result in other restrictions.

[0012] To mitigate the limitations outlined above regarding possible geometries during wire EDM, the inner tube headpiece is often manufactured from a separate precursor or blank in the form of a relatively short tube piece, whereby the EDM wire can be guided through an open, particularly proximal, end of the tube piece. This may be necessary, in particular, for the production of an inner tube headpiece with a single cutting window; however, it entails significant limitations regarding possible cutting window geometries. Additionally and / or alternatively, several cutting windows offset from one another in the circumferential direction, particularly opposite one another, can be provided simultaneously, whereby the EDM wire is guided through two cutting windows at a time.However, such an approach entails considerable limitations with regard to possible cutting window and edge geometries, especially when there is an odd number of cutting windows.

[0013] In addition, the separately manufactured inner tube head piece must then be connected and / or attached to an inner tube center piece, for example, by welding, to create a complete inner tube. However, this can cause several potential problems: First, the inner diameter or cross-section of an inner tube manufactured in this way may be reduced in an area of ​​a resulting welded joint. This can lead to restrictions and / or obstructions in the removal, especially suction, of irrigation fluid, especially if it contains a large amount of tissue.

[0014] Irregularities in the welded joint on one side of the inner tube can also hinder the rotation of the inner tube relative to the outer tube.

[0015] Finally, welding requires an additional work step that complicates, increases the cost, and / or slows down the production of the inner tube.

[0016] For removing harder tissue, such as bone in particular, the inner tube headpiece can also be designed as a milling head in the region of the distal end. A milling head can, in particular, have at least one cutting edge, which can remove material, especially harder material, even without interaction with another cutting edge. Instead of the inner tube described above, a correspondingly designed inner tube with one or more cutting windows can be inserted into an identical or similarly designed outer tube. The rotating milling head then protrudes from the outer tube in the region of the outer tube window and can remove hard tissue in this area in a controlled manner.

[0017] The invention is therefore based on the object of specifying a method for producing a surgical cutting instrument and a surgical cutting instrument obtainable by this method, which avoids the above-mentioned disadvantages.

[0018] Brief description of the invention

[0019] This object is achieved according to the invention by a method for producing an inner tube for a surgical cutting instrument and by a surgical cutting instrument with an inner tube that can be produced by the method according to the independent patent claims.

[0020] A method for producing an inner tube for a surgical cutting instrument, comprising: a. an outer tube with an outer tube headpiece at a distal end of the outer tube; b. said outer tube headpiece having an outer tube window; c. the inner tube being rotatably disposed within the outer tube; d. an inner tube headpiece being provided at a distal end of the inner tube; e. at least one cutting edge being formed on the inner tube headpiece, which cutting edge is moved out of the interior of the outer tube through the outer tube window upon rotation of the inner tube and is moved back into the interior of the outer tube through the outer tube window upon further rotation; said method may comprise the following steps: f. providing an inner tube centerpiece having a distal end; g. forming the inner tube headpiece at the distal end of the inner tube centerpiece using an additive manufacturing process to produce the inner tube.

[0021] A method for producing a surgical cutting instrument comprising: a. an outer tube with an outer tube headpiece at a distal end of the outer tube; b. an inner tube rotatably arranged in the outer tube with an inner tube headpiece at a distal end of the inner tube; wherein c. the outer tube headpiece has an outer tube window; d. at least one cutting edge is formed on the inner tube headpiece, which cutting edge is moved out of an interior of the outer tube through the outer tube window upon rotation of the inner tube and is moved back into the interior of the outer tube through the outer tube window upon further rotation; can comprise the following method steps: e. providing an inner tube middle piece with a distal end; f. forming the inner tube headpiece at the distal end of the inner tube middle piece by means of an additive manufacturing process to obtain the inner tube; g. inserting the inner tube into the outer tube.

[0022] The above-described inventive methods are based on the idea of ​​forming the inner tube head piece at a distal end of an inner tube center piece using an additive manufacturing process, in particular a powder-bed-based additive manufacturing process, in a single operation, in particular directly and / or immediately at said distal end, simultaneously connecting it to the inner tube center piece, and providing all geometric and / or structural features. The inner tube center piece serves, in a sense, as a blank and / or precursor for the inner tube.

[0023] A straight, particularly cylindrical, tube section, particularly with a length between 10 cm and 20 cm, can be selected as the inner tube centerpiece, preferably made of a material suitable and / or approved for surgical applications, especially stainless steel. The inner tube centerpiece can comprise a section designed as a flexible shaft. An inner and / or outer cross-section of the inner tube centerpiece can be homogeneous over its entire length.

[0024] The inner tube centerpiece can be positioned inside a working volume of a device for performing an additive manufacturing process, in particular inside a 3D printing chamber, such that a longitudinal axis of the inner tube centerpiece is aligned at least substantially perpendicularly, i.e., in a vertical direction. Preferably, a plurality of inner tube centerpieces, in particular between 50 and 500 inner tube centerpieces, can be positioned side by side and / or parallel to one another. The inner tube centerpieces can be arranged in two horizontal directions perpendicular to the vertical direction in such a way that they utilize the working volume as effectively as possible.

[0025] The working volume can then be filled with a powder necessary and suitable for carrying out the additive manufacturing process to such an extent that the one or more inner tube center pieces are completely surrounded by the powder, so that in particular the distal end of the inner tube center pieces does not protrude from the powder.

[0026] By means of the additive manufacturing process, an inner tube head piece can then be formed layer by layer on the distal ends of the one or more inner tube center pieces, which in particular can be at least approximately circular, wherein, to increase mechanical stability, a short tubular region can first be formed, which preferably has an identical inner and / or outer cross-section and / or diameter as the one or more inner tube center pieces, and preferably a length of a few millimeters to a few centimeters.

[0027] Adjacent to the short tubular region, which may form a proximal end of the inner tube headpiece, a cutting window region comprising one or more cutting windows can be formed. Several cutting windows can have an identical shape, at least in pairs, and / or be evenly distributed around the cutting window region in a circumferential direction.

[0028] Using the additive manufacturing process, any desired cutting angle can be created for each cutting edge. In particular, an angle ß of the inner cutting edge to an outward tangent of ß < 10° can be achieved, especially ß < 8°, as is common with razor blades, for example.

[0029] The additive manufacturing process makes it possible to provide at least approximately any desired shape, particularly three-dimensional shapes, on both the inside and outside of an inner pipe head piece. This allows for unlimited shaping, in particular the provision of free surfaces and / or free forms on both the inside and outside. Conventional manufacturing processes, such as EDM, do not allow for such unlimited shaping, so that certain shapes cannot be produced using the latter processes. However, even shapes that are fundamentally feasible using EDM may be precluded from practical use, as manufacturing can be too time-consuming and / or resource-intensive – for example, it may require the use of 5-axis machining centers, particularly 5-axis grinding machines, on which only a single inner pipe center piece can be machined at any one time.

[0030] The additive manufacturing process allows, for example, the short tubular section to be designed in such a way that its inner diameter and / or cross-section tapers and widens several times, thereby exhibiting a regular, preferably sinusoidal shape. Surprisingly, such a shape can avoid or prevent obstructions during the removal, especially suction, of irrigation fluid, especially when it carries a large amount of tissue.

[0031] Adjacent to the cutting window area, an inner tube head plate can be formed, which at least partially closes the inner tube head piece at its distal end and / or forms a distal termination of the inner tube head piece. Instead of an inner tube head piece with one or more cutting windows as described above, an inner tube head piece can also be manufactured with a milling head formed at its distal end.

[0032] The powder can be selected so that the one or more inner tube head pieces metallurgically correspond as closely as possible to the one or more inner tube middle pieces, in particular form an alloy with a composition which corresponds as closely as possible to the one or more inner tube middle pieces.

[0033] The roughness and / or fineness of a surface of the inner tube head piece, particularly in the area of ​​the cutting edges, can be determined at least approximately by properties of the powder, such as granularity or average grain diameter. Compared to inner tube head pieces produced by erosion and possibly subsequent grinding, rougher surfaces result, with improved cutting properties and an increased service life of the cutting edges and thus of the corresponding inner tube head piece. Furthermore, it has surprisingly been found that appropriately designed cutting edges avoid or prevent obstructions during the removal, in particular suction, of rinsing fluid, especially when this fluid entails a large amount of tissue, in particular fibrous tissue.This could be due to the fact that the comparatively rough surface of the cutting edge causes cut fibers to be broken and / or shortened to a greater extent.

[0034] In an inner tube according to the invention for a surgical cutting instrument, which can be obtained or produced in particular according to the method described above, an inner tube head piece can be formed in the region of a distal end of the inner tube, wherein a cutting window is provided on the inner tube head piece, which cutting window has a distal and a proximal end, wherein a. two opposite cutting edges are provided between the distal and the proximal end of the cutting window, which in particular delimit the cutting window laterally and / or in the circumferential direction, b. wherein a width of the cutting window initially decreases from the proximal end of the cutting window and / or and increases again towards the distal end.The width of the cutting window can be regarded as a distance, in particular in the circumferential direction, between the two opposite cutting edges at a position with respect to the longitudinal axis, in particular a distance of a first point on a first of the two opposite cutting edges from a second point on a second of the two opposite cutting edges at the same position with respect to a coordinate axis running parallel to the longitudinal direction of the inner tube and / or the inner tube head piece.

[0035] In an inner tube according to the invention for a surgical cutting instrument with an inner tube head piece at a distal end of the inner tube, which can be obtained or produced in particular according to the method described above, an inner tube head piece can be formed in the region of a distal end of the inner tube, wherein one or more cutting windows are provided on the inner tube head piece, each of which has a distal and a proximal end, and a. two opposite cutting edges are provided between the distal and the proximal end, in particular which delimit the cutting window laterally and / or in the circumferential direction, b. wherein the two cutting edges run from the proximal end initially approximately along a helix each with a first direction of rotation, and then along a helix each with a second direction of rotation opposite to the first.

[0036] In an inner tube according to the invention for a surgical cutting instrument with an inner tube head piece at a distal end of the inner tube, which can be obtained or produced in particular according to the method described above, an inner tube head piece can be formed in the region of a distal end of the inner tube, wherein one, in particular exactly one, cutting window is provided on the inner tube head piece, which cutting window has a distal and a proximal end, and a. two opposite cutting edges (2112) are provided between the distal and the proximal end, in particular which delimit the cutting window laterally and / or in the circumferential direction, b. wherein at least one cutting edge (4111, 4112), in particular each of the cutting edges, initially has a convex section 4111a in the direction of the longitudinal axis L and subsequently, in particular adjoining said convex section, has a concave section 4111b, or vice versa.In an inner tube according to the invention for a surgical cutting instrument with an inner tube headpiece at a distal end of the inner tube, which can be obtained or manufactured in particular according to the method described above, the inner tube headpiece can have a. a milling head provided at a distal end, b. a tapered piece remote from the distal end; and c. a connecting piece provided between the milling head and the tapered piece; wherein d. at least one suction window can be provided on the tapered piece, through which fluid can be sucked into the inner tube.

[0037] In an interior of the inner tube, in particular in a channel formed in the inner tube, one or more webs, struts, or bracing can be provided, each of which extends between two regions on an inner side of the inner tube and / or an inner side of a wall forming the inner tube, which are offset from one another at least with respect to a circumferential direction. The two said regions can additionally also be offset from one another with respect to the longitudinal axis and / or a direction parallel to the longitudinal axis. At least one of the regions can be provided between the distal and the proximal end of one or more cutting windows with respect to the longitudinal axis and / or a direction parallel to the longitudinal axis. At least one of the regions can be provided between the proximal end of one or more cutting windows and the proximal end of the inner tube with respect to the longitudinal axis and / or a direction parallel to the longitudinal axis.In particular, a first region may be provided between the distal and the proximal end of one or more cutting windows and a second region longitudinal axis between the proximal end of one or more cutting windows and the proximal end of the inner tube.

[0038] Such webs, struts, or bracings increase the mechanical stability of the inner tube, particularly in an area of ​​the inner tube headpiece, and effectively counteract unwanted bending or twisting, as well as other unwanted deformations of the inner tube, particularly in the area of ​​the inner tube headpiece. This can be particularly important if the inner tube or the inner tube headpiece has a relatively large number of and / or relatively long cutting windows, in particular more than two or even more than three cutting windows and / or cutting window lengths with respect to the longitudinal axis and / or a direction parallel to the longitudinal axis of more than 1 cm, 2 cm, or even more than 3 cm.

[0039] The webs, struts, or bracings can, in particular, be formed integrally with the inner tube and / or the inner tube head piece, and can preferably be created or formed by or within the framework of an additive manufacturing process as described above. Manufacturing by material removal, in particular by an erosion process, is practically impossible, or at least involves prohibitively high costs.

[0040] Advantageous embodiments of the invention are the subject of the dependent claims and / or emerge from the following description in conjunction with the drawings.

[0041] A preferred embodiment of the invention is described below with reference to the accompanying drawings.

[0042] It shows

[0043] Fig. 1 shows a first embodiment of an inner tube according to the invention for a surgical cutting instrument;

[0044] Fig. 2 is a perspective view of a second embodiment of an inner tube according to the invention for a surgical cutting instrument;

[0045] Fig. 3 is a perspective view of a third embodiment of an inner tube according to the invention for a surgical cutting instrument;

[0046] Fig. 4 is a perspective view of an inner tube headpiece according to a fourth embodiment of an inner tube according to the invention for a surgical cutting instrument. Ways of implementing the invention

[0047] Figures 1a-d show a first embodiment of an inner tube according to the invention for a surgical cutting instrument, which is obtainable by means of the method described above.

[0048] Fig. 1a shows a perspective view of the inner tube according to the invention in accordance with the first embodiment; Fig. 1b shows a section along a plane containing a longitudinal axis L of the inner tube; Fig. 1c shows a detail from Fig. 1b; Fig. 1d shows a plan view of the distal end in the direction of the proximal end.

[0049] Three cutting windows 111 are formed on an inner tube headpiece 11, each of which has a proximal end 111a and a distal end 111b. Between the distal end 111b and the proximal end 111a of each cutting window 111, two opposing cutting edges 1111, 1112 are provided, both of which are smooth or without teeth. The cutting edges delimit the cutting window 111 laterally and / or in the circumferential direction U.

[0050] The two cutting edges initially extend toward each other from the proximal end 111a of, in particular, each cutting window 111 and then away from each other. Accordingly, the distance between the two cutting edges initially decreases, only to subsequently increase again. This gives the cutting window 111 a characteristic cushion shape.

[0051] A distal end of the inner tube head piece 11 is formed by an inner tube head plate 112, which is oriented perpendicular to the longitudinal axis L of the inner tube head piece and / or the inner tube. The inner tube head plate 112 is designed as a cutting head plate, with three recesses 1122 provided on a radial edge 1121 of the cutting head plate. Each recess has at least one cutting edge 1123, which is oriented in particular at least approximately perpendicular to the longitudinal axis L and / or in a radial direction of the inner tube head piece 11. With respect to the circumferential direction U, one of the recesses 1122 is provided at an at least substantially identical position to one of the cutting windows 111, in particular a distal end 111b of the respective cutting window 111. The recess 1122 and the respective cutting window thus merge into one another in the region of the distal end of the inner tube head piece 11 or the inner tube.

[0052] Figures 2a-d show a second embodiment of an inner tube according to the invention for a surgical cutting instrument, which is obtainable by means of the method described above.

[0053] Fig. 2a shows a perspective view of the inner tube according to the invention in accordance with the second embodiment; Fig. 2b shows a section along a plane containing a longitudinal axis L of the inner tube; Fig. 2c shows a detail from Fig. 2b; Fig. 2d shows a plan view of the distal end in the direction of the proximal end.

[0054] Three cutting windows 211 are formed on an inner tube headpiece 21, each having a proximal end 211a and a distal end 211b. Between the distal end 211b and the proximal end 211a of each cutting window 211, two opposing cutting edges are provided, of which a first cutting edge 2111 is designed without teeth; a second cutting edge 2112 has straight, flattened teeth with rounded spaces or tooth gaps. The cutting edges delimit the cutting window 211 laterally and / or in the circumferential direction U.

[0055] The two cutting edges extend from the proximal end 211a of, in particular, each cutting window 211, initially approximately along a respective, in particular first, helix with a first direction of rotation, and subsequently along a respective, in particular second, helix with a second direction of rotation opposite to the first. This gives the cutting window 211 a characteristic boomerang, kidney, and / or banana shape.

[0056] A distal end of the inner tube head piece 21 is formed by an inner tube head plate 212, which is oriented perpendicular to the longitudinal axis L of the inner tube head piece and / or the inner tube. The inner tube head plate 212 is designed as a cutting head plate, wherein three recesses 2122 are provided on a radial edge 2121 of the cutting head plate. Each recess has a cutting edge 2123, which is in particular oriented at least approximately perpendicular to the longitudinal axis L. With respect to the circumferential direction U, one of the recesses 2122 is provided at an at least substantially identical position to one of the cutting windows 211, in particular a distal end 211b of the respective cutting window 211. The recess 2122 and the respective cutting window thus merge into one another in the region of the distal end of the inner tube head piece 21 or the inner tube.

[0057] Figures 3a-e show a third embodiment of an inner tube according to the invention for a surgical cutting instrument, which is obtainable by means of the method described above.

[0058] Fig. 3a shows a perspective view of the inner tube according to the invention according to the third embodiment, with an inner tube headpiece 31 at a distal end of the inner tube. This inner tube headpiece has a milling head 311 provided at a distal end, a tapered piece 313 remote from the distal end, and a connecting piece 312 provided between the milling head 311 and the tapered piece 313. Two opposite suction windows 3131 are provided on the tapered piece 313, through which fluid, in particular rinsing fluid, can be sucked into the inner tube.

[0059] The milling head has 8 cutting blades 3111. A cutting edge 3112 is formed along a radially outer edge of each cutting blade. A distal end 3111a of each cutting blade 3111 extends in a first plane, within which the longitudinal axis L runs. A proximal end 3111b of each cutting blade 3111 extends in a second plane, which forms an acute angle with the longitudinal axis L, which is preferably less than 30°, in particular at least approximately 20°.

[0060] In the tapered area, the inner and outer diameters of the inner tube are reduced, in particular to 30% to 75% of the corresponding values ​​of the inner tube centerpiece, in particular to at least approximately 50%. The suction windows 3131 are formed by openings in this area and are thus inclined forward. This enables particularly efficient suction of material removed by the milling head 311.

[0061] Figures 4a) and b) show an inner tube head piece 41, as can be provided in conjunction with a fourth embodiment of an inner tube according to the invention for a surgical cutting instrument, and which inner tube and / or inner tube head piece is obtainable by means of the method described above. Three cutting windows 411 are formed on the inner tube head piece 41, each of which has a proximal end 411a and a distal end 411b. Between the distal end 411b and the proximal end 411a of each cutting window 411, two opposing cutting edges 4111, 4112 are provided, both of which are smooth or without teeth. The cutting edges delimit the cutting window 411 laterally and / or in the circumferential direction U. Between two adjacent cutting windows 411, a wall piece 4113, 4113" or4113", wherein in particular a cutting window 411 is formed between each two of the wall pieces 4113, 4113", 4113", and further in particular a cutting edge 4111 and 4112 is formed on lateral edges of each wall piece 4113, 4113", 4113".

[0062] Each cutting edge 4111 and 4112 initially has a convex section 4111a in the direction of the longitudinal axis L and subsequently, in particular adjacent to said convex section, a concave section 4111b, or vice versa. Such a configuration of the cutting edges 4111, 4112 ensures that, regardless of the direction of rotation of the inner tube, the concave and convex sections of the cutting edge sever tissue, bone, and / or other body components at least approximately simultaneously, thereby enabling more uniform and straighter cutting and / or reducing the risk of jamming or jamming.

[0063] As can be seen from Fig. 4b), a strut 4114 is formed between each two of the wall pieces 4113, 4113", 4113". Such struts increase the mechanical stability of the inner tube, in particular of the inner tube head piece

[0064] Although the invention is illustrated and described in detail by means of the figures and the associated description, this illustration and this detailed description are to be understood as illustrative and exemplary and not necessarily as limiting the invention. In order not to unnecessarily complicate the understanding of the invention, in certain cases well-known features, structures and / or techniques may not be shown or described in detail. It is understood that those skilled in the art can make changes and modifications without departing from the scope of the following claims. In particular, the present invention covers further embodiments with any combination of features that may deviate from the explicitly described combinations of features. The present disclosure also includes embodiments with any combination of features mentioned or shown above or below for various embodiments.It also includes individual features in the figures, even if they are shown there in connection with other features and / or are not mentioned above or below. Furthermore, the alternative embodiments described in the figures and the description, and individual alternatives of their features, may be excluded from the subject matter of the invention or from the disclosed subject matter. The disclosure includes embodiments that exclusively comprise the features described in the claims or in the exemplary embodiments, as well as those that comprise additional other features.

[0065] Furthermore, the term "comprising" and / or derivatives thereof does not exclude other elements or steps. Likewise, the indefinite article "a" or "an" and derivatives thereof does not exclude a plurality. The functions of several features listed in the claims may be performed by a single unit or step. The terms "substantially," "about," "approximately," "approximately," and the like in connection with a property or value, in particular, also precisely define the property or value. The terms "about," "approximately," "approximately," "approximately," etc. in connection with a given numerical value or range may refer to a value or range that lies within 20%, within 10%, within 5%, or within 2% of the given value or range. All reference signs in the claims are not to be understood as limiting the scope of the claims.A statement that a ~ b applies can be understood to mean that |a-ö| / (|a|+|ö|) < 0.2, preferably |a-ö| / (|a|+|ö|) < 0.05, most preferably |a-ö| / (|a|+|ö|) < 0.01, where a and b can represent any variables or quantities defined and / or described anywhere in this document or otherwise known to the person skilled in the art. A statement "few" can in particular mean at least two, preferably at least three and / or a maximum of five. A statement "some" can in particular mean at least three, preferably at least five and / or a maximum of nine.

[0066] The fact that a feature or a property, for example a specific, in particular geometric, shape, is at least approximately formed, provided or present can mean in particular that manufacturing specifications exist which provide a specification according to which the feature is formed accordingly, wherein a deviation from the specification can result within the scope of usual manufacturing tolerances known to the person skilled in the art.

[0067] Features, properties, etc. placed in brackets in the description may be present and / or required, but do not have to be, and are generally to be regarded as optional. Such features can serve to better understand the invention by masking out implicit but unessential aspects. Such features, properties, etc. can be advantageous. The fact that an element or feature is extended in one direction or extends in one direction can in particular mean that dimensions of the element or feature are larger in this direction than in other directions, in particular all other directions, in particular orthogonal directions. The terms “top”, “bottom”, “upper side”, “bottom side” can be understood to mean that a vertical direction V of the kitchen aid shown in the figures runs from top to bottom.

Claims

Patent claims 1. A method for manufacturing an inner tube for a surgical cutting instrument, comprising: a. an outer tube with an outer tube head at a distal end of the outer tube; b. which outer tube head has an outer tube window; wherein c. the inner tube can be rotatably arranged in the outer tube; d. an inner tube head (11, 21, 31) is provided at a distal end of the inner tube; wherein e. at least one cutting edge (1112, 2112, 3112) is formed on the inner tube head, which, when the inner tube is rotated through the outer tube window, is moved out of the interior of the outer tube and, upon further rotation through the outer tube window, is moved back into the interior of the outer tube; wherein the method comprises the following steps: f. providing an inner tube center section with a distal end; g. Forming the inner tube headpiece at the distal end of the inner tube middle section using an additive manufacturing process to obtain the inner tube.

2. A method for manufacturing a surgical cutting instrument comprising: a. an outer tube with an outer tube head at a distal end of the outer tube; b. an inner tube rotatably arranged in the outer tube with an inner tube head (11, 21, 31) at a distal end of the inner tube; wherein c. the outer tube head has an outer tube window; d. at least one cutting edge (1112, 2112, 3112) is formed on the inner tube head, which, when the inner tube is rotated through the outer tube window, is moved out of the interior of the outer tube and, upon further rotation through the outer tube window, is moved back into the interior of the outer tube; wherein the method comprises the following steps: e. providing an inner tube center section with a distal end; f. Forming the inner tube head at the distal end of the inner tube center section by means of an additive manufacturing process to obtain the inner tube; g. Inserting the inner tube into the outer tube. A method according to claim 1 or 2, further comprising: a. Providing an outer tube center section with a distal end; b. Forming the outer tube head at the distal end of the outer tube center section by means of an additive manufacturing process to obtain the outer tube. A method according to claim 1, 2, or 3, wherein a. the inner tube center section and / or the outer tube center section is formed from stainless steel, b. the inner tube head and / or the outer tube head section are formed from stainless steel, in particular by means of selective laser melting (SLM), laser cutting, or direct metal laser sintering (DMLS). A method according to any one of the preceding claims, characterized in that the inner tube and / or outer tube are formed from stainless steel 1.4443.A method according to one of the preceding claims, characterized in that one or more cutting windows, each with one or more cutting edges, are formed on the inner tube head. The inner tube for a surgical cutting instrument has an inner tube head (11) at a distal end of the inner tube, wherein one, in particular exactly one, cutting window (111) is provided on the inner tube head, which has a distal and a proximal end, and a. two opposing cutting edges (1111, 1112) are provided between the distal and the proximal end, which in particular delimit the cutting window laterally and / or circumferentially, b. wherein the width of the cutting window, in particular the circumferential distance between the cutting edges, initially decreases from the proximal end and increases again towards the distal end.

8. Inner tube according to claim 7, wherein at least one or more further cutting windows (111) are provided on the inner tube head piece, each having a distal and a proximal end, wherein a. two opposing cutting edges (1112) are provided between the distal and the proximal ends, which in particular limit the further cutting window(s) laterally and / or circumferentially, b. wherein a width of the further cutting window(s), in particular a distance between the cutting edges in the circumferential direction, initially decreases from the proximal end and increases again towards the distal end.

9. Inner tube for a surgical cutting instrument with an inner tube headpiece (21) at a distal end of the inner tube, wherein a cutting window (211), in particular exactly one, is provided on the inner tube headpiece, which has a distal and a proximal end, and a. between the distal and the proximal end two opposing cutting edges (2111, 2112) are provided, in particular which limit the cutting window laterally and / or circumferentially, b. wherein the two cutting edges first extend from the proximal end at least approximately along a first helix with a first direction of rotation, and then at least along a second helix with a second direction of rotation opposite to the first direction of rotation.

10. Inner tube according to claim 9, wherein at least one or more further cutting windows (211) are provided on the inner tube head piece (21), each having a distal and a proximal end, wherein a. two opposing cutting edges (2111, 2112) are provided between the distal and the proximal end, in particular which limit the cutting window laterally and / or circumferentially, b. wherein the two respective cutting edges first extend from the proximal end approximately along each helix with a first direction of rotation, and then along each helix with a second direction of rotation opposite to the first. Inner tube for a surgical cutting instrument with an inner tube headpiece (41) at a distal end of the inner tube, wherein one or more cutting windows (411) are provided on the inner tube headpiece, each of which has a distal and a proximal end, and a. between the distal and the proximal end two opposing cutting edges (2112) are provided, in particular which limit the cutting window laterally and / or circumferentially, b. wherein at least one cutting edge (4111, 4112), in particular each of the cutting edges in the direction of the longitudinal axis L, first has a convex section (4111a) and subsequently, in particular adjoining said convex section, has a concave section (4111b) or vice versa. Inner tube according to claim 8, 10 or 11, wherein a total of exactly three cutting windows (111, 211, 411) are provided, which are in particular offset from each other by 120° in a circumferential direction.Inner tube according to any one of claims 7 to 12, wherein a first cutting edge of the two opposing cutting edges of a cutting window (111, 211, 411) has teeth and a second cutting edge of the two opposing cutting edges of the corresponding cutting window is without teeth, in particular smooth. Inner tube according to any one of claims 7 to 13, wherein a distal end of the inner tube head (11, 21, 41) is formed by an inner tube head plate (112, 212), which is preferably oriented perpendicular to a longitudinal axis of the inner tube head. Inner tube according to claim 14, wherein the inner tube head plate (112, 212) is designed as a cutting head plate, which is characterized in that a. a recess (1122, 2122) is provided on a radial edge (1121, 2121) of the cutting head plate, b. the recess has at least one cutting edge (1123, 2113) which is oriented at least approximately perpendicular to the longitudinal axis, and wherein.c. the recess and one of the cutting windows (111, 211) merge into one another. Inner tube according to claim 14, wherein the inner tube head plate (112, 212) is designed as a cutting head plate, which is characterized in that a. a recess is provided on a radial edge (1121, 2121) of the cutting head plate for each cutting window, b. each recess has at least one cutting edge, which is oriented in particular at least approximately perpendicular to the longitudinal axis, and wherein c. each recess and one of the cutting windows merge into one another. Inner tube for a surgical cutting instrument with an inner tube head piece (31) at a distal end of the inner tube, wherein the inner tube head piece has a. a milling head (311) provided at a distal end, b. a tapered section (313) located away from the distal end; and c. a connecting piece (312) provided between the milling head and the tapered section; and wherein d.At least one suction window (3131) is provided at the tapered section, through which liquid can be drawn into the inner tube. Inner tube according to claim 17, characterized in that the milling head (311) comprises a plurality of cutting blades, in particular 8 cutting blades, wherein a cutting edge is formed along a radially outer edge of each cutting blade. Inner tube (11, 21, 31, 41) according to any one of claims 7 to 18, characterized in that one or more webs, struts, or braces (4114) are provided in an interior of the inner tube, in particular in a channel formed in the inner tube, each of which extends between two areas offset from each other at least with respect to a circumferential direction on an inner side of the inner tube and / or an inner side of a wall forming the inner tube.Method according to any one of claims 1 to 6, wherein an inner tube according to any one of claims 7 to 19 is obtained by means of the additive manufacturing process. Method or inner tube according to one of the preceding claims, wherein the inner tube and / or the outer tube has a diameter d in the range of a few millimeters, in particular with 2.5mm < d < 10mm, and / or a length / in the range of 15cm < / < 30cm.

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