Surgical drilling instrument

Abstract

Surgical instrument (1) for drilling into bone or bone fragments, comprising a drill section (5), a gear section (2) and an intermediate longitudinal shaft section (3) with a first (30) and a second shaft element (40), characterized in that the second shaft element (40) is at least partially mounted in the first shaft element (30) and each shaft element performs a cyclic translational movement (130, 140) along the longitudinal axis (103) for drilling into the bone.

Description

State of the art

[0001] Various drilling instruments for opening bone are known in the state of the art. These are used to prepare the bone for the insertion of implants, such as osteosynthesis screws. However, all drilling instruments operate according to a rotary principle, in which a drill tip is rotated around an axis. This creates exclusively round openings in the bone.

[0002] DE 10 2014 019 720 B4 relates to a tool for creating a helical cavity in a bone. DE 38 90 886 T5 relates to a drill head for cranial drills. US 10 813 659 B2 relates to a rotary tissue cutting device.

[0003] Implants (e.g., DE102019000965A1, WO2004107957A2, WO03032853A2) are known in the state of the art, which are preferably non-circular in design so that they benefit from their biomechanical advantages due to their shape. However, there is currently no drilling instrument available to prepare the implantation channel for such implants. To date, blade-like implants are driven into the bone by percussion, which can lead to clinical complications. A suitable drilling instrument would have to be capable of creating a non-circular drill channel, and in the case of blade-like implants, the drill channel would even have to exhibit a helical course along the drill depth. Description of the invention

[0004] The task is solved using the drilling instrument (1) according to the invention presented here.

[0005] For the surgical drilling instrument (1) according to the invention, spatial coordinate references are defined, such as a proximal direction (101) and a distal direction (102), which extend along a central axis (103). A radial extension (104) and a circumferential direction (105) are defined extending outward from the central axis (103).

[0006] The surgical instrument (1) according to the invention is suitable for drilling into bones or bone fragments and consists of a drill section (5), a gear section (2), and a longitudinal shaft section (3) located therebetween, comprising a first (30) and a second shaft element (40). The second shaft element (40) is supported at least partially in the first shaft element (30). For drilling, each shaft element performs a cyclical translational movement (130, 140) along the longitudinal axis (103).

[0007] Preferably, the first shaft element (30) has a concentric opening (34) at least in sections along the longitudinal direction (103), and the second shaft element (40) has a concentric outer wall (43) at least in sections along the longitudinal direction (103). It is advantageous if the concentric outer wall (43) of the second shaft element (40) is inserted into the concentric opening (34) of the first shaft element (30). Thus, both shaft elements are aligned and mounted with respect to one another along the central axis (103) without additional means.

[0008] For such a bearing arrangement, it is advantageous if the first shaft element (30) is at least partially tubular, and the second shaft element (40) is at least partially tubular or formed as a solid round rod. A tubular or solid round shape has the advantage that the shaft elements (30, 40) can be manufactured using a lathe, which saves time and thus also reduces costs.

[0009] The gear section (2) essentially consists of a rotor (10) with a central opening (13) and the two shaft elements (30, 40) mounted therein. The two shaft elements (30, 40) each form a cam disc (310, 410) at their proximal end (101). A characteristic of the inventive design is that the first and second shaft elements (30, 40) each form a cam disc (310, 410), and the cam disc of the second shaft element (410) is arranged in the proximal direction (101) relative to the cam disc of the first shaft element (310). This thus constitutes a double-stage cam disc gear. Such an arrangement has the advantage that the parts are easier to manufacture and can be disassembled at any time.

[0010] In order to convert a rotational movement (110) of the rotor (10) into a translational movement (130, 140) of the shaft elements (30, 40), the rotor (10) must have at least two pins (1031, 1041 and / or 1032, 1042), wherein at least one pin (1031 and / or 1032) is engaged in the recess of the first cam disc (313, 312) and at least one further pin (1041 and / or 1042) is engaged in the recess of the second cam disc (413, 412). Rotation of the rotor (110) with the pins (1031, 1032, 1041, 1042) causes the pins to deflect the shaft elements (30, 40) (130, 140) due to the sinusoidal curves (312, 412). They are moved along the longitudinal axis (103).

[0011] If only one pin per cam disc is engaged, a tilting moment occurs on the shaft element. This can lead to one-sided loading, increased wear, and thus jamming. To prevent this, it is advantageous if this tilting moment is suppressed by another opposing pin. More specifically, in an advantageous embodiment, the rotor (10) has at least two circumferentially opposite pins (1031, 1032) that are engaged in the recess of the first cam disc (312), and the rotor (10) has at least two further circumferentially opposite pins (1041, 1042) that are engaged in the recess of the second cam disc (412).

[0012] Only the mechanical solution of inserting the shaft elements into one another allows two cam discs to be placed one behind the other with continuous curves. This design fulfills several mechanical requirements, such as reducing jamming caused by opposing pins, ease of disassembly, easy cleaning, simplified manufacturing, and reduced wear.

[0013] In an alternative embodiment, a counter-rotating cyclic translational movement of the two shaft elements (130, 140) can also be generated by synchronizing the sine waves (312, 412) of the two cam disks (310, 410) in phase. Counter-rotating movement can then be induced by circumferentially positioning pins 1031 and 1041, as well as pins 1032 and 1042, at an angle to each other. This angle and the number of circumferential sine periods determine the phase offset or the degree of counter-rotation of the translational movement (130, 140, 150).

[0014] The surgical instrument (1) can be driven via the rotor (10), which has a proximally extending shaft region (12) providing a coupling connection (11) suitable for transmitting torque to the rotor (110). Handles or rotating drives, such as electrical, electromechanical, mechanical, pneumatic, hydraulic, or other types of drives, can be detachably connected to the surgical instrument (1) at this coupling connection (11). It is important that these drives or handles are suitable for use in the operating room and meet the requirements for cleaning and sterilization.

[0015] To adjust the alignment (108) of the drill section (5) relative to the bone, a stator (20) must be provided. By adjusting the stator (106), the alignment of the drill tip (108, 50) can be adjusted, varied, and / or kept constant. For this purpose, it may be helpful to provide an indicator (25) on the stator (20) that indicates the alignment of the drill tip (51, 106, 108). It is irrelevant whether the indicator (25) is a marking, notch, inscription, relief, material application or protrusion, or whether an additional pointer element is provided.

[0016] For manually holding and adjusting the drill bit-tip alignment (108) using the stator (106), it is important that at least one handle (24) is provided on the stator (20). Handles also include structures suitable for holding the stator (20). These include, for example, notches, grooves, thickened portions, raised roughnesses, depressions, individually protruding handle elements, or even openings (28). The stator (20) can also be part of a housing, which is not shown here.

[0017] In the preferred embodiment, the shaft elements (30, 40) are provided at least partially as a solid round or tubular element. To prevent the shaft elements (30, 40) from rotating relative to one another, it is advantageous if the shaft elements (30, 40) are in direct contact (39, 49) or indirectly (37, 47, 21, 22) with one another along the longitudinal axis (103) in at least one section, so that rotation of the shaft elements (30, 40) relative to one another is excluded. Furthermore, it is also important that no rotation of the shaft elements (30, 40) relative to the stator (20) can occur. For this purpose, a surface or projection (37, 47) must be provided on at least one of the shaft elements (30, 40) which is in contact with the stator (20) so that the shaft element (30 and / or 40) and the stator (20) are always at the same angle (106, 107) to each other in the circumferential direction.

[0018] In order for the surgical drilling instrument (1) according to the invention to be guided over a guide wire (60) and also to be used for minimally invasive interventions, it is advantageous if the entire drilling instrument (1), including the drill section (5), is continuously cannulated (48, 18, 536, 546).

[0019] Drilling is performed using a translatory oscillating drill section (5), wherein the drill section (5) consists of at least two separate drilling elements (53, 54), and these drilling elements are connected to the shaft elements (30, 40). As a result, each drilling element (53, 54) is individually deflected by the drilling instrument (1). The drilling elements have rasp teeth and, when combined, preferably a drill tip (50) that tapers distally. Drilling is performed using a cyclical translatory rasp movement of the drill elements (53, 54), simultaneously drilling and clearing material from the canal.

[0020] The advantage of the instrument (1) according to the invention is that the drilling elements (53, 54) in combination generate openings in the bone that have a non-circular cross-section. Furthermore, it is also conceivable for the opening in the bone to deviate from the central axis (103) along its depth and, for example, to follow a curve. For blade-like implants, it is necessary and also possible for the drilling elements (53, 54) in combination to form a blade shape (52). When drilling with a translatorily oscillating blade (52), it is then also possible to generate openings in the bone, wherein the opening has a first cross-section and a second cross-section at two different depths, and the orientations of the two cross-sections are different from one another. Brief description of the drawings show: Fig. 1 an oblique view of the drilling instrument according to the invention, Fig. 2 an oblique view of an exploded view without drill section, Fig. 3 a side view of the drilling instrument according to the invention, as well as a detailed view in section, Fig. 4 Side view of the shaft elements showing the development of the cam discs, Fig. 5 an alternative embodiment with three or more shaft elements Fig. 6 is an oblique view of the drilling instrument according to the invention, demonstrating that the drill section can be detachably connected, Fig. 7a,b Detail and exploded view of the drill section Fig. 8a-d various views of the drill section, Fig. 9a,b alternative design of the drill section with cannulation and guide wire, Fig. 10 alternative design of the drilling instrument, Fig. 11 Design form from Fig. 10 illustrated without stator for better visibility, Fig. 12a-c Release mechanism for easy disassembly of the gear section for instrument preparation, Fig. 13a,b Individual representation of the alternative design form from Fig. 10. Description of the preferred embodiments

[0021] The Fig. Figure 1 shows the general structure of the drilling instrument (1) according to the invention. It consists of a gear section (2), an adjoining shaft region (3), a drill section (5) ending distally (102), and a connecting section (4) located therebetween. In the proximal direction (101) there is a rotor (10) which, with the aid of a gear (2), converts a rotational movement (110) into a cyclical translational movement (130, 140) of the shaft elements (30, 40) along the central axis (103). With the aid of a stator (20), the alignment (106) of the drill section (5, 108) and also of the shaft region (3) can be adjusted and maintained (120). Thus, the rotor (10) rotates in relation to all instrument components which are in the same alignment (106) with the stator (20).

[0022] The shaft region (3) preferably extends longitudinally along a central axis (103). This allows a main orientation and thus also the central axis (103) on the instrument (1) to be defined. A longitudinal extension of the shaft region (3) has the advantage of being able to generate openings in bone that are otherwise difficult to reach due to the enclosed soft tissue. The shaft region (3) consists of at least two shaft elements (30, 40). The drill section (5) has individually deflectable or movable drill elements (53, 54) that are in contact with one another but are not firmly connected to one another. Each shaft element (30, 40) is mechanically connected to a drill element (30 with 53 and 40 with 54). A movement (e.g. translation) deflects the respective drill element (53, 54). If two shaft elements (30, 40) are provided, the drill elements (53, 54) preferably move in opposite directions for drilling.This allows openings to be created in the distal direction (102) without rotating the drill elements (53, 54). The openings are hammered or rasped vertically into the bone.

[0023] Fig. Figure 2 shows the detailed structure of the drilling instrument (1) according to the invention in an exploded view. In this embodiment, the second shaft element (40) is almost completely inserted into the first shaft element (30). Both shaft elements (30, 40) are designed as tubes, which reduces manufacturing costs. At the respective distal end of the shaft elements there is a threaded section (35, 45) which serves as a detachable connection to the drill elements (53, 54) (not shown here). Both shaft elements (30, 40) each have a cam disk (310, 410) with an outwardly directed outer surface (311, 411). Further details on the cam discs (310, 410) with their outer surfaces (311, 411), recesses (313, 413) and their curves (312, 412) can be found in Fig. 4. Both cam discs (310, 410) are mounted in the rotor (10) for rotation and translation. This creates a counter-rotating translational movement (130, 140) within the rotor (10), which leads to a cyclical shortening and spacing between the walls of the cam discs, which are perpendicular to the central axis (103). This compresses and expands the enclosed spaces. Preferably, various openings (314, 414) are provided to ventilate these enclosed spaces and prevent a blocking pumping effect.

[0024] Furthermore, Fig. 2 Details of the rotor (10). The rotor (10) is primarily round and has a concentric opening (13) open towards the distal end (102). In the proximal direction (101), the rotor (10) is preferably closed and merges into a shaft (12). A drive section (11) containing elements of a quick-coupling is provided on this shaft (12). This drive section (11) is suitable for connecting various drive mechanisms that transmit a rotary movement (110) to the rotor (10). Two or more openings (14) are provided on the rotor (10), which are aligned in the radial direction (104) and run towards the central axis (103). These openings (14) thus communicate with the concentric opening (13) of the rotor. Two or more pins (1031, 1032, 1041, 1042) are fixed, joined or mounted in these openings (14).When assembled, the pins protrude into the interior of the concentric opening (13) of the rotor and are in engagement with the cam discs (310, 410), as shown in . Fig. 3 shown. Fig. Figure 2 further shows the essential details of the stator (20). The stator has surfaces or walls (21, 22) that are suitable for direct contact with the surfaces or walls (37, 47) of the shaft elements (30, 40). The contact surfaces are designed such that they tolerate a translational relative movement between the stator (20) and the shaft elements (30, 40), but at the same time the alignment (106) in the circumferential direction (105) between the stator and the drill section (108) is kept constant. In the preferred embodiment of the drilling instrument (1), a keyhole-like opening (23) is provided on the stator (20), through which the shaft elements (30, 40) can be inserted from the proximal end in the assembled assembly.

[0025] Furthermore, it is advantageous if an indicator or marking (25) is provided on the stator (20), which indicates the orientation of the drill section (5, 108). For manual holding (120) of the stator (20), it is advantageous if one or more handles or grip features (24, 28) are present on the stator (20) to facilitate gripping. In the embodiment shown here, for mounting the instrument, the pins (1031, 1032, 1041, 1042) can be inserted through the openings of the stator (28) and fastened to the rotor (10) with the aid of a tool.

[0026] Fig. 3 shows a sectional view of the Fig. 2 and thus provides an insight into the assembly and functioning of the drilling instrument (1) according to the invention, the functioning and interaction of the components having already been described at the beginning. It can also be seen that the rotor (10) is arranged in such a way that it rotates around the central axis (103). Only through this arrangement is it possible for the entire instrument to be cannulated (18, 48) and for the gear to rotate around an inserted guide wire (60). This is also the case, for example, in Fig. 9a and b.

[0027] In an alternative embodiment (not shown), it would also be conceivable for an additional rotary drilling element to be located within the cannulation (48) and directly connected to the rotor (10). The drilling element can protrude distally from the instrument and rotates together with the rotor (10) relative to the drill section (5). The internally rotating drilling element can be used to generate a centering hole before the translational drilling section (53, 54) automatically follows.

[0028] As in Fig. 4, the cam discs (310, 410) each have a radially outwardly directed surface (311, 411). The outer diameters of the surfaces 311 and 411 are approximately the same size. Each of the surfaces has a recess (313, 413) directed towards the central axis (103) in the radial direction (104), and this recess runs in the circumferential direction (105) along the surface (311, 411) and forms a closed curve (312, 412). In a developed view ( Fig. 4), this curve can be represented sinusoidally, whereby it is advantageous that the sine wave (312, 412) on the outer surface (311, 411) is provided axially symmetrically with respect to the longitudinal axis (103). This allows more than one translational deflection of the shaft elements (30, 40) to be achieved per revolution of the rotor (10). If two or more pins are provided per cam disc in the rotor, at least two or a multiple of two sine waves must be provided per curve.

[0029] For mutual deflection of the shaft elements (30, 40), it is advantageous if the sinusoidal curve (312) of the first shaft element (30) is phase-shifted relative to the sinusoidal curve (412) of the first shaft element (40). In the embodiment shown, the phase shift optimally corresponds to between 20% and 80%, but preferably approximately 50%, of the oscillation period of the sine wave.

[0030] It is advantageous that the curve (312, 412) is sinusoidal in a developed representation and the translation path of the shaft element (130, 140) is defined by the maxima (319, 419) of the sine wave ( Fig. 4). In relation to the rotor (10), the translational path of the first and / or second shaft element (130, 140) is between 0.1 mm and 5 mm, preferably 0.2 mm and 4 mm, preferably 0.5 mm and 3 mm. Depending on the phase offset of the cam discs relative to one another, the translational path (150) relative to the two drilling elements (53, 54) is the sum of the individual deflections (150 = 130 + 140). In the preferred embodiment with two shaft elements (30, 40), the translational path (150) of the first shaft element (30) relative to the second shaft element (40) is approximately twice the translational path (130, 140) of a shaft element relative to the rotor (10). This has the advantage that the individual deflections of the shaft elements (130, 140) on the cam discs can be smaller than those actually occurring at the drill section (5, 150) for drilling. This ensures less wear in the gear section (2).

[0031] An alternative embodiment is shown in Fig. 5. In addition to the preferred variant with two shaft elements (30, 40), more than two shaft elements are also conceivable, as shown here with three shaft elements (30, 40, and 500). Any number of shaft elements can be nested together, with a cam disk (310, 410, and 510) provided at the proximal end of each shaft element. The number of shaft elements also defines the number of drill elements.

[0032] For drilling with two shaft elements (30, 40) that move cyclically in opposite directions, a drill section (5) is provided, wherein the drill section (5) consists of two separate but directly contacting drilling elements (53, 54), and a first drilling element (53) is connected to the first shaft element (30) and a second drilling element (54) is connected to the second shaft element (40). It is advantageous for the application if the drilling elements (53, 54) are connected individually or as a whole in a detachable or replaceable manner to the shaft elements (30, 40) ( Fig. 6).

[0033] The drilling principle presented here allows for the creation of openings with any cross-section, e.g., round, triangular, square, polygonal, or other shapes. For the initially stated task of generating openings for blade-like implants, the drilling instrument (1) presented here offers the technical possibility of creating openings with the profile of a blade in the bone. Furthermore, it is also possible to create a helical depth profile for the blade profile. In order to prepare a drilling channel for a blade-like implant, it is advantageous if the drilling elements (53, 54) together form a blade shape (52) ( Fig. 7a and b) and at least one of the drilling elements (53, 54) forms at least one blade wing (52). Shown here are two wings that together describe a blade shape (52). In the embodiment shown here, the drill section (5) can be divided into two descriptive features: a drilling core (56) and the wings (52) adjoining it ( Fig. 7a, Fig. 7b, Fig. 8a-d).

[0034] The drill core (56) has a drill tip (50) that tapers in the distal direction. A drilling area (51) extends from this drill tip (50) in the proximal direction (51), which sets the contour and dimensions of the core profile to be drilled. This is also the area with the largest cross-section. Adjacent to this area (51) and continuing in the proximal direction, the drill core (56) has a reduced cross-section so that this area no longer exerts a drilling effect and the drilling resistance is reduced. Furthermore, material removed in the resulting gap can be removed in the proximal direction. It is advantageous if at least the drill tip (50) and the drilling area (51) are equipped with rasp teeth (57). Teeth (57) are particularly suitable for rasping, as they perform a cutting action in the pulling direction of the drill elements (53, 54) and can be easily inserted into the material in the pushing direction. As shown ( Fig. 8b and Fig. 8d), barb-like rasp teeth are best suited for this purpose. The easier penetration in the push direction compared to rasping / machining in the pull direction also creates automatic propulsion into the material to be drilled. Of course, differently designed rasp or saw teeth with different angles or even undercuts are also conceivable.

[0035] In addition to the drill core (56) of the drill section (5), wings (52) or a blade shape are provided in the preferred embodiment. The wings (52) preferably have a first proximal orientation (107) and a second orientation in the distal direction (108) ( Fig. 7a, Fig. 8c). If a drill channel is intended for straight blade-like implants, the two orientations (107, 108) must not differ. The wings run primarily parallel along the central axis (103). For curved blade-like implants, however, the orientations (107, 108) must be different from each other and form a helix. The blade-like implant and the drill section should correspond at least in some sections. This applies primarily to the number of wings and the defined pitch of the wings. It is also advantageous if the wings (52) merge distally into the drill core (56) and if rasp teeth (58) are formed at least in this transition area. These rasp teeth (58) are in contact with the material to be drilled and have a cutting and abrasive character. A barb-like profile is also suitable here.The teeth are used to shape the profile of the blades to be drilled into the material.

[0036] Pockets (59) can optionally be provided in or on the wings (52) so that the removed material can escape and be removed from the drill channel ( Fig. 8a, Fig. 8d). The pockets are separated by outer edges of each wing (533 and 543). Depth indicators (55) are preferably provided on the drilling elements (53, 54) to provide the user with an indication of the current drilling depth.

[0037] During the cyclical deflection of the drill elements (130, 140), the cross-section of the drill elements changes due to the offset of the drill elements relative to one another (150). In the central position, the cross-sectional area is maximum, so that both drill elements (53, 54) form the drill channel at this position. A deflection position of the drill elements starting from this central position enables distal advancement into the material when the drill elements are offset. The proximally moving drill element transports the rasped material proximally and simultaneously supports itself with the rasp teeth (57, 58) on the inner wall of the drill channel in order to provide a counter-bearing for the opposite, distally moving drill element. This arrangement of the rasp teeth in combination with the translational rasp movement reduces the forces required for drilling, since the drilling instrument (1) draws itself into the material to a certain extent.Furthermore, the drill cross-section is reduced during a translational deflection movement from the center position, so that the drilling elements in the drilling channel no longer block each other and space is created for the translational movement in the drilling channel.

[0038] To ensure that the drill elements (53, 54) run in alignment with each other, they can have a guide structure or profile (532, 542). Different profiles are suitable for this purpose, preventing lateral slippage of the two drill elements (53, 54). This function can also be fulfilled by a guide wire (60) as an additional component. Both drill elements have a partial cutout of a cannulation opening (536, 546) ( Fig. 9a and Fig. 9b).

[0039] It is important for successful use in clinical practice that surgical instruments can be disassembled for cleaning so that all surfaces and cavities of the individual parts can be rinsed and cleaned. When assembled, this is difficult for more complex instruments. It is therefore important that at least the gear section with the moving parts can be disassembled. For this purpose, it is advantageous if the pins (1031, 1041, 1032, 1042) can be detachable from the rotor (10). This can be achieved either by a thread. Alternatively, other plug-in or detachable joining methods are conceivable. It is also possible for the pins to be provided in groups of two, or for the rotor to have a multi-part structure, for example, and thus the shaft elements (30, 40) can be released from the rotor.

[0040] In an alternative embodiment, the rotor (10) has an outer sleeve (19) which is movable in the longitudinal direction ( Fig. 10-11).

[0041] The outer sleeve can assume a first position (191) in which the inner pin spacing 1033 is smaller than the inner diameter 130 of the opening of the rotor (13) ( Fig. 12a-c). The outer sleeve (19) can assume a second position (192) in which the inner pin spacing 1033 is equal to or greater than the inner diameter 130 of the opening of the rotor (13). This means that as soon as the pins (1031, 1032, 1041, 1042) are released or moved in the radial direction (104), the shaft elements (30, 40) can be removed from the rotor (10).

[0042] This alternative embodiment also shows how the structure is designed in which the first shaft element (30) is only partially mounted in the second shaft element (40) ( Fig. 12a and Fig.12b). This design allows both shaft elements (30, 40) to already have surfaces or walls (39, 49) that are in direct contact with each other and prevent rotation of the two shaft elements relative to each other. It is also illustrated that the drill elements (53, 54) can be formed integrally with the shaft elements (30, 40), if the manufacturing strategy permits.

Claims

[1] Surgical instrument (1) for drilling into bones or bone fragments, comprising a drill section (5), a gear section (2) and a longitudinal shaft section (3) located therebetween with a first (30) and a second shaft element (40) characterized by that the second shaft element (40) is mounted at least in sections in the first shaft element (30) and each shaft element performs a cyclical translational movement (130, 140) along the longitudinal axis (103) for drilling. [2] Surgical instrument (1) according to the preceding claim, characterized by that the first shaft element (30) has at least one opening (34) which is partially enclosed along the longitudinal direction (103) but completely enclosed in the circumferential direction (105). [3] Surgical instrument (1) according to the preceding claim, characterized bythat the second shaft element (40) has at least in sections a concentric outer wall (43) and the concentric outer wall (43) of the second shaft element (40) is inserted into the opening (34) of the first shaft element (30). [4] Surgical instrument (1) according to one of the preceding claims, characterized by that the first shaft element (30) is tubular at least in sections. [5] Surgical instrument (1) according to one of the preceding claims, characterized by that the second shaft element (40) is at least partially tubular or formed as a solid round rod. [6] Surgical instrument (1) according to one of the preceding claims, characterized by that both shaft elements (30, 40) each form a cam disc (310, 410) at their proximal end (101). [7] Surgical instrument (1) according to one of the preceding claims, characterized bythat the first and second shaft elements (30, 40) each form a cam disc (310, 410), and the cam disc of the second shaft element (410) is arranged in the proximal direction (101) to the cam disc of the first shaft element (310). [8] Surgical instrument (1) according to one of the preceding claims, characterized by that the cam discs (310, 410) each have a radially outwardly directed lateral surface (311, 411) and the outer diameters of the lateral surfaces 311 and 411 are approximately the same size. [9] Surgical instrument (1) according to one of the preceding claims, characterized by that the cam discs (310, 410) each have a lateral surface (311, 411) and the lateral surfaces have a recess (313, 413) directed towards the central axis (103) in the radial direction (104), and this recess runs in the circumferential direction (105) along the lateral surface (311, 411) and forms a closed curve (312, 412). [10] Surgical instrument (1) according to claim 9, characterized by that the curve (312, 412) is sinusoidal in a developed representation and the translation path of the shaft element (130, 140) is defined by the maxima (319, 419) of the sine wave. [11] Surgical instrument (1) according to one of the preceding claims, characterized by that, in relation to the rotor (10), the translation path of the first and / or second shaft element (130, 140) is between 0.1 mm and 5 mm, preferably 0.2 mm and 4 mm, preferably 0.5 mm and 3 mm. [12] Surgical instrument (1) according to one of the preceding claims, characterized by that the translation path of the first shaft element in relation to the second shaft element (150) corresponds approximately to twice the translation path of a shaft element (130 or 140) in relation to the rotor (10). [13] Surgical instrument (1) according to claim 9, characterized bythat the curve (312, 412) is sinusoidal in a developed representation and the sine wave (312, 412) is provided on the lateral surface (311, 411) in an axially symmetrical manner with respect to the longitudinal axis (103). [14] Surgical instrument (1) according to one of the preceding claims, characterized by that the sinusoidal curve (312) of the first shaft element (30) is phase-shifted with respect to the sinusoidal curve (412) of the first shaft element (40). [15] Surgical instrument (1) according to claim 14, characterized by that the phase shift corresponds to between 20% and 80%, but preferably approximately 50%, of the oscillation period of the sine wave. [16] Surgical instrument (1) according to one of the preceding claims, characterized by that the shaft elements (30, 40) are mounted at their proximal ends with the cam discs (310, 410) within a rotor (10) in a rotational and translational manner. [17] Surgical instrument (1) according to one of the preceding claims, characterized by that the rotor (10) has at least two pins (1031, 1041 and / or 1032, 1042) and at least one pin (1031 and / or 1032) is engaged in the recess of the first cam disc (312) and at least one further pin (1041 and / or 1042) is engaged in the recess of the second cam disc (412). [18] Surgical instrument (1) according to claim 17, characterized by that the rotor (10) has two circumferentially opposite pins (1031, 1032) which are engaged in the recess of the first cam disc (312), and the rotor (10) has two further circumferentially opposite pins (1041, 1042) which are engaged in the recess of the second cam disc (412). [19] Surgical instrument (1) according to one of the preceding claims, characterized bythat the pins 1031 and 1041 as well as the pins 1032 and 1042 are placed at an angle to each other in the circumferential direction. [20] Surgical instrument (1) according to one of the preceding claims, characterized by that the pins (1031, 1041, 1032, 1042) are detachable from the rotor (10). [21] Surgical instrument (1) according to one of the preceding claims, characterized by that the rotor (10) has an outer sleeve (19) which is movable in the longitudinal direction, and this outer sleeve can assume a first position (191) in which the inner pin spacing 1033 is smaller than the inner diameter 15 of the opening of the rotor (13), and the outer sleeve (19) can assume a second position (192) in which the inner pin spacing 1033 is equal to or greater than the inner diameter 15 of the opening of the rotor (13). [22] Surgical instrument (1) according to one of the preceding claims, characterized bythat as soon as the pins (1031, 1032, 1041, 1042) are released or moved in the radial direction, the shaft elements (30, 40) can be removed from the rotor (10). [23] Surgical instrument (1) according to one of the preceding claims, characterized by that the rotor (10) has a proximally extending shaft region (11) which provides a coupling connection suitable for transmitting a torque to the rotor (10). [24] Surgical instrument (1) according to one of the preceding claims, characterized by that the shaft elements (30, 40) are in contact with one another directly (39, 49) or indirectly (37, 47, 21, 22) along the longitudinal axis (103) at least in one section and thus rotation of the shaft elements (30, 40) relative to one another is excluded. [25] Surgical instrument (1) according to one of the preceding claims, characterized bythat a stator (20) is provided which serves as a reference (106) for aligning the drill section (108). [26] Surgical instrument (1) according to one of the preceding claims, characterized by that the stator (20) has an indicator (25) which shows the orientation of the drill tip (51, 108). [27] Surgical instrument (1) according to one of the preceding claims, characterized by that the stator (20) has at least one handle. [28] Surgical instrument (1) according to one of the preceding claims, characterized by that on at least one of the shaft elements (30, 40) a surface or projection (37, 47) is provided which is in contact with the stator (20, 6), so that the shaft element (30 and / or 40) and the stator (20) are always at the same angle to one another in the circumferential direction. [29] Surgical instrument (1) according to one of the preceding claims, characterized bythat the entire drilling instrument (1) including the drill section (5) is continuously cannulated (48, 18, 536, 546) and a guide wire (60) can be accommodated therein. [30] Surgical instrument (1) according to one of the preceding claims, characterized by that the drill section (5) consists of two drilling elements (53, 54) which are separate from one another but in direct contact, and a first drilling element (53) is connected to the first shaft element (30) and a second drilling element (54) is connected to the second shaft element (40). [31] Surgical instrument (1) according to one of the preceding claims, characterized by that the drilling elements (53, 54) are detachably connected to the shaft elements (30, 40). [32] Surgical instrument (1) according to one of the preceding claims, characterized by that the drilling elements (53, 54) in combination generate openings in the bone which have a non-circular cross-section. [33] Surgical instrument (1) according to one of the preceding claims, characterized by that the drilling elements (53, 54) in combination generate openings in the bone which deviate along the depth from the central axis (103). [34] Surgical instrument (1) according to one of the preceding claims, characterized by that the drilling elements (53, 54) form a blade shape (52) in combination. [35] Surgical instrument (1) according to one of the preceding claims, characterized by that the drilling elements (53, 54) generate openings in the bone in combination, and the opening has a first cross-section and a second cross-section at two different depths and the orientations of the two cross-sections are different.

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