Flexible surgical tool with integral bearing assembly - Patents.com

Abstract

The present invention relates to a surgical tool (1) configured to be inserted into an instrument shaft (16, 17) of a surgical instrument (15), and the surgical instrument (15). The surgical tool (1) includes a distal tool tip (2), a tool shaft (3, 4, 5), and a bearing bush (8). The tool shaft (3, 4, 5) is provided to extend proximally from the distal tool tip (2) and has a bearing portion (3) located distally and a drive portion (5) located proximally of the bearing portion (3). The drive portion (5) is configured to engage a drive shaft (20) of the surgical instrument (15). The bearing bush (8) is axially fixedly attached to the bearing portion (3) when not inserted into the surgical instrument (15), and has a bearing coupling element (10) for releasably coupling to the instrument shaft (16, 17) of the surgical instrument (15).

Description

[Technical field]

[0001] The present invention relates to surgical instruments and surgical tools attached or attachable to the surgical instruments.

[0002] In surgical techniques, it is advantageous to have the distal shaft portion of a handheld medical instrument shaft bendable at an angle, allowing surgery to be performed in tight spaces, for example in spinal surgery. [Background technology]

[0003] Medical instruments with bendable, angled distal tips have long been known in the field of surgical robotics, allowing precise manipulation of the instruments in the tightest of spaces. However, there are no rotating tools with bendable angles for this type of instrument. One example is the Da Vinci surgical robot from Intuitive Surgical.

[0004] There are various medical instruments on the market that can be bent at an angle. For example, Human Xtensions has developed a forceps that can be bent at an angle. Using a handheld robotic instrument, the surgeon can convert gross hand movements into fine movements of the instrument tip. By using this instrument, the instrument tip can be bent at an angle in a flexible section that is about 20 mm long. Such a flexible section is supported by a kind of plastic stent. The adjustment is made by a wire strand that is led through the outside of the stent. The disadvantages in this case are the length of the bending area and the very flexible tip. The flexibility is provided by the plastic stent and the wire strand.

[0005] Furthermore, there are already manufacturers of cutting handpieces (hand-held medical instruments) that can be bent to create angles. Such instruments are mainly used in endoscopic spinal surgery, allowing minimally invasive techniques and easy processing of structures that are difficult to access in this area. The coupling structure of such cutting handpieces has a fairly open design and a certain degree of flexibility. This means that when pressure is applied to the tip of the cutter, the angle changes slightly. Furthermore, such cutting handpieces can only be bent at a maximum angle of 36°. An example of this is the cutting handpiece from Joimax.

[0006] Furthermore, there are also high-speed cutting handpieces (hand-held medical instruments) with shafts that can be bent at angles. With interchangeable shafts, the handpiece can be bent at three angles: 0°, 7.5°, and 15°. The biggest drawback is the large bending radius required to achieve the angulation, which takes up a lot of space and limits the operating options at the operating site. Furthermore, the angle cannot be adjusted during the operation. The fixed bending angle of the shaft means that the shaft cannot be inserted into the straight working channel of the endoscope, making endoscopic work with the shaft impossible. Furthermore, the maximum bending angle of 15° is not particularly large.

[0007] From the disclosures of DE 10 2017 010 033 A1 and US 10 178 998 A1 milling cutters are known which have a head which can be bent to give an angle. The technology of both documents is realised through a fork joint. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] DE 102017010033 [Patent Document 2] U.S. Pat. No. 1,017,898 Summary of the Invention

[0009] The present invention is based on the task of alleviating or avoiding the drawbacks of the prior art, in particular by providing a surgical tool, a surgical instrument and / or a system relating thereto that is simple, inexpensive and allows fast and precise guidance.

[0010] The problem underlying the present invention is solved by a surgical tool, a surgical instrument and a related system according to the features of the independent claims. Advantageous embodiments are the subject of the dependent claims and are detailed below.

[0011] More specifically, the problem is solved by a surgical tool configured to be inserted into an instrument shaft of a surgical instrument. The surgical tool has a distal tool tip (e.g., a drill or cutter). The surgical tool further has a tool shaft extending proximally from the distal tool tip, the tool shaft having a bearing portion located distally and a drive portion located proximally of the bearing portion. The drive portion is configured to engage (e.g., closely engage, mate) with the drive shaft of the surgical instrument. The surgical tool further has a bearing bush attached to the bearing portion and a bearing coupling element for detachably coupling to the instrument shaft of the surgical instrument (particularly the distal instrument shaft portion thereof).

[0012] In other words, a surgical tool for incorporation into a surgical instrument (in particular a handpiece, a hand-held instrument) is provided that is integrally equipped with a bearing assembly. The surgical tool has a tool head (tool tip) that is adapted to act on, for example, human tissue, bone, etc., and a tool shaft on whose distal end the tool head (tool tip) is arranged. The tool shaft is adapted to be inserted (from the distal direction) into an instrument shaft of a surgical instrument (in particular a hand-held instrument) and to be coupled to a drive provided by the surgical instrument for driving the tool tip (tool head) in the instrument shaft. Furthermore, the surgical tool has a bearing element (bearing bush) that is attached (in particular directly) to the tool shaft proximal to the tool head (tool tip). The bearing element (bearing bush) can be fixed to the instrument shaft together (integrally) with the surgical tool.

[0013] More specifically, the surgical tool (particularly the tool shaft and the bearing bush) is configured to be inserted into the distal end of the instrument shaft. In particular, when the surgical tool is not inserted into the surgical instrument, the bearing bush is attached to the bearing part of the tool shaft in an axially fixed manner. In other words, when the surgical tool is present alone, i.e. when not inserted into the instrument shaft, the bearing bush is preferably connected to at least the bearing part of the tool shaft in an axially fixed manner. Preferably, the bearing bush has a larger diameter than the entire tool shaft proximal to the bearing bush, and preferably compared to the entire surgical tool proximal to the bearing bush. In particular, the bearing bush has a larger diameter than the drive part of the tool shaft. More preferably, the entire bearing bush is arranged distal to the drive part. Preferably, the bearing bush has an inner ring connected to the bearing part in a substantially axially and rotationally fixed manner. More preferably, the bearing bush has an outer ring provided in a manner that is rotatable relative to the inner ring (and axially fixed except for the bearing clearance). The bearing coupling element is preferably provided on the outer ring (in particular on the radially outer surface of the outer ring). Preferably, the surgical tool has a seal, in particular in the form of a cover disk, at or distal to the distal end of the bearing bush, which may in particular reduce or prevent dirt and / or fluids from penetrating into the bearing bush and into the instrument shaft. Preferably, only a tool tip (possibly only a tool tip and a seal) is arranged on the distal side of the bearing bush. Preferably, no components (except possibly a seal) are arranged on the distal side of the bearing bush, which directly interact (engage) with the instrument shaft located radially outside the bearing bush.

[0014] Such surgical tools and instruments allow high speeds at low temperatures and precise positioning of the tool tip (tool head), which ensures a consistent protrusion of the tool tip (tool head) from the distal end of the instrument shaft. The special tool configuration allows precise surgical tool guidance, unhindered movement, and optimal docking of the surgical tool within the housing of the surgical instrument. Furthermore, assembly and disassembly of the surgical tool is particularly simple.

[0015] Preferably, the tool shaft further comprises a flexible section between the bearing section and the driving section, which is flexible in bending and torsionally rigid. This ensures precise positioning and very smooth operation of the surgical tool while allowing the tool tip to be bent at an angle relative to the tool shaft and the instrument shaft. The flexible section allows the surgical tool to be operated both in an angular position of 0° and in an angular position when bent (e.g., 45°) and to transmit torque. For example, the flexible section may be connected to the bearing section at its distal end, for example via a fork or a receiver (recess) of the bearing section. Alternatively or additionally, the flexible section may be connected to the driving section at its proximal end, for example via a fork or a receiver (recess) of the driving section. The thickened wall of the bearing part in the region of the fork or the receiving part (recess) can simultaneously function as an enlarged shoulder (radial shoulder) for abutting against the bearing bush.

[0016] In particular, the bending angle of the tool tip relative to the tool shaft may be between 30° and 60°, preferably at least 45°. The curvature of the flexible section is externally dictated by the bending of the instrument shaft, so that only a small axial length is required for bending.

[0017] Such a flexible section can be provided, for example, by specially braiding the individual strands. The flexible section may in particular have a torque strand consisting of several alternating layers with different winding directions. In other words, the flexible section may have a first sleeve made of individual strands (fibers) wound in a first direction and a second sleeve (rigidly connected to the first sleeve) made of individual strands (fibers) wound in a second direction. In this way, clockwise and counterclockwise rotations can be realized without the strands themselves twisting and breaking.

[0018] In particular, the drive part and / or the bearing part are configured to be resistant to bending and torsion, for example in rod-like or tubular form, which allows a particularly precise coupling of the surgical instrument to the drive part or a particularly good support via the bearing bush.

[0019] More specifically, the surgical tool is a rotationally driven tool, in particular a cutting or drilling tool.

[0020] Advantageously, the bearing bush has a proximal front surface (proximal end surface) which forms a stop surface (contact surface) for contacting the instrument shaft (in particular the distal shaft part). This allows for a precise positioning of the tool tip relative to the instrument shaft and ensures a constant projection of the tool tip from the distal end of the instrument shaft for every adjustable angle of the tool tip relative to the tool shaft. Furthermore, the stop surface (contact surface) provided on the proximal side of the bearing bush prevents the tool tip from being loaded by a corresponding load to the flexible part, preventing the latter from being compressed or overloaded during operation.

[0021] Preferably, the bearing coupling element forms a radially inward recess or a radially outward protrusion in the circumferential wall of the bearing bush. For example, said recess may be provided in the form of a circumferentially extending groove (circumferential groove). For engaging (latching) said recess or said protrusion of the bearing coupling element, a suitable counter coupling element, i.e. a latch mechanism (e.g. a mechanism with a latch body in the form of a ball pressure element), may be provided on the radially inner side of the instrument shaft, for example in the form of a click connection. This allows in particular a quick and easy assembly and a simplified positioning of the bearing bush relative to the instrument shaft, in particular in the axial direction. The housing of the bearing bush ensures a safe and easy insertion of the surgical tool into the instrument shaft during the coupling process.

[0022] More preferably, the bearing bush provides a single-row, even more preferably a double-row roller bearing (miniature roller bearing / ball bearing) with one or two roller bearing lengths. The roller bearing may comprise a deep groove ball bearing or an angular ball bearing. Angular ball bearings have the advantage of a high load-bearing capacity and easy assembly. This simultaneously results in suitability for high drive speeds and low surgical tool temperatures. In the case of double-row roller bearings, a particularly smooth running and a particularly low tool temperature are achieved and the risk of the surgical tool tilting is particularly minimized. This results in particular in a stable surgical tool and little load on the flexures.

[0023] In particular, the bearing bushes of the double row roller bearing have radially inner spacer bushes and / or preloading elements (biasing elements) which axially position the two roller bearings relative to each other. In other words, the spacer bushes are arranged between the individual bearings and contact them, for example on the inner ring, to determine the relative position of the bearings relative to each other. The preloading elements (biasing elements), which may for example be corrugated spring washers, may be inserted between one of the bearings and the housing part of the bearing bush. Thereby, the preloading elements (biasing elements) may preload (bias) the adjacent bearing axially outwardly relative to the corresponding other bearing. In this way, the tolerances of the components are compensated, the service life of the bearings or bearing bushes may be extended and the noise level may be reduced. Preferably, the bearing bush may have a cover disk, especially on its distal side. Thereby, the corresponding adjacent bearings are protected against mechanical damage and possibly (if they act as sealing washers) against the ingress of liquids.

[0024] Preferably, the bearing bush is axially mounted between the bearing part and the distal tool tip (e.g. between a first circumferential step on the bearing part and a second circumferential step on the distal tool tip). For example, the distal tool tip may be screwed (screwed) into the bearing part. For example, the distal tool tip may form an internal thread that is screwed into the external thread of the bearing part. This means that no additional elements need to be provided to fasten the bearing bush to the tool shaft. Optionally, the bearing part may be (integrally) connected to the tool tip. The bearing bush may be fixed to the bearing part via a threaded nut or the like.

[0025] Advantageously, the drive part forms at least one axially extending engagement part, in particular a profile shaft part having a predetermined profile, for example a hexagonal shape. An axially extending engagement part, in particular a part having a constant cross-sectional shape along the axial direction, allows a longitudinal displacement between the drive part and the drive shaft. Such a displacement can occur, for example, when the flexible part is bent at an angle. Furthermore, the profile shaft part is particularly suitable for absorbing the drive torque. In the coupled state, the surgical tool is securely connected to the tube (drive shaft) and can thus be driven by a motor in the surgical instrument (hand piece, instrument handle). The tube (drive shaft) is securely connected to an engagement receptacle, for example having a hexagonal geometric shape, to rotate the surgical tool over the engagement receptacle, for example a milling head can remove material.

[0026] Preferably, the length of the engagement portion is equal to or greater than the maximum displacement distance (maximum axial displacement distance) of the proximal end of the flexible portion at the maximum curvature of the flexible portion. This protects the overlap (engagement state) of the engagement portion and the engagement receiver of the drive shaft cooperating with the engagement portion, and thus the torque transmission, regardless of how much the tool tip is bent relative to the tool shaft. In other words, a displacement (change in length) may occur in the proximal region of the surgical tool. This is due to the fixation of the distal end of the instrument shaft and the surgical tool via the bearing bush, the change in the guide of the surgical tool when bent at an angle, and the resulting change in the bending shape of the flexible portion. The corresponding length correction in the proximal region is achieved by the length (axial expansion) of the drive engagement portion (predetermined profile shaft portion) (e.g. hexagonal). In other words, the engagement portion and the engagement receiver are formed so that they can be moved axially relative to each other almost freely (without stopping). As a result, the driven length of the engagement portion is shortened by several millimeters. This can be taken into account in the overall length of the engagement to ensure reliable transmission of torque.

[0027] Advantageously, the drive part forms a proximal centering end, in particular a centering tip with a plurality of chamfered side walls. This facilitates the insertion of the drive part into the drive shaft, since the centering tip can compensate for misalignment between the drive part and the drive shaft. More preferably, the centering tip forms a profile, in particular with a triangular pyramid shape, which is adapted to engage with a counter profile of the surgical instrument in a rotationally positioned manner. A profile of the proximal centering tip is to be understood as a part having an at least partially aligned profile in the axial direction (i.e. a shape that is not continuously rotationally symmetric). This ensures that a profile can be associated with a counter profile that matches only in one (or a certain number of) specific rotational positions.

[0028] Alternatively or additionally, the problem underlying the present invention is solved by a surgical instrument having an instrument shaft that is open in the distal direction and that is adapted to receive a surgical tool according to any one of the claims. The instrument shaft has a distal instrument shaft section that is provided with a counter coupling element or latch mechanism. The distal instrument shaft section is adapted to be releasably coupled to a bearing coupling element of the surgical tool. In particular, the latch mechanism is an elastically biased or prestressable latch mechanism. In other words, the latch mechanism may have an engagement element that is connected to the distal instrument shaft section via a spring element. The engagement element may be prestressed by the spring element, in particular radially inwards. Furthermore, the instrument shaft comprises a proximal instrument shaft section that has a drive shaft that is adapted to be securely engaged with the drive section of the surgical tool.

[0029] In particular, the surgical instrument is a surgical instrument (handpiece) with a fully integrated rotation mechanism.

[0030] Preferably, the counter coupling element (latch mechanism) has a resiliently mounted engagement element (latch body). Such a latch mechanism may latch into the bearing bush in a click-connect manner, thereby providing tactile and / or audible feedback for the complete insertion of the surgical tool into the surgical instrument. This means that the surgical tool is ready for use once the axial locking of the surgical tool has been achieved at the end of the coupling process.

[0031] More preferably, the distal and proximal instrument shafts can be bent towards each other. In particular, the distal and proximal instrument shafts can be chamfered at their opposite end faces and can be rotated relative to each other to achieve the angulation (bending) of the instrument shafts. Preferably, a gear train for rotating the distal instrument shaft relative to the proximal instrument shaft is arranged radially outward (in particular at a certain distance) from the tool shaft and / or drive shaft.

[0032] It is also advantageous if the drive shaft forms a distal centering receptacle, in particular a funnel-shaped one with a number of chamfered side walls. This further improves centering during insertion of the surgical tool (drive) into the surgical instrument (drive shaft). Preferably, the centering receptacle extends first radially outward from the hollow shaft and then proximally and radially outward in a funnel-shaped inclined manner. This ensures that the funnel-shaped part has a radial distance to the drive. The coupling area between the flexible part and the drive, which may be thicker compared to the drive, can thus be moved longitudinally in the area of ​​the centering receptacle (funnel-shaped part) without coming into contact with the funnel-shaped part. This allows for a compactification of the surgical tool and the surgical instrument in the longitudinal direction. In other words, the funnel-shaped portion is positioned and dimensioned to ensure sufficient space for the proximal engagement portion of the flexible portion to escape and to guide the surgical tool into the engagement receiving portion (shape receiving portion) of the drive shaft during the coupling process.

[0033] Preferably, the proximal instrument shaft section is provided with an axially extending space distal to the drive shaft, which ensures that the proximal coupling area of ​​the flexure to the drive section can be moved longitudinally. For this purpose, it is advantageous if a gear train (drive train) for bending the instrument shaft is provided radially outside (radially spaced from) the tool shaft (e.g. with a ring gear surrounding an axially extending space).

[0034] In particular, the drive shaft is disposed entirely within the proximal instrument shaft portion (e.g., the proximal handle portion) of the surgical instrument. Further, when the surgical tool is fully attached to the surgical instrument, the bearing portion may be disposed entirely within the distal instrument shaft portion and / or the drive portion may be disposed entirely within the proximal instrument shaft portion.

[0035] Advantageously, the drive shaft forms a longitudinally extending engagement receiver (in particular a contoured hollow shaft portion) for engaging with the (engagement portion of) the drive portion. Preferably, the length of the engagement receiver at least corresponds to (is greater than or equal to) the displacement distance of the proximal end of the flexible portion at maximum curvature. Preferably, the length of the engagement portion of the surgical tool and the length of the engagement receiver of the surgical instrument are complementary to each other such that they overlap even when the flexible portion is maximally or minimally bent.

[0036] It is also preferred that a distal pin is accommodated in the drive shaft in an axially movable and rotationally fixed manner, and that the distal pin is formed with a counter profile at its distal end for engaging with the profile of the surgical tool in a rotationally positioned manner. The counter profile is configured to engage with the profile so that it can (fully) engage with the profile only in one or more specific alignments. For example, the counter profile has a negative shape of the profile or has a number of contact surfaces distributed in the circumferential direction to contact the surface of the profile. When a rotationally symmetrical surgical tool is coupled to the instrument shaft, it is brought to the correct (rotational) position via a pin of such shape. In this case, it is particularly advantageous to hold the surgical tool on a bearing bush, since the tool shaft can rotate freely. The interaction (guidance) between the predetermined contour portion (profile portion) and the opposing predetermined contour portion (opposing profile portion) rotates (aligns) the surgical tool to the correct position. This aligns, for example, the engagement portion (having, for example, an outer shape of a hexagonal contour) to match (engage) with the engagement receiving portion (having, for example, an inner shape of a hexagonal contour). This simplifies the coupling process and positions the surgical tool (especially the funnel-shaped region) in the correct position. Therefore, misalignment or tilt between the engagement portion and the engagement receiving portion is significantly reduced.

[0037] The drive shaft may be provided with a spring element proximal to the distal pin, the spring element being configured to bias the distal pin in a distal direction, thereby ensuring that the distal pin (its distal end) is held within the funnel-shaped region or further distal when a surgical tool is not coupled to the surgical instrument, allowing early alignment of the engagement portion with respect to the engagement receiver. In this way, the spring element provides a guide for the distal pin. In particular, the spring element is a soft spring with a very low elastic modulus, which facilitates insertion of the surgical tool and further helps to avoid overloading the flexible portion. The spring element may be a mechanical spring, for example a coil spring, or may be, for example, a pneumatic spring.

[0038] Furthermore, preferably, the proximal side of the spring element is provided with a proximal pin accommodated (in particular in a rotationally fixed manner) in the drive shaft, which proximal pin supports the spring element from the proximal side. Further preferably, the distal pin, the proximal pin and the spring element are connected (for example welded, glued) to one another, in particular in a rotationally fixed manner, forming a coupling aid. The proximal and / or distal pin may have a tool holder (for example an adjustment slot) at its proximal end, which can be accessed, at least during assembly of the surgical instrument, for example using a screwdriver. The tool holder is provided for adjusting the rotational alignment of the counter predefined contour (counter profile) with respect to the engagement receptacle of the drive shaft or the engagement of the surgical tool.

[0039] In particular, the surgical instruments are hand-held instruments configured having a proximal gripping element (proximal handle portion) for grasping by a user with an instrument shaft extending distally from the proximal gripping element.

[0040] Alternatively or additionally, the problem on which the present invention is based is solved by a system comprising a surgical tool as described above and a surgical instrument as described above. [Brief description of the drawings]

[0041] The present invention will now be described with reference to preferred embodiments, which are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0042] [Figure 1] 1 shows a surgical tool according to a first embodiment of the invention on the bottom side and on the top side the surgical tool without the bearing bush installed. [Diagram 2] FIG. 2 is a detailed view of a flexible portion of the surgical tool shown in FIG. 1. [Diagram 3] 2 illustrates a bearing bushing for the surgical tool shown in FIG. 1; [Figure 4] 2 is a longitudinal cross-sectional view of the surgical tool shown in FIG. 1. [Diagram 5] 1 in a state where it is attached to a surgical instrument according to one embodiment of the present invention, and in the upper part of Fig. 5 in a state where it is bent at an angle, while in the lower part of Fig. 5 in a state where it is straight. [Figure 6] 6 shows a view of the proximal shaft of the surgical instrument shown in FIG. [Figure 7] 7 shows a docking aid for the surgical instrument shown in Fig. 5. The upper side of Fig. 7 shows the surgical tool shown in Fig. 1 in an unattached state, and the lower side of Fig. 7 shows the surgical tool in an attached state. [Figure 8] 6 illustrates a coupling process between the surgical tool shown in FIG. 1 and the surgical instrument shown in FIG. 5. [Figure 9] The adjustment of the joining auxiliary part shown in FIG. 7 is shown. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043] FIG. 1 shows a surgical tool 1 according to a first embodiment of the present invention. The surgical tool 1 has a tool tip (distal tool tip) 2 at its distal end. The tool tip (tool tip portion) 2 is, for example, a milling head (tool head portion). The tool shaft of the surgical tool 1 extends in a proximal direction from the tool tip 2. The tool shaft has a bearing portion (bearing portion) 3 connected (directly) to the tool tip 2, a flexible portion (flex portion) 4 connected (directly) to the proximal side of the bearing portion 3, and a driving portion (proximal driving portion) 5 connected (directly) to the proximal side of the flexible portion 4 and located on the most proximal side. The driving portion 5 has an engagement portion 6. The engagement portion 6 is formed in a shaft shape having a predetermined (for example, hexagonal) contour. The proximal end of the driving portion 5 forms a centering end 7. More specifically, the centering end 7 is a centering tip having a predetermined contour portion, for example, a pyramidal shape, extending in the longitudinal direction. As will be described in more detail below with reference to FIG.

[0044] The upper part (left side) of FIG. 1 shows the surgical tool 1 without the bearing bush 8 attached. As shown, the bearing portion 3 forms a portion with a reduced diameter (reduced diameter portion). The reduced diameter portion of the bearing portion 3 is bounded on the proximal side by a step of an expanded diameter portion of the bearing portion 3, and on the distal side by a radially outward protrusion at the proximal end of the tool tip 2. As shown in the lower part (right side) of FIG. 1, the bearing bush 8 is fixed to the reduced diameter portion of the bearing portion 3.

[0045] 2 shows a detailed view of the flexible portion 4 of the surgical tool 1 shown in FIG. 1. The flexible portion 4 has two radially stacked layers. The radially inner layer of the flexible portion 4 is formed by a plurality of fibers (strands) wound in a first winding direction around the longitudinal axis of the surgical tool 1. The radially outer layer of the flexible portion 4 is formed by a plurality of fibers (strands) wound in a second winding direction opposite to the first winding direction around the longitudinal axis of the surgical tool 1.

[0046] FIG. 3 shows a bearing bush 8 of the surgical tool 1 shown in FIG. 1. The bearing bush 8 has a housing 9 forming a radially outer wall (outer wall) of the bearing bush 8. A circumferential groove 10 is formed in the outer wall (outer surface) of the housing 9 as an engagement element or bearing coupling element. A bearing (e.g. a ball bearing (deep groove ball bearing)) 11 is mounted at each end of the housing 9. One (proximal) bearing 11 is fixedly coupled to the housing 9, and the other (distal) bearing 11 is floatingly mounted in the housing 9. A preloading element 12, for example having the form of a wave-shaped spring washer, is arranged between the housing shoulder of the housing 9 and the floatingly mounted (distal) bearing 11. The preloading element (biasing element) 12 preloads (biases) the corresponding bearing 11 (in particular its outer ring) axially outward (towards the tool tip in the mounted state). Between the two bearings 11, in particular adjacent to the inner ring of the bearing 11, a spacer bush 13 is provided. The spacer bushing 13 axially positions the two bearings 11 relative to each other. On the opposite side of the spacer bushing 13 (outside the bearing bushing 8) to the bearing 11 located on the distal side of the surgical tool 1, a cover disc 14 is attached. The cover disc 14 covers and / or seals the gap between the inner and outer rings of the bearing 11.

[0047] Fig. 4 is a longitudinal cross-sectional view (cross-sectional view along the longitudinal direction) of the surgical tool 1 shown in Fig. 1. As shown in Fig. 4, one end of the flexible part 4 is accommodated (engaged) in a receiving part (recess) formed at the proximal end of the bearing part 3, and the other end of the flexible part 4 is accommodated (engaged) in a receiving part (recess) formed at the distal end of the driving part 5. Furthermore, the bearing bush 8 is fixed at a predetermined position in the axial direction by being sandwiched between a shoulder part formed at the tool tip 2 so as to expand radially outward and a shoulder part formed at the bearing part 3 so as to expand radially outward.

[0048] FIG. 5 shows the surgical tool 1 of FIG. 1 attached to a surgical instrument 15 according to an embodiment of the present invention. The upper part of FIG. 5 shows the surgical tool 1 in a straight state, and the lower part of FIG. 5 shows the surgical tool 1 bent at an angle. The surgical instrument 15 has a proximal shaft portion (proximal instrument shaft portion) 16 and a distal shaft portion (distal instrument shaft portion) 17 as an instrument shaft. The opposing end surfaces of the proximal shaft portion 16 and the distal shaft portion 17 extend obliquely with respect to the longitudinal axis, and are connected to each other via a rotation mechanism that rotates the proximal shaft portion 16 and the distal shaft portion 17 relative to each other. As a result, the proximal shaft portion 16 and the distal shaft portion 17 can be in a form (position) bent at an angle relative to each other, for example, as shown in the lower diagram of FIG. 5.

[0049] The surgical tool 1 is fixed in its axial position relative to the surgical instrument 15 via the bearing bush 8. The bearing bush 8 or the proximal bearing 11 forms a stopper surface at its proximal end surface. The stopper surface allows the bearing bush 8 or the proximal bearing 11 to contact the housing of the distal shaft portion 17. Furthermore, the housing of the distal shaft portion 17 accommodates a latch mechanism having a spring-loaded (elastically biased) slider (latch slider) 18. The spring-loaded slider 18 applies a compressive stress (biasing force) to the latch body 19 in the radially inward direction in order to engage with the engagement element (circumferential groove 10 as a bearing coupling element) of the bearing bush 8. The engagement of the latch body 19 with the engagement element (circumferential groove 10 as a bearing coupling element) of the bearing bush 8 fixes the position of the bearing bush 8 relative to the distal shaft portion 17 so that displacement in the distal direction is restricted.

[0050] The flexible part 4 extends from the bearing part 3 to the driving part 5 through the distal shaft part 17 and the proximal shaft part 16. The flexible part 4 follows the angle formed between the proximal shaft part 16 and the distal shaft part 17, if necessary (see the lower part of FIG. 5). The proximal end of the flexible part 4 is connected to the driving part 5 in an area of ​​axially extending space (axial space) (for example in a ring gear of a rotating mechanism). The driving part 5 (in particular its engagement part 6) is received in an engagement receiving part 21 of the drive shaft 20 in a form-fitting and axially displaceable manner. The engagement receiving part 21 is configured, for example in the form of a hexagonal hole, so as to be complementary to the engagement part 6.

[0051] The distal end of the drive shaft 20 is formed with a funnel-shaped centering receiver 22. The centering receiver 22 is enlarged to provide a radial distance between the distal end of the engagement receiver 21 and the drive part 5, thereby allowing the enlarged coupling area connecting the flexible part 4 and the drive part 5 to move within the centering receiver 22. Furthermore, the centering receiver 22 is enlarged radially outward in the distal direction, which aids in the insertion of the drive part 5 during assembly of the surgical tool 1.

[0052] 5, the axial position of the surgical tool 1 within the distal shaft portion 17 remains constant as the surgical instrument 15 is bent. However, bending or radial slippage of the flexible portion 4 during bending causes the proximal end of the surgical tool 1 to move axially. In particular, the coupling region of the flexible portion 4 and the driving portion 5 moves axially within the centering receptacle 22 and said axial space, and the engagement portion 6 of the driving portion 5 moves axially within the engagement receptacle 21 of the drive shaft 20.

[0053] Figure 6 shows an enlarged view of the proximal shaft portion 16 of the surgical instrument shown in Figure 5 without the surgical tool 1 attached, making visible in Figure 6 the engagement receptacle 21 of the drive shaft 20, which is exemplarily configured as a hexagonal socket.

[0054] FIG. 7 shows the docking aid of the surgical instrument 15 shown in FIG. 5. The upper part of FIG. 7 shows the surgical tool 1 shown in FIG. 1 in an unattached state, and the lower part of FIG. 7 shows the surgical tool 1 attached. The docking aid has a distal pin 23, a spring element 24 attached or rotatably fixed to the proximal end of the distal pin 23, and a proximal pin 25 attached or rotatably fixed to the proximal end of the spring element 24. The distal pin 23, the proximal pin 25, and the spring element 24 are housed in a drive shaft 20. The drive shaft 20 may be composed of several parts. The distal pin 23 is arranged rotatably and axially displaceably relative to the drive shaft 20. Preferably, the proximal pin 25 and the spring element 24 are also rotatably arranged in the drive shaft 20. The spring element 24 biases the distal pin 23 in the distal direction. Thus, when the surgical tool 1 is not attached and the spring element 24 is not compressed, the distal end of the distal pin 23 protrudes from the drive shaft 20, as will be described in more detail below, as shown in the top view of Figure 7. When the surgical tool 1 is attached, the distal pin 23 is pushed back proximally by the drive portion 5 of the tool 1 and the spring element 24 is compressed, as shown in the bottom view of Figure 7.

[0055] FIG. 8 shows the coupling process of the surgical tool 1 shown in FIG. 1 and the surgical instrument 15 shown in FIG. 5. In FIG. 8A, the tool shaft of the surgical tool is inserted into the instrument shaft of the surgical instrument 15, but the bearing bush 8 is still outside the instrument shaft. The centering end 7 of the drive part 5 is introduced into the funnel-shaped centering receiver 22, and is centered by the centering receiver 22 and guided into the engagement receiver 21. The distal end of the distal pin 23 is placed at the entrance of the engagement receiver 21. The distal end of the distal pin 23 forms a counter predetermined profile 26 for receiving and aligning the centering end 7 (predetermined profile) of the drive part 5. The counter predetermined profile is aligned with the engagement receiver 21 of the drive shaft 20. As a result, when the predetermined contour portion (centering end portion 7) enters the opposing predetermined contour portion 26, as shown in FIG. 8B, the engagement portion 6 of the drive portion 5 is aligned with the engagement receiving portion 21 of the drive shaft 20.

[0056] Next, as shown in FIG. 8C, the driving part 5 pushes the distal pin 23 in the proximal direction, and the engagement part 6 of the driving part 5 of the surgical tool 1 is pressed into the engagement receptacle 21 of the driving shaft 20 of the surgical instrument 15. At the same time, the bearing bush 8 slides into the distal shaft part 17 of the surgical instrument 15. In FIG. 8D, the surgical tool 2 is finally and completely inserted into the surgical instrument 15. The bearing bush 8 contacts the housing of the distal shaft part 17 in the proximal direction, and the latch body 19 engages with the engagement element (circumferential groove 10 as a bearing coupling element) of the bearing bush 8. In this way, the surgical tool 1 is completely attached to the surgical instrument 15.

[0057] FIG. 9 shows the adjustment of the coupling aid shown in FIG. 7. In more detail, FIG. 9 shows the proximal end of the proximal pin 25. The proximal end of the proximal pin 25 is provided with a mating (e.g. slotted) tool holder 27. An adjustment tool 28 may be inserted into the tool holder in order to align the proximal pin 25 with the spring element 24 and the distal pin 23 (more specifically, their opposing contoured portions) connected to the spring element 24 in a rotationally fixed manner (without relative rotation) in the engagement receiver (engagement holder) 21 of the drive shaft 20 during assembly of the surgical instrument. If necessary, a tool holder for adjusting the distal pin 23 may also be provided directly on the distal pin 23. [Explanation of symbols]

[0058] 1 Surgical tools 2 Tool Tip (Tool Head) 3 Bearing part 4 Flexible part 5 Drive unit 6 Engagement part 7 Centering end (centering tip) (predetermined contour portion) 8 Bearing bush 9 Bearing bush housing 10 Circumferential groove (bearing coupling element) (engagement element) 11 Bearings (ball bearings) 12 Preload element (wave spring washer) 13 Spacer bush 14 Cover Disc 15 Surgical instruments 16 Proximal shaft portion (proximal instrument shaft portion) 17 Distal shaft portion (distal instrument shaft portion) 18 Latch slider (latch mechanism) 19 Latch body (elastically attached engagement element) (latch mechanism) 20 Drive shaft 21 Engagement receiving portion 22 Centering receiving part 23 Distal Pin 24 Spring elements 25 Proximal Pin 26 Opposite specified contour portion 27 Tool holder

Claims

1. A surgical tool (1) configured to be inserted into an instrument shaft (16, 17) of a surgical instrument (15), comprising: A distal tool tip (2); a tool shaft (3, 4, 5) extending proximally from the distal tool tip (2), the tool shaft having a bearing portion (3) located distally and a drive portion (5) located proximally of the bearing portion (3), the drive portion (5) being configured to engage with a drive shaft (20) of the surgical instrument (15); a bearing bush (8) attached in an axially fixed manner to the bearing portion (3) when not inserted in the surgical instrument (15), the bearing bush (8) having a bearing coupling element (10) for detachably coupling to the instrument shaft (16, 17) of the surgical instrument (15); A surgical tool comprising:

2. The tool shaft (3, 4, 5) further includes a flexible portion (4) between the bearing portion (3) and the drive portion (5), the flexible portion (4) being flexible in bending and having torsional rigidity. The surgical tool of claim 1 .

3. The bearing bush (8) has a proximal end face that constitutes a contact surface with the instrument shaft (16, 17). A surgical tool according to claim 1 or claim 2.

4. The drive part (5) has at least one axially extending engagement part (6), in particular a contoured shaft part, A surgical tool according to any one of claims 1 to 3.

5. the length of the engagement portion (6) is equal to or greater than the maximum axial displacement distance of the proximal end of the tool shaft (3, 4, 5) at the maximum curvature of the tool shaft (3, 4, 5); The surgical tool of claim 4.

6. The drive part (5) has a proximal centering end (7), in particular a centering tip having a number of chamfered side walls. A surgical tool according to any one of claims 1 to 5.

7. The centering tip (7) constitutes a predetermined contour, in particular having a pyramidal contour, the contoured portion is adapted to engage an opposing contoured portion (26) of the surgical instrument (15), in particular a distal pin (23), in a rotationally positioned manner; The surgical tool of claim 6.

8. an instrument shaft (16, 17) opening in a distal direction and adapted to receive a surgical tool (1) according to any one of claims 1 to 7; a distal instrument shaft portion (17) of the instrument shaft is provided with a resiliently biased or prestressable latch mechanism (18, 19) for releasably coupling to the bearing coupling element (10) of the surgical tool (1); a proximal instrument shaft portion (16) of the instrument shaft having a drive shaft (20) configured to engage the drive portion (5) of the surgical tool (1); Surgical instruments.

9. The drive shaft (20) has a distal centering receptacle (22), which is in particular funnel-shaped with a number of chamfered side walls.

9. The surgical instrument of claim 8.

10. the proximal instrument shaft portion (16) defines an axially extending space distal to the drive shaft (20); A surgical instrument according to claim 8 or claim 9.

11. the drive shaft (20) has a longitudinally extending engagement receiving portion (21) for engaging with the drive portion (5), in particular a contoured hollow shaft portion; A surgical instrument according to any one of claims 8 to 10.

12. A distal pin (23) is housed in the drive shaft (20) in an axially movable and rotationally fixed manner; the distal pin (23) having an opposing contoured portion (26) at its distal end for engaging a contoured portion (7) of the surgical tool (1) in a rotationally positioned manner; A surgical instrument according to any one of claims 8 to 11.

13. The drive shaft (20) is provided with a spring element (24) proximal to the distal pin (23), The spring element (24) is configured to bias the distal pin (23) in a distal direction. A surgical instrument according to any one of claims 8 to 12.

14. The spring element (24) is provided on its proximal side with a proximal pin (25) housed within the drive shaft (20); The proximal pin (25) is rotationally fixedly connected to the distal pin (23); a tool holder (27) is provided at the proximal end of the proximal pin (25) for adjusting the rotational alignment of the opposing contoured portion (26) relative to the drive shaft (20); A surgical instrument according to any one of claims 8 to 13.

15. A surgical tool (1) according to any one of claims 1 to 7, A surgical instrument (15) according to any one of claims 8 to 14, A system comprising:

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