Device for carrying out a resection in a femur or lower leg bone

Abstract

The invention relates to a device (2) for carrying out a resection in a femur or lower leg bone, in particular for carrying out a femur resection during the introduction of a hip joint prosthesis, the device comprising a rasp tool (4) which can be introduced into the femur and has a mechanical interface (14), protruding to the outside in the introduced state, for the coupling of a handling tool for the rasp tool, characterized by a motor-drivable face milling tool (8) having a milling head (20) with end-face cutting edges (22), and furthermore characterized in that an elongate guide rod (6) which is at least 5 cm in length is couplable to the interface (14) and forms a guide axis (18) for the face milling tool (8), in that the face milling tool (8) has a sleeve-like shank portion (24) which adjoins the milling head (20) and by means of which the face milling tool (8) can be plugged onto the guide rod (6) and is thereby guided axially and rotationally, and in that the face milling tool (8) can be driven so as to not rotate endlessly but rather oscillate rotationally back and forth about the guide axis (18) by at most + / - 20°, and for this purpose has, on the end of the sleeve-like shank portion (24) which is remote from the milling head (20), an interface (26) for connection to a motor drive device.

Description

[0001] Title: Device for performing a resection in a

[0002] thigh bone or lower leg bone

[0003] Description

[0004] The present invention relates to a device for performing a resection on a femur or tibia, in particular for performing a femur resection during the insertion of a hip joint prosthesis, comprising a rasping tool that can be inserted into the femur with a [missing element] inserted into the [missing element].

[0005] externally projecting mechanical interface for coupling a handling tool for the rasp tool.

[0006] EP 0 548 485 Bl shows a hand-operated device with a rasping tool that can be inserted into the femur and a hand-guided and hand-operated face milling tool that can be attached to it via an adapter. The face milling tool has a milling head with end-face cutting edges and a handle for performing a rotary oscillating back-and-forth movement of the face milling tool. The device is complex in design and, due to the inherent play in the components resulting from the hand-operated design, does not allow for sufficient machining accuracy.

[0007] The present invention is based on the objective of providing a device of the type mentioned above, by means of which, starting from a rasping tool inserted into the femur, a resection of the bone in the area next to or around the inserted rasping tool can be carried out in a precise and simple manner, whereby a disturbance-free and time-minimized executability in the surgical situation is of particular importance.

[0008] This problem is solved by a device of the type mentioned above, which is characterized by a motor-driven face milling tool with a milling head with face-facing cutting edges, and is further characterized in that an elongated guide rod, at least 3 cm long, can be coupled to the interface of the rasping tool, which forms a guide axis for the face milling tool, and that the face milling tool has a sleeve-shaped shank section adjoining the milling head, by means of which the face milling tool can be mounted on the guide rod and thereby guided axially and rotationally, and that the face milling tool is not driven in an endless rotation but in a rotationally oscillating manner about the guide axis by a maximum of + / - 20° back and forth, and for this purpose has an interface at the end of the sleeve-shaped shank section facing away from the milling head for connection to a motor drive device.While previously the areas around a rasp tool inserted into the bone were processed using separate, rotary-driven milling tools, particularly face milling tools or oscillating saws, to produce a flat resection plane, the present invention proposes to provide a highly efficient guide for an oscillating face milling tool. In this system, the aforementioned guide rod is coupled to the mechanical interface of the rasp tool, which is inserted into the femur as a template component, acting as a guide axis for the face milling tool. The considerable length of the guide rod and the sleeve-shaped shank section of the face milling tool allows for a virtually backlash-free arrangement of the motor-driven face milling tool during surgery, thus enabling very precise guidance and machining accuracy.The surgeon performing the procedure simply needs to slide the motorized drive device with the attached face milling tool onto the guide rod, then actuate the rotary oscillating drive and pivot the drive device and thus the face milling tool slowly and evenly back and forth around the guide axis under axial pressure, depending on the circumferential extent of the resection plane to be formed, so that a continuous flat resection surface is produced.

[0009] It is advantageous if the face milling tool can be driven in a reciprocating rotary oscillation of at most + / - 15°, in particular at most + / - 12°, in particular at most + / - 10°, in particular at most + / - 8°, in particular at most + / - 6°, in particular at most + / - 5°, in particular at most + / - 4°, in particular at most + / - 3°, in particular at most + / - 2°. It is particularly advantageous if the rotary oscillation drive is only ± a few degrees, as this results in smoother running and lower counterforces generated during milling. In such cases, the oscillating movement is perceived more as a back-and-forth vibrating movement, and the device as a whole can be held and guided more smoothly and therefore more comfortably by the operator.However, depending on the circumference of the milling head and the face milling tool, the drive unit with the face milling tool must be pivoted back and forth around the guide axis to a greater or lesser extent in order to produce a completely flat surface of the desired circumference. If the circumference of the milling head is larger and / or the rotary oscillating movement occurs over a larger angular range, and consequently a larger area is covered by the milling operation, the operator must pivot the drive unit with the face milling tool back and forth less, and vice versa.

[0010] Furthermore, it proves advantageous if the guide rod is at least 4 cm, in particular at least 5 cm, in particular at least 6 cm, in particular at least 7 cm, in particular at least 8 cm, in particular at least 10 cm, in particular at least 12 cm, and further, in particular, at most 20 cm long. This allows the guide length of the face milling tool to be increased compared to the rasp tool inserted into the bone, with the longitudinal extent of the sleeve-shaped shaft section being dimensioned accordingly so that the entire length of the guide rod can be used as a guide.

[0011] To enable the face milling tool to be used even with respect to a rasp tool protruding from the femur or protruding wall sections of a rasp tool, it proves advantageous if the face milling tool is designed with a hat-shaped or bell-shaped segment in the area of ​​the milling head. This allows the hat-shaped or bell-shaped segment to essentially accommodate or cover a free proximal end of the rasp tool without colliding with it during machining.

[0012] Similarly, it proves advantageous if the face milling tool is designed with a semi-circular face. This semi-circular face, in which a circular segment is recessed, allows the face cutting edges to be arranged radially spaced from the center of the oscillation or guide axis. The radial length or extent of the face cutting edges can vary circumferentially.

[0013] Furthermore, it proves advantageous if the semi-annular disc-shaped end face is formed by a rim area of ​​a hat-shaped or bell-shaped segment of the face milling tool. In this way, an effective design can be achieved, in which, on the one hand, the face cutting edges can be positioned where they are needed, and on the other hand, a material-free installation space is created for the execution of the rotary-oscillating drive movement of the face milling tool. In addition, the wall thickness of the milling head can be reduced.

[0014] It is further proposed that the semi-annular disc-shaped end face extends circumferentially over at least 100°, in particular over at least 110°, in particular over at least 120°, in particular over at least 130°, in particular over at least 140°, in particular over at least 150°, in particular over at least 160°, and in particular over a maximum of 230°, in particular over a maximum of 220°, in particular over a maximum of 210°, in particular over a maximum of 200°, and in particular over a maximum of 190°. Again, there is a relationship between the stroke of the rotary oscillating drive (expressed in ± degrees) and the circumferential extent of the semi-annular disc-shaped end face of the milling head of the face milling tool, provided that the rasping tool inserted into the bone does not permit a complete (360°) rotation of the face milling tool, which is typically the case.

[0015] It is further advantageous if the face milling tool has a material-free circular segment extending from the axis of rotation with a circular segment angle of at least 40°, in particular at least 50°, in particular at least 60°, in particular at least 70°, in particular at least 80°, in particular at least 90°, in particular at least 100°, in particular at most 180°, in particular at most 170°, in particular at most 160°, in particular at most 150°, in particular at most 140°, in particular at most 130°, in particular at most 120°. A material-free circular segment of approximately 110° to 140° is considered particularly preferred.

[0016] The face milling tool can be further designed to have a continuously flat face or to taper radially outwards from a flat face in a conical and / or curved manner. In the latter case, cutting edges with potentially different designs or geometric inclinations to the surface of the face can also be provided in the area of ​​the conical or curved sections of the face.

[0017] It can be further advantageous if the sleeve-shaped shank section of the face milling tool has a fenestration at a milling head end and / or at a drive-side end, allowing a view of the guide rod, and is particularly well-shaped in this area. This allows the depth of the milling or machining already performed to be determined by observing the position of the guide rod, especially any markings on the guide rod.

[0018] Furthermore, it proves advantageous if the interface for connection to the drive device has a plate that can be inserted orthogonally to the guide axis into a sliding seat mount of the drive device. The sliding seat mount of the drive device can be driven as a whole in a rotary oscillating motion, with the respective axes of rotation of the drive device and the face milling tool being aligned when the

[0019] The face milling tool is inserted into the sliding seat mount and brought into the intended drive connection there.

[0020] Furthermore, it proves advantageous if the plate can be locked into the sliding seat, in particular if it has an opening or recess into which an engagement projection or a pawl of the drive device can engage. In this way, a drive connection can be established in a quasi-force-guided manner as intended.

[0021] Furthermore, it proves advantageous if the interface of the face milling tool for connection to the drive device has a rotationally fixed base body formed with the sleeve-shaped shank section and extending orthogonally to the guide axis or axis of rotation, in particular a cuboid-shaped base body, and that a wall section rises from the base body, on which the plate is held at a distance from the base body and extends from there parallel to the base body.

[0022] According to the invention, it is further proposed to use a drive device for a typical oscillating saw, which is always present in a typical operating room situation and is also commonly used in the preparations for hip joint prosthesis insertion discussed here, for the rotary oscillating reciprocating drive of the face milling tool. In such oscillating saws, a drive device typically has a rotary reciprocating drive, which is converted at a tool attachment point or interface of the drive device for the saw blade into a reciprocating movement of the saw blade in a plane orthogonal to the rotary drive of the drive device.

[0023] In view of this, a system or kit or array having the features of one or more of claims 14-18 is also considered to be independently inventive.

[0024] In this way, the same drive device can be used in the operating room situation both to drive the saw blade of an oscillating saw and to drive the face milling tool in question. In particular, protection is claimed for such a system, kit, or array with a device according to one or more of claims 1 to 13.

[0025] Further features, details and advantages of the invention will become apparent from the attached patent claims and from the graphic representation and subsequent description of a preferred embodiment of the invention.

[0026] The drawing shows:

[0027] Figure 1 shows a perspective view of the device according to the invention with its components in their interacting operating position;

[0028] Figures 2a-c show a side view and two perspective views of the device according to the invention, wherein its components are shown individually spaced axially apart from each other; Figures 3a, b show detailed views of the device according to Figure 1;

[0029] Figures 4a-g show different views of a face milling tool of the device according to Figures 1 to 3;

[0030] Figures 5a-c show different representations of a guide rod of the device according to Figure 1; and

[0031] Figures 6a-e illustrate a system, kit or array consisting of a drive device, a saw blade and a face milling tool.

[0032] Figures 1 to 3 show a device 2 according to the invention. The device comprises a rasping tool 4 that can be inserted into the femur, as well as a guide rod 6 and a face milling tool 8. The rasping tool 4 is flat and slightly wedge-shaped in a manner known per se and has rasping edges 12 extending transversely or obliquely to an approximately indicated insertion direction 10 on its four surfaces. Using this rasping tool 4, a medullary canal of the femur is hollowed out, and the rasping tool 4 is inserted into the femur in a manner known per se, simulating in this situation the stem of the actual implant, which is to be inserted later. The rasping tool 4 includes a mechanical interface 14 for coupling a handling tool (not shown) for holding, guiding, and inserting the rasping tool 4.After the rasping tool 4 is inserted into the bone, the handling tool (not shown) is removed from the interface 14 and the guide rod 6 is attached to the interface 14 instead; in the simplest case, it can be mounted on the interface 14 in its longitudinal direction 16, which in the example shown is formed by a pin with a cylindrical outer surface. The guide rod 6 forms a longitudinal guide and thus a guide axis 18 for the face milling tool 8.

[0033] In the exemplary case shown, the face milling tool 8 is made of three parts, which are welded together at their respective joints (see Figures 4a-g). These three parts comprise a milling head, designated overall by reference numeral 20, with face cutting edges 22, and a sleeve-shaped shank section 24 adjoining it, and an interface 26 provided at the end of the sleeve-shaped shank section 24 facing away from the milling head 20 for connecting the face milling tool 8 to a motor drive device (not shown).

[0034] The face milling tool 8 is not designed for continuous rotary drive, but rather can be driven in a rotary oscillation about the guide axis 18, moving back and forth by a few degrees. Its milling head 20 comprises a hat-shaped or bell-shaped segment 28 with a semi-annular disc-shaped end face 30, on which the end-face cutting edges 22 are formed. It can be seen that the semi-annular disc-shaped end face 30 is formed by a rim region 32 of the hat- or bell-shaped segment 28. In this way, the semi-annular disc-shaped end face 30 is extended radially outwards without having to increase the wall thickness of the hat-shaped segment 28.Furthermore, it can be seen that the semi-annular disc-shaped end face 30 and, correspondingly, the hat-shaped segment 28 extend circumferentially only over approximately 220°, so that a material-free circular segment 34 with a circular segment angle 35 of approximately 140° (see Fig. 4g) is formed. In this way, the hat-shaped or bell-shaped segment 28 or the milling head 20 is able to accommodate a proximal end region 36 of the rasp tool 4 protruding from the bone within the hat or bell shape, while still allowing a rotary-oscillating drive of the end milling tool 8 to form resection areas around the rasp tool 4 protruding from the bone as required.

[0035] Figures 2 and 4 also show a recess or fenestration 38 on a milling head soapy end region of the sleeve-shaped shank section 24 and a further recess or fenestration 40 on a drive-side end region of the sleeve-shaped shank section 24, which allow a view of the guide rod 6 when the face milling tool with its sleeve-shaped shank section 24 is placed on the guide rod 6.

[0036] Furthermore, the exemplary design of the interface 26 can be seen in Figures 4a-g. It comprises a plate 42, which extends in a plane orthogonal to the guide axis 18 and can also be inserted orthogonally to the guide axis 18 (see arrow 44 in Figure 4c) into a sliding seat receptacle 58 of the drive device 50 shown in Figure 6 (shown for the first time in Figure 6). The plate 42 can be locked in the sliding seat receptacle 58 and includes an engagement opening 46 into which an engagement projection 62 or a pawl of the drive device 50 can engage (Figures 6c-e). In this way, the sleeve-shaped shank section 24, and thus the entire face milling tool 8, can be coupled rotationally fixed to an interface 54 of the drive device 50 (to be explained later) and thus rotated about the guide axis 18. The rotational axis 68 is driven in a rotating oscillating back-and-forth motion by the drive device 50.

[0037] Figures 6a and 6b show a motorized drive device 50 with a rotary-oscillating reciprocating drive about an axis 52 and with a corresponding rotary-oscillating interface 54 for attaching a saw blade 56, which can also be driven in a rotary-oscillating reciprocating motion in a plane orthogonal to the axis 52. Furthermore, the motorized drive device 50 and its interface 54 are also designed for attaching and driving a rotary-oscillating reciprocating milling tool, in particular a face milling tool 8 of the type described above. For this purpose, the interface 54 of the drive device includes a sliding seat 58 into which the saw blade 56 can be inserted with a plate-shaped end and preferably locked in place.For this purpose, the plate-shaped end of the saw blade 56 has an opening 60 into which an engagement projection 62 of the interface 54 of the drive device 50 can engage and, if necessary, be retracted so that the saw blade 56 can be removed again. Retracting the engagement projection 62 to unlock the saw blade can be achieved, for example, by pressing a finger on an actuating button 63 (Figure 6c) at the interface 54 of the drive device 50. Figures 6c-e illustrate the attachment of a milling tool, and in particular the face milling tool 8 described above, via its interface 26 to the interface 54 of the motorized drive device 50. It is essential that the axis of rotation 68 of the milling tool is aligned with the axis 52 of the drive device 50.For this purpose, the interface 26 of the face milling tool 8 has an exemplary cuboid-shaped base body 64, which is rotationally fixed to the sleeve-shaped shank section 24 and extends orthogonally to it. A wall section 66 rises from the base body 64, on which the previously mentioned plate 42 is held at a distance from the base body 64 and extends from there parallel to the base body 64. The engagement opening 46 is formed in the plate 42, into which the engagement projection 62 of the interface 54 of the drive device 50 can engage in order to couple the milling tool 8 to the drive device 50 in a rotationally fixed manner. This state is shown in Figure 6e. Figures 6d and e also show the rasp tool 4 with guide rod 6, on which the face milling tool 8 with its sleeve-shaped shank section 24 is mounted when resection surfaces are machined using the face milling tool 8.

Claims

Patent claims 1. Device (2) for performing a resection on a femur or tibia, in particular for performing a femur resection during the insertion of a hip prosthesis, comprising a rasping tool (4) that can be inserted into the femur and has a mechanical interface (14) projecting outwards in the inserted state for coupling a handling tool for the rasping tool, characterized by a motor-driven face milling tool (8) with a milling head (20) with face cutting edges (22), and further characterized in that an elongated guide rod (6) at least 3 cm long can be coupled to the interface (14), which forms a guide axis (18) for the face milling tool (8), and that the face milling tool (8) has a sleeve-shaped shaft section (24) adjoining the milling head (20),by means of which the face milling tool (8) can be mounted on the guide rod (6) and thereby guided axially and rotationally, and that the face milling tool (8) is not driven in an endless rotation but in a rotationally oscillating manner about the guide axis (18) by a maximum of + / - 20° back and forth, and for this purpose at the end of the sleeve-shaped shaft section facing away from the milling head (20), (24) has an interface (26) for connection to a motor drive device (50).

2. Device (2) according to claim 1, characterized in that the face milling tool (8) can be driven rotaryally oscillating by at most + / - 15°, in particular by at most + / - 12°, in particular by at most + / - 10°, in particular by at most + / - 8°, in particular by at most + / - 6°, in particular by at most + / - 5°, in particular by at most + / - 4°, in particular by at most + / - 3°, in particular by at most + / - 2°.

3. Device (2) according to claim 1 or 2, characterized in that the guide rod (6) is at least 4 cm, in particular at least 5 cm, in particular at least 6 cm, in particular at least 7 cm, in particular at least 8 cm, in particular at least 10 cm, in particular at least 12 cm and further in particular at most 20 cm long.

4. Device (2) according to one or more of the preceding claims, characterized in that the face milling tool (8) is designed with a hat-shaped or bell-shaped segment (28) in the area of ​​the milling head (20).

5. Device (2) according to one or more of the preceding claims, characterized in that the face milling tool (8) is designed with a partially annular disc-shaped face surface (30).

6. Device (2) according to claim 5, characterized in that the partially annular disc-shaped end face (30) of a rim area (32) of a hat-shaped or bell-shaped segment (28) of the face milling tool (8) is formed.

7. Device (2) according to claim 5 or 6, characterized in that the semi-annular disc-shaped end face (30) extends in the circumferential direction over at least 100°, in particular over at least 110°, in particular over at least 120°, in particular over at least 130°, in particular over at least 140°, in particular over at least 150°, in particular over at least 160° and in particular over at most 230°, in particular over at most 220°, in particular over at most 210°, in particular over at most 200°, in particular over at most 190°.

8. Device (2) according to one or more of the preceding claims, characterized in that the face milling tool (8) has a material-free circular segment area (34) extending from the axis of rotation with a circular segment angle (35) of at least 40°, in particular at least 50°, in particular at least 60°, in particular at least 70°, in particular at least 80°, in particular at least 90°, in particular at least 100°, in particular at most 180°, in particular at most 170°, in particular at most 160°, in particular at most 150°, in particular at most 140°, in particular at most 130°, in particular at most 120°.

9. Device (2) according to one or more of the preceding claims, characterized in that the The face milling tool (8) has a continuously flat face or is designed to taper radially outwards from a flat face in a conical and / or curved manner.

10. Device (2) according to one or more of the preceding claims, characterized in that the sleeve-shaped shaft section (24) has a fenestration (38, 40) at a milling head soapy end and / or at a drive-side end allowing inspection of the guide rod (6) and is in particular essentially semi-shell-shaped there.

11. Device (2) according to one or more of the preceding claims, characterized in that the interface (26) for connection to the drive device is orthogonal to the guide axis (18) has a sliding plate (42) into a sliding seat receptacle (58) of the drive device (50). (The sliding seat mount of the drive device can be driven as a whole in a rotary oscillating back-and-forth motion.) 12. Device (2) according to claim 11, characterized in that the plate (42) can be locked into the sliding seat receptacle (58), in particular having an engagement opening (46) or an engagement recess into which an engagement projection (62) or a latch of the drive device (50) can engage.

13. Device (2) according to claim 11 or 12, characterized in that the interface (26) of the face milling tool (8) for connection to the drive device (50) has a base body (64) which is rotationally fixed to the sleeve-shaped shaft section (24) and extends orthogonally to the guide axis (18) or axis of rotation (68), in particular a cuboid base body, and that a wall section (66) rises from the base body (64), on which the plate (42) is held at a distance from the base body (64) and extends from there parallel to the base body (64).

14. System, kit or array comprising a motorized drive device (50) with a rotary oscillating reciprocating drive about an axis (52) and with a corresponding rotary oscillating reciprocating interface (54) for attaching a saw blade (56) which is also rotary oscillating reciprocating in a plane orthogonal to the axis (52) and for attaching a rotary oscillating reciprocating face milling tool (8) whose axis of rotation is aligned with or parallel to the axis (52) of the drive device (50), and further comprising such a rotary oscillating reciprocating saw blade (56) and such a rotary oscillating reciprocating face milling tool (8).

15. System, kit or array according to claim 14, characterized in that the face milling tool (8) has a sleeve-shaped shank section (24) and a The interface (26) has a non-rotating interface for connecting the face milling tool (8) to the interface (54) of the drive device (50) and the interface (26) has a plate (42) that can be inserted orthogonally to the axis of rotation of the face milling tool (8) into a sliding seat mount (58) on the drive device (50).

16. System, kit or array according to claim 15, characterized in that the plate (42) can be locked into the sliding seat receptacle (58), in particular having an engagement opening (46) or an engagement recess into which an engagement projection (62) or a latch of the drive device (50) can engage.

17. System, kit or array according to claim 15 or 16, characterized in that the interface (26) of the face milling tool (8) for connection to the drive device (50) has a base body (64) which is rotationally fixed to the sleeve-shaped shaft section (24) and extends orthogonally to the guide axis (18), in particular a cuboid base body (64), and that a wall section (66) rises from the base body (64), on which the plate (42) is held at a distance from the base body (64) and extends from there parallel to the base body (64).

18. System, kit or array according to one or more of claims 14-17, comprising a device (2) according to one or more of claims 1-13.

Images