DE29703857U1 - Surgical instrument - Google Patents

Description

A 53772 u AESCULAP AG

u - 223 Am Aesculap-Platz

17 February 1997 78532 Tuttlingen

SURGICAL INSTRUMENT

The invention relates to a surgical instrument for releasing the clamping fit of a joint insert in a joint socket.

In joint sockets, for example in hip joint sockets, joint inserts are often held by a clamping cone connection. In order to be able to remove such joint inserts from the joint socket, it is either necessary to destroy the joint inserts or to provide special devices on the joint socket that enable the joint insert to be ejected from the joint socket. For example, DE 295 16 473 Ul describes a screw arrangement on the joint socket with which the joint insert can be pressed out of the joint socket. However, this makes it necessary to design the joint socket accordingly and to leave a hole in the joint insert.

It is the object of the invention to provide a surgical instrument with the aid of which the clamping connection between the joint insert and the joint socket can be released without special structural designs of the joint insert and the joint socket being necessary.

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This object is achieved according to the invention by a surgical instrument of the generic type, which is characterized by at least two supports that can be placed on the edge of the joint socket and are connected to a striking surface that is arranged centrally to the joint socket and points away from the open side of the joint socket.

These supports are placed on the edge of the joint socket and blows are transferred from the striking surface to the joint socket via these supports. These blows can be carried out manually with a hammer or with a pneumatic or electrically operated impact tool of a known design.

It is known that conical clamp connections can come loose under the effect of such blows, and this is precisely what can be observed when using the surgical instrument described. It is advantageous that at least two supports are provided and that the forces are applied centrally, so that there is no danger of the joint socket tipping over due to one-sided impact and giving way under the blows.

It is particularly advantageous if three supports are provided, each offset by 120° from one another, as this ensures that the forces are introduced exactly in a centric direction.

According to a preferred embodiment, it is provided that the supports form a collecting space for the released insert. The supports begin with their free end

u - 223 17 February 1997

on the edge of the joint socket and together form a collecting space or cage into which the detached joint insert can fall, so that this joint insert can be fixed in its position even after it has been detached from the instrument and can be removed from this position in a controlled manner by the surgeon.

It is advantageous if the supports have free ends that can be inserted into receiving openings on the edge of the joint socket. For example, the supports can be pointed at the free end and these tips can then be inserted into corresponding recesses on the edge of the joint socket, so that a defined positioning of the surgical instrument relative to the joint socket is guaranteed.

According to a preferred embodiment, it is provided that the supports have sections running perpendicular to the plane formed by the edge of the joint socket and then sections directed towards the central axis of the joint socket. In this way, the supports form the described collecting space for the joint insert and also allow the surgeon an unobstructed view of the joint socket.

It is advantageous if the supports are connected to a central shaft, which carries the striking surface at the end facing away from the supports. The shaft is preferably surrounded by a gripping surface.

According to a preferred embodiment, it is provided that the instrument has a suction holder for the joint insert that can be moved towards the joint socket

u - 223 17 February 1997

This suction mount is sucked onto the joint surface of the joint insert and enables the joint insert, which has been loosened by impacts, to be subsequently removed from the joint socket. It is advantageous if the suction mount can be moved towards the joint socket against the action of a spring. As soon as the joint insert is loosened from the joint socket, such a suction mount can lift the joint insert out of the joint socket under the action of the spring.

The suction mount can, for example, carry a suction cup.

It is also possible for the suction holder to be associated with a device for generating a negative pressure, for example a pump, with which the suction holder is sucked onto the joint surface of the joint insert.

It is advantageous if the suction holder has a handle for moving it. The surgeon can use this handle to bring the suction holder into the engaged position on the joint insert. As soon as the joint insert is released, the surgeon can see that the joint insert has been released from the joint socket by the movement of this handle, which the suction holder performs under the influence of the spring action.

A particularly favourable arrangement is achieved when the suction holder is arranged in the central shaft of the instrument.

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According to a preferred embodiment, it can be provided that the striking surface is designed as a connecting part for a mechanically operated striking tool. This can be, for example, a pneumatically or electrically operated striking tool that is connected to the instrument at the striking surface in such a way that blows generated by the striking tool are transmitted to the instrument. In this sense, the term "striking surface" is to be understood in such a comprehensive way that it refers, on the one hand, to a surface on which a hammer or a similar instrument strikes, but, on the other hand, also to a part of the instrument that absorbs blows generated by a striking tool and transmits them to the instrument.

The following description of preferred embodiments of the invention serves to explain in more detail in conjunction with the drawing. They show:

Figure 1: a side view of a surgical instrument after being placed on the edge of a joint socket;

Figure 2: a top view of the acetabulum of Figure 1 with the surgical instrument attached;

Figure 3: a longitudinal sectional view of a modified instrument for releasing a joint insert with a suction holder for the joint insert before applying the suction holder to the joint insert;

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Figure 4: a view similar to Figure 3 with suction mount attached to the joint insert and

Figure 5: a view similar to Figure 4 after releasing the joint insert from the joint socket.

Figure 1 shows a metal joint socket 1 into which a ceramic joint insert 2 is inserted. The joint insert 2 is held in the joint socket 1 by a clamping cone connection.

At the open end, the joint socket 1 ends in an edge 3 surrounding the joint insert 2, in which circular recesses 4 are arranged offset by 60° in the circumferential direction.

To release the joint insert 2 from the joint socket, a surgical instrument 5 is used which comprises a central shaft 6 with a handle 7 arranged thereon. At its free end, three supports 9 are held on a thickening 8 of the shaft 7, which initially has sections 10 running diagonally outwards from the axis of the shaft 6 and then sections 11 running parallel to the shaft 6. At the free end 12, the supports 9 taper to a point. The three supports 9 are offset by 120° in the circumferential direction and are dimensioned such that the pointed free ends 12 can be inserted into three of the six recesses 4 in the edge 3 of the joint socket 1. In this position, which is shown in Figure 1, the shaft 6 is aligned with the central axis of the joint socket 1.

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In this position, the rear end of the handle 7, designed as a striking surface 13, can be struck with a suitable tool 14, for example with a hammer, so that these blows are transmitted via the instrument 5 to the joint socket 1. These impacts loosen the joint insert 2 from the joint socket 1, i.e. the clamping connection between these two parts is released.

The supports 9 form a collecting space 15 above the interior of the joint socket 1, in which the released joint insert 2 is held captive, so that the surgeon can remove this joint insert 2 in a controlled manner by removing the instrument 5 from the joint socket 1.

The instrument partially shown in Figures 3 to 5 is essentially the same as the instrument in Figures 1 and 2, and therefore identical parts have the same reference numerals

In addition to the features shown in Figures 1 and 2, a piston 16 is mounted in the shaft 6 of this instrument 5 so that it can be moved longitudinally, which can be pushed into the shaft 6 by means of a helical spring 17 surrounding the piston 16 and can be pulled out of it against the action of this spring. The insertion depth of the piston 16 is limited by a step 18 which strikes the underside of the shaft 6.

The piston 16 projects into the collecting chamber 15 formed by the supports 9 and carries at its free

u - 223 17 February 1997

end of a suction cup 19 which extends into the interior of the joint insert 2.

A handle 20 protrudes from the side of the piston 16 and is guided between two adjacent supports 9, so that by pressing on this handle 20 the piston 16 can be displaced against the action of the coil spring 17 in the direction of the arrow in Figure 4. During this displacement the suction cup 19 rests against the joint surface 21 of the joint insert 2 and sucks itself onto it, so that the piston 16 remains in the extended position and is held in this position against the action of the coil spring 17 (Figure 4).

As soon as the joint insert 2 is released from the joint socket 1 by the blows on the instrument 5 in the manner described, the coil spring 17 can push the piston 16 back into the shaft 6, whereby the joint insert 2 held by the suction cup 19 is lifted out of the joint socket 1 (Figure 5). The surgeon recognizes that the joint insert 2 has been released from the joint socket 1 by a movement of the handle 20 and can, after this release of the connection, remove the instrument 5 with the joint insert 2 held by the suction cup 19 from the joint socket 1.

Claims (1)

AESCULAP AG I I . * ' * A »53 V7g*u· u - 223 *17 February 1997 — 9 - PROTECTION CLAIMS 1. Surgical instrument for releasing the clamped fit of a joint insert in a joint socket, characterized by at least two supports (9) that can be placed on the edge (3) of the joint socket (1), which are connected to a striking surface (13) arranged centrally to the joint socket (1) and pointing away from the open side of the joint socket (1). 2. Instrument according to claim 1, characterized in that three supports (9) are provided, each offset by 120° from one another. 3. Instrument according to claim 1 or 2, characterized in that the supports (9) form a collecting space (15) for the released joint insert (2). 4. Instrument according to one of the preceding claims, characterized in that the supports (9) have free ends (11) which can be inserted into receiving openings (4) on the edge (3) of the joint socket (1). AESCULAP AG · ·· ,· ·,&·$£ u - 223 ** " 17 February 1997 - 10 - Instrument according to one of the preceding claims, characterized in that the supports (9) have sections (11) running perpendicular to the plane formed by the edge (3) of the joint socket (1) and adjoining them sections (10) directed towards the central axis of the joint socket (1). 6. Instrument according to one of the preceding claims, characterized in that the supports (9) are connected to a central shaft (6) which carries the beating surface (13) at its end facing away from the supports (9). 7. Instrument according to claim 6, characterized in that the shaft (6) is surrounded by a gripping surface (7). 8. Instrument according to one of the preceding claims, characterized in that it comprises a suction holder (19) for the joint insert (2) that can be moved in the direction of the joint socket (1). 9. Instrument according to claim 8, characterized in that the suction holder (19) can be displaced against the action of a spring (17) in the direction of the joint socket (1). AESCULAP AG : :. S * ! A ·53 *77%**u\ u - 223 """17 February 1997 - 11 - 10. Instrument according to one of claims 8 or 9, characterized in that the suction holder carries a suction cup (19). 11. Instrument according to one of the preceding claims, characterized in that the suction holder is associated with a device for generating a negative pressure. 12. Instrument according to one of the preceding claims, characterized in that the suction holder (19) has a handle (20) for displacement. 13. Instrument according to one of the preceding claims, characterized in that the suction holder is arranged in a central shaft (6) of the instrument (5). 14. Instrument according to one of the preceding claims, characterized in that the striking surface is designed as a connecting part for a mechanically operated striking tool.