DE9318815U1 - Surgical tubular shaft instrument - Google Patents

Description

HOEGER,

PATENT ATTORNEYS UHLANDSTRASSE 14 c · D 7000 STUTTGART 1

A 51 590 u AESCULAP AG

u - 219 Am Aesculap-Platz

3- December 1993 78532 Tuttlingen

SURGICAL TUBULAR SHAFT INSTRUMENT

The invention relates to a surgical tubular shaft instrument with a tube, at the end of which a holder for a tool is detachably held, and with an actuating element arranged in the tube and longitudinally movable therein for moving the tool.

Surgical tubular shaft instruments of this type are used for a wide variety of purposes for cutting, holding, coagulating, etc. Normally, a separate instrument is required for each purpose, but it is also known to arrange the tools detachably on the instrument tube. For this purpose, for example, the tool holders can be designed to be screwed into the tube, with the actuating element being separated at the end of the tube (company brochure of Marlow Surgical Technologies Inc. "Nu-Tip").

Such a connection of the tool holder to the pipe is relatively complicated, in particular it is necessary to exert relatively large forces on the tool and pipe when screwing in and out, and

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The thread requires a certain wall thickness of the tube, which can be a hindrance to the ever-increasing miniaturization of instruments.

It is the object of the invention to design a tubular shaft instrument of the generic type in such a way that the tool can be detachably connected to the tube in a particularly simple manner.

This object is achieved according to the invention in a tubular shaft instrument of the type described at the outset in that the holder carries an extension that can be inserted into the tube and that the tube has radially displaceable parts at its end surrounding the extension, which, in the inserted state, secure the extension against axial displacement in the tube by form or force locking, but in the radially extended state end the engagement and enable the extension to be pulled axially out of the tube.

The pipe is therefore designed to be radially movable in the engagement area of the extension, so that this radial movement alone enables the extension to be released, while in the inserted state a permanent connection can be established by engaging projections and recesses or by force-locking.

A particularly advantageous design is one in which the pipe has tongues bent inwards at its end, separated from one another by longitudinal slots in the pipe casing, which, when pushed in, engage with their inwardly bent ends in recesses on the circumference of the extension. With this solution, it is sufficient to bend the pipe at its

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to divide the extension into tongues at one end by means of longitudinal slots and to bend these inwards at their free end in order to achieve a connection option in this way. When the extension is inserted, the tongues are elastically bent outwards and then lock with their inwardly bent end into the recesses of the extension, so that axial displacement is prevented.

It is advantageous if the recesses are formed by a circumferential ring groove in the extension.

It is also particularly advantageous if the extension is circular-cylindrical in shape, with its outer casing lying flat against the inside of the pipe and having the circumferential ring groove at a distance from its free end. This results in perfect support of the bracket inside the pipe, and by having the circular-cylindrical outer casing of the extension rest against the inside of the pipe over a certain length range, perfect guidance of the extension in the pipe and distribution of the forces to be absorbed over a larger length range are achieved.

In the preferred embodiment, the ring groove can be sawtooth-shaped in cross-section, with the steep flank facing away from the free end of the extension. When the extension is inserted, the inwardly bent free ends of the elastic tongues of the tube slide into the ring groove and abut against the steep flank, thereby limiting the insertion depth. When the extension is pulled out, the inwardly bent

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Ends of the tongues rest on the flat flank and thus enable the extension to be easily pulled out of the pipe.

It can also be provided that the extension has a diverging sliding surface at its free end that merges into the circular-cylindrical area. This makes it easier to insert the extension into the pipe and the resulting elastic bending of the tongue-shaped pipe areas.

To fix the extension in the pipe, an outer pipe is mounted on the pipe so that it can be moved longitudinally. When pushed into the pipe over the engagement area of the extension, this fixes the pipe and extension in a positive or non-positive connection. When pushed away from this area, it enables the pipe to be pushed out radially. This also makes it possible to achieve perfect axial fixation with a relatively material-saving and therefore weak pipe design, since the radial forces for maintaining the positive or non-positive connection are absorbed by the outer pipe, which can be moved longitudinally on the pipe and surrounds it.

It is advantageous if the outer tube can be pushed over a cylindrical area of the extension, which is connected to the engagement area of the extension that is immersed in the tube and which rests against the inner wall of the outer tube. This creates a force-fit connection between the extension and the outer tube, which contributes to the stabilization of the entire instrument, since the outer tube also rests flat against the area on which the extension rests.

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The outer tube thus takes on an additional stiffening function between the extension on the one hand and the tube on the other.

In a particularly preferred embodiment, the outer tube is made of an electrically insulating material. This makes it possible to use the parts arranged inside the outer tube as electrical conductors, for example in instruments used for electrocoagulation. Nevertheless, the surrounding body tissue is reliably protected from the live internal parts of the instrument. The outer tube thus takes on a further function, namely that of electrically insulating the tube and the parts inside it from the environment.

It is advantageous if a reinforcing sleeve is inserted into the end section of the outer tube, which is made of plastic material, for example, and covers the extension. In this area subject to particularly high mechanical stress, the necessary mechanical strength can thus be achieved by this reinforcing sleeve, although the plastic material still retains its electrical insulation properties.

Preferably, the reinforcement sleeve is made of metal.

In particular, it can be arranged on the inside of the outer tube and can seamlessly transition into the adjacent section of the outer tube. This means that there are no difficulties whatsoever when pushing the outer tube onto the tube and extending it.

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It is also advantageous if the holder is coated on the outside with an electrically insulating material that extends to the area covered by the outer tube. This also results in electrical insulation from the environment in the area of the tool itself, which extends over the entire length of the instrument.

In a preferred embodiment, the pipe and the extension are secured against rotation around the pipe's longitudinal axis by positive engagement of projections and recesses relative to one another. In particular, it can be provided that the extension has at least one radially protruding projection which engages in longitudinal slots in the pipe that are open towards the end of the pipe.

This makes it possible to design the connection between the tool holder on the one hand and the pipe on the other in such a way that only the axial fixing needs to be taken into account, not the rotation fixing. This is done by the special anti-rotation device. This simplifies the design of the connection between the tool holder on the one hand and the pipe on the other. In addition, this solution provides protection against any rotation compared to a connection using a screw-in thread. When using screw-in threads, it cannot be ruled out that the screw connection could be accidentally loosened during operation due to high torques. This risk is eliminated with the new design described.

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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 schematic side view of a tubular shaft instrument;

Figure 2: a partially broken side view of the front part of the preferred embodiment of a tubular shaft instrument with the tool fixed to the tube;

Figure 3: a view similar to Figure 2 with the tool removed from the pipe and

Figure 4: an enlarged view of the front part of another preferred embodiment of a tubular shaft instrument with electrical insulation (without tools).

The surgical tubular shaft instrument is described below using the example of an instrument that can be operated with two handle branches that can be pivoted against each other. However, it is understood that any type of instrument in which an actuating element is slidably mounted in a tube, which actuates a tool at the end of the tube. The actuating element can also be driven in a way other than by handle branches that can be pivoted against each other, in which case

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for example by direct displacement of the actuating element or by special motor drive means.

The tubular shaft instrument described in the drawing comprises two handle branches 1, 2 which are pivotably mounted relative to one another and each have a finger opening 3 or 4, respectively, which are pivotally connected to one another at a bearing point 5.

One of the handle branches 1 carries an elongated tube 6, at the free end of which a tool 7 is held, which can be designed, for example, as pliers or scissors.

Inside the tube 6 there is an actuating element in the form of a push and pull rod 8, which is connected via joints on the one hand to the tool 7 and on the other hand to the other handle branch 2. By opening and closing the handle branches 1 and 2, the push and pull rod 8 is displaced lengthwise in the tube 6 and thereby actuates the tool 7.

The structure of the tubular shaft instrument in the area of the transition point between the tube 6 on the one hand and the tool 7 on the other hand is explained in more detail using Figures 2 to 4.

The tool 7 comprises a holder 9 on which movable parts 10, 11 of the tool are rotatably mounted. In addition, the holder 9 accommodates gear means 12 which are rotatably connected to the push and pull rod 8 and which translate a movement of the push and pull rod into a rotary movement of the parts 10 and 11.

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The holder 9 merges into a stepped, circular-cylindrical extension 13 on its side facing the pipe 6, which has a section 14 with a smaller outer diameter adjacent to the end of the extension 13 and an adjoining section 15 with a larger outer diameter. In the transition area between the two sections 14 and 15, there is a circumferential groove 16 in the extension 13, which is formed by a conical profile of the lateral surface of the section 14. This gives the circumferential groove 16 a sawtooth cross-section with a steep flank 17 formed by the step between the sections 14 and 15 and with a flat flank 18 merging into the cylindrical surface of the section 14.

At the free end of the extension 13, a conical sliding surface 19 is formed, which also merges into the cylindrical surface of the section 14. The extension 13 accommodates a central bore 20 in which the push and pull rod 8 is arranged to run up to the gear parts 12. This push and pull rod 8 can be a continuous rod; in the embodiment shown, it is formed in two parts and widens inside the tube 6; this is not absolutely necessary.

The tube 6 is divided at its free end by several longitudinal slots 21 into tongue-shaped wall areas 22, which are slightly bent radially inwards at the free end of the tube 6. The angle of these tongue-shaped wall areas 22 essentially corresponds to the angle of the flat flank 18 of the circumferential groove 16, and the length of the angled area is also selected so that the bent part of the tongue-shaped wall area 22

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is approximately the same length as the flat flank 18 of the circumferential groove 16. The outer diameter of the section 14 corresponds to the inner diameter of the pipe 6. A screw 23 is screwed into the section 14 in the radial direction, which slightly protrudes beyond the outer diameter of the section 14 and whose diameter corresponds to the width of the longitudinal slots 21 in the pipe 6.

An outer tube 24 is arranged on the tube 6 so as to be longitudinally displaceable, the inner diameter of which corresponds to the outer diameter of the tube. This inner diameter also corresponds to the outer diameter of the section 15 of the extension.

This outer tube can be made of metal as shown in Figures 2 and 3, but it is advantageous if this outer tube 24 is made of an electrically insulating material, for example plastic, as shown in the embodiment in Figure 4. In this case, a reinforcing sleeve 25 is inserted into the area near the end of the outer tube 24 (Figure 4), which can be made of metal, for example. The reinforcing sleeve 25 is preferably arranged on the inside of the outer tube 24 and fitted in such a way that the inner wall of the outer tube 24 is stepless. In an embodiment with an outer tube made of electrically insulating material, it is also advantageous if the holder 9 is coated on the outside with an electrically insulating material 26, for example also with plastic. This preferably extends into the section 15 of the extension 13, so that the electrically insulating outer tube 24 can connect directly to this electrically insulating material 26, sometimes even overlapping it.

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When connecting a tool 7 to a pipe 6, the outer pipe 24, which is slidably mounted on the pipe 6, is first pushed back relative to the pipe 6 to such an extent that the tongue-shaped wall areas 22 of the pipe 6 are released and can therefore be elastically bent outwards. In the manner shown in Figure 3, a tool 7 is brought up to the pipe 6 in such a way that the sliding surface 19 of the extension 13 rests on the free ends of the tongue-shaped wall areas 22 and thereby elastically displaces them radially outwards. As the section 14 is pushed further into the pipe 6, the tongue-shaped wall areas 22 slide along its outer surface until the bent parts of the tongue-shaped wall areas 22 reach the circumferential groove 16. The displacement movement is limited by the tongue-shaped wall areas 22 resting on the steep flank 17. When this position is reached, the tongue-shaped wall areas 22 lie flat with their cylindrical part against the cylindrical surface of the section 14, while the bent parts of the tongue-shaped wall areas 22 engage in the circumferential groove 16, preferably with flat contact with the flat flank 18, as shown in Figure 2. The extension is secured against rotation relative to the pipe 6 by the engagement of the screw 23 in one of the longitudinal slots 21. To permanently fix this connection, the outer pipe 24 is then pushed over the pipe 6 so far that the tongue-shaped wall areas 22 are fixed in the radial direction, i.e. can no longer move radially outwards. The outer pipe 24 is pushed completely over the section 15 of the extension 13, so that this stiffens the connection area. Bracket 9 and

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Pipe 6 is thus fixed in an axial direction and the coaxial interlocking of pipe 6, outer pipe 24 and extension 13 also results in a rigid connection between bracket 9 and pipe 6.

This connection can be released again in the simplest way if the outer tube 24 is pulled back and the tongue-shaped wall areas 22 are released again. It is then possible to pull the tool 7 out of the tube 6, whereby the push and pull rod 8 is pulled out with it.

In the embodiment of Figure 4, in the assembled state with the outer tube 24 pushed forward, a complete electrically insulating sheathing of the entire shaft part of the instrument is obtained, so that this instrument can be used for electrical processing operations.

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Claims (1)

A 51 590 u AESCULAP AG u - 219 Am Aesculap-Platz 3 December 1993 78532 Tuttlingen PROTECTION CLAIMS 1. Surgical tubular shaft instrument with a tube, at the end of which a holder for a tool is detachably held, and with an actuating element arranged in the tube and movable longitudinally therein for moving the tool, characterized, that the holder (9) carries an extension (13) that can be inserted into the tube (6) and that the tube (6) has radially displaceable parts (22) at its end surrounding the extension (13), which in the inserted state secure the extension (13) against axial displacement in the tube (6) by means of a positive or non-positive connection, but in the radially extended state end the engagement and enable the extension (13) to be pulled axially out of the tube (6). 2. Instrument according to claim 1, characterized in that the tube (6) has tongues (22) bent inwards at its end, separated from one another by longitudinal slots (21) in the tube casing, which, when pushed in, engage with their inwardly bent end in recesses (16) on the circumference of the extension (13). AESCULAP AG ^: ..··..* * .5. .ll. * I'·**··' ^A 51590 u 3 December 1993 "* * u-219 - 14 - 3. Instrument according to claim 2, characterized in that the recesses (16) are formed by a circumferential annular groove in the extension (13). 4. Instrument according to claims 2 and 3, characterized in that the extension (13) is circular-cylindrical in shape, with its outer casing rests flatly on the inside of the tube (6) and has the circumferential ring groove at a distance from its free end. 5. Instrument according to claim 4, characterized in that the circumferential ring groove is sawtooth-shaped in cross section, with the steep flank (17) facing away from the free end of the extension (13). 6. Instrument according to claim 4 or 5, characterized in that the extension (13) has at its free end a diverging sliding surface (19) merging into the circular-cylindrical region (14). Instrument according to one of the preceding claims, characterized in that an outer tube (24) is mounted on the tube (6) so as to be longitudinally displaceable, which, when pushed into the tube (6) over the engagement area of the extension (13), fixes the tube (6) and the extension (13) in a positive or non-positive fit, but when pushed away from this area, enables the tube (6) to be pushed out radially. AESCULAP AG ·..··..' .:..:.. ..·*··" A 51590 u 3 December 1993 * u-219 - 15 - 8. Instrument according to claim 7, characterized in that the outer tube (24) can be pushed over a cylindrical region (15) of the extension (13) which adjoins the engagement region (14) of the extension (13) which penetrates into the tube (6) and which rests against the inner wall of the outer tube (24). 9. Instrument according to claim 7 or 8, characterized in that the outer tube (24) consists of an electrically insulating material. 10. Instrument according to claim 9, characterized in that a reinforcing sleeve (25) is inserted into the outer tube (24) in its end section covering the extension (13). 11. Instrument according to claim 10, characterized in that the reinforcing sleeve (25) consists of metal. 12. Instrument according to claim 10 or 11, characterized in that the reinforcing sleeve (25) is arranged on the inside of the outer tube (24) and merges seamlessly into the adjoining section of the outer tube (24). AESCULAP AG &idgr;&idgr;&idgr;_##&idgr; .:..:,. ..·'..* ^&Agr; 51590 u 3 December 1993 u-219 - 16 - 13. Instrument according to one of claims 9 to 13, characterized in that the holder (9) is coated on the outside with an electrically insulating material (26) which extends into the area covered by the outer tube (24). 14. Instrument according to one of the preceding claims, characterized in that the tube (6) and extension (13) are secured against rotation about the longitudinal axis of the tube by positive engagement of projections and recesses (23, 21) relative to one another. 15. Instrument according to claim 14, characterized in that the extension (13) carries at least one radially projecting projection (23) which engages in longitudinal slots (21) in the tube (6) which are open towards the end of the tube (6).