DE20311293U1 - Surgical instrument with tubular shaft, contains flexible transmission comprising sections connected by ball joints - Google Patents

Abstract

The flexible transmission (5) inside the shaft (2) comprises a number of sections (9) which are arranged one after the other and are in contact with the inside of the shaft. A ball joint-type connection is provided in between adjoining transmission sections.

Description

SURGICALTUBESHAFTINSTRUMENT

The invention relates to a surgical tubular shaft instrument with a tubular flexible shaft and with a longitudinally displaceable and bendable force transmission element accommodated therein.

Such an instrument is described, for example, in DE 195 20 717 C2.

In this known design, a push and pull rod guided inside the shaft is reduced in diameter in some areas so that bending is possible in this area, while in other areas where the diameter is not reduced, the push and pull rod rests on the inside of the shaft and is thus protected against buckling. However, with this design, the transmission of very high compressive forces is not possible if the support points with large diameters are far apart from each other, and if they are very close together, flexibility is limited.

It is the object of the invention to design a shaft instrument of this type in such a way that the transmission of high compressive forces is possible with high flexibility.

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This object is achieved according to the invention in a surgical tubular shaft instrument of the type described at the outset in that the force transmission element consists of a number of individual sections which are arranged one behind the other on the inner wall of the shaft and have a ball-joint-like connection in the contact area of two individual sections. This larger number of individual sections therefore makes it possible to pivot the force transmission element in any direction at the ball-joint-shaped connection points, so that the force transmission element has a high degree of flexibility overall, but at the same time the entire cross-section of the shaft is used to be able to transmit compressive forces in this area. Lateral buckling of the individual sections is not possible, and the compressive forces can be reliably transmitted to the adjacent individual section via the ball joint.

For example, in a preferred embodiment, an individual section can have a spherical bearing cup in the contact area with the adjacent individual section and the adjacent individual section then has a spherically protruding bearing surface that dips into the bearing cup. The bearing cup can be closed and the spherically protruding bearing surface can also be closed, so that the entire bearing surface is available for force transmission.

The edge of the bearing cup can surround the adjacent individual section with an elastic locking or snap-in connection, so that the two adjacent individual sections can be plugged together in the axial direction in this way, thus obtaining a longer force transmission element made up of individual sections, all of which are held together by the locking connection.

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and can be pivoted against each other, whereby the pivoting capability naturally does not require too great an angle change for each individual ball joint in order to nevertheless ensure sufficient flexibility for the entire power transmission element.

In another embodiment, the bearing cup is formed by an annular bearing surface with a circular contour on the inner surface of the individual section in the form of a piece of pipe. The spherical bearing surface of the adjacent individual section thus dips into the interior of the first individual section and is guided in this annular bearing surface with a circular contour; the pressure forces can also be transmitted in this area.

It is possible for the individual section in the area of the ring-shaped bearing surface to be divided by incisions into tabs lying next to one another in the circumferential direction, which can preferably be bent elastically outwards. This also makes it possible to create an elastic snap-in or latching connection.

The force transmission element described is particularly suitable for transmitting compressive forces. However, it can be provided that a flexible tension element is passed through the individual sections, which is used, for example, in the form of a thin, flexible rod or a rope, in which case the force transmission element is also ideally suited for transmitting tensile forces.

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The tension element can be passed through a central opening in each individual section.

In a preferred embodiment, the individual sections are concavely curved in the longitudinal direction between their ends. The curvature is preferably selected so that it corresponds to the curvature of the inside side of the shaft when the shaft is bent to the maximum. In this case, the shaft can rest against the outer contour of the individual sections so that the individual sections are given additional guidance, and a maximally bent configuration is also defined.

In a preferred embodiment, the individual sections can be surrounded by a common flexible hose or a plastic sheath that is pulled over the individual sections or molded around them.

The shaft instrument described can in particular be constructed in such a way that the shaft is inserted into a handle and is secured in the inserted position by a detachable fixing device in the handle. This allows the shaft to be removed from the handle and thus improves cleaning options; moreover, different shafts can be used with the same handle.

In a preferred embodiment, the fixing device can have a spring-loaded pivot lever which, in a locking position, secures the shaft against axial displacement by engaging a projection in a recess. This provides a very simple

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A locking device that allows the shaft to be released simply by operating the spring-loaded pivot lever.

It is advantageous if the shaft is secured against rotation about its longitudinal axis when inserted into the handle.

Furthermore, it can be provided that the force transmission element is detachably connected to an actuating device at its end on the handle part side. This also enables separation in the handle part area; if necessary, the shaft and force transmission element can be separated together from the handle part and the actuating device arranged there.

It is particularly advantageous if the detachable connection is formed by a slide-in coupling which initially has no connection to the actuating device when the power transmission element is pushed into the slide-in coupling and which only creates a connection when the power transmission element is pushed in further. The connection is thus created by the pushing-in movement itself; no additional coupling processes are necessary. Conversely, this connection can be released simply by pulling the power transmission element out of the slide-in coupling.

For example, the insert coupling can comprise a driver with a slot that is open on one side and into which a projection of the force transmission element can be inserted.

The design is particularly advantageous if the driver with the slot is pivotably mounted on the handle part between an insertion position in which the

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The projection of the force transmission element can enter the open end of the slot when inserted into the handle part, and a coupling position in which the slot runs essentially transversely to the direction of displacement of the force transmission element. In this design, the projection can therefore easily enter the slot in the inserted position, but not in the coupling direction, which runs essentially transversely thereto.

It is possible for the driver to be pivotable by the actuating device and, in its coupling position, to axially displace the force transmission element via the projection engaging in the slot. The driver thus serves not only to couple the force transmission element to the actuating device, but also to transmit movement from the actuating device to the force transmission element. For example, the driver itself can be part of a pivotable handle branch of the handle part.

It is particularly advantageous if the driver is positioned at an angle to the direction of displacement of the power transmission element when the power transmission element is inserted, such that the latter pivots the driver into the coupling position when it is inserted further.

It is also advantageous if the driver is pivoted into the inserted position by a spring; in particular, this spring can be a bending spring which is held on the pivot lever which secures the shaft against axial displacement.

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According to a preferred embodiment, the force transmission element can be connected to a tool at its tool-side end via a detachable bayonet coupling, whereby the term "tool" can also be understood to mean a transmission member which connects the force transmission element to an actual tool.

It is advantageous if the tool has a receiving recess for the end of the force transmission element; in particular, the end of the force transmission element and the receiving recess can be conical.

In a preferred embodiment, the bayonet locking can be achieved by axially bringing together the force transmission element and the tool and by subsequently rotating the two parts against each other about the longitudinal axis of the force transmission element.

It is advantageous if the tool has a locking projection which projects in the direction of the force transmission element and is guided in an L-shaped path of the force transmission element.

The ability to detach the shaft and/or the force transmission element from the handle part and the ability to connect the force transmission element to the handle part and the ability to connect the force transmission element to the tool can be used advantageously in a surgical tubular shaft instrument with a flexible shaft and a flexible force transmission element, but in principle it can also be used in other types of tubular shaft instruments. The protection therefore also applies to tubular shaft instruments with such designs that do not have a flexible

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shaft and no flexible force transmission element, but are designed in a different way.

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 forceps- or scissors-shaped tubular shaft instrument with a flexible shaft;

Figure 2: a longitudinal sectional view through the flexible region of the shaft;

Figure 3: a schematic representation of two elastically connected individual sections of the force transmission element with a tension element passing through them;

Figure 4: a side view of another preferred embodiment of a tubular shaft instrument with a possibility of detaching the shaft and the force transmission element from the handle part and a detachable connection between the force transmission element and the tool;

Figure 5: an enlarged detailed view of the bearing area of the shaft in the handle part of the instrument of Figure 4 with the shaft locked and the force transmission element coupled;

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Figure 6: a view similar to Figure 5 with the shaft and force transmission element uncoupled;

Figure 7: an enlarged detailed view of the connection area between the force transmission element and the tool and

Figure 8: a plan view of the instrument of Figure 7.

The invention is discussed using a forceps- or scissors-shaped tubular shaft instrument, but it is understood that the invention can be used with all tubular shaft-shaped instruments in which a force transmission element is guided inside a shaft, which transmits a movement from the proximal to the distal end through the shaft.

The tubular shaft instrument 1 shown in the drawing has an elongated, tubular shaft 2 which is flexible at least in its distal region 3. In a manner known per se, this can be a shaft made of a plastic material or a thin-walled metal tube which is flexible within certain limits.

At the distal end of the shaft 2, working elements 4 are mounted which can be moved relative to one another. For example, the working elements 4 can be two clamping jaws which can be pivoted relative to one another or two blades of a pair of scissors which can be pivoted relative to one another. In order to move these working elements, a flexible force transmission element 5 which completely penetrates the shaft 2 is arranged inside the shaft 2 and which protrudes from the shaft 2 at the proximal end. In this area, the

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Shaft 2 is rigidly connected to a handle branch 6, on which a second handle branch 7 is pivotably mounted. The force transmission element 5 is hinged to this second handle branch 7, so that when the handle branch 7 pivots relative to the handle branch 6, the force transmission element 5 is displaced longitudinally relative to the shaft 2. This displacement of the force transmission element 5 is translated in the distal area by suitable gear elements into a pivoting movement of the working elements 4; in the embodiment shown, toggle lever connections 8 are provided, by means of which the longitudinal movement is converted into a pivoting movement.

The force transmission element 5 is constructed, at least in its flexible part, from individual sections 9 which are in frictional contact with one another in the longitudinal direction of the force transmission element 5. In the embodiment shown, each individual section 9 is designed as a piece of pipe which is closed at its distal end by a spherical end face 10 which extends over a circumferential angle of slightly more than 180°. On the opposite side, each individual section 9 is divided into several tabs 12 by axially parallel incisions 11; these tabs 12 are provided on their inside with an annular bearing surface 13 which runs around the circumference and has a circular arc-shaped contour. The tabs 12 are slightly elastically deformable outwards, so that two adjacent individual sections 9 can be connected to one another by inserting one individual section 9 with the spherical end face 10 into the open end of the other individual section 9, the tabs 12 are elastically bent open and the spherical end face 10 snaps elastically into the annular bearing surface 13. In this way, a ball-joint-shaped connection is obtained.

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connection of adjacent individual sections 9, by which a certain pivotability of adjacent individual sections 9 in all directions is ensured, but at the same time also a force transmission in the axial direction, since the tabs 12 are prevented from radial outward movement after the force transmission element has been inserted into the shaft 2.

In addition, it could be provided that the individual sections 9 are designed as a spherical pan on their side opposite the spherical front surface, which extends over the entire cross section, in this case the annular bearing surface 13 would be continued in a bearing pan covering the entire cross section.

A flexible tension member 14 is passed through central openings in the spherical front surface 10, which can be designed, for example, as a thin flexible rod or as a cable, so that compressive forces can be optimally transmitted by the force transmission member 5 through the contact of the spherical bearing surfaces with one another, while tensile forces are optimally transmitted by the tension member 14.

Each individual section 9 is slightly concavely constricted in the longitudinal direction between its ends, the contour of this constriction is essentially circular in shape and its curvature corresponds to the smallest curvature that occurs on the inside of the shaft 2 when it is completely curved. In this case, the shaft 2 can rest against the outside of the individual sections, which leads to optimal mutual support when transmitting pressure forces and also limits the flexibility of the entire shaft arrangement.

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The entire arrangement is very easy to assemble and can also be easily dismantled for cleaning purposes. All that is required is to remove the force transmission element 5 from the shaft, then the individual sections 9 can be easily pulled apart and then put back together. On the inside of the shaft 2, however, the individual sections, which are spherically connected to one another, cannot come loose because the tabs 12 cannot move radially outwards.

The shaft 2, the force transmission element 5 and the handle part comprising the handle branches 6, 7 can be detachably connected to one another, and it is also possible for the force transmission element 5 to be detachably connected to one of the tools 4. Possible types of connection are described below for a further embodiment of a tubular shaft instrument, as shown in Figures 4 to 8. The possibility of connecting the shaft and/or the force transmission element to the handle part and the force transmission element to the tool is not limited to the design of a tubular shaft instrument, as described with reference to Figures 1 to 3, but this design can also be used for tubular shaft instruments in which the shaft and force transmission element are designed differently, for example rigidly.

Corresponding parts bear the same reference numerals as in the embodiment of Figures 1 to 3.

As in the embodiment of Figures 1 to 3, two handle branches 6, 7 are provided in the embodiment of Figures 4 to 8, whereby

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a handle branch 6 can be rigidly connected to the shaft 2, although in this case the connection is detachable. For this purpose, the handle branch 6 has an insertion opening 21 for the shaft 2 at its front end 20, and a pin 22 fixed to the handle branch 6 projects radially slightly into this insertion opening 21 on the underside of the insertion opening 21. This pin 22 dips into a longitudinal groove 23 of the shaft 2 when the latter is inserted into the insertion opening 21, so that a rotation lock is formed, and the pin 22 at the end of the longitudinal groove 23 also limits the insertion depth of the shaft 2 into the insertion opening 21.

On its side opposite the longitudinal groove 23, the shaft 2 has a recess 24, which can be formed, for example, by a square opening in the wall of the shaft or by a recess.

This recess 24 is arranged such that when the shaft 2 is fully inserted, a projection 25 of a pawl 26 can engage in this recess 24 and thereby fix the shaft 2 in the axial direction. This pawl 26 is pivotably mounted in a larger recess 27 into which the insertion opening 21 opens; the pivot axis runs parallel to the pivot axis of the two handle branches 6, 7 and is located approximately in the middle of the pawl 26. Therefore, if you press on the rear part of the pawl 26, the projection 25 arranged on the front of the pawl lifts out of the recess 24 of the shaft 2 and releases the shaft 2; conversely, the projection 25 sinks into the recess 24 if you do not press down the pawl 26; in this case the pawl 26 is held in this locking position by a leaf-shaped bending spring 28. The bending spring 28 is inserted into a slot 29 of the pawl 26.

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The end of the shaft 2 facing the pawl 26 is bevelled so that when the shaft 2 is inserted through the insertion opening, the pawl 26 is raised by this bevelled end against the action of the bending spring 28 until the shaft 2 is inserted so deeply into the insertion opening 21 that the projection 25 can enter the recess 24 and thereby establish the axial locking.

A helical spring 31 is inserted into a blind hole 30 of the locking pawl 26; this spring rests on a support surface 22 of the handle branch 6 and thus prevents the locking pawl 26 from being inadvertently pressed in; only after overcoming a certain pressure force can the locking pawl 26 be pivoted in the direction of releasing the shaft 2.

The other handle branch 7 is pivotally mounted on the handle branch 6 in the region of the recess 27 and ends above the pivot axis in a driver 33 in which a slot 34 is arranged which is open towards the free end and slightly widens in width towards the open end.

The driver can be designed as a fork with two wall parts running parallel to each other, each receiving its own slot 34, but it could also be provided that such a wall part is arranged only on one side of the driver 33.

The force transmission element 5 protrudes from the rear of the shaft 2 and carries a coupling piece 35 with laterally protruding driving pins 36, which, when assembled, fit into the slots 34 of the driving pin.

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mers 33 and thereby form a swivel joint, via which the force transmission element 5 in the shaft 2 can be pushed forwards and backwards when the handle branch is swiveled (Figure 5). The driver 33 is swiveled in a coupling area in which the coupling is permanently maintained. The dimensions are selected so that the two handle branches 6 and 7 do not come completely close to each other when the tools are closed, but the closing movement is ended by the tools coming into contact with each other, whereby a distance remains between the handle branches 6 and 7.

If the shaft 2 is pulled forwards out of the handle branch 6 after releasing the pawl 26, this inevitably results in a pivoting of the driver 33 and thus of the handle branch 7, since the force transmission element 5 is also moved forwards with the shaft 2 and in the process pivots the driver 33. The pivoting goes so far that the driving pins 36 can emerge forwards from the slot 34 of the driver 33 (Figure 6), so that both the shaft 2 and the force transmission element 5 can be freely pulled out of the handle branch 6.

The bending spring 28 is supported on the driver 33 in such a way that the driver

33 is pivoted into this front pivot position so that the slot

34 remains in the position it assumed when the power transmission element 5 was pulled out when the shaft 2 and the power transmission element 5 are pulled out. This means that, conversely, when the power transmission element 5 is pushed in again, the driving pins 36 can enter the slot 34 and, when they hit the side wall,

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of the slot 34 and, upon further insertion, move the driver 33 against the curvature of the spiral spring 28 into the coupling position in which pulling out the driver pins 36 in the direction of displacement of the force transmission element 5 is no longer possible.

Overall, this provides a very simple way of connecting both the shaft and the power transmission element to the fixed handle branch 6 and of separating these parts from each other again. When pushed in, the driver pins 36 automatically enter the slot 34 and pivot the driver 33 into the coupling position and thus into the actual working position, at the same time the beveled end of the shaft 2 pivots the pawl 26 into the open position so that the rear end of the shaft 2 can slide past the projection 25 until it enters the recess 24 and thus secures both the shaft 2 and the power transmission element 5 in the axial direction. The shaft 2 can then no longer be moved in the axial direction, the power transmission element 5 only to a limited extent in accordance with the pivoting movement of the driver 33.

To separate, it is sufficient to press the pawl 26, then the shaft 2 and power transmission element 5 can be easily pulled forwards out of the handle branch 6.

To connect the power transmission element 5 to a working element 4, the latter has a slightly conically tapering central receiving opening 37 into which a complementary end 38 of the power transmission element can be inserted. On this end 38 of the power transmission element

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5 has an L-shaped guide track 39 incorporated therein, which initially runs parallel to the axis from the front end and then bends at a right angle, making it L-shaped overall. When the end 38 is pushed into the receiving opening 37, a pin 40, for example a screwed-in grub screw, which projects slightly inwards into the receiving opening 37, enters this guide track 39 and, when pushed in, initially runs in the part of the guide track 39 that is parallel to the axis. When the end of this part of the guide track that is parallel to the axis is reached, the end 38 and the working element 4 are rotated against one another about the longitudinal axis of the force transmission element 5, and this leads to the pin 40 entering the part of the guide track 39 that runs in the circumferential direction. This leads to an axial securing of the end 38 in the receiving opening 37 and thus to a permanent operative connection between the force transmission element 5 on the one hand and the working element 4 on the other. The solution can be implemented in the opposite way.

Claims (28)

1. Surgical tubular shaft instrument with a tubular flexible shaft and with a longitudinally displaceable and bendable force transmission element received therein, characterized in that the force transmission element ( 5 ) consists of a number of individual sections ( 9 ) which are arranged one behind the other adjacent to the inner wall of the shaft ( 2 ) and have a ball-joint-like connection ( 10 , 13 ) in the contact area of two individual sections ( 9 ). 2. Surgical tubular shaft instrument according to claim 1, characterized in that an individual section ( 9 ) has a spherical bearing cup ( 13 ) in the contact area with the adjacent individual section ( 9 ) and the adjacent individual section ( 9 ) has a spherically projecting bearing surface ( 10 ) which dips into the bearing cup ( 13 ). 3. Surgical tubular shaft instrument according to claim 2, characterized in that the edge of the bearing cup ( 13 ) surrounds the adjacent individual section ( 9 ) with an elastic locking or snap-in connection. 4. Surgical tubular shaft instrument according to one of the preceding claims, characterized in that a flexible tension element ( 14 ) is passed through the individual sections ( 9 ). 5. Surgical tubular shaft instrument according to claim 4, characterized in that the tension element ( 14 ) is a thin flexible rod or a rope. 6. Surgical tubular shaft instrument according to claim 4 or 5, characterized in that the pulling element ( 14 ) is guided through a central opening in each individual section ( 9 ). 7. Surgical tubular shaft instrument according to one of the preceding claims, characterized in that the individual sections ( 9 ) are concavely curved in the longitudinal direction between their ends. 8. Surgical tubular shaft instrument according to claim 7, characterized in that the curvature corresponds to the curvature of the inner side of the shaft ( 2 ) at maximum bending of the shaft ( 2 ). 9. Surgical tubular shaft instrument according to one of the preceding claims, characterized in that the individual sections ( 9 ) are surrounded by a common flexible hose or plastic sheath. 10. Surgical tubular shaft instrument according to one of the preceding claims, characterized in that the bearing cup is formed by an annular bearing surface ( 13 ) with a circular arc-shaped contour on the inner jacket of the tubular individual section ( 9 ). 11. Surgical tubular shaft instrument according to claim 10, characterized in that the individual section ( 9 ) is divided in the region of the annular bearing surface ( 13 ) by incisions ( 11 ) into tabs ( 12 ) lying next to one another in the circumferential direction. 12. Surgical tubular shaft instrument according to claim 11, characterized in that the tabs ( 12 ) are elastically bendable outwards. 13. Surgical tubular shaft instrument according to one of the preceding claims, characterized in that the shaft ( 2 ) is inserted into a handle part ( 6 ) and is fixed in the inserted position by a releasable fixing device ( 24 , 25 , 26 ) in the handle part ( 6 ). 14. Surgical tubular shaft instrument according to claim 13, characterized in that the fixing device has a spring-loaded pivot lever ( 26 ) which, in a locking position, secures the shaft ( 2 ) against axial displacement by engagement of a projection ( 25 ) in a recess ( 24 ). 15. Surgical tubular shaft instrument according to claim 13 or 14, characterized in that the shaft ( 2 ) is secured against rotation about its longitudinal axis in its position inserted into the handle part ( 6 ). 16. Surgical tubular shaft instrument according to one of claims 13 to 15, characterized in that the force transmission element ( 5 ) is detachably connected to an actuating device ( 7 , 33 ) at its handle-side end. 17. Surgical tubular shaft instrument according to claim 16, characterized in that the detachable connection is formed by a push-in coupling ( 33 , 34 , 35 , 36 ) which initially has no connection to the actuating device when the force transmission element ( 5 ) is pushed into the push-in coupling and which only establishes a connection when the force transmission element ( 5 ) is pushed in further. 18. Surgical tubular shaft instrument according to claim 17, characterized in that the insertion coupling comprises a driver ( 33 ) with a slot ( 34 ) open on one side, into which a projection ( 36 ) of the force transmission element ( 5 ) can be inserted. 19. Surgical tubular shaft instrument according to claim 18, characterized in that the driver ( 33 ) is pivotably mounted on the handle part ( 6 ) between an insertion position in which the projection ( 36 ) of the force transmission element ( 5 ) can enter the open end of the slot ( 34 ) when inserted into the handle part ( 6 ), and a coupling position in which the slot in ( 34 ) runs essentially transversely to the direction of displacement of the force transmission element ( 5 ). 20. Surgical tubular shaft instrument according to claim 19, characterized in that the driver ( 33 ) can be pivoted by the actuating device ( 7 ) and in its coupling position axially displaces the force transmission element ( 5 ) via the projection ( 36 ) engaging in the slot ( 34 ). 21. Surgical tubular shaft instrument according to one of claims 19 or 20, characterized in that the driver ( 33 ) is positioned obliquely to the direction of displacement of the force transmission element ( 5 ) when the force transmission element ( 5 ) is pushed in, such that the latter pivots the driver ( 33 ) into the coupling position when it is pushed in further. 22. Surgical tubular shaft instrument according to one of claims 19 to 21, characterized in that the driver ( 33 ) is pivoted into the inserted position by a spring ( 28 ). 23. Surgical tubular shaft instrument according to claim 22, characterized in that the spring ( 28 ) is a bending spring which is held on the pivot lever ( 26 ) which secures the shaft ( 2 ) against axial displacement. 24. Surgical tubular shaft instrument according to one of the preceding claims, characterized in that the force transmission element ( 5 ) is connected to a tool ( 4 ) at its tool-side end ( 38 ) via a detachable bayonet coupling ( 39 , 40 ). 25. Surgical tubular shaft instrument according to claim 24, characterized in that the tool has a receiving recess ( 37 ) for the end ( 38 ) of the force transmission element ( 5 ). 26. Surgical tubular shaft instrument according to claim 25, characterized in that the end ( 38 ) of the force transmission element ( 5 ) and the receptacle ( 37 ) are conical. 27. Surgical tubular shaft instrument according to one of claims 24 to 26, characterized in that the bayonet locking is carried out by axially bringing together the force transmission element ( 5 ) and the tool ( 4 ) and by a subsequent rotation of the two parts ( 4 , 5 ) against each other about the longitudinal axis of the force transmission element ( 5 ). 28. Surgical tubular shaft instrument according to claim 27, characterized in that the tool ( 4 ) carries a locking projection ( 40 ) projecting in the direction of the force transmission element ( 5 ) which is guided in an L-shaped track ( 39 ) of the force transmission element ( 5 ).