DE29916804U1 - Reduction tools - Google Patents

Description

A 55 144 u Aesculap AG & Co. KG

u - 223/248 Am Aesculap Platz

22 September 1999 78532 Tuttlingen

Repositioning instruments

The invention relates to a repositioning instrument for fragment fractures of long bones with a shaft-shaped fixation nail having transverse fixation holes that can be inserted into the long bone and with a targeting device that can be connected to the nail via fixation elements.

When treating complex fragment fractures in the area of the head of a long bone, especially the humerus bone, it is common practice to insert a shaft-shaped fixation nail into the long bone, which has transverse holes through which bone screws are passed, with which the bone fragments are attached to the fixation nail.

The necessary holes in the bone fragments are preferably made using a targeting device that is connected to the fixation nail and indicates the direction to the surgeon, which corresponds to the direction of the fixation holes.

However, in the case of head fractures, difficulties arise when the head is to be completely rebuilt from the bone fragments, since without an opening in the

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Head these targeting devices cannot be connected to the fixation nail in known fixation nails, the connection is usually made in the direction of the longitudinal axis of the fixation nail via fixation elements that engage there.

It is the object of the invention to design a repositioning instrumentation in such a way that, even without an opening in the head part to be reconstructed, a targeting device can be fixed to the fixation nail, with which it is possible to insert holes for bone screws into the individual bone fragments that are aligned with the fixation holes in the fixation nail.

This object is achieved in a repositioning instrument of the type described at the outset in that pin-shaped fixing elements can be inserted into several fixation holes over a wide range in a reproducible manner and can be fixed in this position, that the targeting device has several through holes for receiving such fixing elements essentially without play, that the fixation holes and the through holes are arranged in such a way that at a certain position of the targeting device relative to the fixation nail, one fixation hole and one through hole are aligned with each other at the same time, that the fixing elements can be fixed in the through holes in the axial direction in such a way that the targeting device can be fixed in this certain position relative to the fixation nail when the fixing elements are inserted into the fixation holes and fixed in them, and that the pin-shaped

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The fixing elements can be pulled out of the through holes of the target device after this fixation and the fixing in the fixation holes have been released.

Such a design makes it possible to position the targeting device to the side of the long bone using the fixing elements inserted into the fixation holes, with the fixing elements running essentially radially relative to the fixation nail. Because several such fixation holes and thus alignable through holes are provided in the targeting device, these pairs of fixation holes and through holes can be provided with fixing elements one after the other, in principle two fixing elements are sufficient to enable clear and secure fixation of the targeting device relative to the fixation nail, the remaining pairs of through holes and fixation holes are then available for drilling holes in the bone fragments to be repositioned, with the drill being precisely aligned, since the through holes are used as target holes.

It is possible to successively cover different pairs of fixation holes and through holes with fixation elements, so that through this change successively different pairs of through holes and fixation holes are freed up for setting bone holes. This is possible because the fixation elements can be removed after the fixation in the fixation holes and after the axial fixation has been released.

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fixation in the target device can be pulled out of the target device to the rear.

The targeting device is therefore fixed relative to the fixation nail using fixing elements that change their position during the operation and thus enable the surgeon to work in different areas of the operation. Nevertheless, the targeting device and the fixation nail remain in a specific position relative to each other throughout the entire operation, which ensures that the through holes and the corresponding fixation hole are aligned in pairs.

It is particularly advantageous if fixation holes pointing in different directions are provided in the proximal end area of the fixation nail at different distances from the proximal end of the fixation nail, each of which is assigned a through hole in the targeting device that can be aligned with it. These fixation holes in the proximal end area of the fixation nail make it possible to attach the fixation elements in the proximal end area of the long bone, i.e. between the fracture fragments that can be folded down to the side. This enables a connection between the targeting device and the fixation nail without having to remove parts of the bone, for example without drilling out the bone head, the fixation nails can be pushed through between the bone fragments.

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In particular, it can be provided that two of the fixation holes lie in one plane and the other two run obliquely to this plane.

It is advantageous if the angle between the fixation holes running obliquely to the plane and the plane is equal in magnitude, but the fixation holes point to opposite sides of the plane. Such an arrangement has proven to be particularly advantageous, particularly with regard to penetration of the surrounding tissue by means of the fixation elements.

All fixation holes preferably run in planes that are perpendicular to the longitudinal axis of the fixation nail. However, it is also possible for these planes to be inclined relative to the longitudinal axis of the fixation nail.

The fixing elements can be fixed in the fixation holes in different ways, for example the fixing elements and the fixation holes could be locked together like a bayonet. In this case the fixing elements would have lateral projections that fit through a lateral recess in a fixation hole at a certain angular position of the fixing element, but which, after passing through the fixation hole, come to rest on the outside of the fixation nail by twisting the fixing element, thereby causing a locking.

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In a particularly preferred embodiment, the fixing holes for securing the fixing elements provided with an external thread have an internal thread. In this case, the fixing elements are screwed into these internal threads and are thereby secured in the defined screw-in position.

The internal threads of the fixation holes are usually threads that are designed similarly to the threads of bone screws, so that after the necessary holes have been drilled, bone screws can be screwed through these fixation holes, which are fixed both in the bone fragments and in the fixation nail by screwing.

Accordingly, the threads of the fixation elements are also adapted to the threads of bone screws, for example they have correspondingly high pitches. In order to speed up the screwing in process, it is particularly advantageous if the internal threads of the fixation holes are double threads, i.e. if there are two threads next to each other that are offset by 180° in the circumferential direction. This makes it possible to use relatively steep threads on the one hand, thus enabling rapid screwing in, but on the other hand to accommodate a large number of threads over a certain length of the thread hole in order to achieve optimal fixation of the fixation elements in the fixation hole.

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In order to ensure the reproducible insertion depth into the fixation holes, it can be provided that the fixing elements have stops that limit the insertion depth into the internal threads of the fixation holes; these can be formed, for example, by thickening the pin-shaped fixing elements.

It is also advantageous if the fixing elements have cylindrical shafts in the passage area through the through holes, as this allows them to be guided into the through holes without play over the entire length of the through holes, and only an axial fixing is then necessary to clearly fix the target device.

It is also advantageous if the inner diameter of the through holes is significantly larger than the inner diameter of the fixation holes. This enables the through holes to be used as target holes and thus enables drilling tools to be inserted through the through holes.

In a preferred embodiment, the fixing elements have removable stops that can be placed on the outer surface of the target device on the fixation nail side. These stops must be removable because otherwise a fixing element cannot be pulled out of a through hole, on the other hand, these stops are needed to ensure

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to enable axial fixation of the target device on the fixation element.

For example, the stops can be formed by projections that can be inserted laterally into recesses in the fixing element; for example, laterally insertable pins are conceivable here.

In a particularly preferred embodiment, the projections are the prongs of a fork-shaped stop which can be inserted into a circumferential groove of the fixing element. In this way, it is also very easy to remove this stop, as it is sufficient to pull the prongs out of the circumferential groove at the side.

Furthermore, it is advantageous if the fixing elements rest on the outer surface of the target device remote from the fixation nail by means of a clamping nut screwed onto the fixing element. The axial fixation can then be carried out simply by tightening this clamping nut, whereby the target device is clamped between the removable stop and the clamping nut.

In a preferred embodiment, the aiming device has a central post with through holes and arms projecting from the side thereof, which carry receiving sleeves for forming through holes. In this way, angularly rotated fixation holes can also be combined with through holes aligned with them.

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It is advantageous if additional through holes are arranged on the target device, which, when the target device is in a certain position relative to the fixation nail, are aligned with cross holes in the fixation nail that do not have an internal thread. By inserting fixation elements into these cross holes, the target device can be additionally fixed in the same way, but only against pivoting, not against the distance from the fixation nail.

It is advantageous if these transverse holes are arranged in the middle part of the fixation nail.

The transverse holes can be located in the same plane as two of the fixation holes.

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 perspective view of the repositioning instrumentation with an aiming device, a fixation nail and several fixation elements;

Figure 2: a sectional view along line 2-2 in Figure 1 with additional representation of a drilling tool;

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Figure 3: a representation similar to Figure 2 after fixing a first bone fragment to the fixation nail by screwing in a bone screw;

Figure 4: a sectional view taken along line 4-4 in Figure 3;

Figure 5: a view similar to Figure 3 after fixation of two bone fragments using bone screws;

Figure 6: a sectional view along line 6-6 in Figure 5 and

Figure 7: a schematic side view of a completely repositioned condyle with several bone fragments fixed to the fixation nail via bone screws.

The invention is explained below using the example of the repositioning of a humerus bone 1, which has a tubular middle part 2 and a spherical head. This head 3 is to be repositioned using the instrumentation of the present invention from several bone fragments 4, 5, 6. In principle, the described instrumentation can also be used on other bones that have a similar structure.

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The instrumentation used for this purpose comprises a shaft-shaped, straight fixation nail 7, which essentially has a proximal circular-cylindrical section which, approximately in the middle of the fixation nail 7, merges into a distal section which is also circular-cylindrical and has a smaller outer diameter.

In the proximal part of the proximal section 8 there are two fixation holes 10, 11 which run parallel to one another and diametrically penetrate the proximal section 8, of which the upper fixation hole 10 is arranged relatively close to the proximal end of the fixation nail 7, while the lower fixation hole 11 is arranged at a distance which corresponds to approximately one quarter of the proximal section 8.

Between the two fixation holes 10 and 11, two further fixation holes 12 and 13 are arranged, which penetrate the fixation nail 7 diametrically and are rotated by equal angles in opposite directions with respect to the plane spanned by the fixation holes 12 and 13; this angle can, for example, be in the order of 70°.

The fixation holes 10, 11, 12, 13 each have an internal thread 14, which can be designed as a double thread, i.e. using two parallel screw threads that are offset from each other by 180° in the circumferential direction.

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At the distal end of the proximal section 8, in the same plane as the fixation holes 10 and 11, two further transverse holes 15, 16 are arranged in the fixation nail 7, which also penetrate the nail 7 diametrically, but which do not have an internal thread but have a smooth inner wall.

Finally, two further transverse bores 17, 18 are provided in the fixation nail 7 at the distal end of the distal section 9, which lie in the same plane and penetrate the fixation nail 7 diametrically, but this plane is rotated with respect to the plane spanned by the fixation bores 10 and 11.

The instrumentation further comprises an aiming device 19 with a post 20 which is diametrically penetrated by several through holes 21, 22, 23, 24, which all lie in one plane and whose orientation and spacing is selected such that these through holes can be aligned with the fixation holes 10 and 11 and the transverse holes 15 and 16 in the fixation nail 7.

The mentioned through holes 21, 22, 23, 24 have a smooth inner wall and an inner diameter that is significantly larger than the inner diameter of the fixation holes 10, 11, 12, 13 and the transverse holes 15, 16, 17, 18.

A cross member 28 is held on the post 20 by a clamping screw 27 screwed into an internal threaded hole 26, which cross member 28 is arranged in two

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protruding arms 29, 30. Push-through sleeves 31, 32 are arranged at the free ends of these arms 29 and 30, the longitudinal axes of which form the same angle with respect to the longitudinal axes of the through-holes 21, 22, 23, 24 as the fixation holes 12, 13 form with respect to the fixation holes 10, 11. This makes it possible to arrange the post 20 relative to the fixation nail 7 at a distance at which the fixation holes 10, 11, 12, 13 are each aligned with the push-through holes 21 and 22 and the push-through sleeves 31, 32 which also form push-through holes. The push-through sleeves 31 and 32 are located at the respective height of the fixation holes 12 and 13 respectively.

This special position is described below as the target position, namely it is the position that the target device 19 should permanently assume relative to the fixation nail 7.

To achieve this, pin-shaped fixing elements 33 are used, which have a front cylindrical section 34 with a small outer diameter and a rear section 35 that is also cylindrical and has a larger outer diameter. At the front end, the front section 34 has an external thread 36, which is designed as a double thread and can be screwed into the internal thread 14 of the fixation holes 10, 11, 12, 13. The screw-in depth is limited by the length of the external thread 36, i.e. when the fixing element 33 is completely screwed in

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A defined screw-in depth is achieved in a fixation hole 10.

The rear sections 35 correspond with their outer diameter to the inner diameter of the transverse bores 15 and 16 as well as the through-holes 31 and 32, so that the fixing elements 33 can be pushed through this target device 19 from the side remote from the fixation nail and screwed into the corresponding aligned fixation bores 10, 11 and are then guided without play in the transverse bores 15, 16 or the through-holes 31, 32.

The rear sections 35 each have a circumferential groove 37 at their front end, into which the tines 38 of a fork-shaped spacer 39 can be inserted laterally such that the tines 38 penetrate into the circumferential groove 37 on opposite sides.

At the rear end of the rear section 35, a clamping nut 41 can be screwed onto an external thread 40, by means of which a fixing element 33 can be fixed in the axial direction relative to the post 20 or relative to the push-through sleeves 31, 32. When the clamping nut 41 is tightened, the spacer 39 is clamped against the opposite side of the post or the push-through sleeves 31 and 32, so that in this way the post 20 or the push-through sleeves 31, 32 are arranged at a precisely defined distance from the fixation nail 7, into which the fixing elements 33 are completely screwed.

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This makes it possible to position the target device 19 precisely relative to the fixation nail 7, and this position corresponds exactly to the desired position in which the fixation holes as well as the through holes and through sleeves are aligned with each other.

In addition to the fixing elements 33, fixing pins are also used which, similar to the fixing elements 33, have a front section 43 and a rear section, with the front section 43 being provided with an external thread 45 which can correspond to the external thread of a bone screw. However, the external thread 45 on these fixing pins 42 is longer than on the fixing elements 33, and the fixing pins 42 also lack a circumferential groove for receiving a spacer and an external thread for receiving a clamping nut.

Both the fixing elements 33 and the fixing pins 42 can have a receiving bore 46 for a screwing-in tool 47 at their end opposite the external thread 36 or 45 for the purpose of screwing in; this is shown only as an example in Figure 2.

In order to reposition the bone fragments 4, 5, 6 of the humeral bone 1 using the described instruments, the fixation nail 7 is first inserted into the tubular middle part 2 of the humeral bone 1, whereby the fixation holes 10, 11, 12, 13 in the

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area of the head 3. Fixing elements 33 are then screwed completely into the two fixation holes 10 and 11 between the bone fragments 4, 5, 6.

The aiming device 19 is pushed onto these two fixing elements 33 in such a way that the through holes 21 and 22 accommodate the two fixing elements 33. These are secured to the aiming device 19 by laterally pushing spacers 39 into the corresponding circumferential grooves 37 and by screwing on clamping nuts 41 in the axial direction. This positions the aiming device 19 in the desired position. The aiming device 19 can also be attached to the fixation nail 7 by screwing the fixing elements 33 through the through holes 21, 22 or the sleeves 31, 32 into the fixation nail. This procedure is used if the aiming device cannot be pushed onto the fixing elements 33 because the oblique fixation holes 12, 13 are primarily to be used.

For additional security, two fixing pins are passed through the through hole 23, 24 and screwed with their external thread 45 through the middle part 2 of the humeral bone 1 and through transverse holes 15 and 16. For this purpose, a bone hole is prepared in the middle part 2, namely with the help of a drilling tool 48, which is pushed through a through hole 23 acting as a drilling jig and then precisely aligns the bone hole

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with: the transverse bore 15 in the fixation nail 7 (Figure 2).

The same procedure is followed for the transverse bore 16 and the through bore 24.

Now the positioning of the first bone fragments 4, 5 can begin. These are arranged relative to the fixation nail 7 in the way they are to be secured to it later. Then, using the drilling tool 48, which is pushed through the push-through sleeve 31 and the fixation hole aligned with it, a hole for receiving a bone screw is made in the bone fragments 4, 5. The bone fragments 4, 5 can then be secured to the fixation nail 7 by screwing a bone screw 49 into the hole created in this way. This process is illustrated in Figures 3 and 4.

Another bone screw should then be passed through the upper fixation hole 10, for example. To do this, the fixation element 33 fixed in this fixation hole 10 must first be removed. This is done by loosening the corresponding clamping nut 41 and removing the corresponding spacer 39. The fixation element 33 can then be unscrewed from the fixation hole 10 and then pulled out of the post 20 of the target device 19 through the through hole 21. To securely fix the target device 19, the fixation element removed in this way is

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The fixing element 33 is then screwed into the fixation hole 13, for example. For this purpose, it is first pushed through the push-through sleeve 32 and then, after being screwed into the fixation hole 13, is secured in the axial direction by inserting a spacer 39 and screwing on a clamping nut 41, so that the target device 19 is again securely connected to the fixation nail 7 via two fixing elements 33. After appropriate positioning of a further bone fragment 6, a new hole can now be made through the fixation hole 10 which has then become free, which leads through the fixation hole 10, and a further bone screw 50 can be screwed into this bone hole.

The other holes for bone screws, which are to be inserted through the fixation holes 11 and 13, can then be made in the same way, whereby any interfering fixation elements 33 are removed. The fixation of the target device 19 is then only carried out by a fixation element 33 and the two fixation pins 42 (Figures 5 and 6).

Finally, all bone holes created in this way can be filled with bone screws so that the individual bone fragments 4, 5, 6 are optimally screwed to the fixation nail 7; an additional screwing of the fixation nail 7 to the middle part 2 of the humeral bone 1 can then also be carried out; the threaded holes required for this are already prepared by the fixation pins 42.

Claims (18)

1. Repositioning instrument for fragment fractures of long bones with a shaft-shaped fixation nail that can be inserted into the long bone and has transverse fixation holes and with a target device that can be connected to the nail via fixation elements, characterized in that pin-shaped fixation elements ( 33 ) can be reproducibly inserted into several fixation holes ( 10 , 11 , 12 , 13 ) and can be fixed in this position, that the target device ( 19 ) has several through holes ( 21 , 22 , 31 , 32 ) for receiving such fixation elements ( 33 ) essentially without play, that the fixation holes ( 10 , 11 , 12 , 13 ) and the through holes ( 21 , 22 , 31 , 32 ) are arranged in such a way that in a certain position of the target device ( 19 ) relative to the fixation nail ( 7 ), a fixation bore ( 10 , 11 , 12 , 13 ) and a through-bore ( 21 , 22 , 31 or 32 ) are aligned with one another at the same time, that the fixing elements ( 33 ) in the through-bores ( 21 , 22 , 31 , 32 ) can be fixed in the axial direction in such a way that the target device ( 19 ) can be fixed in this specific position relative to the fixation nail ( 7 ) when the fixing elements ( 33 ) are inserted into the fixation bores ( 10 , 11 , 12 , 13 ) and fixed in these, and that the pin-shaped fixing elements ( 33 ) after releasing this fixation and releasing the fixing in the fixation bores ( 10 , 11 , 12 , 13 ) can be pulled out of the through holes ( 21 , 22 , 31 , 32 ) of the aiming device ( 19 ). 2. Instruments according to claim 1, characterized in that in the proximal end region of the fixation nail ( 7 ) at different distances from the proximal end of the fixation nail ( 7 ) fixation bores ( 10 , 11 , 12 , 13 ) pointing in different directions are provided, each of which is assigned a through-bore ( 21 , 22 , 31 or 32 ) of the target device ( 19 ) that can be aligned with it. 3. Instruments according to claim 2, characterized in that two of the fixation bores ( 10 , 11 ) lie in one plane and the other two fixation bores ( 12 , 13 ) run obliquely to this plane. 4. Instruments according to claim 3, characterized in that the angle between the fixation holes ( 12 , 13 ) running obliquely to the plane and the plane is equal in magnitude, but the fixation holes ( 12 , 13 ) point to opposite sides of the plane. 5. Instrumentation according to one of the preceding claims, characterized in that all fixation bores ( 10 , 11 , 12 , 13 ) run in planes which are perpendicular to the longitudinal axis of the fixation nail ( 7 ). 6. Instrumentation according to one of the preceding claims, characterized in that the fixation bores ( 10 , 11 , 12 , 13 ) have an internal thread ( 14 ) for securing the fixing elements ( 33 ) provided with an external thread ( 36 ). 7. Instruments according to one of the preceding claims, characterized in that the internal threads ( 14 ) of the fixation bores ( 10 , 11 , 12 , 13 ) are double threads. 8. Instrumentation according to one of the preceding claims, characterized in that the fixing elements ( 33 ) have stops which limit the screw-in depth of their threads ( 36 ) and the internal thread ( 14 ) of the fixation bores ( 10 , 11 , 12 , 13 ). 9. Instrumentation according to one of the preceding claims, characterized in that the fixing elements ( 33 ) have cylindrical shafts in the passage area through the through openings ( 21 , 22 , 31 , 32 ). 10. Instruments according to one of the preceding claims, characterized in that the inner diameter of the through holes ( 21 , 22 , 31 , 32 ) is substantially larger than the inner diameter of the fixation holes ( 10 , 11 , 12 , 13 ). 11. Instrumentation according to one of the preceding claims, characterized in that the fixing elements ( 33 ) carry removable stops ( 39 ) which can be placed on the outer surface of the target device ( 19 ) on the fixation nail side. 12. Instruments according to claim 11, characterized in that the stops ( 39 ) are projections ( 38 ) which can be inserted laterally into recesses ( 37 ) of the fixing element ( 33 ). 13. Instruments according to claim 12, characterized in that the projections are the prongs ( 38 ) of a fork-shaped stop ( 39 ) which can be inserted into a circumferential groove ( 37 ) of the fixing element ( 33 ). 14. Instrumentation according to one of claims 11 to 13, characterized in that the fixing elements ( 33 ) rest on the outer surface of the target device ( 19 ) remote from the fixation nail by means of a clamping nut ( 41 ) screwed onto the fixing element ( 33 ). 15. Instrumentation according to one of the preceding claims, characterized in that the aiming device ( 19 ) has a central post ( 20 ) with through holes ( 21 , 22 ) and arms ( 29 , 30 ) projecting laterally from this, which carry receiving sleeves ( 31 , 32 ) for forming through holes. 16. Instrumentation according to one of the preceding claims, characterized in that further through-bores ( 23 , 24 ) are arranged on the target device ( 19 ), which, in the specific position of the target device ( 19 ) relative to the fixation nail ( 7 ), are aligned with transverse bores ( 15 , 16 ) in the fixation nail ( 7 ) which do not have an internal thread. 17. Instruments according to claim 16, characterized in that these transverse bores ( 15 , 16 ) are arranged in the middle part of the fixation nail ( 7 ). 18. Instrumentation according to one of claims 3 to 17, characterized in that the transverse bores ( 15 , 16 ) lie in the same plane which is spanned by two of the fixation bores ( 10 , 11 ).