Implantation system and target device therefor

IS 2 280 643 T3

DESCRIPTION

Implant system and guidance apparatus for it.

The invention relates to an implant system according to claim 1.

Locking nails for long bone fracture repair are widely used. Its use is described in "The Journal of Trauma" 1993, vol. 35, pages 772 to 775. These locking nails are characterized by the arrangement of two transverse holes at one end (eg the distal end) and at least one transverse hole at the other end (eg the proximal end). Bone screws are passed through the transverse holes and threaded into opposite sides of the cortex. In this way, the locking nail is secured axially and against rotation.

In the use of this type of locking nail, the position of the transverse holes or locking holes in the locking nail has to be identified, in order to be able to drill in the correct place in the cortex from the outside. To this end, a series of guiding apparatuses has been disclosed which normally work with X-rays to determine the position of the transverse holes with respect to the guiding apparatus. If this is the case, with the aid of the guiding apparatus and what is called a drill sleeve or guide, the bone is drilled in the correct place, so that the bone screws can be screwed in. Known guiding appliances are often attached to one end (eg the proximal end) of the nail. Thus, the arrangement of the locking holes relative to the guide holes in the guide apparatus is roughly predetermined. However, it must be taken into account that, due to the curvature of the bone and the possible twisting of the nail when it is inserted, the assumed position of the locking holes may not coincide with the real one.

For this reason, until now it has not been possible to carry out an exact identification of the position of the locking holes solely by mechanical means.

From WO01 / 60272-A1 a locking nail has been known in which there is only one slot, parallel to the axis, formed in the nail shaft in the distal section of the area of ​​the locking holes. The radial axis of the groove sections the axis of the hole approximately perpendicular. Also described in the cited patent is a guiding apparatus, the guiding arm of which has two guiding holes. The guide holes are formed in a section of the guide arm of the guide apparatus, which yields elastically. With the aid of a fine rod-shaped probe, the actual position of the nail in the bone is determined with the aid of the locking holes and the slot between them. By rotating the nail and moving it axially, it is possible to determine when the probe is in the area of ​​a locking hole.

From WO96 / 03085 it is known the method of inserting a locking nail, which houses an adapter, into a connecting element which is housed in a rigid guide arm of a guide apparatus so that it can be axially displaced and rotatable.

It has been found that this purely mechanical procedure still creates problems for the surgeon, since the surgeon cannot always determine with sufficient precision the actual position of the nail by actuating the probe.

Therefore, the invention aims to create an implant system or a guiding apparatus with which the position of the locking holes can be easily determined and the holes placed in the bone in the correct place.

This objective is achieved by the features of claim 1.

The locking nail in the implant system according to the invention has means with the help of which the position of the locking holes can be found. One means consists, for example, in providing a slot parallel to the axis between the locking holes. Another possibility is to provide peripheral grooves or, alternatively, suitable stops in the area of ​​the locking holes, which can be detected with the aid of a probe.

The particularity in the system according to the invention, however, resides in the guide apparatus, in such a way that the guide arm is rigidly shaped and has a guide section in which three guide holes are provided. The axes of the guide holes are located in a plane that runs along the longitudinal axis of the guide arm or parallel to it. The distance of the outer pilot holes corresponds to the distance of the locking holes. The central guide hole can be located anywhere between the outer guide holes, for example, half way apart.

The locking nail can be detachably attached with a nail adapter, for example by a suitable threaded joint. The nail adapter can be detachably attached with a connecting element which, in turn, can be detachably attached with the rigid guide arm. The detachable connection of the nail adapter to the guide arm allows the use of the guide apparatus according to the invention for a wide variety of different locking nails, without requiring a guide apparatus for each type of locking nail. By adjusting the adapter on the one hand and the guide arm on the other, the nail can be adjusted relative to the guide arm prior to implantation. This happens simply because, for example, with the aid of a caliper bolt, the outer guide holes of the guide section of the guide arm are aligned with the locking holes of the nail. The nail can then be implanted, allowing the nail adapter to be held in the nail. The locking nail can continue to be inserted into its final position or without reaching the desired final position. The guiding apparatus is then reassembled and the corresponding cortex is drilled through the central guiding hole. The targeting apparatus is then detached from the nail adapter again and a rod-shaped probe is inserted into the bone through the bore. The probe will hit the closed wall of the locking nail and, in the best case, for example, will enter the slot that joins the locking holes. By turning the nail, it is possible, for example, to find the groove and determine that it is really the groove. The nail is then removed or continued to be inserted until the probe interacts with the assigned locking hole. The guiding apparatus is then reassembled and one of the outer guiding holes is aligned with the found locking hole. Different possibilities can be devised for this. Preferably, a fixing sleeve will be used that has a front section whose diameter corresponds to the diameter of the locking hole and another

ES 2 280 643 T3 section whose diameter corresponds to the guide hole. The inside diameter of the fixation sleeve is dimensioned so that it can be inserted over the rod-shaped probe that is still in the locking hole and the hole drilled in the bone. In this way, a fairly precise alignment of a guide hole with a locking hole can be obtained, by reassembling the guide arm and inserting its guide hole over the fixing sleeve. Once this is done, also the second guide hole in the guide arm will be aligned with the second locking hole, allowing the cortex to be drilled through the second locking hole in the known way, so that it can then be insert the locking screw. After the first lock is made, the second lock can be performed by also drilling the cortex in the known manner through the guide hole through which the alignment was made, and thus inserting the second locking screw.

As already mentioned, the locking nail has in the area of ​​the locking holes means with which the perception of the nail and palpation of a locking hole are facilitated.

In theory, however, it could also be conceivable to dispense with such means, but only when the locking nail has not been twisted as it is inserted around the diameter of the locking hole. If this is the case, then the surgeon will not know how far the nail should be removed or inserted until the axial position of the locking hole is reached.

For the calibration, it is provided according to the invention that the guide section is housed rotatably about an axis perpendicular to the longitudinal axis of the guide arm and that it has first fixing means for determining the guide section in a rotational position. specified. The axis of rotation is housed on the axis of the guide hole that is closest to the other end of the nail.

According to one embodiment of the invention, the guide section has a groove parallel to the axis in the region of the guide holes, which extends perpendicular to the axis of the guide holes and which divides the guide section into a narrow section and a wide. In this way, when inserting a caliper bolt, drill sleeve or the like, a tightening effect is obtained, so that these parts will not be able to move or fall unintentionally.

According to one configuration of the invention, calibration is further facilitated if the nail adapter is mounted rotatably about its longitudinal axis on the connecting element and two fixing means are provided to determine the relative rotational position. According to another configuration of the invention, between the connecting element and the adapter, adjustment means are provided for adjusting the relative rotational position. The adjusting means may contain, for example, an adjusting screw or the like.

The rigid guide arm of the guide device according to the invention is preferably shaped in the form of an elongated rod with a non-circular section, which is inserted in a complementary opening of the connecting element, a wall of the opening being formed by a clamping element that can be actuated by a clamping screw. In this way, the connecting element can be continuously adjusted on the guide arm in the axial direction, the rotary position remaining unchanged. Other configurations are indicated in the dependent claims of the invention.

The invention is explained in more detail below with the aid of drawings.

Fig. 1 is a side view of a guide apparatus according to the invention.

Fig. 2 is a 90 ° rotated side view of the guide apparatus according to FIG. 1.

Fig. 3 is a perspective representation of the guide apparatus according to Figures 1 and 2.

Fig. 4 shows the end of the guide arm of the guide apparatus according to Figures 1 to 3.

Fig. 5 shows an end view of a guide section of the guide apparatus according to Figures 1 to 3.

Fig. 6 shows a section through the representation according to fig. 5 along line 6-6.

Fig. 7 shows an end view rotated by 90 ° of the guide section according to fig. 5.

Fig. 8 is a perspective of the connection and calibration element of the guide apparatus according to figures 1 to 3.

Fig. 9 shows the connecting element of the arrangement according to fig. 8.

Fig. 10 shows a section through the connecting element according to fig. 9.

Fig. 11 is a side view of the gauge and connection element according to fig. 8.

Fig. 12 shows a detail of the arrangement according to fig. eleven.

Fig. 13 is a side view of the gauge bolt.

Fig. 14 is a side view of a probe.

Fig. 15 is a 90 ° rotated side view of the probe according to FIG. 14.

Fig. 16 is a side view of a clamp sleeve.

Fig. 17 is a side view of a locking nail, as well as a nail adapter attached thereto.

Fig. 18 shows the end of a nail in another embodiment.

Fig. 19 shows another embodiment of one end of the locking nail.

Fig. 20 is a side view of a nail adapter for the system according to the preceding figures.

In Figures 1 to 3 a guide arm 10 is seen having a square cross section. At the left end of the guide arm 10 is housed a gauge and connection element 12, and at the right end a guide section 14 is seen which is rotatably housed on an appropriate support section 16 of the right end of the guide arm 10 .

The locking nails for which the guiding apparatus according to Figures 1 to 3 can be used are indicated in a hinted way in Figures 17 to 19. In Figure 17 a locking nail 20 is seen, for example a locking nail femur. At the distal end it has two axially spaced locking holes 22, 24 and at the proximal end a locking hole 26. Between the locking holes 22, 24 extends a slot 28 parallel to the axis with a section in the shape of, for example, U or V. The diameter of the locking holes 22 to 26 is identical. In the example shown, the proximal end of locking nail 20 is attached to an elongated nail adapter by means of a screw 32 that can be screwed into the proximal end of nail 20. The nail adapter has flattening at the other end. 34 opposites.

In fig. 18 shows the end of a locking nail 43 with holes 40, 41 and slots

IS 2 280 643 T3

50, 52 peripheral in the area of ​​the locking holes 40, 41. In fig. 19, locking holes 41, 40a are shown which are formed in a reduced diameter distal end section of locking nail 43a. To the left of the locking holes 40a, 41a there are respectively formed collars 56, 58 radial in diameter, in which the collar 58 is chamfered towards the left end. The function of the displayed nail configurations will be explored further below.

As can be seen especially in Figures 5 to 7, the guide section 17 has three guide holes 60, 62, 64 whose axes are located in a plane that runs along the longitudinal axis of the guide arm 10 or parallel to it. The center-to-center distance of the outer guide holes 60, 64 corresponds to the distance of the locking holes 22, 24 or 40, 41 or 40a, 41a. As is clear from Figures 6 and 7, the guide section 14 has a relatively wide first slot 66, the width of which is slightly greater than the width of the support section 16. As can be seen from fig. 4, the support section is fork-shaped with arms 70, 71 having a flare 72 between each other near the ends of the arms 70, 71 and an arc-shaped groove 74 at the end of the arms 70, 71 which runs transversely. From Figures 6 and 7 it can be seen that the groove 66 is traversed by the shank of a fixing screw 76, the diameter of the shank being slightly less than the width of the arc-shaped groove 74 of the bearing section 16. At the inner end, the slot 66 is traversed by a support sleeve 68. If the bearing section 16 is inserted into the slot, the shank of the set screw 76 reaches into the arc-shaped slot 74 and the sleeve 68 into the flare 72. Thus, the guide section 14 is housed in the bearing section 16 rotatably about the axis of the sleeve 68. The set screw 76 determines the relative rotational position.

By means of the relatively narrower slot 78, which is made from the free end of the guide section 14, the guide section 14 is divided into a relatively wide section 80 having the slot 66 and a relatively narrower section 82. The latter is limitedly elastic with respect to the former and has holes that are aligned with the guide holes 60 to 64.

FIGS. 8 to 10 show a connecting element 84 with the help of which the nail adapter can be held adjustable and detachable in the guide arm 10, for example according to FIG. 17. The connecting element 84 has a square opening 86 with a cross section corresponding to the cross section of the guide arm 10. A clamping section 88 is movably housed in the connecting element 84 and forms an angular section of the opening 86. Section 88 is driven by a set screw 90 which acts on a relatively thin section 92 which is separated from the remaining section 88 by means of a slot, in order to achieve an elastic effect. A pin 94 that is housed in a slot in section 88 limits regulation of section 88.

The connecting element 84 also has a support sleeve 96 whose axis runs perpendicular to the axis of the housing opening 86. A groove 98 is formed in the bearing sleeve 96 which has some extension in the peripheral direction.

In addition, a pin 100 is incorporated in a press fit that protrudes slightly from the interior of the support sleeve 96.

In fig. 11 shows the other side of the gauge and connection element according to FIG. 8 in a side view. In fig. 12 a sleeve section 102 is seen having a slot 104 partially extending in the peripheral direction. The sleeve section 102 is dimensioned so that it can be inserted into the support sleeve 96, with the grooves 98 and 104 being able to be at least partially covered. At one end of the sleeve section there is positioned an arm 106 which at 108 rotatably houses an adjusting screw 110 which is fitted with a cylindrical handle 112 having an internal thread. The actuation of the screw 110 is carried out by means of a rotary knob 114. Opposite the arm 106, at the same end of the sleeve section 102, an arm 116 is formed having an arcuate slot 118, open to one side. Within the sleeve section 102 there is another sleeve section 120 in which an arm 122 is formed. At the free end of the arm 122 a circular recess 124 is formed, which houses the round handle 112. Rotating knob 114 also produces relative rotation between arms 108 and 122. A knob 126 drives a set screw 128 which engages a threaded hole, not shown, in sleeve section 120. Screw shank 128 here extends through slots 98 and 104 of support sleeve 96 and sleeve section 102. Sleeve section 120 has a non-circular opening 130 for housing the end section of nail adapter 30. With the aid of the set screw 128, the axial position of the nail adapter in the opening 130 can be determined. By rotating the arm 122 relative to the link member 84, the nail adapter can be rotated about its axis and the nail 20 rotated. The relative rotational position of the sleeve section 102 or arms 106 and 116 with respect to the connecting element 84 it is produced by means of the fixing screw 90, the stem of which extends through the arcuate slot 118.

In fig. 13 shows a gauge bolt 132 with a smaller diameter left section 134 and a relatively long larger diameter section 136. The diameter of the section 134 corresponds to the diameter of the locking holes 26, 24 or 40, 41 or 40a, 41a. The diameter of section 136 corresponds to the diameter of guide holes 60, 62 or 64.

Figures 14 and 15 show a probe having a relatively small diameter circular cross section over its entire length, which is clearly smaller than the diameter of the locking holes. At one end, probe 138 is chamfered, as shown at 140, to form a kind of cutting edge. At the other end, probe pin 138 has opposing flats 142 for clamping in a grip section (not shown).

In fig. 16 shows a clamping sleeve 144 with a section 146 whose outer diameter corresponds to the diameter of the locking holes 22, 24 or 41,40,41a, 40a. A section 148 has a larger diameter that corresponds to the diameter of the guide holes 60-64. At the far right, the guide sleeve 144 is equipped with a clamp section 150 for separable attachment.

ES 2 280 643 T3 with a handle. The guide sleeve 144 has an axial through hole with a diameter such that the probe pin 138 can be inserted almost perfectly therein.

The nail adapter 160 shown in FIG. 20 has a stem 162 the cross section of which is complementary to the cross section of the opening 130 in the connecting element 84 (see, for example, FIG. 8). At the left end of the stem 162 there is positioned an adapter section 164 with the aid of a screw joint not shown. At its free end it has two projections 166 which engage in corresponding recesses in the nail (not shown here) to predefine its position of rotation. Then, the nail is fixed in the adapter 160 with the aid of a screw joint that passes through the hollow section 164.

At 168 or 170 holes are hinted through stem 182 which can also be used as guide holes.

The implant system described is used as follows. Calibration is carried out first. The nail to be implanted, for example nail 20 according to FIG. 17, is attached to the nail adapter 30. The nail adapter 30 is inserted into the opening 130 of the connecting element and is fixed with the aid of the set screw 126. By axially adjusting the connecting element 84 on the guide arm 10 and, in a given case, by rotating the nail by actuating the set screw 114, the locking holes 22, 24 are aligned with the guide holes 60, 64 . An alignment with respect to the guide hole 60 is first made by inserting a gauge bolt according to FIG. 13. A drill guide sleeve and a drill can optionally also be used for this. Here, section 134 of gauge 132 reaches into locking hole 22. The guide section 14 is then rotated until the guide hole 64, 84 is also aligned with the locking hole 24, which can be determined with the aid of the gauge bolt. Then a fixation of the guide section 14 is also carried out in the rotated position taken with the aid of the fixation screw 76. The position of the nail was previously fixed by the set screw 126, the set screw 90 and the set screw 114. The nail adapter 30 is then removed by loosening the set screw 126 and the locking nail 20 is inserted into the bone in the usual manner, eg, proximally in the femoral canal. Nail adapter 30 remains attached to locking nail 20. The locking nail 20 is continued to be inserted a certain course beyond the desired final position. This excess corresponds to a path that is less than the distance of the locking holes 22, 24. After inserting the nail, the guide arm 10 is fastened to the nail adapter 30 in the manner already described. A hole is now drilled in the corresponding cortex of the bone through the central guide hole 62 with the aid of an appropriate drill sleeve and, in a given case, a tissue protective sleeve. In this case, the drill must be prevented from coming into contact with the nail 20. Once it has been made, the guiding apparatus is removed from the nail adapter and, with the aid of the probe 138 which is inserted through the hole in the bone, an attempt is made to palpate slot 28. If this is not the case, by slightly rotating the nail 20 in the bone canal, the slot 28 can be palpated. As soon as this is the case, the nail 20 is withdrawn slightly until the probe 22 palpates the locking hole 24. If this is the case, the fixation sleeve 144 is inserted over the probe 138. Here, the section 146 reaches into the locking hole 24 through the hole in the bone. With the locking sleeve 144 inserted in this manner, the guide apparatus is reassembled, the guide hole 64 aligning with the fixation sleeve 144. When the fixing of the guide apparatus has been made, the inner guide hole 60 will automatically be aligned with the inner locking hole 22. The bone can now be drilled on the opposite sides of the locking hole 22 with conventional procedures and a locking screw inserted to fix the nail in the bone. When this has been done, by removing the fixation sleeve 144 and with the aid of conventional procedures, the cortex can also be drilled on the other side, thus also inserting a locking screw on this side.

As soon as the distal locking has been completed, a locking in the region of the proximal locking hole 26 can also be performed in known manner.