Height-adjustable implant to be inserted between vertebral bodies and corresponding handling tool

p0001The invention relates to a height-adjustable implant for insertion between vertebral bodies.

p0002One for example <patcit id="pcit0001" dnum="DE19622827A1"><text>DE 196 22 827 A1</text></patcit> Has a first and a second sleeve part, the second sleeve part carrying an external thread which is rotationally fixed with a longitudinal section in the first sleeve part and axially movably engages the longitudinal part protruding from the first sleeve part from a nut engaging into the external thread . By rotating the nut, the second sleeve part is moved out of the first sleeve part. To actuate the nut, a rod-shaped handling tool with its free end is inserted into a recess on the outer circumference of the nut. By means of a pivoting movement of the tool in a plane extending transversely to the longitudinal axis of the implant, the nut is further rotated by a part corresponding to the pivot angle of the tool. Then the tool ' Is withdrawn from the nut and the process described is repeated until the implant has the required height. During the rotary actuation of the nut, the first sleeve part must not rotate, so that this must normally be held with a further tool. The height adjustment in the known implant thus requires an increased expenditure of time and equipment. In addition, a relatively large operating opening is necessary in order to be able to make the said manipulations without hindrance The height adjustment in the known implant thus requires an increased expenditure of time and equipment. In addition, a relatively large operating opening is necessary in order to be able to make the said manipulations without hindrance The height adjustment in the known implant thus requires an increased expenditure of time and equipment. In addition, a relatively large operating opening is necessary in order to be able to make the said manipulations without hindrance

p0003Out <patcit id="pcit0002" dnum="US2003045877A"><text>US 2003 / 045877A</text></patcit> A height-adjustable implant according to the preamble of claim 1 is known.

p0004The <patcit id="pcit0003" dnum="DE10065232A1"><text>DE 100 65 232 A1</text></patcit> Shows in the <figref idrefs="f0002 f0003 f0004 f0005 f0006">FIGS. 2-8</figref> (2), wherein the second sleeve part (3) carries an external thread (6), which rotates with a longitudinal section in the first sleeve part (2), and wherein the first sleeve part (2) (4), which engages into the external thread (6), and which has a toothed ring (7), which is arranged on the outside of the first sleeve part (2) by the interaction of the guide slots (8) with the pins (9) ).

p0005Printed copy <patcit id="pcit0004" dnum="JP2261446A"><text>JP 2-261446</text></patcit> Shows a height-adjustable implant for insertion between the vertebral body and two implant parts 9, 14 whose height adjustability is ensured by an external thread 10 which is assigned to the one implant part 14 and into which a length-adjusting ring 19 having a bevel gear teeth engages. This length-adjusting ring 19, which corresponds to the nut, is fixed by an axially effective stopper (20) on the first sleeve part, which limits the movement of the length-adjusting ring (19), that is, the nut, in the longitudinal direction.

p0006It is the object of the invention to propose an implant and a handling tool with which the insertion into the spinal column is facilitated.

p0007This object is achieved by the subject matter of claim 1.

p0008According to claim 1, the nut carries a toothed ring, that is to say is designed as a toothed wheel. The height of the implant can be adjusted by means of a tool with a suitable counterelement, for example a drive gear wheel, whereby no swivel movements have to be carried out with the handling tool. Moreover, it is not necessary to implement the tool many times. It can be kept in the same position during the whole process of the height adjustment, which considerably simplifies the operation and saves operation time.

p0009In a preferred embodiment, the nut carries the tooth ring on its lower side facing the first sleeve part. The actuation of the nut can thereby be effected by means of a drive gear wheel whose axis of rotation runs at right angles to the axis of rotation of the nut. A deflection of the rotational movement of the axle, as would be the case with a drive gear wheel with an axis parallel to the axis of rotation of the nut, is not necessary, which promotes a compact design and reduces the production effort.

p0010In order to ensure a rotational fixing of the first sleeve part, a threaded bore is provided on the sleeve part, on which a handling tool driving the nut can be fixed. In contrast to conventional implants, therefore, only a single tool is used which serves both to drive the nut and to fix the first sleeve part.

p0011At the out <patcit id="pcit0005" dnum="DE19622827A1"><text>DE 196 22 827 A1</text></patcit> The nut is supported on the end face of the first sleeve part when the second sleeve part is extended. Otherwise, however, the nut is not fixed to the first sleeve part. The height of the known implant can therefore only be increased, but not reduced, ie the second sleeve part can not be inserted into the first sleeve part. In the implant according to the invention, on the other hand, the nut is fixed to the first sleeve part by means of an axially effective positive connection, that is to say in both axial directions, as a result of which both an enlargement and a reduction in the height of the implantation is possible. The latter may, for example, be necessary if an excessive adjustment of the height has been made after the implant has been inserted.

p0012In the invention, the two sleeve parts have axially running windows opening out in their mutually facing ends, the peripheral sections arranged between two adjacent windows being axially displaceable in the windows of the respective other sleeve part. Compared to an arrangement in which two sleeve parts engage concentrically, this initially has the advantage that less material is required and the implant is thereby made lighter overall. In addition, a substantially larger interior space is available which is provided with bone material or the like, Can be filled. As a result of the comb-like intermeshing of the two sleeve parts, a mutual rotational fixation is finally ensured.

p0013A radially widened end plate is preferably provided for supporting the implant on a vertebral body. In a preferred embodiment, this is a separate, releasably fixed part. In each individual case, the suitable end plate, for example a plane which runs obliquely with respect to the central longitudinal axis of the implant, can then be used. If the end plate is fixed to the sleeve part by means of a snap connection, on the one hand a secure hold on the sleeve part is ensured, and on the other hand an easy interchangeability. The simple construction according to the invention, which is simple in terms of manufacture and assembly, provides that an annular groove is provided near the end face in the inner wall of the sleeve part into which latching lugs formed on the underside of the end plate engage.

p0014A handling tool for an implant of the type described above has, according to claim 10, a toothed wheel cooperating with the nut. Preferably, a holding device for holding the implant is provided on the handling tool. The gear wheel is arranged in such a way that its axis, when driven, runs transversely with respect to the axis of the gear ring of the nut. A deflection of the rotational movement of the drive axle is, as already mentioned above, not required. A particularly space-saving and easy-to-operate arrangement provides that the tooth ring is arranged on the end face of a pipe section, and that the pipe section is penetrated by a rod whose free end projects out of the pipe section and can be screwed into the threaded bore of the first sleeve part.

p0015The invention will now be described in more detail with reference to the accompanying drawings. Show it:<dl id="dl0001"><dt>FIG</dt><dd>A partially cut-away perspective view of an implant with a first sleeve part and a second sleeve part axially movable therein, the second sleeve part being in its retracted position,</dd><dt>FIG</dt><dd>The implant of <figref idrefs="f0001">FIG</figref> With a partially extended second sleeve part,</dd><dt>FIG</dt><dd>A perspective view of the first sleeve part,</dd><dt>FIG</dt><dd>A perspective view of the extendable second sleeve part,</dd><dt>FIG</dt><dd>A nut serving to drive the first sleeve part,</dd><dt>FIG</dt><dd>A front plate fixable to a sleeve part,</dd><dt>FIG</dt><dd>A tool for handling the implant.</dd></dl>

p0016The implant shown in the figures has as main components a first sleeve part 1, a second sleeve part 2 and a nut 3. The sleeve part 2 is provided with an outer thread 4 which extends essentially over its entire length. Both sleeve parts 1, 2 have axially extending windows 6, which in their assembled state open into their facing end faces 5a, b. The circumferential sections 7a, b remaining between two adjacent windows are axially displaceable in the windows 6 of the respective other sleeve part 1, 2. In this case, the clearance between the circumferential sections 7a, b is dimensioned in such a way that a shackle-free seat of the nevertheless two sleeve parts can be fitted into each other and easy to move. The sleeve parts 1, 2 have approximately the same wall thickness and the same inner diameter, ie the circumferential sections 7b of the second sleeve part 2 do not extend beyond the outer circumference or the inner circumference of the sleeve part 1. The axial length of the windows 6 or of the circumferential sections 7a, b is such that an axial distance 9 is present between the end faces 5a, b of a circumferential section 7a, b and the base 8 of a sleeve section 1,

p0017The nut 3, which comprises both sleeve parts 1, 2, serves to adjust the height and to retract and extend the sleeve part 2. It is axially fixed and rotatably connected to the first sleeve part. The inner side thereof, which comprises the two sleeve parts 1, 2, has an upper longitudinal section, which is provided with an internal thread 10, and a longitudinal section 13, An annular groove 14 is machined into these. The nut 3 is positioned on the sleeve part 1 in such a way that only the thread-free longitudinal section 13 comprises the circumferential sections 7a of the sleeve part 1 and the internal thread 10 engages with the external thread 4 of the sleeve part 2. Near the end face 5a of a circumferential section 7a is formed a circular segment-shaped projection 15 extending over its entire width, Which engages in the annular groove 14 of the nut. Although the nut 3 can rotate on the sleeve part 1, it is fixed to the latter in both axial directions. The side of the nut 3 facing the free ends of the circumferential sections 7b carries a toothed ring 17 extending coaxially with the center longitudinal axis 16 of the implant. The toothed ring 17 is integrally formed, for example milled, on the nut 3. It is used to rotate the nut 3 by means of a tool to be described in more detail below, and thereby to move the sleeve part 2 out of the sleeve part 1 or into the latter, that is to say to adjust the height of the implant. The side of the nut 3 facing the free ends of the circumferential sections 7b carries a toothed ring 17 extending coaxially with the center longitudinal axis 16 of the implant. The toothed ring 17 is integrally formed, for example milled, on the nut 3. It is used to rotate the nut 3 by means of a tool to be described in more detail below, and thereby to move the sleeve part 2 out of the sleeve part 1 or into the latter, that is to say to adjust the height of the implant. The side of the nut 3 facing the free ends of the circumferential sections 7b carries a toothed ring 17 extending coaxially with the center longitudinal axis 16 of the implant. The toothed ring 17 is integrally formed, for example milled, on the nut 3. It is used to rotate the nut 3 by means of a tool to be described in more detail below, and thereby to move the sleeve part 2 out of the sleeve part 1 or into the latter, that is to say to adjust the height of the implant.

p0018The end faces 18 facing away from the free ends of the circumferential sections 7a, b bear an end plate 19 which extends radially beyond the circumference of the sleeve parts 1, 2. The end plates 19 are detachably fixed to the sleeve parts 1, 2 by means of a snap-fit ​​connection. For this purpose, an annular groove 20 is provided on the inside of the sleeve parts 1, 2 near their end faces 18, into which latching projections 23 arranged on the side of the end plate facing the end faces 18a, b. The detent projections 23 are formed on an apron 24, which surrounds a central opening 21 in the end plate 19. A plurality of recesses 26, which are uniformly distributed in the circumferential direction, are introduced into the edge 25 of the skirt 24. The circumferential sections 27 present between the recesses 26 support the detent projections 23. The peripheral sections 27 are slightly elastically deflectable radially inwardly, as a result of which the fixing or removal of the end plate 19 is facilitated. On the outer sides 28 of the end plates 19, a toothed ring 29 protrudes in the direction of the longitudinal axis 16. This serves to crimp the implant to a vertebral body.

p0019Two perforations 30 are provided in the circumferential sections 7a. The openings 30 as well as the central opening 21 in the end plates 19 serve for filling bone material, bone cement or the like. A radially oriented threaded bore 33 is provided in one of the circumferential sections 7a near the nut 3. This serves to fix the handling tool described in the following.

p0020How <figref idrefs="f0006">FIG</figref> This is essentially constituted by a rod 34, one end of which carries a handle 35 and the other end of which carries a threaded portion 36. The region of the rod 34 extending away from the threaded portion 36 is coaxially enclosed by a rotary sleeve 37. The end of the rotary sleeve 37 facing the handle 35 carries a knurled wheel 38 and the opposite end has a toothed ring 39. This is similar to the nut 3, produced by a milling machining of the sleeve end face. An axial movement of the sleeve 37 in the direction of the handle 35 is limited by a stop flange 39.

p0021For adjusting the height of the implant, for example, from the position shown in FIG <figref idrefs="f0001">FIG</figref> The handling tool 'is screwed into the threaded bore 33 with its threaded portion 36. In this case, the toothed ring 39 is in engagement with the toothed ring 17 in the manner of a crown wheel gear, ie, the axis of the toothed ring 39 runs essentially at right angles to the axis of the toothed ring 17. The knurled wheel 38 rests against the stop flange 29.

p0022After the implant has been inserted into the spinal column via an operative opening, the rotary sleeve 37 is rotated by actuating the knurled wheel 38 to adjust a larger height of the implant. If the outer thread 4 of the sleeve part 2 and the inner thread 10 of the nut 3 are a right thread, the nut 3 must be rotated in the direction of the arrow 40 and the knurled wheel in the direction of the arrow 43. To loosen the handling tool from the implant, its threaded portion 36 is removed from the threaded bore 33 by rotating the handle 35. Since the sleeve 37 can rotate around the rod 34, it is not necessary to hold the rotary sleeve while the threaded portion 36 is being turned out. The fixing of the once adjusted relative position between the two sleeve parts 1, 2 can be accomplished in various ways. A simple possibility is to screw into the threaded bore 33 a screw (not shown) provided with a tip.

Reference list

p0023<dl id="dl0002" compact="compact"><dt>1</dt><dd>First sleeve part</dd><dt>2</dt><dd>Second sleeve part</dd><dt>3</dt><dd>mother</dd><dt>4</dt><dd>External thread</dd><dt>from</dt><dd>Front side</dd><dt>6</dt><dd>window</dd><dt>7a, b</dt><dd>Circumferential section (A = first sleeve portion; B = second sleeve part)</dd><dt>8th</dt><dd>Base</dd><dt>9</dt><dd>Axial distance</dd><dt>10</dt><dd>inner thread</dd><dt>13</dt><dd>Longitudinal section</dd><dt>14</dt><dd>Ring groove</dd><dt>15</dt><dd>head Start</dd><dt>16</dt><dd>Central longitudinal axis</dd><dt>17</dt><dd>Tooth ring</dd><dt>18</dt><dd>Front side</dd><dt>19</dt><dd>Front plate</dd><dt>20</dt><dd>Ring groove</dd><dt>21</dt><dd>opening</dd><dt>23</dt><dd>Resting</dd><dt>24</dt><dd>apron</dd><dt>25</dt><dd>edge</dd><dt>26</dt><dd>Recess</dd><dt>27</dt><dd>Circumferential section</dd><dt>28</dt><dd>Outside</dd><dt>29</dt><dd>Ring ring</dd><dt>30</dt><dd>Breakthrough</dd><dt>33</dt><dd>Tapped hole</dd><dt>34</dt><dd>Rod</dd><dt>35</dt><dd>Handle</dd><dt>36</dt><dd>Thread section</dd><dt>37</dt><dd>Rotary sleeve</dd><dt>38</dt><dd>Knurled wheel</dd><dt>39</dt><dd>Mounting flange</dd><dt>40</dt><dd>arrow</dd><dt>43</dt><dd>arrow</dd></dl>