DE102008010607B4 - Implant device for the spine - Google Patents

Abstract

Spine implant device for reconstructing spinal defects with an outer basket (40) and an inner basket (11) guided in the outer basket (40), wherein the implant device is adjustable in height, the outer basket (40) and the inner basket (11) have corresponding toothings (26, 26). 41) and the serrations (26, 41) on the inner (11) and outer basket (40) are self-retaining in at least one spatial direction, characterized in that the inner basket (11) merges into a second outer basket part (34) and is integrally connected thereto and the baskets (11, 40) and basket parts (34) are U-shaped and on the front side of the first outer basket (40) and the second outer basket part (34) vertebral support surfaces (14) and / or webs ( 15) are provided.

Description

The present invention relates to a height-adjustable implant device for the spinal column for the reconstruction of spinal defects. In particular, the device serves to replace parts of the vertebral bodies and adjacent discs.

The previously known corpectomy implants are based on the jack principle and thus allow height adjustment. A disadvantage of these implants, however, is that a bony Durchbauung the implants is hardly possible because they are designed sleeve-shaped and thus allow little to no contact with the healthy bone and also provide little biological stimulus to bone regeneration. Even after the healing of the wound in these cases, the entire burden on the implant, which can lead to fatigue fractures of the cover plates of the anchoring vertebra with sinking of the implant and painful misalignments to the risk of paraplegia by compression of the spinal cord.

Such sleeve-shaped, height-adjustable implants are made of DE 196 04 246 B4 and the DE 202 07 853 U1 known.

Another disadvantage of these implants is that the variability of the implant in height can be exclusively linear, d. H. the implant does not allow the option of following, for example, in the neck area the natural slight curvature - the lordosis.

A further disadvantage of the implants known hitherto is that they can not secure the spinal canal against a renewed constriction, for example due to unintentional displacement of bone chips past the implant or, alternatively, bone cement introduced as a result of the design.

A disadvantage of these implants according to the jack principle is that they sink in, especially if no additional bony stiffening arises.

From the US 5,562,074 B2 a rectangular height-adjustable implant device is known which consists of an outer and an inner basket and a reinforcing element. As a result of the reinforcing element, this device does not allow any bumping. Outer and inner basket are aligned in this device to each other so that in each case the bottoms of the U-shaped outer and inner baskets form the Wirbelstückflächen.

Furthermore, corpectomy implants are known which have the shape of a U-shaped cage. These implants can be filled with bone material, so that an ossification of the implant can be achieved. A height adjustment of these implants is not provided as such. The adaptation of the implants to the required height is carried out in these implants such that they are shortened during the operation to the desired length and the outer edges are slightly rounded in it. Disadvantage of these implants is that they sink into the vertebral body, which can lead to misalignments and renewed constrictions of nerve structures / spinal cord or impairments / failure of neighboring discs.

Another disadvantage of these implants is that often the length determination is difficult and the reduction does not take place to the appropriate length, so that the implant must be removed again and another implant must be implanted.

Furthermore, from the EP 1 267 755 B1 a height-adjustable vertebral implant is known, which consists of a first substantially U- or C-shaped basket and trained on the basket vertebral support surfaces. The first basket is an inner basket which is gripped and telescoped by a second outer U- or C-shaped basket. The legs of the inner and outer basket are aligned so that a continuous front opening results. On the front sides of the baskets vertebral support surfaces are provided. The inner basket further has in the region connecting the legs on a longitudinally extending slot with a one-sided toothing. The displacement of the two baskets against each other by means of an instrument with an external toothing. When the desired height is reached, the baskets are secured in the respective position by three screws.

The implant is height adjustable and can be filled with bone material through the continuous front opening and thus bony heal. Then the implant sinks only slightly into the vertebral body.

The disadvantage, however, that three screws in the direction of the spinal cord must be introduced aiming to fix the two baskets. The screwing in the direction of the dura can cause irritation of the spinal cord.

Due to the necessary wall reinforcements in the area of the fixation screws, the side facing the spinal cord / dura also has a protrusion which can either trigger a local dura-irritation or force positioning at a greater distance from the spinal cord than optimally.

Furthermore, it is disadvantageous in this implant that it is in the - most common - use of only one vertebral body z. B. in the neck area due to design has too little Aufspreizweg and therefore can not be anchored safely.

Also for use in the upper thoracic spine area, the mismatch between distensibility and required Aufspreizweg this implant often proves to be an exclusion criterion for use in transthoracic (ventral) technique.

For the operative option of introducing dorso-lateral (from the rear laterally past the spinal cord), there is, in addition to the low spreadability and the difficulty that the Aufspreizmechanismus "around the corner" at 90 degrees twisted implant can not be used.

The object of the present invention is to provide a height-adjustable fillable with bone or bone substitute implant, which is also used as a corpectomy basket, in which the spreading is not limited to the direction of insertion and in which the threat to the dura is avoided.

This object is achieved in that the outer basket and guided in the outer basket inner basket have corresponding teeth and the teeth on the inner and outer basket is self-holding in at least one spatial direction, the inner basket merges into a second outer basket part and is connected to this cohesively , Baskets and basket parts are U-shaped and provided on the front side of the first outer basket and the second outer basket part vertebral support surfaces and / or webs.

Due to the self-holding toothing in at least one spatial direction, the number of screws required for fixing can be reduced or even a fixation can be achieved without any screws, so that a threat to the dura is reduced or even avoided.

Preferably, inner and outer basket further means, which engage in each other and cause a fixation in the / the other spatial directions). These means may be, for example, projections and corresponding recesses or openings in which the projections can be guided. In principle, the projections can be arranged both on the inner basket, as well as on the outer basket.

The openings or recesses may be formed as slots or slot-shaped recesses. As a result, with appropriate shaping of the elongated holes or slot-shaped recesses, the guidance of the inner basket in the outer basket can be achieved in a small curvature line corresponding to the lordotic form.

Of course, further guide means can be provided on the inner and outer basket, which support a shift in the lordotic form.

The fixation of inner and outer basket is carried out according to the invention by locking the arranged on the two baskets teeth and not - as known from the prior art - by three both the inner and the outer basket in the ground traversing screws. As a result, a greater spreadability is achieved in the basket according to the invention.

Another significant advantage of the invention is that the implant in addition to a mechanical Aufspreizfunktion allows the shaping of new bone to be formed or, alternatively, in tumors for filling with bone substitute material.

A particular feature of this invention is that the implant can first be optimally placed and then the surfaces of the anchor vertebrae not required for support can be refreshed. This avoids the weakening of the implant bed by freshening the end plates prior to implantation, as required by the implants known from the prior art. Optimal refreshment of the adjacent vertebrae results in a rapid incorporation of the implant and reduction of complications (sinking, delayed or missing ingrowth).

A further advantage of the present invention is that the spreading mechanism can also be used "around the corner" in a 90-degree twisted implant, since the openings for the intervention of the instruments are arranged laterally and no fixation on the floor must take place with the implant according to the invention.

The invention will be described in more detail below with reference to exemplary embodiments.

It shows:

1 an exploded view of the inner basket, the outer basket and the blocking element according to a first preferred embodiment,

2 the implant out 1 with inner and outer basket pushed together,

3 a perspective view of the vertebral support surface of the implant 1 and 2

4 a second preferred embodiment of an implant with inner and outer basket in side view,

5 a perspective view of the embodiment according to 4 with screws from above and

6 a perspective view of the embodiment 4 with screws diagonally from below.

The implant comprises a first outer basket 40 as well as an inner basket 11 in a second outer basket part 34 passes over and is connected to this cohesively. All baskets and basket parts 11 . 40 and 34 are U-shaped. The inner basket 11 includes a floor 21 and two thighs 12 wherein each leg is a slot-shaped recess 22 and a tongue 24 having. The implant is mirror-symmetrical with respect to the plane in the direction of the longitudinal axis L.

At the front of the first outer basket 40 and the second outer basket part 34 that with the inner basket 11 is rigidly connected, are vertebral support surfaces 14 or footbridges 15 and alternately to these support surfaces 14 or webs 15 are in the longitudinal direction L extending serrated Arretierungsvorsprünge 17 intended. The vertebral support surfaces 14 or footbridges 15 are opposite the faces of the legs 36 . 43 the second outer basket part 34 and the outer basket 40 widened to provide a sufficiently large support for the vertebral bodies and to allow a firm anchoring of the implant to the end plate of the adjacent vertebra. According to the anatomical requirements of individual spinal column sections, the support surfaces can be made deviating from the right angle or can be equipped with bevelled end plates.

The locking projections 17 At the respective vertebral support surfaces can be cut at their tips 18 have for superficial penetration and for optimal anchoring to the respective opposite end plate of the adjacent vortex body.

The inner basket 11 points in the area of each leg 12 a longitudinal hole L extending slot-shaped recess 22 up on the in the direction of the leg ends 23 , ie in the LX direction, directed side by an elongated tongue 24 is limited. The slot-shaped recess 22 serves to guide the on the inside of the thigh 43 the outer basket 40 arranged guide webs 46 ,

The tongue 24 points to its end 25 on the outward-facing side a gearing 26 on, to the interlocking with the gearing 41 on the thigh inside 42 on the outer basket 40 serves.

The gears 26 . 41 are designed so that a self-holding function is achieved by their intervention.

Initially, the ends point 25 the tongues 24 with the teeth 26 however, slightly towards the symmetry plane E (in LX direction), leaving the inner basket 11 opposite the first outer basket 40 can be moved without the gearing 26 . 41 mesh. A spreading of the ends 25 the tongues 24 to the outside and thus an engagement of the teeth 26 in the complementary gearing 41 the outer basket 40 is only by spreading the ends 25 the tongue 24 on the thigh 12 by inserting a locking element 60 causes.

For this, every tongue points 24 on the inside of her end 25 a depression 20 for receiving the blocking element 60 on.

On the other side of the slot-shaped recess 22 have the thighs 12 of the inner basket 11 one section each 28 with round openings 27 . 27 . 30 on, which serve for the intervention of instruments and for the bony ingrowth. The opening 30 at the end of the section 28 has a projection on its outside 31 on, whose outer diameter 32 slightly smaller than the inner diameter in the X direction 47 the long hole 44 in the outer basket 40 is, so the lead 31 in the slot 44 can be performed. The leadership advantage 31 can also without appropriate opening 30 to be provided.

On the bottom side 21 has the inner basket 11 also openings 33 for optical control of the spinal canal or dura during and after implant placement. This increases the safety of the implantation and reduces the radiation exposure by reducing the number of required X-ray controls.

In the transition area of the outward-facing side of the floor 21 of the inner basket 11 and the outwardly facing sides of the leg portions 28 runs in the longitudinal direction of a groove 39 that is the leadership of a corresponding rail 48 in the inward facing corner area of the outer basket 40 serves.

The slot-shaped recess 22 and footbridge 46 as well as long hole 44 and annular projection 31 as well as groove 39 and rail 48 , which all run in the L direction in a slightly deviating form from a straight line, serve to make the inner basket 11 opposite the outer basket 40 in one of the lordotic form, e.g. B. the cervical spine corresponding small curvature line can be moved without tilting.

To the tongues 24 , the leg sections 28 and the bottom side 21 of the inner basket 11 closes on the tongue ends 25 opposite side over an outwardly extending step 35 the outer basket part 34 of the inner basket 12 on, in its embodiment the outer basket 40 with respect to its wall thickness, the rigid U-profile and the configuration of the end regions substantially corresponds. The outdoor basket part 34 serves the same purpose as the outer basket 40 except that at the outer basket part 34 Locking and guiding function are not required.

The outdoor basket part 34 points in his thighs 36 and his soil 37 also openings 38 which are used for the intervention of instruments, for visual inspection during implantation and possibly for bony healing.

The thigh 43 of the outer basket 40 each have a slot 44 on, in which the stiffening 31 in the leg section 28 of the inner basket 11 to be led. On the two inner sides 42 the thigh 43 of the outer basket 40 are gears 41 provided for engagement in the corresponding toothings 26 on the outside of the tongue 24 at the inner basket 11 serve.

On the insides 42 the thigh 43 of the outer basket 40 or the outer basket part 34 are near the vertebral support surfaces 14 Stege 51 intended. These bridges 51 serve as bearing surfaces to spread the implant by means of pliers. In these bridges 51 are preferably provided holes for screws, which serve to the implant on the web 51 to screw with the vertebral body and to avoid tilting of the implant.

in basket 11 and outside basket 40 form through the guidance of the inner basket 11 in the outer basket 40 and the leadership of the stiffening 31 in the closed slot 44 one unity. outside basket 40 and inner basket 11 and the outer basket unit rigidly connected thereto 34 of the inner basket 11 are over the open side 45 filled with bone chips or bone substitute material. A bony structure with the neighboring vertebrae is through the openings 16 in the vertebral support surfaces and the openings ( 27 . 30 ) possible.

Through the teeth with self-holding function and the leadership of the inner basket 11 in the outer basket 40 a secure locking of the implant in the desired height position is achieved without additional screwing. The toothing is self-holding, so that neither a screw to prevent the sliding apart nor a screw to prevent the sliding together nor a screw to prevent tilting is required.

By the leadership of the annular projection 31 in the closed slot 44 form inner basket 11 and outside basket 40 a captive entity.

In the 4 . 5 and 6 a further embodiment of an implant according to the invention is shown, which also has an inner basket 11 with an associated outer basket part 34 and an outside basket 40 includes, wherein the end faces of outer basket 40 and outdoor basket part 34 again essentially as in the previous embodiments are configured. These implants are engaged by a toothing in the + X direction 56 on the outside of the thigh 12 of the inner basket 11 into the gearing 55 on the outside of the thigh 43 of the outer basket 40 and the shape of the gearing, which is a displacement of the inner basket 11 in -L direction locks, a first fixation. Furthermore, cams 57 on the outside of the thigh 12 of the inner basket 11 arranged in a slot 44 in the outer basket 40 are guided. The sizing of the cam 57 in the X direction is chosen so that the height of the cam 57 in + X-direction plus the height of the toothing ( 55 . 56 ) in the + X direction is less than or equal to the height of the slot measured in the X direction 44 is.

On the bottom of the inner basket 11 is still a gearing 64 intended. The outer basket 40 has a tongue in extension of its bottom 58 with openings 59 on that in a recess 54 on the ground 61 the outer basket part 34 of the inner basket 11 intervenes. To unlock the implant by lifting the inner basket 11 To prevent the height of the teeth, must be the inner basket 11 opposite the outer basket 40 be fixed in the X direction. This can be done by a screw 70 through an opening 62 in the bottom of the inner basket 11 which is a slot, and an opening 63 in the bottom of the outer basket 40 respectively.

Claims (14)

Spinal implant device for reconstructing spinal defects with an outer cage ( 40 ) and one in the outer basket ( 40 ) guided inner basket ( 11 ), wherein the implant device is height-adjustable, the outer basket ( 40 ) and the inner basket ( 11 ) corresponding toothings ( 26 . 41 ) and the toothings ( 26 . 41 ) on the inner ( 11 ) and outer basket ( 40 ) are self-retaining in at least one spatial direction, characterized in that the inner basket ( 11 ) in a second outer basket part ( 34 ) passes over and is materially connected to it and the baskets ( 11 . 40 ) and basket parts ( 34 ) are U-shaped and on the front side of the first outer basket ( 40 ) and the second outer basket part ( 34 ) Vertebral support surfaces ( 14 ) and / or webs ( 15 ) are provided. Implant device according to one of the preceding claims, characterized in that the inner basket ( 11 ) a slot-shaped recess ( 22 ) for guiding the at the outer basket ( 40 ) arranged guide means ( 46 ) having. Implant device according to one of the preceding claims, characterized in that the inner basket ( 11 ) two legs ( 12 ) and the legs ( 12 ) of the inner basket ( 11 ) a gearing ( 26 ), which for toothing with a toothing ( 41 ) on the inside of the thigh ( 42 ) on the outer basket ( 40 ) serves. Implant device according to claim 3, characterized in that the engagement of the toothing ( 26 ) in the complementary gearing ( 41 ) of the outer basket ( 40 ) by spreading the ends ( 25 ) of the thighs ( 12 ) or a tongue ( 24 ) on the thighs ( 12 ) by inserting a blocking element ( 60 ) is effected. Implant device according to one of the preceding claims, characterized in that on the inner basket ( 11 ) Medium ( 31 ) are provided, which for guiding in a slot ( 44 ) in the outer basket ( 40 ) serve. Implant device according to one of the preceding claims, characterized in that the slot-shaped recess ( 22 ) and the guiding means ( 46 ) as well as the slot ( 44 ) and the guiding means ( 31 ) are positioned and configured so that the inner basket ( 11 ) opposite the outer basket ( 40 ) is displaceable without tilting in a small curvature line corresponding to the lordotic form. Implant device according to one of the preceding claims, characterized in that on the end face of the first outer basket ( 40 ) and the second outer basket part ( 34 ) longitudinally extending serrated locking projections (FIG. 17 ) are provided. Implant device according to claim 7, characterized in that the locking projections ( 17 ) at the respective vertebral support surfaces ( 14 ) at her tips a cut ( 18 ) exhibit. Implant device according to one of the preceding claims, characterized in that the vertebral support surfaces ( 14 ) or bridges ( 15 ) with respect to the end faces of the legs ( 36 . 43 ) of the second outer basket part ( 34 ) and the outer basket ( 40 ) are widened. Implant device according to one of the preceding claims, characterized in that inner ( 11 ) and outer basket ( 40 ) form a captive entity. Implant device according to one of the preceding claims, characterized in that openings ( 16 ) in the vertebral support surfaces and / or openings ( 27 . 30 ) in the thighs ( 12 . 43 ) and in the ground ( 21 . 49 ) of outdoor ( 40 ) and inner basket ( 11 ) are provided. Implant device according to one of the preceding claims, characterized in that the implant with respect to the plane in the direction of the longitudinal axis L is mirror-symmetrical. Implant device according to one of the preceding claims, characterized in that the device can be filled with bone or bone substitute material. Implant device according to claim 1 for the replacement of parts of the vertebral bodies and the adjacent intervertebral discs.

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