DE102012203256A1 - Implant structure for supporting spine in inter vertebral space, has anterior support element and posterior support element that are connected with adjusting mechanism where support elements are spaced apart at a distance - Google Patents

Abstract

The implant structure (1) has an anterior support element (40) and a posterior support element (70) that are connected with an adjusting mechanism (60). The anterior support element is spaced apart from a posterior support element at a distance (L). The height (h) of the anterior support element is adjustable. The angular position adjustable arm (41,42) of the anterior support element is connected with the joint portion (30) which is connected with the adjusting mechanism.

Description

The invention relates to a medical implant which can be inserted into the space between two vertebrae in order to stabilize the spinal column. The implant according to the invention is essentially characterized in that it consists of at least one support element with an adjustment mechanism, whereby further advantageous properties with regard to production, implantation and function in the body can be realized.

State of the art

In diseases of the spine, it is often necessary to stabilize one or more segments. There are a variety of intervertebral implants (also called "cages") that have a bony fusion of a spinal column section to the goal. The implantation of such cages can lead to numerous complications. For example, the implants can break into the cover plate due to a punctiform load or small contact surface, the desired, bony fusion can be omitted by "stress shielding", the implants can slip or the position of the vertebral bodies to each other can not be corrected sufficiently. In particular, the correction of the lordosis for setting a physiological Sagittalprofils is often insufficient. In addition, a secondary support (eg via a pedicle screw rod system) is generally required in order to stabilize the segment to the extent that migration of these implants is reliably prevented.

Out ( WO 9501763 A1 , 1993) a spinal implant is known, which consists of a basket-like ring and has a central opening for receiving bone material. In ( EP 1800627 A2 , 2005) has been described that a spinal implant for contact area enlargement of two or more rings may exist so as to reduce a break in the vertebral end plates. Out ( WO 0234171 A2 , 2000) are known deformable polymer strips, which are introduced into the vertebral body space and can be aligned to the load direction.

From the applications ( WO 2008079953 A2 , 2006), an arrangement of two or three rigidly connected plates is proposed in each case, which allow a space for the introduction of bone, bone substitute material or BMP by the distance of the plates. Here, the plates fulfill the function of a receptacle to introduce the mechanically unstable bone material in the intervertebral space and to prevent unwanted distribution in the disc space or in the body. Due to the desired function and the small number of plates no practical arrangements are provided which determines the distances of the interstices of a larger number of plates. Another disadvantage is the required extraction of bone to fill the gap, or the provision and introduction of other bone replacement materials.

The aforementioned inventions consist of or allow the introduction of bone or bone substitute material in the intervertebral space, but do not allow the correction of the vertebral position (angle and offset) nor provide solutions for uniform distribution of stress on the cover plates of the vertebral bodies. Due to the non-adjustable height of the implants, partially high impact forces and overdistraction of the end plates are required during implantation.

Out ( WO 0044319 A1 , 1999) discloses an expandable spinal implant. Through a small access to the intervertebral disk numerous folded elements can be inserted and placed by compression so that they distract the vertebrae. Out ( DE 19816832 C1 , 1998) and from ( US 2010010633 A1 , 2008) spinal implants are known which have at least one shaft with eccentrically attached discs. The shaft is rotatable so that the discs are exposed and the implant gains height. A potential disadvantage of this design is the need for a rigid connection between the shaft and the discs. Furthermore, these spinal implants are limited to the distraction, wherein a displacement of the vertebrae due to the rotatable shaft and the resulting friction between the discs and the cover plates can not be completely excluded. Clinical experience shows that, due to the largely cylindrical cross-section, a large number of these implants break into the cover plate and in some cases are difficult to revise.

In addition to the various shortcomings described above, all implants heretofore known include no or only simple toothing on the bone contact surfaces to increase resistance to migration. The mechanical generation of defined tooth geometries with an undercut is not known due to the previously used construction methods and manufacturing methods. When using bone as an implant material, the low strength of the material prohibits the design and application of such tooth geometries. task

task

The object of the present invention is to provide an implant for Stabilization of the spine over the intervertebral space. The most important task of the implant according to the invention is the distribution of the load on the epiphyseal ring of the vertebral body and the adjustability of the implant with respect to its length and / or height for optimum adaptation to the anatomically individual dimensions of the patient. Other optional features allow additional bone growth stimulus through micromotion of the implant framework, adaptation of the implant site angle, and correction of translational displacements. The implant according to the invention should also be inexpensive to manufacture and simplify the intra-operative handling.

solution

The problem is solved by the spinal implant consisting of two support elements; an anterior and a posterior support element. Connected both support elements via an adjusting mechanism, which can adjust the distance between the two support elements to each other. In a preferred variant, the height of at least one of the support elements is further adjustable. To increase the primary stability and to reduce the migration risk of the implant angle-adjustable wings, which can get caught with the vertebrae proposed. In addition, the implant can be axially biased via the adjustment mechanism, which can be used to reduce a vertebral misalignment and contribute to further increasing the stability.

advantages

An advantage of the implant according to the invention is the very high resistance against migration and breaking into the base and cover plates which is possible due to the special design of the support elements. Due to the adjustability of the implant length, the support surface can be adjusted precisely to the anatomical conditions of the patient without having to provide a large variety of implant sizes for this purpose. The height adjustment via a toggle mechanism allows the generation of high Aufrichtkräfte at moderate operating forces and large possible Aufrichtwinkel. By appropriate gearing or adjustment of the implant stiffness also a large stimulus for the formation of bone can be generated without the implant must be filled with additional bone or bone substitute material. The proposed wings for additional anchoring produce a high primary stability, so that in many cases can be dispensed with a secondary, posterior support.

Preferred details and embodiments

The technical solutions are often described below by way of example. This should be understood as a means of explaining the underlying idea and should not be construed as limited to the particular concrete representation. The embodiments described in detail herein form a combinatorial basis of the invention, that is, the embodiments may be performed individually or in combination with each other.

The implant according to the invention ( 1 ) is introduced into the interspace (B) of two vertebrae (W1, W2) in order to stabilize and support the spine ( 3 ). The spinal implant ( 1 ) consists of a supporting element ( 40 ) in the anterior region (A), a supporting element ( 70 ) for the posterior region (P) and an adjustment mechanism ( 60 ) for connecting both support elements ( 40 . 70 ) 1 , The adjustment mechanism allows the adjustment of the distance (L) of both support elements ( 40 . 70 ) to each other. Furthermore, the anterior support element ( 40 ) are adjusted in height (h). The height adjustment of the anterior support element ( 40 ) is achieved via the toggle lever principle. For this purpose, the anterior support element ( 40 ) of at least two adjustable legs ( 41 . 42 ). Connected are the thighs ( 41 . 42 ) via a central joint ( 30 ), which a connection to the adjustment mechanism ( 60 ) owns.

To optimize the shear stress of the central joint ( 30 ), the thighs ( 41 . 42 ) be multi-layered and with a different arrangement ( 2 ). The thigh ( 41 . 42 ) have openings ( 413 . 423 ) for attachment to the central joint ( 30 ). The thigh ( 41 . 42 ) can be made, for example, by injection molding of metal (Metal Injection Molding), plastic or other biocompatible or bioabsorbable materials, or a combination of these materials. Other particularly suitable manufacturing methods for the production of the legs ( 41 . 42 ) are the cutting out with the help of high-energy radiation (electron beam, LASER, water jet) or the etching out by a photochemical etching of metal strips, sheets or plates (photo-etching). The mentioned production methods offer a multiplicity of design possibilities of the legs ( 41 . 42 ) and allow the cost-effective integration of functions in the implant, which can not be realized by the known one or two-part, substantially monolithic embodiments. So it is for example possible in a simple manner, structures, profiles, guides, openings or gears with different depth of excavation in the leg ( 41 . 42 ), teeth with undercut produce or offset each teeth to the next leg ( 41 . 42 ).

The legs are guided ( 41 . 42 ) of the implant ( 1 ) over in the counter bearing ( 20 ) bearing surfaces ( 24 ) and / or axes ( 44 ). For the leg guidance with the help of additional axes ( 44 ) are the legs ( 41 . 42 ) with openings ( 412 . 422 ) Mistake. The adjustment of the distance (L) between the anterior ( 40 ) and the posterior ( 70 ) Support element is, for example, by means of a threaded sleeve ( 61 ), which via the adjusting mechanism ( 60 ) to be led. The threaded sleeve ( 61 ) has an internal surface with a thread ( 66 ) and may have a conical outer surface ( 612 ) and with slots ( 611 ) exhibit. This arrangement has the advantage that due to the slots ( 611 ) the threaded sleeve ( 61 ) has a reduced stiffness in the radial direction and so, without screwing, can be pushed over a thread. Once the conical outer surface ( 612 ) into a congruent surface of the joint ( 30 ), the radial rigidity and the toothing of the threaded sleeve ( 61 ) with the adjustment mechanism ( 60 ) restored. To increase the stabilizing effect of the spinal implant ( 1 ) is located distally of the legs ( 41 . 42 ) at least one wing ( 11 . 12 ), which via a joint ( 29 ) is adjustable in angle. An optional spring-elastic element ( 28 ) supports the erection of the wings ( 11 . 12 ) in a preferred orientation. For locking the wings ( 11 . 12 ) in the erected position, these can be spread over surfaces ( 15 ) on other means, for. B. a clamping element ( 50 ) issue. Furthermore, the wing or wings ( 11 . 12 ) with teeth ( 100 ), which are capable of penetrating into vortices (W1, W2). The implant according to the invention ( 1 ) is axially via the adjusting mechanism ( 60 ) braced. The distal wings ( 11 . 12 ) are in the direction of the posterior support ( 70 ) with the aid of a fixing element ( 76 ) pulled and secured. The posterior protection element ( 70 ) corresponds in this arrangement to a proximal wing. A non-slip connection on the posterior support element ( 70 ) with the help of teeth ( 700 ) and / or openings ( 72 ), wherein the openings ( 72 ) are provided for mounting additional bone anchors. The implant according to the invention ( 1 ) may be used in pairs via the dorsal approach in the treatment of spinal instability ( 3 ).

When placing the implant ( 1 ) in the intervertebral space (B), are the distal wing ( 11 . 12 ) and the thighs ( 41 . 42 ) in a folded position ( 4 ). Once the implant ( 1 ) is located in the intervertebral space (B), the distal wings ( 11 . 12 ) and the thighs ( 41 . 42 ) erected. Finally, the posterior support element ( 70 ) and with the fixing element ( 76 ) secured.

An alternative embodiment ( 2 ) creates the anterior support with the help of one or more wings ( 11 . 12 ). The wings ( 11 . 12 ) are over a joint ( 29 ) and connected via an abutment ( 20 ) or clamping element ( 50 ) adjustable in angle and lockable ( 5 ). To reduce the shear stress of the joint ( 29 ) own the wings ( 11 . 12 ) mutual recesses ( 111 ). The adjustment takes place via an adjusting mechanism ( 60 ), which the wings ( 11 . 12 ) with the posterior support element ( 70 ) connects. The wings ( 11 . 12 ) have a curvature that at the outer end in one or more teeth ( 101 ) opens. At the transition to the teeth ( 101 ) there is a shoulder surface ( 102 ), which serves as anterior support of the vertebrae (W1, W2). Furthermore, the teeth ( 101 ) an area ( 103 ) on the concave tooth side, which after the erection of the wings ( 11 . 12 ) are oriented as far as possible parallel to the vertebral body cover plates ( 6 ). Also this embodiment ( 2 ) can be implanted in pairs in the spine ( 7 ).

In an alternative embodiment ( 3a ) have the thighs ( 41 . 42 ) no direct contact with the bone tissue ( 8th ). The thigh ( 41 . 42 ) are between bearing surfaces ( 91 ) of the supporting element ( 90 ) clamped. Thus, the selective support of the legs ( 41 . 42 ) on a larger contact surface ( 91 ) transferred to the bone. The thigh ( 41 . 42 ) are adjustable in angle and with a central bearing ( 30 ) connected. Via an adjustment mechanism ( 60 ) the thighs ( 41 . 42 ) against an abutment ( 20 ), which movement in the direction of the bearing surfaces ( 91 ) ( 9 ).

In another version ( 3b ) have the bearing surfaces ( 91 ) at least one recess ( 94 ) into which the thighs ( 41 . 42 ) can engage or engage ( 9 ) and thus form the outer hinge points of the toggle lever. Instead of a recess, alternative connection options, such as a hinge joint, are also considered suitable. The bearing surfaces ( 91 ) of the supporting element ( 90 ) are preferably also curved according to the shape of the base and cover plate curvature performed to ensure a uniform load distribution on the vertebral body and in particular the epiphyseal ring. A hinge or a largely elastic connection of the bearing surfaces ( 91 ) with the supporting element ( 90 ) allows the change in angle of the bearing surfaces on the leg adjustable in its angular position ( 41 . 42 ).

figure description

1 shows the basic structure of the spinal implant according to the invention

2 describes the detailed structure of the implant.

3 represents the application of the implant in the intervertebral space.

4 illustrates the positions of the implant components during insertion and erection.

5 shows an alternative embodiment.

6 explains the positions of the implant components during implantation and after erection.

7 describes the application in the intervertebral space.

8th illustrates an alternative embodiment of the invention.

9 shows the height adjustment with the help of angle-adjustable legs.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 9501763 A1 [0003]
• EP 1800627 A2 [0003]
• WO 0234171 A2 [0003]
• WO 2008079953 A2 [0004]
• WO 0044319 A1 [0006]
• DE 19816832 C1 [0006]
• US 2010010633 A1 [0006]

Claims (15)

Implant ( 1 . 2 ) for supporting the spinal column (W1, W2) in the intervertebral space, comprising an anterior support element ( 40 ) and a posterior support element ( 70 ), characterized in that the two support elements with an adjusting mechanism ( 60 ), which is suitable for the two support elements ( 40 . 60 ) Set their distance (L) to each other. Implant according to claim 1, characterized in that the anterior support element ( 40 ) in its height (h) is adjustable. Implant ( 1 . 2 . 3a . 3b ) for supporting the spine (W1, W2) in the intervertebral space consisting of at least one support element ( 40 . 70 . 90 ), at least one abutment ( 20 . 24 . 44 . 94 ) and an adjusting mechanism ( 60 ), characterized in that at least one of the support elements ( 40 . 70 . 90 ) via adjustable in the angular position leg ( 41 . 42 ) in height (h) is adjustable and the arrangement of legs ( 40 . 70 ), Adjusting mechanism ( 60 ) and counter bearing ( 20 . 24 . 44 . 94 ) is designed as a toggle mechanism. Implant according to one of the preceding claims, characterized in that the adjusting mechanism ( 60 ) with in a central joint ( 30 ), which at the same time the legs ( 41 . 42 ) connects. Implant according to one of the preceding claims, characterized in that the legs ( 41 . 42 ) are multi-layered and arranged alternately. Implant according to one of the preceding claims, characterized in that the legs ( 41 . 42 ) in the area around the central joint ( 30 ) mutual recesses ( 111 ) exhibit. Implant according to one of the preceding claims, characterized in that the abutment ( 20 ) of the thighs ( 41 . 42 ) over surfaces ( 24 ) or axes ( 44 ), which is used to support the joints ( 41 . 42 ) are suitable. Implant according to one of the preceding claims, characterized in that distal to the legs ( 41 . 42 ) at least one wing ( 11 . 12 ) is arranged and the wing over a joint ( 29 ) are adjustably mounted in its angular position. Implant according to claim 8, characterized in that the wing ( 11 . 12 ) over at least one contact surface ( 15 ), which are adapted to lock the angular position of the wing. Implant according to claim 8 or 9, characterized in that the wing ( 11 . 12 ) over teeth ( 100 . 101 ) suitable for penetrating a vertebral body (W1, W2). Implant ( 3a . 3b ) according to any one of claims 3-10, characterized in that the legs ( 41 . 42 ) and the adjusting mechanism ( 60 ) within a distensible in the distal region support member ( 90 ) are stored. Implant according to claim 11, characterized in that the bearing surfaces ( 91 ) of the supporting element ( 90 ) about recesses ( 94 ) or hinged connections, which serve as an abutment of the legs ( 41 . 42 ) are suitable. Implant ( 2 ) for supporting the spine (W1, W2) in the intervertebral space, characterized in that it consists of rotatably mounted, erectile wings ( 11 . 12 ) consists of a suitable for erection tensioning element ( 50 ), the tensioning element ( 50 ) further comprising an adjusting mechanism ( 60 ), and the adjusting mechanism ( 60 ) with a posterior support element ( 70 ) connected is. Implant according to claim 13, characterized in that the wing or wings ( 11 . 12 ) over teeth ( 101 ), which are suitable for penetrating into the base or cover plate of the vertebral bodies. Implant according to claim 13 or 14, characterized in that the wings ( 11 . 12 ) over bearing surfaces ( 102 ) which are suitable for supporting against the base or cover plates of a vertebral body.

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