DE10309986B4 - Implant, implant system for rebuilding a vertebral body - Google Patents

Abstract

implant (30) to rebuild one of its carrying capacity or broken vertebral body (16) a human spine (10), characterized in that the Implant (30) of a variety of body-friendly, edge-free, individually in an interior space (17) of the vertebral body (16) insertable implant elements (28) exists.

Description

The The invention relates to an implant for the reconstruction of a in his activity restricted or broken vertebral body a human spine and an implant system comprising an implant and an insertion device for insertion of the implant in an interior of the vertebral body.

One vertebra the human spine can in its carrying capacity limited due to illness or due to an accident or illness. A disease-related injury of the vertebral body can be caused for example by osteoporosis.

The Osteoporosis is a disease of the total skeleton that is characterized by low bone mass and impairment of microarchitecture of the bone tissue and increased bone fragility leads. The treatment of osteoporotic vertebral body fractures proves to be extraordinarily difficult. A well-known therapeutic option is the percutaneous Vertebroplasty. In this procedure, the fractured vertebra with liquid Bone cement filled up and so in its stability strengthened. The operation is over a percutaneously introduced hollow cannula, which transpedicularly in the vertebra is placed. Either a sterile bone cement is used the relatively long remains fluid or injectable biodegradibles calcium phosphate. A prerequisite for such an operation is that the trailing edge of the vertebral body to be treated intact, so as to allow penetration of the bone cement into the spinal canal The spine to avoid.

Problematic in percutaneous vertebroplasty is that the bone cement in liquid form under Pressure must be injected. This carries the risk of embolism. To avoid this, the bone cement can also injected into a shell introduced into the vertebral body prior to injection from which he can not escape.

One Another method is described in WO 02/47563 A1, in which a filler in one in the vertebral body introduced expandable bag is filled.

It is therefore an object of the present invention, an implant and an implant system of the type described above to improve so that the surgical Intervention for inserting the implant can be performed easily and safely can.

These Task is in an implant of the type described above according to the invention thereby solved, that this Implant of a variety of body-friendly, edgeless, individually insertable into an interior of the vertebral body Implant elements consists.

The implant according to the invention has opposite Injecting liquid Bone cement in the vertebral body the advantage of that to no embolisms can come. Moreover, the procedure is simplified, because an implantation time is not limited by a curing time of the bone cement, because the implant elements of the present implant to be implanted are already in their final Shape in the vertebral body introduced. Farther can also be on an additional Cover for recording omitted the implant elements in the vertebral body become. This shortens on the one hand the operation time and on the other hand allows the use a particularly simple insertion instrument.

Preferably the implant elements are substantially inelastic. After this Introduce the implant elements in the vertebral body support each other from each other and thus hold the upright vertebral body in a desired, essentially its original natural Shape corresponding shape.

Especially The implant elements can be easily inserted if they are in the essentially have the shape of a sphere, since they are due to this Virtually can not tilt shape. In addition, an optimized through growth of the implant introduced with natural Bone substance possible, because even with a densest spherical packing still remain spaces.

A especially high stability is achieved when the implant elements have a diameter in the range from 3 to 8 mm. This also prevents implant elements emerge from the vertebral body, which is no longer completely closed due to a fracture can.

Cheap is it if the implant elements made from a hardened bone cement are. When using hardened Knochenze ment usually can not cause rejection reactions of the body come.

According to one preferred embodiment of Invention may be provided that the bone cement calcium phosphate Contains (CaP). this makes possible The use of already known and proven in practice bone cements.

The initially stated object is further described in an implant system of the beginning NEN type solved according to the invention in that the implant is one of the implants described above, that the insertion device comprises an insertable into the vertebral body introducer sheath and that the introducer sheath has an inner cross-section which corresponds substantially to the outer dimensions of an implant element.

With Such an implant system can be easily Implant elements individually, that is, in particular successively, in the vertebral body introduce. This can be the vertebral body filled with the implant.

Especially surely the implant elements can be injected into the vertebral body, if the introducer a circular Internal cross-section and when the inner cross-section maximum 10% larger as an outer diameter a single implant element. An insertion sleeve with such an inner cross section allows it, without blocking the implant elements in the introducer sheath, this individually and one after the other into the vertebral body.

In principle, it would be conceivable the implant in the longitudinal direction from the insertion sleeve to lead this out. Cheap However, it is when the introducer sheath on a distal end has at least one pointing in the radial direction outlet opening. One Lateral leakage of the implant from the introducer sheath has the advantage that the implant is optimally distributed in the interior of the vertebral body. Further let yourself prevent that Implant from the vertebral body forced out becomes. It would be possible for example, even two radially outwardly facing, diametrically opposite Provide slots on the insertion sleeve.

Advantageous It may be when the implant passes through a pedicle canal can be used. By a pedicle can be easily form an access to the interior of the vertebral body.

Cheap is it, if access to the interior of the vertebral body after insertion of the Lockable implant is. In this way it is avoided that the implant through the access can emerge again when, for example, forces on the vertebral body and so that they are applied to the introduced implant.

On Particularly simple way, a leakage of the implant from the vertebra be prevented when a plug or bone cement for closing the Access to the interior of the vertebral body after insertion of the Implant is provided.

Cheap is it, if the implant is radially pushed out of an insertion sleeve. On this way it can be distributed particularly well and evenly in the interior of the vertebral body become. Furthermore, a risk is minimized that the implant directly after the insertion is pushed out of the vertebral body again, for example, due to a fracture open spot or through a weakened Wall of the vertebral body.

In addition, will below describes a method in which an insertion instrument in the form of an introducer sheath into one Interior of the vertebral body introduced and by placing an implant of the type described above in the unprepared vertebra is injected by successively placing implant elements in the vertebral body be inserted.

This Procedure allows the reconstruction of a damaged, For example, osteoporotic vertebral body in the simplest way. The vertebral body must ago the preparation of the implant are not prepared, that is, the Implant elements are inserted directly into the vertebral body. This also means that straight no additional container initially in the vertebral body be introduced must, in which in known methods, the implant is introduced. It can be shortened in this way operation times. Further In the case of the method according to the invention, the implant adapts optimally Way to the vertebral body to be rebuilt.

Around It may be advantageous to simplify the insertion of the implant be when the spine before and during the insertion of the implant is stretched. That way only relatively low feed forces needed for introducing the implant elements into the vertebral body.

The following description of a preferred embodiment of the implant and of the implant system for the reconstruction of an osteoporotic vertebral body in conjunction with the drawings for further explanation. Show it:

1 : a schematic representation of the introduction of an implant according to the invention with an insertion instrument into a fractured vertebral body of a spinal column;

2 : A schematic representation of a rebuilt with an inventive implant fractured vertebral body.

In 1 is a section of a spine 10 of a human body. Zwi two discs 12 and 14 is a vertebral body 16 a vortex 18 on a ventral side 20 collapsed due to an osteoporotic change and partially broken.

To rebuild the vertebral body 16 gets through a pedicle 22 of the vortex 18 a cannula 24 transpedicular, ie by one in the pedicle 22 opened access, introduced until a front end 26 the cannula 24 in an interior 17 in the vertebral body 15 has penetrated. The spine 10 may, but need not, during the introduction of one of a variety of calcium phosphate beads 28 existing implant 30 through the cannula 24 be stretched through, so that the to be treated vertebral body 16 adjacent intervertebral discs 12 and 14 already during implantation of the implant 30 assume their original, substantially parallel position.

The injection or insertion of the implant consists of the beads 28 in the direction of arrow A through the cannula 24 push it through until it's out of a side opening 34 in the area of the front end 26 the cannula 24 escape. The leakage is facilitated by a to the opening 34 inclined or curved deflection surface 36 , The beads 28 then fill cavities of the vertebral body 16 out. In particular, brittle bone tissue gets through the beads 28 displaced and compacted. By turning the cannula 24 can the beads 28 in different directions in the interior 17 be introduced. An optimized filling of the interior 17 of the vertebral body 16 is achieved when the cannula 24 during the injection of the beads 28 turned and slowly withdrawn. In this way, the beads can 28 the interior 17 of the vertebral body 16 fill in compact, as in 2 is shown.

Upon completion of the implantation, the implant fills 30 a part of the vertebral body 16 and keeps it essentially in its original form.

The cannula 24 becomes out of the vertebra after successful implantation 18 removed and the vertebral body 16 if necessary by means of a seam or otherwise closed. It is also conceivable, the pedicle 22 opened access with a stopper made of a biocompatible material or to close with bone cement.

Claims (13)

Implant ( 30 ) for rebuilding a vertebral body restricted or fractured in its carrying capacity ( 16 ) of a human spine ( 10 ), characterized in that the implant ( 30 ) of a variety of body-friendly, edge-free, individually in an interior ( 17 ) of the vertebral body ( 16 ) insertable implant elements ( 28 ) consists. Implant according to claim 1, characterized in that the implant elements ( 28 ) are substantially inelastic. Implant according to one of the preceding claims, characterized in that the implant elements ( 28 ) have substantially the shape of a sphere. Implant according to one of the preceding claims, characterized in that the implant elements ( 28 ) have a diameter in the range of 3 to 8 mm. Implant according to one of the preceding claims, characterized in that the implant elements ( 28 ) are made of a cured bone cement. Implant according to claim 5, characterized in that that the Bone cement contains calcium phosphate (CaP). Implant according to one of the preceding claims, characterized characterized in that Implant can be inserted through a pedicle channel. Implant according to one of the preceding claims, characterized characterized in that a Access to the interior of the vertebral body is closable after insertion of the implant. Implant according to claim 8, characterized in that the existence Plug or bone cement for closing access to the interior of the vertebral body is provided after insertion of the implant. Implant according to one of the preceding claims, characterized characterized in that Implant can be pushed radially out of an insertion sleeve. Implant system comprising an implant ( 30 ) and an insertion device for inserting the implant ( 30 ) in an interior ( 17 ) of a vertebral body ( 16 ), characterized in that the implant ( 30 ) an implant ( 30 ) according to one of the preceding claims, that the insertion device into the vertebral body ( 16 ) insertable introducer sheath ( 24 ) and that the introducer sheath ( 24 ) an inner cross-section ( 32 ) substantially corresponding to the external dimensions of an implant element ( 28 ) corresponds. Implant system according to claim 11, characterized in that the insertion sleeve ( 24 ) has a circular inner cross-section ( 32 ) and that the inner cross-section ( 32 ) is at most 10% larger than an outer diameter of a single implant element ( 28 ). Implant system according to one of claims 12 or 13, characterized in that the insertion sleeve ( 24 ) at a distal end ( 26 ) at least one radially outwardly pointing outlet opening ( 34 ) having.