DE102009055826A1 - Device for plate osteosynthesis, has plate system with multiple application specific, stacked, lockable, uniform or curved individual plates of different forms and sizes - Google Patents

Abstract

The device has a plate system with multiple application specific, stacked, lockable, uniform or curved individual plates of different forms and sizes. Multiple mounting elements are provided for each individual plate. The individual plates form locking elements with through-holes (4) that are arranged in a catch as a detachable dowel joint, in which the dowels, such as straddling dowels are engaged for locking the individual plates. The former dowel is made of plastic material such as polyether ketone or polyethylene, and the latter dowel is made of metal such as titanium or surgical steel.

Description

The invention relates to a device for the surgical treatment of bone injuries, especially fractures. To fix the position of the bone or bone fragments serve plates made of metal, such as. As surgical steel and titanium, or even of plastics, such as fiber composites, by means of suitable fasteners, such as. As screws or pins, are internally connected to the bone on the principle of the fixator.

Known devices for plate osteosynthesis usually consist of a fracture zone bridging plate, which is usually fastened with screws on the bone (eg. US 3,695,259A ).

Problems still exist with the rigidity and strength of these devices, since these conditions have a decisive influence on bone healing. If the stiffness in the fracture area is too large or too small, this causes a delay or, in extreme cases, the absence of fracture healing. Clinically, such osteosynthesis often ends with a secondary fracture or implant failure. Additional problems cause too high plate stiffness in the area of healthy bone. Too high a plate stiffness causes a so-called "stress shielding". By this is meant the shielding of the healthy bone from the physiological burden which is essential for the maintenance of the substance of the bone. As a result, overload breaks occur at the ends of the plate osteosynthesis or secondary fractures after removal of the implant.

The stiffness of a plate osteosynthesis should ideally increase from the plate ends to the fracture zone and thereby gradually redirect the flow of force from the bone into the implant. Such implant devices are z. In WO 2008 / 077482A1 . US 6,001,099A . US 4,683,878A and US 4,955,886A described. The site-specific different stiffness is generated here by targeted material hardening or cross-sectional change over the course of the implant longitudinal axis. The disadvantage of all these approaches is the special predefined stiffness course due to the implant, so that the implant can only ideally supply only one particular fracture type. For a universal fracture supply, therefore, it would always be necessary to maintain a comprehensive supply of different implants that takes into account any surgical requirements, which would require an immense production and deployment effort and would thus be highly uneconomical.

It is also known to assemble the plate for osteosynthesis from loosely stacked sheet-like elements, which acquire a certain positional stability only by the anchoring of the implant to the bone (for example EP 449867 A1 and DE 10 2006 018 867 B3 ). Clinically, the use of such implants is very complicated and unreliable, since the surgeon in addition to the bone fragments also need to control the positioning of the many individual plates, resulting in a high process cost in use.

The invention is therefore based on the object to provide a device for plate osteosynthesis whose supply functions for the bone injury as possible aufwandgering and use-specific can be adapted to the respective surgical requirements.

Said surgical requirements are determined, for example, by fracture type, location, position and specific patient characteristics such as size, weight, bone quality and already set implants.

According to the invention, a plate system for osteosynthesis is proposed, which consists of several use-specific one above the other lockable individual plates of different shape and size, being provided on each and / or for each individual plate each arranged in an identical grid force and / or positive-locking fasteners.

For example, these fasteners may include detent clip connections, with special elements for clip training, such as annular beads or slotted rings, engage in receiving holes or clip elements of the adjacent single plate and connect the individual plates in this way non-positively and / or positively. Such compounds are (even during surgery or before) procedurally easily applicable and can be solved completely reversible again by moderate effort or appropriate tools.

Other connection options are, for example, other locking elements, dowel elements or screw with screws and grub screws.

With the plate system according to the invention, it is possible to select the implant in a very simple manner and easy to handle even immediately before or when used in accordance with the surgical requirements of plate osteosynthesis (in particular the type, location and location of the bone injury and patient specifics) or in the manner of one modular modular system to assemble and, if necessary, still on the operating table to assemble, if necessary, to change or disassemble again. The plate system itself consists of a supply of flat or curved individual plates of different shape and size, the individual plates each alone have no sufficient strength for adequate fracture supply, but are sufficiently thick for a position-fixed connection with each other or the fixed position receiving fasteners. Through the connection of the individual plates, the proposed device for plate osteosynthesis (in particular in size and location-dependent stiffness) can be adapted application-specific to the required supply conditions of the bone injury and possibly changed. The individual plates are made of biocompatible material, such as surgical steel, titanium, plastic, all individual plates can each consist of the same or different materials.

The finished implant is as uncomplicated as a conventional plate implant, consisting of a single plate to implant, since it is introduced as a force and / or form-fitting assembled (prefabricated) implant system in the body. It is advantageous if, when anchoring the implant on the bone or on the bone fragments, the fastening means (bone screws) penetrate the connecting elements between the individual plates and thus reinforce the connection of the individual plates. This is made possible, for example, by the said annular clip elements (beads or slotted rings) and receiving holes, through which the bone screws can each be guided centrally.

It would also be possible to produce the connection of the individual plates for operative use one after the other or to partially detach them during the implant removal. By removing or omitting connections between the individual plates, it is possible to partially decouple them mechanically so that no force is transmitted from the fastener to the corresponding single plate via the decoupled connections. This measure makes it possible to selectively reduce the axial stiffness and torsional stiffness of the implant-bone interface concerned without changing the flexural rigidity of the osteosynthesis.

By using a uniform grid of fasteners as many individual plates of different shape and size (length, width, thickness) can be combined with each other The arrangement of the resulting implant does not necessarily have to be symmetrical. Rather, the location-specific stiffness curve over the implant longitudinal axis can be adapted to the respective requirements such that, for example, the rigidity increases less from one end of the implant than the other end or the implant stiffness continues to increase from one end to the other. Should it be clinically necessary, an osteosynthesis with several stiffness maxima along the bone longitudinal axis can be realized by the invention.

The adjustable, graded stiffness curve makes it possible to divert the flow of force from the bone to the implant less abruptly and thus to protect surrounding healthy bones. This will be especially in difficult bony conditions such. B. periprosthetic fractures prove to be advantageous because in this case the stiffening of the bone fragments by existing implants (eg shanks of hip and / or knee endoprostheses) can be accommodated by appropriate design of the implant.

From the subclaims and embodiments, special design options of individual plates and fasteners can be seen. The scope of the invention is not limited to these.

The invention will be explained below with reference to exemplary embodiments illustrated in the drawing.

Show it:

1 Schematic representation of an implant system consisting of three individual plates

2 : Plate implant according to 1 with symmetrical stiffness course

3 : Plate implant with four single plates and asymmetrical stiffness curve

4 : Detail scheme for connecting the individual plates with clip elements

5 - 9 : Exemplary embodiment of clip elements for connecting the individual plates

10 : Schematic representation of the connection of the individual plates by threaded elements

11 : Schematic representation of the connection of the individual plates by expansion dowels

12 - 13 : Exemplary embodiments for expansion dowels for connecting the individual plates

1 to 3 show the basic schematic structure of a plate implant 1 respectively. 1a from individual plate elements 2 . 2a . 2 B different length, the plate elements 2 . 2a . 2 B . 3 are each assembled in a different local arrangement. In 1 are the plate elements 1 . 2 . 2a and 3 shown isolated. panel member 2 has (comparable to struts of a stable construction kit) five along its length arranged in series and distributed in the same grid through holes 4 on. In the same way has the longer plate element 2a nine through holes 4 in the same grid as the plate element 2 , At every through hole 4 is respectively at the bottom of the plate element 2 . 2a . 2 B a clip element 5 formed, which when stacking the plate elements 2 . 2a . 2 B . 3 respectively from above into the through hole corresponding to the grid 4 of the underlying plate member 2 . 2a . 2 B . 3 plug-in engagement for Lagearretierung. The minimum horizontal offset between the plate elements 2 . 2a . 2 B . 3 is doing through the pitch pattern pitch of the through holes 4 certainly. The clip elements 5 are each either directly from the plate element 2 . 2a . 2 B , worked out or made separately and then into the plate element 2 . 2a . 2 B , inserted.

In contrast to the plate elements 2 . 2a . 2 B has the lowest plate element 3 no through holes 4 , but arranged in the same grid threaded holes 6 in whose threads 7 for example, a screw 8th (see. 4 ) or engage an unillustrated threaded pin and thus the superimposed and by the clip elements 5 position-fixed plate elements 2 . 2a . 2 B . 3 positively and positively connect with each other and can attach. The lowest plate element 3 as with the fracture bone, not shown, entering Implantatplatt with the threaded holes 6 has no clip elements on its underside 5 on, so that the implant rests as flat as possible on said bone. However, it would be possible to provide this plate also with the same or similar clip elements, which serve in this case at the same time as a spacer between the implant and bone.

2 shows the three composite plate elements 2 . 2a . 3 from the exploded view of 1 without fasteners, so that the congruent grid of the through holes 4 and tapped holes 6 is apparent. The plate elements 2 . 2a . 3 are here for a symmetrical rigidity course of the plate implant 1 Centric (centered) arranged to each other.

In the same way shows 3 as a plate implant 1a an arrangement of a total of four plate elements 2 . 2a . 2 B . 3 each different length in a non-centric arrangement to each other (asymmetric stiffness gradient of the plate implant 1a ). Again, due to the grid, the corresponding through holes 4 and tapped holes 6 each arranged congruent.

The clip elements 5 are characterized by the fact that they have a preferably slotted bead 8th (see also 5 ), which is preferably designed so that they under moderate effort in a corresponding clip element, such as an internal thread 9 (or other locking element) of the clip element 5 from the plate element 2 . 2a . 2 B or the plate element 3 bring and remove again.

In 4 is the interaction of fasteners (screws 7 ) and clip elements 5 illustrated. The single plates (plate elements 2 . 2a and 3 ) and clip elements 5 are shown here cut. The clip elements 5 the plate elements 2 . 2a have an upper internal thread 9 , which in terms of pitch, nominal diameter and length with a head 11 the screw 7 corresponds. A lower internal thread 10 of the clip element 5 has a pitch, which is the thread pitch of the shaft 12 (Screw 7 ) is identical. However, acts between shaft 12 and the internal thread 10 an interference fit, allowing the insertion of the screw 7 in the clip device 5 (or through them) consequently to a spreading of the bead 8th of the clip element 5 leads. This will between the bead 8th and the thread 10 , depending on the version ( 5 - 7 ) produces an increased adhesion or a combination of positive and non-positive connection such that the plate elements 2 . 2a . 3 are firmly connected. Only by removing all the plate elements 2 . 2a . 3 penetrating screws 7 become the latches of the clip elements 5 again "released" and thereby the individual plates (plate elements 2 . 2a . 3 ) again detachable from each other.

For local decoupling of superimposed plate elements 2 . 2a . 3 then is the bruised bead 8th the clip connection of the clip elements 5 with a suitable tool, especially a pair of pliers to remove. From the screw 7 At this point, no more force on the plate elements 2 . 2a . 3 be transmitted.

The 5 to 9 lead examples of different design of the clip elements 5 on, with two corresponding clip elements 5 are shown.

In 5 is the bead 8th carried out such that located on the circumference of lamellae 13 in the internal thread 9 from the corresponding clip element 5 (or internal thread of the threaded hole 6 ) claw positively. The insertion of the screw 7 causes in this case the adhesion between the clip elements 5 in addition to the existing form fit.

In 6 is the bead 8th as a slotted ring 14 with smooth outside in interference fit to the internal thread 9 from the corresponding clip element 5 (or internal thread of the threaded hole 6 ), so that the introduction of the bead 8th in the said internal thread leads to a frictional connection. By inserting a fastener (screw 7 ) the adhesion is increased to the insolubility of the clip elements.

The embodiment in 7 corresponds in its basic operation of the embodiment 5 , however, represents a production less demanding variant in which instead of several slats 13 only a circumferential lip 15 for locking in the internal thread 9 from the corresponding clip element 5 (or in the internal thread of the threaded hole 6 ) is provided.

In the embodiments 8th and 9 is on the internal thread 9 dispensed with in favor of a larger friction surface. Instead, the bead points 8th an interference fit with a ring inner surface 16 on. In 8th the connection between the clip elements takes place 5 exclusively non-positive. at 7 ensures the combination of the circumferential lip 15 with an undercut 17 for an initial positive fit, which by inserting a fastener (screw 7 ) is supplemented by a traction.

10 shows a way to connect plate elements 3 with threaded holes 6 (see. 1 ) only by the penetrating fasteners (screw 7 or threaded pin 18 ). To have the threaded holes 6 the plate elements 3 identical internal thread 19 , each with the corresponding external thread of the fasteners (screw 7 or threaded pin 18 ) correspond. Be used for the implant anchorage on the bone set screws 18 used, then invariably all of these penetrated plate elements 3 connected with each other. For implant anchoring by means of screws 7 is the number of plate elements 3 , which can be connected to each other, each by the length of a threaded screw head 7a the screw 7 certainly.

Both the set screws 18 as well as the screw heads 7a are at their upper end with a threaded spout 20 which prevents the fasteners from being too deep in the plate element 3 be screwed.

11 shows a way to connect plate elements 21 with through holes 4 and notches 22 through this penetrating expansion dowel 23a . 23b (see also 12 and 13 ). These are the expansion dowels 23a . 23b non-positively in the through holes 4 the plate elements 21 brought in. By introducing fasteners, such as screws 7 , in this expansion dowel 23a . 23b the adhesion is increased to the insolubility of the plate-dowel connection. To turn the dowels 23a . 23b when inserting the screws 7 or other screw elements, these are in the range of their dowel head 25 with at least one flat 26 provided, the form-fitting and arresting in the notches 22 on top of the plate elements 21 intervenes.

For the technical implementation of expansion anchors 23a . 23b Both metallic (titanium, surgical steel, etc.) and non-metallic materials (polyether ketone, polyethylene, etc.) come into consideration.

When using polymeric materials as the material for the expansion dowel 23a shows 12 an advantageous embodiment. Here is a dowel inner surface 24a as a smooth, the thread core diameter of the fastener (for example, screw 7 as a threaded element, cf. 11 ) corresponding through bore executed. When inserting the screw 7 this itself cuts its thread into the dowel material (dowel inner surface 24a ) and thereby causes by lateral displacement of the relatively elastic material of the expansion anchor 23a an increase in the adhesion between the expansible plug 23a and the through hole 4 the plate elements 21 ,

If a rather rigid material, such as metal, is used as the dowel material, the in 13 illustrated embodiment of the expansion anchor 23b with a side slot 27 advantageous. In this variant is a dowel inner surface 24b with a fastener (for example, screw 7 as a threaded element, cf. 11 ) provided corresponding thread, the core diameter, however, is kept slightly smaller than the core diameter of the fastener, so that by introducing the fastener of the expansion dowel 23b mechanically expanded and so the adhesion between the expansible plug 23b and the through hole 4 the plate elements 21 is increased.

LIST OF REFERENCE NUMBERS

1, 1a

plate implant

2, 2a, 2b

Plate element with through holes 4

3

Plate element with threaded hole 6

4

Through hole of the plate elements 2 . 2a . 2 B

5

Clip element on underside of the plate elements 2 . 2a . 2 B

6

Threaded hole from the plate element 3

7

screw

7a

screw head

8th

Bead as a clip element

9

Internal thread of the clip element 5 (above)

10

Internal thread of the clip element 5 (below)

11

Head of the screw 7

12

Shaft of the screw 7

13

Slats of the bead 8th

14

slotted ring 14 (with a smooth outside)

15

circumferential lip

16

Ring internal surface

17

undercut

18

Set screw

19

Internal thread of the threaded hole 6 from the plate element 3

20

Thread outlet (screw 7 and threaded pin 18 )

21

Plate element for dowel connection

22

notch

23a, 23b

expansion anchor

24a, 24b

Dowel inner surface

25

dowel head

26

flattening

27

slot

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

• US 3695259A [0002]
• WO 2008/077482 A1 [0004]
• US6001099A [0004]
• US 4683878 A [0004]
• US 4955886 A [0004]
• EP 449867 A1 [0005]
• DE 102006018867 B3 [0005]

Claims (10)

Device for plate osteosynthesis, consisting of a plate system ( 1 . 1a ), which consists of several use-specific one above the other lockable flat or curved single plates ( 2 . 2a . 2 B . 3 . 21 ) of different shape and size, wherein at each and / or for each individual plate ( 2 . 2a . 2 B . 3 . 21 ) each arranged in an identical grid force and / or positive-acting fastening elements ( 4 . 5 . 6 . 7 . 18 . 23a . 23b ) are provided. Device according to claim 1, characterized in that the individual plates ( 2 . 2a . 2 B . 3 . 21 ) each have different lengths. Device according to claim 1, characterized in that the individual plates ( 2 . 2a . 2 B . 3 . 21 ) each have different thickness. Device according to claim 1, characterized in that the fastening elements ( 4 . 5 . 6 . 7 . 18 . 23a . 23b ) are designed for releasable connections, such as screw, latch or clip connections. Device according to claim 4, characterized in that the individual plates ( 2 . 2a . 2 B . 3 ) for forming the locking elements as a releasable clip connection in each case arranged in the grid through holes ( 4 . 6 ) and on its lower and / or upper side in the corresponding raster clip elements ( 5 ), for example, continuous or slotted protruding ring elements ( 8th . 14 ), which in through holes assigned by the grid ( 4 . 6 ) and / or clip elements ( 5 ) of the respectively adjacent single plate ( 2 . 2a . 2 B . 3 ) engage in a locking manner. Device according to claim 4, characterized in that the individual plates ( 3 ) for forming the locking elements as a detachable screw in each case arranged in grid tapped holes ( 6 . 19 ) into which screws ( 7 ) or threaded pins ( 18 ) for locking the individual plates ( 3 ) intervene. Device according to claim 4, characterized in that the individual plates ( 21 ) to form the locking elements as a detachable dowel connection each arranged in the grid through holes ( 4 ), in which dowels, such as expansion dowels ( 23a . 23b ), for locking the individual plates ( 21 ) intervene. Device according to claim 7, characterized in that the dowels ( 23a ) consist of pressure-elastic material such as plastic material, such as polyether ketone or polyethylene. Device according to claim 7, characterized in that the dowels ( 23b ) consist of an at least slightly pressure-elastic material such as metal, such as titanium or surgical steel. Device according to claim 7, characterized in that the dowels ( 23a . 23b ) and / or the individual plates ( 21 ) at least one lagearretierendes element, for example, a flattening ( 26 ) and a corresponding notch ( 22 ) exhibit.

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