EP1385436A1

EP1385436A1 - Distractor

Info

Publication number: EP1385436A1
Application number: EP03745735A
Authority: EP
Inventors: Joachim Pfefferle; Dominik Burkhart; Peter Scheuble; Andreas Stricker
Original assignee: Medartis AG
Current assignee: Medartis AG
Priority date: 2002-04-09
Filing date: 2003-03-28
Publication date: 2004-02-04
Also published as: JP2005522244A; WO2003084414A1; AU2003215476A1; US20050119659A1

Abstract

The invention relates to a distractor (1) comprising a first fixing means (3), a second fixing means (2), and an adjustment element (4, 40, 41) which is connected to the first fixing means (3) and the second fixing means (2). The first fixing means (3) and the adjustment element (4, 40, 41) are embodied or connected (33, 51, 52) to each other in such a way that when the adjustment element (4, 40, 41) is actuated, the second fixing means (2) which can be fixed to the mobile bone fragment can be pivoted out of the plane in which it can be fixed to the bone fragment.

Description

distractor

The invention relates to a distractor according to the preamble of the independent claim.

Distractors are used in osteosynthesis / osteogenesis, particularly in the mouth, jaw and face area. A special area of application for such distractors is in the front area of the jaw, e.g. of the lower jaw (mandible), or also in the front area of the upper jaw (maxilla). For example, if the

Lower jaw bone in the front area is atrophic, or if a segment of the lower jaw had to be resected due to malignant neoplasms, or even after a lower jaw trauma, it is favorable for denture reconstruction with the help of dental implants or prostheses if the alveolar ridge of the lower jaw in the front area is restored can be built up before the implants are placed.

Typically, this is done by mobilizing the upper bone segment (osteotomy, corticotomy) in the front area of the lower jaw - where the bone defect is to be repaired. With the help of a distractor, the mobilized bone segment is then raised slightly from the fixed lower jaw bone. Due to the osteoinductive effect of the distraction, new bones are formed between the raised bone segment and the fixed bone. The mobile bone segment is raised in small steps until the alveolar ridge is rebuilt. The bony

Gingiva covering the alveolar ridge is also lifted by the distraction. Previously known distractors that are used in such applications typically include two

Bone plates (typically so-called mini plates), one of which is attached (e.g. by screwing) to the bone segment mobilized (by osteotomy / corticotomy) and the other to the stationary mandible. An adjustment organ (distraction spindle) is connected to both bone plates. The distance between the two bone plates can be changed with the help of the adjusting element. With appropriate actuation of the adjusting member, the bone plate that is attached to the mobilized bone segment is moved linearly along the spindle axis away from that bone plate that is attached to the fixed mandible bone.

This tried and tested way of distraction is, however, in need of improvement insofar as the distraction only takes place strictly in the direction of the spindle axis. However, since the lower jaw has a certain natural curvature - not here from the curvature of the

Lower jaw in the horizontal plane, but rather the curvature of the lower jaw (when viewed from the front) in the sagittal planes - this curvature of the lower jaw cannot be optimally reproduced with the known distractors, because distraction can only be carried out strictly in the direction of the spindle axis , In addition, the tensile strength of the lip ribbon also acts in the front area, making it particularly difficult to rebuild the alveolar ridge as faithfully as possible. Especially in the front area of the lower jaw (and also in the front area of the upper jaw), a reconstruction of the alveolar ridge that is as lifelike as possible is highly desirable.

This is where the present invention comes in, whose task it is is to propose a distractor with which it should be possible to enable the best possible shaping of the bone to be built during distraction osteogenesis, and in particular to allow the natural jaw curve to be reproduced when an alveolar ridge of the lower or upper jaw is rebuilt. The distractor should preferably be simple in terms of production technology.

This object is achieved by the distractor according to the invention, as is characterized by the features of the independent patent claim. Particularly advantageous refinements of the distractor according to the invention result from the features of the dependent claims.

In particular, the distractor comprises first fastening means for fastening to a first, fixed bone piece, as well as second fastening means for fastening to a second bone piece, which can be moved relative to the first bone piece, in a defined plane. The distractor furthermore comprises an adjusting member which is connected to the first fastening means on the one hand and to the second fastening means on the other hand, and the actuation of which allows the distance between the first fastening means and the second fastening means to be changed from one another. As a result, the pieces of bone to which the first and second fastening means can be fastened can be moved away from or towards one another. The first fastening means and the adjusting element are designed or connected to one another such that when the adjusting element is actuated, the second fastening means which can be fastened to the movable bone piece can be pivoted out of the plane in which they can be fastened to the bone piece. This pivotability of the second fastening means out of the plane in which they are fastened to the movable bone piece allows the natural structure of the alveolar ridge, for example of the lower jaw, because during the bone build-up (osteogenesis) the direction in which the movable ( bone piece mobilized by osteotomy or corticotomy is distracted relative to the fixed (immobile) bone piece. In this way, the natural curvature of the jaw can be taken into account and reproduced as faithfully as possible during osteogenesis.

In one embodiment of the distractor according to the invention, the first fastening means comprise a first bone plate and the second fastening means comprise a second bone plate, the adjusting member being connected to the first bone plate on the one hand and to the second bone plate on the other hand. Fastening with the help of bone plates (in particular with so-called mini plates) is a particularly reliable type of fastening, which can also be mastered from the operational side. In principle, an attachment by means of other suitable means (e.g. razor wires, etc.) could also be considered, although attachment by means of bone plates is preferred.

The first bone plate can be designed such that it has a plate longitudinal axis, the second bone plate being pivotable about this plate longitudinal axis or about an axis parallel to it. This pivotability of the second bone plate around the longitudinal axis of the first bone plate or around an axis parallel to it allows - as already above mentioned - the natural structure of the alveolar ridge, for example, the lower jaw, because during the bone build-up (osteogenesis), the direction in which the movable (mobilized) bone piece is distracted relative to the stationary (immobile) bone piece can be changed by distraction. This allows the natural curvature of the jaw to be reproduced as realistically as possible during osteogenesis.

In an advantageous embodiment of the distractor according to the invention, the adjusting member is connected to the first fastening means or the first bone plate in the manner of a hinge. The hinge-like connection defines the pivot axis about which the second fastening means or the second bone plate can be pivoted.

In an advantageous development of the distractor according to the invention, the hinge is designed as a film hinge. This type of hinge design is particularly simple in terms of manufacturing technology.

In a further advantageous development of the distractor according to the invention, a fastening element is provided which is connected to the first fastening means or the first bone plate via the hinge and which has a rigid connection to the second fastening means or to the second bone plate via the adjusting element. The adjusting member comprises a pivoting member for pivoting the second fastening means or the second bone plate, which is connected to the fastening element on the one hand and to the first fastening means or the first bone plate on the other hand. Two or more thin webs, which form the hinge, can be provided between the fastening element and the first fastening means or the first bone plate. Two or more webs prevent the fastening element from tilting and thus prevent the second fastening means or the second bone plate from tilting within their plane.

Fastening element and hinge can be integrally formed on the first fastening element or the first bone plate, which simplifies the production in that the bone plate, fastening element and, in the case of the webs, the webs can be produced in a common manufacturing process and cannot be produced separately and then in a suitable manner Way to be connected.

In a further development of the distractor according to the invention, the adjustment member comprises a distraction member for linearly changing the distance between the first and second fastening means or the first and second bone plates, and the swivel member for pivoting the second bone plate, a rigid connection being established between the distraction member and the swivel member. There is a first holding element on the fastening element and the first one

Fastening means or the first bone plate, a second holding element is attached. The swivel member has a threaded spindle and the first holding element, which is fastened to the fastening element, has a through bore with a thread for receiving the threaded spindle. The threaded spindle is immovably received in the second holding element, which is fastened to the first fastening means or to the first bone plate, in the direction of the spindle axis. This Further development represents a constructively advantageous and technically advantageous variant of the distractor according to the invention. It is also advantageous insofar as the "overall height" of the distractor is maintained when pivoting and does not increase.

In a further embodiment of the distractor according to the invention, the hinge is designed such that the second fastening means or the second bone plate relative to the first

Fastening means or to the first bone plate by an amount of up to 30 °, preferably up to 15 °, is pivotable (both pivoting directions). This area is large enough to reproduce the natural curvatures, especially in the jaw area.

The distractor according to the invention is preferably made of titanium or another biocompatible material so that it does not cause any reactions in the body.

Further advantageous refinements of the distractor according to the invention result from the following description of an advantageous exemplary embodiment with the aid of the drawing. Show it:

1 shows an embodiment of a distractor according to the invention in front view,

2 the distractor from FIG. 1 in rear view,

3 shows the distractor from FIG. 1 in a perspective view from behind, 4 shows the distractor from FIG. 1 in a perspective view from the front (partially cut)

5 shows the distractor from FIG. 1 in a side view in neutral position (partially cut),

Fig.6-8 the distractor of Fig. 1 in three different pivot positions, and

9-11 the distractor from FIG. 1 in three further pivot positions.

1 shows an embodiment of a distractor 1 according to the invention in a front view, as can be used in particular in the front area of the lower or upper jaw. The distractor 1 comprises a first bone plate 3 and a second bone plate 2, each of which is preferably designed as an elongated mini plate. The second bone plate 2 extends in the direction of its longitudinal axis 20. It has a plurality of eyelets 21, through which bone screws (not shown) can be screwed into the movable bone segment in order to fasten them to the movable bone segment. For this purpose, the plate holes 210 can be designed as through holes, they can have a thread that interacts with a corresponding screw thread, or they can have an engagement contour that is different from a thread for blocking the

Have bone screw. Such an engagement contour and its mode of operation is described, for example, in WO-A-00/66012. Between the eyelets 21 of the bone plate 2, webs 22 are provided, which separate (cut off) and / or allow the bone plate 2 to bend onto the respective outer contour of the movable bone segment.

The first bone plate 3 is also elongated and extends in the direction of its longitudinal axis 30. In principle, the first bone plate 3 can also have the same shape as the second bone plate 2. The first bone plate 3 also has a plurality of eyes 31, in which plate holes 310 are provided, which in turn can be designed as through holes, can have a thread for cooperation with a corresponding screw thread, or can have a different engagement thread than a thread, as described for example in the aforementioned WO-A-00/66012. Crosspieces 32 are provided between the eyelets 31, so that the first bone plate can also be easily separated (cut off) and / or bent onto the jawbone (to be precise on a fixed bone segment of the jawbone).

The distractor 1 further comprises an adjustment member 4, which in turn comprises a separate swivel member 40 and a separate distraction member 41. Swivel member 40 and distraction member 41 are rigidly connected to one another. A plate 23 (see, for example, FIGS. 2, 3) is provided on the second bone plate 2, with which the distraction organ 41 (distraction spindle) is firmly connected, for example welded on.

A fastening element is provided on the first bone plate 3, which here has the shape of a plate 33 (see, for example, FIGS. 2 and 3) which is connected to the first bone plate 3 in the manner of a hinge. The illustrated embodiment is in the hinge around a film hinge, which here has two thin webs 51 and 52. Two such webs 51 and 52 are advantageous insofar as this makes it very difficult, if not prevented, to tilt the second bone plate 2 in the plate plane (here the paper plane). For this purpose, more than two webs can also be provided, but in principle a single web would suffice to fulfill the hinge function (which could then be made somewhat wider than in the two-web variant shown). The hinge could also be designed differently than a film hinge, as long as it only ensures the hinge function. With the help of the hinge, here with the help of the webs 51 and 52, the second bone plate 2 is one to the in the embodiment shown

Longitudinal plate axis 30 of the first bone plate 3 parallel axis 300 pivotable. This means that the second bone plate 2 in FIG. 1 can be pivoted forwards or backwards out of the paper plane around the axis 300, as will be explained in more detail below.

A first holding element 61 is provided on the fastening element - the plate 33 - and a second holding element 62 is provided on the first bone plate 3, each of which can be manufactured as separate parts and fastened to the plate 33 or to the bone plate 3, e.g. by being welded on. In the first holding element 61, a through hole with a thread 610 (see FIG. 5) is provided, into which the thread of a threaded spindle 400 of the swivel member 40 can engage. The second

Holding element 62 has a recess 620 (see FIG. 4, FIG. 5), in which the distal end of the threaded spindle 400 is received so that it cannot move in the direction of the spindle axis (see FIG. 1). However, the distal end is the Otherwise, threaded spindle 400 can, within certain limits, be displaced essentially forwards or backwards in recess 620, as will become apparent further below from the description of the mode of operation of distractor 1.

The mode of operation of the distractor 1, in particular when pivoting, will be explained below with reference to FIGS. 6-8 and 9-11. The pivoting about the axis 300 (see FIG. 1) is primarily dealt with, that is to say the change in direction, while the linear distraction - that is to say the change in the distance between the two bone plates from one another, in a known manner by actuating the distraction member 41 (distraction spindle ) he follows.

To understand the functioning of the distractor during the pivoting, consider again FIG. 5, in which the distractor 1 is in the neutral position (that is, not pivoted). In contrast to this neutral position, the distractor in FIG. 6 is in a position in which the plate 33 is pivoted relative to its neutral position by an angle of, for example, ci = 5 °. This pivoting can be achieved by actuating the pivot member 40, which can be done here with the aid of a suitable key (not shown) which engages the polygonal head 401 of the threaded spindle 400, so that the threaded spindle 400 can be rotated. When turning the polygonal head 401 of the threaded spindle, the threaded spindle 400 tries - by the interaction of the thread of the threaded spindle 400 with the thread 610 of the first holding element 61 - to increase the distance d ₀ between the first holding element 61 and the second holding element 62 in the axial direction. But that's in the direction of Course of the spindle axis in the neutral position is not possible because the distal end of the threaded spindle 400, as already described, is immovably caught in the recess 620 of the second holding element 62 in the axial direction. On the other hand, by rotating the threaded spindle 400, the distance do, which exists in the neutral position between the first holding element 61 and the second holding element 62, must be increased, otherwise the threaded spindle 400 would not be able to be rotated when the distal end was caught. Since the webs 51 and 52 of the

Film hinge are bendable, the webs 51 and 52 are bent by turning the threaded spindle 400, the plate 33 with the attached first holding element 61 is thus pivoted about the axis of rotation 300 (see FIG. 1). This increases the distance d ₀ between the two holding elements 61 and 62 in the neutral position (FIG. 5) to the distance di in the position according to FIG. 6 (pivoting of the spindle axis by 5 °). The distal end of the threaded spindle slides slightly outwards in the recess 620 of the second holding element 62.

Upon further rotation of the threaded spindle 400, the plate 33 with the first holding element 61 attached to it reaches the position shown in FIG. 7, in which the

Plate 33 is pivoted about the angle α = 10 ° relative to the neutral position about the axis 300 (Fig. 1). The distance between the first holding element 61 and the second holding element 62 in the direction of the spindle axis is increased to the distance d ₂ .

If the threaded spindle 400 is rotated further, the plate 33 finally arrives with the first holding element 61 attached to it in the position shown in FIG which the plate 33 is pivoted by the angle α ₃ = 15 ° relative to the neutral position about the axis 300 (see FIG. 1). The distance between the first holding element 61 and the second holding element 62 in the direction of the spindle axis is increased to the distance d ₃ .

The pivoting of the plate 33 in the other direction functions in the same way, as can be seen in a simple manner in FIGS. 9-11, where there the distance d ₀ (neutral position according to FIG. 5) between the first holding element 61 and the second holding element 62 with a swivel angle α ₄ = 5 ° of the plate 33 is first reduced to the distance d ₄ , which distance is further reduced with a swivel angle of α ₅ = 10 ° to the distance ds, and which distance finally with a swivel angle of αs = 15 ° is reduced to the distance d ₆ .

It is particularly advantageous in the distractor 1 according to the invention that the individual parts, namely the

Bone plates 2 and 3 together with the plate 33 and the webs 51 and 52, furthermore the holding elements 61 and 62, as well as the swivel member 40 and the distraction member 41 can be produced separately in a simple and reliable manner and can be joined together, for example by means of welding, so that from the manufacturing side the distractor according to the invention is easy to control.

Titanium, which is known to be compatible with the body, is particularly suitable as the material for the individual parts. Alternatively, other biocompatible materials can also be used, and bioabsorbable materials can also be considered.

Claims

claims

1. Distractor (1) for osteogenesis, in particular in the front area of the lower or upper jaw, with first fastening means (3) for fastening to a first, fixed piece of bone, and with a second one

Fastening means (2) for fastening to a second bone piece that is movable relative to the first bone piece, in a defined plane, as well as with an adjusting element (4, 40, 41), which is connected to the first fastening means (3) on the one hand and to the second fastening means ( 2) is connected on the other hand and by its actuation the distance of the first fastening means (3) and the second fastening means (2) from one another can be changed, whereby the bone pieces to which the first (3) and second (2) fastening means can be fastened move away from each other or can be moved towards one another, characterized in that the first fastening means (3) and the adjusting element (4, 40, 41) are designed or connected to one another such that when the adjusting element (4, 40, 41) is actuated, the the movable bone piece attachable second

Fastening means (2) can be pivoted out of the plane in which they can be fastened to the bone piece.

2. Distractor according to claim 1, in which the first fastening means comprise a first bone plate (3), and in which the second fastening means comprise a second bone plate (2), the adjusting member (4, 40, 41) with the first bone plate (3 ) on the one hand and with the second bone plate (2) on the other hand.

3. Distractor according to claim 2, wherein the first bone plate (3) has a plate longitudinal axis (30) and the second bone plate (2) can be pivoted about the longitudinal axis of the plate (30) or about an axis (300) parallel to it.

4. Distractor according to one of the previous ones

Claims, in which the adjusting member (4, 40, 41) is connected to the first fastening means or to the first bone plate (3) in the manner of a hinge.

5. distractor according to claim 4, wherein the

Hinge is designed as a film hinge (51, 52).

6. Distractor according to claim 4 or 5, in which a fastening element (33) is provided, which is connected via the hinge (51, 52) to the first fastening means or the first bone plate (3), and which via the adjusting element (4 , 40, 41) has a rigid connection to the second fastening means or the second bone plate (2), and in which distractor the adjusting element (4, 40, 41) also has a pivoting element (40) for pivoting the second fastening means or the second Bone plate (2), which is connected to the fastening element (33) on the one hand and to the first fastening means or the first bone plate (3) on the other hand.

7. Distractor according to claim 6, wherein two or more thin webs (51, 52) are provided between the fastening element (33) and the first fastening means or the first bone plate (3), which form the hinge.

8. Distractor according to claim 6 or 7, in which the fastening element (33) and the hinge (51, 52) are integrally formed on the first fastening means or the first bone plate (3).

9. distractor according to one of claims 6 to 8, wherein the adjusting member (4) a Distraktionsorgan (41) for the linear change in the distance of the first and second ^■ fastening means and the first (3) and second (2) comprises bone plate and the pivot member ( 40) for pivoting the second fastening means or the second bone plate (2), there being a rigid connection between the distraction member (41) and the pivoting member (40), in which distractor also a first holding element (61) is attached to the fastening element (33) and a second holding element (62) is fastened to the first fastening means or the first bone plate (3), in which distractor the pivoting element (40) furthermore a threaded spindle (400) and the first holding element (61), which is attached to the fastening element (33 ) has a through hole with a thread (610) for receiving the threaded spindle (400), and in which

Finally, the distractor receives the threaded spindle (400) in the second holding element (62), which is fastened to the first fastening means or the first bone plate (3), so that it cannot move in the direction of the spindle axis.

10. Distractor according to one of claims 4 to 9, in which the hinge (51, 52) is designed such that the second fastening means or the second bone plate (2) relative to the first fastening means or to the first

Bone plate (3) can be pivoted by an amount (ci to a_) of up to 30 °, preferably up to 15 °.

11. Distractor according to one of the preceding claims, which is made of titanium or another biocompatible material.