DE102010015687A1 - Distraction device for distraction osteogenesis of patient, has guide rail directly connected with magnets e.g. permanent magnets, by drive mechanism, where forces for moving guide rails are transferred against each other by magnets - Google Patents

Abstract

The device has two anchor plates (1, 2) which are arranged parallel to each other or aligned together. Two guide rails (3, 4) are connected with the anchor plates and are aligned vertical to the anchor plates. The guide rails are moved against each other and are arranged parallel together. A driving mechanism (5) releases or controls motion of the guide rails against each other. One of the guide rails is directly connected with magnets (6) e.g. permanent magnets or electrical magnets, by the mechanism, and forces for moving the guide rails are transferred against each other by the magnets. An independent claim is also included for a method for performing callus distraction.

Description

The invention relates to a distraction device for Kallusdistraktion, consisting of two anchor plates which are arranged approximately parallel to each other or in alignment and two guide rails, which are each connected to an anchor plate and which are aligned approximately perpendicular to the anchor plates and which are movable against each other and which are arranged parallel to each other and a drive mechanism that triggers or controls the movement of the two guide rails against each other.

As early as 1889, Hopkins and Penrose lengthened a bone intraoperatively by inserting a bone block taken elsewhere (quoted after PB Magnuson: Lengthening shortend bones of the leg by operation. Ivory screws with removable heads as a means of holding the two bones fragments. In SGO: Surgery Gynecolgy and Obstetrics, No. 17, 1913, pages 63-71 )

However, these and other surgical techniques at the turn of the 19th and 20th centuries had a very high complication rate, especially during bone healing. Unfortunately, the target of building new bone mass on the operated bone was unfortunately often not achieved. In particular, infections delayed the ingrowth of the transplanted bones. In extreme cases, the introduced bone even had to be removed and unpleasant wounds were left behind.

An essential development step was the method of callus distraction, also called distraction osteogenesis, introduced in 1988 by the Russian orthopedist Gavril Ilizarov. It is a surgical procedure for bone lengthening, in which the bone to be lengthened is surgically severed and the two halves are slowly and continuously moved apart along their longitudinal axis for weeks by means of a so-called external fixator. Between the two halves moving away from each other new bone substance is formed.

This fixator Externe consists z. As for the extension of tubular bones of metal rods, Ilizarov introduced through the skin of the patient into the two, separate bone parts and the other side protruded outward. In a simple variant, two metal bars each were struck in a criss-cross manner into the ends of the two halves of the bone and connected at each of their two ends to a ring which led around the outside of the bone.

Between both rings mechanical connections were built in, which took over the mechanical load bearing function of the bone during the phase of primary callus formation. After a phase of ingrowth of about 1 week, distraction then began by uniformly extending the connecting elements between the two rings with a distraction rate of 1 mm per day and a distraction frequency of up to 4 adjustments per day, that is, at least 0.25 mm at each adjustment stroke. As a result, self-healing forces of the bone are activated, so that at the point of separation new callus tissue is continuously formed and the bone increases at this rate.

On this basis, distraction osteogenesis has become an important therapy method in oral and maxillofacial surgery. The method is used in particular to construct edentulous or tooth-bearing alveolar process segments and highly atrophic mandibles vertically in the anterior or posterior region or in the region of the entire mandible.

For this purpose, a bone segment covering the reconstruction area is surgically separated from the residual bone and a distraction device is inserted between the bone segment and the residual bone, with which the two bones are continuously displaced against each other. Due to the permanent displacement of the bone segment, new callus is continuously formed between the shafts of the displaced and the fixed bone, creating new bone tissue. The smaller the distraction steps are, the more intense is the formation of callus. Because of this experience, continuous distraction appears optimal.

An important advantage of this method is that not only new bone is formed, but also the surrounding soft tissue is continuously stretched and increased. This histogenesis contributes significantly to the vitality of the displaced bone segment and thus to the reduction of infection risks and to a rapid healing.

The patent describes the current state of the art EP 1 489 979 a distractor, which consists of two mutually displaceable armature plates, on each of which a guide rail is arranged. The two anchor plates extend at least parallel to each other or even aligned with each other in the initial state. On each anchor plate is approximately vertically mounted a guide rail, which can be moved by means of a drive mechanism relative to the other guide rail. As a result, a uniform removal of the two anchor plates is achieved from each other.

The EP 1 498 979 describes as a drive mechanism at the free end of the two guide rails each have a thread which is complementary to the other. On one guide rail, the thread is firmly formed, on the other guide rail a complementary thread is rotatably mounted. By twisting this thread, it moves like the nut on a screw in the longitudinal direction and thus moves the attached thereto guide rail relative to the other, thereby increasing the distance between the two anchor plates.

The smaller the pitch of the thread is chosen, the greater the required twist of the thread for each step of the distraction.

In order to twist the thread, it protrudes from the bone to be enlarged and is at its end by means of a tool - such. B. a screwdriver or a fork wrench - moves on.

This movement is carried out in the simplest case manually by the manual attachment of a tool. Alternatively, however, electric drives are known to ensure a uniform and regular adjustment.

So describes z. B. the patent application US 2008/0234 554 Two circular bone carriers according to Ilizarov, each carrying crosswise arranged rods the end of the bone to be elongated. These two rings outside of the bone to be elongated are connected to each other by at least three carriers, which are extendable by electric motors.

But even this distractor still has the massive problem that the mechanical holding element is guided from the outside through the skin of the patient and through his soft tissue into the bone. With proper hygiene, each of these penetrations has a chance of ingrowth into the skin and into the soft tissue as well as into the bones.

Nevertheless, any passageway of a wearer or pin through skin and soft tissue remains a potential gateway to contamination. Inflammations generated thereby are known as pin-track infection of the soft tissues around the insertion sites of the pins. Not only are they a complaint to the patient, but the direct connection of the body surface to the bone can spread the inflammation to the newly formed callus or to the zone of callus still to be formed. The infection of the bone leads to osteomyelitis, also called osteitis. When an inflammatory focus spreads so far, most of the procedure is obsolete.

The invention is based on this background, the task of developing a distraction, in which the risk of infection due to the entering through the skin supporting elements at least minimized, ideally, however, is eliminated.

As a solution to this problem, the invention teaches that at least one of the two guide rails are connected directly or via the drive mechanism with at least one magnet, via the force for movement of the guide rails relative to each other is transferable.

The essential feature of the invention is therefore to replace the previous mechanical transmission of kinetic energy to the anchor plates of the distractor by a magnetic transmission. This opens up the chance, from the outside of the patient through his skin or through his gums, of transmitting contactless energy to the distraction device, which is sufficient to remove the two anchor plates with the required frequency and the recommended very small steps from each other.

This eliminates all previously necessary openings in the skin and thus any related risk of infection. Experience has shown that infections are the most common complication of distraction osteogenesis according to the prior art. And these problems are intensifying at the moment, as more and more strains of bacteria that have been classified as "defeated" up to years ago, like Staphylococcus aureus or Escherichia coli, which are multiresistant and can no longer be controlled with currently available antibiotics.

Therefore, the invention in practice is a tremendous progress, since the most serious problem so far in distraction osteogenesis, namely the wound healing infections, is eliminated.

Further advantages are that the risk of possible scars in the operating area is reduced and the newly formed callus achieves an increased strength.

It should be noted, of course, that any additional accessories to the distraction device under the skin requires a corresponding operational effort when inserting and also the space required for it must be created.

The basic features for all variants of a jawbone are described below using the example of distraction osteogenesis of the jawbone Distraction device according to the invention are explained and various embodiments are illustrated.

At the beginning, an osteotomy slit is always milled into the bone to be distracted, which separates a movable bone part from the remaining, fixed bone parts. Therefore, this slot is bicortical, ie from one edge zone of the bone to its opposite, other edge zone. In this slot, the two anchor plates are inserted. This is only possible if perpendicular to this slot another slot is milled, in which the two guide rails can be inserted, which are aligned perpendicular to the anchor plate. This slot is monocortical because it cuts through only a marginal zone of the bone.

In order to dimension this second slot as small as possible, the invention proposes that the first, outer guide rail surrounds the second, inner guide rail, which is telescopically displaceable relative to the outer guide rail. This also ensures that within the slot no relative movement of a guide rail against the bone is required.

It is an essential and absolutely indispensable feature of the distractor, that - apart from the up to four adjustment strokes per day - the two anchor plates never move against each other. It would be fatal if the anchor plates would move towards each other again and thereby burden the recently formed callus or even demolish it again.

In order to prevent this, the invention proposes, as a variant embodiment of the drive mechanism, that the two guide rails are secured against unintentional displacement by a toothed rack with a pawl latching resiliently therein. In this case, in one variant, the inclination of the flanks of the teeth on the rack and the orientation of the pawl can be chosen so that the guide rails are displaceable against each other in one direction only. This prevents accidentally moving the two anchor plates back to each other and thereby put the freshly formed callus under impermissible pressure.

Another advantage is that, when moving in the "right direction", but beyond the intended level of displacement, the moment the spring engages, it builds up a torque peak that opposes an actually unwanted, further shift.

With such a variant of the drive technology, the following, in principle very simple movement of the two guide rails against each other is possible:
On both guide rails a permanent magnet is placed within the body tissue and its required range of motion is covered by a non-magnetic and tissue-compatible cap.

After insertion of the distractor into the bone, the cap is covered by a thin layer of skin or a thin layer of gum. This layer can, for. B. before the milling of the slots by some knife cuts partially separated from the rest of the tissue and then folded to the side. After insertion of the distractor, the layer is folded back into its original position and sewn at its edges with the adjacent layer.

Outside of the callus area to be distracted and outside the layer of skin or gums on the caps, a holder is then placed, which carries a third and a fourth magnet, which is the first b. z. w. each have only a very small distance to the second permanent magnet. This distance must be so small that the attraction of the third, movable magnet to the first magnet and the attraction of the fourth magnet to the second magnet are each so large that they "pull along" the first and the second magnet.

Due to the necessary range of motion between the first two permanent magnets and the cap and by the material of the cap and the thickness of the skin layer and the required second range of motion between the skin layer and the third and fourth magnet results in a certain minimum value for the distance between the first and the third magnet and between the second and the fourth magnet. The field strength of the magnets must be dimensioned so large that even on this principle-related minimum distance away sufficient attraction - especially when accelerating - is ensured.

Under these conditions, the distance between the third and the fourth magnet can be changed either manually or by an auxiliary drive on the holder, whereupon the distance between the first and the second permanent magnet on the two guide rails changed accordingly.

In a possible embodiment, the third and the fourth magnet on the holder each consist of a magnetizable core to the a coil is wound. Such an arrangement acts as an electromagnet when current flows through it. The combination of at least one permanent magnet and an electromagnet, which moves the permanent magnet linearly, is known and proven as a "linear motor" in principle in various embodiments and dimensions. Among other things, a design as a stepper motor is possible.

Then, the third and the fourth magnet, each with a current pulse to move the first and / or the second magnet by a structurally predetermined increment on. This increment should be at least a quarter of a millimeter and a maximum of one millimeter in the longitudinal direction.

Such a small step size also requires correspondingly small permanent magnets on the guide rails and matched electromagnets on the holder. Electric drives in such dimensions are well known in the art of clockworks ago.

Alternatively, the magnet may be made of soft iron on the guide rails, in which teeth are formed on the side facing the electromagnets whose spacing corresponds to the desired step length. The soft iron is flowed through during the movement of the magnetic field of the electromagnet and thus also becomes a magnet during the movement.

These variants thus describe a linear drive for the movement of the two guide rails against each other. Its advantage is the very simple construction, which is also very compact.

It should be noted, however, that the linear drive acts directly on the anchor plates via the guide rails. Such a drive is therefore also referred to as direct output. In particular, it requires a correspondingly large feed force at the start, which may require very high currents for a short time. Both the permanent magnets on the guide rails, as well as the complementary electromagnets, as well as their power supply and the corresponding controls are interpreted on this short-term required peak value.

An alternative to such linear drives are rotating drives which can be supplemented as a further alternative with a mechanical transmission. For this embodiment, the two guide rails must be secured against mutual rotation in the longitudinal direction, z. B. by a guide nose or a longitudinal bead in a guide rail, which engages in a longitudinal groove in the respective other guide rail. Alternatively, the entire guide rails may be polygonal or profiled with another non-circular shape.

As a suitable drive mechanism, the invention proposes that at the free end of the outer guide rail, an internal thread is formed coaxially to the longitudinal axis thereof. At the free end of the inner guide rail then an external thread must be formed, which is formed complementary to the internal thread on the other guide rail. One of the two threads must be rotatably connected to the respective guide rail, while the other of the two threads is firmly formed on the respective guide rail or otherwise secured thereto. It is essential that at least one magnet is mounted on the rotatable thread. For the purposes of the invention, the energy is introduced into the distraction device and the displacement of the two guide rods against each other via this magnet or these magnets.

In one embodiment variant, the invention proposes that the magnet or magnets be expanded on the rotatable thread with additional components to form a rotating electric motor. For this purpose, it is proposed to build on the guide rail with the fixed thread an electromagnet, which consists of a magnetizable core, which has only a very small air gap to the magnet on the rotatable thread and is wound around a spool of electric current through a coil.

When this coil is connected to an electrical energy source, it generates a magnetic field that attracts or repels the magnet or magnets on the rotatable thread. As a result, an electric motor is formed, which sets the magnets and the associated rotatable thread in rotation. The stator of this electric motor thus contains at least one coil, each with a core. The rotor of this electric motor consists of at least one magnet - preferably a permanent magnet which is connected to the rotatable. Thread is connected and swings past during rotation of the core or cores in the stator. If, by connecting the stator to an electrical energy source, the rotor is pivoted relative to the stator, the two guide rails are moved relative to one another via the thread.

Such an electric motor can be meaningfully designed as a stepper motor which moves with each current pulse from the power source by exactly one increment. Its advantage is that it remains in its current position when de-energized. From the outside acting forces he braces his nominal torque against, so that a further fixation of the anchor plates usually not required. Only then, if this limit is exceeded, it will continue to jump one increment at a time until the effect of the external forces drops below the rated torque.

This results in a very significant advantage that the stepper motor, an additional position control loop with an additional actual value for the rotation angle is unnecessary.

An indispensable prerequisite for this is, of course, that during the movement, the torque of the stepping motor is sufficient in any case to overcome all opposing forces. Otherwise, although a current pulse would be delivered to the stepper motor, but causes no pivoting of the engine, but only generates heat loss.

Since the aim of the invention is not to provide a firm connection between the callus and the outside of the skin or the gums, the invention proposes, as a variant, to arrange all elements of a distraction device according to the invention below the skin or below the gum. In this embodiment, therefore, the energy source, such. As a lithium-ion battery or other electrical energy storage directly on the distraction device or in the vicinity. Also, the control processor that monitors the connection of the power source to the electric motor must also be placed under the skin, such as a signal transmitter that is mechanically and electrically connected to the control processor and receives the control commands percutaneously and non-contact from a remote control outside the body tissue. During distraction, there is only one remote control left to operate whose signals are received by the signal transmitter and forwarded to the control processor. This then sets in motion in the distraction device integrated electric motor.

The control processor may also be used to store the respectively entered steps of distraction and their timing and to send them outwardly via the signal transmitter, e.g. B. in an evaluation in the remote control to send.

An advantage of the described, rotating drive compared to a linear drive is its overall smaller design and its much lower peak power consumption. Thanks to the mechanical translation of the thread acting as a worm gear, the rotating electric motor only has to apply a correspondingly smaller power than the linear motor.

The work to be performed by the rotating motor increases compared to the direct-acting linear drive by the friction losses in the thread. It makes sense, these friction losses by a low-friction design, such. B. to reduce a Teflon coating of one of the two threads.

Otherwise, the total of two types of drive for the movement to be performed work, of course, the same size, but the rotating motor requires the time required to perform this work considerably longer. The rotating electric motor thus has an overall longer service life.

Since only a very small space is available, especially within the jaw, it is advantageous to make the electric motor as small as possible. For this purpose, it is useful to add in addition to acting as a worm gear thread another gear, z. B. a spur gear or a worm gear or a planetary gear or other gear. An example of a different type of transmission is a Gleitkeilgetriebe or stress wave transmission, which is also known under the English name "Harmonic Drive". Like the planetary gear, it has a ring gear with internal teeth on the outside. Instead of a sun gear and at least one planetary wheel, however, only a so-called "flex spline" rotates in this ring gear. This is a deformable, cylindrical steel bushing with external teeth, which results in a very high gear ratio.

For a further reduction of a distraction device according to the invention, the invention proposes a variant in which - similar to the linear motor already described - the stator of the electric motor is placed outside the tissue and the magnetic fields generated by him through a skin layer or through a layer of the gum and be transferred by a cap over the movable magnet on the rotating magnets of the distraction device. The material of the cap must be non-magnetic and biocompatible so that it can be overgrown by a layer of skin or gums.

Above the skin layer or the gums, the electromagnets of the stator are arranged in a holder. This bracket can, for. B. are supported on at least three adjacent teeth, so that it is fixed stable in the mouth. As a basis for such a holder z. B. serve a casting of the teeth, in which the electromagnetic part of the stator is fitted and installed. If the corresponding phase-shifted currents flow through the coils of the stator, then a rotating magnetic field is generated, which acts on the permanent magnets on a guide rail of the distractor and thereby also causes them to rotate. Because the air gap of such an arrangement has the shape of a disc, such a motor is also referred to as a disc rotor.

As another alternative, a complete electric drive is placed on a previously described holder in the oral cavity, on the output shaft of which at least one coupling magnet is fixed, which rotates with the drive shaft. The coupling magnets serve as a magnetic coupling between the motor in the mouth and the magnets on the guide rail.

They have only a very small distance to the magnets below the gum on the drive mechanism of the distraction device. When the coupling magnet is twisted, it also rotates the first magnet on the distraction device and thus transmits the kinetic energy from the outside through the skin or the gums, ie percutaneously, to the distractor.

If, due to the growing distance between the two anchor plates, the drive mechanism and the magnets lift in the oral cavity relative to the adjacent teeth on which the holder rests, this support must also be increased in parallel with the growth of the callus. This can z. B. be made simply by washers in the strength of the distraction steps. Are also conceivable mechanically or even electric motor driven lifting devices such. As spindles or swiveling eccentric.

Regardless, it makes sense that in the actual distraction stroke, the electric motor for the movement of the second magnet as well as in the subcutaneous embodiment is controlled by a control processor. It is conceivable that in this variant, a signal transmitter is present, which is controlled by a remote control outside the mouth.

In this variant, however, it is also possible that the control and the connection to an external power source via a cable, which is then out of the mouth of the patient out to a corresponding module.

In the following, further details and features of the invention will be explained by way of example. However, this is not intended to limit the invention, but only to explain. It shows in a schematic representation:

1 Longitudinal section through a distraction device with electromagnets outside the body tissue

2 Enlargement of the drive mechanism according to 1 with the magnets

In 1 an inventive distraction device is shown. In the lower part are the two anchor plates 1 . 2 to recognize. The first anchor plate 1 is in this embodiment via a thread with the first guide rail 3 connected, perpendicular to the anchor plate 1 is aligned. Inside the hollow, first guide rail 3 moves in its longitudinal direction, the inner, arranged second guide rail 4 that has a thread with the second anchor plate 2 connected is.

The in 1 shown operating state already shows a clear distance between the two anchor plates 1 . 2 , The upper, free end of the second, inner guide rail 4 with the male thread formed thereon 54 is already half of the internal thread of the mother 53 pushed out. The view in the upper part of the mother 53 shows in comparison with the lower part of the mother 53 that the anchor plates 1 . 2 have already covered half of their maximum possible path.

To understand the basic function of the distraction device according to the invention, the fit into the - not shown here - bone substance will be explained. In the initial state, the two anchor plates touch each other 1 . 2 , They are inserted surgically into a corresponding slot in the bone substance. In the 1 lower, second anchor plate 2 rests on a stationary part of the bone. On the in 1 upper anchor plate 1 is located on the lower part of the bone operatively separated from the lower bone part. In this upper bone part a smaller, running vertically to the first slot second slot is milled, in which the first guide rail 3 together with its head-like drive mechanism 5 is inserted. Both slits are closed again after insertion of the distraction device through a skin layer or gum layer stitched over them.

This layer is in 1 marked in the upper part of the cross-section by an irregular, freehand drawn line. The distraction device located below this line of the skin surface or gum surface is thus completely enclosed in the human tissue.

The 1 and the 2 with the out 1 out enlarged drive mechanism 5 and the magnet 6 . 61 . 62 show very clearly that the distraction device in the area of the cap 8th above the magnets 6 for moving the drive mechanism 5 is covered only with a very thin layer of skin or gum layer through which extends in this embodiment, the magnetic field, that of the two electromagnets 6 in the holder 7 is generated outside the tissue.

Every electromagnet 61 . 62 consists of the magnetizable core 61 to which a coil 62 is wound. Both electromagnets 61 . 62 are in the holder 7 used outside of the fabric. In this holder 7 are also - in 1 just shown as a block - the energy source 91 , the control processor 92 and the signal transmitter 93 built-in.

The signal transmitter 93 receives the command to continue turning the nut 53 , so at least once a day the command for a distraction step of 1 mm or up to four times a day then only ¼ mm to move on. This command is sent to the control processor 92 passed on, the one - in 1 not shown - power semiconductor controls which the electrical energy from the energy source 91 to the two electromagnets 61 . 62 passes.

This control generates in the two electromagnets 61 . 62 a rotating magnetic field, as generated by the stator of an electric motor. This circulating magnetic field is propagated through the skin layer below the holder 7 through and over the cap 8th away into the permanent magnets 6 into it, which are mounted on a disk, which the drive mechanism 5 emotional.

Motors with such a disc-shaped rotor are therefore also referred to as "disc rotor" and are known in principle and proven in numerous embodiments. A special feature of pancake motors is that the so-called "air gap" of the engine - ie the interface between the rotor and the stator - is a plane. Therefore, this motor principle is particularly useful when the rotor of the motor within the tissue and the stator outside of the tissue to be arranged and a flat skin layer or a flat gingival layer as infection-inhibiting intermediate layer should also extend beyond the rotor.

In the 1 and 2 is clearly seen that the cavity of the first guide rail 3 upwards through the cap 8th is covered. Regardless of the guide rail 3 In practice, primarily constructed of metal, which may also have steel components for the purpose of high stability, the cap must 8th consist of a non-magnetic material, so that the magnetic field of the two electromagnets 61 . 62 in the holder 7 as unhindered through the cap 8th can stretch through.

In the embodiment of the 1 and 2 is between the mother 53 on the first guide rail 3 is rotatably mounted and the permanent magnet 6 below the cap 8th that turn to the mother 53 serve, still a gearbox inserted. It consists in the embodiment shown here from the sun gear 55 , which is formed on the disc, which are the two permanent magnets 6 wearing. This disc is rotatable at its outer edge at the upper end of the first guide rail 3 stored. In addition, one is through the sun gear 55 extending axis also in the upper part of the nut 53 rotatably supported.

The sun wheel 55 meshes with the planet wheels 52 of which the embodiment variant of the transmission shown here has three pieces. Of the three planet wheels 52 is the left recognizable graphic halved, the right below the disc with the magnets in half to see and the third planetary gear 52 in 1 not to be seen, because it is cut off graphically.

The planet wheels 52 roll on the ring gear 51 firmly attached to the outer, first guide rail 3 connected is. In 2 is very good to realize that every planetary gear 52 Mounted on a vertical shaft, fixed to the nut 53 is formed.

In the 1 and 2 is good to see that by a rotation of the sun gear 55 also the planet wheels 52 be set in rotation. As they are on the other side also with the ring gear 51 comb, move the planet gears 52 by the mother 53 in rotation. Here is the speed of the mother 53 lower than the speed of the sun gear 55 and that on the mother 53 acting torque in the same ratio reinforced.

As a result, the torque to be transmitted across the skin layer or over the gingival layer is reduced in the same ratio, so that the magnetic field required for this purpose is transmitted via the relatively small upper end face of the first guide rail 3 can be transferred away. This also reduces the size of the holder 7 required electromagnet 61 . 62 and their control by the control processor 92 , Also the peak current load of the power source 91 is reduced accordingly.

There to the movement of the mother 53 Of course, the same amount of energy must be transmitted over each movement cycle as in a direct drive, the service life of a geared motor increases accordingly. With a maximum of four times short operation per day, however, this is irrelevant.

In 1 is understandable that at an increase in the distance between the lower, second anchor plate 2 and the top, first anchor plate 1 the first anchor plate 1 opposite the lower anchor plate 2 lifts up. Accordingly, also raises the outer, first guide rail 1 and thus the drive mechanism arranged at the tip thereof 5 upwards. As a result, with increasing distraction of the callus, the overlying skin layer or gingival layer is raised.

It is clear that the same extent the bracket 7 must be raised so they always the necessary for proper operation, the smallest possible distance to the cap 8th with the permanent magnets underneath 6 having.

When the bracket 7 at their - in the 1 and 2 not drawn - outer ends is mounted on each tooth, then it is clear that a vertical guide must be built on the tooth, along which the holder 7 with increasing distraction is led upwards.

LIST OF REFERENCE NUMBERS

1

first anchor plate

2

second anchor plate

3

first guide rail

4

second guide rail

5

drive mechanism

51

Ring gear, part of the planetary gear id Drive mechanics 5

52

Planet wheel, part of the planetary gear

53

Nut with internal thread, with the first guide rail 3 connected

54

External thread on the second guide rail 4

55

Sun gear, part of the planetary gear id drive mechanics 5

6

Magnet, permanent or electric

61

magnetizable core, part of an electric magnet 6

62

Coil to core 61 wound

7

Mount outside of the callus area for more magnets 6

8th

Cap over the movement space of the magnets 6 on one of the two guide rails 3 . 4

91

energy

92

control processor

93

Signal transmitter, transmits signals to and from the control processor

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

• EP 1489979 [0010]
• EP 1498979 [0011]
• US 2008/0234554 [0015]

Cited non-patent literature

• PB Magnuson: Lengthening shortend bones of the leg by operation. Ivory screws with removable heads as a means of holding the two bones fragments. In SGO: Surgery Gynecolgy and Obstetrics, No. 17, 1913, pages 63-71 [0002]

Claims (23)

Distraction device for callus distraction, consisting of - two anchor plates 1 . 2 , which are arranged approximately parallel to each other or in alignment with each other and - two guide rails 3 . 4 , - each with an anchor plate 1 . 2 are connected and - the approximately perpendicular to the anchor plates 1 . 2 are aligned and - which are mutually movable and - which are arranged parallel to each other and - a drive mechanism 5 showing the movement of the two guide rails 3 . 4 triggers or controlled against each other, characterized in that at least one of the two guide rails 3 . 4 directly or via the drive mechanism 5 with at least one magnet 6 connected via the force to move the guide rails 3 . 4 relative to each other is transferable. Distraction device according to claim 1, characterized in that the first, outer guide rail 3 the second, inner guide rail 4 wraps around against the outer guide rail 3 is telescopically displaceable. Distraction device according to one of the preceding claims, characterized in that both guide rails 3 . 4 by a resiliently latching in a rack pawl as a drive mechanism 5 secured against unintentional displacement, wherein the inclination of the flanks of the teeth on the rack and the orientation of the pawl can be chosen so that the guide rails 3 . 4 only in one direction against each other are displaced. Distraction device according to one of the preceding claims, characterized in that on both guide rails 3 . 4 one permanent magnet each 6 is arranged, its required range of motion by a non-magnetic and tissue-compatible cap 8th is covered and outside of the callus area to be distracted a holder 7 can be placed, the third and a fourth magnet 6 contributes to the first and second permanent magnets 6 each have only a very small distance and the distance between the third and the fourth magnet 6 is changeable by a drive, which also increases the distance between the first and the second permanent magnets 6 on the two guide rails 3 . 4 changes what a displacement of the two guide rails 3 . 4 caused against each other. Distraction device according to claim 4, characterized in that the third and / or the fourth magnet 6 from one coil each 62 which consists of a magnetizable core 61 is wound. Distraction device according to claim 5, characterized in that the third and / or the fourth magnet 6 each move a current pulse, the first and / or the second magnet 6 by at least a quarter of a millimeter or at most a millimeter in the longitudinal direction. Distraction device according to claim 2, characterized in that the two guide rails 3 . 4 secured against a mutual rotation in the longitudinal direction, such. B. by a guide nose or a longitudinal bead in a guide rail 3 . 4 , which in a longitudinal groove in the other guide rail 4 . 3 engages or by a non-circular or by a polygonal profiling of the guide rails 3 . 4 , Distraction device according to claim 7, characterized in that as a drive mechanism 5 A mother 53 - inside the free end of the outer guide rail 3 is rotatable about its longitudinal axis and - is fixed in the longitudinal direction and - has an internal thread, which - to an external thread 54 on the free end of the inner guide rail 4 is complementarily shaped and - the mother 53 mechanically with at least one magnet 6 connected is. Distraction device according to claim 7, characterized in that as a drive mechanism 5 on the free end of the outer guide rail 3 A mother 53 is fixed, whose internal thread to an external thread 54 is shaped complementarily, as a separate threaded piece with the inner guide rail 4 rotatably connected and fixed in the longitudinal direction and the separate threaded piece mechanically with at least one magnet 6 connected is. Distraction device according to claim 8 or 9, characterized in that on the guide rail 3 . 4 with the firmly connected thread at least one magnetizable core 61 is arranged - to the one by electric current durchströmbare coil 62 is wound and - the only a very small air gap to or to the permanent magnets 6 on the rotatably mounted nut or the rotatably mounted threaded piece, which on the core 61 are pivotable over, and - or the cores 61 form the stator of an electric motor and - The one or more permanent magnets 6 form the rotor of the electric motor and - the electric motor by connecting to an electric power source 91 can be set in rotation, so that the two guide rails over the two complementary threads 3 . 4 be moved against each other. Distraction device according to claim 10, characterized in that the electric motor is designed as a stepping motor, which at each current pulse from the energy source 91 is moved by one increment. Distraction device according to one of the preceding claims, characterized in that - the energy source 91 is located subcutaneously directly or in the vicinity of the device and - via an equally subcutaneous control processor 92 and - via a mechanically and electrically connected signal transmitter 93 the control commands for the control processor 92 percutaneously and without contact from a remote control to the control processor 92 are further available. Distraction device according to one of the preceding claims, characterized in that - the energy source 91 is arranged subcutaneously and - is electrically connected to a subcutaneous charger and a likewise subcutaneous transmission coil and - in the immediate vicinity of the skin or the gums of the patient, a second transmission coil is placed, which transmits percutaneous electrical energy to the first transmission coil from the Charger to the power source 91 is given further. Distraction device according to one of the preceding claims, characterized in that between the rotatably mounted nut 53 or the rotatably mounted, separate threaded part and the magnet 6 a transmission, such. B. - a spur gear or - a worm gear or - a planetary gear, consisting of a ring gear 51 and at least one planetary gear 52 and a sun wheel 55 or - a Flexspline or - another gear is arranged. Distraction device according to one of the preceding claims, characterized in that - for the rotation of all magnets 6 required clearance from a cap 8th is covered, - whose material is non-magnetic and biocompatible and - can be overgrown by a layer of skin or gums and - outside the skin or gums a holder 7 can be placed in the electromagnet 6 , each consisting of a magnetizable core 61 and a coil wound around it 62 are attached, - the only a very small distance to the first magnet 6 and - that of a control processor 92 and an energy source 91 phased out, so that a rotating magnetic field is formed on the magnets 6 on a guide rail 3 . 4 acts and thereby sets them in rotation. Distraction device according to one of the preceding claims, characterized in that - the for the rotation of the magnet 6 required clearance from a cap 8th is covered, - whose material is non-magnetic and biocompatible and - can be overgrown by a layer of skin or gums and - outside the skin or gums a holder 7 can be placed, in which a second coupling magnet 6 is rotatably mounted, - the only a very small distance from the first magnet 6 and - at its rotation, the first magnet 6 under the skin or under the gum is rotated by the same angle and - which can be rotated by a handle or an electric drive or another drive in rotation Distraction device according to one of the preceding claims, characterized in that the anchor plates 1 . 2 inserted into an osteomic slot in the jaw of a patient and the guide rails 3 . 4 are aligned approximately parallel to the longitudinal axis of the adjacent teeth. Distraction device according to one of the preceding claims, characterized in that the holder 7 on to the guide rails 3 . 4 is placed on adjacent teeth Distraction device according to one of the preceding claims, characterized in that the electromagnets 6 or the electric drive for the coupling magnet 6 in the holder 7 from a control processor 92 - in which the time and the path of each movement are storable and - from which these values are readable. Distraction device according to one of the preceding claims, characterized in that the electromagnets 6 or the electric drive for the coupling magnet 6 in the holder 7 placed in the mouth of the patient and via a cable, which leads out of the mouth of the patient, are connected to a control unit in which the control processor 92 and the energy source 91 and an operating unit and an evaluation unit for the time and the path of each movement are installed. Distraction device according to one of the preceding claims, characterized in that of the guide rails 3 . 4 at least a portion of the associated attachments is removable and the guide rails 3 . 4 then usable as a pole for a tooth. Method for callus distraction with a distraction device according to one of the preceding claims, characterized in that - in the first step in the bone to be distracted, such. B. an atrophied lower jaw, at least one lateral Osteotomieschlitz is introduced bicortically, which loosens a portion of the bone and a perpendicular extending, auxiliary slot is introduced monocortically and - in the second step in the Osteotomieschlitz the two anchor plates 1 . 2 be pressed and thereby the two guide rails 3 . 4 be fitted into the auxiliary slot and - in the third step during a first resting period of about 5 to 8 days duration callus in the anchor plates 1 . 2 and the guide rails 3 . 4 forms and - in the fourth step by activation of the drive mechanism 5 the two anchor plates 1 . 2 at intervals of at least 6 hours and at most 24 hours apart by at least about 0.25 mm to a maximum of 1.0 mm apart, which increases the callus layer in Osteotomieschlitz accordingly and this step is repeated until the desired callus layer new has formed and - in the fifth step, a rest period of 5 to 8 days is inserted and then the newly formed callus is resilient. A method according to claim 22, characterized in that after the fifth step, the free end of the two guide rails 3 . 4 is cleared and all accessible from there attachments are removed and instead a tooth on the guide rails 3 . 4 is attached.

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