EP1605853A1 - Method and device for detecting a hinge point between two bones - Google Patents
Method and device for detecting a hinge point between two bonesInfo
- Publication number
- EP1605853A1 EP1605853A1 EP04713058A EP04713058A EP1605853A1 EP 1605853 A1 EP1605853 A1 EP 1605853A1 EP 04713058 A EP04713058 A EP 04713058A EP 04713058 A EP04713058 A EP 04713058A EP 1605853 A1 EP1605853 A1 EP 1605853A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- rotation
- orientation
- bone
- scatter
- axes
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 210000000988 bone and bone Anatomy 0.000 title claims abstract description 56
- 238000000034 method Methods 0.000 title claims abstract description 21
- 210000002303 tibia Anatomy 0.000 claims description 23
- 210000000689 upper leg Anatomy 0.000 claims description 23
- 210000000629 knee joint Anatomy 0.000 claims description 9
- 239000006185 dispersion Substances 0.000 abstract description 4
- 238000006073 displacement reaction Methods 0.000 abstract 2
- 210000001503 joint Anatomy 0.000 description 10
- 210000003127 knee Anatomy 0.000 description 6
- 230000005670 electromagnetic radiation Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 238000012935 Averaging Methods 0.000 description 1
- 241001416181 Axis axis Species 0.000 description 1
- 241000124008 Mammalia Species 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- CATMPQFFVNKDEY-AAEUAGOBSA-N gamma-Glu-Trp Chemical compound C1=CC=C2C(C[C@H](NC(=O)CC[C@H](N)C(O)=O)C(O)=O)=CNC2=C1 CATMPQFFVNKDEY-AAEUAGOBSA-N 0.000 description 1
- 210000004394 hip joint Anatomy 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 210000002414 leg Anatomy 0.000 description 1
- 238000012067 mathematical method Methods 0.000 description 1
Classifications
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Definitions
- the invention relates to a method for determining a joint point of two bones connected by a joint which are pivotably connected relative to one another about at least two axes of rotation which are not parallel to one another, in which the two bones are moved relative to one another, the movement of a point of a bone in one Reference system of the other bone records measured values, determines from these measured values for several parts of the path or for one of several successively recorded paths an axis of rotation describing the movement as rotation.
- the position of anatomical articulation points can be determined under certain conditions by moving the bones articulated at these articulation points against each other and by analyzing the movement, for example by means of a navigation system, the position of the articulation point is calculated from the recorded trajectory. This is easily possible, for example, for joints that are equipped as ball joints, as is the case with the hip joint. Such a process is i.a. described in EP 0 969 780 Bl.
- hinge joints or hinge-like joints in the body of mammals are designed so that they can not only be pivoted about a single axis of rotation, but that - at least to a limited extent - pivoting about a second axis of rotation is also possible.
- About the longitudinal axis of the tibia this can be pivoted to a small extent in addition to the normal pivoting movement about the transverse axis, so there are essentially two axes of rotation perpendicular to one another. These axes of rotation together determine a point of articulation for the knee, around which every movement takes place, even if it is formed from the rotations around the two axes of rotation described as a superimposed movement.
- an articulation point can be determined, but it is necessary to actually pivot the two bones against each other about these two axes of rotation in order to be able to determine this articulation point.
- a pivoting movement alone around one of the two axes of rotation would not be sufficient, since the determination of an axis of rotation alone does not yet determine a pivot point along this axis of rotation.
- This object is achieved according to the invention in a method of the type described at the outset by calculating the scatter in the orientation for the differently oriented axes of rotation determined in this way and only calculating an articulation point from the differently oriented axes of rotation if the scatter in the orientation of the axes of rotation unites exceeds a certain value.
- the invention is thus based on the knowledge that all actually determined axes of rotation are formed by superimposing the joint's own axes of rotation, in the case of the knee, for example, as a superposition of the flexion axis of the knee on the one hand and the tibial longitudinal axis as the second axis of rotation on the other.
- the spread of this orientation is a measure of how strongly the shares of these two main axes of rotation are represented in the differently oriented axes of rotation. If the joint is only moved so that all axes of rotation are substantially parallel, then it is impossible to determine a joint point. The more the differently oriented axes of rotation differ in their orientation, the more precisely they define the point of articulation sought through their intersection.
- the momentary orientation of one bone in the reference system of the other bone is determined during a movement of the two bones relative to one another in different relative positions, and a momentary axis of rotation is calculated for this momentary orientation, which is a rotation of the bone from an assumed reference orientation corresponds to this momentary orientation, and that the scatter in the orientation is determined by the scatter of the momentary axes of rotation.
- the position of the one bone relative to the other is tracked using a navigation system and a marking element is attached to one of the bones. If you hold the other bone firmly during the relative movement of the two bones, the trajectory curve of one bone relative to the other can then easily be recorded.
- the determination of the other bone can be omitted if one also fixes a marking element on the other bone.
- the method can be carried out particularly advantageously on the knee joint by moving the tibia relative to the femur.
- the invention further relates to a device for carrying out the method described with a navigation system, at least one marking element of the navigation system which can be fixed on the bone and with one of the measured values recorded for a part of the path or for one of several successively recorded paths Data processing system determining movement as rotation describing axis of rotation.
- the data processing system calculate the scatter in the orientation for the differently oriented axes of rotation determined in this way and only then from the differently oriented axes of rotation calculates a pivot point if the scatter in the orientation of the axes of rotation exceeds a certain value.
- the data processing system determines the instantaneous orientation of one bone in the reference system of the other bone during a movement of the two bones relative to one another in different relative positions, and calculates a momentary axis of rotation for this momentary orientation, which rotates the bone from an assumed reference orientation into it Current orientation corresponds, and that the data processing system determines the scatter in the orientation by the scatter of the current axes of rotation.
- the data processing system is assigned a display on which the scatter of the orientation of the movement carried out is shown.
- the data processing system blocks the determination of an articulation point as long as the specific value of the scatter of the orientation has not been reached.
- the navigation system can be assigned a marking element on one and on the other bone.
- Figure 1 an overall view of a device for determining the knee joint point of a patient with a navigation system and a data processing system;
- Figure 2 is a schematic representation of the main axes of rotation of a tibia relative to a femur;
- Figure 3 is a schematic representation of the knee joint with a bundle of differently oriented knee pivot axes
- Figure 4 a schematic representation of the inclusion of different
- a patient 2 is lying on an operating table 1, with whom the joint point of the knee joint 3 is to be determined.
- a marking element 6 or 7 is fixed on both the femur 4 and the tibia 5, which interacts in a manner known per se with a navigation system 8 set up in the operating room.
- the marking elements 6, 7 each carry three reference bodies 9 at a distance from one another, which either emit electromagnetic radiation themselves or reflect electromagnetic radiation incident on them, for example infrared radiation. This radiation is received by three receivers 10 of the navigation system 8 arranged at a distance from one another, and in this way the exact position and orientation of the marking elements 6, 7 in the room can be determined by the navigation system.
- Data sets corresponding to the respective position are fed by the navigation system 8 to a data processing system 11, which can display these data and data derived therefrom on a display 12.
- FIG. 2 shows which movements the tibia 5 can perform relative to the femur 4.
- This movement is essentially a hinge-like pivoting movement about a flexion axis 13 running transversely to the longitudinal direction of the femur and tibia and next to it a rotation about the longitudinal axis 14 of the tibia 5.
- This rotation about the longitudinal axis 14 is limited and only possible over a relatively small angular range
- pivoting about the flexion axis 13 can sweep an angle of well over 90 °.
- the point of articulation 15 of the knee joint 3 can be determined from the intersection of the flexion axis 13 and the longitudinal axis 14. If the two axes do not intersect exactly, but only run very close together, can this point can also be defined as a point between the two axes and as close as possible to this point.
- the tibia 5 is moved relative to the femur 4 in such a way that this movement does not only consist of a pure bending of the knee, but also a part of a rotary movement about the Includes longitudinal axis 14, ie The two bones move as irregularly as possible against one another, the practitioner not having to pay attention to how this movement proceeds.
- the data processing system can use the movement of the marking element 6 on the femur 4 and the marking element 7 on the tibia 5 to perform the relative movement Determine the tibia and femur and thus the respective position of the marking element 7 and thus the tibia 5 in a femur's own reference system.
- the rotation axes of this movement can be determined from the movement curves of the marking element 7 in the femur's own reference system using algorithms known per se, i.e. averaged rotation axes are determined from the trajectory curves, for example by averaging different positions and orientations of the marking element 7, which counteract the movements of the tibia in successive movements the femur will usually be different depending on how the tibia has been moved relative to the femur.
- these axes of rotation will normally not deviate too much from the flexion axis 13, since the movement around this flexion axis axis can cover a much larger angular range than the rotation about the longitudinal axis 14.
- the axes of rotation determined in this way then lie, for example, in a double cone 16, the longitudinal axis of which coincides with the flexion axis and the tip of which marks the hinge point 15 sought.
- This articulation point 15 can only be determined very imprecisely if the opening angle of the double cone 16 is very small, that is to say if the deviation of the axes of rotation determined in this way is small from one another, if the angle of the double cone 16 becomes larger, on the other hand, a more precise determination of the exact
- the position of the hinge point 15 ensures that the larger angle of the double cone 16 corresponds to a greater dispersion of the orientation of the axes of rotation determined in this way.
- the data processing system 11 determines the deviation or scatter of the orientation values from one another from the individual orientations of the axes of rotation and compares them with a predetermined reference value. If the scatter lies below this reference value, the measured values are not used to calculate a joint point, since the scatter is then too small in accordance with the angle of the double cone 16 and only imprecise information about the joint point 15 can be obtained. The articulation point is only calculated in the manner described when the predetermined value of the scatter is exceeded.
- the value of the scatter can be shown on the display 12 so that it can be read at any time whether the movement of the tibia relative to the femur has taken the two pivoting options sufficiently into account, that is, was irregular enough. If the scatter threshold has not yet been reached, the practitioner merely has to ensure that the following movements of the tibia relative to the femur deviate as much as possible from a pure pivoting movement in a single plane.
- the orientation of the marking element 7 of the tibia 5 in the femur's own reference system is determined in different positions during the course of movement, this is symbolized in FIG. 4 by a large number of axis crosses, each of which indicates the position of this marking element 7, in relation to a reference orientation R, which can be calculated, for example, from the mean of all individual orientations.
- the data processing system For each position of the marking element 7 during the movement sequence, the data processing system now calculates a momentary axis of rotation, which is selected such that the axis cross corresponding to a certain position passes into the axis cross of the reference system solely by rotation about this momentary axis of rotation. In other words, it is determined about which axis the marking element 7 has to be rotated in order to reach the reference position corresponding to the axis cross R. This is carried out in this way for all positions of the marking element 7 determined along the path curve and leads to a number of differently oriented instantaneous axes of rotation.
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Abstract
Description
WE_^F C-_ _^EM U N D TOD&IOCHTyra© ZTO BESTIM M (U N© EIN ES (SEtLEϊWIPy N C€ ES TOM ZWEI C€MOCM EMWE_ ^ F C-_ _ ^ EM UND TOD & IOCHTyra © ZTO BESTIM M ( UN © EIN ES ( SEtLEϊWIPy NC € ES TOM TWO C € MOCM EM
Die Erfindung betrifft ein Verfahren zur Bestimmung eines Gelenkpunktes von zwei durch ein Gelenk verbundenen Knochen, die um mindestens zwei nicht zueinander parallele Drehachsen relativ zueinander verschwenkbar verbunden sind, bei dem man die beiden Knochen relativ zueinander bewegt, dabei die Bewegung eines Punktes eines Knochens in einem Referenzsystem des anderen Knochens beschreibende Meßwerte aufnimmt, aus diesen Meßwerten für mehrere Teile der Bahn oder für jeweils eine von mehreren nacheinander aufgenommenen Bahnen eine die Bewegung als Rotation beschreibende Drehachse bestimmt.The invention relates to a method for determining a joint point of two bones connected by a joint which are pivotably connected relative to one another about at least two axes of rotation which are not parallel to one another, in which the two bones are moved relative to one another, the movement of a point of a bone in one Reference system of the other bone records measured values, determines from these measured values for several parts of the path or for one of several successively recorded paths an axis of rotation describing the movement as rotation.
Die Lage von anatomischen Gelenkpunkten kann unter bestimmten Voraussetzungen dadurch bestimmt werden, daß die an diesen Gelenkpunkten gelenkig miteinander verbundenen Knochen gegeneinander bewegt werden und daß durch die Analyse der Bewegung, beispielsweise mittels eines Navigationssystems, die Lage des Gelenkpunktes aus den aufgenommenen Bahnkurven berechnet wird. Dies ist beispielsweise problemlos möglich bei Gelenken, die als Kugelgelenk ausgestattet sind, wie dies beim Hüftgelenk der Fall ist. Ein solches Verfahren ist u.a. beschrieben in der EP 0 969 780 Bl.The position of anatomical articulation points can be determined under certain conditions by moving the bones articulated at these articulation points against each other and by analyzing the movement, for example by means of a navigation system, the position of the articulation point is calculated from the recorded trajectory. This is easily possible, for example, for joints that are equipped as ball joints, as is the case with the hip joint. Such a process is i.a. described in EP 0 969 780 Bl.
Schwieriger ist jedoch die exakte Bestimmung eines Gelenkpunktes für solche Gelenke durchführbar, die nicht als reine Kugelgelenke ausgebildet sind, sondern die im wesentlichen Scharniergelenke oder scharnierähnliche Gelenke sind. Wenn ein Gelenk ein reines Scharniergelenk ist, existiert eine feste Dreh- achse, jedoch kein zentraler Gelenkpunkt. Bei derartigen Gelenken macht es also keinen Sinn, einen solchen Gelenkpunkt zu bestimmen.However, it is more difficult to determine the exact joint point for joints that are not designed as pure ball joints, but that are essentially hinge joints or hinge-like joints. If a joint is a pure hinge joint, there is a fixed rotation axis, but not a central hinge point. With such joints, it makes no sense to determine such a joint point.
Die meisten Scharniergelenke oder scharnierähnlichen Gelenke im Körper von Säugetieren sind jedoch so ausgebildet, daß sie nicht nur um eine einzige Drehachse verschwenkt werden können, sondern daß - zumindest in begrenztem Umfange - auch eine Verschwenkung um eine zweite Drehachse möglich ist. Dies gilt beispielsweise beim Kniegelenk. Um die Längsachse der Tibia kann diese in geringem Umfange neben der normalen Verschwenkbewegung um die Querachse verschwenkt werden, es existieren also im wesentlichen zwei senkrecht aufeinanderstehende Drehachsen. Diese Drehachsen bestimmen gemeinsam einen Gelenkpunkt für das Knie, um den jede Bewegung erfolgt, auch wenn sie aus den Drehungen um die beiden beschriebenen Drehachsen als überlagerte Bewegung gebildet wird. In diesen Fällen kann also ein Gelenkpunkt bestimmt werden, allerdings ist es notwendig, die beiden Knochen auch tatsächlich um diese beiden Drehachsen gegeneinander zu verschwenken, um diesen Gelenkpunkt festlegen zu können. Eine Verschwenkbewegung allein um eine der beiden Drehachsen würde nicht ausreichen, da mit der Bestimmung einer Drehachse allein noch kein Gelenkpunkt längs dieser Drehachse festgelegt wird.Most hinge joints or hinge-like joints in the body of mammals are designed so that they can not only be pivoted about a single axis of rotation, but that - at least to a limited extent - pivoting about a second axis of rotation is also possible. This applies, for example, to the knee joint. About the longitudinal axis of the tibia this can be pivoted to a small extent in addition to the normal pivoting movement about the transverse axis, so there are essentially two axes of rotation perpendicular to one another. These axes of rotation together determine a point of articulation for the knee, around which every movement takes place, even if it is formed from the rotations around the two axes of rotation described as a superimposed movement. In these cases, an articulation point can be determined, but it is necessary to actually pivot the two bones against each other about these two axes of rotation in order to be able to determine this articulation point. A pivoting movement alone around one of the two axes of rotation would not be sufficient, since the determination of an axis of rotation alone does not yet determine a pivot point along this axis of rotation.
Es ist Aufgabe der Erfindung, ein gattungsgemäßes Verfahren so auszuführen, daß bei der Bewegung von zwei Knochen ein Gelenkpunkt mit der gewünschten Genauigkeit bestimmt werden kann. Diese Aufgabe wird bei einem Verfahren der eingangs beschriebenen Art erfindungsgemäß dadurch gelöst, daß man für die derart bestimmten unterschiedlich orientierten Drehachsen deren Streuung in der Orientierung berechnet und aus den unterschiedlich orientierten Drehachsen nur dann einen Gelenkpunkt berechnet, wenn die Streuung in der Orientierung der Drehachsen einen bestimmten Wert übersteigt.It is an object of the invention to carry out a generic method such that a joint point can be determined with the desired accuracy when moving two bones. This object is achieved according to the invention in a method of the type described at the outset by calculating the scatter in the orientation for the differently oriented axes of rotation determined in this way and only calculating an articulation point from the differently oriented axes of rotation if the scatter in the orientation of the axes of rotation unites exceeds a certain value.
Die Erfindung geht somit aus von der Erkenntnis, daß alle tatsächlich bestimmten Drehachsen durch Überlagerung der gelenkeigenen Drehachsen gebildet werden, beim Knie also beispielsweise als Überlagerung der Flexionsachse des Knies einerseits und der Tibialängsachse als zweiter Drehachse andererseits. Die Streuung dieser Orientierung ist ein Maß dafür, wie stark in den unterschiedlich orientierten Drehachsen die Anteile dieser beiden Hauptdrehachsen vertreten sind. Wenn das Gelenk nur so bewegt wird, daß alle Drehachsen im wesentlichen parallel sind, dann ist es unmöglich, einen Gelenkpunkt zu bestimmen. Je stärker die unterschiedlich orientierten Drehachsen in ihrer Orientierung voneinander abweichen, desto genauer definieren sie durch ihren Schnittpunkt den gesuchten Gelenkpunkt.The invention is thus based on the knowledge that all actually determined axes of rotation are formed by superimposing the joint's own axes of rotation, in the case of the knee, for example, as a superposition of the flexion axis of the knee on the one hand and the tibial longitudinal axis as the second axis of rotation on the other. The spread of this orientation is a measure of how strongly the shares of these two main axes of rotation are represented in the differently oriented axes of rotation. If the joint is only moved so that all axes of rotation are substantially parallel, then it is impossible to determine a joint point. The more the differently oriented axes of rotation differ in their orientation, the more precisely they define the point of articulation sought through their intersection.
Durch Feststellung der Streuung können somit Messungen ausgeschieden werden, bei denen de Drehachsen sich in ihrer Orientierung zu wenig voneinander unterscheiden, bei denen also eine genaue Lagebestimmung des Gelenkpunktes nicht möglich ist. Umgekehrt werden dann, wenn die unterschiedlichen Orientierungen der Drehachsen genügend voneinander abweichen und damit eine große Streuung aufweisen, zuverlässige Werte für den Gelenkpunkt errechnet. Bei der Aufnahme der Bewegung ist es also nicht notwendig, daß man darauf achtet, die Bewegung der beiden Knochen genau um die beiden Hauptachsen vorzunehmen, sondern es genügt, wenn die Streuung der Orientierung der aufgenommenen Drehachsen groß genug ist, um sicher zu sein, daß dann genügend Anteile beider Hauptdrehachsen berücksichtigt worden sind. Man kann also beispielsweise die Tibia gegenüber dem Femur in beliebiger Weise bewegen, wobei man die vom Knie zur Verfügung gestellten Freiheitsgrade ausnützt, und sobald sich dabei eine ausreichende Streuung ergibt, ist man sicher, eine zuverlässige Gelenkpunktbestimmung durchführen zu können.By ascertaining the scatter, measurements can thus be eliminated in which the axes of rotation differ too little from one another in their orientation, and in which therefore it is not possible to determine the position of the articulation point precisely. Conversely, if the different orientations of the axes of rotation differ sufficiently from one another and thus have a large spread, reliable values for the articulation point are calculated. When recording the movement, it is therefore not necessary to make sure that the two bones move exactly around the two main axes, but it is sufficient if the dispersion of the orientation of the recorded axes of rotation is large enough to be sure that then sufficient shares of both main axes of rotation have been taken into account. For example, one can move the tibia in relation to the femur in any way, making use of the degrees of freedom provided by the knee, and as soon as there is sufficient scatter, it is certain to be able to reliably determine the joint point.
Grundsätzlich können die verschiedensten Verfahren verwendet werden, um aus den Bahnkurven der beiden gegeneinander bewegten Knochen unterschiedlich orientierte Drehachsen zu bestimmen.In principle, a wide variety of methods can be used to determine differently oriented axes of rotation from the trajectories of the two bones moved against each other.
Bei einem besonders bevorzugten Verfahren wird vorgesehen, daß man während einer Bewegung der beiden Knochen relativ zueinander in verschiedenen Relativpositionen die Momentanorientierung eines Knochens im Referenzsystem des anderen Knochens bestimmt und für diese Momentanorientierung eine Momentan-Drehachse berechnet, die einer Drehung des Knochens aus einer angenommenen Referenzorientierung in diese Momentanorientierung entspricht, und daß man die Streuung in der Orientierung durch die Streuung der Momentan-Drehachsen bestimmt.In a particularly preferred method, it is provided that the momentary orientation of one bone in the reference system of the other bone is determined during a movement of the two bones relative to one another in different relative positions, and a momentary axis of rotation is calculated for this momentary orientation, which is a rotation of the bone from an assumed reference orientation corresponds to this momentary orientation, and that the scatter in the orientation is determined by the scatter of the momentary axes of rotation.
Es ist vorteilhaft, wenn man die Streuung der Orientierung der durchgeführten Bewegung auf einer Anzeige darstellt. Man kann dann an dieser Anzeige sofort erkennen, ob die Streuung der Orientierung der Drehachsen ausreichend groß ist, sollte das nicht der Fall sein, kann man durch Änderung des Bewegungsablaufes dafür sorgen, daß die Streuung den gewünschten Wert erreicht.It is advantageous to show the scatter of the orientation of the movement carried out on a display. From this display you can immediately see whether the scatter of the orientation of the axes of rotation is sufficiently large If this is not the case, you can make sure that the scatter reaches the desired value by changing the sequence of movements.
Günstig ist es, wenn man die Bestimmung eines Gelenkpunktes blockiert, solange der bestimmte Wert der Streuung der Orientierung nicht erreicht ist. Man ist auf diese Weise sicher, keine Fehlbestimmung des Gelenkpunktes durchzuführen.It is expedient to block the determination of a joint point as long as the specific value of the scatter of the orientation has not been reached. In this way, one is certain not to make any incorrect determination of the joint point.
Vorteilhaft ist es, wenn man zur Bestimmung der Bewegung eines Knochens in einem Referenzsystem des anderen Knochens die Lage des einen Knochens relativ zum anderen über ein Navigationssystem verfolgt und dazu an dem einen Knochen ein Markierelement festlegt. Hält man den anderen Knochen bei der Relativbewegung der beiden Knochen fest, läßt sich dann die Bahnkurve des einen Knochens gegenüber dem anderen ohne weiteres aufnehmen.It is advantageous if, in order to determine the movement of a bone in a reference system of the other bone, the position of the one bone relative to the other is tracked using a navigation system and a marking element is attached to one of the bones. If you hold the other bone firmly during the relative movement of the two bones, the trajectory curve of one bone relative to the other can then easily be recorded.
Die Festlegung des anderen Knochens kann entfallen, wenn man auch an dem anderen Knochen ein Markierelement festlegt.The determination of the other bone can be omitted if one also fixes a marking element on the other bone.
Besonders vorteilhaft läßt sich das Verfahren am Kniegelenk durchführen, indem man die Tibia relativ zum Femur bewegt.The method can be carried out particularly advantageously on the knee joint by moving the tibia relative to the femur.
Die Erfindung betrifft weiterhin eine Vorrichtung zur Durchführung des beschriebenen Verfahrens mit einem Navigationssystem, mindestens einem an dem einen Knochen festlegbaren Markierelement des Navigationssystems und mit einer aus den aufgenommenen Meßwerten für einen Teil der Bahn oder für jeweils eine von mehreren nacheinander aufgenommenen Bahnen eine die Bewegung als Rotation beschreibende Drehachse bestimmenden Datenverarbeitungsanlage.The invention further relates to a device for carrying out the method described with a navigation system, at least one marking element of the navigation system which can be fixed on the bone and with one of the measured values recorded for a part of the path or for one of several successively recorded paths Data processing system determining movement as rotation describing axis of rotation.
Um mit einer solchen Vorrichtung zuverlässig einen Gelenkpunkt auch bei Gelenken bestimmen zu können, die nicht als Kugelgelenk ausgebildet sind, wird vorgeschlagen, daß die Datenverarbeitungsanlage für die derart bestimmten, unterschiedlich orientierten Drehachsen deren Streuung in der Orientierung berechnet und aus den unterschiedlich orientierten Drehachsen nur dann einen Gelenkpunkt berechnet, wenn die Streuung in der Orientierung der Drehachsen einen bestimmten Wert übersteigt.In order to be able to reliably determine an articulation point with such a device even in joints that are not designed as a ball joint, it is proposed that the data processing system calculate the scatter in the orientation for the differently oriented axes of rotation determined in this way and only then from the differently oriented axes of rotation calculates a pivot point if the scatter in the orientation of the axes of rotation exceeds a certain value.
Insbesondere kann vorgesehen sein, daß die Datenverarbeitungsanlage während einer Bewegung der beiden Knochen relativ zueinander in verschiedenen Relativpositionen die Momentanorientierung eines Knochens im Referenzsystem des anderen Knochens bestimmt und für diese Momentanorientierung eine Momentan-Drehachse berechnet, die einer Drehung des Knochens aus einer angenommenen Referenzorientierung in diese Momentanorientierung entspricht, und daß die Datenverarbeitungsanlage die Streuung in der Orientierung durch die Streuung der Momentan-Drehachsen bestimmt.In particular, it can be provided that the data processing system determines the instantaneous orientation of one bone in the reference system of the other bone during a movement of the two bones relative to one another in different relative positions, and calculates a momentary axis of rotation for this momentary orientation, which rotates the bone from an assumed reference orientation into it Current orientation corresponds, and that the data processing system determines the scatter in the orientation by the scatter of the current axes of rotation.
Es ist günstig, wenn der Datenverarbeitungsanlage eine Anzeige zugeordnet ist, auf der die Streuung der Orientierung der durchgeführten Bewegung dargestellt wird.It is advantageous if the data processing system is assigned a display on which the scatter of the orientation of the movement carried out is shown.
Gemäß einer bevorzugten Ausführungsform ist vorgesehen, daß die Datenverarbeitungsanlage die Bestimmung eines Gelenkpunktes blockiert, solange der bestimmte Wert der Streuung der Orientierung nicht erreicht ist. Dem Navigationssystem kann je ein Markierelement an dem einen und an dem anderen Knochen zugeordnet sein.According to a preferred embodiment, it is provided that the data processing system blocks the determination of an articulation point as long as the specific value of the scatter of the orientation has not been reached. The navigation system can be assigned a marking element on one and on the other bone.
Die nachfolgende Beschreibung bevorzugter Ausführungsformen der Erfindung dient im Zusammenhang mit der Zeichnung der näheren Erläuterung. Es zeigen:The following description of preferred embodiments of the invention serves in conjunction with the drawing for a more detailed explanation. Show it:
Figur 1: eine Gesamtansicht einer Vorrichtung zur Bestimmung des Kniegelenkpunktes eines Patienten mit einem Navigationssystem und einer Datenverarbeitungsanlage;Figure 1: an overall view of a device for determining the knee joint point of a patient with a navigation system and a data processing system;
Figur 2: eine schematische Darstellung der Hauptdrehachsen einer Tibia relativ zu einem Femur;Figure 2 is a schematic representation of the main axes of rotation of a tibia relative to a femur;
Figur 3: eine schematische Darstellung des Kniegelenks mit einem Bündel von unterschiedlich orientierten Kniegelenk-Schwenkachsen undFigure 3 is a schematic representation of the knee joint with a bundle of differently oriented knee pivot axes and
Figur 4: eine schematische Darstellung der Aufnahme unterschiedlicherFigure 4: a schematic representation of the inclusion of different
Orientierungen der gegeneinander verschwenkten Knochen und der daraus ableitbaren Lage einer Drehachse.Orientations of the pivoted bones and the position of an axis of rotation that can be derived from them.
Auf einem Operationstisch 1 liegt ein Patient 2, bei dem der Gelenkpunkt des Kniegelenks 3 bestimmt werden soll. In der Zeichnung sind der Femur 4 und die Tibia 5 dargestellt, die über das Kniegelenk 3 gelenkig miteinander verbunden sind. Sowohl am Femur 4 als auch an der Tibia 5 ist je ein Markierelement 6 bzw. 7 festgelegt, das in an sich bekannter Weise mit einem im Operationssaal aufgestellten Navigationssystem 8 zusammenwirkt. Die Markierelemente 6, 7 tragen jeweils im Abstand zueinander drei Referenzkörper 9, die entweder selbst eine elektromagnetische Strahlung aussenden oder eine auf sie auffallende elektromagnetische Strahlung reflektieren, beispielsweise eine Infrarotstrahlung. Diese Strahlung wird von drei im Abstand zueinander angeordneten Empfängern 10 des Navigationssystems 8 aufgenommen, und auf diese Weise kann die genaue Position und Orientierung der Markierelemente 6, 7 im Raum vom Navigationssystem festgelegt werden. Der jeweiligen Lage entsprechende Datensätze werden von dem Navigationssystem 8 einer Datenverarbeitungsanlage 11 zugeführt, die diese Daten und daraus abgeleitete Daten auf einer Anzeige 12 darstellen kann.A patient 2 is lying on an operating table 1, with whom the joint point of the knee joint 3 is to be determined. In the drawing, the femur 4 and shown the tibia 5, which are articulated to one another via the knee joint 3. A marking element 6 or 7 is fixed on both the femur 4 and the tibia 5, which interacts in a manner known per se with a navigation system 8 set up in the operating room. The marking elements 6, 7 each carry three reference bodies 9 at a distance from one another, which either emit electromagnetic radiation themselves or reflect electromagnetic radiation incident on them, for example infrared radiation. This radiation is received by three receivers 10 of the navigation system 8 arranged at a distance from one another, and in this way the exact position and orientation of the marking elements 6, 7 in the room can be determined by the navigation system. Data sets corresponding to the respective position are fed by the navigation system 8 to a data processing system 11, which can display these data and data derived therefrom on a display 12.
In Figur 2 ist dargestellt, welche Bewegungen die Tibia 5 relativ zum Femur 4 ausführen kann. Diese Bewegung ist im wesentlichen eine scharnierähnliche Schwenkbewegung um eine quer zur Längsrichtung von Femur und Tibia verlaufende Beugeachse 13 und daneben eine Drehung um die Längsachse 14 der Tibia 5. Diese Drehung um die Längsachse 14 ist begrenzt und nur über einen relativ geringen Winkelbereich möglich, die Verschwenkung um die Beugeachse 13 dagegen kann einen Winkel von deutlich über 90° überstreichen.FIG. 2 shows which movements the tibia 5 can perform relative to the femur 4. This movement is essentially a hinge-like pivoting movement about a flexion axis 13 running transversely to the longitudinal direction of the femur and tibia and next to it a rotation about the longitudinal axis 14 of the tibia 5. This rotation about the longitudinal axis 14 is limited and only possible over a relatively small angular range In contrast, pivoting about the flexion axis 13 can sweep an angle of well over 90 °.
Aus dem Schnittpunkt der Beugeachse 13 und der Längsachse 14 läßt sich der Gelenkpunkt 15 des Kniegelenks 3 bestimmen. Wenn sich die beiden Achsen nicht genau schneiden, sondern nur sehr dicht aneinander vorbeilaufen, kann dieser Punkt auch als ein zwischen den beiden Achsen und möglichst dicht an diesen liegender Punkt definiert werden.The point of articulation 15 of the knee joint 3 can be determined from the intersection of the flexion axis 13 and the longitudinal axis 14. If the two axes do not intersect exactly, but only run very close together, can this point can also be defined as a point between the two axes and as close as possible to this point.
Um die Lage dieses Gelenkpunktes 15 allein aus der Bewegung der Tibia relativ zum Femur bestimmen zu können, wird die Tibia 5 relativ zum Femur 4 so bewegt, daß diese Bewegung nicht nur aus einer reinen Beugung des Knies besteht, sondern auch Anteile einer Drehbewegung um die Längsachse 14 enthält, d.h. es wird eine möglichst unregelmäßige Bewegung der beiden Knochen gegeneinander durchgeführt, wobei der Behandler nicht darauf achten muß, wie diese Bewegung genau abläuft.In order to be able to determine the position of this articulation point 15 solely from the movement of the tibia relative to the femur, the tibia 5 is moved relative to the femur 4 in such a way that this movement does not only consist of a pure bending of the knee, but also a part of a rotary movement about the Includes longitudinal axis 14, ie The two bones move as irregularly as possible against one another, the practitioner not having to pay attention to how this movement proceeds.
Da sowohl am Femur als auch an der Tibia jeweils ein Markierelement 6, 7 festgelegt ist, kann sich dabei auch der Femur 4 beliebig bewegen, die Datenverarbeitungsanlage kann aus der Bewegung des Markierelementes 6 am Femur 4 und des Markierelementes 7 an der Tibia 5 die Relativbewegung von Tibia und Femur bestimmen und damit die jeweilige Lage des Markierelementes 7 und damit der Tibia 5 in einem femureigenen Referenzsystem.Since a marking element 6, 7 is fixed to both the femur and the tibia, the femur 4 can also move as desired, the data processing system can use the movement of the marking element 6 on the femur 4 and the marking element 7 on the tibia 5 to perform the relative movement Determine the tibia and femur and thus the respective position of the marking element 7 and thus the tibia 5 in a femur's own reference system.
Aus den Bewegungskurven des Markierelementes 7 im femureigenen Referenzsystem lassen sich mit an sich bekannten Algorithmen die Drehachsen dieser Bewegung bestimmen, es werden also aus den Bahnkurven beispielsweise durch Mittelung verschiedener Positionen und Orientierungen des Markierelementes 7 gemittelte Drehachsen bestimmt, die bei nacheinander erfolgenden Bewegungen der Tibia gegenüber dem Femur in der Regel verschieden sein werden, je nachdem wie die Tibia relativ zum Femur bewegt worden ist. Allerdings werden beim Kniegelenk diese Drehachsen normalerweise nicht allzusehr von der Beugeachse 13 abweichen, da die Bewegung um diese Beuge- achse einen wesentlich größeren Winkelbereich überstreichen kann als die Rotation um die Längsachse 14. Die auf diese Weise ermittelten Drehachsen liegen dann beispielsweise in einem Doppelkonus 16, dessen Längsachse mit der Beugeachse zusammenfällt und dessen Spitze den gesuchten Gelenkpunkt 15 markiert.The rotation axes of this movement can be determined from the movement curves of the marking element 7 in the femur's own reference system using algorithms known per se, i.e. averaged rotation axes are determined from the trajectory curves, for example by averaging different positions and orientations of the marking element 7, which counteract the movements of the tibia in successive movements the femur will usually be different depending on how the tibia has been moved relative to the femur. However, in the knee joint, these axes of rotation will normally not deviate too much from the flexion axis 13, since the movement around this flexion axis axis can cover a much larger angular range than the rotation about the longitudinal axis 14. The axes of rotation determined in this way then lie, for example, in a double cone 16, the longitudinal axis of which coincides with the flexion axis and the tip of which marks the hinge point 15 sought.
Dieser Gelenkpunkt 15 kann nur sehr ungenau bestimmt werden, wenn der Öffnungswinkel des Doppelkonus 16 sehr klein ist, wenn also die Abweichung der auf diese Weise bestimmten Drehachsen voneinander gering ist, wenn der Winkel des Doppelkonus 16 dagegen größer wird, ist eine genauere Bestimmung der genauen Lage des Gelenkpunktes 15 gewährleistet, der größere Winkel des Doppelkonus 16 entspricht einer größeren Streuung der Orientierung der auf diese Weise bestimmten Drehachsen.This articulation point 15 can only be determined very imprecisely if the opening angle of the double cone 16 is very small, that is to say if the deviation of the axes of rotation determined in this way is small from one another, if the angle of the double cone 16 becomes larger, on the other hand, a more precise determination of the exact The position of the hinge point 15 ensures that the larger angle of the double cone 16 corresponds to a greater dispersion of the orientation of the axes of rotation determined in this way.
Die Datenverarbeitungsanlage 11 ermittelt aus den einzelnen Orientierungen der Drehachsen die Abweichung oder Streuung der Orientierungswerte voneinander und vergleicht diese mit einem vorgegebenen Referenzwert. Liegt die Streuung unterhalb dieses Referenzwertes, werden die gemessenen Werte nicht zur Berechnung eines Gelenkpunktes verwendet, da dann die Streuung entsprechend dem Winkel des Doppelkonus 16 zu gering ist und nur ungenaue Angaben über den Gelenkpunkt 15 zu erhalten sind. Erst beim Überschreiten des vorgegebenen Wertes der Streuung wird der Gelenkpunkt in der beschriebenen Weise berechnet.The data processing system 11 determines the deviation or scatter of the orientation values from one another from the individual orientations of the axes of rotation and compares them with a predetermined reference value. If the scatter lies below this reference value, the measured values are not used to calculate a joint point, since the scatter is then too small in accordance with the angle of the double cone 16 and only imprecise information about the joint point 15 can be obtained. The articulation point is only calculated in the manner described when the predetermined value of the scatter is exceeded.
Der Wert der Streuung kann auf der Anzeige 12 dargestellt werden, so daß jederzeit ablesbar ist, ob die Bewegung der Tibia relativ zum Femur die beiden Verschwenkmöglichkeiten in ausreichendem Maße berücksichtigt hat, also ge- nügend unregelmäßig war. Wenn der Streuschwellwert noch nicht erreicht ist, muß der Behandler lediglich dafür sorgen, daß bei folgenden Bewegungen der Tibia relativ zum Femur diese Bewegung möglichst stark abweicht von einer reinen Schwenkbewegung in einer einzigen Ebene.The value of the scatter can be shown on the display 12 so that it can be read at any time whether the movement of the tibia relative to the femur has taken the two pivoting options sufficiently into account, that is, was irregular enough. If the scatter threshold has not yet been reached, the practitioner merely has to ensure that the following movements of the tibia relative to the femur deviate as much as possible from a pure pivoting movement in a single plane.
Während es grundsätzlich möglich ist, die unterschiedlich orientieren Drehachsen durch aufeinanderfolgende Bewegungsabläufe der Tibia relativ zum Femur zu messen, kann bei einem anderen Verfahren vorgesehen sein, daß während eines einzigen Bewegungsablaufes unterschiedliche Komponenten dieser Bewegung analysiert und zur Berechnung einer größeren Anzahl von Momentan-Drehachsen benutzt werden.While it is fundamentally possible to measure the differently oriented axes of rotation by successive movement sequences of the tibia relative to the femur, another method can provide that different components of this movement are analyzed during a single movement sequence and used to calculate a larger number of momentary rotation axes become.
Dazu wird in unterschiedlichen Positionen während des Bewegungsablaufes jeweils die Orientierung des Markierelementes 7 der Tibia 5 im femureigenen Referenzsystem bestimmt, dies ist in Figur 4 durch eine Vielzahl von Achsenkreuzen symbolisiert, die jeweils die Lage dieses Markierelementes 7 angeben, und zwar in Bezug auf eine Referenzorientierung R, die beispielsweise aus dem Mittelwert aller Einzelorientierungen berechnet werden kann.For this purpose, the orientation of the marking element 7 of the tibia 5 in the femur's own reference system is determined in different positions during the course of movement, this is symbolized in FIG. 4 by a large number of axis crosses, each of which indicates the position of this marking element 7, in relation to a reference orientation R, which can be calculated, for example, from the mean of all individual orientations.
Für jede Stellung des Markierelementes 7 während des Bewegungsablaufes berechnet nun die Datenverarbeitungsanlage eine Momentan-Drehachse, die so gewählt ist, daß allein durch eine Drehung um diese Momentan-Drehachse das einer bestimmten Position entsprechende Achsenkreuz in das Achsenkreuz des Referenzsystems übergeht. Mit anderen Worten wird festgestellt, um welche Achse das Markierelement 7 gedreht werden muß, um die dem Achsenkreuz R entsprechende Referenzposition zu erreichen. Dies wird für alle längs der Bahnkurve bestimmten Positionen des Markierelementes 7 in dieser Weise durchgeführt und führt zu einer Anzahl unterschiedlich orientierter Momentan-Drehachsen. Diese Momentan-Drehachsen werden wieder auf ihre Streuung untersucht und bei ausreichend großer Streuung, d.h. beim Überschreiten eines vorgegebenen Schwellwertes, werden aus diesen Momentan-Drehachsen, beispielsweise durch Bestimmung von deren Schnittpunkt oder durch andere mathematische Verfahren die Koordinaten des Gelenkpunktes 15 errechnet.For each position of the marking element 7 during the movement sequence, the data processing system now calculates a momentary axis of rotation, which is selected such that the axis cross corresponding to a certain position passes into the axis cross of the reference system solely by rotation about this momentary axis of rotation. In other words, it is determined about which axis the marking element 7 has to be rotated in order to reach the reference position corresponding to the axis cross R. This is carried out in this way for all positions of the marking element 7 determined along the path curve and leads to a number of differently oriented instantaneous axes of rotation. These instantaneous axes of rotation are again examined for their scatter and if the scatter is sufficiently large, ie when a predetermined threshold value is exceeded, the coordinates of the articulation point 15 are calculated from these instantaneous axes of rotation, for example by determining their intersection or by other mathematical methods.
Wesentlich ist auch hier, daß die Streuung der unterschiedlichen Momentanorientierung ein Kriterium dafür bildet, ob aufgrund der Messung eine solche Berechnung sinnvoll ist oder nicht.It is also important here that the spread of the different instantaneous orientation forms a criterion for whether such a calculation makes sense or not based on the measurement.
Selbstverständlich ist auch bei diesem Verfahren möglich, die Bewegung der Tibia gegenüber dem Femur zu wiederholen, jedoch genügen hier in der Regel einige Abbiegebewegungen und Streckbewegungen des Beines, um eine ausreichende Anzahl von Meßpunkten für eine sehr genaue Gelenkpunktbestimmung zu erhalten. Of course, it is also possible with this method to repeat the movement of the tibia with respect to the femur, but as a rule a few turning movements and stretching movements of the leg are sufficient to obtain a sufficient number of measuring points for a very precise determination of the joint point.
Claims
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE10313747A DE10313747A1 (en) | 2003-03-27 | 2003-03-27 | Joint hinging and articulation investigation system is used for examination of problems with knee joints and uses pins with markers fixed to tibia and femur with positions sensed by navigation system |
| DE10313747 | 2003-03-27 | ||
| PCT/EP2004/001665 WO2004084750A1 (en) | 2003-03-27 | 2004-02-20 | Method and device for detecting a hinge point between two bones |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP1605853A1 true EP1605853A1 (en) | 2005-12-21 |
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ID=33038780
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP04713058A Withdrawn EP1605853A1 (en) | 2003-03-27 | 2004-02-20 | Method and device for detecting a hinge point between two bones |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US20060064043A1 (en) |
| EP (1) | EP1605853A1 (en) |
| JP (1) | JP2006523477A (en) |
| DE (1) | DE10313747A1 (en) |
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| US20060241405A1 (en) * | 2005-03-09 | 2006-10-26 | Aesculap Ag & Co. Kg | Method and apparatus for performing an orthodepic stability test using a surgical navigation system |
| EP1946718B1 (en) * | 2007-01-19 | 2010-06-09 | BrainLAB AG | Registration and stability test of a knee by recording two points on the knee |
| EP2178680B1 (en) * | 2007-07-30 | 2014-05-07 | Scuola Superiore Di Studi Universitari S. Anna | Wearable mechatronic device |
| EP2103259B1 (en) * | 2008-03-19 | 2012-01-25 | BrainLAB AG | Method and system for determination of a degree of deformity of an anatomical joint |
| GB0806813D0 (en) * | 2008-04-15 | 2008-05-14 | Smith & Nephew Orthopaedics Ag | Medical navigation method and system |
| WO2010082157A1 (en) * | 2009-01-16 | 2010-07-22 | Koninklijke Philips Electronics N.V. | Method for determining the rotation axis of a joint and device for monitoring the movements of at least one body part |
| JP2014117409A (en) * | 2012-12-14 | 2014-06-30 | Kawasaki Heavy Ind Ltd | Method and apparatus for measuring body joint position |
| AU2014331765A1 (en) | 2013-10-09 | 2016-04-28 | Nuvasive, Inc. | Surgical spinal correction |
| EP3157425A4 (en) | 2014-06-17 | 2017-11-15 | Nuvasive, Inc. | Systems and methods for planning, performing, and assessing spinal correction during surgery |
| EP4236852A1 (en) | 2020-10-30 | 2023-09-06 | MAKO Surgical Corp. | Robotic surgical system with cut selection logic |
| US12527632B2 (en) | 2020-12-15 | 2026-01-20 | Mako Surgical Corp. | Systems and methods for initial assessment warnings |
| USD1044829S1 (en) | 2021-07-29 | 2024-10-01 | Mako Surgical Corp. | Display screen or portion thereof with graphical user interface |
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|---|---|---|---|---|
| US4631676A (en) * | 1983-05-25 | 1986-12-23 | Hospital For Joint Diseases Or | Computerized video gait and motion analysis system and method |
| US5249581A (en) * | 1991-07-15 | 1993-10-05 | Horbal Mark T | Precision bone alignment |
| WO1995000075A1 (en) * | 1993-06-21 | 1995-01-05 | Osteonics Corp. | Method and apparatus for locating functional structures of the lower leg during knee surgery |
| DE19709960A1 (en) * | 1997-03-11 | 1998-09-24 | Aesculap Ag & Co Kg | Method and device for preoperatively determining the position data of endoprosthesis parts |
| EP1156740A4 (en) * | 1999-02-16 | 2004-03-17 | Frederic Picard | Optimizing alignment of an appendicular |
| US7623944B2 (en) * | 2001-06-29 | 2009-11-24 | Honda Motor Co., Ltd. | System and method of estimating joint loads in a three-dimensional system |
| DE10145587B4 (en) * | 2001-09-15 | 2007-04-12 | Aesculap Ag & Co. Kg | Method and device for testing a marking element for displacement |
| CA2509342A1 (en) * | 2001-12-11 | 2003-07-03 | Ecole De Technologie Superieure | Method of calibration for the representation of knee kinematics and harness for use therewith |
| US7402142B2 (en) * | 2002-09-23 | 2008-07-22 | Honda Giken Kogyo Kabushiki Kaisha | Method and processor for obtaining moments and torques in a biped walking system |
| US7359750B2 (en) * | 2003-02-22 | 2008-04-15 | Chul Gyu Song | Apparatus and method for analyzing motions using bio-impedance |
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2003
- 2003-03-27 DE DE10313747A patent/DE10313747A1/en not_active Withdrawn
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2004
- 2004-02-20 EP EP04713058A patent/EP1605853A1/en not_active Withdrawn
- 2004-02-20 JP JP2006504440A patent/JP2006523477A/en active Pending
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2005
- 2005-09-23 US US11/234,863 patent/US20060064043A1/en not_active Abandoned
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| Title |
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| None * |
| See also references of WO2004084750A1 * |
Also Published As
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| US20060064043A1 (en) | 2006-03-23 |
| DE10313747A1 (en) | 2004-10-28 |
| JP2006523477A (en) | 2006-10-19 |
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