DE202006010728U1 - Calibration system for surgical reference unit, comprising navigation unit and specific calibration elements - Google Patents

Abstract

A first reference element (14) could be attached to the pelvic bone (16) of a patient (12), a second (18) to the femur (20). If the femur (20) is moved, a curve relative to the motion of the bone (20) is created by the element (18) in relation to the first element (14) facilitating the determination of a rotation axis. The positions are determined by a navigation system (22). If an inertial sensor (34) is involved in the process a calibration unit (10) has to be employed and positioned relative to the reference element (14,18). The obtained data have to be processed and used in combination with a changeable coordinate system.

Description

The The present invention relates to a surgical calibration device for calibrating a position and / or orientation in space at least one surgical, with at least one inertial sensor equipped referencing unit of a surgical navigation system related to a coordinate system of space.

Further Below is a method for calibrating a position and / or an orientation in space of at least one surgical, with Referencing unit equipped with at least one inertial sensor a surgical navigation system based on a coordinate system of the room.

Known surgical navigation systems include referencing units, which is either electromagnetic radiation emitted by a detection device of the navigation system is reflected or self emit electromagnetic radiation emitted by the detection device can be received. In alternative embodiments, it is also known instead of using electromagnetic radiation ultrasound. A Position of the referencing unit in the room can be taken absolutely to a coordinate system defined by the detection device in ultrasound-based navigation systems by means of transit time measurements sent by the detection device and received again will be determined. A position and / or orientation determination emit and / or receive electromagnetic radiation Navigation systems is based on field changes. It is also possible, Position or orientation changes purely to capture video optically. For this purpose, navigation systems are used, the position and / or orientation detection purely via imaging Realize process.

aim The use of a navigation system is to move the referencing units to track in the room. For this purpose, as described above, absolute position data and / or orientations of the referencing unit by means of known navigation systems are determined. A trajectory the referencing unit leaves based on the determined position data and / or orientations reconstruct or calculate.

Becomes however, a surgical referencing unit with at least one Inertialsensor equipped, so a determination of position and / or Orientation data of the referencing unit in any Coordinate system no longer be done directly, but must be based on of position and / or changes in orientation be calculated. This is partly due to the fact that inertial sensors Sensors are with which due to position and / or orientation changes forces acting on them and / or accelerations can be measured. Will more than one inertial sensor used, especially when six inertial sensors used of which three are the forces and / or accelerations in three mutually linearly independent directions can detect and of which three rotational angle changes by three to each other linear independent axes can detect so can due to forces acting on the inertial sensors and / or Accelerations, position and / or orientation changes be clearly determined even in three-dimensional space.

There With inertial sensors directly no absolute position and / or Determine orientation data, it is therefore the task of the present Invention to propose a device of the type described above, with which it is possible the at least one referencing unit in a predetermined Referencing or calibrating the spatial coordinate system.

• – Bereitstellen einer Kalibriereinheit, deren Positions- und/oder Orientierungsdaten bezogen auf das Koordinatensystem vom Navigationssystem bestimmbar sind,
• – Bringen der Kalibriereinheit und der mindestens einen Referenzierungseinheit relativ zueinander in eine eineindeutige Kalibrierstellung, in welcher die Kalibriereinheit und die mindestens eine Referenzierungseinheit jeweils eine relativ zueinander definierte Kalibrierposition und/oder -orientierung einnehmen,
• – Bestimmen von Kalibrierpositions- und/oder -orientierungsdaten der Kalibriereinheit in der Kalibrierstellung mittels des Navigationssystems,
• – Berechnen von Kalibrierpositions- und/oder -orientierungsdaten der Referenzierungseinheit in der Kalibrierstellung aufgrund der Kalibrierpositions- und/oder -orientierungsdaten der Kalibriereinheit und
• – Zuweisen der für die mindestens eine Referenzierungseinheit berechneten Kalibrierpositions- und/oder -Orientierungsdaten in der Kalibrierstellung der mindestens einen Referenzierungseinheit.

A method of the type described in the introduction may in particular comprise:

• Providing a calibration unit whose position and / or orientation data can be determined by the navigation system relative to the coordinate system,
• Bringing the calibration unit and the at least one referencing unit relative to one another into a one-to-one calibration position, in which the calibration unit and the at least one referencing unit each assume a calibration position and / or orientation defined relative to each other,
• Determining calibration position and / or orientation data of the calibration unit in the calibration position by means of the navigation system,
• Calculating calibration position and / or orientation data of the referencing unit in the calibration position on the basis of the calibration position and / or orientation data of the calibration unit and
• Assigning the calibration position and / or orientation data calculated for the at least one referencing unit in the calibration position of the at least one referencing unit.

By the method, it is possible to assign the at least one referencing unit position and / or orientation data related to the coordinate system. Position and / or orientation changes that are due to acting on the at least one inertial sensor Forces and / or accelerations can thus be determined in a simple manner with respect to the coordinate system of the room. The method is simple to carry out, since the calibration unit whose position and / or orientation in space can be determined by the navigation system serves to calibrate the at least one referencing unit. For this purpose, the method provides, in particular, for the at least one referencing unit and the calibration unit to be brought into a calibration position that is unambiguous relative to one another and then position and / or orientation data to be assigned to the at least one referencing unit, in particular on the basis of determined calibration position and / or orientation data Calibration unit in the calibration position, which can be determined for example by means of the navigation system. The at least one referencing unit can be assigned directly to this data, or else position and / or orientation data resulting from the one-to-one relative position of the at least one referencing unit and the calibration unit in the calibration position. The method described is outstandingly suitable for fast and simple calibration or referencing of the at least one referencing unit. In particular, the proposed calibration method can be repeated as often as desired. Repeated referencing or calibration of the at least one referencing unit may be required in conventional inertial sensors because they have a time-dependent drift, so that in particular in long-term measurements inaccuracies of forces and / or accelerations acting on the inertial sensors can occur, resulting in the consequence then inaccuracies in the determination of position and / or orientation data he give. Furthermore, additional calibrations and / or referencing may be required if the at least one referencing unit is subjected to only small changes in position.

Advantageous it is, if as a coordinate system a not fixed coordinate system is given and if a coordinate origin of the non-stationary Coordinate system through the calibration position and / or orientation data the at least one referencing unit or the calibration unit is specified in the calibration position. By not stationary Coordinate system can indeed no absolute position and / or orientation data in the room, however, in particular relative positions with respect to the origin of the coordinate non-stationary coordinate system can be determined. This method is particularly simple, associated with a reduced computational effort and is particularly suitable for Cases, in which it is not an absolute referencing in a fixed coordinate system, For example, an operating room, arrives.

Further it can be cheap be calibrated if at least two referencing units are calibrated, if as a coordinate system a non-stationary coordinate system is given and if a coordinate origin of the non-stationary Coordinate system by one of the at least two referencing units is given. Position and / or orientation changes can then in a simple manner relative to one of the at least two referencing units be determined. This method can be particularly advantageous be used if no absolute referencing in an example required for an operating room coordinate system is.

If for example, a referencing with respect to a fixed coordinate system, For example, referring to an operating room, it is desired it is advantageous if a coordinate origin fixed in space an absolute coordinate system is specified when the calibration unit is brought into an original calibration position, in which the Calibration unit in a defined relationship to the fixed Coordinate origin is positioned, and if origin position and / or orientation data of the calibration unit in the original calibration position based on the fixed coordinate origin of the calibration unit be assigned. This procedure makes it possible, in particular Homing units equipped with at least one inertial sensor along with referencing units, the electromagnetic radiation send out and / or reflect and equipped without inertial sensors or are navigable by means of ultrasound or video optics are, from navigation systems described above and in conjunction to use with such navigation systems.

In order to a calibration or referencing by the navigation system or parts of it can be done automatically, it is convenient if a calibration signal is generated when the calibration unit and the at least one referencing unit the calibration position taking. The calibration signal then indicates when the calibration unit and the at least one referencing unit take the position in which a calibration or a referencing made shall be.

According to a preferred variant of the method described, it is favorable if the calibration signal is generated only after a holding time t _H , while the calibration unit and the at least one referencing unit occupy the calibration position without or substantially without relative movement. Thus, calibration or referencing errors are minimized or even frequently excluded altogether.

Cheap is it, if in the calibration position, an actuating element is actuated and if the calibration signal is only during or in response to an actuation of the actuating element is produced. In particular, it can be ensured in this way that only with defined actuation of the actuating element a calibration signal is generated. This can, for example, by easy operation of the actuating element be generated, namely when pressing and / or when releasing of the actuating element. It would be possible It also means that the calibration signal is generated only when the actuator while a predetermined or predetermined operating time has been permanently actuated.

advantageously, becomes the actuator by the calibration unit and / or the at least one referencing unit actuated. In particular, it is possible that the actuating element in the calibration position automatically by the calibration unit or the at least one referencing unit is actuated. For example, the actuator could on the calibration unit and / or the at least one referencing unit to be ordered.

Basically it would be possible as actuator to use an optical or acoustic switching element. Also Proximity switch, inductive or capacitive design would be possible. Especially easy and in a defined way by operation of the actuating element generate a calibration signal when a mechanical as an actuator Switch is used, in particular in the form of a button, hand switch or a footswitch. Will not the actuator on the calibration unit and not in the at least one referencing unit arranged, can these two units are made very small. In particular, it would be through a separation of actuator and calibration unit or referencing unit, for Example also by spatial Separation, also possible, that actuator from a person to press for example, not present in an operating room is. So can also not sterilizable actuators be used.

Advantageous if it is only after the calibration signal has been present that the calibration position and / or orientation data in the calibration position of the navigation system determines the calibration position and / or orientation data of at least one referencing unit in the calibration position calculated and the for the at least one referencing unit calculated Kalibrierpositions- and / or orientation data in the calibration position of the at least one Be assigned to the referencing unit. By this procedure An accuracy of the calibration procedure can be significantly increased especially when the calibration signal is only generated when the calibration unit and the at least one referencing unit take the calibration position.

conveniently, An origin calibration signal is generated when the calibration unit assumes the origin calibration position. In a defined way, positional and / or orientation data of a coordinate origin, for example a fixed coordinate system associated with the calibration unit become.

In order to increase the accuracy of a referencing or calibration of the calibration unit with respect to the origin of coordinates, it is advantageous if the origin calibration signal is generated only after a _hold time t _{H_Ursprung} , during which the calibration unit assumes the original calibration position motionless or substantially motionless.

According to one preferred variant of the method described can be provided be that in the origin calibration position, an origin Kalibrierbetätigungselement actuated and that the origin calibration signal is only during or in response to an actuation of the Origin Kalibrierbetätigungselement is produced. Thus, in particular, an automatic referencing or calibrating the calibration unit based on the origin of the coordinates.

For an automatic Initialization of the calibration process, it is beneficial if the origin calibration actuator through the calibration unit or a referencing device actuated becomes. As a referencing device, for example, a device serve, relative to the calibration unit in a defined original calibration position can be brought. For example, the referencing device have a receptacle into which at least a part of the calibration unit can intervene in the origin calibration position. It would also be conceivable as referencing device, the at least one referencing unit to use.

It would be readily possible to use as an origin Kalibrierbetätigungselement an optical or inductive or capacitive switching element. However, it is particularly simple if a mechanical switching element is used as the originating calibration actuating element, in particular a mechanical pushbutton or switch or a footswitch. Thus, automatically or by an operator specifically by means of the origin calibration actuating element an origin calibration signal can be generated or initialized.

advantageously, only after the presence of the origin calibration signal the origin position and / or orientation data of the calibration unit in the original calibration position based on the fixed coordinate origin of the calibration unit assigned. This can ensure that a calibration or referencing the calibration unit with respect to the origin of the coordinates only then takes place when the calibration unit the required Relative position relative to the origin of coordinates occupies or has taken.

In order to with the navigation system is not mistakenly wrong or inaccurate Position and / or orientation data of the at least one referencing unit be detected, it is advantageous if a navigation operation of the navigation system for tracking any movements of the at least a referencing unit is only released if all for the Navigation required Referencing with the calibration unit calibrated based on a common coordinate system. This ensures in particular that the navigation system is correct Position and / or orientation data of the at least one referencing unit be determined.

In order to avoid or at least minimize the determination of inaccurate position and / or orientation data of the at least one referencing unit and of the calibration unit, it is advantageous if a navigation _{mode is} limited to a predefinable operating time t _operation . The operating time may, for example, be set in a range of 1 second to 60 minutes, preferably 10 seconds to 20 minutes. In particular, the limitation of the navigation system to a predefinable operating time prevents inaccuracies in determining the position and / or orientation of the at least one referencing unit due to a drift of the at least one inertial sensor of the at least one referencing unit after a certain operating time.

Advantageously, the operating time t _operation automatically starts to run when all referencing units have been calibrated with the calibration unit relative to a common coordinate system. In particular, it may also be considered that the operating time t _operation starts to run when the first of the reference units to be calibrated or referenced has been calibrated or referenced.

Preferably, after the operating time t _{operation has} elapsed, an optical and / or acoustic warning signal is emitted and / or the navigation _{mode is} automatically ended. Thus, it is possible to prevent inaccurate or incorrect values for the position and / or the orientation of the at least one referencing unit from being determined due to a so-called "drifting away" of the at least one inertial sensor.

The procedure is particularly simple and safe when the operating time t _{operation is} monitored by the navigation system.

Depending on the type and type of inertial sensors used, it is advantageous if the operating time t _{operation is} limited to a maximum time in the range of 1 second to 60 minutes, preferably in a range of 10 seconds to 20 minutes. For long-term stable inertial sensors with very little drift, the maximum time can be up to 30 or 40 minutes.

Basically it would be without Other possible to use a calibration unit equipped with conventional marker elements is, i. with marker elements that are either themselves electromagnetic Emitting radiation by the detection device of the navigation system can be received, or sent to the navigation system electromagnetic radiation can react. Of course it would be too possible, one Calibration unit equipped with marker elements is which of video-based navigation systems or are navigable on ultrasound-based navigation systems. However, it is advantageous if one with at least one inertial sensor equipped calibration unit is provided whose positional and / or orientation data related to the coordinate system of Navigation system are detectable. This allows, for example, the calibration unit and the at least one referencing unit to initialize simultaneously, so to speak to "zeros". A calibration of at least one Referencing unit and / or the calibration unit can be before or after initialization. Furthermore, the equipment has the calibration unit with at least one inertial sensor also the Advantage that the navigation system as a whole built a simple can be, for example, it can be entirely optical Detection device can be dispensed with. Furthermore, in particular also be dispensed with a detection device, by itself Radiation can be emitted. In addition, it would also be possible if more than one referencing unit is provided, one of the referencing units itself to be used as a calibration unit.

According to a preferred variant of be It can be provided that the calibration unit and the at least one referencing unit each have at least one transmission unit and that the at least one transmission unit transmits changes in the position and / or orientation data of the calibration unit and / or the referencing unit to the navigation system or to a detection device thereof become. The units formed in this way as active referencing units or as active calibration unit make an active detection device that can emit radiation itself superfluous. In particular, it would be possible to use electromagnetic or infrared radiation emitting transmitting units, for example, so-called Bluetooth transmitting units are mentioned here, which can communicate in a standardized form with a Bluetooth receiving device of the navigation system.

Preferably is used to determine the position and / or orientation data of Calibration unit and the at least one referencing unit a navigation system is used which comprises an evaluation unit, which is formed such that by means of the at least one Inertial sensor measured acceleration values absolute position and / or orientation data for the calibration unit and the at least one referencing unit can be calculated are. The use of such a navigation system has the Advantage that a position and / or orientation determination of Calibration unit and the at least one referencing unit fully automatic possible is.

Cheap is it, if from the measured acceleration values position and / or orientation change data the calibration unit and the at least one referencing unit calculated on the coordinate system and if off the calculated position and / or orientation change data absolute position and / or orientation data of the calibration unit and the at least one referencing unit with respect to Coordinate system can be calculated. This procedure has the Advantage that if no absolute position and / or modification data the calibration unit and the at least one referencing unit must be determined the calculated position and / or orientation change data for one relative position determination can be used.

conveniently, is an inertial sensor unit as at least one inertial sensor uses at least three linear acceleration sensors and three rotational acceleration sensors with which the calibration unit and / or the at least one referencing unit acting accelerations and / or forces in three mutually linear independent Directions and time-dependent measured by three relative to each other linearly independent axes of rotation become. With such inertial sensor units, all for a three-dimensional Position and / or orientation determination in a coordinate system required measured values are determined.

• – ein Navigationssystem mit einer Datenverarbeitungseinheit, wobei das Navigationssystem und die Datenverarbeitungseinheit derart ausgebildet und programmiert sind, dass Positions- und/oder Orientierungsdaten der Referenzierungseinheit bezogen auf das Koordinatensystem bestimmbar sind,
• – eine Kalibriereinheit, deren Positions- und/oder Orientierungsdaten bezogen auf das Koordinatensystem vom Navigationssystem bestimmbar sind,

wobei die Kalibriereinheit und die mindestens eine Referenzierungseinheit relativ zu einander in eine eineindeutige Kalibrierstellung bringbar sind, in welcher die Kalibriereinheit und die mindestens eine Referenzierungseinheit jeweils eine relativ zueinander definierte Kalibrierposition- und/oder -orientierung einnehmen, wobei das Navigationssystem und die Datenverarbeitungseinheit ferner derart ausgebildet und programmiert sind, dass Positions- und/oder Orientierungsdaten der Kalibriereinheit bezogen auf das Koordinatensystem bestimmbar sind, dass Kalibrierpositions- und/oder -orientierungsdaten der Referenzierungseinheit in der Kalibrierstellung auf Grund der Kalibrierpositions- und/oder -orientierungsdaten der Kalibriereinheit berechenbar sind und dass die für die mindestens eine Referenzierungseinheit berechneten Kalibrierpositions- und/oder -orientierungsdaten in der Kalibrierstellung der mindestens einen Referenzierungseinheit zuweisbar sind.The object stated at the outset is achieved by a surgical calibration device for calibrating a position and / or an orientation in space of at least one surgical referencing unit of a surgical navigation system equipped with at least one inertial sensor with respect to a coordinate system of the room, comprising:

• A navigation system having a data processing unit, wherein the navigation system and the data processing unit are designed and programmed such that position and / or orientation data of the referencing unit can be determined with reference to the coordinate system,
• A calibration unit whose position and / or orientation data can be determined by the navigation system relative to the coordinate system,

wherein the calibration unit and the at least one referencing unit can be brought into a one-to-one calibration position relative to each other, in which the calibration unit and the at least one referencing unit each assume a calibration position and / or orientation defined relative to each other, wherein the navigation system and the data processing unit are further configured and programmed, that position and / or orientation data of the calibration unit relative to the coordinate system can be determined, that calibration position and / or orientation data of the referencing unit in the calibration position can be calculated on the basis of the calibration position and / or orientation data of the calibration unit and that for the at least one referencing unit calculated calibration position and / or orientation data in the calibration position of the at least one referencing unit can be assigned.

With the surgical calibration device proposed according to the invention, it is possible to easily calibrate reference units of surgical navigation systems equipped with at least one inertial sensor in relation to a coordinate system of the room. This calibration, also referred to as referencing, can easily be carried out by means of the calibration unit and the navigation system and makes it possible to use referencing units equipped with inertial sensors, in particular for determining the position and / or orientation of chirur gical devices, such as instruments and / or implants.

Advantageous is it when the navigation system and the data processing unit are further designed and programmed such that as a coordinate system a non-fixed coordinate system can be specified and that a Coordinate origin of the non-stationary coordinate system the calibration position and / or orientation data of the at least a referencing unit or the calibration unit in the calibration position can be specified. It is possible with such a calibration device, too a relative position and / or orientation determination of at least a referencing unit based on a non-stationary coordinate system make.

According to one preferred embodiment of Invention may be provided that the navigation system and the Data processing unit further designed and programmed are that at least two homing units can be calibrated are that as a coordinate system a non-fixed coordinate system is specifiable and that a coordinate origin of nothing stationary Coordinate system by one of the at least two referencing units can be specified. With the thus developed navigation system is it possible, one the at least two homing units as nothing stationary Coordinate origin of a coordinate system to define. Especially it is also possible one of the at least two referencing units also as a calibration unit to use. The only condition for this is that the at least two referencing units relative to each other in a one-to-one Calibration position can be brought.

Advantageous it is when an origin calibration gauge is provided and when the navigation system and the data processing unit further such are trained and programmed that one by the origin calibration gauge defined and fixed in space coordinate origin of a absolute coordinate system can be specified if the calibration unit in an origin calibration position relative to the origin calibration gauge can be brought, in which the Calibration unit in a defined relationship to the fixed Coordinate origin is positioned, and if origin position and / or orientation data of the calibration unit in the original calibration position based on the fixed coordinate origin of the calibration unit are assignable. In particular, the origin calibration theory makes it possible to the calibration unit into a one-to-one origin calibration position relative to a coordinate origin of an absolute fixed in space Coordinate system. You could also do the calibration to define the coordinate origin of the coordinate system. For example, over The origin calibration also links between inertial sensors equipped referencing units and with conventional Reached marker elements equipped referencing units become. For this can For example, the origin calibration gauge with conventional Be equipped with marker elements that make it possible with a detection device of the navigation system, the position of the origin calibration gauge to be determined in the room.

advantageously, a calibration signal generating device is provided for generating a calibration signal when the calibration unit and the at least a referencing unit occupy the calibration position. The Calibration signal generating device thus serves inter alia the purpose of to generate a calibration signal, if the geometric conditions for one Calibration or a referencing are met, i. if the calibration unit and the at least one referencing unit the calibration position taking.

Conveniently, the calibration signal generating device is designed such that the calibration signal is generated only after a holding time t _H , during which the calibration unit and the at least one referencing unit occupy the calibration position without or substantially without relative movement. Such a calibration signal generating device can ensure that a calibration is only performed when the calibration unit and the at least one referencing unit actually assume the desired one-to-one calibration position.

Advantageous it is when at least one actuator is provided, which is operable in the calibration position, and when with the calibration signal generating device, the calibration signal only during or as a result of an operation of the at least one actuating element can be generated. Requirement for the generation of a calibration signal is thus an actuation of the at least one actuating element. In this case, the calibration signal generating device can be designed in this way be that the calibration signal is constantly during an operation of the actuating element is produced. It can also be provided that the calibration signal immediately upon actuation of the actuating element is produced. Alternatively, it is also possible to use the calibration signal only after the hold time to generate, i. that the actuating element at least during an uninterrupted period of time corresponding to the holding time got to.

Preferably, the at least one actuating element is arranged such that it by the calibration unit and / or the at least one Refe can be actuated zenzierungseinheit. Thus, in particular, it can be achieved that the actuating element is necessarily actuated when the calibration unit and the at least one referencing unit assume the calibration position.

Especially simply the structure of the calibration device, if that at least an actuator a mechanical switching element, in particular a button or a footswitch includes. It would be possible it too, the actuator in the form of an optical switch or as a proximity switch in inductive or capacitive design. A hand or foot switch as an actuator provides for the possibility of for example, a surgeon generating a calibration signal by the calibration signal generating device in the desired Way initialized or triggered.

Especially simple is a calibration of the at least one referencing unit or perform the calibration unit, if the at least one actuator at the at least one referencing unit, at the calibration unit and / or is located at the origin calibration gauge. In particular, can the actuator be arranged such that it is automatically detected by the referencing unit, the calibration unit and / or the origin calibration gauge is actuated, if the at least one referencing unit and the calibration unit take the calibration position and / or the calibration unit and the origin calibration gauge assumes the origin calibration position.

According to one preferred embodiment of Invention may also be provided that the navigation system and the data processing unit is designed and programmed in this way are that only after the presence of the calibration signal, the calibration position and / or orientation data of the calibration unit in the calibration position determinable by means of the navigation system, the calibration position and / or orientation data of the referencing unit in the calibration position predictable and the for the at least one referencing unit calculated calibration and / or orientation data in the calibration position of at least a referencing are assignable. With such a calibration device can be prevented inadvertently a calibration carried out becomes. requirement for a calibration is thus in such a calibration device always the presence of the calibration signal.

conveniently, an origin calibration signal generating device is provided for generating an origin calibration signal when the calibration unit receives the Origin calibration position occupies. This makes it possible to get one generated signal when the calibration unit, the original calibration position occupies. For example, the source calibration signal may be used be used, a calibration of the calibration unit in relation to trigger on the origin of the coordinate system.

It is favorable if the origin calibration _{signal generating device is embodied} such that the origin calibration _{signal can be} generated only after a _hold time t _{H_Ursprung} , during which the calibration unit assumes the original calibration position motionless or essentially motionless. This development prevents accidental origin calibration from being made. In particular, due to the duration of the hold time, a safe and accurate source calibration can be achieved.

Cheap is if an origin calibration actuator is provided, which is operable in the origin calibration position, and if the origin calibration signal is only while or as a result of an operation of the originating calibration actuator can be generated. With the origin calibration actuator also part may be the origin calibration signal generator The latter, in particular, are initialized to the origin calibration signal to create. Thus, the origin calibration actuator also serves as a fuse element, to prevent the origin calibration signal from becoming unwanted Way is generated. In addition, would be it is conceivable, the origin calibration signal after the end of the operation of the origin Kalibrierbetätigungselements to create.

conveniently, is the origin calibration actuator arranged such that it passes through the calibration unit, a referencing unit or the origin calibration gauge is operable. That's the way it is possible, if the units to be calibrated relative to each other or Parts assume the origin calibration position that the origin calibration actuator automatically operated becomes.

optional would it be possible, the origin calibration actuator in the form of an optical switch or a proximity switch. It is advantageous, however, if the origin actuator a button or a footswitch includes. Of course can the button and also the footswitch comprise optical or inductive or capacitive proximity switches. The advantage Such an embodiment is in particular that also an operation as a result of mechanical contact is possible.

According to a preferred embodiment of the invention can be provided that the Navi Furthermore, the gation system and the data processing unit are designed and programmed in such a way that the origin position and / or orientation data of the calibration unit in the origin calibration position can be assigned to the calibration unit based on the fixed coordinate origin only after the presence of the origin calibration signal. With the navigation system thus formed, a mis-calibration or an incorrect calibration can be prevented.

advantageously, the navigation system and the data processing unit are further designed and programmed such that a navigation operation of the Navigation system for tracking any movements of the at least one Referencing unit is only then released, if all for the navigation operation required referencing units with the calibration unit calibrated based on a common coordinate system. In this way, the navigation system can be prevented in unwanted Mode changes into an operating mode, in which position and / or Orientation data of at least one referencing unit determinable are, the so-called "navigation mode". This can be avoided that incorrect or erroneous coordinates are determined.

Preferably, the navigation system comprises an operating time presetting unit, with which a navigation operation to a predefinable. Operating time t _{operation is} limited. In particular, it is prevented that the navigation mode is used too long, which due to a drift of the inertial sensors can lead to an intolerable deviation in the determination of position and / or orientation data of the at least one referencing unit.

It is advantageous if the navigation system and the data processing unit are further configured and programmed such that the operating time t _operation predeterminable by the operating time specification unit automatically starts to run when all the referencing units have been calibrated with the calibration unit relative to a common coordinate system. With such a calibration device, an operator does not need to start the navigation mode himself, but this can be started automatically if all prerequisites are met that allow accurate position and / or orientation data determination. It should be noted that a referencing unit can also be designed or used as a calibration unit.

Furthermore, errors in the determination of position and / or orientation data are prevented by providing a warning signal generating device with which an optical or acoustic warning signal can be emitted after the operating time t _{operation has} elapsed and / or with which the navigation operation can be terminated automatically. For example, an operator who has been warned by the visual and / or audible warning signal can end the navigation mode of the navigation system. To avoid operating errors, alternatively the navigation mode can also be ended automatically after the predefined operating time has elapsed.

The navigation system preferably includes an operating time monitoring device with which the operating time t _{operation can be} monitored. Thus, it is possible to prevent the navigation mode from being undesirably carried out longer than it should be due to the drifting property of the inertial sensors.

In order to avoid or minimize errors in the position and / or orientation data determination on the basis of a possible drift of the at least one inertial sensor, it is favorable if an operating time limiting device is provided for limiting the operating time t _operation to a maximum time in a range of 1 second to 60 minutes, preferably in a range of 10 seconds and 20 minutes.

advantageously, the calibration unit comprises at least one inertial sensor. It would be conceivable, also a calibration unit in the form of a conventional so-called "pointers" to be used, ie a palpation or palpier instrument equipped with marker elements is whose positions in space of conventional navigation systems using electromagnetic radiation, by means of ultrasound or by means of video optical methods can be detected. But only become referencing units and also the calibration unit equipped with inertial sensors, then overall the structure of the navigation system simplifies, there are not two different methods of detection of position and orientation data of the at least one referencing unit and the calibration unit are required.

Around Measurements or other data from the calibration unit and the at least forward a referencing unit to the navigation system or to transfer is it cheap if the calibration unit and the at least one referencing unit each comprise at least one transmitting unit for transmitting of readings or changes the position and / or orientation data of the calibration unit and the at least one referencing unit to the navigation system or to a detection device thereof.

Preferably, the navigation system comprises For determining the position and / or orientation data of the calibration unit and the at least one referencing unit, an evaluation unit is configured such that absolute position and / or orientation data for the calibration unit and / or the at least one of the acceleration values measured by the at least one inertial sensor Referencing be calculated. For example, the evaluation unit may be part of the detection device or of the data processing device or of the navigation system.

According to one another preferred embodiment The invention can be provided that the evaluation unit such is formed and / or programmed that from the measured acceleration values Position and / or Orientation change data the calibration unit and the at least one referencing unit based on the coordinate system are calculable and that from the calculated position and / or orientation change data absolute position and / or orientation data of the calibration unit and the at least a referencing unit based on the coordinate system calculable are. Optionally in the case of only relative calibration relative to a non-stationary one Coordinate system the position and / or orientation change data used for relative position and / or orientation data to calculate at least relative position and / or orientation data to investigate.

Preferably is an inertial sensor unit comprising the at least one inertial sensor provided, which at least three linear acceleration sensors and three yaw rate or rotational acceleration sensors, with those on the calibration instrument and / or the at least one Referencing acting accelerations in three to each other linearly independent Directions and three relative to each other linearly independent axes of rotation time-dependent are measurable. With such an inertial sensor unit position changes the calibration unit and / or the at least one referencing unit be detected in the room.

Around a unique relative position between the calibration unit and the at least one referencing unit in the calibration position to be able to pretend is it cheap if at least one calibration gauge is provided, wel che at least a calibration recording for at least partially recording the calibration unit in the calibration position. In cases where the calibration unit is formed by a referencing, then can for example, two referencing units relative to each other be brought into a one-to-one calibration position, for example by being engaged.

Cheap is it, if the at least one calibration gauge at the at least one Referencing unit is arranged. Alternatively, she could too be arranged on the calibration unit.

Especially it simply becomes relative, the calibration unit and the at least one referencing unit to bring one another in a one-to-one calibration position, if the at least one calibration receptacle one to a part of the calibration unit Corresponding recess is in this part of the calibration form-fitting insertable is.

ever after, whether by means of the calibration gauge a point, a direction or a point with associated direction be given, it is advantageous if the at least a calibration gauge a one-, two- or three-dimensional calibration gauge for one Position and / or orientation calibration of at least a referencing unit and the calibration unit relative to each other is. For example, a one-dimensional calibration gauge can be used in Formed a bore, with a cylindrical shaft or such shaft portion brought in a defined orientation can be. For example, a two-dimensional calibration gauge forms out in the form of a groove, a three-dimensional calibration gauge in the form of a non-round blind hole or a non-round groove with one-sided stop.

advantageously, the origin calibration gauge has at least one origin calibration shot for at least partially accommodating the calibration unit in the Origin calibration position on. So the calibration unit can at least partially introduced into the calibration receptacle to a one-to-one To assume the original calibration position.

Especially simply the construction of the origin calibration gauge, if the at least an origin calibration shot to a part of the calibration unit is corresponding recess, in which the part of the calibration unit is positively inserted.

Preferably, the origin calibration actuator and / or the confirmation element are manually operable. For example, an operator can actuate the respective actuating element when the calibration unit, the referencing unit and / or the calibration gauge assume the required one-to-one relative position. Manually actuatable may also mean that the respective actuating element is actuated as a result of contact or engagement with the calibration unit, the at least one referencing unit or the at least one calibration gauge can.

One particularly simple and compact construction of the calibration device let yourself achieve that the origin Kalibrierbetätigungselement and / or the actuating element one at the origin calibration gauge and / or at least one Referencing unit or arranged on the calibration gauge microswitch include.

The following description of preferred embodiments of the invention used in conjunction with the drawings for further explanation. Show it:

1 : a schematic representation of a calibration device according to the invention;

2 : a schematic representation of an origin calibration gauge with inserted calibration unit;

3 : A plan view of the origin calibration gauge in 2 towards an origin calibration shot;

4 : an arrangement similar 2 with an origin calibration gauge with an origin calibration actuator;

5 : a schematic representation of a calibration of a referencing unit in a stationary coordinate system;

6 a schematic representation of a relative calibration of Referenzierungseinheiten in a non-fixed coordinate system;

7 : a schematic representation of a calibration method similar to the 6 sketched procedure;

8th a perspective view of a calibration gauge;

9 : A top view of the calibration gauge 8th ;

10 a perspective view of another embodiment of a calibration gauge;

11 a perspective view of another calibration gauge;

12 : A top view of the calibration gauge 11 ;

13 a perspective view of another embodiment of a calibration gauge for point-direction calibration;

14 : a top view of the calibration gauge in 13 ;

15 a perspective view of a "two" or "three-dimensional" calibration gauge;

16 : A plan view of a section of the calibration gauge in 15 ;

17 a perspective view of another embodiment of a "two" or "three-dimensional" calibration gauge;

18 : a top view of a part of in 17 illustrated calibration gauge;

19 a perspective view of another "three-dimensional" calibration gauge; and

20 : A perspective view of two engaged in a calibration position Kalibrierlehren.

An example for the application of a navigation system is in 1 shown. To determine, for example, a center of a knee joint of a patient 12 becomes a first referencing unit 14 on a pelvic bone 16 of the patient 12 set a second referencing unit 18 on a femur 20 of the patient 12 , The definition of the referencing units 14 and 18 on the patient 12 usually takes place by means of bone screws or bone pins. Will the femur 20 relative to the pelvic bone 16 moves, so describes the referencing unit 18 a trajectory relative to the referencing unit 14 , from which a center of rotation of the associated hip joint of the patient 12 determine.

For detecting the position and / or orientation of the referencing unit 14 and 18 serves a navigation system 22 , This comprises one or more data processing units 24 , an input device 26 in the form of a keyboard and an output device 28 in the form of a screen on which the input and / or output values can be displayed. The navigation system 22 further comprises a detection device 30 to get from the referencing units 14 and 18 to receive transmitted data signals. Serve for preferably three transmitting and / or receiving units 32 which in particular can emit and receive electromagnetic radiation in conventional systems. Of course, other navigation systems could be used that send and receive ultrasound to determine by means of transit time measurements positions of Referenzierungseinheiten in space. Instead of the three transmitting and / or receiving units 32 could also Bilderzeu tion devices are used with which using video-optical method generated images are evaluated and can be determined from these directly position and / or orientation data of the referencing. In particular, such transmitting and / or receiving units 32 also suitable for radiation actively emitted by referencing units or reflected by them and originally from the transmitting and / or receiving units 32 to detect emitted signals.

The present invention is concerned with the calibration of a position and / or an orientation in space of at least one surgical referencing unit of a surgical navigation system equipped with at least one inertial sensor with reference to a coordinate system of the room. Therefore, at least one of the two referencing units 14 respectively 18 equipped with at least one inertial sensor. Inertial sensors are used to measure forces or accelerations acting on them. They thus provide measured values when moved from a first position to a second position that correspond to forces and / or accelerations acting on them as a result of the position and / or orientation change. For determining three-dimensional position and / or orientation changes of the referencing units 14 respectively 18 are inertial sensor units 34 provided, which comprise at least six inertial sensors, namely three linear acceleration sensors and three rotation rate or rotational acceleration sensors, which are arranged so that forces or accelerations in three mutually linearly independent directions can be detected. Furthermore, the referencing units 14 respectively 18 preferably equipped with transmitting units, not shown, to measure the force or acceleration values measured by the at least one inertial sensor to the detection device 30 of the navigation system 22 transmitted, for example by means of Bluetooth technology.

Since an absolute determination of the position and / or orientation of homing units equipped with inertial sensors is not possible, and furthermore inertial sensors are subject to a more or less drift due to the design, at least one calibration or referencing of the referencing units is required 14 and 18 to specify their position and / or orientation with respect to a coordinate system. The drift of the inertial sensors, so an increasing with increasing measuring duration deviation of the actually measured values determined by the theoretically expected values, also makes it necessary, an operating time t _operation of the navigation system 22 to limit a time that is significantly shorter than a drift time t _{drift of} the inertial sensors, which can be defined, for example, as the time that elapses until a deviation of the position and / or orientation determined by the inertial sensors is greater than a predetermined tolerable deviation which may be in a range of 0.1% to 5%, for example. It is therefore not only sensible, but because of the most accurate desired position and / or orientation detection of Referenzierungseinheiten 14 and 18 even advised to regularly recalibrate or re-reference their position and / or orientation in the coordinate system.

For calibration of the referencing units 14 respectively 18 serves a total with the reference numeral 10 provided, inventive surgical calibration device, which is a calibration unit 36 includes. The latter can be designed in particular in the form of a tactile or palpation instrument, which is also known or known as a so-called "pointer". The calibration unit 36 is in a first variant with an in 1 illustrated marker element 38 equipped, which four in a predefined spatial spatially mutually defined electromagnetic radiation reflecting balls 40 includes. These can, for example, from the detection device 30 Reflect emitted electromagnetic radiation, so that the position of the marker element 38 in the room by means of the navigation system 22 is clearly determinable. Furthermore, the marker elements 38 also be actively formed, that is, instead of the balls 40 Active transmitting elements can be provided. Instead of in 1 illustrated marker element 38 It is also possible to provide a marker element which can be navigated by means of navigation systems which react to electromagnetic radiation which is based on ultrasound or which can detect a position and / or orientation of the marker element in space with video-optical methods. Alternatively, instead of the marker element 38 Also, at least one inertial sensor, preferably an inertial sensor unit with six inertial sensors, namely three linear acceleration and three rotational acceleration sensors, be provided, which are arranged and configured such that they can detect accelerations and / or forces acting on the calibration unit in three mutually linearly independent directions , Optionally, it would also be conceivable, in addition to the inertial sensor unit, not shown, also the marker element 38 provided. In the case of a calibration unit equipped with at least one inertial sensor, preferably also a transmitting unit is provided, with which the measured values for the navigation system acquired by the at least one inertial sensor are provided 22 can be transmitted. Of course, a wired calibration unit, so with the Navigation system can be provided via a cable connected calibration unit, which has the advantage that no disturbing external influences can interfere with data transmission between the calibration unit and the navigation system. In particular, a data exchange can take place by means of known Bluetooth technology.

A calibration of the referencing units 14 and 18 For example, in a fixed coordinate system 60 of the room, for example an operating room. In particular, a coordinate origin can be determined by means of an origin calibration gauge 42 To be defined. This is a stationary arranged in space, for example on a table top 44 or an operating table 46 arranged device holding a receptacle 48 in which a part of the calibration unit 36 is insertable, preferably positive fit and one-to-one. Unanimous in this case means that there is only one possibility, the calibration unit 36 in the recording 48 introduce.

The example in 2 illustrated origin calibration gauge 42 includes a recording 48 with a hexagonal cross-section that tapers conically at its closed end. A distal end 49 the calibration unit 36 with a palm tip 50 is corresponding to the recording 48 trained, that is, starting from the Palpierspitze 50 widens the distal end 49 conical and is characterized by a hexagonal section in cross section 51 continued. Around the distal end 49 the calibration unit 36 easier in the recording 48 to be able to introduce, this extends from its closed end facing away funnel-shaped, so that an inner surface 52 this cone-shaped portion a sliding surface for the distal end 49 the calibration unit 36 forms.

The origin calibration gauge 42 , which can be optionally attached to a rail arranged circumferentially arranged in the operating room or on an instrument table, thus defining a so-called absolute or world coordinate system 60 , Of course, it is also conceivable, the origin calibration gauge 42 be provided with a different inner cross section, so that a distal end of the calibration unit 36 , which is then shaped according to the key-lock principle only in a one-to-one orientation in the recording 48 can be introduced.

To the calibration unit 36 that through the origin calibration gauge 42 defined stationary coordinate system 60 assign, so perform an absolute referencing or calibration, the distal end 49 the calibration unit 36 in the recording 48 the origin calibration gauge 42 introduced. In one possible embodiment, the elongated cylindrical body 54 the calibration unit 36 a switch 56 be arranged. Will the switch 56 actuated, for example, by an operator, this has due to a corresponding design of the navigation system 22 entail that the calibration unit 36 is calibrated, which is also referred to as "zeros". In particular, when zeroing the Palpierspitze 50 the calibration unit 36 the coordinates of the origin of the fixed coordinate system 60 be assigned to. Defines the origin calibration unit 42 not the origin of the fixed coordinate system 60 , so may alternatively their position and / or orientation in the space of the Palpierspitze 50 the calibration unit 36 be assigned, if this data is known. Optionally, the coordinates by means of the navigation system 22 be determined if at the origin calibration gauge a marker element analogous to the marker element 38 is arranged. A position of the origin calibration gauge 42 in the room can then, for example, in relation to the detection device 30 be determined.

An alternative approach for zeroing the calibration unit 36 is that these so-called zeros is then performed when the position and / or orientation of the calibration unit 36 that from the navigation system 22 be monitored, for a certain holding time t _stop , for example, for at least 3 to 30 seconds, preferably 5 to 7 seconds, not or hardly change. The assignment of position and / or orientation data of the calibration unit occupying an original calibration position 36 can then be done automatically.

Another variant is that instead of the operation of the switch 56 as actuating element for an operator a foot switch is provided. The navigation system 22 or the data processing unit 24 can be designed and / or programmed such that as a result of the operation of the foot switch or even the switch 46 a calibration signal is generated which initializes the "zeroing".

Another variation of an origin calibration becomes an alternative origin calibration gauge 42a used. This is essentially analogous to the origin calibration theory 42 built, however, is at the closed end of the recording 48 a microswitch 58 Arranged by the Palpierspitze 50 the calibration unit 36 is actuated when a distal end 49 the same in the recording 48 immersed in a defined manner and occupies the origin calibration position. By operating the microswitch 58 can zero the calibration unit 36 be initialized. Using the origin calibration gauge 42a an actuator on the calibration unit is not necessarily required to initiate the origin calibration process.

Is the calibration unit equipped with at least one inertial sensor 36 calibrated in the original coordinate system, then this can be used in a next step, the referencing units 14 and or 18 in this coordinate system 60 to reference. For this example, the top 50 the calibration unit 36 to the referencing units 14 and 16 introduced or in a to the distal end 49 the calibration unit 36 corresponding admission 62 be introduced at least in part. Thus, at least for one point and / or one direction, a clear calibration position can be set between the calibration unit 36 and the referencing units 14 respectively 18 pretend. The pictures 62 may also be part of a calibration gauge attached to the referencing unit 14 respectively 18 is arranged. Conversely, such a calibration gauge can also be attached to the calibration unit 36 be provided, so that, for example, a part of the referencing 14 respectively 18 in a vorgese for it, not shown in the figures recording on the calibration 36 can be introduced.

The referencing or calibration of the referencing units 14 and 18 can be initialized in particular by a microswitch, for example, at each of the referencing units 14 respectively 18 is arranged and in the calibration position, for example, from the Palpierspitze 50 the calibration unit 36 is pressed. Alternatively, as in the case of the origin calibration, a referencing of the referencing units 14 respectively 18 take place when there is a relative position between the calibration unit 36 and the referencing units 14 respectively 18 for a certain, predetermined holding time t _stop does not change. The _hold time t _stop can be specified, for example, in a time window of 3 seconds to 30 seconds. So take the calibration unit 36 and the referencing unit to be referenced 14 respectively 18 for a certain time, the calibration position, so the known position and / or orientation data of the calibration 36 through the navigation system 22 the respective referencing unit 14 respectively 18 be assigned. Position and / or orientation of the referencing unit 14 respectively 18 are then in the fixed coordinate system 60 known.

To errors in a measurement of movements or trajectories of the referencing units 14 and 18 In the room, the navigation system can avoid 22 in particular be designed so that a detection of the trajectories of the referencing 14 and 18 , So a so-called navigation operation, can only be activated if the positions of the referencing units 14 and 18 or possibly further referencing units in the coordinate system 60 were referenced. The release for the navigation operation is carried out by the navigation system 22 especially automatically. Furthermore, the navigation system 22 designed and optionally programmed so that the navigation _{operation is} limited in time to an operating time t _operation or can be limited. Due to the drift of the inertial sensors, the navigation _operation may be limited to an operation time t _operation in a range of 1 second to 60 minutes. Preferably, the operating time t _{operation is} limited to 5 minutes. The operating time t _operation can in particular be monitored by an operating time monitoring device, which is part of the navigation system 22 or their data processing unit 24 can be. After the operating time t _{operation has} elapsed, an audible and / or visual warning signal can sound, so that an operator of the navigation system 20 is pointed to the end of the navigation operation. Optionally, the navigation operation by the navigation system 22 also be ended automatically.

After expiry of the operating time t _operation , a new referencing of the reference units equipped with inertial sensors is possible 14 and 18 and optionally also the calibration unit 36 required. As described above, the calibration unit is first used for this purpose 36 by means of the origin calibration gauge 42 referenced and then proceeded as described further.

The origin calibration of the calibration unit 36 is schematic in 5 shown. At time t ₀ , the calibration unit 36 by means of the origin calibration gauge 42 in the fixed coordinate system 60 calibrated. Thereafter, by means of the calibration unit 36 one referencing unit after the other in the fixed coordinate system 60 be referenced. The operating time t _{operations of} the navigation operation begins, for example, at time t ₁ , to which all referencing units 14 and 18 were referenced. After expiration of the operating time t _operation , ie at time t ₂ , the measurement inaccuracies are so large by a drifting away of the inertial sensors that no more meaningful, that is sufficiently precise, navigation operation is more feasible. The calibration unit 36 must therefore be recalibrated, for example at time t _N.

In cases where homing in a fixed coordinate system is not required, reference may be made to the step of referencing the calibration unit 36 waived who the. Instead, it is sufficient, the calibration unit 36 and the referencing units 14 respectively 18 each in a calibration position to bring. Optionally, this can be done on the referencing units 14 and 18 calibrating gauges 64 respectively 66 be arranged, which has a geometrically one-to-one relative position between the calibration unit and the Referenzierungseinheiten 14 respectively 18 to ensure. For example, the calibration gauges 64 and 66 similar to the origin calibration gauge 42 Recordings 62 in which a distal end of the calibration unit 36 with the Palpierspitze 50 is introductory.

A so-called relative referencing can then be performed as follows. When the calibration unit 36 and the referencing unit 14 assume the calibration position in a defined manner, in particular a calibration signal can be generated. This can be initialized by an operator, for example by operating a hand or foot switch. The calibration signal can also be generated automatically when the calibration position for a certain time t _{stop is} taken. Alternatively, an actuating element can also be actuated automatically and generate a calibration signal when the calibration unit 36 and the referencing unit 14 take the calibration position. For example, the referencing unit 14 be equipped with a microswitch, which, much like the microswitch 58 through the Palpierspitze 50 is operable. Of course, the microswitch could also be on the calibration unit 36 be arranged and by an associated projection on the Referenzierungseinheit 14 be operated in the calibration position. With the inertial sensors of the referencing unit 14 and the calibration unit 36 forces acting on both units are determined. The calibration allows the force measurement values to be set to 0 at time t _{0 of} the calibration for both inertial sensors. Thus, as it were, a coordinate origin of a non-stationary coordinate system is defined at time t ₀ . Below, all measurements of location and / or orientation of the referencing unit 14 and the calibration unit 36 be determined in relation to the calibration position. In particular, further referencing units, for example the referencing unit 18 , relative to the calibration position of the calibration unit 36 and the referencing unit 14 be referenced by the calibration unit 36 in a calibration position relative to the referencing unit 18 is brought and this then the position and / or orientation of the calibration 36 assigned to the non-stationary coordinate system. If all referencing units have been referenced in the manner described above, as described above, the operating time t _{operations runs} during which a navigation operation is possible, that is to say the referencing units 14 and 18 can move freely and their trajectories through the navigation system 22 be recorded. Further, during the navigation operation with the calibration unit 36 also arbitrary points in the room are palpated, depending on whether an absolute or relative referencing has been made relative to a stationary or non-stationary coordinate system.

The procedure for relative referencing in a non-stationary coordinate system is shown schematically in FIG 7 represented in the diagram, the forces acting on the inertial sensors 68 and the referencing unit 14 acting forces 70 are shown as examples and time-dependent.

In a further variant of the described method, a relative referencing of the referencing units 14 and 18 also be done as follows. At time t ₀ are by the navigation system 22 both referencing units 14 and 18 "zeroed", that is to say at time t ₀ , that of the inertial sensors of the referencing units 14 respectively 18 generated signals to zero. To relative movements of the two homing units 14 and 18 can be determined relative to each other in the desired manner, the two Referenzierungseinheiten 14 and 18 with the calibration unit 36 be palpated in succession, or in other words, the calibration unit 36 is successively in each case in a calibration position with the referencing unit 14 and with the referencing unit 18 brought. Used in the first calibration position, for example in the calibration position of the calibration unit 36 relative to the referencing unit 14 the calibration unit 36 Position and / or orientation of the referencing unit 14 assigned, so can a distance between the two homing units 14 and 18 be easily determined by the fact that the calibration unit 36 next in a calibration position relative to the referencing unit 18 is moved. Subsequently, any position and / or orientation changes of the referencing units 14 and 18 by means of the navigation system 22 recorded and issued. After expiration of the operating time t _{establishments} can be the referencing unit 14 and 18 for example, be automatically zeroed again. That is, the referencing unit 14 For example, again a measured value 0 is assigned and the referencing unit 18 a measured value which corresponds to the difference at the end of the operating time t _operations . This leaves the relative positions of the referencing units 14 and 18 receive each other, a repeated distance determination by means of the calibration unit 36 is not necessary then.

The procedure for relative referencing in the latter case is in 6 shown schematically, the time-dependent power curves 70 and 72 to the inertial sensors of the referencing units 14 respectively 18 correspond to acting forces by way of example.

Depending on whether with the referencing units 14 respectively 18 Positions and / or orientations in a coordinate system to be determined, a corresponding referencing is required. For this example, the referencing units 14 and 18 be equipped with so-called Kalibrierlehren which geometrically on a part or portion of the calibration unit 36 to define a clear orientation, position or position, including orientation. This also applies analogously to the origin calibration described above, so that the calibration gauges described below could in principle also serve as origin calibration gauges. It should also be noted that the calibration gauges, as described below by way of example, also on the calibration unit 36 be arranged and cut with appropriate from or parts of the referencing 14 respectively 18 can be brought into engagement.

To specify an axis, for example, a calibration gauge 100 serve, which is formed substantially cuboid and in a side surface extending parallel to side edges wedge-shaped groove 102 having. A cylindrical section of the calibration unit can be attached to the groove 102 be created and so an axis 104 define. Schematically is the calibration gauge 100 in the 8th and 9 shown.

An alternative calibration gauge 110 to define an axis 112 is in 10 shown. The axis 112 is defined by a through hole 114 through the essentially cuboid body of the calibration gauge 110 , Optionally, the calibration gauge 110 also with a cuboid projection 116 be provided, which from a side surface 118 protrudes and also defines an axis. The lead 116 but can also serve as a universal adapter to the calibration gauge 110 with one of the referencing units 14 respectively 18 or the calibration unit 36 connect to.

With the in the 11 and 12 schematically illustrated calibration gauge 120 can both be an axis 122 as well as pretend a point in space. An essentially cuboid basic body of the calibration gauge 120 is for this purpose with a blind hole 124 provided, their bottom 126 defines a stop, for example, the Palpierspitze 50 the calibration unit 36 ,

Also a point and an axis for an instrument navigation can be with the in the 13 and 14 shown calibration gauge 130 perform essentially the calibration 100 corresponds, so also a wedge-shaped groove 132 in a side surface parallel to side edges of the cuboid body of the calibration gauge 130 having. In addition, there is a stop 134 provided by the through the groove 132 defined axis 136 is enforced. The stop 134 For example, serves as a stop for the Palpierspitze 50 the calibration unit 36 to define a point.

For referencing planes in a coordinate system, those in the 15 and 16 respectively 17 and 18 schematically illustrated calibration gauges 140 and 150 be used. They can also be used as a sawing jig. The calibration gauge 140 comprises a substantially cuboidal body having in a side surface a flat rectangular groove 142 which optionally has one stop at one end 144 can be closed. A saw blade, for example, in the groove 142 be inserted and guided in this. Will the calibration gauge 140 brought in a desired manner in a stationary or non-stationary coordinate system in a desired position, the Kalibrierlehre 140 can also be used directly as a saw jig, for example, to perform a cut on the tibia or femur of a patient.

The calibration gauge 150 is to define a plane with a slot 152 provided, which may be formed in particular as a continuous slot or as a slot in the form of a blind hole. The slot 152 in particular can also serve as a guide for a saw blade. An optional from a side surface of the calibration gauge 150 protruding cuboid projection can ter as Adap 154 for connecting the calibration gauge 150 with one of the referencing units 14 respectively 18 or the calibration unit 36 serve.

In the 19 schematically illustrated calibration gauge 160 consists essentially of a cuboid base body with one of a side surface 164 vertically protruding adapter 162 , which is not rotationally symmetrical, to prevent rotation in the connection of the Kalibrierlehre 160 with one of the referencing units 14 respectively 18 or the calibration unit 36 define. Other side surfaces 166 and 168 the calibration unit 160 are used to define levels, for example for saw cuts to be carried out. In addition, the side surfaces 166 and 168 be provided with lateral limit stops for additional guidance of a saw blade.

An example of two calibration gauges that can be brought together in a one-to-one calibration position 170 and 180 is in 20 shown. The calibration gauge 180 has a cuboid recording for this purpose 184 in which a part of the calibration gauge 170 is positively inserted. Both the calibration gauge 170 as well as the calibration gauge 180 are each provided with a parallelepiped projection which extends perpendicularly from each side surface away and an adapter 172 respectively 182 for connection to a referencing unit 14 respectively 18 or the calibration unit 36 forms. Of course, it would also be conceivable, one of the two Kalibrierlehren 170 or 180 to be used as the origin calibration gauge.

The in the 8th to 20 Calibration gauges shown are only to be understood as examples in order to perform one-dimensional referencing, ie directional referencing, two-dimensional referencing, for example plane referencing, and three-dimensional referencing, in particular point-directional referencing. Of course, for a high-precision navigation operation, the exact dimensions of the calibration gauges and their equipment prior to use in conjunction with a navigation system 22 be determined in advance. For example, a relative position between the Palpierspitze 50 and the calibration gauge attached to the calibration unit 36 is arranged to be determined with high precision. From one by means of the navigation system 22 determined position and / or orientation of the calibration can thus always high-precision also a position and / or orientation of the Palpierspitze 50 determine.

Claims (36)

Surgical Calibration Device ( 10 ) for calibrating a position and / or an orientation in the space of at least one surgical, with at least one inertial sensor ( 34 ) ( 14 . 18 ) of a surgical navigation system ( 22 ) relative to a coordinate system of the room, comprising: - a navigation system ( 22 ) with a data processing unit ( 24 ), whereby the navigation system ( 22 ) and the data processing unit ( 24 ) are designed and programmed such that position and / or orientation data of the referencing unit ( 14 . 18 ) are determinable relative to the coordinate system, - a calibration unit ( 36 ), whose position and / or orientation data related to the coordinate system from the navigation system ( 22 ) are determinable, the calibration unit ( 36 ) and the at least one referencing unit ( 14 . 18 ) relative to each other in a one-to-one calibration position can be brought, in which the calibration unit ( 36 ) and the at least one referencing unit ( 14 . 18 ) each occupy a relative to each other defined calibration position and / or orientation, wherein the navigation system ( 22 ) and the data processing unit ( 24 ) are further designed and programmed such that position and / or orientation data of the calibration unit ( 36 ) relative to the coordinate system, it is possible to determine that calibration position and / or orientation data of the referencing unit ( 14 . 18 ) in the calibration position on the basis of the calibration position and / or orientation data of the calibration unit ( 36 ) are calculable and that for the at least one referencing unit ( 14 . 18 ) calibration position and / or orientation data in the calibration position of the at least one referencing unit ( 14 . 18 ) are assignable. Surgical calibration device according to claim 1, characterized in that the navigation system ( 22 ) and the data processing unit ( 24 ) are further designed and programmed in such a way that a non-stationary coordinate system can be predetermined as the coordinate system and that a coordinate origin of the non-stationary coordinate system can be determined by the calibration position and / or orientation data of the at least one referencing unit ( 14 . 18 ) or the calibration unit ( 36 ) can be specified in the calibration position. Surgical calibration device according to claim 1, characterized in that the navigation system ( 22 ) and the data processing unit ( 24 ) are further configured and programmed such that at least two referencing units ( 14 . 18 ) can be calibrated, in which a non-stationary coordinate system can be specified as the coordinate system, and in that a coordinate origin of the non-stationary coordinate system can be determined by one of the at least two referencing units ( 14 . 18 ) can be specified. Surgical calibration device according to claim 1, characterized in that an origin calibration gauge ( 42 ) and that the navigation system ( 22 ) and the data processing unit ( 24 ) are further designed and programmed in such a way that by the origin calibration calibration ( 42 ) defined and fixed in space coordinate origin of an absolute coordinate system ( 60 ) can be specified that the calibration unit ( 36 ) in an original calibration position relative to the original calibration gauge ( 42 ), in which the calibration unit ( 36 ) is positioned in a defined relationship to the fixed coordinate origin, and the origin position and / or orientation data of the calibration unit ( 36 ) in the original calibration position relative to the fixed coordinate origin of the calibration unit ( 36 ) are assignable. Surgical calibration device according to one of the preceding claims, characterized in that a calibration signal generating device is provided for generating a calibration signal when the calibration unit ( 36 ) and the at least one referencing unit ( 14 . 18 ) assume the calibration position. Surgical calibration device according to claim 5, characterized in that the calibration signal generating device is designed such that the calibration signal is generated only after a holding time t _H , during which the calibration unit ( 36 ) and the at least one referencing unit ( 14 . 18 ) assume the calibration position without or substantially without relative movement. Surgical calibration device according to one of claims 5 or 6, characterized in that at least one actuating element ( 56 . 58 ) which is operable in the calibration position, and in that the calibration signal is generated by the calibration signal generating device only during or as a result of actuation of the at least one actuating element ( 56 . 58 ) is producible. Surgical calibration device according to claim 7, characterized in that the at least one actuating element ( 56 . 58 ) is arranged such that it passes through the calibration unit ( 36 ) and / or the at least one referencing unit ( 14 . 18 ) is operable. Surgical calibration device according to one of claims 7 or 8, characterized in that the at least one actuating element ( 56 . 58 ) comprises a button or a footswitch. Surgical calibration device according to one of claims 7 to 9, characterized in that the at least one actuating element ( 56 . 58 ) at the at least one referencing unit ( 14 . 18 ), on the calibration unit ( 36 ) and / or at the origin calibration gauge ( 42 ) is arranged. Surgical calibration device according to one of claims 5 to 10, characterized in that the navigation system ( 22 ) and the data processing unit ( 24 ) are further designed and programmed such that only after the presence of the calibration signal, the calibration position and / or orientation data of the calibration unit ( 36 ) in the calibration position by means of the navigation system ( 22 ), the calibration position and / or orientation data of the at least one referencing unit ( 14 . 18 ) in the calibration position and that for the at least one referencing unit ( 14 . 18 ) cali brierpositions- and / or orientation data in the calibration position of the at least one referencing unit ( 14 . 18 ) are assignable. Surgical calibration device according to one of the preceding claims, characterized in that an origin calibration signal generating device is provided for generating an origin calibration signal when the calibration unit ( 36 ) assumes the original calibration position. Surgical calibration device according to claim 12, characterized in that the origin calibration _{signal generating} device is designed such that the origin calibration _{signal can be} generated only after a holding time t _{H_Ursprung} , during which the calibration unit ( 36 ) assumes the origin calibration position motionless or substantially motionless. Surgical calibration device according to one of claims 12 or 13, characterized in that an origin calibration actuating element ( 58 ) operable in the original calibration position and that the origin calibration signal is only during or in response to an actuation of the origin calibration actuator ( 58 ) is producible. Surgical calibration device according to claim 14, characterized in that the origin calibration actuation element ( 58 ) is arranged such that it passes through the calibration unit ( 36 ), a referencing unit ( 14 . 18 ) or the origin calibration gauge ( 42 ) is operable. Surgical calibration device according to one of Claims 14 or 15, characterized in that the origin calibration actuating element ( 58 ) comprises a button or a footswitch. Surgical calibration device according to one of claims 12 to 16, characterized in that the navigation system ( 22 ) and the data processing unit ( 24 ) are further configured and programmed such that the origin position and / or orientation data of the calibration unit (only after the presence of the origin calibration signal) ( 36 ) in the original calibration position relative to the fixed coordinate origin of the calibration unit ( 36 ) are assignable. Surgical calibration device according to one of the preceding claims, characterized in that the navigation system ( 22 ) and the data processing unit ( 24 ) are further configured and programmed such that a navigation operation of the navigation system ( 22 ) for tracking any movements of the at least one referencing unit ( 14 . 18 ) is only then released, if all the referencing units required for navigation operation ( 14 . 18 ) with the calibration unit ( 36 ) were calibrated relative to a common coordinate system. Surgical calibration device according to claim 18, characterized in that the navigation system ( 22 ) comprises a Betriebszeitvorgabeein unit, with which a navigation operation on a vorgebare operating time t _{operation is} limited. Surgical calibration device according to claim 19, characterized in that the navigation system ( 22 ) and the data processing unit ( 24 ) are further designed and programmed such that the operating time t _operation predeterminable by the operating time specification unit automatically starts to run when all the referencing units ( 14 . 18 ) with the calibration unit ( 36 ) were calibrated relative to a common coordinate system. Surgical calibration device according to one of claims 19 or 20, characterized in that a warning signal generating device is provided, with which after the operating time t _operation, an optical and / or audible warning signal can be issued and / or with the navigation operation is automatically terminated. Surgical calibration device according to one of claims 19 to 21, characterized in that the navigation system ( 22 ) comprises an operating time monitoring device, with which the operating time t _{operation can be} monitored. Surgical calibration device according to one of claims 19 to 22, characterized in that an operating time limiting device is provided for limiting the operating time t _operation to a maximum time in a range of 1 second to 60 minutes. Surgical calibration device according to one of the preceding claims, characterized in that the calibration unit ( 36 ) at least one inertial sensor ( 34 ). Surgical calibration device according to one of the preceding claims, characterized in that the calibration unit ( 36 ) and the at least one referencing unit ( 14 . 18 ) each comprise at least one transmission unit for transmitting measured values or changes in the position and / or orientation data of the calibration unit ( 36 ) and the at least one referencing unit ( 14 . 18 ) to the navigation system ( 22 ) or to a detection device ( 30 ) of the same. Surgical calibration device according to one of the preceding claims, characterized in that the navigation system ( 22 ) for determining the position and / or orientation data of the calibration unit ( 36 ) and the at least one referencing unit ( 14 . 18 ) comprises an evaluation unit, which is designed such that by means of the at least one inertial sensor ( 34 absolute position and / or orientation data for the calibration unit ( 36 ) and / or the at least one referencing unit ( 14 . 18 ) are calculable. Surgical calibration device according to claim 26, characterized in that the evaluation unit is designed and / or programmed such that from the measured acceleration values position and / or orientation change data of the calibration unit ( 36 ) and the at least one referencing unit ( 14 . 18 ) are calculable with respect to the coordinate system and that from the calculated position and / or orientation change data absolute position and / or orientation data of the calibration unit ( 36 ) and the at least one referencing unit ( 14 . 18 ) are calculable relative to the coordinate system. Surgical calibration device according to one of the preceding claims, characterized in that an inertial sensor unit comprising the at least one inertial sensor ( 34 ), which comprises at least six acceleration sensors with which the calibration unit ( 36 ) and / or the at least one referencing unit ( 14 . 18 ) acting accelerations in three mutually linearly independent directions and by three mutually linearly independent axes of rotation are measured time-dependent. Surgical calibration device according to one of the preceding claims, characterized in that at least one calibration gauge ( 64 ; 66 ; 100 ; 110 ; 120 ; 130 ; 140 ; 150 ; 160 ; 170 ; 180 ) is provided, which at least one calibration recording ( 62 ) for at least partially recording the calibration unit ( 36 ) in the calibration position. Surgical calibration device according to claim 29, characterized in that the at least one calibration gauge ( 64 ; 66 ; 100 ; 110 ; 120 ; 130 ; 140 ; 150 ; 160 ; 170 ; 180 ) at the at least one referencing unit ( 14 . 18 ) is arranged. Surgical calibration device according to one of claims 29 or 30, characterized in that the at least one calibration receptacle ( 62 ) one to a part of the calibration unit ( 36 ) corresponding recess ( 62 ) into which this part of the calibration unit ( 36 ) is positively insertable. Device according to one of claims 29 to 31, characterized in that the at least one calibration gauge ( 64 ; 66 ; 100 ; 110 ; 120 ; 130 ; 140 ; 150 ; 160 ; 170 ; 180 ) a one-, two- or three-dimensional calibration gauge ( 64 ; 66 ; 100 ; 110 ; 120 ; 130 ; 140 ; 150 ; 160 ; 170 ; 180 ) for a position and / or orientation calibration of the at least one referencing unit ( 14 . 18 ) and the calibration unit ( 36 ) is relative to each other. Surgical calibration device according to one of claims 4 to 38, characterized in that the origin calibration gauge ( 42 ) at least one origin calibration recording ( 48 ) for at least partially recording the calibration unit ( 36 ) in the original calibration position. Surgical calibration device according to claim 33, characterized in that the at least one origin calibration recording ( 48 ) one to a part of the calibration unit ( 36 ) corresponding recess ( 48 ) into which the one part of the calibration unit ( 36 ) is positively insertable. Surgical calibration device according to one of Claims 7 to 34, characterized in that the origin calibration actuating element ( 58 ) and / or the actuating element ( 56 ) are manually operated. Surgical calibration device according to Claim 35, characterized in that the origin calibration actuating element ( 58 ) and / or the actuating element ( 56 ) one at the origin calibration gauge ( 42 ) and / or at least one referencing unit ( 14 . 18 ) or on the calibration gauge ( 64 ; 66 ; 100 ; 110 ; 120 ; 130 ; 140 ; 150 ; 160 ; 170 ; 180 ) arranged micro switch ( 56 . 58 ).