DE102019125418B3 - Intraoperative optical imaging method and intraoperative optical imaging system - Google Patents

Abstract

An intraoperative optical imaging method and an intraoperative optical imaging system are made available. The intraoperative optical imaging system is equipped with a nerve stimulator (1) for stimulating at least one brain function in a brain operation field (5); - an optical imaging device (3, 103) for recording images of the brain operation field (5) with and without stimulation of the at least one brain function - a monitoring device (7, 9, 31) for monitoring the position and / or the orientation of the optical imaging device (3, 103) relative to the brain operation field (5); - a determination device (11) for determining a deviation in the position and / or the orientation of the optical imaging device (3, 103) from a desired position and / or a desired orientation and a compensation device (13) for reducing the effects of the determined deviation on the images of the brain operation field (5). While the images are being recorded, the position and / or the orientation of the optical imaging device (3, 103) relative to the brain operation field (5) is monitored. If a deviation in the recorded position and / or the recorded orientation from the target position and / or the target orientation is determined as part of the monitoring, measures are taken to reduce the effect of the determined deviation on the images of the brain operation field (5).

Description

The present invention relates to an intraoperative optical imaging method for finding brain tissue areas connected to at least one stimulated brain function in a brain operation field. In addition, the invention relates to an intraoperative optical imaging system with the aid of which brain tissue areas that are connected to at least one stimulated brain function can be found in a brain operation field.

When resecting brain tumors, the surgeon faces the challenge of removing the tumor as completely as possible and thereby damaging as little healthy tissue as possible. In particular, brain areas of particular importance should be spared, for example the visual cortex responsible for seeing or the sensory cortex responsible for the sense of touch.

Methods such as functional magnetic resonance tomography can be used to determine the position of the tumor and functional brain tissue areas preoperatively. This makes it possible to determine preoperatively the areas of the brain tissue to be protected and to prepare for a resection of the brain tumor that is as gentle as possible. When the skull is opened (trepanation), however, the brain tissue can shift, the so-called brain shift, which is why it is necessary to verify the position of the functional brain tissue areas within the exposed brain tissue. Such a verification can take place by means of an intraoperative mapping of the functional brain tissue areas (so-called brain mapping). The mapping can take place, for example, on the measurement of electrical signals on the surface of the brain tissue, which are triggered, for example, by peripheral stimulation on the extremities.

As a contactless alternative to mapping using electrical signals, there is what is known as intraoperative optical imaging (IOI for short), in which the change in perfusion, i.e. the blood flow, or the change in the oxygen content in the blood occurs when changing between stimulation and non-stimulation of certain brain functions is determined. The perfusion and / or the oxygen content of the blood can be measured via a change in the spectral properties of the reflection image of the brain tissue in the area of the trephination. Methods for intraoperative optical imaging are for example in M. Oelschlägel et al. "Intraoperative identification of somatosensory brain areas using optical imaging and standard RGB camera equipment - a feasibility study", Current Directions in Biomedical Engineering 2015; 1: 265-269 , in K. Sato "intraoperative intrinsic optical imaging of human somatosensory cortex during neurosurgical operations" in Neurophotonix 4 (3), 031205 (July to September 2017) as in SB Sobottka "Intraoperative optical imaging of intrinsic signals: a reliable method for visualizing stimulated functional brain areas during surgery" in J. Neurosurg. 119 (2013) , Pages 853 to 863.

Devices for intraoperative optical imaging are also integrated into surgical microscopes. Such surgical microscopes are for example in DE 2008 040 807 A1 , U.S. 5,215,095 A , US 9 095 255 B2 , US 9 801 549 B2 and US 2009/0 234 236 A1 described. In doing so, use is made of the fact that surgical microscopes generally have a camera for documenting the course of the operation, which can also be used to record the signal for intraoperative optical imaging. On the basis of the data obtained with the intraoperative optical imaging, a so-called “activity map” is then created, ie a map of the exposed brain tissue in which areas of the brain tissue associated with a stimulated brain function are displayed.

To create the map, images of the brain operation field are recorded during a recording period, phases in which a certain brain function is stimulated alternating with phases without stimulation during the recording period. In the in M. Oelschlägel et al. "Intraoperative identification of somato-sensory brain areas using optical imaging and standard RGB camera equipment - a feasibility study", Current Directions in Biomedical Engineering 2015; 1: 265-269 , described method, the intraoperative optical imaging takes place, for example, over a period of 9 minutes, 30-second stimulation phases with 30-second rest phases, ie

Phases without stimulation, alternate. The measurement signal, from which the map is finally created, results from the different blood flow to the brain tissue area during the stimulation and during the rest phases and / or from the different oxygen content of the blood during the stimulation phases and the rest phases.

Compared to mapping using electrical signals, in which electrodes are applied to the surface of the brain tissue, intraoperative optical imaging offers the advantage that the brain tissue does not have to be touched during the measurement. On the other hand, it is not easy to determine a change in perfusion or a change in the oxygen content of the blood by means of optical measurement (and without fluorescence). as the signals to be recorded are weak. For this reason, the measurement is carried out with the aid of intraoperative imaging over a relatively long period of time, for example over the already mentioned 9 minutes with alternating 30-second stimulation phases and 30-second rest phases.

The quality of the localization by means of intraoperative optical imaging depends heavily on the quality of the images from the brain operation field. A deterioration in the quality of the recordings leads to an inaccurate localization of the brain tissue areas connected to the stimulated brain function and, in the worst case, to the fact that the localization is so inaccurate that a repetition of the intraoperative optical imaging process is necessary.

The object of the present invention is to provide an intraoperative optical imaging method and an intraoperative optical imaging system with which the quality of the recordings of the brain operation field can be improved.

This object is achieved by an intraoperative optical imaging method according to claim 1 and an intraoperative optical imaging system according to claim 12. The dependent claims contain advantageous developments of the invention.

According to a first aspect of the invention, an intraoperative optical imaging method is provided for finding brain tissue areas connected to at least one stimulated brain function in a brain operation field. In the method, images of the brain operation field with and without stimulation of the at least one brain function are recorded with the aid of an optical imaging device, which can be, for example, a surgical microscope or part of a surgical microscope. The recorded images are evaluated by means of an algorithm in order to find the areas of brain tissue associated with the stimulated brain function. In the method according to the invention, the position and / or the orientation of the optical imaging device relative to the brain operation field is monitored while the images are being recorded. If a deviation of the recorded position and / or the recorded orientation from a target position and / or a target orientation is determined in the course of the monitoring, measures are taken to reduce the effect of the determined deviation on the images of the brain operation field. A deviation of the detected position and / or the detected orientation from the desired position and / or the desired orientation should be understood to mean a deviation that is greater than the non-significant deviation resulting from the measurement noise. In particular, a threshold value for the difference between the detected position and / or the detected orientation on the one hand and the target position and / or the target orientation on the other hand can be specified, which must be exceeded so that the difference is viewed as a deviation.

As already described at the beginning, the localization of brain tissue areas connected to a stimulated brain function with the help of intraoperative optical imaging requires relatively long recordings of the brain operation field in order to be able to extract the information necessary for the localization from the recorded images. For this reason, stands, by which the optical imaging device is held, are fixed during the intraoperative imaging in order to avoid an undesired change in position. The fixation can either be done by braking the tripod by applying a frictional force inhibiting the movement of the tripod in the area of the tripod joints, or by active fixation in which a counter-torque compensating this moment is applied to the joint for a moment acting on a tripod joint be realized. In the fixed state of the stand, however, external or internal forces can act on the imaging device, which lead to a static or dynamic deviation of the position and / or the orientation of the optical imaging device from its desired position and / or its desired orientation. Static deviations can be caused, for example, by contact of the optical imaging device with another device or by the staff in the operating room leaning against the imaging device. Leaning against the operating table can also lead to static deviations. There can also be displacements in the brain operation area itself, which lead to a static deviation. Dynamic deviations such as oscillations and vibrations can be caused by hitting the optical imaging device, the tripod holding the imaging device or the operating table, by fans or pumps built into the optical imaging device (fan for cooling the illuminating light source, pumps for evacuating one placed around the optical imaging device Drapes), by operating the imaging device or the operating table, by braking the stand too quickly, by building vibrations, by vibrations caused by personnel walking past, etc. Both decaying vibrations, such as vibrations caused by braking too quickly or hitting a device, or non-decaying vibrations, such as vibrations caused by fans or pumps, for example. The trend towards ever slimmer Constructions and larger ranges of the kinematics of tripods and, due to more integrated functions, increasing total masses of the optical imaging devices with a simultaneous increase in the working distances of the optical imaging devices from the surgical field and the increasing enlargement of the imaging scales exacerbate the problem mentioned.

Any deviation occurring during the intraoperative optical imaging process in the position and / or the orientation of the optical imaging device relative to the brain operation area from its target position and / or its target orientation relative to the brain operation area compromises the images recorded during the intraoperative optical imaging process, which are typically frames Videos are. The associated deterioration in the quality of the localization of the brain tissue areas connected to the stimulated brain function leads, in the worst case, to the fact that the localization of the stimulated brain tissue areas is unusable, so that the intraoperative optical imaging process has to be repeated in order to localize the brain tissue areas connected to the stimulated brain function to make again. The associated extension of an operation is not only expensive, it is also critical for the patient, since an extension of the duration of the operation can lead the patient into a life-threatening condition. The repetition of an intraoperative optical imaging process should therefore be avoided as far as possible.

Due to the monitoring of the position and / or the orientation of the optical imaging device relative to the brain operation field as part of the method according to the invention, a deviation of the position and / or the orientation from a target position and / or a target orientation can be determined at an early stage and measures to reduce the effect of the determined deviation can be taken on the images of the brain operation field. As the simplest measure to reduce the effect of the determined deviation on the images of the brain operation field, the recording of the images can be interrupted until the deviation is no longer present. This measure can be sufficient, in particular, if the deviation is due to a relatively rapidly decaying oscillation, for example an oscillation that was caused by bumping into the optical imaging device or by bumping into the operating table and which quickly decays due to damping. As soon as the oscillation has subsided sufficiently, the recording of the pictures can then be continued. In this way, the resulting vibrations can prevent the image quality from being compromised, and the recording time is only extended by the duration of the interruption, that is to say by the time required for the vibration to decay sufficiently. If the oscillation subsides quickly, it is even possible to work without extending the recording time and to use the reduced number of recorded images due to the brief interruption to localize the brain tissue areas connected to the stimulated brain function. Since these images are all of high quality, the localization can be more precise than if all images, including the images affected by the vibrations, were used for the localization. Alternatively, there is also the possibility of recording the duration of the interruption and adding a corresponding duration to the originally planned duration of the intraoperative optical imaging process, so that the number of images available for localization is not reduced by the interruption. The extension of the intraoperative optical imaging process is particularly useful when a longer interruption is required.

If the determined deviation is not of a subsiding but of permanent nature, the interruption of the recording of the images is maintained until the determined deviation is compensated. A deviation of a permanent nature should be assumed here if there is a static deviation, for example because it is based on a permanent displacement of the optical imaging device or a permanent displacement of the brain operation field, or if there is a decaying deviation whose decay time is too long to cope with the To continue taking the pictures, wait until the deviation has subsided. In this variant, the interruption of the recording gives the personal operating room the opportunity to compensate for the determined deviation by suitable measures without compromising the recorded images. In order to support the staff in the operating room in compensating for the determined deviation, the deviation can continue to be recorded continuously during the interruption and shown on a display. In this way, the staff in the operating room receives immediate feedback as to whether the measures taken are suitable to compensate for the deviation or whether it may even worsen the deviation. A reduction in the deviation in response to the measure taken shows that the measure has the desired effect.

In a particularly advantageous embodiment of the invention, the position and / or the orientation of the optical imaging device relative to the brain operation field is or are motorized driven changeable. A motor-driven stand, to which the optical imaging device is attached, or a motor-driven operating table can serve as a means for motor-driven changing of the position and / or the orientation of the optical imaging device relative to the brain operation field. The determined deviation can then be compensated for by means of a control or regulating unit which acts on the motors of the drive and which, on the basis of the determined deviation, outputs control signals to the motors to compensate for the determined deviation. In this way, the compensation of the determined deviation can take place fully automatically, so that the staff in the operating room can be relieved. In particular, this embodiment is also suitable for compensating for deviations determined in the form of oscillations and vibrations. For this purpose, for example, a tripod arrangement can be used, as shown in DE 10 2007 034 286 A1 is described.

Instead of changing the position and / or the orientation of the optical imaging device relative to the brain operation field in a motor-driven manner, there is also the possibility of using optical elements of the optical imaging device to compensate for the determined deviation. Optical elements with which a displacement along the optical axis of the optical imaging device can be compensated are optical elements with adjustable refractive power. Compensation for a movement along the optical axis with the aid of such optical elements is for example in DE 10 2011 053 630 A1 described. A lateral image offset caused by the determined deviation, on the other hand, can be compensated for by adjustable optical wedges. The compensation of a lateral image offset by means of adjustable optical wedges is for example in DE 10 2011 054 087 A1 described. On the DE 10 2011 053 630 A1 and the DE 10 2011 054 087 A1 reference is made to a possible implementation of the compensation of the determined deviation by means of an optical element of the optical imaging device.

The determined deviation can alternatively also be compensated for by means of a digital image processing method. In the digital image processing method, an image transformation is then calculated on the basis of the determined deviation, with which the determined deviation can be compensated for in the respective image. For this purpose, for example, an image can be used as a reference image and the transformation can be determined by means of a rigid registration method.

If the calculated deviation is compensated automatically by means of a motor-driven stand and / or a motor-driven operating table, by means of adjustable optical elements or by means of a digital image processing method, there is no need to interrupt the recording of the images if the automated compensation can take place so quickly that no such serious effects on the recorded images are to be expected that the intraoperative optical imaging is noticeably impaired.

To detect the position and / or the orientation of the optical imaging device relative to the brain operation field, a navigation system can be used. The sensors necessary for the navigation can, in some design variants, be fully or partially integrated into the operating table or into the optical imaging device. Alternatively, the position and / or the orientation of the optical imaging device relative to the brain operation field can also be recorded with the aid of digital image processing using recorded images, in particular using recorded stereoscopic images. As with the compensation of the determined deviation by means of a digital image processing method, a rigid image registration can be used. Additionally or alternatively, methods for topology comparison or for determining an optical flow can also be used. In a further alternative, in order to detect the position and / or the orientation of the optical imaging device relative to the brain operation field, the topography of the brain operation field relative to the optical imaging device can be determined. The topography can be determined, for example, with depth sensors integrated in the imaging device or via structured lighting and contains information about the distances between the individual areas of the brain operation field from the optical imaging device, which in turn provides information on the position and / or orientation of the optical imaging device relative included to the brain operation field.

• - einen Nervenstimulator zur Stimulation wenigstens einer Gehirnfunktion in einem Gehirnoperationsfeld;
• - eine optische Abbildungsvorrichtung zum Aufnehmen von Bildern des Gehirnoperationsfeldes mit und ohne Stimulation der wenigstens einen Gehirnfunktion;
• - eine Überwachungseinrichtung zum Überwachen der Lage und/oder der Orientierung der optischen Abbildungsvorrichtung relativ zu dem Gehi rnoperationsfeld;
• - eine Ermittlungseinrichtung zum Ermitteln einer Abweichung in der Lage und/oder der Orientierung der optischen Abbildungsvorrichtung von einer Solllage und/oder einer Sollorientierung und
• - eine Ausgleichseinrichtung zum Reduzieren der Auswirkung der ermittelten Abweichung auf die Bilder des Gehirnoperationsfeldes.

According to a second aspect of the present invention, an intraoperative optical imaging system is also provided. This includes

• a nerve stimulator for stimulating at least one brain function in a brain operation field;
• - An optical imaging device for recording images of the brain operation field with and without stimulation of the at least one brain function;
• a monitoring device for monitoring the position and / or the orientation of the optical imaging device relative to the auditory surgical field;
• a determination device for determining a deviation in the position and / or the orientation of the optical imaging device from a desired position and / or a desired orientation and
• a compensation device for reducing the effect of the determined deviation on the images of the brain operation field.

The optical imaging device can in particular be a surgical microscope or part of a surgical microscope. The monitoring device and / or the determination device and / or the compensation device can be integrated into the optical imaging device, for example into a surgical microscope. Alternatively, there is also the possibility that the monitoring device and / or the determination device and / or the compensation device are separate units from the optical imaging device, but which are connected to one another in order to jointly carry out the method according to the invention, or are integrated into a joint unit. With the intraoperative optical imaging system according to the invention, the method according to the invention for intraoperative optical imaging can thus be carried out, so that the properties and advantages mentioned with reference to the method according to the invention for intraoperative optical imaging can be realized with the intraoperative optical imaging device. Reference is therefore made to the properties and advantages described above with reference to the method according to the invention for intraoperative optical imaging in order to avoid repetitions.

To detect the position and / or the orientation of the optical imaging device relative to the brain operation field, the intraoperative optical imaging system according to the invention can include a navigation system. The sensor system of the navigation system can be integrated into the optical imaging system, integrated into the operating table, or designed as a unit separate from both the optical imaging system and the operating table. The use of a navigation system makes it possible to fall back on a system that is often already present in the operating room.

Instead of a navigation system, digital image processing software can be used to record the position and / or orientation of the optical imaging device relative to the brain operation field, which records the position and / or the orientation using recorded images, in particular using recorded stereoscopic images. The image processing software can contain an algorithm for rigid image registration, an algorithm for topography comparison or an algorithm for determining an optical flow. Such an intraoperative optical imaging system can also be used where a navigation system is not available or not desired.

In a further alternative embodiment of the intraoperative optical imaging system, the monitoring device for detecting the position and / or the orientation of the optical imaging device relative to the brain operation field comprises at least one depth sensor. With the depth sensor, the topography of the brain operation field relative to the optical imaging device can be determined, which contains information about the position and / or the orientation of the optical imaging device relative to the brain operation field.

• - ein motorisch angetriebenes Stativ, an dem die optische Abbildungsvorrichtung befestigt ist;
• - einen motorisch angetriebenen Operationstisch;
• - wenigstens ein bewegliches optisches Element der optischen Abbildungsvorrichtung oder
• - ein digitales Bildverarbeitungsmodul, welches auf der Basis der ermittelten Abweichung eine Bildtransformation berechnet, mit der die ermittelte Abweichung in den aufgenommenen Bildern kompensiert werden kann,

umfassen.In order to be able to compensate for a determined deviation in the position and / or the orientation of the optical imaging device from a desired position and / or a desired orientation, the compensation device can at least

• a motor-driven stand on which the optical imaging device is attached;
• - a motor-driven operating table;
• - At least one movable optical element of the optical imaging device or
• - A digital image processing module which, on the basis of the determined deviation, calculates an image transformation with which the determined deviation in the recorded images can be compensated,

include.

• 1 zeigt ein intraoperatives optisches Abbildungssystem in einer schematischen Darstellung.
• 2 zeigt ein Beispiel für den Aufbau eines Operationsmikroskops in einer schematischen Darstellung.
• 3 zeigt ein Beispiel für eine alternative Ausgestaltung des Operationsm i kroskops.
• 4 zeigt ein Beispiel für den Aufbau eines Statives zum Halten eines Operationsm i kroskops.
• 5 zeigt die Freiheitsgrade des Statives aus 4.
• 6 zeigt anhand eines Flussdiagramms ein Verfahren zum intraoperativen optischen Abbilden, bei dem eine Überwachung der Lage und/oder der Orientierung einer optischen Abbildungsvorrichtung relativ zu einem Gehirnoperationsfeld erfolgt.
• 7 zeigt ein Beispiel für eine alternative Ausgestaltung eines Navigationssystems in einem intraoperativen optischen Abbildungssystem.
• 8 zeigt ein Beispiel für eine weitere alternative Ausgestaltung eines Navigationssystems in einem intraoperativen optischen Abbildungssystem.

Further possible features, properties and advantages of the present invention emerge from the following description of exemplary embodiments with reference to the accompanying figures.

• 1 shows an intraoperative optical imaging system in a schematic representation.
• 2 shows an example of the structure of a surgical microscope in a schematic representation.
• 3 shows an example of an alternative embodiment of the surgical microscope.
• 4th shows an example of the structure of a stand for holding a surgical microscope.
• 5 shows the degrees of freedom of the tripod 4th .
• 6th shows a flowchart of a method for intraoperative optical imaging in which the position and / or orientation of an optical imaging device is monitored relative to a brain operation field.
• 7th shows an example of an alternative embodiment of a navigation system in an intraoperative optical imaging system.
• 8th shows an example of a further alternative embodiment of a navigation system in an intraoperative optical imaging system.

In the following, exemplary embodiments for the intraoperative optical imaging system according to the invention and for the intraoperative optical imaging method according to the invention are described in detail with reference to the accompanying figures for explanatory purposes. They show 1 , 7th and 8th Exemplary embodiments for the intraoperative optical imaging system according to the invention, which are recorded in the manner in which the position and / or orientation data used for monitoring the position and / or the orientation of the optical imaging device relative to the position and / or orientation of the brain operation field differ from each other. 6th shows an exemplary embodiment for the sequence of the method to be carried out with the imaging system. The 2 and 3 show exemplary examples of surgical microscopes that can be used as optical imaging devices, and the 4th and 5 an exemplary example of a motor-driven stand with which a surgical microscope can be held and which serves as a compensation device to reduce the effects of a detected deviation in the position and / or the orientation of the optical imaging device relative to the brain operation field from a target position and / or a target orientation Can be used.

1 shows a first exemplary embodiment for an intraoperative optical imaging system according to the invention. This includes a nerve stimulator 1 , a surgical microscope 3 , 103 , which in the present exemplary embodiment as an optical imaging device for recording images of the brain operation field 5 serves, a monitoring device 7th , 9 , 31 , which in the present exemplary embodiment is a navigation system 31 , Marker 7th and cameras 9 has and for monitoring the position and / or orientation of the surgical microscope 3 , 103 relative to the brain operation field 5 serves, a detection device 11 and a compensator 13 . The investigative facility 11 is configured on the basis of signals from the monitoring device 7th , 9 , 31 are output and the position and / or orientation of the surgical microscope 3 , 103 relative to the brain operation field 5 represent a deviation in the position and / or the orientation of the surgical microscope 3 , 103 to determine from a target position and / or a target orientation. In the present exemplary embodiment, the determination device 11 Signals from the navigation system 31 issued. The compensation device 13 is designed for this purpose when a deviation is determined by the determination device 11 the effects of this deviation in the images of the brain surgery field 5 to reduce.

The nerve stimulator 1 is designed to electrically stimulate nerves. For this purpose it comprises a number of electrodes 15th with the help of which nerves of the peripheral nervous system, such as the median nerve (middle arm nerve), which is responsible for the motor control of the forearm muscles and some finger muscles as well as for the sensitive innervation of the palm and thumb up to the inside of the ring finger, or the trigeminal nerve , which is responsible for the sensitive perception in the face as well as for the motor skills of the face, oral cavity and masticatory muscles, can be electrically stimulated. During the intraoperative optical imaging, stimulation cycles are carried out with the aid of the nerve stimulator, each of which is a phase of stimulating a specific brain function with the aid of the electrodes 15th of the nerve stimulator 1 , called the stimulation phase in the context of this description, and a phase without stimulation, called the resting phase in the context of this description. In the context of intraoperative optical imaging, for example, a number of such stimulation cycles can be strung together so that rest phases and stimulation phases alternate over a certain period of time. For example, stimulation cycles can be used as they are in M. Oelschlägel et al. "Intraoperative identification of somato-sensory brain areas using optical imaging and standard RGB camera equipment - a feasibility study", Current Directions in Biomedical Engineering 2015; 1: 265-269 are described, ie 30-second stimulation phases and 30-second rest phases alternating over nine minutes. However, a person skilled in the art recognizes that more or less than nine stimulation cycles can also be carried out. In addition, the duration of the stimulation phases and the rest phases can differ from that of Oelschlägel et al. used to be 30 seconds. The duration of a stimulation phase does not necessarily have to correspond to the duration of a rest phase.

During the stimulation cycles, a camera is used 17th or a digital image sensor 161A , B of the surgical microscope 3 , 103 (see. 2 and 3 ) Images of the brain operation field 5 recorded. As a result of the stimulation, a change in the blood flow and / or the oxygen content in the blood is brought about in the stimulated areas of the brain tissue, which changes in the resting phases. With suitable lighting, for example in the green and blue wavelength range, the change in blood flow and / or the oxygen content causes a visually perceptible change in the stimulated tissue areas, which is reflected in the images, whereas unstimulated brain tissue areas show no such change. With the help of a detection of the changes occurring during the stimulation cycles, the brain tissue areas associated with the stimulated brain function can thus be determined from the recorded images. The areas of brain tissue identified in this way and connected to the stimulated brain function 19th can in one picture 21st of the brain operation field 5 marked and on a monitor 23 are displayed.

The localization of the brain tissue areas associated with a stimulated brain function on the basis of the images recorded in the context of the intraoperative optical imaging method requires relatively long recordings of the brain surgical field due to the weak optical signal 5 . It is important to note the relative position and the relative orientation of the surgical microscope 3 , 103 in relation to the brain operation field 5 to be maintained as precisely as possible during the entire recording period. The surgical microscope 3 , 103 is usually on a tripod 25th hung, with the help of which a suitable setting of the position and / or the orientation of the surgical microscope 3 , 103 relative to the brain operation field 5 is possible. An unintentional change in a position and / or an orientation of the surgical microscope that has been set once 3 , 103 To avoid this, it is equipped with fixing devices, which are intended to prevent the moving parts of the stand from moving. The fixing device can, for example, be the joints of the stand 25th include frictional brakes. If the joints of the tripod are driven by a motor, the fixing device can also include a control with the aid of which on the tripod 25th or on the surgical microscope 3 , 103 Interfering torques acting on them can be compensated by using the tripod 25th acted upon by suitable compensation torques to compensate for the disturbance torques. You can still use the tripod 25th or the surgical microscope 3 , 103 internal or external forces act, which despite the fixation of the stand joints to a static or dynamic deviation of the position and / or the orientation of the surgical microscope 3 , 103 lead from a once set position and / or orientation. If this happens during the intraoperative optical imaging process, this significantly impairs the determination of the areas of brain tissue associated with the stimulated brain function. In the worst case, the entire intraoperative optical imaging process can become unusable, so that it has to be repeated. However, in the patient's interest, such repetition is undesirable. Static deviations can be avoided by leaning against the surgical microscope 3 , 103 , by contact with the surgical microscope 3 , 103 caused by other devices, etc., dynamic deviations due to vibrations or oscillations, e.g. due to bumping into the device, due to built-in fans or pumps, actuation of control units, building vibrations, etc. Deviations in the position and / or orientation of the surgical microscope 3 , 103 relative to the brain operation field 5 but can not only be caused by an unintentional relocation of the surgical microscope 3 , 103 be brought about, but also by an unintended displacement of the operating table 27 on which the patient is 29 is located.

With the help of the monitoring device 7th , 9 , 31 can determine the position and orientation of the surgical microscope 3 , 103 relative to the brain operation field 5 be monitored. In the present exemplary embodiment, both the surgical microscope 3 , 103 , as well as the brain surgery field 5 with markers 7th provided by the cameras 9 the monitoring device. Look from the cameras 9 detected markers 7th can the navigation system 31 the position and orientation of the surgical microscope 3 , 103 as well as the position and orientation of the brain surgery field 5 determine and from the for the surgical microscope 3 , 103 as well as the brain surgery field 5 determined positions and orientations the position and orientation of the surgical microscope 3 , 103 relative to the brain operation field 5 to calculate. The marker 7th of the brain operation field 5 can be attached to the retractor, for example. A retractor is to be understood as a device with which access to the brain surgery field is to be understood 5 is kept open.

The one from the navigation system 31 calculated position and orientation of the surgical microscope 3 , 103 relative to the brain operation field 5 is sent to the determination device in the form of a suitable signal 11 passed on. The signal can be wired or wireless, for example optically or by radio, to the determination device 11 be transmitted. The investigative facility 11 uses the transmitted signals to check whether the position and orientation of the surgical microscope 3 , 103 relative to the brain operation field 5 nor the the set target position and / or the set target orientation. If the investigator 11 a deviation in the position and / or orientation of the surgical microscope 3 , 103 detected by the target position and / or the target orientation, it sends a signal representing the determined deviation to the compensation device 13 which then takes measures with the help of which the effects of the recorded impairment on the recorded images can be reduced.

If the determined deviation is a decaying deviation, for example a decaying oscillation that has been caused, for example, by an impact, the compensation device can 13 as a measure to reduce the effect of the determined deviation on the images of the brain surgery field 5 perform an interruption of the intraoperative optical imaging process, the interruption being maintained until the oscillation has subsided. If, however, the deviation is not of a dynamic nature, but of a static nature, for example because the impact leads to a displacement of the surgical microscope 3 , 103 relative to the brain operation field, the compensation device takes further measures. Further measures are also necessary if an oscillation does not subside but is stimulated again and again, for example by fans or pumps on the stand 25th . Further measures may also be necessary if the oscillation is decaying, but the decay would take so long that it is not possible to wait until the oscillation has decayed.

In the case of a static deviation or an oscillation that decays too slowly, the deviation can be determined by a compensating static or dynamic change in the position and / or the orientation of the surgical microscope 3 , 103 be compensated. The compensation device 11 in the case of a motorized tripod 25th for example on the motors of the tripod 25th controlling access to the desired new position and / or orientation of the surgical microscope 3 , 103 , with which the detected deviation can be compensated, to be set, so that the target position and / or the target orientation of the surgical microscope 3 , 103 relative to the brain operation field 5 is restored. Alternatively, there is a motorized operating table 27 also the possibility that the compensation device 13 instead of the motors of the tripod 25th on the motors of the operating table 27 acts to restore the target position and / or the target orientation. The intraoperative optical imaging process remains interrupted until the target position and / or target orientation is restored.

In the event of a dynamic deviation, for example an undamped oscillation, the compensation device can 13 the motors of the tripod 25th or the operating table 27 cause a suitable counter-oscillation to be induced, which compensates for the detected dynamic deviation. The generation of such a counter vibration by means of a tripod is, for example, in DE 10 2007 034 286 A1 described. Reference is therefore made to the teaching of this document with regard to the generation of a counter-oscillation. What is carried out for the generation of a counter-oscillation can also be used accordingly if the oscillation which the detection device 11 represents the determined deviation, subsides so slowly that an interruption of the intraoperative optical imaging process until the oscillation has finally subsided is out of the question. In the case of a non-decaying oscillation or an oscillation that decays too slowly, the intraoperative optical imaging process is interrupted only until a suitable counter-oscillation is induced.

Instead of the surgical microscope 3 , 103 or the operating table 27 to relocate yourself, there is also the possibility of only using optical elements in the surgical microscope 3 , 103 to relocate to that of the investigator 11 to compensate determined deviation. This works especially if the determined deviation does not exceed a certain level. In this case, for example, optical elements can be used as they are in DE 10 2011 053 630 A1 and DE 10 2011 054 087 A1 are described. The DE 10 2011 053 630 A1 optical elements with adjustable refractive power, which are suitable for detecting deviations in the position of the surgical microscope 3 , 103 along the optical axis of the surgical microscope 3 , 103 to compensate. Optical elements that are suitable for eliminating deviations in the position of the surgical microscope 3 , 103 to compensate that is perpendicular to the optical axis of the surgical microscope 3 , 103 run, for example the in DE 10 2011 054 087 A1 described optical wedges. The optical elements with adjustable refractive power or optical wedges described in the cited documents are therefore used with regard to suitable optical elements for compensating for the energy generated by the determination device 11 determined deviation.

If the determined deviation is not too great, there is also the option of moving the surgical microscope instead of mechanically 3 , 103 , the operating table 27 or one or several optical elements of the surgical microscope 3 , 103 to compensate for the deviation in the recorded images itself. A determined deviation along the optical axis of the surgical microscope 3 , 103 can for example be compensated for by changing the image scale, a determined deviation perpendicular to the optical axis of the surgical microscope 3 , 103 by shifting the image laterally. Deviations in the orientation can be compensated for by distortions in the images.

Using the following 2 to 5 are exemplary examples of surgical microscopes 3 , 103 and tripods 25th described, which can be used in the context of the intraoperative optical imaging system according to the invention.

2 shows in a schematic representation a possible structure of the surgical microscope 3 how it looks in the arrangement 1 Can be used. 3 shows a possible alternative structure.

This in 3 Operating microscope shown 11 comprises, as essential components, an object field, which in the present exemplary embodiment is the brain operation field 5 is the lens to be turned 105 , which can be designed in particular as an achromatic or apochromatic objective. In the present embodiment there is the objective 105 consisting of two partial lenses cemented together, which form an achromatic objective. The object field 5 is in the focal plane of the lens 105 arranged so that it is away from the lens 105 is mapped to infinity. In other words, one from the object field 5 outgoing divergent bundle of rays 107A , 107B becomes as it passes through the lens 105 into a parallel bundle of rays 109A , 109B converted.

Observer side of the lens 105 is a magnification changer 111 arranged, which can be designed either as a zoom system for stepless change of the magnification factor or as a so-called Galilean changer for stepwise change of the magnification factor, as in the illustrated embodiment. In a zoom system, which is composed, for example, of a lens combination with three lenses, the two lenses on the object side can be shifted in order to vary the magnification factor. In fact, the zoom system can also have more than three lenses, for example four or more lenses, the outer lenses then also being able to be arranged in a fixed manner. In a Galilean changer, on the other hand, there are several fixed lens combinations that represent different magnification factors and can be alternately introduced into the beam path. Both a zoom system and a Galileo changer convert a parallel beam on the object side into a parallel beam on the observer side with a different beam diameter. The magnification changer 111 is already part of the binocular beam path of the surgical microscope in the present exemplary embodiment 11 , ie it has its own lens combination for each stereoscopic partial beam path 109A , 109B of the surgical microscope 11 on. Setting a magnification factor using the magnification changer 111 takes place in the present exemplary embodiment via a motor-driven actuator which, together with the magnification changer 111 Part of a magnification change unit for setting the magnification factor.

To the magnification changer 111 an interface arrangement closes on the observer side 113A , 113B on, via the external devices to the surgical microscope 3 can be connected and the beam splitter prisms in the present exemplary embodiment 115A , 115B includes. In principle, however, other types of beam splitters can also be used, for example partially transparent mirrors. The interfaces 113A , 113B serve in the present exemplary embodiment for decoupling a beam from the beam path of the surgical microscope 3 (Beam splitter prism 115B) or for coupling a beam into the beam path of the surgical microscope 3 (Beam splitter prism 115A) .

The beam splitter prism 115A in the partial beam path 109A is used in the present embodiment to use a display 37 , for example a digital mirror device (DMD) or an LCD display, and associated optics 139 via the beam splitter prism 115A Information or data for a viewer in the partial beam path 109A of the surgical microscope 3 to reflect. In the case of a brain operation, for example, the areas of the brain tissue connected to at least one stimulated brain function can be marked 19th into the one with the surgical microscope 3 obtained image can be reflected. In the other partial beam path 109B is at the interface 113B a camera adapter 119 with a camera attached 17th arranged with an electronic image sensor 123 , for example. With a CCD sensor or a CMOS sensor, is equipped. Using the camera 17th can be an electronic and in particular a digital image of the object field 5 be included. A hyperspectral sensor in which there are not only three spectral channels (for example red, green and blue), but a large number of spectral channels can also be used as the image sensor. In the in 1 intraoperative optical imaging system shown can with the camera 17th the video sequences containing the stimulation images and reference images are recorded.

At the interface 113 a binocular tube closes on the observer side 127 at. This has two tube lenses 129A , 129B on which the respective parallel bundle of rays 109A , 109B on an intermediate image level 131 focus, i.e. the object field 5 on the respective intermediate image level 131A , 131B depict. The ones in the intermediate image levels 131A , 131B The intermediate images located are finally provided by eyepiece lenses 135A , 135B again mapped to infinity, so that a viewer can look at the intermediate image with a relaxed eye. In addition, the binocular tube is made using a mirror system or prisms 133A , 133B an increase in the distance between the two partial beams 109A , 109B to adjust it to the eye relief of the observer. With the mirror system or the prisms 133A , 133B The image is also erected.

The surgical microscope 3 is also equipped with a lighting device with which the object field 5 can be illuminated with broadband illumination light. For this purpose, the lighting device in the present exemplary embodiment has a white light source 141 , for example a halogen lamp or a gas discharge lamp. That from the white light source 141 outgoing light is via a deflecting mirror 143 or a deflecting prism in the direction of the object field 5 steered to illuminate this. Illumination optics are also in the illumination device 145 available, which for a uniform illumination of the entire observed object field 5 cares.

It should be noted that the in 2 Illumination beam path shown is highly schematic and does not necessarily reflect the actual course of the illumination beam path. In principle, the illumination beam path can be designed as so-called oblique illumination, which is shown in the schematic illustration in FIG 2 comes closest. In such an oblique illumination, the beam path runs at a relatively large angle (6 ° or more) to the optical axis of the objective 105 and can, as in 3 shown completely outside the lens 105 run away. Alternatively, however, there is also the possibility of the illumination beam path of the oblique illumination through an edge region of the objective 105 to run through. Another possibility for arranging the illumination beam path is the so-called 0 ° illumination, in which the illumination beam path passes through the lens 105 runs through and between the two partial beam paths 109A , 109B , along the optical axis of the lens 105 towards the object field 17th into the lens 105 is coupled. Finally, there is also the possibility of designing the illumination beam path as what is known as coaxial illumination, in which a first and a second partial illumination beam path are present. The two illumination partial beam paths are parallel to the optical axes of the observation partial beam paths via one or more beam splitters 109A , 109B into the surgical microscope 3 coupled in so that the illumination runs coaxially to the two observation beam paths.

In the in 2 operating microscope shown 3 the lighting can be influenced. E.g. a filter can be introduced into the illumination beam path, which is of the broad spectrum of the white light source 141 only allows a narrow spectral range to pass, for example a spectral range with which fluorescence is in the object field 17th located fluorescent dye can be excited. In order to observe the fluorescence, filters can be inserted into the partial observation beam paths 137A , 137B be introduced, which filter out the spectral range used for fluorescence excitation in order to be able to observe the fluorescence. In the present exemplary embodiment, when recording the stimulation images and the reference images, a filter can be inserted into the illumination beam path, which only allows those wavelength ranges of the illumination light to pass in which a change in blood flow or a change in the oxygen content in the blood generates a particularly clear signal in the observation beam path .

In the in 2 shown exemplary embodiment of the surgical microscope 3 is the lens 105 only from an achromatic lens. However, it is also possible to use an objective lens system made up of several lenses, in particular a so-called varifocal objective, with which the working distance of the surgical microscope can be adjusted 3 , ie the distance between the object-side focal plane and the vertex of the first object-side lens surface of the objective 105 , also called the object focal length, can be varied. The object field arranged in the focal plane is also produced by a varifocal lens 5 Imaged to infinity so that a parallel bundle of rays is present on the observer side.

3 shows an example of a digital surgical microscope 103 in a schematic representation. The main objective of this surgical microscope is different 105 , the magnification changer 111 as well as the lighting system 141 , 143 , 145 not from the in 2 operating microscope shown 3 with optical insight. The difference is that in 3 Operating microscope shown 103 does not include an optical binocular tube. Instead of tube lenses 129A , 129B out 2 includes the surgical microscope 103 out 3 Focusing lenses 149A , 149B with which the binocular observation beam paths 109A , 109B on digital image sensors 161A , 161B be mapped. The digital image sensors 161A , 161B can be, for example, CCD sensors or CMOS sensors. The ones from the image sensors 161A , 161B Captured images are sent digitally to digital displays 163A , 163B sent, which can be designed as LED displays, as LCD displays or as displays based on organic light diodes (OLEDs). The displays 163A , 163B can, as in the present example, ocular lenses 165A , 165B associated with those on the displays 163A , 163B displayed images are mapped to infinity, so that a viewer can look at them with relaxed eyes. The displays 163A , 163B and the eyepiece lenses 165A , 165B can be part of a digital binocular tube, but they can also be part of a head-mounted display (HMD) such as data glasses. In addition, there is the option of displaying the recorded images as stereoscopic images on a large monitor, which can be viewed by the staff in the operating room with suitable 3D glasses. To distinguish between the stereoscopic partial images, when the stereoscopic images are displayed on the monitor, they can be displayed with different polarizations of the light emitted by the monitor. The 3-D glasses then contain switchable polarizers that are switched synchronously with the display of the partial images on the monitor.

The in 1 The intraoperative optical imaging system shown can be the video sequences containing the stimulation images and reference images with at least one of the digital image sensors 161A , 161B be included. In this case, the digital image sensor or the digital image sensors turn off the imaging device 1 represent.

Although in 3 as in 2 just an achromatic lens 105 is shown with a fixed focal length, this can be done in 3 Operating microscope shown 101 like that in 2 operating microscope shown 3 a varioskop lens instead of the objective lens 105 include. Furthermore, in 3 a transmission of the from the image sensors 161A , 161B recorded images to the displays 163A , 163B by means of cables 167A , 167B shown. Instead of being wired, the images can also be sent wirelessly to the displays 163A , 163B transmitted, especially when the displays 163A , 163B Are part of a head mounted display.

In the present exemplary embodiment, the surgical microscope is 3 , 103 on a motorized tripod 25th attached. By entering navigation data, the surgical microscope 3 , 103 can be automatically adjusted in its orientation and position, which makes it possible to use the surgical microscope 3 , 103 to be positioned or oriented from a distance so that a certain section of the object field is optimally displayed. For this purpose is the tripod 25th a function control unit 111 assigned, the position or orientation of the surgical microscope on the basis of received position and / or orientation control data 3 , 103 using suitable servomotors. Below are the tripod 25th and from the tripod 25th for the surgical microscope 3 , 103 made possible degrees of freedom based on the 4th and 5 described in more detail.

In the in 4th example shown for a tripod 25th the tripod rests 25th on a tripod base 205 , at the bottom of which rolls 206 are present that have a tripod procedure 25th enable. To prevent the tripod from moving unintentionally 25th to prevent the tripod base 205 also a foot brake 207 .

The actual tripod 25th includes a height-adjustable tripod column as tripod members 208 , a support arm 209 , a spring arm 210 , and a microscope suspension 211 which in turn is a connecting element 213 , a swivel arm 215 and a holding arm 214 includes. The degrees of freedom that the tripod members have for positioning the surgical microscope 3 , 103 make available are in 5 shown. The support arm 209 is at one end about an axis A. rotatable with the stand column 208 connected. At the other end of the support arm 209 is one end of the spring arm 210 around one to the axis A. parallel axis B. rotatably attached, so that the support arm 209 and the spring arm 210 form an articulated arm. The other end of the spring arm 210 is formed by a tilting mechanism (not shown) to which the microscope suspension 211 is attached and which tilts the microscope suspension 211 around the C axis.

The microscope suspension 211 has an axis of rotation D, a pivot axis E and a tilt axis F around which the microscope rotates 3 , 103 can be rotated, swiveled or tilted. With a connector 213 is the microscope suspension 211 at the outer end of the spring arm 210 attached rotatably about the axis of rotation D. The axis of rotation D extends along the connecting element 213 . To the connector 213 a swivel arm closes 215 with the help of which the microscope 3 , 103 , more precisely one on the swivel arm 215 attached holding arm 214 at which the microscope 3 , 103 is attached by means of a microscope holder (not shown), can pivot about the pivot axis E. The pivot axis E extends through the pivot arm 215 . The angle between Swivel arm 215 and connecting element 213 , ie the angle between the pivot axis E and the axis of rotation D, can by means of a between the connecting part 213 and the swivel arm 215 arranged adjustment mechanism can be varied.

Through the holding arm 214 The tilting axis F, which tilts the surgical microscope, runs perpendicular to the representation plane 3 , 103 enables. The surgical microscope 3 , 103 is by means of a microscope holder, not shown, on the support arm 214 attached.

The degrees of freedom of the microscope suspension 211 as well as the setting options of the surgical microscope 3 , 103 , for example. Focusing, sharpness, magnification factor, etc., can be done via an adjusting device 202 be set, which is shown in the present embodiment as a foot switch. However, it can also be implemented as a manual switching element or as a combination of both. Remote control via radio is also possible.

About unintentional adjustment of the microscope 3 , 103 To prevent from a selected position, the tripod links or the joints between the tripod links are provided with fixations (not shown).

Even if the tripod 25th has been described on the basis of a specific example, a person skilled in the art will recognize that other types of stand constructions can also be used, for example a stand construction as shown in FIG DE 20 2007 034 286 A1 is described.

The sequence of an intraoperative optical imaging process according to the invention is described below with reference to FIG 6th described. The figure shows a flow diagram which relates to the monitoring of the position and / or the orientation of the surgical microscope 3 , 103 relative to the brain operation field 5 concentrated. The actual intraoperative imaging process takes place as has been described with reference to the exemplary embodiment for the intraoperative optical imaging system, and is described within the scope of the flow chart in FIG 6th not reproduced in detail.

• - Ausführen der Stimulationszyklen;
• - Aufnehmen einer Videosequenz vom Gehirnoperationsfeld 5 während der Ausführung der Stimulationszyklen;
• - Auswertung der Einzelbilder der Videosequenz und
• - Überwachung der Lage und/oder der Orientierung des Operationsmikroskops 3, 103 relativ zu dem Gehirnoperationsfeld 5.

After starting the intraoperative optical imaging process in step S1 will be in step S2 started the following processes:

• - execution of the stimulation cycles;
• - Record a video sequence from the brain surgery field 5 during the execution of the stimulation cycles;
• - Evaluation of the individual images of the video sequence and
• - Monitoring of the position and / or the orientation of the surgical microscope 3 , 103 relative to the brain operation field 5 .

The following description focuses on the monitoring of the position and / or the orientation of the surgical microscope 3 , 103 relative to the brain operation field 5 as well as measures that are taken if it is found during the monitoring that a deviation in the position and / or orientation of the surgical microscope 3 , 103 relative to the brain operation field 5 of a target position and / or a target orientation relative to the brain operation field 5 present.

As part of the monitoring takes place in step S3 a detection of the position and the orientation of the surgical microscope 3 , 103 relative to the brain operation field 5 . A navigation system can be used for recording 31 Find use, for example, a navigation system 31 how it related to 1 has been described in the context of the description of the first exemplary embodiment for the intraoperative optical imaging device according to the invention. Other types of navigation systems can of course also be used. Except for navigation systems 31 software applications can also be used to record the position and / or the orientation of the surgical microscope 3 , 103 relative to the brain operation field 5 based on the recorded images. For this purpose, for example, an algorithm can be present that uses recorded stereo images to recognize topographical details of the brain surgical field in the image and, from the position and orientation of the recognized typological details, the position and orientation of the surgical microscope 3 , 103 relative to the brain operation field 5 can determine.

In step S4 a comparison then takes place in step S3 detected position and the detected orientation of the surgical microscope 3 , 103 relative to the brain operation field 5 with a target position and a target orientation of the surgical microscope 3 , 103 relative to the brain operation field 5 . In the present exemplary embodiment, this comparison is made by the determination device 11 executed. Based on the comparison carried out, this determines the difference between the recorded position and the recorded orientation on the one hand and the target position and the target orientation on the other.

In step S5 the investigative body decides 11 using the in step S4 determined difference, whether a deviation of the detected position and / or the detected orientation from the Target position and / or target orientation is present. A threshold value for the maximum permissible difference between the detected position and / or detected orientation and the desired position and / or the desired orientation can be established, based on which the decision is made as to whether or not there is a deviation. As long as the difference between the detected position and / or the detected orientation on the one hand and the target position and / or target orientation on the other hand is below the threshold value, the determination device decides 11 in step S5 that there is no deviation. The procedure then goes to step S6 away.

In step S6 it is checked whether the executing stimulation cycles as well as the recording of the video sequence and the evaluation of the individual images have already ended or not. If in step S6 it is established that the execution of the stimulation cycles, the recording of the video sequence and the evaluation of the individual images have ended, the method proceeds to step S7 in which the monitoring is ended. Then the intraoperative optical imaging procedure is performed with step S8 completed. If in step S6 on the other hand, it is established that the execution of the stimulation cycles, the recording of the video sequence and the evaluation of the individual images have not yet ended, the method returns to step S3 back.

In the present exemplary embodiment, both the determination device 11 as well as the compensation device 13 Part of a control unit 14th with which the nerve stimulator 1 as well as the camera 17th of the surgical microscope 3 , 103 being controlled. This control unit 14th can have a dedicated checking module for checking whether the execution of the stimulation cycles, the recording of the video sequence and the evaluation of the individual images have already ended. However, there is also the option of checking by the investigation facility 11 or the compensation device 13 to have done. In the present exemplary embodiment, the check is carried out by the compensation device 13 carried out.

If the investigation unit 11 in step S5 decides that the in step S4 determined difference between the detected position and / or the detected orientation of the surgical microscope 3 , 103 on the one hand and its target position and / or target orientation on the other hand exceeds the predetermined threshold value, the method goes to step S9 continues, in which checks whether the execution of the stimulation cycles, the recording of the video sequence and the evaluation of the individual images of the video sequence have already ended. Will in step S9 If it is found that the execution of the stimulation cycles, the recording of the video sequence and the evaluation of the individual images have already ended, the method proceeds to step S7 away.

If in step S9 on the other hand, if it is determined that the execution of the stimulation cycles, the recording of the video sequence and the evaluation of the individual images have not yet ended, the compensation device is interrupted 13 in step S10 the execution of the stimulation cycles, the recording of the video sequence and the evaluation of the individual images. Although the execution of the stimulation cycles is also interrupted in the present exemplary embodiment, these can in principle be continued during the interruption.

In which to step S10 subsequent step S11 checks the compensation device 13 whether the deviation of the recorded position and / or the recorded orientation of the surgical microscope 3 , 103 relative to the brain operation field 5 of its target position and / or target orientation decays or not. This determination can be determined, for example, from the variation over time of the deviation. For this purpose, the position and the orientation of the surgical microscope can be recorded 3 , 103 relative to the brain operation field 5 in step S3 take place over a predetermined period of time, so that the temporal course of the position and orientation and thus the temporal course of the difference between the recorded position and / or the recorded orientation on the one hand and the target position and / or the target orientation on the other hand are determined from the recorded data . This makes it possible to estimate the variation over time.

If the check in step S11 shows that the deviation will subside within a predetermined maximum period, the compensation device waits 13 this period from (step S12 ) before stepping in S13 the interruption ends and continues with the execution of the stimulation cycles, the recording of the video sequence and the evaluation of the individual images. The procedure then returns to step S3 back.

If the check in step S11 shows that the detected deviation does not subside within the predetermined maximum period, for example because it is a static deviation caused by an unintentional displacement of the surgical microscope 3 , 103 and / or the operating table 27 has been caused because there is a non-decaying oscillation or because the decay time of the oscillation would exceed the specified maximum period, the method proceeds to step S14 away. In step S14 a compensation of the occurred deviation is brought about, as far as this is possible. The Compensation device, for example, signals to the controller 16 of the tripod 25th and / or the controller 18th of the operating table 27 (both of which are motor-driven in the present exemplary embodiment) output, which lead to either the surgical microscope 3 , 103 or the operating table 27 or both are repositioned and / or oriented in such a way that the surgical microscope 3 , 103 again the target position and / or the target orientation relative to the brain operation field 5 occupies. If the deviation is an oscillation, a counter-oscillation in the tripod can be used 25th can be generated, which compensates for the detected vibration. As with reference to the in 1 The exemplary embodiment shown has been described for the intraoperative optical imaging device according to the invention, there is also the possibility of determining the deviation with the aid of optical elements of the surgical microscope 3 , 103 or to compensate with the help of digital image processing software. After the compensation in step S14 has been established, the procedure goes to step S13 further, in which the interruption of the execution of the stimulation cycles, the recording of the video sequence and the evaluation of the individual images is ended.

If the compensation for the determined deviation can be set up so quickly that the time between the determination of the deviation and its compensation is so short that the result of the intraoperative optical imaging process is not noticeably impaired by the short-term deviation, the interruption can be initiated the execution of the stimulation cycles, the recording of the video sequence and the evaluation of the individual images can be dispensed with.

The process is carried out until in step S6 or in step S9 it is established that the execution of the stimulation cycles, the recording of the video sequence and the evaluation of the individual images of the video sequence have ended.

Although the determined deviation is automatically compensated within the scope of the present exemplary embodiment, there is also the possibility that the personnel in the operating room can use the determined deviation during the interruption of the intraoperative optical imaging process by manually adjusting the surgical microscope 3 , 103 and / or the operating table 27 compensated. The position and orientation of the surgical microscope can be monitored 3 , 103 relative to the brain operation field 5 as well as the determination of the deviation continued and the determined deviation on a display, for example on the monitor 23 , are displayed. In this way, the staff in the operating room is shown the remaining deviation in each case, so that the staff receive direct feedback regarding the effectiveness of the adjustment of the surgical microscope 3 , 103 and / or the operating table 27 receives.

With reference to the 7th and 8th two further exemplary embodiments for the intraoperative optical imaging system according to the invention are described. These further exemplary embodiments differ from that in FIG 1 exemplary embodiment shown only by the arrangement of the markers 7th and the cameras 9 of the navigation system. The description of these further exemplary embodiments is limited to the description of the differences from that in FIG 1 illustrated exemplary embodiment. Accordingly, in the 7th and 8th only those elements are shown that are necessary to describe the differences. The ones in the 7th and 8th Elements of the intraoperative optical imaging system (not shown) correspond to the elements of the intraoperative optical imaging system 1 and are not described again in order to avoid repetition.

In the in 7th The exemplary embodiment shown for the intraoperative optical imaging system according to the invention are the cameras 9 of the navigation system on the operating table 27 attached. A marker 7th that by the cameras 9 is located on the surgical microscope 3 , 103 . As the patient 29 relative to the operating table 27 not moved, are the position and orientation of the brain operation field 5 in relation to the operating table 27 clearly set so that with the help of the cameras 9 and the Taget 7th directly the location and the orientation of the surgical microscope 3 , 103 relative to the brain operation field 5 can be captured. In other words, the position and orientation of the surgical microscope 3 , 103 can directly in the coordinate system of the operating table 27 and thus in the coordinate system of the brain operation field 5 are recorded. Placing a marker 7th on or in the brain operation field 5 can be omitted.

8th shows an exemplary embodiment for the intraoperative optical imaging device in which the cameras 9 the navigation system on the surgical microscope 3 , 103 are attached. At or in the brain surgery field 5 there is a marker 7th that by the cameras 9 is captured. The marker 7th can, for example, on the retractor with which the brain operation field 5 is kept open, be appropriate. The position and the orientation of the surgical microscope are also directly related to this configuration of the navigation system 3 , 103 relative to the brain operation field 5 detected.

Compared to the in 7th The variant shown in 8th The variant shown has the advantage that there is no costly space around the patient 29 around from the cameras 9 and their fixings on the operating table 27 is taken. In addition, the in 7th shown variant a shift of the brain operation field 5 relative to the operating table 27 and therefore relative to the cameras 9 are not recognized, whereas the in 8th The embodiment variant shown would recognize such a shift. Both the in 7th The variant shown as well as the one in 8th However, compared to the variant shown in FIG 1 The embodiment variant shown has the advantage that the detected position and the detected orientation are already the relative position and the relative orientation between the surgical microscope 3 , 103 and brain operation field 5 correspond. In the in 1 In contrast, it is necessary to use the recorded position and the recorded orientation of the surgical microscope 3 , 103 on the one hand as well as the recorded position and the recorded orientation of the brain operation field 5 on the other hand to calculate the relative position and the relative orientation between the two.

The present invention has been described in detail on the basis of exemplary embodiments for explanatory purposes. However, a person skilled in the art recognizes that there can be deviations from the exemplary embodiments described, which is why the scope of protection of the present invention is intended to be limited only by the features contained in the claims.

List of reference symbols

1

Nerve stimulator

3

Surgical microscope

5

Brain operation field

7th

marker

9

camera

11

Investigative facility

13th

Compensation device

14th

Control unit

15th

electrode

16

control

17th

camera

18th

control

19th

marked brain tissue area

21st

image

23

monitor

25th

tripod

27

Operating table

29

patient

31

navigation system

103

Surgical microscope

105

lens

107A, B

divergent bundle of rays

109A, B

parallel bundle of rays

111

Magnification changer

113A, B

Interface arrangement

115A, B

Beam splitter prism

119

Camera adapter

123

Image sensor

127

Binocular tube

129A, B

Tube lens

131A, B

Intermediate image plane

133A, B

prism

135A, B

Eyepiece lens

137

Display

139

optics

141

White light source

143

Deflection mirror

145

Lighting optics

149 A, B

Focusing lens

161 A, B

Image sensor

163 A, B

Display

165 A, B

Eyepiece lens

167 A, B

electric wire

202

Foot switch

205

Stand base

206

role

207

Foot brake

208

Stand column

209

Beam

210

Spring arm

211

Microscope suspension

213

Connecting element

214

Holding arm

215

Swivel arm

S1

Start of the intraoperative optical imaging process

S2

Start of the execution of the stimulation cycles, the recording of the video sequence and the evaluation of the individual images of the video sequence as well as start of the monitoring

S3

Detection of the position and the orientation of the surgical microscope relative to the brain operating field

S4

Comparison of the recorded position and the recorded orientation with the target position and the target orientation

S5

Decision whether there is a discrepancy

S6

Check whether the execution of the stimulation cycles, the recording of the video sequence and the evaluation of the individual images have been completed

S7

Stop monitoring

S8

End of the intraoperative optical imaging process

S9

Check whether the execution of the stimulation cycles, the recording of the video sequence and the evaluation of the individual images have been completed

S10

Interruption of the execution of the stimulation cycles, the recording of the video sequence and the evaluation of the individual images

S11

Check whether the deviation subsides

S12

Wait

S13

End interruption

S14

Set up compensation for the deviation

Claims (17)

Intraoperative optical imaging method for finding brain tissue areas connected to at least one stimulated brain function in a brain operation field (5) in which images of the brain operation field (5) with and without stimulation of the at least one brain function are recorded with the aid of an optical imaging device (3, 103) and the recorded images to find the brain tissue areas associated with the stimulated brain function are evaluated by means of an algorithm, characterized in that the position and / or the orientation of the optical imaging device (3, 103) relative to the brain operation field (5) is monitored while the images are being recorded. takes place and, if a deviation in the recorded position and / or the recorded orientation from a target position and / or a target orientation is determined in the course of the monitoring, measures are taken to reduce the effect of the determined deviation on the images of the Reduce brain operation field (5). Intraoperative optical imaging method according to Claim 1 , characterized in that as a measure to reduce the effect of the determined deviation on the images of the brain surgery field (5) the recording and / or the evaluation of the images is interrupted until the deviation is no longer present. Intraoperative optical imaging method according to Claim 2 , characterized in that the determined deviation is of a fading nature and the interruption of the recording and / or the evaluation of the images is maintained until the determined deviation has faded away. Intraoperative optical imaging method according to Claim 2 or Claim 3 , characterized in that the determined deviation is of a permanent nature and the interruption of the recording and / or the evaluation of the images is maintained until the determined deviation is compensated. Intraoperative optical imaging method according to Claim 4 , characterized in that the determined deviation is continuously recorded during the interruption and shown on a display (23). Intraoperative optical imaging method according to one of the Claims 1 to 4th , characterized in that the position and / or the orientation of the optical imaging device (3, 103) relative to the brain operation field (5) can be changed by means of a motor and the compensation of the determined deviation by means of a control or regulating unit (16) acting on the motors of the drive , 18), which, based on the determined deviation, outputs control signals to compensate for the determined deviation to the motors. Intraoperative optical imaging method according to one of the Claims 1 to 4th , thereby characterized in that the determined deviation is compensated for by means of an optical element of the optical imaging device (3, 103). Intraoperative optical imaging method according to one of the Claims 1 to 4th , characterized in that the determined deviation is compensated by means of a digital image processing method which, on the basis of the determined deviation, calculates an image transformation with which the determined deviation can be compensated for in the respective image. Intraoperative optical imaging method according to one of the Claims 1 to 8th , characterized in that the position and / or the orientation of the optical imaging device (3, 103) relative to the brain operation field (5) is detected with the aid of a navigation system (31). Intraoperative optical imaging method according to one of the Claims 1 to 8th , characterized in that the position and / or the orientation of the optical imaging device (3, 103) relative to the brain operation field (5) is detected with the aid of digital image processing based on recorded images. Intraoperative optical imaging method according to one of the Claims 1 to 8th , characterized in that the topography of the brain surgery field (5) is determined and the position and / or the orientation of the optical imaging device (3, 103) relative to the brain surgery field (5) is determined on the basis of the determined topography. Intraoperative optical imaging system with - A nerve stimulator (1) for stimulating at least one brain function in a brain operation field (5); - An optical imaging device (3, 103) for recording images of the brain operation field (5) with and without stimulation of the at least one brain function; - A monitoring device (7, 9, 31) for monitoring the position and / or the orientation of the optical imaging device (3, 103) relative to the brain operation field (5); a determination device (11) for determining a deviation in the position and / or the orientation of the optical imaging device (3, 103) from a desired position and / or a desired orientation and - A compensation device (13) for reducing the effects of the determined deviation on the images of the brain operation field (5). Intraoperative optical imaging system according to Claim 12 , in which the monitoring device for detecting the position and / or the orientation of the optical imaging device (3, 103) relative to the brain operation field (5) comprises a navigation system (7, 9, 31). Intraoperative optical imaging system according to Claim 12 , in which the monitoring device for detecting the position and / or the orientation of the optical imaging device (3, 103) relative to the brain operation field (5) comprises digital image processing software which detects the position and / or the orientation on the basis of recorded images. Intraoperative optical imaging system according to Claim 12 , in which the monitoring device for detecting the position and / or the orientation of the optical imaging device (3, 103) relative to the brain operation field (5) comprises at least one depth sensor. Intraoperative optical imaging system according to one of the Claims 12 to 15th , in which the compensation device comprises at least: - a motor-driven stand (25) to which the optical imaging device (3, 103) is attached, or - a motor-driven operating table (29) or - at least one movable optical element of the optical imaging device (3 , 103) or a digital image processing module which, on the basis of the determined deviation, calculates an image transformation with which the determined deviation can be compensated for in the recorded images. Intraoperative optical imaging system according to one of the Claims 12 to 16 in which the optical imaging device is a surgical microscope (3, 103) or part of a surgical microscope (3, 103).

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