DE102019108129A1 - Method for the motorized movement of a surgical microscope - Google Patents

Abstract

The invention relates to a method for positioning a surgical microscope (1), the surgical microscope (1) comprising microscope optics (16) which are arranged on a motor-driven stand (3), comprising the following method steps: a) triggering a positioning request in the direction an object to be observed (27), b) checking compliance with a minimum distance between the microscope optics (16) and the observed object (27) based on the focusing of the microscope optics (16), and c) deciding whether a motorized positioning of the surgical microscope (1) in Direction of the observed object (27) is permissible.

Description

The invention relates to a method for motorized positioning of a surgical microscope.

Surgical microscopes are used in medicine for operations in which it is expedient to enlarge parts of organs or tissue of a patient located in the operating field. The surgical microscope is usually mounted on a tripod which is driven by a motor. The motorized positioning of the surgical microscope can be controlled via switches or operating levers on the handle, such as a joystick, but also via a foot switch or another user interface. In order to protect the patient and to avoid collisions between the surgical microscope and the patient, current safety concepts provide that motorized journeys that are carried out with the handle or foot control may not be carried out in the direction of the patient (z direction) for safety reasons. A defective button on the handle, which makes it no longer possible to stop positioning, is regarded as a possible error. For the movement in the plane (x / y direction), a limitation of the distance covered in the x / y direction is usually defined after which the drive is automatically stopped. While only small traverse paths are often covered in the x / y plane, significantly larger changes in distance, for example> 300mm, are desirable in the application in the z direction, so that a limitation of the traverse path can lead to an interruption of the positioning, which is disadvantageous Limitation of functionality for the user leads. In addition to these journeys guided by the user, the surgical microscope also provides for the operating microscope to move to previously stored positions. For example, the position of a biopsy removal point can be saved and approached again later. The position and location of the surgical microscope in the room and the focus setting are saved so that the user can view the identical point on the patient. The usual safety concept provides for an operation in the manner of a dead man's switch, so the user must continuously operate a switch on the handle or foot switch while driving. This is often perceived as annoying by users. Due to the greatly improved cameras and screens, more and more users are no longer working through the microscope but looking at a screen, which means that the use of manual positioning of the surgical microscope is increasingly impairing the ergonomics of work processes.

The object of the present invention is to provide a method which solves the disadvantages of the prior art described above.

This object is achieved by a method with the features of the independent claim. The subclaims relate to advantageous developments and variants of the invention.

1. a) Auslösen eines Positionierwunsches in Richtung eines zu beobachtenden Objektes,
2. b) Prüfung der Einhaltung eines Mindestabstandes der Mikroskopoptik zu dem beobachteten Objekt anhand der Fokussierung der Mikroskopoptik auf das zu beobachtende Objekt, und
3. c) Entscheidung, ob ein motorisches Positionieren der Mikroskopoptik in Richtung des beobachteten Objektes zulässig ist.

A method according to the invention for positioning a surgical microscope, wherein the surgical microscope comprises microscope optics which are arranged on a motor-driven stand, comprising the following method steps:

1. a) Triggering a positioning request in the direction of an object to be observed,
2. b) checking compliance with a minimum distance between the microscope optics and the observed object based on the focusing of the microscope optics on the object to be observed, and
3. c) Decision as to whether motorized positioning of the microscope optics in the direction of the observed object is permissible.

The positioning request can be triggered in particular by actuating a joystick, a foot pedal, a touchscreen or another input interface. The input interface can also be designed as an acoustic, such as voice recognition, or gesture-controlled interface.

The test of compliance with the minimum distance includes a test of the focus of the microscope optics on the object to be observed, i.e. a test of the quality of the focus that is present when the positioning request is triggered, which does not mean that focusing on the object to be observed by the Microscope optics is carried out. The test can include, for example, determining the distance between the two laser points used for autofocusing. The distance between the laser points is a measure of the focus. If the two laser points are on top of each other, the microscope optics are in what is known as the best focus, and the image is the sharpest. The further the points are apart, the greater the deviation from the best focus and thus the uncertainty of the distance between the microscope optics and the object to be observed. Consequently, a range or a threshold value is defined for the distance that the laser points are allowed to have from one another and at which the distance between the surface of the object being viewed and the focal plane of the best focus is only a few millimeters. From the current position of the optical elements used for focusing and thus the current focal length of the microscope optics, in connection with the determined distance between the laser points, it can be derived what distance the current focal plane has from the surface of the observed object (i.e. in particular the patient). In the worst case, the focal plane is practically in the patient and the distance between the laser points exceeds the threshold value. From this it can be deduced that the minimum distance has not been reached. It is also conceivable that the focal plane lies well above the patient - in this case too, the distance between the laser points could exceed the threshold value, so that motorized positioning could also be blocked without further measures. It is of course conceivable to differentiate the two cases by taking further measures.

In comparison to focusing the microscope optics on the best focus and the resulting determination of the exact distance between the microscope optics and the object to be observed, determining the distance between the laser points has the advantage that the distance between the laser points can be detected very quickly. The test can therefore be carried out after the positioning request has been triggered in a period of time that is imperceptible to the operator, which contributes to good operability. In addition to the method described here, other options for checking the focus are also conceivable, for example via the contrast of the image.

Furthermore, a positive decision about motorized positioning in the direction of the object to be observed can only be made after a positive check of the focusing of the microscope optics. The focusing test is positive if the distance between the laser points is within the previously defined range or below the threshold value. If the distance between the laser points is outside the defined area or above the threshold value, a negative decision is made about positioning the surgical microscope in the direction of the object to be observed, i.e. the positioning request is not granted. Afterwards, for example, an autofocusing of the surgical microscope can be started, after which the laser points are again in the defined area and a renewed check is consequently positive.

In particular, the autofocus device can be active during the positioning of the surgical microscope. This can also include that the autofocus device is always automatically activated after the first check of compliance with the minimum distance between the surgical microscope and the object to be observed. If the decision is positive, the microscope optics continuously focus on the object to be observed during positioning. If the test and the subsequent decision are negative, focusing is continued without further delay until - if possible - successful focusing has taken place and the positioning process is subsequently started.

As a result, the focusing can be checked in situ during positioning, which also enables constant control of the minimum distance of the microscope optics from the object to be observed during positioning.

Furthermore, the current distance to the observed object in order to maintain the minimum distance can be determined by an autofocus device of the surgical microscope. The distance between the surgical microscope and the object can then be determined on the basis of the position of the optical elements used for focusing and thus the current focal length of the microscope optics. This can be used to check compliance with a minimum distance. Surgical microscopes usually have a working distance of 200mm to 600mm, the focusing unit of the microscope optics being designed so that a focused image can be set in the area used by the working distance. The position of the surgical microscope in relation to the object to be observed is not changed by the focusing. If the surgical microscope is moved outside of the work area, the focus unit of the microscope optics can no longer focus sufficiently, which means that the decision about motorized positioning of the surgical microscope is negative when checking for compliance with a minimum distance and the positioning is not started or canceled.

In particular, the minimum distance can be defined by the minimum working distance of the surgical microscope. The use of the focus to check compliance with a minimum distance leads to a quasi-automatic stopping of travel just below the minimum working distance when the operating microscope falls below the lower working distance. The exact minimum distance that can be approached is defined by the minimum working distance, the correction options of the focus unit of the microscope optics and the permissible range for the quality of the focusing, as described above, on which the checking of compliance with the distance is based.

It is also conceivable to determine the minimum distance on the basis of alternative criteria, for example in cases in which accessories are attached to the microscope which protrude beyond the last optical element of the microscope in the direction of the patient. In this case, the minimum distance would have to be increased accordingly.

In addition, the distance to the observed object to maintain the minimum distance can be determined by an additional sensor of the surgical microscope. This increases the security compared to the autofocusing and with a suitable selection of the sensors, for example, areas outside the field of view of the microscope can also be checked. The additional sensors can for example include capacitive, inductive, optical or also ultrasonic sensors.

Furthermore, to check a malfunction, a travel path of the surgical microscope can also be used to determine the distance of the surgical microscope from the object to be observed. The distance can be determined from the last determined distance and the movement of the microscope optics.

In particular, the travel path can be determined on the basis of the values of the angle and position sensors of the motorized stand. These are used for positioning the surgical microscope and are therefore usually already available to the controller.

Furthermore, the travel path can be determined on the basis of the position of several markers on the surgical microscope that can be recorded by cameras. The travel path can be determined by the control integrated in the surgical microscope or by an external navigation system, as is often used in operating theaters.

In addition to the positioning request triggered by an input interface, such as a joystick, which includes positioning guided by the operator, the positioning request can also include moving to a position previously stored by the surgical microscope. This is useful when the operator uses one position of the surgical microscope several times. This is the case, for example, if the point at which a biopsy was taken is to be approached again at a later point in time. For this purpose, the position is first saved, with the focus setting being saved in addition to the location and position of the surgical microscope. At a later point in time, the operator can select the previously saved position and the surgical microscope moves to it again.

In particular, the input interface can be actuated continuously during motorized positioning. This can be useful in the case of a guided positioning of the surgical microscope by the operator or as an additional control of the travel path when approaching a previously defined point.

Furthermore, the input interface can only be actuated to start the motorized positioning without the operator having to keep a button or switch permanently pressed. This advantageously increases the ease of use.

• 1 den prinzipiellen Aufbau eines Operationsmikroskops, in welcher die Erfindung verwirklicht sein kann,
• 2a, b eine Detailansicht einer Ausführungsform einer Autofokusvorrichtung, und
• 3 ein Flussdiagramm zu einem erfindungsgemäßen Verfahren.

In the following, exemplary embodiments and variants of the invention are explained in more detail with reference to the drawing. Show it

• 1 the basic structure of a surgical microscope in which the invention can be implemented,
• 2a, b a detailed view of an embodiment of an autofocus device, and
• 3 a flowchart for a method according to the invention.

1 shows the basic structure of a surgical microscope 1 in which the invention can be implemented, the invention also in any other embodiment of a surgical microscope 1 can be realized, which is a movement of a microscope optics 16 in the direction of the object to be observed 27 allows. The surgical microscope 1 includes a tripod 3 , which on a body 2 is arranged, which in turn on a pedestal 4th is stored. At one end of the tripod 3 is the microscope optics 16 arranged. The other end of the tripod 3 is with the body 2 connected, the one on the pedestal 4th about a first axis perpendicular to the ground 5 can be rotated. The connection of the tripod 3 to the body 2 is as a second axis parallel to the ground 6th trained so that the tripod 3 and thus also the microscope optics 16 around this axis 6th can rotate. A first kinematics segment 11 connects the second axis 6th with a third, to the second axis 6th parallel axis 7th . A second kinematics segment 12 connects the third axis 7th with a fourth axis 8th that are perpendicular to the third axis 7th runs. A third kinematics segment 13 connects the fourth axis 8th with a fifth axis 9 which in turn are perpendicular to the fourth axis 8th runs and this intersects in a common, not separately designated point. A fourth kinematics segment 14th connects the fifth axis 9 with a sixth axis 10 that are perpendicular to the optical axis 50 (z-axis) of the microscope optics 16 runs. The microscope optics 16 can be viewed as a fifth kinematics segment; it can be controlled by the motor-driven axes 5 , 6th , 7th , 8th , 9 , 10 be moved in six degrees of freedom. The operator makes the movement with the aid of a joystick (not shown in the figure) on the handle 19th or with the help of a joystick 23 at a foot switch 22nd being controlled. Alternatively, by switch 21st , 24 on the handle 19th or foot switch 22nd positions saved in advance can be selected using the surgical microscope 1 after selecting the position and a Start command can move to this position independently, i.e. without the operator using one of the switches 21st , 24 must hold down. Another mode changes the position of the microscope optics 16 in space in relation to the object to be observed 27 such as a patient shown schematically 27 standing on a table 28 under the microscope optics 16 is arranged, the focus point on the object 27 remains the same. As a result, the same point of the operating field can be viewed from different directions, which gives the operator a better overview of the operating field. The control 26th is in the body 2 of the surgical microscope 1 arranged. The microscope optics 16 is a coordinate system 36 assigned, which its origin on the surface of the last lens of the microscope optics 16 Has.

The surgical microscope 1 further comprises an autofocus device (not shown in the figure), which is set up to image the microscope optics 16 to focus, i.e. to focus the image. The image can optionally be recorded with a camera and on one on the body 2 of the surgical microscope 1 arranged screen 18th can be transmitted or directly via an on the microscope optics 16 arranged eyepiece 17th be considered. If the image is sharp, the focus distance, i.e. the distance between the microscope optics 16 to the object 27 , through the controller 26th to be determined. Surgical microscopes 1 usually have a working distance of 200mm to 600mm, whereby focusing is only possible in this area, i.e. focusing can no longer be technically realized with a smaller or larger working distance.

2a shows a detailed view of an embodiment of the autofocus device 31 . To simplify the representation, in 2a only the microscope optics 16 with the handles 19th and an eyepiece 17th as well as a surface of the object 27 shown. The handles 19th each include a joystick 20th and four switches 21st , being the number of switches 21st , which can be designed, for example, as a toggle switch or push button switch, is chosen at random and also more or less switches 21st or joysticks 20th on the handle 19th can be arranged. The origin of the coordinate system 36 is on the underside of the microscope optics in the example shown 16 which is the outer surface of the last lens of the microscope optics 16 corresponds. The autofocus device 31 comprises a device (not shown) for generating two laser beams 32 , 33 that are switched on when required. The microscope optics 16 and the laser beams 32 , 33 are arranged so that the two laser beams meet 32 , 33 hit in a point when the microscope optics 16 is set so that the image is in focus, i.e. the object 27 in the focus of microscope optics 16 stands. In 2a is a distance A between the laser points 34 , 35 of the two laser beams 32 , 33 shown, from which it follows that the microscope optics 16 not optimally on the object 27 is focused. On the basis of the distance A, the control can determine which of the optical elements within the microscope optics that are responsible for focusing 16 must be proceeded and by how much. The distance A also provides a measure of the defocusing, that is to say the deviation of the current focal plane from the surface of the object being viewed 27 on. The degree of focusing and thus the deviation from the best focus plane can therefore be inferred very quickly from the distance between the points. Should the microscope optics 16 now in the direction of the object 27 are positioned, the distance between the laser points is determined before positioning 34 , 35 determined on the object. Are the points 34 , 35 within a predetermined tolerance range 38 who is in 2a is shown as a circle, the position of the microscope optics deviates 16 only a few millimeters from the focused position. The tolerance range 38 is expediently chosen so that the distance between the microscope optics 16 of the object to be observed 27 can be determined with sufficient accuracy, an accuracy of a few millimeters at a working distance of 200mm to 600mm being sufficient. Because a focusing outside the working area of the surgical microscope 1 is not technically possible, the checking of the focus reliably ensures that the distance between the microscope optics 16 and the object to be observed 27 is not less than the distance of the minimum working distance that can still be focused minus the tolerance range of the permitted defocusing.

2 B shows a further detailed view of an autofocus device 31 , paying attention to the appearance of the handles 19th and the eyepiece 17th has been omitted for the sake of clarity. The laser points 34 , 35 of the laser beams 32,33 of the autofocus device 31 have a distance B that is greater than the diameter of the tolerance range shown as a circle 38 is. The known distance between the microscope optics, which was last determined by focusing 16 and the object 27 is no longer within the permissible tolerance range and a decision about motorized positioning cannot be made positively. In addition to the method just described, the status of the focusing as a value for the decision on whether to enable motorized positioning of the microscope optics 16 in the direction of the object 27 to use, the decision can also be based on the determination of the distance between the microscope optics 16 and the object 27 via an additional distance sensor 29 , which is designed as a laser triangulation sensor, for example. This determines the distance through the movement of the object 27 reflected measuring beam 30th on one in the sensor 29 arranged CCD camera. Alternatively, the additional sensor 29 can be used as a second measuring system for checking or safeguarding the method described above with the focusing. Another way of increasing the distance between the microscope optics 16 and the object to be observed 27 to be determined is an external navigation system (not shown). This will be done on the microscope optics 16 arranged markers 37 recorded by permanently installed and / or movable cameras and from this the position and location of the microscope optics 16 determined in space. The position of the object 27 is also known in space, so the distance between the microscope optics 16 and the object 27 can be determined.

3 shows a flowchart for positioning a surgical microscope according to the invention 1 with microscope optics 16 which are attached to a motorized stand ( 3 ) is arranged, and an autofocus device 31 .

In a first process step 40 becomes a positioning request in the direction of an object to be observed 27 triggered.

In a second process step 41 compliance with a minimum distance to the observed object is based on an examination of the focus of the microscope optics 16 on the object to be observed 27 checked.

In a third process step 42 is a decision whether a motorized positioning of the microscope optics 16 in the direction of the observed object 27 is allowed.

List of reference symbols

1

Surgical microscope

2

Body

3

tripod

4th

Pedestal

5

Axis 1

6

Axis 2

7th

Axis 3

8th

Axis 4

9

Axis 5

10

Axis 6

11

Kinematics segment 1

12th

Kinematics segment 2

13

Kinematics segment 3

14th

Kinematics segment 4th

16

Microscope optics

17th

eyepiece

18th

screen

19th

Handles

20th

joystick

21st

counter

22nd

Foot switch

23

joystick

24

counter

26th

control

27

object

28

table

29

Distance sensor

30th

Measuring beam distance sensor

31

Autofocus device

32

laser beam 1

33

laser beam 2

34

Laser point 1

35

Laser point 2

36

Coordinate system surgical microscope

37

marker

38

Focusing tolerance range

40

Process step 1

41

Process step 2

42

Process step 3

50

optical axis microscope optics

Claims (14)

Method for positioning a surgical microscope (1), wherein the surgical microscope (1) comprises microscope optics (16) which are arranged on a motor-driven stand (3), comprising the following method steps: a) triggering a positioning request in the direction of an object to be observed (27), b) checking compliance with a minimum distance between the microscope optics (16) and the observed object (27) on the basis of the focusing of the microscope optics (16) on the object (27) to be observed, and c) Decision as to whether motorized positioning of the microscope optics (16) in the direction of the observed object (27) is permissible. Procedure according to Claim 1 , characterized in that only after a positive check of the Focusing of the microscope optics (16) a positive decision is made about motorized positioning in the direction of the object (27) to be observed. Method according to one of the preceding claims, characterized in that the autofocus device (31) of the surgical microscope (1) is active during positioning. Method according to one of the preceding Claims 1 to 3 , characterized in that the checking of the focus takes place during the positioning in situ. Method according to one of the preceding claims, characterized in that the distance to the observed object (27) in order to maintain the minimum distance is determined by an autofocus device (31) of the surgical microscope (1). Method according to one of the preceding claims, characterized in that the minimum distance is defined by the minimum working distance of the surgical microscope (1). Method according to one of the preceding claims, characterized in that the distance to the observed object (27) in order to maintain the minimum distance is determined by an additional sensor (29) of the surgical microscope (1). Method according to one of the preceding claims, characterized in that, in order to check a malfunction, a travel path of the surgical microscope (1) is additionally used to determine the distance between the surgical microscope (1) and the object (27) to be observed. Procedure according to Claim 8 , characterized in that the travel is determined on the basis of the values of the angle and position sensors of the motorized stand (3). Procedure according to Claim 8 , characterized in that the travel path is determined on the basis of the position of several markers (37) on the surgical microscope (1) which can be detected by cameras. .Method according to one of the preceding claims, characterized in that the positioning request is triggered by actuating a joystick (20, 23), a switch (21, 24), touch screen or another input interface. Method according to one of the preceding claims, characterized in that the positioning request comprises moving to a position previously stored by the surgical microscope (1). Method according to one of the Claims 11 or 12 , characterized in that the input interface (19, 20, 21, 22, 23, 24) is operated continuously during the motorized positioning. Method according to one of the Claims 11 or 12 , characterized in that the input interface (19, 20, 21, 22, 23, 24) is only actuated to start the motorized positioning.

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