DE102010040987A1 - Method for placing a laparoscopic robot in a predeterminable relative position to a trocar - Google Patents

Abstract

In a method for placing a laparoscopic robot (8) with an instrument arm (14) that can be moved isocentrically around its isocenter (18) in a predeterminable relative position (R) to a trocar (20) placed in a patient (2): 20) a location marker (24) that can be located from outside the patient (2) is attached, - the location (PT) of the trocar (20) is recorded using the location marker (24), - the actual position (I) of the isocenter (18 ) - the laparoscopic robot (8) is moved based on the actual position (I), the local position (PT) and an error minimization method (28) so that the relative position (R) is reached.

Description

The invention relates to a method for placing a laparoscopic robot with an isocentrically movable instrument arm in a predeterminable relative position to a trocar placed in a patient.

Minimally invasive interventions are becoming increasingly important in the field of clinical surgery. Whereas small surgeries opened relatively large areas of the site only a few years ago to allow the surgeon to navigate through natural landmarks, it can be seen that a variety of these procedures are now performed by laparoscopy and optical endoscopy. As a further development of classic laparoscopy, robot-assisted surgery has meanwhile taken hold in some areas of medicine. In urology, gynecology or cardiology. She is about to assert herself in the medical routine.

A laparoscopic robot is known for example in the form of the model "da Vinci" of the company "Intuitive Surgical". This robot has a first instrument arm which carries an endoscope at its front end. Up to three additional instrument arms carry laparoscopic instruments.

For each of the endoscope and each of the instruments, a trocar is placed in the patient, through which the respective tool is to be introduced into the patient, in order then to perform a robot-assisted, minimally invasive procedure on the patient. A pivot movement of individual instruments takes place during the operation around a pivot point. This is placed so that it is located in the center or interior of the respective trocar. The pivot point is also in the area of the penetration of the patient, so z. B. in the area of penetration of the abdominal wall. The position of the pivot point must be communicated to the system manually during surgical preparation.

From the submitted on 17.09.2010 German patent application with the file number 10 2010 040 975.8 a laparoscopic robot is known, which has an endoscope and several instruments. These are arranged together on a single instrument arm in the manner of a C-arm structure. As trocar then z. B. a single-port trocar used, which has multiple bushings. This results in the characteristic that a precisely defined geometry exists between the passages of the trocar and the instruments or the endoscope.

The instruments are also individually movable inside the patient. Access to the patient is via a single, single-port trocar. The movement of the instruments or the robot arm can be constructive because of the C-arm structure only isocentric. In other words, the k-bow structure can only be moved kinematically with the help of the available degrees of freedom around an isocenter fixed relative to the robot. The instrument arm can be moved isocentrically around an isocenter, whereby this is manually again to be placed at the passage point of the instruments through the patient surface, z. B. in the area of the abdominal wall. The isocenter, ie the pivot point of the movement of the robot arm, is therefore placed so that it lies at a fixed point in the center or at least in the interior or in the region of the trocar. The isocentric movements of the robotic arm have as minimal disturbing influence on the trocar or the patient.

In detail, the instrument arm or instruments are first placed so that they are coaxial with an imaginary extended line of the trocar center longitudinal axis outside the patient. In a second step, the instruments or the instrument arm can then be moved axially onto the trocar and through it into the interior of the patient. Although it can be ensured in the first step that the trocar openings are hit in a simple way. However, it is still necessary to determine at which point of the now known line the trocar is located. This is important in order to place the above-mentioned isocenter in the area of the trocar, that is, at the desired fixed point defined by the trocar.

It is also known here to move or move the entire robot together with the isocenter by hand until the isocenter of the robot lies in the desired fixed point of the trocar placed in the patient. For this purpose, the otherwise motorized drives of the robot are switched without force or relevant brakes released. This procedure is time consuming and power consuming.

The object of the invention is to provide an improved method for placing a laparoscopic robot with an isocentrically movable instrument arm in a predeterminable relative position to a trocar placed in a patient.

The object is achieved by a method according to claim 1. The isocentrically operating laparoscopic robot is to be placed in a predeterminable relative position to the already set in the patient, so placed trocar. These Relative position is in particular the above-described position of the isocenter at a desired fixed point within or in the region of the trocar. According to the invention, a location marker which can be located from outside the patient is attached to the trocar. Since the position of the isocentric fixed point is known or predetermined relative to the trocar, the spatial position of the trocar and also of the fixed point is then detected on the basis of the location marker. In a further step, the actual position of the isocenter of the laparoscopic robot is detected. Based on the actual position of the isocenter and the location of the trocar or fixed point, which in other words represents the target position for the isocenter, and on the basis of a Fehlinimierungsverfahrens the laparoscopic robot is moved so that the relative position is reached or the isocenter in the fixed point is moved.

According to the invention, both the entire robot, for. B. on rollers, are moved to align the isocenter on the fixed point. It is also conceivable that the robot a z. B. on the floor by means of rollers movable backbone. On this then a support for the instrument arm is arranged relative to this movable. The carrier defines the isocenter, i. H. the isocenter has a fixed spatial position relative to this. In such a robot can, for. For example, the basic scaffold will initially be moved approximately to the correct position, so that the isocenter lies at least in the vicinity of the fixed point. Subsequently, only the carrier and with this the isocenter relative to the backbone is moved according to the invention. However, it is also possible to use the method according to the invention for coarse positioning of the basic structure.

Throughout the calibration procedure, the isocenter is always tracked, i. H. the actual position of the isocenter is recorded repeatedly and thus the deviation from the position of the fixed point is always recalculated.

In other words, a positional balance between the isocenter of the C-arm or laparoscopic robot and the trocar or the fixed point, ie the desired pivot point of the arm movement is possible by the inventive method.

Gaining valuable surgery time, shorter anesthesia time, and easier robot operation are the direct consequences of the procedure.

The adjustment of the laparoscopic robot to be performed may be suggested to the user by the error minimization method via a suitable display. This shows z. For example, in which directions and how much z. B. certain joints of the robot are to be adjusted or the skeleton is to move. The actual placement of the laparoscopic robot is thus still manual, but supported or guided by the corresponding display.

As an alternative to the aforementioned manual movement, however, the laparoscopic robot can also be moved automatically in an advantageous embodiment. A manual intervention of the staff to place the robot is then no longer necessary, a corresponding display for the o. G. Target movement directions, etc. is then superfluous. The error minimization can therefore be autonomous or automatic, semi-autonomous or manual.

In an advantageous embodiment of the method, the spatial position and / or the actual position are determined by optical detection with the aid of a camera. The place marker is then a visually detectable by the camera or visible marker. This is z. B. then run as at least three trocar mounted marker points. Here are all known from optical navigation systems concepts conceivable, for. As an infrared camera with infrared visible markers such. B. known from the "Polaris" system of the company NDI.

In a preferred embodiment of the method, an endoscope is arranged as a camera on the instrument arm. In the abovementioned laparoscopic robots, an endoscope is present anyway, which z. B. is registered or calibrated in terms of its optical imaging properties in the coordinate system of the laparoscopic robot. This endoscope, which usually serves to navigate the surgical procedure in the patient, then fulfills a dual function as a navigation camera in the placement of the laparoscopic robot or its isocenter. An additional camera is then no longer necessary. In addition, the actual position of the isocenter is then always known by the current camera position. The relative position between isocenter and fixed point degenerates to the camera position relative to the fixed point. A corresponding endoscope camera is often a stereo camera system, which significantly simplifies the necessary spatial location of location markers compared to a single camera.

In a further preferred embodiment of the method, a combination arm for a single-port technique is used as the instrument arm. As already mentioned above, an optimal placement of the pivot point of the isocenter of the laparoscopic robot relative to the patient according to US Pat Invention crucial to minimize the trauma intervention.

In a preferred embodiment of the method, a position-based visual servoing method is performed as the error minimization method. Position-based visual servoing (PBVS) always determines the actual relative coordinates in a reference coordinate system. So z. B. for the location and / or orientation of the isocenter and the instrument arm and the marker Cartesian location coordinates known. By exploiting the properties of homogeneous transformations, the position difference between the trocar and the isocenter of the C-arm can be continuously described as the combination of the different coordinate systems - eg. B. the isocenter, the camera and the C-arm - via appropriate transformation matrices.

In a further advantageous embodiment of the method, a visual-servoing method is carried out as an error minimization method. Visual servoing methods are z. B. " J. Wang and WJ Wilson, '3D relative position and orientation estimation using Kalman filters for robot control', 1992 IEEE Int. Conf. to Robotics and Automation, pp. 2638-2645 (1992) " known. The basis for this is a kinematic highly accurately calibrated system of laparoscopic robot and camera, for which it is known where the position of the isocenter is relative to a base or reference coordinate system defined by the camera. Especially for the above-mentioned variant, that the camera is the endoscope camera integrated in the system, the relative position between the endoscope camera and the located trocar and thus the fixed point is continuously available.

From the projections of the markers in the camera image, so the location of the image features, with known geometry between the markers, z. B. the trocar and the calibrated camera, the position - ie position and orientation - of the trocar with respect to the camera coordinate system estimated or determined. By means of a suitable control law as an error minimization method, the isocenter can then be brought to the location of the fixed point.

In a preferred embodiment, the error minimization method is performed on a Kalman filter as described e.g. B. from the o. G. Article is known.

For a further description of the invention reference is made to the embodiments of the drawings. They show, in each case in a schematic outline sketch:

1 a patient on which a laparoscopic robot is placed.

1 shows a section of a patient 2 namely the abdominal wall 4 with underlying abdomen 6 in an operating room. At the patient 2 a minimally invasive procedure should be performed. The procedure is intended with the help of a laparoscopic robot 8th occur. The robot 8th has a roller bearing, z. B. movable on the floor of the operating room scaffold 10 on. Relative to this movable and on this is a carrier 12 arranged, which an instrument arm 14 wearing. The instrument arm 14 carries laparoscopic instruments at the far end 16 , with the help of which the intervention is to be carried out.

The instrument arm 14 together with the instruments 16 This is an isocenter 18 Isocentric movable, the isocenter to the carrier 12 has a fixed relative position. The instrument arm 14 is a combination arm for a single-port technique, ie the instruments 16 are fixed relative to each other in their relative position on the single instrument arm 14 attached.

For the single-port technique, therefore, is the patient 2 prepared to that in the abdominal wall 4 a single-port trocar 20 is introduced, through which all the instruments 16 in the patient 2 are to introduce. For maximum mobility of the instruments 16 in the abdomen 6 while reaching the abdominal wall 4 of the patient 2 As little as possible to burden, an isocentric movement of the instrument arm 14 the patient 2 weigh as little as possible.

All isocentric pivot movements of the robot 8th should therefore be carried out so that these only a minimal movement of the abdominal wall 4 or the trocar 20 cause. The pivot point of all movements, ie the isocenter 18 , should therefore be in a fixed relative position R with respect to the trocar 20 to be brought.

In a preferred embodiment, the relative position R is defined as follows: the isocenter 18 should be inside or axial center of the trocar 20 at about the level of the abdominal wall 4 lie. For this reason, in a relative fixed position to the trocar 20 a fixed point 22 defined in its interior. The robot 8th should then be placed so that the isocenter 18 at the fixed point 22 to come to rest.

According to the invention is therefore at the trocar 20 one from outside the patient 2 Locable place marker 24 attached. The place marker 24 is in a defined relative position on the trocar 20 attached so that at Local knowledge of the trocar 20 as well as the location of the fixed point 22 is known.

In the present example, the place marker 24 an optical location marker. As a locating device therefore comes to a robot 8th external camera 26 for use. The camera 26 recorded in the 1 indicated field of view now in their camera coordinate system, the position P _{T of} the trocar 20 and thus the one of the fixed point 22 , The camera 26 or an attached, not shown navigation system also detects the actual position I of the Isozentrums 18 , This is done either via one on the instrument arm 14 attached, not shown, from the camera 26 Locable place marker. Alternatively, the location detection in the robot 8th , z. B. via angle and length encoder, the movement position of the degrees of freedom of the robot 8th quantize. All that is required is the geometry of the robot 8th be known.

The location position P _T and the actual position I are sent to an error minimization method 28 transmitted. Based on this, the robot according to the invention 8th moved so that the relative position R is reached. Thus, the isocenter is preferred 18 in the fixed point 22 is moved. This happens z. B. by issuing Verstellhinweisen on a display 30 , The adjustment instructions refer to the degrees of freedom of the robot 8th and are output to unillustrated operators. This manually adjusts the robot according to the information generated according to the method 8th , This leads to an immediate and exact positioning of the isocenter 18 in the desired relative position R or position at the fixed point 22 ,

In an alternative embodiment, there is no indication 30 available. On the basis of the error minimization procedure 28 becomes the robot 8th in terms of its degrees of freedom automatically proceed so that the isocenter 18 in the fixed point 22 arrives.

In an alternative embodiment of the method is the camera 26 no external camera, but one of the instruments 16 is an endoscope 32 , This fulfills the function of the camera or degenerate to the camera 26 ,

The endoscope 32 then put the camera 26 whose field of view is again in 1 is indicated. In this case, the determination of the actual position I in the coordinate system of the camera is simplified 26 or the endoscope 32 because this always embodies the actual position I itself. The reason for this is that the position of the camera kinematically in a known way about the construction of the robot 8th is linked to the actual position I, since these are in relative fixed position to the instrument arm 14 is arranged.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102010040975 [0005]

Cited non-patent literature

• J. Wang and WJ Wilson, '3D relative position and orientation estimation using Kalman filters for robot control', 1992 IEEE Int. Conf. to Robotics and Automation, pp. 2638-2645 (1992) [0021]

Claims (9)

Method for placing a laparoscopic robot ( 8th ) with one around its isocenter ( 18 ) isocentrically movable instrument arm ( 14 ) in a predeterminable relative position (R) to one in a patient ( 2 ) trocar ( 20 ), in which: - at the trocar ( 20 ) from outside the patient ( 2 ) Placeable place marker ( 24 ), - the local position (P _T ) of the trocar ( 20 ) based on the place marker ( 24 ), - the actual position (I) of the isocenter ( 18 ), - based on the actual position (I), the spatial position (P _T ) and an error minimization method ( 28 ) of the laparoscopic robot ( 8th ) is moved so that the relative position (R) is reached. Method according to claim 1, in which - the spatial position (P _T ) of an isocentric fixed point ( 22 ) of the trocar ( 20 ) based on the place marker ( 24 ), - the laparoscopic robot ( 8th ) is moved in such a relative position (R) that the isocenter ( 18 ) in the fixed point ( 22 ) lies. Method according to one of the preceding claims, in which the laparoscopic robot ( 8th ) is moved automatically. Method according to one of the preceding claims, in which the spatial position (P _T ) and / or actual position (I) is determined by optical detection with the aid of a camera ( 26 ) be determined. Method according to claim 4, wherein one on the instrument arm ( 14 ) arranged endoscope ( 32 ) as a camera ( 26 ) is used. Method according to one of the preceding claims, in which as an instrument arm ( 14 ) a combination arm is used for a single-port technique. Method according to one of the preceding claims, in which the method of fault-fixing ( 28 ) a position-based visual-servoing method is performed. Method according to one of the preceding claims, in which the method of fault-fixing ( 28 ) a visual-servoing procedure is performed. Method according to Claim 8, in which the error-fixing method ( 28 ) is performed on a Kalman filter.

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