HK1213461B - Endoscope with a multi-camera system for minimally invasive surgery - Google Patents

Description

Endoscope with multiple camera system for minimally invasive surgery

Technical Field

The present invention relates to an endoscope with a multi-camera system for use in minimally invasive surgery and a corresponding surgical robot, in particular for use in minimally invasive surgery, such as laparoscopy.

Background

Minimally invasive surgery, such as laparoscopic surgery, is performed through the use of surgical instruments, such as forceps, cutters, and stapling tools, which are introduced into the body of a patient via one or more cannulae. Two to four, and in most cases three, surgical instruments are commonly used. In addition to these surgical instruments, a visualization unit is also required, which enables the surgeon to observe the operating region. Such a visualization unit is usually a camera or an endoscope, which is likewise introduced into the patient via a cannula. In general, visualization is performed via an endoscope in which a screen of a surgical field is displayed on an external display in 2D or 3D. In the prior art, numerous endoscopes are known, in which a visualization unit, such as a video camera, is integrated in its distal end. However, in general, an endoscope can have a camera not only at its distal end but also at its proximal end. The images acquired by the endoscope are displayed on one or more external displays via an image transfer system and an image processing unit. A large number of endoscopes are described in the prior art.

Thus, for example, WO2009/057117 a2 describes an endoscope with two devices for imaging. The device for imaging is guided into the body via the cannula and is turned sideways, more precisely at an angle from the longitudinal axis of the cannula, via a flap fixed on the cannula. The two devices for imaging can be pivoted out at different angles, so that two different views can be realized.

The disadvantages of the camera systems or endoscopes described in the prior art are: even if two cameras are provided to photograph the surgical Field, these cameras are not capable of visualizing all surgical instruments simultaneously in any state (konstellantion) in which only the direct Field of operation is visualized, due to the varying positions of the surgical instruments and the positions of the endoscopes close to the surgical Field and subject Field angle (FoV) limitations. If the surgical instrument is removed from the surgical field of view, it is no longer captured by the one or more cameras and is no longer under the line of sight control of the surgeon or his assistant.

Disclosure of Invention

The invention is therefore based on the following objects: an improved visualization system for minimally invasive procedures, such as laparoscopic procedures, is provided that enables the surgeon to cooperate instruments in a simplified manner and method through a single cannula or portal into the body or without the need for additional cannulas or portals into the body.

This object is achieved by the invention according to an embodiment thereof by an endoscope and according to an embodiment thereof by a surgical robotic system with a corresponding endoscope.

An endoscope, such as a laparoscope, having a multi-camera system for use in minimally invasive surgery is described.

A first subject of the invention relates to an endoscope for minimally invasive surgery, in particular for use within a robotic system for surgery, the endoscope having:

a main carrier device which extends from the outside into the body over substantially the entire endoscope length and which has at least one illumination unit and two image recording devices on the distal end, wherein the image recording devices are each arranged substantially in the same plane in such a way that they can be pivoted outward from the main carrier device;

a cannula for advancing an endoscope into a body; and

an additional carrier device, which is arranged on the sleeve and/or the main carrier device, wherein the additional carrier device has an additional image recording device on its distal end, which is arranged so as to be pivotable outward from the additional carrier device, and wherein the additional image recording device has an additional illumination unit and at least one additional image sensor, which has a monitoring region, which comprises both monitoring regions of the image recording device of the main carrier device.

The invention has the following advantages: by providing and simultaneously using 2 imaging systems, namely one overview camera and one 3D detail camera, which are introduced into the patient via a single cannula (also a combined cannula), it is possible to generate not only an overview image in at least 2D with a high object field angle (wide angle, for example >90 °), but also a 3D detail image with a typical object field angle of up to 70 °. This achieves that: during the entire duration of a minimally invasive surgery, such as a laparoscopic surgery, the direct surgical field is visualized as well as its additional peripheral areas. In this way all surgical instruments can be visualized simultaneously, even if they are located outside the surgical Field of View of the two image capture devices at the distal end of the endoscope due to their varying positions and the position of the camera or endoscope and the object Field angle (FoV), since the additional image capture devices can capture instruments that are located outside the surgical Field of View of the two image capture devices. This may be the case, for example: surgical instruments are sometimes unnecessarily "parked". This "parking" is in most cases performed outside of the immediate surgical site and outside of the surgical field of view, so that it is out of the way at the time of surgery. According to the invention, the surgical elements thus "parked" are captured by the 2D overview camera according to the invention and thus continuously under the visual control of the surgeon or his assistant. By virtue of the additional image recording device in the form of a 2D overview camera and the image recording device in the form of, for example, 2 image sensors in the form of a 3D detail camera being arranged in each case on the endoscope, the image recordings of the 2D overview camera and the 3D detail camera are tracked without problems for the surgeon via a common or separate image screen, wherein the corresponding cooperation is thereby simple for the surgeon, since the monitoring region of the 2D overview camera, which may optionally have 3D optics, comprises the monitoring region of the 3D detail camera or an object field angle which is greater than the 3D detail camera. It should be mentioned in this connection that the arrangement of 2 separate, completely independently oriented cameras with overlapping monitoring regions, which are not arranged on the endoscope, produces a disadvantageous cooperation for the surgeon, so that the surgeon may "stun" by the 2 completely independent cameras. This problem is solved in a simple manner by an endoscope according to the invention having a 2D overview camera and a 3D detail camera coordinated therewith.

Furthermore, by means of the illumination unit on the main carrier device in combination with the additional illumination unit on the additional carrier device, an improved illumination is achieved, in particular for 3D pictures, so that the image of the 3D detail camera can be shown with an improved quality.

According to a preferred embodiment of the invention, the additional image sensor has a wide-angle optical arrangement which is arranged in the pivoted-out state in the vicinity of the distal end of the cannula.

In particular, it is advantageous if the two image recording devices are each arranged pivotably about a pivot axis on the distal end of the main carrier device, the pivot axes being parallel to one another in a plane, as a result of which the structural complexity is minimized.

Another structural simplification consists in: the additional carrier device rests in particular directly on the main carrier device between the sleeve and the main carrier device, wherein in particular not only the main carrier device but also the additional carrier device is of cylindrical design.

Furthermore, it is advantageous if the image recording device is tiltable about the pivot axis and about a further axis of rotation, respectively, by means of a joint, orthogonally to the longitudinal extension of the carrier device, wherein the rotational movements about the pivot axis and the axis of rotation are decoupled from one another.

According to the invention, it is thus possible, using only one cannula, for the 3D detail camera to be able to move independently of the 2D overview camera with 4 degrees of freedom. The 2D overview camera and the 3D detail camera are in turn coupled to each other with 2 degrees of freedom, the 2D overview camera and the 3D overview camera showing movements about the entry point of the cannula into the body in the x-direction and the y-direction (pivoting movement of the cannula).

Another subject matter of the invention relates to a surgical robotic system having at least one robot arm on which at least one surgical instrument and/or an endoscope for minimally invasive surgery can be arranged, the endoscope having:

a main carrier device which extends from the outside into the body over substantially the entire endoscope length and which has at least one illumination unit and two image recording devices on the distal end, wherein the image recording devices are each arranged substantially in the same plane in such a way that they can be pivoted outward from the main carrier device;

a cannula for passing an endoscope into a body; and

an additional carrier device, which is arranged on the sleeve and/or the main carrier device, wherein the additional carrier device has an additional image recording device on its distal end, which is arranged so as to be pivotable outward from the additional carrier device, and wherein the additional image recording device has an additional illumination unit and at least one additional image sensor, which has a monitoring region, which comprises both monitoring regions of the image recording device of the main carrier device,

an image processing unit is provided which is coupled both to the two image recording devices and to the additional image recording device, and a visualization unit which shows the 2D image data and/or the 3D image data of the image recording device and/or the additional image recording device.

The surgical robotic system according to the invention has in particular the following advantages: the image data are displayed to the surgeon as 2D image data and/or 3D image data as required, i.e., the image data of the overview camera can also be coupled to the image data of the 3D detail camera by means of the image processing unit, so that the surgeon's overview is thus greatly improved by means of a unique image sequence on the visualization unit.

It is therefore particularly advantageous if the additional image sensor has a wide-angle optical arrangement which, in the pivoted-out state, is arranged near the distal end of the cannula.

Further advantageous embodiments of the invention emerge from the following description.

All disclosures of the present invention therefore likewise relate not only to these two camera systems but also to endoscopes which comprise these two camera systems.

In minimally invasive surgery, such as laparoscopic surgery, the patient is accessed via a cannula (usually through the abdominal wall or into the thoracic cavity). Surgical instruments or video cameras or endoscopes can be guided into the body by such a cannula. As mentioned, according to the invention two cameras are introduced simultaneously via one cannula. Since 2 to 4 surgical instruments and at least one camera are usually required for one operation, 3 to 5 cannulas are required.

Drawings

The invention is illustrated purely by way of example with reference to the accompanying drawings. The figures show:

fig. 1 shows a schematic representation of a conventional endoscope in a preferred embodiment of a 3D detail camera, which is arranged on an endoscope according to the invention, which is connected to a visualization unit and an image processing unit of a surgical robotic system, and

FIG. 2 shows a schematic sub-view of another embodiment of a 3D detail camera with an externally connected light source, which is arranged on an endoscope according to the invention, and

FIG. 3 shows a schematic sub-view of another preferred embodiment of a 3D detail camera, which can be realized by means of a reduced number of mechanical adjustment elements, which are provided on an endoscope according to the invention, and

fig. 4 shows a schematic overview of the use of a visualization solution in a surgical robotic system used in minimally invasive surgery, such as laparoscopy.

Detailed Description

The invention is described below with reference to the accompanying drawings:

fig. 1 shows a multi-camera system according to the invention integrated into an endoscope. Is threaded through body tissue 2 via cannula 1 and thereby into the patient. An additional carrier 3 for the 2D overview camera is introduced into the body through the cannula 1. The additional carrier 3 is designed such that it enables a tubular leadthrough of a rotationally symmetrical, rod-shaped further main carrier 4 for the 3D detail camera. Alternatively, a tubular lead-through may also be used for the surgical instrument. The camera mount 5 is fixed to the additional carrier 3 via a joint 6, so that it can be tilted by a pivoting movement 7 by substantially 90 ° relative to the axis of rotation after being threaded through the cannula 1. The camera stand 5 carries an additional image sensor consisting of an image sensor 9 and wide-angle optics imaging optics 8. In order to illuminate the field of view of the object, the camera stand 5 is furthermore equipped with an additional illumination unit, which is formed by a light source 11 and a corresponding wide-angle imaging optics 10. The wide-angle imaging optics 10 are designed such that the entire field of view of the object captured by the image sensor 9 and the wide-angle imaging optics 9 connected thereto is illuminated. The camera stand 5 together with the additional image sensor and the additional illumination unit form a 2D overview camera for generating a 2D overview image. Preferably, the image sensor 9 is constructed as a CCD sensor or a CMOS sensor having a resolution of 1920 × 1080 or more pixels.

The captured image data are supplied via a data line 23 to a processing unit 25, which processes the image data for display and supplies them via a further data line 26 to a visualization unit 27. The visualization unit 27 is able to display not only 2D image data but also 3D image data, for example separately, but also in combination with a unique image or a unique sequence of images. The control of how which image data is displayed is performed by the control unit 32 according to the desires of the operator or surgeon.

At the end of the rotationally symmetrical main carrier 4, there are 2 camera modules or two image recording devices 12a, 13a, 14a, 12b, 13b, 14b, in particular each consisting of two imaging optics 14a and 14b mounted on 2 camera stands 12a and 12 b. The camera frames 12a and 12b are connected with the main carrier 4 via joints 17a and 17b forming pivot axes, so that after introduction into the body they can be tilted by 90 ° in the pivoting direction 18a or 18b relative to the axis of rotation of the main carrier 4. For illuminating the field of view of the object, an illumination unit, which is formed by a light source 15 and imaging optics 16, is mounted on the end of the main carrier 4, to which the reversible camera housings 12a and 12b are also fixed. The camera stands 12a and 12b also carry image recording devices, which are formed by image sensors 13a and 13b and imaging optics 14a and 14 b. The two image recording devices 12a, 13a, 14a, 12b, 13b, 14b together form a 3D detail camera.

The illumination unit formed by the light source 15 and the imaging optics 16 can preferably be formed as a direct LED light source, i.e. the emission angle of the LEDs in combination with suitable imaging optics 16 is selected such that the field of view of the object imaged by the two image sensors 13a and 13b and the imaging optics 14a and 14b connected thereto is completely illuminated. In a modified embodiment, the illumination unit on the proximal end is also formed only by the imaging optics 16. The light source 30 is thus arranged outside the main carrier 4 and thus outside the patient's body. Control instructions to the light source 30 are sent from the processing unit 25 via a data line 31. The light itself is then coupled into a suitable light guide arrangement 28 via a light guide. The light guide 28 is preferably designed, for example, as a fiber optic bundle and guides the coupled-in light to the imaging optics 16. In another embodiment, the light guiding mechanism 28 may also be realized by a suitable rod-shaped optical device.

In a further embodiment (fig. 3), a camera mount 12c is present at the end of the rotationally symmetrical main carrier 4, which camera mount carries two image recording devices 13a, 14a, 13b, 14b, which are in particular each formed by two imaging optics 14a and 14b mounted on the camera mount 12 c. The light source 15 connected to the imaging optics 16 is arranged in this arrangement centrally between the two image recording devices 13a, 14a, 13b, 14b, which are also located on the camera stand 12 c. The camera stand 12c is connected to the main carrier 4 via a joint 17c forming a pivot axis, so that it can be tilted by 90 ° in a pivoting movement 18c relative to the axis of rotation of the main carrier 4 after introduction into the body.

Additionally, the joint 17c is configured such that the camera frame 12c can pivot at least +/-90 ° in a direction 20 about a rotational axis 19 that is orthogonal to a rotational axis 21 of the main carrier 4.

The captured image data are supplied via a data line 24 to a processing unit 25, which processes the image data of the 3D detail camera for stereoscopic display and supplies them via a data line 26 to a visualization unit 27. The visualization unit 27 may display not only 2D image data but also 3D image data. The control of how the respective image data are shown is performed by the processing unit 25.

Fig. 2 illustrates the tilting movement of the 3D detail camera about the rotation and swivel axis. The joints 17a and 17b (see fig. 1) effect a tilting movement of the camera stands 12a and 12b (see fig. 1) of 90 ° starting from the axis of rotation 21 of the main carrier 4.

Furthermore, the joints 17a and 17b may enable a synchronous pivoting movement or tilting of the camera stands 12a and 12b about a rotation axis 19 orthogonal to the rotation axis of the main carrier 4 by substantially +/-90 °. Thereby, a corresponding 3D image can be taken at an angle to the rotation axis 21 of the main carrier 4 without changing the position of the main carrier 4.

Such a synchronous pivoting movement of the camera frames 12a and 12b about the axis of rotation 19, which is orthogonal to the axis of rotation of the main carrier 4, is advantageous in relation to the construction of prior art endoscopes, in which the axis of rotation and the optical axis are identical, that is to say the "obliquely upward" or "obliquely downward" observation requires the endoscope to be tilted by a corresponding angle and thus also the necessary movement space. As a result, the patient's tissue may be too fatigued and may also be damaged. This conventional tilting of the endoscope is not required in the endoscope according to the invention due to the pivoting of the camera stand about the axis of rotation 19. Alternatively, in endoscopes according to the prior art, different optical devices are used, which have a fixed angle different from 0 °, typically 30 °. To replace the endoscopic optics, the surgeon must interrupt the procedure, remove the endoscopic optics, connect another optic to the endoscope, and reintroduce the endoscope through the endoscope cannula into the patient.

Furthermore, the joints 17a and 17b enable decoupled, independent pivoting movements of the camera stands 12a and 12b about a respective rotation axis 19, which is orthogonal to the rotation axis 21 of the main carrier 4, of substantially +/-90 °. This enables a corresponding 2D image to be captured at a larger subject field angle without changing the position of the main carrier 4. For this purpose, the two 2D images are combined in the processing unit 25 (see fig. 1) after transmission via the data path 24 (see fig. 1), so that a 2D image over a larger field angle of the object can thus be displayed on the visualization unit 27 (see fig. 1), which is not possible in conventional endoscopes. If the visualization unit 27 is also adapted to display 3D images, the processing unit 25 can also calculate 3D images as a whole, which 3D images are displayed as three-dimensional images on the visualization unit 27 for the surgeon. The surgeon can capture such a three-dimensional image on the visualization unit 27, for example, by means of optical aids such as shutter glasses or polarized glasses. Alternatively, the visualization unit 27 is designed by means of an optical imaging system such that it projects a left image for the left eye and a right image for the right eye, respectively. In this embodiment, the use of additional optical aids, such as shutter glasses or polarized glasses, can be dispensed with.

In an alternative embodiment according to fig. 3, the camera stand 12c carries two image recording devices 13a, 14a, 13b, 14b and an illumination device consisting of a light source 15 and imaging optics 16. A pivoting movement of the camera support 12c by means of the joint 17c about a rotation axis 19 which is orthogonal to the rotation axis 21 of the main carrier 4 by substantially +/-90 ° thus always acts on the two image recording devices 13a, 14a, 13b, 14b and on the illumination device formed by the light source 15 and the imaging optics 16. In this embodiment, it is advantageous if the imaging optics 16 are optimally adapted to the field angle of the object captured by the image capture devices 13a, 14a, 13b, 14b, since in this embodiment the illumination device pivots together with the image capture devices. In this embodiment, the light source 15 is preferably configured as an LED lighting device.

The position and trajectory of the introduced instrument can be calculated in the processing unit 25 from the data of the 2D overview camera. This trajectory information can be inserted as additional information in a suitable form, for example as an overlay display, when the 3D image is displayed on the visualization unit 27.

Fig. 4 shows an exemplary use of the multiple camera system 43 according to the invention in a telemanipulator or robotic system. The actuators (adjustment drives) are controlled by the surgeon via a display and control unit 32. The control commands generated by means of the display and operating unit 32 are transmitted to the control unit 34 via a data transmission 33. The control unit is connected to the robot unit 37 via a further data line 35 and is equipped with a carrying arm 40, the curved guide 42 being able to be pre-positioned via a joint mechanism 41 depending on the position of the patient on the operating table 38, so that the robot arm 44 effects an optimal positioning of the multi-camera system 43. The image data acquired by the 2D overview camera are supplied via a data line 23 to a processing unit 25, which processes the image data for display and supplies them via a further data line 26 to a visualization unit 27. The visualization unit 27 is able to display not only 2D image data but also 3D image data, for example separately, but also in combination in a single image or a single image sequence. The control of how which image data is to be displayed is performed by the control unit 32 according to the desires of the operator or surgeon. For this purpose, control commands generated by the control unit 32 are transmitted to the processing unit 25 by means of a data line 39.

According to fig. 1, two images can be recorded from different positions of a scene by two image recording devices 12a, 13a, 14a, 12b, 13b, 14b, each consisting of in particular two imaging optics 14a and 14b mounted on 2 camera frames 12a and 12 b. The captured image data are supplied via a data line 24 to a processing unit 25, which processes the image data of the 3D detail camera for stereoscopic display and supplies them via a data line 26 to a visualization unit 27. The visualization unit 27 is capable of displaying not only 2D image data but also 3D image data. The control of how which image data is to be displayed is performed by the control unit 32 according to the desires of the operator or surgeon. For this purpose, control commands generated by the control unit 32 are transmitted to the processing unit 25 by means of a data line 39.

Minimally invasive surgery, such as laparoscopic surgery, is typically performed via surgical manipulators, as well as telemanipulators or robotic systems. The endoscope and camera according to the present invention may be used in such a remote operator or a robot system.

The invention is not limited, however, to the use of an endoscope according to the invention or a camera according to the invention in a telemanipulator or robotic system for minimally invasive surgery, but can also be used independently of such a system in the field of medical applications.

Claims (9)

1. An endoscope for minimally invasive surgery, the endoscope having:

a main carrier device (4) which extends from the outside into the body over the entire endoscope length and which has at least one illumination unit (15, 16) and two image recording devices (12a, 13a, 14a, 12b, 13b, 14 b; 12c) at the distal end, wherein the image recording devices (12a, 13a, 14a, 12b, 13b, 14 b; 12c) are each arranged in the same plane in such a way that they can be pivoted out of the main carrier device (4);

a cannula (1) for entering the endoscope into a body; and

an additional carrier device (3) which is arranged on the sleeve (1) and/or the main carrier device (4), wherein the additional carrier device (3) has an additional image recording device (8, 9, 10, 11) on its distal end, which is arranged in a pivotable manner outwards from the additional carrier device (3), and wherein the additional image recording device (8, 9, 10, 11) has an additional illumination unit (10, 11) and at least one additional image sensor (8, 9) which has a monitoring region which comprises two monitoring regions of the image recording device (12a, 13a, 14a, 12b, 13b, 14 b; 12c) of the main carrier device (4),

it is characterized in that the preparation method is characterized in that,

the additional carrier device (3) is directly applied to the main carrier device (4) between the sleeve (1) and the main carrier device (4), wherein the image recording device (12a, 13a, 14a, 12b, 13b, 14 b; 12c) is arranged in a tiltable manner about the pivot axis (17a, 17 b; 17c) and about a further axis of rotation (19) which is orthogonal to the longitudinal extension of the carrier device (4) by means of a joint (17a, 17 b; 17c), wherein the rotational movements about the pivot axis (17a, 17 b; 17c) and the axis of rotation (19) are decoupled from one another.

2. An endoscope according to claim 1, characterized in that the additional image sensor (8, 9) has a wide-angle optical arrangement (8) which is arranged in the pivoted-out state in the vicinity of the distal end of the sleeve (1).

3. An endoscope according to claim 1 or 2, characterized in that two of the image recording devices (12a, 13a, 14a, 12b, 13b, 14 b; 12c) are each pivotably arranged about a pivot axis (17a, 17 b; 17c) on the distal end of the main carrier device (4), wherein the pivot axes (17a, 17 b; 17c) lie parallel to one another in one plane.

4. The endoscope of claim 1, wherein the endoscope is used in a surgical robotic system.

5. An endoscope according to claim 1, characterized in that both the main carrier device (4) and the additional carrier device (3) are cylindrically formed.

6. A surgical robotic system having at least one robotic arm on which at least one surgical instrument and/or an endoscope for minimally invasive surgery can be disposed, the endoscope having:

a main carrier device (4) which extends from the outside into the body over the entire endoscope length and which has at least one illumination unit (15, 16) and two image recording devices (12a, 13a, 14a, 12b, 13b, 14 b; 12c) at the distal end, wherein the image recording devices (12a, 13a, 14a, 12b, 13b, 14 b; 12c) are each arranged in the same plane in such a way that they can be pivoted out of the main carrier device (4);

a cannula (1) for entering the endoscope into a body; and

an additional carrier device (3) which is arranged on the sleeve (1) and/or the main carrier device (4), wherein the additional carrier device (3) has an additional image recording device (8, 9, 10, 11) on its distal end, which is arranged in a pivotable manner outwards from the additional carrier device (3), and wherein the additional image recording device (8, 9, 10, 11) has an additional illumination unit (10, 11) and at least one additional image sensor (8, 9) which has a monitoring region which comprises two monitoring regions of the image recording device (12a, 13a, 14a, 12b, 13b, 14 b; 12c) of the main carrier device (4),

wherein an image processing unit (25) is provided, which is coupled both to the two image recording devices (12a, 13a, 14a, 12b, 13b, 14 b; 12c) and to the additional image recording device (8, 9, 10, 11), and a visualization unit (27) which displays the 2D image data and/or the 3D image data of the image recording devices (12a, 13a, 14a, 12b, 13b, 14 b; 12c) and/or of the additional image recording device (8, 9, 10, 11),

it is characterized in that the preparation method is characterized in that,

the additional carrier device (3) is directly applied to the main carrier device (4) between the sleeve (1) and the main carrier device (4), and the image recording devices (12a, 13a, 14a, 12b, 13b, 14 b; 12c) are each arranged in a tiltable manner about the pivot axis (17a, 17 b; 17c) and about a further axis of rotation (19) that is orthogonal to the longitudinal extension of the carrier device (4) by means of joints (17a, 17 b; 17c), wherein the rotational movements about the pivot axis (17a, 17 b; 17c) and the axis of rotation (19) are decoupled from one another.

7. The robotic system according to claim 6, characterized in that the additional image sensor (8, 9) has a wide-angle optical arrangement (8) which is arranged in the pivoted-out state near the distal end of the cannula (1).

8. Robot system according to claim 6 or 7, characterized in that two image recording devices (12a, 13a, 14a, 12b, 13b, 14 b; 12c) are each pivotably arranged about a pivot axis (17a, 17 b; 17c) at the distal end of the main carrier device (4), wherein the pivot axes (14a, 14b) lie parallel to each other in one plane.

9. Robot system according to claim 6, characterized in that both the main carrier device (4) and the additional carrier device (3) are cylindrically formed.