Device for removing the vitreous body of an eye, robotic surgical system and method for setting a settable parameter value for at least one operating parameter of a portion of a surgical instrument for removing the vitreous body of an eye

Abstract

The invention relates to device for removing the vitreous body of an eye. The device comprises a surgical instrument having a distal portion which is designed to separate vitreous body pieces from the vitreous body and to suction the vitreous body pieces, and which can be operated with at least one operating parameter having parameter values that can be set by means of a setting device. A tissue response of the retina is detected by a response determination device and forwarded to an open-loop or closed-loop control device in order to create a feedback signal. The invention also relates to a corresponding method.

Description

[0001] Device for removing the vitreous body of an eye, robotic surgical system and method for setting an adjustable parameter value for at least one operating parameter of a portion of a surgical instrument for removing the vitreous body of an eye

[0002] The present invention relates to a device for removing the vitreous body of an eye and a robotic surgical system comprising such a device. Furthermore, the invention relates to a method for setting an adjustable parameter value for at least one operating parameter of a portion of a surgical instrument for removing the vitreous body of an eye.

[0003] Retinal surgery often requires a vitrectomy, i.e., removal of the vitreous humor of the eye. This is performed using a special surgical instrument called a vitrectome. A typical vitrectome comprises a distal section with an outer tube and an inner tube that can be moved against each other. The outer tube has an opening in its peripheral wall through which vitreous tissue can be sucked into the lumen of the tube. The inner tube also has a lumen and is open, for example, at its distal end. Through the open distal end, pieces of the vitreous humor can be sucked into the lumen of the inner tube and drained through the lumen.The inner tube performs a high-frequency back and forth movement between a first position and a second position in the axial direction, closing the opening in the outer tube in the first position and opening it in the second position. During the closing movement, i.e. the movement from the second position to the first position, the inner tube cuts off the part of the vitreous that has been sucked in through the opening of the outer cannula in a guillotine-like manner and finally sucks it out through the lumen of the inner tube. There are also double-edged vitrectomes in which the inner tube moves further beyond the open position into a second closed position, whereby the inner tube also cuts off the part of the vitreous that has been sucked in through the opening of the outer cannula during the movement into the second closed position.Instead of an axial movement, a rotational movement of the inner tube can also occur within the outer tube, in which case the inner tube also has an opening in its peripheral wall. In a first rotational position of the inner tube, this closes the opening in the peripheral wall of the outer tube. In a second rotational position of the inner tube, the opening in its peripheral wall is aligned with the opening in the peripheral wall of the outer tube, so that vitreous tissue can be sucked in. When the inner tube rotates further from this rotational position, the part of the vitreous that has been sucked in through the opening in the peripheral wall of the outer tube is separated and sucked out through the lumen of the inner tube.This variant of the vitrectome can also be designed with two cutting edges if the inner tube rotates further beyond the open position into a second closed position, whereby the inner tube then also cuts off the part of the vitreous body sucked in through the opening of the outer cannula when moving into the second closed position.

[0004] When vitreous tissue is removed near the retina, this process is called shaving. During this shaving, the suction of vitreous tissue into the vitrectome exerts a tensile force on the fibers (collagen fibers) of the vitreous, which can be transferred from the fibers to the retina connected to the vitreous. In the worst case, this can lead to tears or detachments of the retina. Furthermore, the retina can also be directly suctioned into the vitrectome. This can also lead to tears in the retina, detachments of the retina, or even partial loss of the retina. Therefore, shaving places high demands on the surgeon.

[0005] From US 2003 / 0195538 A1, it is known that it is advantageous to increase the frequency of movement of the parts of the vitrectome relative to each other near the retina in order to protect the retina during shaving. From WO 98 / 52502 A1, it is also known that it is advantageous to reduce the amplitude of the back-and-forth movement in the vitrectome near the retina in order to protect the retina.

[0006] Although both increasing the vitrectomy frequency and decreasing the vitrectomy amplitude reduce the risk of retinal damage, there remains a need for improved retinal protection during shaving.

[0007] It is therefore a first object of the present invention to provide a device for removing the vitreous body of an eye and a surgical system with which the protection of the retina can be further improved. Furthermore, a second object of the present invention is to provide a method for adjusting at least the frequency or the amplitude of the movement of a first element of a surgical instrument relative to a second element of the surgical instrument during the removal of the vitreous body of an eye, with which the protection of the retina can be further improved.

[0008] The first object is achieved by a device for removing the vitreous body of an eye according to claim 1 or by a robotic surgical system according to claim 10. The second object is achieved by a method according to claim 11. The dependent claims contain advantageous developments of the invention.

[0009] A device according to the invention for removing the vitreous body of an eye comprises a surgical instrument with a distal section, which is designed to separate pieces of the gas body from the vitreous body and to suction the pieces of the vitreous body, and which can be operated to separate pieces of the gas body from the vitreous body and to suction the pieces of the vitreous body with at least one operating parameter with adjustable parameter values. The at least one operating parameter can include, for example, the strength of the suction of the vitreous tissue or the speed of movement of the distal section of the surgical instrument relative to the retina or the acceleration of the distal section of the surgical instrument or the rotational position of the distal section of the surgical instrument relative to the retina if the distal section is automatically rotatable.If the distal portion of the surgical instrument comprises a first element and a second element, the first element being arranged to be movable relative to the second element, as is the case, for example, with a vitrectome, the at least one operating parameter can include, for example, the frequency of movement of the first element relative to the second element or the amplitude of movement of the first element relative to the second element. Of course, the at least one operating parameter can also include several or all of the aforementioned operating parameters.

[0010] The device also comprises a setting device for setting a parameter value to be set for the at least one operating parameter and a control or regulating device.

[0011] Furthermore, the device comprises a response determination device which is configured to determine a tissue response of the retina to parameter values ​​of the at least one operating parameter and to output it as the determined tissue response to the control or regulating device for controlling or regulating the setting device. The control or regulating device is configured to determine the parameter value to be set as a function of the determined tissue response and to output a control or regulating signal for setting the parameter value to be set to the setting device. Because the response determination device determines the tissue response of the retina to parameter values ​​of the at least one operating parameter, it is possible to determine suitable parameter values ​​for the distal section of the surgical instrument such that the tissue response of the retina remains within the tolerable range, i.e.in an area where there is no risk of retinal tears or detachment.

[0012] The tissue response of the retina is typically a movement of the retina, which can be caused, for example, by the movement of the distal section relative to the retina. But also the suction of vitreous tissue and / or the movement of the first element of the surgical instrument relative to the second element of the surgical element, when the distal section of the surgical instrument comprises a first element and a second element which are arranged so as to be movable relative to one another, and / or the orientation of the distal section of the surgical instrument, i.e. whether its opening points towards the retina or away from the retina, can cause and / or magnify a movement of the retina. The movement of the retina usually results from a force acting on it, which is exerted by the distal section of the surgical instrument on the fibers of the vitreous tissue and transmitted by these to the retina.The strength with which this force, which can particularly be a pulling force, acts on the retina depends, for example, on the distance of the surgical instrument from the retina. Furthermore, the force acting on the retina is greater the larger the volume of vitreous tissue aspirated by the surgical instrument. Increasing the frequency of movement of the first element relative to the second element, for example, results in less time being available for the vitreous tissue to be sucked in, so that only a smaller portion of the vitreous tissue is sucked in. This reduces the force transmitted from the vitreous to the retina. Reducing the suction strength or reducing the amplitude of the movement of the first element relative to the second element has a similar effect.By reducing the amplitude, the size of the opening through which vitreous tissue can be sucked into the surgical instrument can be controlled. If the amplitude of the movement, for example in a vitrectomy described above, is kept so small that only a portion of the opening in the outer wall of the outer tube is exposed at any one time, then only a smaller amount of vitreous tissue can be sucked in than if the entire opening were always exposed. By controlling the amount of vitreous tissue sucked into the surgical instrument, the force transmitted from the vitreous to the retina can be controlled. Setting a suitable orientation of the opening through which the suction occurs can also be used to control the force transmitted from the vitreous to the retina. If the opening points away from the retina, the force transmitted to the retina is lower than if the opening points towards the retina.Likewise, a reduction in the speed or acceleration with which the distal portion of the surgical instrument is moved relative to the retina can lead to a reduction in the force transmitted to the retina. Friction of the vitreous tissue bevels against the distal portion of the surgical instrument can cause the fibers adjacent to the distal portion to be dragged along by the movement or acceleration of the distal portion, which in turn creates a tensile force that can be transmitted to the retina via the fibers.

[0013] The device according to the invention therefore makes it possible to keep the force acting on the retina in the non-critical range in any pose of the distal section of the surgical instrument by controlling or regulating the parameter value for the at least one operating parameter of the distal section of the surgical instrument.

[0014] The response determination device can in particular be configured to take into account at least one of the following information when determining the tissue response of the retina: the pose of the distal section of the surgical instrument with respect to the retina, ie the position and / or the orientation of the distal section of the surgical instrument with respect to the retina, the size of the distal section of the surgical instrument, the material of the distal section of the surgical instrument.

[0015] The control or regulating device is then designed to also take into account, when determining the parameter value to be set, at least the information taken into account by the response determination unit when determining the tissue response.

[0016] The information mentioned concerns variables that influence the strength of the force transmitted to the retina. For example, the force transmitted to the retina is greater the closer the distal portion of the surgical instrument is to the retina; the size of the distal portion determines the surface area where friction can occur; and the material of the distal portion determines its coefficient of friction.

[0017] To determine the tissue response, the response determination device can comprise a prediction device configured to predict the tissue response of the retina based on a model and to output the predicted tissue response as a determined tissue response to the control or regulating device. The model used can, for example, be a tissue model of the vitreous body and the retina, which takes into account biomechanical properties of the vitreous tissue, the retinal tissue, and the interactions between the vitreous tissue and the retinal tissue, as well as between the surgical instrument and the vitreous tissue. Biomechanical properties include, for example,the absolute and / or relative movement possibilities of tissue types or parts of tissue types, the absolute and / or relative movement limits of tissue types or parts of tissue types, the possible speeds at which movements of tissue types or parts of tissue types can occur, etc., as well as the deformability of the various tissue types or parts of tissue types, e.g., elasticity or tear resistance. In particular, individual fibers of the vitreous tissue can also be modeled. The response determination device can thus be implemented in software as part of a device for removing the vitreous body of an eye.

[0018] Additionally or alternatively, the response determination device for determining the tissue response can comprise a sensor device configured to detect the tissue response of the retina to currently set parameter values ​​of the at least one operating parameter. The sensor device can comprise, for example, a camera, a stereo camera, an OCT system (OCT: optical coherence tomography), or another device with which the movement of the retina can be detected. In this case, the response determination device is configured to output the detected tissue response as a determined tissue response to the control or regulating device.This embodiment of the device according to the invention enables the creation of a feedback loop, which in turn makes it possible to counteract with a changed parameter value for the at least one operating parameter when the currently recorded tissue response approaches a critical range. The use of a tissue model of the vitreous body and the retina is not absolutely necessary, but can be advantageous for determining the changed parameter value. In particular, if the determination of the tissue response is repeated often enough, this embodiment of the device according to the invention enables the parameter value for the at least one operating parameter to be controlled such that the tissue response for each pose of the distal section of the surgical instrument relative to the retina remains within a range in which damage to the retina is not to be feared.Alternatively, it would also be possible to trigger events / feedback signals to the overall system or a control system or to the physician (e.g. warning signal, emergency stop, malfunction detection) based on the recorded tissue response of the retina if the recorded tissue response of the retina shows that the tissue response is approaching a critical range.

[0019] If the response determination device comprises both a sensor device for detecting a tissue response and a prediction device, the control or regulating device can be configured to determine a preliminary parameter value to be set on the basis of the predicted tissue response and to correct this parameter value on the basis of the detected tissue response.

[0020] The device according to the invention can also comprise a planning device configured to determine an optimized trajectory of the distal section of the surgical instrument for removing the vitreous body using an eye model. Unlike a tissue model, an eye model is based not only on the biomechanical properties of the vitreous tissue, the retinal tissue, and the interactions between the vitreous tissue and the retinal tissue, and between the surgical instrument and the vitreous tissue, but also on the geometry of the eye. In this way, a surgeon can be supported by suggesting an optimized path for removing the vitreous body, particularly near the retina. The path represented by the trajectory can, for example, be superimposed onto a microscope image.If the surgical instrument is robotically guided by a robotic arm during vitreous removal, the optimized trajectory can also be transmitted to the robotic arm, which then guides the surgical instrument such that the distal section follows the trajectory. The planning device can also be configured to use the eye model to determine an optimized movement speed of the distal section of the surgical instrument and / or an optimized acceleration of the distal section of the surgical instrument along the trajectory and / or an optimized orientation of the distal section of the surgical instrument along the trajectory. This simplifies the process of finding an optimized trajectory along which the risk to the retina is minimized.

[0021] A robotic surgical system according to the invention for removing the vitreous body of an eye comprises a device according to the invention for removing the vitreous body of an eye and a robotic arm for at least partially autonomously guiding the surgical instrument. For example, the robotic surgical system enables the parameter value of the at least one operating parameter, such as the frequency and / or the amplitude of the movement of the first element of the surgical instrument relative to the second element of the surgical instrument, to be automatically adjusted while the surgeon removes the vitreous tissue. It is advantageous if the movement of the retina is detected, and the parameter value of the at least one operating parameter is controlled based on the detected movement of the retina.Furthermore, it may be advantageous for the surgeon to follow a trajectory suggested by the planning device when removing the tracheal tissue, possibly with a suggested movement speed of the distal portion of the surgical instrument and / or with a suggested acceleration of the distal portion of the surgical instrument and / or a suggested orientation of the distal portion of the surgical instrument relative to the retina. If such a trajectory has been determined by the planning device, it is even possible for the robotic system to perform the removal of the vitreous body with a high degree of autonomy, in particular completely autonomously.

[0022] An autonomously or semi-autonomously robotically guided surgical instrument enables, in particular, the control or regulation of the orientation of the opening of the distal section of the surgical instrument in relation to the retina. The control unit understands, through the eye model, how the opening of the distal section of the surgical instrument is oriented relative to the retina. The rotational position of the distal section about its longitudinal axis is then robotically controlled so that the opening points in an optimal direction, e.g., away from the retina. For example, a handheld surgical instrument with a small rotational actuator, which enables robotically controlled adjustment of the rotational position of the distal section, could be used here. Alternatively, a robotic arm with a rotational degree of freedom for the surgical instrument would be conceivable.

[0023] In the method according to the invention for setting an adjustable parameter value for at least one operating parameter of a distal section of a surgical instrument for removing the vitreous body of an eye, wherein the distal section is designed for separating

[0024] gas body pieces from the vitreous body and for suctioning the vitreous body pieces, the distal section is used to separate

[0025] Gas body pieces from the vitreous body and for suctioning the vitreous body pieces with a set parameter value for the at least one adjustable operating parameter. The at least one adjustable operating parameter can, for example, comprise the strength of the suction of the vitreous tissue or the speed of movement of the distal section of the surgical instrument relative to the retina or the acceleration of the distal section of the surgical instrument or the rotational position of the distal section of the surgical instrument relative to the retina if the distal section is automatically rotatable. If the distal section of the surgical instrument comprises a first element and a second element, wherein the first element is arranged to be movable relative to the second element, as is the case, for example,As is the case with a vitrectome, the at least one operating parameter can include, for example, the frequency of the movement of the first element relative to the second element or the amplitude of the movement of the first element relative to the second element. Of course, the at least one operating parameter can also include several or all of the aforementioned operating parameters.

[0026] In the method, a tissue response of the retina to parameter values ​​of the at least one operating parameter is determined, a parameter value to be set for the at least one adjustable operating parameter is determined depending on the determined tissue response, and the parameter value to be set is set. The determined tissue response of the retina can be or include a tissue response predicted using a model. Additionally or alternatively, the determined tissue response of the retina can be or include a tissue response detected by means of a sensor device. In particular, a provisional parameter value to be set can be determined based on the predicted tissue response, which parameter value is then corrected based on the detected tissue response. The corrected provisional parameter value to be set then forms the parameter value to be set.

[0027] The method according to the invention makes it possible to adjust the parameter value of at least one operating parameter of the distal portion of the surgical element such that the tissue response of the retina remains within the tolerable range, i.e., within a range in which tears or detachment of the retina are not to be feared, as has been explained in detail with reference to the device according to the invention and its further embodiments. The advantages of the embodiments of the method presented below also emerge from the explanations of the device according to the invention, to which reference is therefore made.

[0028] In the method, the at least one operating parameter can include, for example, the strength of the suction of the vitreous tissue or the speed of movement of the distal section of the surgical instrument relative to the retina or the acceleration of the distal section of the surgical instrument or the rotational position of the distal section of the surgical instrument relative to the retina if the distal section is automatically rotatable. If the distal section of the surgical instrument comprises a first element and a second element, wherein the first element is arranged to be movable relative to the second element, as is the case, for example, with a vitrectome, the at least one operating parameter can include, for example, the frequency of the movement of the first element relative to the second element or the amplitude of the movement of the first element relative to the second element.Of course, the at least one operating parameter can also comprise several or all of the aforementioned operating parameters.

[0029] In the method, at least one of the following information can be taken into account when determining the tissue response of the retina (103): the pose of the distal section of the surgical instrument (1) with respect to the retina (103), the size of the distal section of the surgical instrument (1), the material of the distal section of the surgical instrument.

[0030] When determining the parameter value to be set, the information taken into account by the response determination unit when determining the tissue response is also taken into account.

[0031] In the method according to the invention, an optimized trajectory of the distal section of the surgical instrument for removing the vitreous body can be determined using an eye model. This trajectory can, for example, be superimposed on a microscope image. If the surgical instrument is robotically guided by a robotic arm during the removal of the vitreous body, the optimized trajectory can also be transmitted to the robotic arm, which then guides the surgical instrument such that the distal section follows the trajectory. The planning device can also be configured to use the eye model to determine an optimized movement speed of the distal section of the surgical instrument along the trajectory and / or an optimized acceleration of the distal section of the surgical instrument and / or an optimized orientation of the distal section of the surgical instrument along the trajectory.This makes it easier to find an optimized trajectory along which the risk to the retina is minimized. As described with reference to the device according to the invention, this can be used to assist a surgeon. Furthermore, it is possible to perform the vitreous removal robotically, either semi-autonomously or with a high degree of autonomy or even completely autonomously.

[0032] Further features, properties and advantages of the present invention will become apparent from the exemplary embodiments described below with reference to the accompanying figures.

[0033] Figure 1 shows a vitrectome as an example of a surgical instrument with a first element and a second element, wherein the first element is arranged to be movable relative to the second element.

[0034] Figure 2 shows the vitrectome of Figure 1 with the second element in a position releasing an opening in the peripheral wall of the vitrectome.

[0035] Figure 3 shows the vitrectome of Figure 1 with the second element in a position closing the opening in the peripheral wall of the vitrectome.

[0036] Figure 4 shows an alternative version of the vitrectome.

[0037] Figure 5 schematically shows an exemplary embodiment of a device for removing the vitreous body of an eye.

[0038] Figure 6 schematically shows a control device for controlling the movement of the first element of the surgical instrument relative to the second element of the surgical instrument.

[0039] A device for removing the vitreous body of an eye is described below with reference to the figures. Figures 1 to 3 show a vitrectome 1 as an example of a surgical instrument according to the invention, having a distal section 3. The distal section 3 extends from a proximal end 7, where it is connected to a handpiece 9, to a distal end 5. The distal section forms a so-called cutter 3. The handpiece 9 contains a drive for the cutter.

[0040] In the present exemplary embodiment, the cutter 3 comprises, as essential components, a first element and a second element, which are arranged movably relative to one another, namely an outer tube 11 and an inner tube 13 arranged movably inside the outer tube 11 along its longitudinal axis (see Figures 2 and 3). The outer tube 11 is closed at the distal end 5 of the cutter by an end wall 15 and has an opening 17 in its peripheral wall in the region of the distal end 5 of the cutter.

[0041] The inner tube 13 is open at its distal end 14 and has a lumen 19, which is connected in the region of the handpiece 9 to a suction device, of which only a suction hose 21 leading out of the handpiece 9 is shown in Figure 1. In addition, the inner tube 13 is connected to an actuator arranged inside the handpiece 9, which enables the inner tube 13 to be moved back and forth within the outer tube 11 along the common longitudinal axis, as indicated by a double arrow in Figure 2. During this back and forth movement, the inner tube 13 can be brought into a first position with respect to the outer tube 11, in which it completely exposes the opening 17 in the peripheral wall of the outer tube 11. This position of the inner tube 13 is shown in Figure 2.Furthermore, the inner tube 13 can be brought into a second position by means of the reciprocating movement with respect to the outer tube 11, in which position it completely closes the opening 17 in the peripheral wall of the outer tube 11, as shown in Figure 3. The outer diameter of the inner tube 13 is selected such that only a minimal circumferential gap remains between the outer surface of the inner tube 13 and the inner surface of the outer tube 11, which gap is just large enough to allow the reciprocating movement of the inner tube 13. During operation of the cutter, the inner tube 13 moves rapidly back and forth at a frequency of typically 20 Hz or more, although the frequency can be up to 16,000 Hz.During such a back-and-forth movement, when the inner tube 13 is in the position shown in Figure 2 with respect to the outer tube 11, vitreous substance is sucked in with the aid of the suction device through the opening 17 in the peripheral wall of the outer tube 11 into the space 22 formed between the end wall 15 of the outer tube 11 and the open distal end 14 of the inner tube 13. As the inner tube 13 moves into the position shown in Figure 3, the vitreous substance sucked into the space 22 is separated from the rest of the vitreous substance in a guillotine manner and sucked out through the lumen 19 of the inner tube 13. In this way, the vitreous substance in the eye is crushed and removed with the aid of the cutter.

[0042] Instead of an axial back and forth movement of the inner tube 13 in relation to the outer tube 11, a rotational movement of the inner tube 13 can also take place within the outer tube 11, as shown in Figure 4. In this case, the inner tube 11 has an opening 23 in its peripheral wall instead of an opening at its distal end. In a first rotational position of the inner tube 13, it closes the opening 17 in the peripheral wall of the outer tube 11. In a second rotational position of the inner tube 13, the opening 23 in the peripheral wall of the inner tube 13 is aligned with the opening 17 in the peripheral wall of the outer tube 11, so that vitreous tissue can be sucked in.When the inner tube 13 continues to rotate from this rotational position, the part of the vitreous body sucked in through the opening 17 in the peripheral wall of the outer tube 11 and the opening 23 in the peripheral wall of the inner tube 13 is separated and sucked out through the lumen 19 of the inner tube 13.

[0043] If the opening of the inner tube 13 is located in its peripheral wall, the vitrectome 1 can also be designed as a double-edged vitrectome 1. In this case, the outer tube 11 is longer than shown in Figures 2 to 4, so that the inner tube 13 can be brought by a linear movement toward the distal end 5 of the outer tube 11 from a position in which its peripheral wall closes the opening 17 in the outer tube 11 to a position in which the opening 17 in the outer tube 11 and the opening in the inner tube 13 are aligned. With a further linear movement in the same direction, the inner tube 13 can then move further towards the distal end 5 of the outer tube 11 until a second closed position is reached, in which the peripheral wall of the inner tube 13 closes the opening 17 in the outer tube 11 again.During the opposite movement, there are then also two positions of the inner tube 13 which close the opening 17 in the outer tube 11.

[0044] An exemplary embodiment of a device for removing the vitreous body of an eye is described below with reference to Figure 4. The exemplary embodiment shows a device that enables automated removal of the vitreous body, or at least assisted removal of the vitreous body.

[0045] The device for removing the vitreous body 101 of an eye 100 comprises a vitrectome 1, which can be, for example, a vitrectome as described with reference to Figures 1 to 4. In the present exemplary embodiment, this is attached to a robotic arm 25, which is controllable by means of a control or regulating device 27. The control or regulating device 27 is also designed to supply an adjustment device 28 of the vitrectome 1 with control or regulating signals in order to control or regulate the frequency with which the inner tube 13 of the vitrectome 1 is moved relative to the outer tube 11. The device for removing the vitreous body 101 of the eye 100 further comprises a surgical microscope 29, which in the present exemplary embodiment is a digital surgical microscope with a stereo camera 30a, 30b.In the present exemplary embodiment, an OCT system 31 is also integrated into the surgical microscope 29. The functionality of an OCT system is sufficiently known to a person skilled in the art and will therefore not be explained further here. Furthermore, the device for removing the vitreous body 101 comprises a human-machine interface 31, which is a PC in the present exemplary embodiment. Parameters can be entered into the control or regulating device 27 or parameters present in the control or regulating device 27 can be changed via the human-machine interface 31.

[0046] During the removal of the vitreous body 101, the stereo camera 30a, 30b records a 3D video stream of the eye 100, from which, in the present exemplary embodiment, an evaluation device 35 determines the position and orientation of the distal end 5 of the vitrectome 1 relative to the retina 103 of the eye 100 in a time-resolved manner. Furthermore, the evaluation device 35 also determines the movement speed of the vitrectome 1 relative to the retina 103 based on the 3D video. In the present exemplary embodiment, this evaluation device 35 is integrated into the control and regulating device 27. However, it can also be a standalone unit or integrated into the PC 33.

[0047] Furthermore, the evaluation device 35 can determine retinal movements from the 3D video stream. Retinal movements can occur, in particular, because the suction and cutting of the vitreous tissue by the vitrectome 1 exerts forces on the vitreous tissue still remaining in the eye 100, which are transferred from the vitreous tissue to the retina 103.

[0048] The tissue response can be determined alternatively or additionally using the OCT system 31. The OCT system 31 can acquire an A-scan of the retina 103 (depth scan at a specific point on the retina), a B-scan of the retina 103 (depth scan along a line running on the retina), or a C-scan of the retina 103 (depth scan at points on a surface grid on the retina). If the scans are acquired with time resolution, they can be used to detect movement of the retina 103. B-scans and C-scans are advantageous in this case, as they also allow the propagation of wave-like movements in the retina 103 to be captured. In addition, the depth scans make it possible to detect changes in the thickness of the retinal tissue, which can be used to determine stretching and compression of the retinal tissue.Furthermore, it is generally possible to use a C-scan to determine the position and orientation of the distal end 5 of the vitrectome 1 if it is located near the retina 103 and the scan also covers areas above the retinal tissue. If the C-scan is performed with sufficient temporal resolution, the movement speed of the vitrectome can also be determined.

[0049] Alternatively or in addition to the OCT system 31 integrated into the surgical microscope 29, an OCT system integrated into the vitrectome 1 can also be used. With a high sampling rate for the distance between the vitrectome 1 and the retina 103, the OCT system integrated into the vitrectome 1 can capture the tissue response to movements of the cutter 3 with particular precision.

[0050] In addition, it is possible to additionally or alternatively use special movements of the cutter 3 (axial / lateral) that go beyond the actual cutter movements, and to use the resulting tissue response of the retina 103 to infer critical conditions, etc., or to adapt the tissue model or the eye model.

[0051] In the present exemplary embodiment, the control or regulating device 27 contains an eye model 37. The eye model 37 represents a number of properties of the eye 100 and their interactions with one another. In particular, the eye model 37 represents the geometric properties of the eye 100, i.e., the geometric shape of the eye 100, the dimensions of the eye 100, such as the axial length of the eye 100, the position of the eye, and the orientation of the eye. In addition to the geometric properties of the eye 100, the eye model 37 represents anatomical properties of the eye 100 and biomechanical properties of the eye 100.As anatomical properties of the eye 100, the eye model 37 can, in particular, describe at least one of the following properties: the depth of the anterior chamber, the curvature and thickness of the lens, the curvature and thickness of the cornea, the chamber angle, the course of blood vessels in the eye 100, the course of nerve pathways in the eye 100, the curvature of the eyeball in the region of the retina 103, and the thickness of the retina 103. As biomechanical properties of the eye 100, the eye model 37 in the present exemplary embodiment represents at least the possible movements of the vitreous body 101 and the retina 103 relative to one another. Furthermore, it can represent the limits of these possible movements, the possible speeds at which these movements can occur, etc.Furthermore, in the present exemplary embodiment, the eye model 37 represents the elasticity and tear resistance of at least the vitreous tissue and the retinal tissue as biomechanical properties of the eye 100. In particular, the mechanical properties of individual fibers of the vitreous tissue can also be modeled. Simple models can also be used, where, for example, it is assumed that a fiber runs along the shortest distance between the tool and the retina. According to the model, this fiber has a certain elasticity and is moved a certain distance on the side of the opening 17 of the cutter 3, whereby it experiences an overall relative stretch, which then acts as tension on the retina and thus exerts a force on the retina.For longer fibers or fibers that have not yet been prestressed, the strain would be lower than for shorter or already prestressed fibers, so that for longer fibers or fibers that have not yet been prestressed, lower stresses would also occur. With such a simple model, simple worst-case estimates can be made, which can serve as a basis for control. Furthermore, it can represent the elasticity and tear resistance of other tissue types of the eye 100, as well as other tissue properties that influence the deformability of the various tissue types. In order to represent the biomechanical properties of the eye 100, the eye model 37 in the present exemplary embodiment comprises a finite element model, with which a dynamic model of the eye 100 can be realized.

[0052] The eye model 37 can be a patient-specific eye model. A patient-specific eye model 37 is usually created preoperatively; depending on the type of surgery, fundus cameras, MRI systems, CT systems, etc. can be used. It is also possible to update the eye model 37 using intraoperatively recorded stereoscopic images of the eye 100 and / or scans acquired intraoperatively with the OCT system 31, i.e., to update the properties stored in the eye model 37 based on the properties of the eye 100 acquired intraoperatively.

[0053] The properties of the eye 100 represented by the eye model 37 can influence each other. For example, a force acting on the vitreous body 101 can lead to tensions or compressions in the retina 103, which in turn influence the thickness of the retina 103 in the tensioned or compressed retinal areas and, in the worst case, lead to tears in the retinal tissue or in the blood vessels of the retina 103. Based on the biomechanical properties represented by the eye model 37, the control or regulating device 27 can therefore determine the interaction between the cutter 3 and the vitreous tissue, and based on the determined interaction, in turn determine the forces acting on the vitreous tissue. Furthermore, the control or regulating device 27 can determine the transmission of the forces exerted by the cutter 3 on the vitreous tissue to the retinal tissue in order to determine the forces acting on the retina 103 due to the cutter 3.Using the eye model 37, the control or regulating device 27 can thus predict the tissue response of the retina 103 to the operation of the cutter 3 with a specific frequency of movement of the inner tube 13 relative to the outer tube 11 and a specific amplitude of this movement. In this sense, the eye model 37 of the control or regulating device 27 can be viewed as a response determination device configured to determine a tissue response of the retina 103 by prediction.

[0054] In the present exemplary embodiment, the prediction of the tissue response of the retina is carried out depending on the pose, i.e., the position and orientation of the cutter 3 with respect to the retina 103. The pose of the cutter 3 can be determined, for example, from the stereoscopic images recorded with the stereo camera 30a, 30b or from the 3D video stream recorded with the stereo camera 30a, 30b. When using the robotic arm 25 to hold the vitrectome 1, the pose of the cutter 3, i.e., the position and orientation of the cutter 3, can also be approximately determined from the position of the robotic arm 25. If the pose of the cutter 3 is recorded with time resolution, the movement speed of the cutter 3 and the acceleration of the cutter 3 can also be determined. In addition to the pose of the cutter 3, the size of the cutter 3 and / or the material of the cutter 3 can also be taken into account when predicting the tissue response.

[0055] In the present exemplary embodiment, the control and regulating device 27 determines predictions of the tissue response of the retina 103 for a plurality of combinations of frequencies and amplitudes of the movement. From these predictions, it then determines an optimized frequency and / or an optimized amplitude of the movement such that the tissue response does not exceed a predetermined level, i.e., that no forces damaging the retina 103 act on the retina 103. Based on the optimized frequency and / or the optimized amplitude, the control or regulating device 27 then generates a control signal and outputs it to the setting device 28 of the vitrectome 1, which sets the corresponding frequency and the corresponding amplitude on the vitrectome 1.Because the control or regulating device 27 is able to adjust the frequency and / or the amplitude of the movement of the inner tube 13 relative to the outer tube 11 of the vitrectome 1 based on the eye model in such a way that damage to the retina 103 during removal of the vitreous body 101 can be avoided, a vitrectomy can be performed that is gentle on the patient.

[0056] The prediction of the tissue response of the retina 103 and the determination of the optimized frequency and / or the optimized amplitude as well as the output of the control signal to the adjustment device 28 of the vitrectome 1 can in particular be repeated at certain time intervals, wherein the time intervals can depend on the movement speed of the vitrectome 1 with respect to the retina and / or on the distance of the vitrectome 1 with respect to the retina 103 and / or on the orientation of the vitrectome 1 with respect to the retina 103. For example, in the case of a rapid movement of the vitrectome 1 with respect to the retina 103 or a short distance between the vitrectome 1 and the retina 103 or an opening of the vitrectome 1 directed towards the retina 103, shorter time intervals are useful than in the case of a slow movement or a large distance or an opening of the vitrectome 1 directed away from the retina 103.The described type of control of the frequency and / or the amplitude of the vitrectome 1 enables semi-autonomous support of a surgeon during the removal of the vitreous body 1 .

[0057] Additionally or alternatively, the orientation of the cutter 3, in particular of the opening 17 in the outer tube 11, can be controlled automatically, for example such that the opening 17 always points away from the retina 103. To assist the surgeon with a hand-held vitrectome 1, the cutter 3 can be rotatably mounted on the handpiece 9 at its distal end 7 in a motor-driven manner. The control and regulating device 27 then controls or regulates the rotational position of the cutter 3. If the vitrectome 1 is guided by the robotic arm 25, the latter can have a degree of freedom that enables rotation of the vitrectome 1 about the longitudinal axis of the cutter 3.

[0058] Further support for the surgeon is possible if the control or regulating device 27 also comprises a planning device 39, which, based on the eye model 37, determines an optimized trajectory for removing the vitreous body 101 such that the forces acting on the retina 103 during the vitrectomy are minimized. During the vitrectomy, the surgeon typically uses the surgical microscope 29 to visualize the vitrectome 1 and the retina 103. The trajectory determined by the planning device 39 can then be superimposed, for example, as an overlay image into the image acquired with the surgical microscope 29, so that the surgeon can follow the superimposed trajectory with the distal end 5 of the vitrectome 1.The planning device 39 can also determine an optimized speed of the vitrectome 1 with respect to the retina 103 and / or an optimized orientation of the vitrectome 1 with respect to the retina 103 and appropriately display it in the overlay image. For example, the orientation of the vitrectome 1 can be represented by an arrow indicating the direction in which the opening 17 in the outer tube 11 of the vitrectome 1 should be directed. The movement speed along the trajectory can be indicated to the surgeon, for example, by the color representation of the trajectory changing if the movement deviates by more than a certain amount from the optimized movement speed. Different colors can also be used, for example, one color for a movement that is too slow and another color for a movement that is too fast.

[0059] In the described exemplary embodiment, the evaluation device 35, together with the stereo camera 30a, 30b and / or together with the OCT system 31, can also be regarded as a response determination device, with which a detected or measured tissue response of the retina 103 to the position and / or orientation and / or movement speed of the distal end 5 of the vitrectome 1 during removal of the vitreous body 101 can be determined. Instead of a predicted tissue response, the control signal for the adjustment device 28 of the vitrectome 1 can then be determined based on a measured tissue response. Alternatively, it is possible to first predict a tissue response based on the eye model 37, which is then corrected based on the measured tissue response. In this way, the tissue response used to generate the control signal can be more precisely adapted to the actual conditions currently present in the eye 100.

[0060] In the exemplary embodiment described so far, the control or regulating device 27 fulfilled the function of a control device. However, it can also fulfill the function of a regulating device that regulates the frequency and / or amplitude of the inner tube 13 of the vitrectome 1 relative to the outer tube 11 of the vitrectome 1. The function as a regulating device is described below using the flowchart shown in Figure 6.

[0061] To control the frequency and / or amplitude of the movement of the inner tube 13 of the cutter 3 relative to the outer tube 11 of the cutter 3, in the present exemplary embodiment, an initial tissue response of the retina 103 is specified, on the basis of which an initial frequency and an initial amplitude of the movement of the inner tube 13 relative to the outer tube 11 as well as an initial orientation of the cutter 3 are determined (step S1 in Figure 6). The initial tissue response of the retina 103 can be a fixed, predetermined tissue response, or it can be determined based on the eye model 37, as previously described in the context of the control. Based on the initial frequency and the initial amplitude, a control signal for the adjustment device 28 of the vitrectome 1 is then determined in step S2 and output to the adjustment device 28 of the vitrectome 1 in step S3.As soon as the cutter 3 of the vitrectome 1 is operated at the initial frequency, the initial amplitude, and the initial orientation of the cutter 3, the actual tissue response of the retina 103 is measured in step S4 using the stereo camera 30a, 30b and / or the OCT system 31, and in step S5, the difference between the measured actual tissue response and the initial tissue response is calculated. In step S6, it is then checked whether the difference calculated in step S5 exceeds a predetermined threshold value. If this is not the case, the method returns to step S4, where the current actual tissue response is measured again.If, however, the difference exceeds the predefined threshold, the method proceeds to step S7 within a feedback loop, where an updated tissue response is determined based on the tissue response previously used in the method and the difference. This updated tissue response then replaces the previously used tissue response when determining the control signal in step S2. When the feedback loop is run for the first time, the previously used tissue response is the initial tissue response.

[0062] With the described control, which is typically continued until the vitrectomy is completed, a particularly precise adjustment of the frequency and / or the amplitude of the movement of the inner tube 13 of the cutter 3 relative to the outer tube 11 of the cutter 3 and / or the orientation of the cutter 3 can be carried out, so that a particularly gentle removal of the vitreous body 101 is possible, in particular near the retina 103.

[0063] The control and regulation methods described in the context of the exemplary embodiments enable at least partially autonomous support of a surgeon during a vitrectomy. If an optimized trajectory and, ideally, also an optimized movement speed and orientation of the cutter 3, as well as, if necessary, an optimized acceleration of the cutter, are determined, it is also possible to further increase the degree of autonomy, up to and including a fully autonomous vitrectomy, provided the robotic arm 25 has the necessary degrees of freedom and the necessary precision in control and regulation.

[0064] The present invention has been described in detail using exemplary embodiments for illustrative purposes. However, one skilled in the art will recognize that deviations from these exemplary embodiments are possible within the scope of the present invention. Therefore, the present invention is not intended to be limited by the exemplary embodiments, but only by the appended claims.

[0065] List of reference symbols

[0066] I Vitrectome

[0067] 3 cutters

[0068] 5 distal end

[0069] 7 proximal end

[0070] 9 Handpiece

[0071] II outer tube

[0072] 13 Breaking Inside

[0073] 14 open distal end

[0074] 15 Front wall

[0075] 17 Opening

[0076] 19 lumens

[0077] 21 Suction hose

[0078] 23 Opening

[0079] 25 robotic arm

[0080] 27 Control and regulation device

[0081] 28 Adjustment device

[0082] 29 Surgical microscope

[0083] 30a, b stereo camera row

[0084] 31 OCT system

[0085] 33 PC

[0086] 35 Evaluation device

[0087] 37 Eye model

[0088] 39 Planning facility

[0089] 100 eyes

[0090] 101 Vitreous Body

[0091] 103 Retina

[0092] 51 Predetermination of an initial tissue response

[0093] 52 Determination of a control signal

[0094] 53 Output of the control signal

[0095] 54 Measurement of the actual tissue response

[0096] 55 Difference formation 56 Checking whether the difference exceeds a specified threshold

[0097] 57 Determination of an updated tissue response

Claims

Patent claims 1. A device for removing the vitreous body (101) of an eye (103), comprising: a surgical instrument (1) with a distal section (3) which is designed to separate gas body pieces from the vitreous body (101) and to suction the vitreous body pieces, and which is operable to separate gas body pieces from the vitreous body and to suction the vitreous body pieces with at least one operating parameter with adjustable parameter values; a setting device (28) for setting a parameter value to be set for the at least one operating parameter; and a control or regulating device (27);characterized in that a response determination device (30a, 30b, 31, 35, 37) is provided which is configured to determine a tissue response of the retina (103) to parameter values ​​of the at least one operating parameter and to output it as a determined tissue response to the control or regulating device (27) for controlling or regulating the setting device (28), and the control or regulating device (27) is configured to determine the parameter value to be set as a function of the determined tissue response and to output a control or regulating signal for setting the parameter value to be set to the setting device (28); 2. Device according to claim 1, characterized in that the distal section (3) of the surgical instrument (1) comprises a first element (13) and a second element (11), wherein the first element (13) is arranged to be movable relative to the second element (11) and the at least one operating parameter comprises at least one of the following operating parameters: Frequency of movement of the first element (13) relative to the second element (11); Amplitude of the movement of the first element (13) relative to the second element (11).

3. Device according to claim 1 or claim 2, characterized in that the at least one operating parameter comprises at least one of the following operating parameters: Rotational position of the distal section (3) of the surgical instrument (1) relative to the retina (103), if the distal section is automatically rotatable; Movement speed of the distal portion (3) of the surgical instrument (1) relative to the retina (103); the acceleration of the distal portion (3) of the surgical instrument (1); Strength of suction of the vitreous tissue.

4. Device according to one of claims 1 to 3, characterized in that the response determination device (30a, 30b, 31, 35, 37) is designed to take into account at least one of the following information when determining the tissue response of the retina (103): the pose of the distal section (3) of the surgical instrument (1) in relation to the retina (103), the size of the distal section (3) of the surgical instrument (1), the material of the distal section (3) of the surgical instrument (1), and the control or regulating device (27) is designed to also take into account at least the information taken into account by the response determination unit (30a, 30b, 31, 35, 37) when determining the tissue response when determining the parameter value to be set.

5. Device according to one of claims 1 to 4, characterized in that the response determination device (30a, 30b, 31, 35, 37) for determining the tissue response comprises a prediction device (37) which is designed to predict the tissue response of the retina (103) using a model (37) and to output the predicted tissue response as a determined tissue response to the control or regulating device (27).

6. Device according to one of claims 1 to 5, characterized in that the response determination device (30a, 30b, 31, 35, 37) for determining the tissue response comprises a sensor device (30a, 30b, 31) which is designed to detect the tissue response of the retina (103) to currently set parameter values ​​of the at least one operating parameter and to output the detected tissue response as a determined tissue response to the control or regulating device (27).

7. Device according to claim 5 and claim 6, characterized in that the control or regulating device (27) is designed to determine a provisional parameter value to be set on the basis of the predicted tissue response and to correct this on the basis of the detected tissue response, the corrected provisional parameter value to be set then forming the parameter value to be set.

8. Device according to one of claims 1 to 7, characterized in that it also comprises a planning device (39) which is designed to determine, on the basis of an eye model (37), an optimized trajectory of the distal section (3) of the surgical instrument (1) for the removal of the vitreous body (101).

9. Device according to claim 8, characterized in that the planning device (39) is also configured to determine, on the basis of the eye model (37), an optimized movement speed of the distal section (3) of the surgical instrument (1) along the trajectory and / or an optimized acceleration of the distal section (3) of the surgical instrument (1) and / or an optimized orientation of the distal section (3) of the surgical instrument along the trajectory.

10. Robotic surgical system for removing the vitreous body (101) of an eye (100) with a device according to one of claims 1 to 9 and a robotic arm (25) for at least partially autonomously guiding the surgical instrument (1).

11. A method for setting an adjustable parameter value for at least one operating parameter of a distal section (3) of a surgical instrument (1) for removing the vitreous body (101) of an eye (103), wherein the distal section (3) is designed to separate pieces of gas body from the vitreous body (101) and to suction the pieces of vitreous body, and is operated to separate pieces of gas body from the vitreous body (1019') and to suction the pieces of vitreous body with a set parameter value for the at least one adjustable operating parameter, characterized in that a tissue response of the retina (103) to parameter values ​​of the at least one operating parameter is determined, a parameter value to be set for the at least one adjustable operating parameter is determined as a function of the determined tissue response, and the parameter value to be set is set.

12. The method according to claim 11, characterized in that the distal portion (3) of the surgical instrument (1) comprises a first element (13) and a second element (11), wherein the first element (13) is arranged to be movable relative to the second element (11) and the at least one operating parameter comprises at least one of the following operating parameters: Frequency of movement of the first element (13) relative to the second element (11); Amplitude of the movement of the first element (13) relative to the second element (11).

13. The method according to claim 11 or claim 12, characterized in that the at least one operating parameter comprises at least one of the following operating parameters: Rotational position of the distal section (3) of the surgical instrument (1) relative to the retina (103), if the distal section is automatically rotatable; Movement speed of the distal portion (3) of the surgical instrument (1) relative to the retina (103); the acceleration of the distal portion (3) of the surgical instrument (1); Strength of suction of the vitreous tissue.

14. Method according to one of claims 11 to 13, characterized in that when determining the tissue response of the retina (103) at least one of the following information is taken into account: the pose of the distal section (3) of the surgical instrument (1 ) with respect to the retina (103), the size of the distal section (3) of the surgical instrument (1 ), the material of the distal section (3) of the surgical instrument, and when determining the parameter value to be set, the information taken into account when determining the tissue response by the response determination unit (30a, 30b, 31, 35, 37) is also taken into account.

15. The method according to any one of claims 11 to 14, wherein the determined tissue response of the retina (103) is or comprises at least one of the following tissue responses: a tissue response predicted using a model (37), a tissue response detected by means of a sensor device (30a, 30b, 31).

16. The method according to claim 15, wherein a preliminary parameter value to be adjusted is determined on the basis of the predicted tissue response and the preliminary parameter value to be adjusted is corrected on the basis of the detected tissue response and the corrected preliminary parameter value to be adjusted then forms the parameter value to be adjusted.

17. Method according to one of claims 11 to 16, in which an optimized trajectory of the distal portion (3) of the surgical instrument (1) for removing the vitreous body (101) is determined using an eye model (37).

18. The method according to claim 17, in which an optimized movement speed of the distal section (3) of the surgical instrument (1) along the trajectory and / or an optimized acceleration of the distal section (3) of the surgical instrument (1) and / or an optimized orientation of the distal section (3) of the surgical instrument (1) along the trajectory is determined based on the eye model (37).

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