Surgical Systems

Abstract

The present disclosure provides a surgical system for treating an anatomical structure according to a plurality of target planes and / or axes, the system comprising: a robotic device (1) comprising an end effector (2) defining a current plane or axis; and an actuation unit (11) coupled to the end effector (2); a tracking unit (3) configured to determine a pose of the current plane or axis; and a control unit coupled to the tracking unit, the control unit configured to control the actuation unit (11) to align the current plane or axis of the end effector (2) with a respective one of the plurality of target planes and / or axes to treat the anatomical structure, the robotic device having at least the following modes: a working mode, in which treatment is performed by the actuation unit; and a standby mode, in which no procedure is being performed with the end effector constrained to one target plane or axis by the robotic device, and a standby mode, in which no procedure is being performed and the actuation unit is operable to move the end effector in alignment with another target plane or axis, wherein the control unit is further configured to (a) determine that the robotic device is in the standby mode, (b) detect a trigger force applied to the end effector and / or the actuation unit in at least one first direction, and (c) as a result of determining (a) and detecting (b), trigger a position change of the end effector by the actuation unit to align the current plane or axis with the next target plane or axis.

Description

[Technical field]

[0001] The present disclosure relates to surgical systems including robotic devices and methods for triggering position changes of such robotic devices. [Background technology]

[0002] Some surgical procedures require performing multiple steps in which anatomical structures are manipulated.

[0003] For example, total knee arthroplasty usually requires cutting both the femoral and tibial epiphysis to remove damaged bone and cartilage and to install the artificial knee joint, and for that purpose the surgeon must make five or more cuts to the femur and one or more cuts to the tibia by using an oscillating saw through a cutting block.

[0004] 1 is a schematic perspective view of a knee intended to receive a knee prosthesis including a femoral component FC and a tibial component TC. In general, the cuts made on the femur F are a distal cut along a plane F1, an anterior cut along a plane F2, a posterior cut along a plane F3, and an anterior chamfer F4 and a posterior chamfer F5 connecting the distal face to the anterior and posterior faces, respectively. A cut of the tibia T along a plane T1 must be made.

[0005] To help surgeons perform all these aspects accurately and in a short period of time, robotic systems have been developed.

[0006] For example, document WO2018 / 103945 teaches a robotic system comprising an electric actuation unit, a planar mechanism having a first end attached to a terminal segment of the actuation unit, a second end fixedly attached to an end effector, which is a saw. The saw comprises a body, a saw blade movable relative to the body, and a handle configured to be gripped by a surgeon to perform the cut. The robotic system also comprises trackers (not shown) attached to the saw and the patient, respectively, to determine in real time the relative positions of the saw and the bone to be cut, as well as a control unit configured to compensate for small movements from the patient or the surgeon to maintain alignment of the saw blade with a given plane where the cut needs to be made. Figures 2A-2F show perspective views of such a robotic device 1 during the performance of a tibial cut, a distal cut, an anterior cut, a posterior cut, an anterior chamfer cut, and a posterior chamfer cut, respectively.

[0007] Control of the end effector position to perform each cutting step can usually be defined as a sequence of the three following steps performed in a loop: Phase 1: The robotic device maintains the cutting position before and during cutting; the robotic device does not deviate from the desired cutting position unless the bone cutting is complete; Phase 2: The cut is completed; the robotic device waits to receive instructions to move to the next cut location; meanwhile, the robotic device typically maintains the position of the end effector at the previous cut location; Phase 3: The robotic device displaces the end effector to the next cutting position, typically after receiving a command from the user for safety reasons.

[0008] To trigger the change from stage 2 to stage 3, the user may have to use a button provided on the end effector or robotic device, i.e. a foot switch, or a virtual button integrated into the software graphic user interface and displayed on a touch screen.

[0009] This triggering step may require the user to search for the foot switch in an invisible zone, remove the user's hands from the end effector, and / or direct another person to activate the robotic device, which can be time-consuming, disruptive to the user's workflow, and frustrating for the user. Summary of the Invention [Means for solving the problem]

[0010] It is therefore desirable to have a system and method for triggering position changes in a robotic device that is more ergonomic for a user.

[0011] An embodiment is a surgical system for treating an anatomical structure according to multiple target planes and / or axes, comprising: 1. A robotic device comprising: an end effector that defines a current plane or axis; an actuation unit coupled to the end effector; A robotic device comprising: a tracking unit configured to determine a current plane or axis pose; a control unit coupled to the tracking unit, the control unit configured to control the actuation unit to align a current plane or axis of the end effector with a respective one of a plurality of target planes and / or axes to treat an anatomical structure; Equipped with The robotic device must be in at least the following modes: A working mode, in which the procedure is performed with the end effector constrained to one target plane or axis by the actuation unit; and a standby mode, in which no treatment is being performed and the actuation unit is operable to move the end effector in alignment with another target plane or axis; It can operate with The control unit (a) determining that the robotic device is in a standby mode; (b) detecting a trigger force applied to the end effector and / or the actuation unit in at least one first direction; (c) triggering, as a result of (a) determining and (b), a change in position of the end effector by the actuation unit to align the current plane or axis with the next target plane or axis; It is further composed of The present invention relates to a surgical system.

[0012] The system makes this triggering step easier and faster, since the user can apply the triggering force directly to the robotic device in front of it.

[0013] In some embodiments, the end effector comprises at least one of a cutting tool, such as a saw, a burr or drill, a cutting guide, and a guiding tool.

[0014] In some embodiments, the tracking unit comprises a tracker fixedly attached to the end effector and / or the actuation unit.

[0015] An embodiment is a method for triggering a position change of a robotic device for treating an anatomical structure according to a plurality of target planes and / or axes, the robotic device comprising an end effector defining a current plane or axis and an actuation unit coupled to the end effector, the robotic system being configured to operate in at least the following modes: A working mode, in which the procedure is performed with the end effector constrained to one target plane or axis by the actuation unit; and a standby mode, in which no treatment is being performed and the actuation unit is operable to move the end effector in alignment with another target plane or axis; 1. A method operable to (a) determining that the robotic device is in a standby mode; (b) detecting a trigger force applied to the end effector and / or the actuation unit in at least one first direction; (c) triggering a position change of the end effector by the actuation unit as a result of the determination and detection made in steps (a) and (b) in order to align the end effector with a next target plane or axis; The present invention relates to a method comprising the steps of:

[0016] The trigger force may include at least one of a linear force and a torque.

[0017] In some embodiments, step (b) includes sensing a current value in at least one servo motor of the actuation unit that is greater than a first threshold value.

[0018] In some embodiments, step (b) includes sensing a displacement of the end effector greater than a second threshold, the displacement of the end effector being sensed based on tracking data of the tracking unit.

[0019] In some embodiments, step (b) comprises detecting a series of external linear forces and / or torques applied to the end effector and / or the actuation unit.

[0020] In some embodiments, the end effector comprises a powered tool including a trigger, and step (b) further comprises detecting pressure on the trigger while the tool is in the off state.

[0021] In some embodiments, the change in position of the end effector is substantially in accordance with a first direction.

[0022] In some embodiments, the method may include stopping the triggered movement of the robotic device as a result of detecting an external force different from the trigger force.

[0023] In some embodiments, step (a) includes determining a position of the end effector relative to the anatomical structure using medical images and / or anatomical landmarks.

[0024] In some embodiments, step (b) further comprises sensing a duration for which the external force is applied, and comparing the sensed duration to a threshold duration.

[0025] In some embodiments, in step (c), the control unit triggers a displacement of the end effector (2) with the determined offset amplitude in the first direction, which offset is cancelled when the trigger force is released. [Brief description of the drawings]

[0026] Further embodiments and advantages are described in the following detailed description, with reference to the accompanying drawings. [Figure 1] 1 is a schematic diagram illustrating the cuts made to the femur and tibia to implant a knee prosthesis; FIG. [Figure 2A] FIG. 13 is a perspective view of a robotic device performing a tibial cut. [Figure 2B] FIG. 13 is a perspective view of a robotic device performing a distal cut. [Figure 2C] FIG. 13 is a perspective view of a robotic device performing an anterior cut. [Figure 2D] FIG. 13 is a perspective view of a robotic device performing a posterior cut. [Figure 2E] FIG. 13 is a perspective view of a robotic device performing a front chamfer cut. [Figure 2F] FIG. 13 is a perspective view of a robotic device performing a back chamfer cut. [Diagram 3] FIG. 1 illustrates a perspective view of a surgical system, in accordance with an embodiment. [Figure 4] FIG. 1 illustrates a perspective view of a robotic device, according to an embodiment. [Diagram 5] FIG. 1 is a flow chart diagram of a method for triggering a position change of a robotic device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] The robotic device comprises a base, an end effector defining a current plane or axis, and a motorized actuation unit coupled to the end effector for moving the end effector relative to the base.

[0028] In some embodiments, the end effector can be a bone cutting tool, such as a saw, a burr, or a drill. If the tool is a surgical saw, the end effector defines a current plane, which is the plane in which the saw blade oscillates. If the tool is a burr or drill, the end effector defines a current axis, which is the longitudinal axis of the burr or drill.

[0029] In other embodiments, the end effector may include a cutting guide, which is a rigid block with at least one through aperture in the form of a slot (defining the current plane) or a cylindrical hole (defining the current axis) configured to guide a freely movable bone cutting tool by the user according to the current plane or axis.

[0030] In other embodiments, the end effector may include a guiding tool to guide an implant insertion tool, such as an implant impactor or a screwdriver, along the current axis.

[0031] In some embodiments, the end effector may be connected to the actuation unit by a planar mechanism configured to constrain movement of the cutting tool within the cutting plane.

[0032] Advantageously, the cutting tool can be decoupled from the planar mechanism. Preferably, the attachment means of the cutting tool provide a reproducible fixation, especially if the cutting tool is not intended to accommodate a tracker.

[0033] There are several different architectures for implementing the planar mechanism. For example, the planar mechanism can be made with only one rotation axis and one translation axis that carries the cutting tool along its length. Alternatively, the planar mechanism can be made from two orthogonal translation and rotation axes. According to another embodiment, the planar mechanism can be an arch-shaped slider that includes a rotation axis and a translation axis that carries the cutting tool.

[0034] According to the embodiment, the planar mechanism is passive, meaning that the mechanism is not motorized and can be freely operated by the user. One advantage of such a passive mechanism is that the user does not lose all of his senses when manipulating the saw in the bone. For example, the surgeon is free to operate the saw in the cutting block and is used to detect when the saw blade reaches the back of the bone by sensing the change in the resistance of the bone, and this sense is fully preserved by the passive planar mechanism, which has very low friction at its joints.

[0035] Alternatively, the planar mechanism may also be at least partially active, i.e., it comprises at least one motorized degree of freedom. If the planar mechanism is active, i.e., it comprises at least two motorized degrees of freedom, the cutting may be performed automatically. It should be noted that all said motorized degrees of freedom are configured to move the cutting tool in the cutting plane.

[0036] Regardless of the embodiment, the planar mechanism may include a locking system that locks each of its degrees of freedom once the cutting plane is aligned with the target plane.

[0037] The actuation unit can have a serial architecture made of multiple moving segments. In some embodiments, the actuation unit has three motorized rotational degrees of freedom for adjusting the position and orientation of the cutting plane relative to each target plane. In other embodiments, the actuation unit has two motorized rotational degrees of freedom and one or two motorized translational degrees of freedom. Generally speaking, the actuation unit includes three to five motorized degrees of freedom, at least two of which are orthogonal to each other in rotational degrees of freedom. The segments and their components are optimally integrated to make the robotic device as compact and lightweight as possible while remaining strong enough to hold the planar mechanism and surgical tools and resist some of the normal pressure applied by the user when the user manipulates the surgical tools.

[0038] In some embodiments, the architecture of the actuation unit is fabricated with three rotational degrees of freedom.

[0039] In some embodiments, the segments are arranged such that the first and third axes of rotation are substantially parallel to one another and the second axis is substantially orthogonal to the first and third axes.

[0040] In other embodiments, either the first and second axes or the second and third axes are substantially parallel to one another, and the first axis is substantially perpendicular to the third axis.

[0041] When used for knee arthroplasty (TKA, UKA, etc.), the robotic device can be positioned on the medial (inner) or lateral (outer) side of the target leg. The first axis of rotation is intended to be substantially perpendicular to the sagittal plane of the knee. For either application of the robotic system, some anatomical landmarks can be defined that are easy to identify and use to generally align the actuation unit.

[0042] In some embodiments, the architecture of the actuation unit may allow for further movements within the cutting plane, which may or may not be motorized.

[0043] As will be explained in more detail below, the actuation units are controlled by a control unit, which may be integrated within the robotic device or may be separate from the robotic device.

[0044] The system may comprise an articulated lockable holding arm supporting a base of the robotic device, said lockable holding arm being suitable for connection to a mechanical support such as an operating table, a leg holder, or for mounting to a mobile cart whose wheels can be blocked. The leg holder is an adjustable mechanism configured to maintain the legs in a predetermined flexed position when the patient is lying on the operating table.

[0045] The holding arm may consist of several articulated segments using ball joints, rotary joints, and / or translational joints.

[0046] The holding arm can be actively locked manually by a knob (mechanical locking system) or by a dedicated actuator of the locking system. The locking system can be an electric system, a piezoelectric system, a hydraulic system, a pneumatic system, or a combination of such systems (e.g., a hydraulic cylinder driven by an electric motor). For example, SMITH&NEPHEW sells an actively lockable passive holding arm under the name SPIDER™. The actuator can be a button, a foot switch, a remote button, etc. To operate the robotic device, the user must keep activating the actuator until the desired pose of the robotic device is achieved.

[0047] The holding arm supports the weight of the robotic device and maintains its gross positioning relative to the anatomical structure to be treated, thus limiting the user's movements when manipulating the device and, in advantageous embodiments, damping reaction forces caused by user and / or patient movements, cutting tool vibrations, and movement of the actuation unit.

[0048] According to an embodiment, the retaining arm is passive.

[0049] Advantageously, the holding arm may be progressively braked depending on the distance between the robotic device and its target position relative to the tracker fixed to the patient. For example, the braking force may be inversely proportional to the distance to the target position of the robotic device. Alternatively, one or more concentric volumes (e.g., cubes or spheres) may be defined around the target position of the robotic device. The braking force may be adjusted depending on the presence of the robotic device in one of said volumes. Thus, when the robotic device is close to the target position, the holding arm is braked and the user may receive force feedback information. Alternatively, the feedback information may be provided in the form of an optical or acoustic signal. For example, a variable flash frequency and / or intensity of the optical signal may indicate the distance between the robotic device and the target position. Similarly, a variable frequency, repetition rate, and / or amplitude of the acoustic signal may indicate said distance. In either case, the braking is never complete, so that the user can always manipulate the robotic device to the final desired position. The holding arm is then locked depending on an action from the user (e.g., the operation of an actuator, e.g., the release or pressing of a button). If it is desired to move the robotic device again, the user must again operate the actuator to release the holding arm, possibly with the above-mentioned braking force. When a new target position for the robotic device is defined, a new amount of braking is defined and the braking is adjusted based on the new amount.

[0050] Preferably, the connection between the holding arm and the actuation unit is as close as possible to the first segment of the actuation unit or to the center of gravity of the robotic device in order to minimize the effect of the lever arm. The part of the actuation unit attached to the holding arm is called the base of the robotic device.

[0051] According to an embodiment, the base of the robotic device may be fixed to the holding arm. This architecture is advantageous in that it minimizes the weight of the moving components of the actuation unit. As a result, the robotic device can be more responsive, which is favorable for real-time control of the cutting plane or axis.

[0052] The system further includes a tracking unit configured to determine in real time the orientation of the saw relative to the anatomical structure to be cut.

[0053] The tracking unit may typically be equipped with a tracking system, which is known per se.

[0054] Tracking systems commonly used in computer-assisted surgery use different technologies that can be used individually or in combination: passive optics, active optics, electromagnetic, gyroscopic inertial measurement, ultrasound, etc. According to a preferred embodiment, the tracking system is based on passive optical technology.

[0055] The tracking unit comprises at least one tracker, which may be attached to any component of the actuation unit, for example one of the movable segments.

[0056] The position of each segment of the actuation unit is known in real time due to the encoders or sensors of the servo motors and a calibrated model of the robotic device that includes all axes and distances of the segments of the actuation unit. Using this model and well-known geometric modeling techniques in robotics, it is possible to calculate the relative positions of all segments, so that if one measurement is known in a coordinate system that is attached to the base of the robotic device using an external tracker, any segment position is known in the same coordinate system. Furthermore, if a tracker is attached to the base of the actuation unit and a second tracker is attached to the anatomical structure, the pose of any segment of the actuation unit is known in the coordinate system attached to the tracker of the anatomical structure.

[0057] The control unit is coupled to the tracking unit and is configured to control the actuation unit to align a current plane or axis of the end effector with a respective one of a plurality of target planes and / or axes to treat an anatomical structure.

[0058] A general overview of the surgical system is shown in Figure 3. In the illustrated embodiment of the robotic device, the end effector 2 comprises a bar. However, other components of the system may be used with the other end effectors described above.

[0059] The robotic device 1 comprises a base 10, a motorized actuation unit 11, and a surgical bar end effector 2. The bar is connected to the actuation unit by a planar mechanism 12, with a first end attached to a terminal segment of the actuation unit and a second end rigidly attached to the bar 2.

[0060] In particular, when the burr head is small (e.g., having a diameter of about 3 mm), manipulation of the burr constrained in the cutting plane allows for planar cuts to be performed. The tip of the burr can be spherical or cylindrical. Typically, the tip of a 3 mm diameter cylindrical burr constrained by a planar mechanism to remain in a plane parallel to the cylindrical axis is rigid enough to make large cuts and small enough to perform high speed cuts.

[0061] The base 10 may be attached to a lockable retaining arm (not illustrated in FIG. 3).

[0062] The tracker 30 is attached to the bone B to be cut.

[0063] A tracker 31 is attached to the end effector 2 and another tracker 32 is attached to the base 10 of the robotic device to determine in real time the relative positions of the end effector and the bone being cut.

[0064] In the illustrated embodiment, the trackers 30, 31, 32 are optical trackers and are tracked by a local camera 3. In other embodiments, the trackers may be electromagnetic trackers, tracked by an electromagnetic tracking unit.

[0065] A control unit (not shown) controls the actuation units to keep the current axis of the bur along the target axis to compensate in real time for small movements from the patient or surgeon.

[0066] Since the model of the robotic device and the positions of the servo motors of the actuation unit are known, the tracker 32 attached to the base 10 may be sufficient to control the robotic device, but the tracker 31 attached to the end effector provides additional information regarding the position and orientation of the bar.

[0067] 4 shows another embodiment of the present robotic device, in this case where the end effector comprises a saw. Elements denoted by the same references as those in FIG. 3 perform the same functions and therefore need not be described again.

[0068] The robotic device 1 comprises a base 10, a motorized actuation unit 11 and an end effector 2 which is a surgical saw. The saw is connected to the actuation unit 11 by a planar mechanism 12.

[0069] Base 10 is securely attached to the end of a lockable holding arm 13. The opposite end of arm 13, not visible in Figure 4, can be securely attached to the operating table or to a cart that is placed in the vicinity of the operating table.

[0070] A tracker (e.g., an optical or electromagnetic tracker), not illustrated, is attached to the patient's anatomy and to the robotic device (e.g., attached to the base and, advantageously, also to the end effector).

[0071] FIG. 5 is a flow chart illustrating an embodiment of a method performed by the control unit.

[0072] Prior to carrying out the method, a number of target planes or axes may be planned by the user. This planning step may be performed by techniques known per se and is not described herein. Typically, the user determines the sequence of cuts to be made as well as the respective positions and orientations of the target planes or axes with respect to the anatomical structure. Thus, the plan may include a sequence of at least two cuts according to different target planes or axes, which are made in a predefined sequence. The plan may be generated by the control unit itself or may be generated by another device and transferred to the control unit.

[0073] For safety reasons, the end effector cannot be moved to a different position when the cut is being made.

[0074] Thus, in a first step (step 100), the control unit must determine that the robotic device is waiting to receive instructions to align the end effector with a target surface or axis (standby mode).

[0075] This determination can be made by a variety of techniques, possibly combined.

[0076] For example, if the end effector is a powered tool (e.g., a surgical saw, drill or burr), the tool being in the off state can be an indicator that the previous cutting step has been accomplished and that the end effector must be aligned with the next target plane or axis. In fact, the end effector cannot move while the procedure is being performed (working mode).

[0077] However, this off state may not be sufficient alone and may be supplemented by other information, such as a calculation of the completeness of the cut by an algorithm executed by the control unit, which may be based, for example, on the geometry of the bone and the path or position of the end effector.

[0078] Another possibility is to use medical images and / or anatomical landmarks to determine the position of the end effector relative to the anatomical structure. Indeed, once a cut is finished, the user or the robotic device may retract the end effector from the bone and wait for the next cut to be made. Thus, a given distance between the end effector and the anatomical structure can be an indication of the waiting state of the robotic device.

[0079] Thanks to the anatomical structure and the localization data of the end effector provided by the tracker, the control unit can calculate the distance between the surface of the anatomical structure and the end effector.

[0080] If medical images of the anatomical structure are available, it may also be possible to determine the distance between the surface of the anatomical structure and the end effector from processing the images. The medical images may be pre-operative 3D images (e.g., CT scans or MRI images) used to navigate the end effector. Alternatively, the medical images may be 2D or 3D intra-operative images.

[0081] In an image-free system, it may also be possible to determine the distance between the surface of the anatomical structure and the end effector by intraoperatively acquiring anatomical landmarks by a pointer tracker with a tracking unit.

[0082] In a second step (step 200), the control unit must detect at least one external force applied in a first direction to the end effector or actuation unit. This force may also be applied to the planar mechanism, if present. More generally, the force may be applied to any part of the robotic device that is not rigidly connected to the holding arm.

[0083] Such an external force may be applied to the end effector by a user to indicate that a position change is desired.

[0084] The external force (also referred to herein as the "trigger force") may be in the form of a linear force and / or a torque.

[0085] For safety reasons, it may be preferred that the trigger force combines at least one linear force and at least one torque, or at least two linear forces, or at least two torques along different or the same direction within a given time frame. Otherwise, the trigger force may combine at least two forces or torques according to a predefined sequence. The sequence may preferably be defined by predefined spatial parameters (e.g. one or more directions) and time parameters (e.g. duration of application of a force or torque and / or duration during application of successive forces or torques), which together constitute a predefined signal interpreted by the control unit as a sequence for moving the end effector to a new position. In this way, the risk of triggering an undesired position change can be minimized.

[0086] Preferably, the sequence can be designed to make it less likely to occur unintentionally. For example, the sequence can include at least one positive torque and one negative torque applied sequentially in a first direction of the end effector. Alternatively, the sequence can include at least one torque applied about a first axis and one force applied along a second axis perpendicular to the first axis. In yet another example, a force can be applied to the actuation unit and the end effector can be rocked back and forth with a large amplitude due to the planar mechanism.

[0087] Detection of the trigger force may be done by several techniques, which may be combined, and which generally involve components already present in the system.

[0088] In some embodiments, the detection of the trigger force may be performed by sensing a current value in at least one servo motor that is greater than a first threshold value. Indeed, the application of an external force to the actuation unit or the end effector generates a force or torque by at least one servo motor that operates under the applied force and maintains the end effector in a current standby position. The force or torque applied by the servo motor results in an increase in the current consumption in the servo motor. Said current may be measured (in amperes) by sensors in the servo motor, in the control unit and / or in the power supply unit to the servo motor.

[0089] Depending on the direction of the external force applied to the actuation unit or the end effector, the current may increase in one or more motors of the actuation unit. A specific threshold value may be defined for each of the servo motors involved.

[0090] Advantageously, the directions in which trigger forces are expected can be monitored more precisely, for example by requiring smaller thresholds for servo motors capable of exerting opposing forces or torques in these directions.

[0091] In some embodiments, detection of the trigger force may be performed by sensing a displacement of the end effector greater than a second threshold.

[0092] The displacement can be sensed based on tracking data using a tracker attached to the end effector.

[0093] Advantageously, directions in which trigger forces are expected can be monitored more precisely, for example by requiring smaller displacement thresholds in these directions.

[0094] The detection can also include detecting the duration of the application of the trigger force, as well as the direction of the force applied by the user, and detecting the trigger force only if the duration exceeds a third threshold, intended to avoid movement of the end effector to a new position that would be triggered by an impact or unintended pressure on the end effector or actuation unit.

[0095] For this purpose, the control unit may include a timer triggered by the detection of a first event, potentially representing an expected signal. For example, an external pressure may need to be long enough to trigger a movement of the robotic device. In that case, the control unit may trigger the timer as soon as the current of a given servo motor exceeds a first threshold, and detect that the applied force belongs to the signal if the current is still greater than the first threshold for a duration greater than a third threshold. In some embodiments, the trigger force may be a sequence of different individual forces applied in the same direction or in different directions. In that case, the control unit may determine the duration of each individual force and check whether each duration is within a given range.

[0096] If the detected trigger force is a combination of individual forces or torques, the time period between application of successive individual forces or torques may also be measured and compared to a predefined range, such that the control unit can detect the trigger force only if the time period between successive application of the individual forces or torques is within said predefined range.

[0097] As mentioned above, the above detection techniques may be combined. For example, a user may first rock the end effector according to a predefined pattern (e.g. left / right or right / left) for a planar mechanism. This movement puts the control unit into an alert state. The control unit may trigger a timer to measure the period between such a first and a subsequent event in the form of an applied trigger force. Thus, the user may apply said force in a predefined direction of the end effector or actuation unit, which is detected by the control unit.

[0098] In some embodiments, the control unit and the robotic device may be configured to provide a "push button" sensation to the user. In that case, by applying a trigger force in a first direction, the control unit may trigger a displacement of the end effector in the first direction by a predefined amplitude, which results in an offset of the end effector relative to its initial position. For example, if a linear force is applied by the user, the end effector may typically translate by 1-10 mm. If a torque is applied by the user, the end effector may rotate by 0.5-5°. The offset of the end effector may be cancelled upon release of the trigger force.

[0099] The "push button" action may be short enough that either the displacement of the end effector begins only once the trigger force is released by the user, or the displacement begins when the trigger force is applied, and then the trigger force can be released any time after the movement begins. The action may also be long enough that the displacement of the end effector begins, and lasts as long as the user applies the trigger force. In the latter case, during the displacement, the instantaneous position of the end effector is compared, at the time of the offset, to the position the end effector would have if this "push button" action was not used. Once the trigger force is released, the offset is cancelled.

[0100] The force applied to the end effector and / or actuation unit may not be the only parameter considered in the detection step. For example, if the end effector is a powered tool, detection of the trigger force may be combined with detection of the user pressing the trigger of the tool. If the robotic device is in an idle state, pressing the trigger may not activate the tool, but may generate an electrical signal detectable by the control unit. Thus, the combination of a trigger force in a given direction of the end effector and / or actuation unit and detection of an electrical signal at the trigger of the powered tool can be interpreted as the required signal.

[0101] As a result of the first and second detection steps, the control unit triggers a position change of the end effector by the actuation unit to align the current plane or axis with the next target plane or axis (step 300).

[0102] In some embodiments, the next target plane or axis may be spatially closest to the current plane or axis, meaning that this plane or axis requires the smallest displacement from the current position of the end effector, which may be considered in the direction of applying the trigger force.

[0103] In other embodiments, the next target plane or axis may be the next or previous plane or axis according to the planned surgical workflow. For example, if a cut has to be made again or improved, it may be necessary to go back to the previous target plane or axis. Advantageously, the direction with respect to the planned workflow (i.e. the next or previous target plane or axis) can be indicated by the opposite direction of the trigger force. For example, an upwardly applied force can trigger a transition to the next step in the planned workflow, and a downwardly applied force can trigger a transition to the previous step in the planned workflow.

[0104] In some embodiments, an external force (or a sequence of forces and / or torques) different from the trigger force can be used to stop movement of the end effector, for example to cancel a signal previously detected by the control unit.

[0105] Advantageously, the control unit is configured to record the status of a given cutting step, otherwise it may be possible for the control unit to determine whether a cut according to a given plane or axis has already been made or not.

[0106] For example, at the end of the anterior cut made, the user may want to return to the distal cut to check the plane with the saw blade. In this case, if the robot is again at the distal plane when this cut has already been made, the robotic device will remain in standby mode. If the user does want to check the cut made with the saw blade, the user applies a trigger force directly and the robotic device can then move to the next cut without making the cut again.

[0107] The description so far has focused on robotic devices with less than six degrees of freedom, which distinguish them from larger surgical robots by their smaller inertia, especially along the first axis, and therefore by their higher responsiveness, which is especially necessary to compensate for bone movements in real time, and the present disclosure is also applicable to surgical robots with six degrees of freedom. Indeed, these robots also integrate servo motors or other means, which make it possible to detect the application of trigger forces to the robot, or to the end effector and a control unit that may be configured to trigger a position change of the end effector in response to such a trigger force. References International Publication No. 2018 / 103945

[0108] [Embodiment] (1) A surgical system for treating an anatomical structure according to a plurality of target planes and / or axes, comprising: A robotic device (1), An end effector (2) that defines a current plane or axis; an actuation unit (11) connected to the end effector (2); The robot device (1), a tracking unit (3) configured to determine the current plane or axis pose; a control unit coupled to the tracking unit, the control unit being configured to control the actuation unit to align the current plane or axis of the end effector with a respective one of the plurality of target planes and / or axes to treat the anatomical structure; Equipped with The robotic device has at least the following modes: a working mode, in which a procedure is being performed with the end effector constrained to one target plane or axis by the actuation unit; and a standby mode, in which no treatment is being performed and the actuation unit is operable to move the end effector in alignment with another target plane or axis; It can operate with The control unit: (a) determining that the robotic device (1) is in the standby mode; (b) detecting a trigger force applied to the end effector (2) and / or the actuation unit (11) in at least one first direction; (c) as a result of determining (a) and detecting (b), triggering a change in position of the end effector (2) by the actuation unit (11) so as to align the current plane or axis with a next target plane or axis; It is further composed of The surgical system. (2) A surgical system as described in embodiment 1, wherein the end effector (2) comprises at least one of a cutting tool such as a saw, a burr or drill, a cutting guide, and a guiding tool. (3) A surgical system as described in embodiment 1 or 2, wherein the tracking unit (3) comprises a tracker (31, 32) securely attached to the end effector (2) and / or the actuation unit (11). (4) A method for triggering position changes of a robotic device (1) for treating an anatomical structure according to multiple target planes and / or axes, the robotic device comprising an end effector (2) defining a current plane or axis and an actuation unit (11) coupled to the end effector (2), the robotic system being operable in at least the following modes: a working mode, in which a procedure is being performed with the end effector constrained to one target plane or axis by the actuation unit; and a standby mode, in which no treatment is being performed and the actuation unit is operable to move the end effector in alignment with another target plane or axis; It can operate with (a) determining that the robotic device (1) is in the standby mode; (b) detecting a trigger force applied to the end effector (2) and / or the actuation unit (11) in at least one first direction; (c) triggering a change in position of the end effector (2) by the actuation unit (11) as a result of the determination and detection made in steps (a) and (b) in order to align the end effector (2) with a next target plane or axis; The method comprising: (5) The method of claim 4, wherein the trigger force comprises at least one of a linear force and a torque.

[0109] (6) The method of claim 4 or claim 5, wherein step (b) comprises sensing a current value in at least one servo motor of the actuation unit (11) that is greater than a first threshold value. (7) A method according to any one of embodiments 4 to 6, wherein step (b) includes sensing a displacement of the end effector (2) greater than a second threshold. (8) The method of claim 7, further comprising sensing the displacement of the end effector (2) based on tracking data of the tracking unit (3). (9) A method according to any one of claims 4 to 8, wherein step (b) includes detecting a series of external linear forces and / or torques applied to the end effector and / or the actuation unit. (10) A method according to any one of claims 4 to 9, wherein the end effector is equipped with a powered tool including a trigger, and step (b) further comprises the step of detecting pressure acting on the trigger while the tool is in an off state.

[0110] (11) A method according to any one of embodiments 5 to 10, wherein the position change of the end effector is performed substantially in accordance with the first direction. (12) A method according to any one of embodiments 4 to 11, further comprising the step of stopping the triggered movement of the robotic device as a result of the detection of an external force different from the trigger force. (13) The method of any of embodiments 4 to 12, wherein step (a) includes determining the position of the end effector (2) relative to the anatomical structure (B) using medical images and / or anatomical landmarks. (14) A method according to any one of embodiments 4 to 13, wherein step (b) further comprises the steps of sensing the duration for which the external force is applied, and comparing the sensed duration with a duration threshold. (15) A method according to any one of embodiments 4 to 14, wherein in step (c), the control unit triggers a displacement of the end effector (2) by the determined offset amplitude in the first direction, and the offset is cancelled when the trigger force is released.

Claims

1. 1. A surgical system for treating an anatomical structure according to a plurality of target planes and / or axes, comprising: A robotic device (1), An end effector (2) that defines a current plane or axis; an actuation unit (11) connected to the end effector (2); The robot device (1), a tracking unit (3) configured to determine the current plane or axis pose; a control unit coupled to the tracking unit, the control unit being configured to control the actuation unit to align the current plane or axis of the end effector with a respective one of the plurality of target planes and / or axes to treat the anatomical structure; Equipped with The robotic device has at least the following modes: a working mode, in which a procedure is being performed with the end effector constrained to a target plane or axis by the actuation unit; and a standby mode, in which no treatment is being performed and the actuation unit is operable to move the end effector in alignment with another target plane or axis; It can operate with The control unit: (a) determining that the robotic device (1) is in the standby mode; (b) sensing, by a sensor, a current value in at least one servo motor of said actuation unit (11) that is greater than a first threshold value; (c) as a result of the determining (a) and sensing (b), performing a position change of the end effector (2) by the actuation unit (11) so as to align the current plane or axis with a next target plane or axis; It is further composed of The surgical system.

2. 1. A surgical system for treating an anatomical structure according to a plurality of target planes and / or axes, comprising: A robotic device (1), An end effector (2) that defines a current plane or axis; an actuation unit (11) connected to the end effector (2); The robot device (1), a tracking unit (3) configured to determine the current plane or axis pose; a control unit coupled to the tracking unit, the control unit being configured to control the actuation unit to align the current plane or axis of the end effector with a respective one of the plurality of target planes and / or axes to treat the anatomical structure; Equipped with The robotic device has at least the following modes: a working mode, in which a procedure is being performed with the end effector constrained to a target plane or axis by the actuation unit; and a standby mode, in which no treatment is being performed and the actuation unit is operable to move the end effector in alignment with another target plane or axis; It can operate with The control unit: (a) determining that the robotic device (1) is in the standby mode; (b) sensing, by a tracker attached to the end effector, a displacement of the end effector that is greater than a second threshold; (c) as a result of the determining (a) and sensing (b), performing a position change of the end effector (2) by the actuation unit (11) so as to align the current plane or axis with a next target plane or axis; It is further composed of The surgical system.

3. 1. A surgical system for treating an anatomical structure according to a plurality of target planes and / or axes, comprising: A robotic device (1), An end effector (2) that defines a current plane or axis; an actuation unit (11) connected to the end effector (2); The robot device (1), a tracking unit (3) configured to determine the current plane or axis pose; a control unit coupled to the tracking unit, the control unit being configured to control the actuation unit to align the current plane or axis of the end effector with a respective one of the plurality of target planes and / or axes to treat the anatomical structure; Equipped with The robotic device has at least the following modes: a working mode, in which a procedure is being performed with the end effector constrained to a target plane or axis by the actuation unit; and a standby mode, in which no treatment is being performed and the actuation unit is operable to move the end effector in alignment with another target plane or axis; It can operate with The control unit: (a) determining that the robotic device (1) is in the standby mode; (b) detecting an external linear force and / or torque applied to the end effector and / or the actuation unit; (c) as a result of the determination (a) and detection (b), performing a position change of the end effector (2) by the actuation unit (11) so as to align the current plane or axis with a next target plane or axis. It is further composed of The surgical system.

4. The surgical system of any one of claims 1 to 3, wherein the end effector (2) comprises at least one of a cutting tool such as a saw, a burr or drill, a cutting guide, and a guiding tool.

5. A method for operating a control unit for performing position changes of an end effector (2) of a robotic device (1) for treating an anatomical structure according to a number of target planes and / or axes, said robotic device comprising the end effector (2) defining a current plane or axis and an actuation unit (11) coupled to said end effector (2), said robotic device being operable in at least the following modes: a working mode, in which a procedure is being performed with the end effector constrained to a target plane or axis by the actuation unit; and a standby mode, in which no treatment is being performed and the actuation unit is operable to move the end effector in alignment with another target plane or axis; It can operate with The control unit: (a) determining that the robotic device (1) is in the standby mode; (b) sensing, by a sensor, a current value in at least one servo motor of said actuation unit (11) that is greater than a first threshold value; (c) as a result of the determination and the sensing performed in steps (a) and (b), sending a signal to the actuation unit (11) to effect a position change of the end effector (2) by said actuation unit (11) in order to align the end effector (2) with a next target plane or axis; A method of operating the control unit, comprising:

6. A method for operating a control unit for performing position changes of an end effector (2) of a robotic device (1) for treating an anatomical structure according to a number of target planes and / or axes, said robotic device comprising the end effector (2) defining a current plane or axis and an actuation unit (11) coupled to said end effector (2), said robotic device being operable in at least the following modes: a working mode, in which a procedure is being performed with the end effector constrained to a target plane or axis by the actuation unit; and a standby mode, in which no treatment is being performed and the actuation unit is operable to move the end effector in alignment with another target plane or axis; It can operate with The control unit: (a) determining that the robotic device (1) is in the standby mode; (b) sensing, by a tracker attached to the end effector, a displacement of the end effector that is greater than a second threshold; (c) as a result of the determination and the sensing performed in steps (a) and (b), sending a signal to the actuation unit (11) to effect a position change of the end effector (2) by said actuation unit (11) in order to align the end effector (2) with a next target plane or axis; A method of operating the control unit, comprising:

7. A method for operating a control unit for performing position changes of an end effector (2) of a robotic device (1) for treating an anatomical structure according to a number of target planes and / or axes, said robotic device comprising the end effector (2) defining a current plane or axis and an actuation unit (11) coupled to said end effector (2), said robotic device being operable in at least the following modes: a working mode, in which a procedure is being performed with the end effector constrained to a target plane or axis by the actuation unit; and a standby mode, in which no treatment is being performed and the actuation unit is operable to move the end effector in alignment with another target plane or axis; It can operate with The control unit: (a) determining that the robotic device (1) is in the standby mode; (b) detecting an external linear force and / or torque applied to the end effector and / or the actuation unit; (c) as a result of the determination and detection made in steps (a) and (b), sending a signal to the actuation unit (11) to effect a position change of the end effector (2) by said actuation unit (11) in order to align the end effector (2) with a next target plane or axis; A method of operating a control unit.

8. 8. A method of operating a control unit according to any one of claims 5 to 7, wherein step (a) comprises determining a position of the end effector (2) relative to the anatomical structure (B) using medical images and / or anatomical landmarks.

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