Laser surgical system for cutting hard tissue

Abstract

The present invention relates to a laser surgical system for cutting hard tissue on an object, comprising a handheld laser applicator, a collaborative robot with a robot arm to which the handheld laser applicator is attached, a navigation system with which the instantaneous position of the laser applicator relative to the object can be detected, and a controller for the collaborative robot. The laser applicator has a measuring device with which the cutting depth of a kerf produced by a processing laser beam and the residual thickness of the hard tissue in the kerf can be measured.The control system directs the collaborative robot during the execution of a cut based on data from the navigation system and the measuring device in such a way that it maintains a cutting distance of the laser applicator to the object required for cutting via the robot arm and only allows a feed movement of the laser applicator along a cutting line by the operator when a cut that has just been carried out is completely finished.

Description

Technical application area

[0001] The present invention relates to a laser surgical system for cutting hard tissue on an object, in particular a patient's bone, with a handheld laser applicator.

[0002] The invention addresses the problem of hard tissue surgery for the removal of healthy or diseased bone tissue. Typical applications include spinal surgery for the surgical treatment of spinal stenosis, which is bony growth that extends inward into the spinal canal and compresses the spinal cord. In advanced stages, this leads to pain and paralysis. Conventional surgical therapy involves mechanically opening the vertebral body with a ball-head burr and then removing the hard tissue growing into the spinal canal with a bone punch. The burr is opened under high pressure. Therefore, in 1.5% of cases, the surgeon may accidentally protrude the burr into the spinal canal at the point of penetration, injuring the spinal cord or nerve root.The consequences for the affected patients are paraplegia and bladder and bowel incontinence.

[0003] Another application is the opening of the skull, known as craniotomy. Here are some examples: In brain tumor surgery, a large section of bone is removed from the skull using a special burr called a trephine to create access to the tumor. During this procedure, the dura mater, the tough outer membrane covering the skull, can be torn uncontrollably. Consequently, the craniotomy often needs to be extended to repair the torn dura at the end of the operation. Tearing the dura can also lead to infections and thus impaired wound healing. Another application of craniotomy is drilling a hole approximately 10 mm in diameter to insert electrodes for deep brain stimulation. These electrodes are positioned with high precision in the brain in areas that induce tremors, or shaking paralysis of the extremities.The electrodes are connected to a pacemaker that generates an inhibitory electrical signal, suppressing the electrical nerve impulses (action potentials) that cause the tremor. The hole is drilled while the patient is awake under local anesthesia, which is not painful for the patient but is extremely stressful psychologically due to the noise and vibrations.

[0004] Further applications are found in tumor surgery for the removal of bone tumors. Malignant bone tumors have a poor survival prognosis because they frequently metastasize. In surgical therapy, they are therefore removed with a large margin of the tumor edges visible in preoperative imaging to ensure that the tumor is completely removed from the bone structure. The high degree of radicality in tumor removal is also due to the fact that, unlike the resection of tumors in soft tissue, frozen sections cannot be taken from the tumor margins in hard tissue. These frozen sections allow the pathologist to examine the edges of the removed tumors during the operation to see whether they have been completely removed or whether the resection margin still extends into healthy tissue. Because of the lack of rapid diagnostics during surgery in bone surgery, often more healthy tissue is removed than absolutely necessary.For example, soft tissue tumors of the oral cavity can infiltrate the jawbone and then spread within the bone. If the tumor is only attached to the jawbone, oncological guidelines stipulate that the jaw is removed at the point of attachment. However, approximately half of these removed jawbones were classified postoperatively by pathologists as not infiltrated with tumor tissue. State of the art

[0005] The conventional approach in hard tissue surgery and its disadvantages have already been described above for various applications.

[0006] From EP 2480153 B1, a computer-assisted and robot-controlled laser surgical system for laser osteotomy is also known, in which hard tissue is cut fully automatically or via a joystick using a photoablation laser source mounted in a robot arm. From EP 3558150 A1, it is known to measure the cutting depth during such a cut using optical coherence tomography (OCT).

[0007] The object of the present invention is to provide a laser surgical system with which bone tissue can be efficiently and precisely removed by a surgeon without injuring structures lying beneath the bone. Description of the invention

[0008] The problem is solved with the laser surgical system according to claim 1. Advantageous embodiments of the laser surgical system are the subject of the dependent claims or can be found in the following description and the exemplary embodiments.

[0009] The proposed laser surgical system for cutting hard tissue on an object, in particular a patient's bone, comprises a handheld laser applicator that can be guided by hand by the surgeon during cutting, a collaborative robot (cobot) with a robotic arm to which the handheld laser applicator is attached, a navigation system that can detect the instantaneous position of the laser applicator relative to the object during cutting, and a control system that controls the collaborative robot during the execution of the cut with the laser applicator.In the proposed system, the laser applicator comprises at least one dynamic 2D beam deflection device, through which a processing laser beam from a laser beam source, preferably a short-pulse MIR laser, can be guided across a region of the hard tissue for cutting. The applicator also includes, or is connected to, a measuring device for measuring the cutting depth of the kerf created in the hard tissue by the processing laser beam and the residual thickness of the hard tissue within the kerf. Various measurement techniques can be used for measuring the cutting depth and residual thickness, in particular optical or acoustic measurement techniques. For example, optical measurements with a triangulation sensor or confocal sensor, acoustic measurements with a transducer (microphone), ultrasonic measurements, or laser ultrasonic measurements can be performed.Preferably, an OCT measuring device (OCT = Optical Coherence Tomography) is used, which directs a measuring beam coaxially to the processing laser beam onto the hard tissue to measure the cutting depth and the remaining thickness of the hard tissue. The processing laser beam and the measuring beam are preferably coupled into the laser applicator via a flexible or articulated beam guidance device connected to the laser applicator, through which the measuring device can also be coupled to the laser applicator.

[0010] The control system directs the collaborative robot based on data from the navigation system and the measuring device. In the proposed laser surgical system, it is designed to control the collaborative robot in such a way that the robot arm maintains the necessary cutting distance between the laser applicator and the object for cutting the hard tissue. The system only allows the surgeon to advance the laser applicator along the cutting line once a previously executed cut is complete, i.e., when a predetermined residual thickness of the hard tissue is reached at that point, or when the hard tissue has been completely cut through, resulting in a residual thickness of 0 mm. The cutting distance must generally be selected so that the focus of the processing laser beam is always on the surface of the material being cut.

[0011] In a preferred embodiment, the collaborative robot is controlled during the execution of the cut with the laser applicator, based on data from the navigation system and data about a predefined path of the cutting line, in such a way that it allows the operator to move the laser applicator only within a predefined area or corridor along the cutting line. This prevents excessive deviations from the planned cutting line.

[0012] The laser surgical system and the cutting process utilize focused, pulsed laser radiation in a wavelength range suitable for cutting hard tissue, preferably short-pulse laser radiation in the MIR range, which is strongly absorbed by bone tissue. The radiation is manually focused by the surgeon onto the bone surface to be cut using the laser applicator. Within the applicator, the cutting / processing laser beam and the OCT measurement beam are preferably superimposed and guided coaxially. The measuring device measures the cutting depth synchronously with the cutting process and, once a small remaining thickness of bone or hard tissue of a few hundred micrometers is reached, the residual thickness of the bone or hard tissue. Preferably, a high-repetition OCT system, e.g., with an 80 kHz measurement frequency, is coordinated with the processing laser for this measurement so that a measurement is always taken during the pulse pauses, e.g.,Approximately 20 µs after the processing laser pulse, the inline residual thickness measurement is performed as soon as the generated process glow has subsided and no longer interferes with the OCT measurement. This inline measurement allows the cutting process to be controlled, ensuring that structures behind or beneath the bone are not damaged. Depending on the application, a thin, defined bone lamella (opening of the vertebral body or skull) is left at the base of the cut, and the removed bone is mechanically removed with minimal force. Alternatively, the bone can be completely severed if there are no critical structures behind it.

[0013] The procedure is performed manually by the surgeon, with the collaborative robot assisting in the hand-held laser applicator. The handheld laser applicator is located at the end of the collaborative robot arm. The surgeon can guide the laser applicator along the cutting line like a high-precision jigsaw. The collaborative robot ensures that the laser applicator maintains the correct distance from the bone surface for an efficient cutting process. Furthermore, the collaborative robot provides the surgeon with haptic feedback via the laser applicator. To achieve this, the collaborative robot's motors at the joints of the robot arm generate a counterforce to the surgeon's forward movement, pushing the laser applicator in a specific direction so that it remains in a defined position. Simultaneously, the applicator performs a microscopic cut of defined width and length locally using the integrated 2D mirror scanner.Only when this cut reaches the predetermined, defined residual thickness is the feed of the laser applicator by the length of the generated microscopic cut line released by the collaborative robot. With efficient and rapid laser ablation, this results in a quasi-continuous cutting process. Together with the inline measurement technology and the higher-level control system, the collaborative robot forms a robotic assistance system that supports the operator during the cutting process.

[0014] Furthermore, in a specific configuration for tumor surgery applications, the proposed system can also detect tumor cells intraoperatively. This aims to ensure that the tumor is demonstrably and completely removed from the bone while preserving as much healthy tissue as possible. In this configuration, the laser applicator is equipped with or connected to a spectroscopic measuring device that enables intraoperative detection of tumor cells. This can be achieved, for example, through autofluorescence measurement, fluorescence measurement using a specific fluorescent marker that labels the tumor cells, or Raman spectroscopy. Preferably, the spectroscopic measuring device uses the LIBS method (Laser-Induced Breakdown Spectroscopy). In this method, a plasma is locally ignited in the tissue within the spatial dimension of the laser focus using another short-pulse or ultrashort-pulse laser.The plasma generates characteristic, element-specific spectral lines that allow for the differentiation of healthy bone tissue from tumor tissue. An important factor is the high calcium content of healthy bone compared to that of tumor tissue. Furthermore, the concentrations of potassium and sodium are elevated in the tumor compared to healthy bone tissue. Additional spectral characteristics can also be determined using AI methods by training a self-learning system to distinguish between healthy bone and tumor tissue.

[0015] The proposed system preferably also includes a planning unit that uses preoperative image data to determine the tumor's location within the body / bone. Based on this data, the planning unit calculates a target trajectory for the incision line, along which the laser cutting process is to be guided. This target trajectory can then either be implemented directly by the system or serve as a suggestion for the surgeon, who can either accept it as suggested or define a modified target trajectory for the incision line via an interactive interface. The system monitors a corridor within which the surgeon is permitted to move the laser applicator and restricts the surgeon's movement, thus protecting healthy tissue away from the tumor and preventing the surgeon from cutting into the tumor tissue.In conjunction with the above configuration featuring a spectroscopic measuring device, the cutting line can also be adjusted during the cutting process. If the spectroscopic measuring device detects tumor tissue during the laser cutting process, the target curve for the cutting line is recalculated and dynamically adjusted via the robotic assistance system.

[0016] To ensure that preoperative planning data, the applicator position, and the patient's or object's position are correctly aligned, the proposed laser surgery system includes a navigation system. Such a navigation system, consisting of stereoscopic observation and fast, real-time image processing, is state of the art and commercially available.

[0017] After preoperative image data, intraoperative patient position, and the applicator position have been initially correlated, the navigation system can display the current position of the laser applicator or laser focus, as well as the resulting incision line and the inline-measured microscopic tumor distribution, within the preoperative image data by observing the applicator and patient. Furthermore, the navigation system allows it to react to patient movements, such as breathing, and to track the position of the applicator or laser focus in such a way that the incision is not affected by these movements.

[0018] The proposed laser surgical system, with its robotic assistance system, allows for greater surgical precision, efficiency, and operating room safety. Manual guidance of the laser cutting process enables the surgeon to maintain control over the surgical procedure and transfers responsibility for patient safety and the quality of the procedure to them. This lowers the hurdles for the system's approval compared to a fully automated surgical robot.

[0019] In contrast to the conventional approach using a saw or wire saw, free beam guidance allows for bone-sparing segment resection in long bones when the tumor has not penetrated the bone over its entire diameter.

[0020] Residual bone thickness measurement, preferably using OCT, enables a safe process for creating access within the bone while simultaneously protecting underlying, vulnerable structures. This avoids injury to such structures, for example, the labyrinth during brain surgery or the spinal cord in the vertebral canal, and dramatically increases surgical safety. Furthermore, when opening the skull or vertebral body, injury to the dura mater (the membrane covering the brain and spinal cord) and the associated infections / wound healing complications are avoided.

[0021] The system enables vibration-free and low-noise bone removal on the head using laser radiation during craniotomy (laser osteotomy). This significantly reduces the burden on patients during awake craniotomy and dramatically increases the acceptance and applications (brain tumor surgery) of awake craniotomy.

[0022] A preferred direct mechanical connection between the collaborative robot and the operating table reduces the risk of relative movement between the patient and the laser surgery system. This is particularly important in operations where the patient is firmly attached to the operating table, such as stereotactic brain surgery, as it ensures that the coordinates between the patient and the laser surgery system are fixed.

[0023] The proposed system allows for function- and structure-preserving surgery, for example, when removing bone tumors in the oral and maxillofacial region or near joints.

[0024] The advantageous design with the spectroscopic measuring device offers a benefit during the removal of bone tumors: Intraoperative diagnosis of bone metastases, achieved with this device and combined with a precise laser procedure, allows for the preservation of healthy bone tissue. This is particularly important for patients with bone replacement implants in the musculoskeletal system, as these implants typically require replacement approximately every 15 years, resulting in the loss of healthy bone. The removal of soft tissue tumors in the oral cavity, as described above, can also be performed in a more bone-sparing manner using this method.

[0025] Intraoperative tumor diagnostics with dynamic adjustment of the target trajectory via the assistance system also allows for the verification of tumor-free status through resection or the extension of the resection in the case of positive tumor diagnostics to achieve tumor-free status.

[0026] Preferred areas of application for the proposed laser surgical system have already been mentioned in the introductory description. Brief description of the drawings

[0027] The proposed laser surgical system is explained in more detail below using exemplary embodiments in conjunction with the drawings. These show: Fig. 1 a schematic representation of a first example of the laser applicator used in the proposed system; Fig. 2 a schematic representation of a further example of the laser applicator used in the proposed device; and Fig. 3 A schematic representation of an exemplary embodiment of the proposed laser surgical system in use. Ways to implement the invention

[0028] The proposed laser surgical system uses a specially designed laser applicator that is guided by hand by a surgeon during the procedure or incision. Fig. 1 and Fig. Figure 2 shows exemplary designs of this laser applicator in schematic representation, which replaces the drills and milling machines commonly used in hard tissue surgery with a laser and also saws in order to achieve a safe, noise- and vibration-free ablation process.

[0029] Pulsed laser radiation, preferably with pulse energies of 0.5 mJ to 10 J, is used for this purpose. This radiation can be used to cut narrow and deep fissures in bone tissue, for example, to create access to the brain. To ensure that the cutting process is efficient and does not cause thermal tissue damage, the laser pulses are distributed along the cutting line in such a way that, on the one hand, the resulting process heat does not accumulate locally, and on the other hand, a continuous, deep fissure is created. For this purpose, laser pulse repetition rates in the range of 1 Hz to 1000 kHz are preferably used. Suitable wavelengths are those that are well absorbed in bone tissue. Wavelengths between 1 µm and 11 µm are suitable, in particular those of the CO2 laser between 9.3 µm and 10.6 µm, as well as wavelengths between 2.8 and 3.2 µm. The process is controlled by a laser applicator (18), the function of which is described below. Fig. 1 is described.

[0030] The processing laser beam (2) from a laser beam source (1) is transmitted via a beam guide (3) and a telescope (4, 4') through beam splitters (5) and (5'). The small reflected portion of the laser radiation is detected by two position sensors (6, 6'). The position sensors determine the position and propagation direction of the processing laser beam (2) within the applicator. In case of misalignment, the beam position can be adjusted to the optical axis of the laser applicator using position measurement via two automatically adjustable mirrors (not shown) in the beam guide system. The processing laser beam (2) is guided to a dynamic 2D beam deflection unit (14) via a deflection element (13).Behind the beam deflection unit, the processing laser beam (2) is focused by a focusing optic (15) onto the surface of the bone (19) to be cut, exiting the housing of the applicator (18) through an exit aperture (16). Depending on the design, the exit aperture can be closed by the focusing optic (15) or by a protective window (16').

[0031] An OCT sensor (OCT = Optical Coherence Tomography) (7) emits an OCT measurement beam (8), which is guided to the applicator (18) via a beam guidance system (9), e.g., an optical fiber. This measurement beam (8) is guided through a telescope (10, 10') and behind the telescope via a deflecting element (11). The OCT measurement beam (8) is superimposed on the laser beam (2) at the beam splitter (5) and then continues coaxially with the laser beam (2). The two coaxial beams (12) pass through the beam splitter (5') and are guided via the deflecting element (13) to the dynamic beam deflection unit (14). The beam deflection unit (14) distributes the foci of the two coaxial beams (12) in the processing plane on the bone (19) in the feed direction (x-direction) of the cutting process and perpendicular to it (y-direction).During the ablation process, the bone surface is moistened with a water spray to ensure a carbonation-free and efficient laser ablation process. The spray comes from fine atomizing nozzles (17') arranged concentrically around the outlet opening (16) of the applicator housing or a handle (17) attached to it. Using the handle (17) on the applicator housing, the surgeon can guide the laser applicator (18) over the bone surface to be cut.

[0032] During the ablation process, the OCT sensor (7) measures the cutting depth with the OCT measuring beam (8). s and the remaining residual thickness d rThe measuring light travels antiparallel to the excitation direction of the OCT measuring beam (8) and is detected in the OCT sensor (7). The cutting process is controlled via the measuring signal so that a defined, thin residual thickness remains, preventing the processing laser beam (2) from damaging the tissue behind / beneath the bone (19). As the ablation depth increases, the position of the laser focus of the processing laser beam (2) is shifted into the bone (19) by adjusting a movable lens (4') of the telescope (4, 4'). Similarly, as the ablation depth increases, the focus of the OCT measuring beam (8) is shifted into the bone (19) by adjusting a movable lens (10') of the telescope (10, 10').

[0033] In a special version for intraoperative tumor diagnostics, the laser applicator (18) is equipped with an additional beam path for a second laser to excite plasma for generating a LIBS spectrum (LIBS = Laser-Induced Breakdown Spectroscopy), as well as with a beam path for guiding the emitted plasma light into a spectrometer for analyzing the emitted LIBS spectrum. A corresponding configuration is described in Fig. Figure 2 is shown as an example. Based on plasma luminescence, bone tumors and healthy bone tissue can be distinguished from one another via the intensity ratios of element-specific spectral lines.

[0034] In addition to the one associated with Fig. The design described in point 1 is implemented in the configuration of the Fig. 2. A further short-pulse laser beam, preferably with pulse energies in the range between 0.1 mJ and 1 J and repetition rates between 1 Hz and 1000 kHz, as well as wavelengths between 400 nm and 2000 nm, is coupled into the applicator (18). The laser beam (21) from a laser beam source (20) is transmitted via a beam guide (22) and a telescope (23) through two beam splitters (24, 24'). The reflected portion of the laser radiation is detected by two position sensors (25, 25'). The position sensors determine the propagation direction of the laser beam (21) within the applicator (18). They can be aligned to the optical axis of the applicator using position measurement via two automatically adjustable mirrors (not shown) in the beam guide system. The laser beam (21) is guided via the steel divider (24') to the beam splitter (5') and there it is superimposed with the processing laser beam (2) and the OCT measuring beam (8).The coaxial beams (26) are guided via the deflection element (13) to the beam deflection unit (14). Downstream of the beam deflection unit, the laser beam (21) is focused by a focusing optic (15) onto the surface of the bone (19) to excite LIBS plasma, exiting the applicator housing through an outlet opening. The beam deflection unit (14) distributes the foci of the three coaxial beams (26) in the processing plane on the bone (19) in the feed direction (x-direction) of the cutting process and perpendicular to it (y-direction). The plasma light (28) generated on the bone surface is collected by an optic (29) and guided via a beam guide (30) in the applicator (18) and a focusing optic (31) in a beam guide (32) outside the applicator (18) to a spectrometer (33). This generates LIBS spectra along the section line geometry, which are then used to characterize the tissue.The characterization serves in particular to differentiate between healthy and tumor tissue. As the ablation depth increases, the position of the laser focus of the laser beam (21) is shifted in depth (z-direction) by adjusting a lens (23') of the telescope (23, 23') that can be moved into the bone (19).

[0035] Fig. Figure 3 shows an exemplary embodiment of the proposed system. The laser applicator (18) is located at the end of an arm (36) of a collaborative robot (34). This robot consists of a base (35), an articulated arm (36) with arm segments rotatable relative to each other on motorized rotary joints (37), and a tool holder (38) at the end of the articulated arm. The articulated arm is rotatably mounted on the base. The tool holder has a rotational axis. The applicator (18) is attached to the tool holder (38) at the end of the articulated arm.

[0036] The surgeon can manually guide the laser cutting process across the bone surface. The collaborative robot (34) assists the surgeon in this process. While the surgeon guides the laser applicator (18) across the bone surface, the collaborative robot (34) automatically maintains a defined working distance from the bone surface, ensuring that the laser focus of the processing laser is on the surface to be cut. Furthermore, the collaborative robot (34) uses its force-torque sensors (43) in the rotary joints to determine the force and direction exerted by the surgeon in the feed direction. The collaborative robot (34) generates a counterforce with the motors in the rotary joints, thus stabilizing the applicator (18) at the laser processing site. At the processing site, the applicator performs a microscopic cut of defined width and length using its cutting function.Only when the residual thickness determined by the OCT system reaches a value predefined by the surgeon at all locations within this micro-cut does the collaborative robot release the feed and move the applicator in the direction of the force applied to the cutting edge of the micro-cut. This provides the surgeon with haptic feedback during a non-contact and inertial cutting process. The next micro-cut is then executed at the new cutting edge. Repeating this process generates a macroscopic cutting line. Combined with efficient bone removal, this results in a quasi-continuous cutting process.

[0037] The planning device (39) preferably used in the proposed system is equipped with surgical planning software. The surgical planning software receives preoperative image data of the patient. Using medical image processing software, the image data is segmented, and the anatomical structures, including those at risk (spinal cord, vital vessels) and those to be removed (tumors), are identified. Based on the preoperative data, the planning device suggests a cutting line (target trajectory). Alternatively, the surgeon can draw the target trajectory using a graphical user interface. In this example, the target trajectory is displayed on a VR display (40) within the patient's digital image data. During the cutting process, the VR display also shows the actual cutting margin and the current position of the laser focus.

[0038] In Fig.Figure 3 also indicates the navigation system (41), consisting of a stereoscopic camera and real-time image processing software. The navigation system determines the position of the applicator and the patient in space and assigns them to the preoperative image data. This assignment is achieved through a process called registration. Various established techniques can be used for this registration. For example, the applicator / laser focus can be positioned at defined locations on the patient within the surgical field, captured by the navigation system's camera, and then assigned to the corresponding locations in the planning system's digital image data. This allows the position of the applicator / laser focus relative to the patient and in relation to the preoperative image data to be determined if the applicator or patient moves.

[0039] The navigation system also transmits the applicator's position relative to the intended trajectory of the cutting line to the robotic assistance system. Based on this positional data, the assistance system defines a corridor within which the surgeon can move the applicator. This is intended to prevent excessive deviations from the intended trajectory and increase surgical precision and safety. The navigation system also allows the robotic assistance system to regulate the applicator's distance from the bone surface, ensuring that the laser focus is always on the surface being cut.

[0040] During hard tissue ablation in tumor surgery, LIBS measurements are preferably performed, and tumor tissue is diagnosed intraoperatively. The intraoperatively measured tumor distribution can be assigned to the surgical planning data via the applicator's navigation system. Detection of tumor tissue in the incision line leads to a recalculation of the target trajectory by the planning system and an adjustment of the robotic assistance system's movement corridor for the manual cutting process. In the VR display, the tumor distribution determined intraoperatively by LIBS measurements is shown, along with the actual incision line and the current position of the laser focus. Reference symbol list 1 Laser beam source 2 processing laser beam 3 Beam guidance 4.4' telescope 5.5' beam splitter 6.6' Position sensors 7 OCT sensor 8 OCT measuring beam 9 Beam guidance 10.10' telescope 11 Deflection element 12 coaxial beams 13 Deflection element 14 Beam deflection unit 15 Focusing optics 16 Exit opening 16' protective window 17 Handle on the laser applicator 17' atomizing nozzles 18 Laser applicator 19 bones 20 Laser beam source 21 Laser beam 22 Beam guidance 23 Telescope 24 beam splitters 25, 25' Position sensors 26 Coaxial beams 28 Plasma light 29 Optics 30 Beam guidance 31 Focusing optics 32 Beam guidance 33 spectrometers 34 Collaborative Robot 35 base 36 articulated arm 37 swivel joints 38 Tool holder 39 Planning Institution 40 VR display 41 Navigation system 42 Control 43 Force-torque sensors QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 2480153 B1

[0006] EP 3558150 A1

[0006]

Claims

[1] Laser surgical system for cutting hard tissue on an object (19), with - a laser applicator (18) that can be hand-held by an operator and that has or is connected to at least one dynamic 2D beam deflection device (14) by which a processing laser beam (2) can be guided over an area of ​​the hard tissue for cutting, and a measuring device (7) with which a cutting depth of a kerf produced with the processing laser beam (2) and a residual thickness of the hard tissue in the kerf can be measured, - a collaborative robot (34) with a robot arm (36) to which the handheld laser applicator (18) is attached, - a navigation system (41) with which the current position of the laser applicator (18) relative to the object (19) can be recorded, and - a control system (42) which controls the collaborative robot (34) during cutting based on data from the navigation system (41) and the measuring device (7) in such a way that the collaborative robot (34) maintains a cutting distance of the laser applicator (18) to the object (19) required for cutting via the robot arm (36) and only allows a feed movement of the laser applicator (18) along a cutting line by the operator when a cut that has just been made has been completed. [2] Laser surgical system according to claim 1, characterized by , that the control (42) controls the collaborative robot (34) during cutting based on the data of the navigation system (41) and data about a predetermined course of the cutting line in such a way that the collaborative robot (34) enables the feed movement of the laser applicator (18) only within a predefinable area along the cutting line by the operator. [3] Laser surgical system according to claim 1 or 2, characterized by , that the measuring device (7) is an OCT measuring device. [4] Laser surgical system according to claim 3, characterized by , that the OCT measuring device (7) directs a measuring beam (8) coaxially to the processing laser beam (2) onto the hard tissue to measure the cutting depth and the residual thickness of the hard tissue. [5] Laser surgical system according to any one of claims 1 to 4, characterized by , that the laser applicator (18) has or is connected to a spectroscopic measuring device (20, 33) which makes it possible to characterize tissue during cutting and thereby to distinguish different tissue types from one another, in particular to detect tumor cells in hard tissue. [6] Laser surgical system according to claim 5, characterized by, that the spectroscopic measuring device (10, 33) directs a laser beam (21) coaxially to the processing laser beam (2) onto the hard tissue to excite a plasma for generating a LIBS spectrum and has a detection beam path with collecting optics (29), beam guidance unit (32) and a spectrometer (33) for a spectral analysis of emitted plasma light. [7] Laser surgical system according to one of claims 1 to 6, which additionally comprises a planning device (39) which, based on preoperative image data of a patient, receives information about the location and extent of the tumor in the object (19) and, based on this information, calculates a target trajectory for the cutting line, wherein the control (42) controls the collaborative robot (34) during cutting based on the data of the navigation system (41) and the calculated target trajectory in such a way that the collaborative robot (34) restricts the movement of the laser applicator (18) by the surgeon in such a way that, on the one hand, healthy tissue away from tumor tissue on the object (19) is protected and, on the other hand, the processing laser beam (2) is prevented from cutting into tumor tissue. [8] Laser surgical system according to claim 7 in combination with claim 5 or 6, characterized by, that the planning device (39) is designed in such a way that, in the event of detection of tumor tissue by the spectroscopic measuring device (20, 33) during cutting, it recalculates the target trajectory for the cutting line. [9] Laser surgical system according to any one of claims 1 to 8, characterized by , that the laser applicator (18) is connected to a flexible or articulated beam guidance device via which the processing laser beam (2) is coupled into the laser applicator (18). [10] Laser surgical system according to claim 9, characterized by , that the measuring device (7) and, if applicable, the spectroscopic measuring device (20, 33) are connected to the laser applicator (18) via the flexible or articulated beam guidance device. [11] Laser surgical system according to any one of claims 1 to 10, characterized by, that the laser applicator (18) has a spray device (7') with which a film of liquid can be applied to the hard tissue during cutting, moistening and cooling the hard tissue.

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