Device for safe cutting of biological tissue

Abstract

The invention relates to a device for cutting biological tissue during a surgical intervention and the use of the device. In particular, the cutting is performed safely by means of a laser without compromising the actuation speed thereof. The device combines information about the laser, information about the tissue and information about the user in order to apply safety measures.

Description

Technical Field

[0001] This invention relates to an apparatus for cutting biological tissue during surgical intervention and the use of the apparatus. Specifically, cutting is performed safely using a laser without compromising its actuation speed. The apparatus combines information about the laser, information about the tissue, and information about the user to apply safety measures. Background Technology

[0002] In surgical applications, laser-based devices offer significant advantages over conventional mechanical tools such as scalpels, saws, drills, or piezoelectric tools. Among these advantages are precision, the ability to cut arbitrary geometries, the absence of vibration, better tissue recovery, and the lack of contact. However, the lack of contact also presents the disadvantage of losing tactile feedback, thus compromising control over the depth of the cut.

[0003] When using mechanical instruments routinely used in surgery, the surgeon does receive tactile feedback and can continuously control the depth of the cut to be performed. Therefore, the actuation of mechanical tools is always spatially constrained, resulting in the tool only modifying the portion of the tissue in physical contact. In contrast, in laser-based devices, the laser propagates in a straight line and can act on tissue without any contact, thus limiting control of the cut; that is, the laser has no actuation point but a direction of actuation. Therefore, there are significant problems in ensuring the safety of laser cutting in surgical applications.

[0004] Some solutions to this problem in the prior art attempt to estimate the location where the laser can penetrate based on measurements of the surface of the tissue to be cut. In this type of solution, the process is performed by combining the measurements of the tissue surface with the cutting of the tissue during an iterative verification process. This has significant drawbacks in terms of the total duration of the cutting procedure, making these solutions quite impractical in actual surgery.

[0005] Furthermore, in some of these solutions, tissue cutting is performed at a single point, with the cutting continuing at that location until the end is reached, and movement to the next cutting position is only performed once the current cut is completed. A drawback of this is that measuring the surface of the tissue can become extremely difficult in deep, narrow single holes or when there are irregular or angular shapes on the surface.

[0006] Furthermore, these solutions suffer from another set of drawbacks: they cannot guarantee the safety of tissue cutting because they do not adequately define the initial area where one or more tissues will be cut, or they do not define the ends of the tissue to be cut at all, or they do so with low precision, or they are only applicable to tissues with specific characteristics (e.g., hard tissue) (in which case additional image processing techniques are required), or they limit the application of the solutions in very specific surgical procedures. These limitations in the definition of tissue cutting safety mechanisms can lead to unsuitable cuts, resulting in unsatisfactory surgical procedures. Summary of the Invention

[0007] The present invention provides a solution to the aforementioned problems by means of a biological tissue cutting method according to the present disclosure and the use of the device according to the present disclosure. The dependent claims define preferred embodiments of the invention.

[0008] A first aspect of the present invention provides a biological tissue cutting device, comprising: - A laser emitter suitable for cutting biological tissue in the area; - A controller that communicates with the laser emitter and is used to activate and deactivate the laser emitter; - An optical module suitable for defining the surface of tissue in an operating mode; - A central processing unit that communicates with the controller and the optical module, and is suitable for: Define the pre-established cutting depth of the laser emitter; Define at least one reference surface; A numerical model of the generated region is provided, which includes at least the shape of the surface of the tissue in the region, the shape of at least one reference surface (under which cutting is prohibited), and the direction of the laser beam oriented by the laser emitter. If, in the numerical model, a point corresponding to the line representing the laser beam and spaced at a distance equal to the cutting depth from the intersection of the line and the surface of the tissue, is located outside the forbidden region, then the laser emitter is activated. The forbidden region is any part of the tissue in the region that is prohibited from being cut.

[0009] A first aspect of the invention defines a biological tissue cutting apparatus capable of ensuring safety during cutting without affecting the speed of the procedure. In one example, the apparatus according to the invention cuts a volume of biological bone tissue measured as 10 × 10 × 10 cubic millimeters in a range of 50 seconds to 400 seconds.

[0010] The cutting apparatus includes a laser emitter (i.e., a laser beam or simple laser) that communicates with a controller to activate or deactivate the laser emitter. Preferably, the laser emitter is an Er:YAG type laser emitter with a conventional generation wavelength of 2940 nm. To ensure safety during cutting, the surface of the tissue to be cut must be known; therefore, the tissue cutting apparatus also includes an optical module. The optical module is based on optical topology techniques, including, for example, optical coherence tomography systems, or structured light, or stereolithography, or hybrid techniques including, for example, photoacoustic tomography systems. Furthermore, the optical module includes computational means capable of identifying the shape of the tissue surface based on measurements performed by the optical or photoacoustic systems.

[0011] Furthermore, the cutting device includes a central processing unit that communicates with the controller and the optical module. Throughout this specification, the central processing unit will be understood as a unit capable of receiving and transmitting data, as well as processing said data. In a preferred example, the central processing unit is a processor or a microprocessor.

[0012] On one hand, the central processing unit defines a pre-established cutting depth for the laser emitter, which is understood as the depth to which the laser can cut, measured from the location of the intersection of the defining laser line and the biological tissue. Preferably, the cutting depth of the laser emitter is between 50 micrometers and 200 micrometers.

[0013] On the other hand, the central processing unit defines at least one reference surface under which cutting is not permitted. The one or more reference surfaces are defined considering different criteria, such as the division of tissue ends, the division of tissue origins, a pre-established maximum depth, or a pre-established maximum flatness level. Furthermore, the reference surfaces are dynamic; that is, new reference surfaces can be added, and pre-existing reference surfaces can be modified and / or eliminated throughout the surgical intervention.

[0014] The shapes of these reference surfaces, as well as the shapes of the tissue surfaces determined by the optical module, are imported into a numerical model generated by the central processing unit. Surfaces corresponding to physical entities obtained by means of measuring devices, such as tissue surfaces, or virtual surfaces, such as user-defined reference surfaces, can be represented in the numerical model. Furthermore, the numerical model includes the direction of the laser beam for laser orientation. The numerical model allows for the determination of intersection points and / or conditions upon which decisions can be made. In a preferred example, the numerical model is computationally depicted using a data structure that at least allows defining domains and geometric entities associated with the laser surface and actuation lines.

[0015] This numerical model allows for determining whether the laser must be activated based on whether safety criteria based on one or more defined reference surfaces are met. As a result of the numerical model, the location of a point representing a straight line of laser beam is determined, spaced equidistant from the intersection of the same line with the surface of the tissue at a distance equal to the cutting depth. The central processing unit then estimates whether said location lies within a prohibited region, which is understood to represent any portion of the tissue where cutting is prohibited. Specifically, the prohibited region is a tissue region existing beneath a reference surface.

[0016] This prevents laser cutting of tissue or parts of the area that are not the target of the surgery. These safety measures are important, especially when the non-target tissue is particularly important, such as nerves, the dura mater, or blood vessels.

[0017] It should be noted that if there is more than one reference surface, these surfaces must be considered together; that is, the activation and deactivation of the laser will depend on all of these surfaces simultaneously. Therefore, when one reference surface does not meet the laser activation criteria, the central processing unit will not activate the laser even if the remaining reference surfaces meet the activation criteria.

[0018] Therefore, with the aid of the device of the first aspect of the invention, the central processing unit controls the activation of the laser, excludes prohibited areas, and allows the process to continue without delay in the remaining areas. This keeps the laser in a ready state, but only acts on the areas where treatment must be applied.

[0019] The cutting and measurement performed by the optical module are executed continuously in a collaborative and independent manner by a central processing unit. The unit updates the information received from the optical module to dynamically determine the surface of the tissue again during the cutting process.

[0020] Therefore, this invention proposes simultaneous operation of the laser and optical module, a feature contrary to the teachings of the prior art. Lasers affect tissue, degrading measurements performed by the optical module; thus, the trend to date has been to avoid simultaneous laser use. For example, laser cutting can result in the generation of smoke, bone dust, vibration, or sparks, thereby altering the measurement results of the optical module. Furthermore, to ensure cooling and cleaning of the surgical area, continuous or cyclical application of spraying, rinsing, blowing, suction, or any combination of these operations can also interfere with measurements performed by the optical module. However, the device of this invention only needs to determine the surface of the tissue, and this determination is robust even in the presence of the operating laser cutting as well as cleaning and cooling fluids; therefore, the effects of changes caused by laser operation on the measurements of the optical module do not hinder robust identification of the shape of the tissue surface, and advantageously, significantly reduce the process time.

[0021] In one embodiment, the central processing unit is further configured to deactivate the laser emitter if, in the numerical model, at least one of the points located between the intersection of the straight line representing the laser beam and the surface of the tissue, and the intersection plus a distance equal to the cutting depth, coincides with the location of at least one point in the prohibited region.

[0022] In this embodiment, the central processing unit estimates the position of a segment of the straight line (which represents the laser beam) based on a numerical model, and checks whether at least one point of the segment is located within a prohibited area. If at least one point of the segment is located within the prohibited area, it deactivates the laser. Otherwise, the central processing unit activates the laser.

[0023] This section includes a point located between the intersection of the straight line representing the laser beam and the surface of the tissue, and the intersection plus a distance equal to the cutting depth.

[0024] In one embodiment, the central processing unit is further configured to deactivate the laser emitter if, in the numerical model, none of the points on the straight line (which represents the laser beam) coincide with the points on the surface of the tissue.

[0025] For safety, the central processing unit deactivates the laser at a specific location if it does not intersect the surface of the target tissue at the stated location. For example, if the laser is incorrectly positioned outside the surgical area, it will not hit the target tissue when activated; instead, it may damage other tissues of the patient that should not be treated, or even harm medical personnel.

[0026] In this embodiment, the option that the optical module fails to detect any tissue is also considered, for example, because the device has been turned on prematurely and the patient is not yet on the operating table, or simply because of a malfunction in the optical module. Under these conditions, laser cutting must be stopped to prevent accidents.

[0027] In one embodiment, at least one reference surface is: - The boundary surface of the ends of the tissue that divides the region; or - Using the tissue of the region (whose surface has been determined by the optical module) as a reference, delineate the boundary surfaces of the starting points of different tissues, with each tissue located deeper than the tissue of the region; or - Using the tissue of the region (whose surface has been determined by the optical module) as a reference, the boundary surfaces of the ends of different tissues are divided, with each tissue located deeper than the tissue of the region; or -A combination of any of the aforementioned surfaces.

[0028] As described above, different standards are considered to define one or more reference surfaces. In this embodiment, the reference surface is the boundary surface that delineates the end or beginning of a tissue, whether the tissue is one whose surface has been determined by the optical module (referred to as the primary tissue) or the tissue adjacent to it.

[0029] For example, in spinal surgery, the area to be cut by the laser will comprise a mixture of tissues consisting of at least one vertebra, soft tissue, blood vessels, and other adjacent or underlying structures, such as the dura mater protecting the dural sac surrounding the spinal cord and spinal nerves. In this case, at the start of the surgery, the primary tissue may be the vertebra, the surface of which has already been determined by the optical module. One possible reference surface is the distal end of said vertebra. Alternatively or simultaneously, the reference surface or other reference surface may be the surface that divides any soft tissue or the origin or distal end of a nerve adjacent to the vertebra. In another, more advanced stage of the surgery, the primary tissue may be the ligamentum flavum, and a possible reference surface is the distal end of the ligamentum flavum or the origin of the dural sac.

[0030] The central processing unit defines these boundary surfaces based on received information about anatomical structures present in the surgical area. This information may come from preoperative and / or intraoperative images, and / or measurements performed by the optical module.

[0031] In one embodiment, at least one reference surface is determined by means of preoperative images, preferably by means of magnetic resonance images, computerized axial tomography images, or fluorescence fluoroscopy images.

[0032] The anatomy of a patient known to require surgery is the result of one or more medical imaging techniques, typically MRI, computed tomography, or fluoroscopy performed before and / or during surgery. This plan can indicate that certain elements in the volume do not need to be treated because they may belong to critical structures such as the dural sac, nerves, or blood vessels.

[0033] The image is processed and segmented to define only the volume of the primary tissue of interest. As a result, the boundaries between the primary tissue and adjacent tissues are appropriately distinguished, and this information is converted into at least one reference surface by the central processing unit.

[0034] Alternatively, or to supplement the foregoing information, the optical module may also identify one or more surfaces that will distinguish the tissues from each other, so that the central processing unit will be able to define a reference surface.

[0035] Using the one or more reference surfaces, one or more tissues that can be cut with a laser can be distinguished from those that cannot be cut, thereby ensuring the safety of the cutting process.

[0036] In one embodiment, at least one reference surface determined by means of preoperative images is the boundary surface of the end of the bone tissue dividing the region.

[0037] In certain types of surgery, similar to the aforementioned spinal surgeries, the target area is bone. Specifically, osteotomy or bone removal used in laminectomy and laminatomy are common stages in decompression and stabilization surgeries. With the help of preoperative images, the boundaries of this type of tissue, such as soft tissues like the ligamentum flavum, dural sac, and nerves, can be visualized relative to adjacent tissues.

[0038] Therefore, assuming that only the vertebra is cut in this type of process, defining the reference surface as the boundary surface that divides the end of the vertebra is a highly reliable safety standard to prevent adjacent tissues from being affected by the cut.

[0039] Following osteotomy of one or more sections of the vertebra, another common stage of the aforementioned spinal surgery is the removal of soft tissue, typically the ligamentum flavum or yellow ligamentum, located between the bone and the dural sac. The aim is to decompress the nerves and remove spinal stenosis, releasing it from the pressure source causing pain. During this procedure, the distal end of the ligamentum flavum, the surface of the dural sac, or any other combination of the initial or final surfaces of tissues present in the anatomical region of interest can be used as reference surfaces.

[0040] In one embodiment, at least one reference surface is a flat surface that is substantially parallel to the focal plane of the laser emitter and / or the focal plane of the optical module.

[0041] In this embodiment, one or at least one reference surface is a flat surface that defines the maximum permissible cutting level. This surface is substantially flat and parallel to the focusing plane, whether it is the focusing plane of the laser or the focusing plane of the optical module. Preferably, the two focusing planes coincide with each other. Throughout this document, the focusing plane will be understood as a plane perpendicular to the optical axis on which the laser emitter and / or optical module achieves its optimal spatial resolution or focus point.

[0042] Preferably, the maximum level is selected by the surgeon and received by a central processing unit that converts the information into a reference table. Furthermore, the maximum level can be dynamic, meaning its depth can be gradually updated as the surgical intervention progresses. Throughout the document, when the term "surgeon" is used, it can be understood to refer to any user or healthcare professional authorized to perform a surgical intervention.

[0043] Preferably, the cutting laser gradually sweeps across the biological tissue until the surface is smoothed, taking into account a tolerance range; if the surface is smoothed beyond this range, it is considered successfully smoothed. For safety, this progress and smoothing during tissue cutting is always performed without violating the defined flat surface. According to this actuation mode, the laser beam acts more frequently on points on the surface with higher elevations.

[0044] In addition, this type of reference surface offers several related technical advantages, which stem from the fact that both the laser and the optical module have a measured optimal focal plane.

[0045] On the one hand, when the tissue in the area has been smoothed, measurements from the optical module are obtained under favorable conditions because the optical module can be optimally focused without any high irregularities that could reduce the measurement results or create shadowed areas, thus allowing for measurements of the sample surface to be performed under the most favorable conditions. Furthermore, the smoothness of the tissue allows the laser to focus better on the tissue and encounter an unobstructed surface, which translates into more efficient cutting. Finally, providing a smooth cutting area facilitates other tasks, although these tasks are not part of the surgery but are absolutely necessary for its success, such as performing irrigation during surgery to keep the surgical area clean and prevent thermal damage.

[0046] In one embodiment, at least one reference surface is a surface having a maximum depth determined from the surface of the tissue.

[0047] In this embodiment, one or more reference surfaces are surfaces having a depth that represents the maximum permissible cutting depth point-by-point based on the surface of the tissue determined by the optical module.

[0048] The surface with depth can be defined based on the tissue surface of the area initially determined by the optical module or at any other time during surgery on the surface of the tissue where a renewal procedure has already taken place.

[0049] Advantageously, this type of reference surface constitutes a safety device for preventing tissue from being cut at a depth greater than that defined by the central processing unit, thereby preventing the cutting of tissue other than the target tissue.

[0050] In one embodiment, at least one reference surface is: - The boundary surface of the ends of the tissues that divide the region; and / or - Using the region's tissue as a reference, demarcate the boundary surfaces of different tissues whose origins have been determined by the optical module, with these different tissues located deeper than the region's tissue; and / or - Using the region's tissue as a reference, demarcate the boundary surfaces of the ends of different tissues, whose surfaces have been determined by the optical module, where the different tissues are located deeper than the region's tissue; and / or - A flat surface that is substantially parallel to the focal plane of the laser emitter and / or the focal plane of the optical module: and / or - A surface having a maximum depth determined from the surface of the tissue.

[0051] The reference surface can be a single surface of any surface defined according to the foregoing embodiments, or a set of reference surfaces that must be considered simultaneously. Therefore, the device according to the invention considers a variety of safety options applicable to each specific procedure.

[0052] In one embodiment, the central processing unit defines at least one reference surface with a safety margin.

[0053] Although it is true that laser cutting is far more precise than cutting with conventional surgical instruments, the device of the present invention takes into account safety margins on all reference surfaces to further increase the safety of the method and prevent cutting non-target tissue at any time.

[0054] Furthermore, the safety margin can be dynamic, meaning that the safety margin can gradually change throughout the entire surgical intervention.

[0055] The safety margin is understood as representing a pre-established distance such that: if the laser beam cannot cross the reference surface, it is determined whether the point that crosses the reference surface is a point spaced apart from the pre-established distance, thereby preventing it from reaching the reference surface. In this case, the safety margin is equivalent to assuming that the reference surface has moved a pre-established distance toward the emission source.

[0056] In one embodiment, the central processing unit includes an input device for inputting a definition of the safety margin of at least one reference surface.

[0057] The surgeon or medical personnel in charge of the operation can select this range, and they transmit the values ​​of these ranges to the central processing unit via an input device. Conversely, the central processing unit takes into account the ranges in the numerical model to define or update one or more reference surfaces.

[0058] In one embodiment, the optical module includes an optical coherence tomography (OCT) system.

[0059] Throughout this specification, the OCT system will be understood as an optical system capable of determining the volume of a region of biological tissue to be cut by illuminating the area with a partially coherent source (typically a superluminescent diode or scanning source). Based on this information obtained from the OCT system, the optical module identifies the surface of the target tissue or primary tissue.

[0060] In one embodiment, the optical coherence tomography system is a polarization-sensitive optical coherence tomography (PS-OCT) system.

[0061] More specifically, in this embodiment, the OCT system that incorporates the optical module is a polarization-sensitive optical coherence tomography (PS-OCT) system. This type of system is characterized by its measurements taking into account how tissue can alter the polarization state of the light reflected from it.

[0062] Advantageously, this type of system provides extremely robust measurements because it performs post-processing on the light reflected by the tissue, making the reflectivity or intensity signal insensitive to polarization changes caused by the tissue, thus providing optimal contrast regardless of polarization effects generated within the tissue. This allows for robust determination of the tissue surface. Furthermore, considering its different responses to polarization, tissues that cannot be distinguished by OCT can be precisely distinguished using PS-OCT, thereby identifying previously undetectable restricted areas.

[0063] As described above, preferably, the cutting laser gradually sweeps across the biological tissue until its surface is flattened. Under these conditions, the optical module system (e.g., a PS-OCT system) performs measurements optimally because the flattened surface places the tissue in the system's focal plane. Similarly, the laser emitter operates optimally when the tissue's flat surface is in its focal plane.

[0064] In one embodiment, the optical module includes the following system: - Structured light system; or - Three-dimensional alignment system; or - Photoacoustic tomography system.

[0065] As an alternative to OCT and PS-OCT systems, the optical module may include another type of optical system (structured light or stereo pair) or photoacoustic system (photoacoustic tomography), such as those mentioned above.

[0066] In particular, structured light systems typically use infrared light to illuminate tissue, and the projector produces, for example, a spatial pattern of squares. The light pattern is deformed according to the shape of the surface, so if the pattern on a flat surface is known, the shape of the surface can be inferred from the image of the deformed pattern.

[0067] Stereoscopic systems typically use infrared light sources to irradiate tissues and reconstruct the tissue volume using stereoscopic techniques.

[0068] In contrast, photoacoustic tomography systems use lasers to illuminate tissues and employ ultrasound transducers for measurement.

[0069] In one embodiment, the laser emitter includes a scanner that changes the direction of the laser beam to aim the laser beam at different points in the area.

[0070] The scanner moves a laser across a pre-defined scanning area or pattern. Preferably, the pattern is uniform. In one example, from the perspective of the surgeon performing the procedure, the pattern is created from the surgeon's left to right and from top to bottom.

[0071] In the prior art, a known solution involves establishing a cut at each location so that the laser does not proceed to the next location until the cut at one location has been completed. However, in the context of this invention, this type of solution is not optimal for the operation of the optical module, as measurements can become extremely difficult or even impossible in cases of deep, narrow single holes or complex angles or shapes on the tissue surface. Therefore, gradually advancing over the entire area rather than at a single point facilitates measurements by the optical module, thus aiding in the definition of the tissue surface throughout the procedure. Additionally, it helps the surgeon observe the surgical area and gradually reach the surgical stage closest to critical tissues, ensuring consistent access and improved safety.

[0072] In this process, which is performed in a repetitive and continuous manner, the laser can interact with areas that do not need to be treated (i.e., the forbidden zones mentioned above). Preferably, in this case, the scanner allows the laser to be redirected toward the area containing the target tissue, excluding the forbidden areas. Therefore, the laser does not cool down and continues the cutting procedure under optimal conditions without delay, thereby minimizing the time required to perform the cut.

[0073] Alternatively, the scanner allows the laser to continue the predetermined pattern by scanning through prohibited areas, but the central processing unit prevents the laser from being activated, thereby preventing the laser from cutting non-target tissue.

[0074] In one embodiment, the central processing unit is adapted to perform a continuous scan of a laser beam emitted by a laser emitter over a region until at least one reference surface is reached.

[0075] In this embodiment, the central processing unit causes the laser to scan until it reaches one or more reference surfaces.

[0076] For example, when the reference surface is a flat surface that defines a maximum cutting level, the central processing unit causes the laser to scan until the maximum level is reached. If the depth of the horizontal position increases at that point, the central processing unit continues scanning with the laser.

[0077] In another example, when the reference surface is the boundary surface that divides the ends of the bone, the central processing unit causes the laser to scan until it reaches the end surface of the bone. In a more specific example, a safety margin is further applied, and the central processing unit causes the laser to scan until a remaining thickness equal to the safety margin remains throughout the bone.

[0078] In one embodiment, the optical module includes a light source and a scanner that changes the direction of the light source to align it with different points in the area.

[0079] In this embodiment, the optical module includes an OCT system, a PS-OCT system, or a photoacoustic tomography system, which in turn includes a light source. To scan the region of interest, the optical module also includes a scanner that focuses the light source at different points within the region.

[0080] Advantageously, as the cutting progresses during surgery, the light source of the optical module focuses on a point in the tissue where the new surface is located, enabling the central processing unit to accurately redefine the surface in the numerical model.

[0081] In one embodiment, the central processing unit is adapted to perform continuous scanning of the light source of the optical module over a region.

[0082] In this more particular embodiment, the central processing unit controls the aforementioned scanning of the light source.

[0083] In one embodiment, the control of the scan established by the laser emitter and the scan established by the optical module are independent.

[0084] Although the scanning of the laser emitter and the scanning of the optical module are controlled by the central processing unit, the two scans are independent of each other. Therefore, the parameters defining each scan (e.g., speed) are completely independent of each other, so a scan can be stopped or modified without affecting other scans.

[0085] The scanning of the optical module may require, for example, a lower scanning frequency, in order to update the information about the tissue appropriately.

[0086] In one embodiment, scanning of the light source of the optical module is performed over the region when the following obsolescence criterion is met: -After the pre-established time period has passed - Before the laser emitter is activated or deactivated by the central processing unit.

[0087] As mentioned above, the cutting path and measurement of the optical module are performed independently; therefore, the cutting path and measurement of the optical module do not necessarily have to be in a straight line with each other.

[0088] Although the optical module performs continuous measurements, errors may occur when the module scans the region of interest, or measurements may be taken over excessively long periods. Therefore, the information upon which the numerical model is based at a given time may be outdated, potentially leading to incorrect tissue cutting and endangering the surgery.

[0089] To prevent this, the device provides an update of measurements by the optical module in critical situations, especially when a predefined time period has elapsed. This prevents any problems from occurring during the refresh of measurements and before the central processing unit activates or deactivates the laser emitter, ensuring that the tissue whose information is updated in the numerical model is being cut or not cut.

[0090] In one embodiment, in the numerical model generated by the central processing unit, at least one flat surface is progressively established at multiple depth levels with reference to the focal plane of the laser emitter and / or the focal plane of the optical module, such that when the surface of the tissue descends to the depth of the flat surface due to the action of the laser from the laser emitter, at least one flat surface becomes a deeper depth.

[0091] When at least one reference surface is a flat surface parallel to the focal plane (i.e., the focal plane of the laser emitter and / or the focal plane of the optical module), the surface is defined at a specific depth. As the laser reaches the flat surface defined at a given time, this depth can be progressively advanced, such that the flat surface is updated at a depth greater than the previous depth.

[0092] Therefore, multiple levels with different depths were defined, which allowed for gradual cutting in sections where safety was ensured.

[0093] Multiple levels can be fixed (i.e., predetermined before the start of surgery) or dynamic (i.e., the flat surface is gradually updated as the surgery progresses). In one particular example, the depth difference between successive horizontal positions is constant. In another example, the depth difference between successive horizontal positions is variable. In yet another example, the surgeon determines the new depth of the flat surface during surgery and inputs its value via an input device in the central processing unit, which transforms this information into a new, updated flat surface and assigns it to a numerical model.

[0094] In one embodiment, the central processing unit includes an input device for inputting the definition of at least one reference surface assigned to the numerical model.

[0095] As mentioned throughout the document, surgeons or medical personnel may make different decisions regarding the reference surface before and during surgical intervention. These decisions must be considered by a central processing unit, which analyzes the received information and uses it to define the reference surface and assign it to the numerical model.

[0096] Preferably, the input device is equipped with an interface that enables the central processing unit to interact with surgeons, medical personnel, or users.

[0097] In one embodiment, the central processing unit includes an input device for inputting a definition of a region to be avoided, the shape of which is assigned to a numerical model; and the central processing unit is further configured to deactivate the laser emitter if, in the numerical model, at least one of the points located between the intersection of a straight line (which represents a laser beam) and the surface of the tissue, and the intersection plus a distance equal to the cutting depth, coincides with the location of at least one point in the region to be avoided.

[0098] In addition to prohibited areas, for safety reasons, users, surgeons, or medical personnel can decide which other types of specific areas cannot be cut with a laser before or during surgery, for example, when the presence of a critical structure that is not within a prohibited area is identified during surgery.

[0099] In these cases, the central processing unit includes additional input devices from which the user can define areas to be avoided, which are understood to represent specific areas that cannot be cut with a laser. Preferably, these input devices are interfaces.

[0100] In a preferred example, to avoid planar views of surgical areas defined by cuts at arbitrary depths, all points with x and y coordinates belonging to the defined area are completely prohibited. The x and y coordinates must generally be interpreted as coordinates identifying specific points on the surface, regardless of how the surface is parameterized. In a specific example using a Cartesian coordinate system, the x and y coordinates correspond to the x and y axes.

[0101] This information is received by the central processing unit (CPU) responsible for processing it, which then assigns the shape of the region to be avoided to the CPU of the numerical model. Furthermore, the CPU is configured to deactivate the laser emitter if the laser beam penetrates the region to be avoided according to the established cutting depth.

[0102] In one embodiment, the device includes a surgical area display device, preferably a screen that displays RGB video images.

[0103] To provide the user with visual information throughout the surgical intervention, the device includes these display devices. In a preferred example, the display device is a screen or monitor that shows the surgeon a video image of the surgical area in a plan view, particularly an RGB image. An RGB image must be understood as an image whose colors can be defined by means of a standard RGB color model.

[0104] Furthermore, if deemed necessary, the display device advantageously assists the user or surgeon in selecting areas to avoid. The user draws the areas to avoid within the context of an image displayed on the display device, preferably an RGB video of the surgical area shown in a plan view. In these cases, cutting of any depth is prohibited at all points belonging to the area defined by the image shown on the display device at both the "x" and "y" coordinates.

[0105] In one embodiment, the surgical area display device also displays information about the distance from each point on the surface of the tissue to at least one reference surface.

[0106] To provide an additional source of visual information about the target area approaching the surgery, in this embodiment, the surgeon is informed of the distance from each point on the tissue surface to a reference surface. If more than one reference surface exists, the distance to the reference surface closest to each point is calculated. This additional information is applied to the image displayed in the surgical area display device.

[0107] The central processing unit calculates the distance based on a numerical model and displays the distance via a surgical area display device.

[0108] In one embodiment, the central processing unit is further configured such that, during the cutting process, when the laser emitter scans a set of points in the area, whenever a point sequentially reaches a point where the laser emitter's emission is blocked, the laser emitter positions itself to the next point where emission is permitted, without stopping the emission of the laser beam.

[0109] To prevent delays in the process, when the laser of the device is about to hit a point that cannot be cut, the central processing unit redirects the laser to another area containing the target tissue, that is, to another area that must be cut. Preferably, the laser is redirected by means of a scanner included in the optical module.

[0110] According to this embodiment, advantageously, not only is the time when the laser is not activated avoided, but by jumping to another point where it can continue to work, the laser will not cool down and will remain in optimal operating conditions.

[0111] Alternatively, the central processing unit instructs the laser emitter to scan all points in the area, but only activates it at those points where cutting is permitted.

[0112] In one embodiment, the central processing unit is further configured to define a function representing a scalar of temperature levels among a set of points in a region having a specific pattern, wherein: - The function initially uses a pre-established reference value; - Whenever the laser emitter hits a point in the pattern, the function increments that point by a first pre-established increment value; - The value of all points is reduced by the second pre-established increment value in each pre-established time period; - For each point in the pattern, if the value of that point exceeds a pre-established threshold, the point is designated in the numerical model as a point that is not allowed to be cut as long as the value remains above the threshold.

[0113] When the cutting area is very small, the laser may act on these areas in a largely continuous manner, causing thermal damage. Therefore, although the process can begin in a wide actuation zone, increasingly larger forbidden zones and optional avoidable zones may appear during the cutting process. Consequently, the area to be cut becomes smaller and smaller, and the laser penetrates said zone more and more frequently, thus increasing the power per unit surface area during the process. When this power exceeds a certain threshold, the tissue begins to suffer burns.

[0114] In the prior art, to prevent any thermal damage caused by tissue heating during laser cutting, the cutting area needs to be cooled by rinsing or spraying. Therefore, the trend until now has been to perform tissue cutting and optical module measurements alternately, rather than using the laser emitter and optical module simultaneously. However, as described throughout the specification, the present invention does contemplate the simultaneous use of a laser and an optical module as embodiments.

[0115] The apparatus according to this embodiment considers adjusting the power per unit surface of the laser so that it does not exceed a predetermined threshold. This threshold can be a dynamic threshold or can be gradually changed throughout the surgical intervention. In one example, the user, surgeon, or medical personnel selects the threshold at a given time during the procedure and inputs it via an input device of a central processing unit, preferably an interface.

[0116] This thermal protection is based on a simplified tissue temperature model that takes into account the point-by-point tissue heating and cooling based on the number of laser pulses allowed per unit time.

[0117] In this model, a scalar reflection of temperature at a point in the tissue is defined. This scalar increases in a fixed increment each time a laser is emitted, such that if a predetermined threshold is exceeded, the numerical model considers that the point is not permissible for cutting as long as the associated temperature scalar remains above the threshold.

[0118] As described above, the model also takes into account tissue cooling, so that as a predetermined time period passes, the scalar quantity at each point in the tissue decreases by a fixed amount (equal to or different from a fixed increment). This time period can be a fixed or dynamic period during the operation. Furthermore, the surgeon or medical personnel can select this value at a given time during the operation, and the surgeon or medical personnel will input this value into the central processing unit via an input device, preferably an interface.

[0119] In one embodiment, the central processing unit is further configured such that during cutting, when the laser emitter scans a set of points in the region, priority is given to points with a cutting depth less than other points in the scanning sequence to compensate for the cutting depth.

[0120] As described above, one method of laser cutting a target area can be performed using a control mode that adjusts the laser activation to achieve a cross-section that always has a flat bottom. Therefore, during the cutting process, there will be areas that are deeper than other areas.

[0121] To achieve a flat bottom surface, in this embodiment, the central processing unit is configured to prioritize shallower points, deactivating the laser at deeper points or regions and activating it at shallower points or regions. According to another embodiment, jumping from one point to another is performed without deactivating the laser, but by irradiating these points multiple times at higher heights. In this way, the surface area becomes increasingly deeper while the deeper regions remain unchanged, until all points eventually have the same horizontal position.

[0122] In one embodiment, the central processing unit includes means for stopping the emission of the laser emitter, the means being adapted to stop the emission of the laser emitter when the laser emitter is in operation.

[0123] The apparatus of the present invention also considers the option to stop laser actuation under any conditions, even if other safety criteria defined above are not met.

[0124] Therefore, the central processing unit receives stop commands from an external source, preferably issued by the user or surgeon. Advantageously, cutting safety is ensured when medical personnel deem it necessary to stop the cutting for any reason.

[0125] In one embodiment, the biological tissue cutting apparatus further includes a fluid management unit adapted to provide, in operating mode, flow of gas, liquid, or a mist of gas containing liquid particles in a region containing a biological tissue on which a laser emitter acts.

[0126] Tissue cut by this device tends to bleed continuously, and the cutting operation itself also continuously generates particles and solid residues that must be removed from the laser-actuated area.

[0127] In this embodiment, in addition to laser cutting, the device has cleaning capabilities. To this end, the device includes a fluid management unit that provides a flow of gas, liquid, or mist capable of removing unwanted components present in the area containing the tissue region to be cut by the laser emitter.

[0128] Preferably, the flow of gas, liquid, or mist is provided via a conduit connecting the fluid management unit to the surgical area.

[0129] Advantageously, on the one hand, the laser can be applied to tissue areas free of blood and / or unwanted particles that might affect cutting accuracy; on the other hand, the measurement accuracy of the optical module remains unaffected, allowing it to be determined that the actual surface of the target tissue is free of these unwanted components.

[0130] The second aspect of the invention provides the use of the device of the first aspect of the invention in minimally invasive robot-assisted surgery. Attached Figure Description

[0131] These and other features and advantages of the invention will become more apparent from the following detailed description of preferred embodiments given only by reference to the accompanying drawings and illustrative and non-limiting examples.

[0132] Figure 1 A conventional diagram of an apparatus according to an embodiment of the present invention is shown.

[0133] Figure 2 The diagram shows a cut of the tissue surface determined by the optical module and graphs of three different reference surfaces.

[0134] Figure 3 This illustrates an example of how the central processing unit prioritizes points for cutting over other points to smooth the surface of the tissue.

[0135] Figure 4 This illustrates a scenario where the central processing unit disables the laser to interact with the area to be avoided.

[0136] Figure 5 An example of tissue temperature control performed by the device of the present invention is shown. Detailed Implementation

[0137] Figure 1 A general diagram of a biological tissue cutting apparatus for cutting the biological tissue depicted in the figure by means of parallel lines is shown. The apparatus includes a laser emitter (1) configured to cut the tissue in a cutting area (R), the tissue laser emitter (1) being activated and deactivated by a controller (2).

[0138] In one embodiment, the laser emitter (1) includes a scanner that changes the direction of the beam to target different points in an area (R).

[0139] The device also includes an optical module (3) capable of detecting the tissue surface (S) of the region (R). Preferably, the optical module (3) includes an optical system or photoacoustic system that performs a series of measurements and is subsequently processed by a computing device to determine the surface (S) of the tissue.

[0140] In a preferred embodiment, the optical module (3) includes an optical coherence tomography (OCT) system, which may be a polarization-sensitive optical coherence tomography (PS-OCT) system. Other examples of the optical system of the optical module (3) are structured light or stereo pair types. Another example of the photoacoustic system of the optical module (3) is a photoacoustic tomography system.

[0141] In one embodiment, the optical module (3) further includes a light source and a scanner that changes the direction of the light source to align it with different points in the region (R).

[0142] The device also includes a central processing unit (5) that communicates with the controller (2) and the optical module (3). On the one hand, the central processing unit (5) sends instructions to the controller (2) to activate and deactivate the laser. On the other hand, the central processing unit (5) receives information from the optical module (3) and processes it. The central processing unit (5) generates a numerical model (MN) of the region (R), which includes at least the shape of the surface (S) of the region (R) determined by the optical module (3), the direction of the laser beam oriented by the laser emitter (1), and the shape of one or more reference surfaces (SR).

[0143] One or more reference surfaces (SRs) are defined by the processing unit (5) itself. These surfaces (SRs) delineate prohibited areas of tissue that are prohibited from being cut for several reasons (e.g., because the area contains critical tissue such as nerves or blood vessels).

[0144] Furthermore, the central processing unit (5) defines the cutting depth (d) of the laser emitter (1), which can be fixed or varied throughout the surgical intervention. Preferably, the cutting depth (d) can be selected.

[0145] Based on the generated numerical model (MN), the central processing unit (5) estimates the location of a point on the straight line (which represents the laser beam) at a distance equal to the cutting depth (d) from the intersection of the straight line and the surface (S) of the tissue. If the estimated location indicates that the point is outside the restricted area, the central processing unit (5) activates the laser emitter (1) via the controller (2), and conversely, if the point is within the restricted area, the central processing unit deactivates the laser emitter.

[0146] Alternatively or additionally, based on the generated numerical model (MN), the central processing unit (5) estimates the position of a point on the straight line (which represents the laser beam) located from the intersection of the straight line and the surface (S) of the tissue to the intersection plus a distance equal to the cutting depth (d). If the estimated position of the point does not match a point in the prohibited area, the central processing unit (5) activates the laser emitter (1) via the controller (2); conversely, if the position of at least one of the points matches at least one point in the prohibited area, the central processing unit deactivates the laser emitter.

[0147] The central processing unit (5) defines one or more reference surfaces (SRs) based on several criteria.

[0148] Criterion 1: The boundary surface that defines the start or end point of the tissue. The tissue may be the tissue whose surface has been defined by the optical module (3) (i.e., the main tissue) or the tissue adjacent to it.

[0149] Standard 2: Establish a flat surface that is substantially parallel to the focal plane of the laser emitter (1) and / or the focal plane of the optical module (3) to achieve the maximum cutting level.

[0150] Standard 3: Estimate the maximum depth of the surface point by point from the surface (S) of the tissue determined by the optical module (3).

[0151] These reference surfaces (SRs) can be dynamic surfaces, meaning they can change throughout the surgical intervention. For example, a flat surface established at the start of surgery to the maximum cutting level can be updated to a deeper depth as the cutting progresses. In another example, different surfaces with maximum depths can be progressively defined because the surface (S) of the tissue changes gradually throughout the procedure.

[0152] The central processing unit (5) defines these reference surfaces (SRs) based on preoperative information, the measurement results of the optical module (3) itself, and / or decisions made by medical personnel. Once the central processing unit (5) defines the reference surfaces, it assigns these reference surfaces to the generated numerical model (MN).

[0153] Furthermore, to increase safety during the cutting process, the device takes into account the safety margin, which may be fixed or variable throughout the surgical intervention, including the reference surface (SR). Preferably, the central processing unit (5) includes an input device for inputting the safety margin definition, which is entered by medical personnel via an interface.

[0154] Figure 2An exemplary surface (S) of the region (R) defined by the optical module (3) and three reference surfaces (SR1, SR2 and SR3) defined according to three different standards are shown.

[0155] Reference surface SR1 is the surface that demarcates the ends of major tissues, such as the ends of vertebrae in spinal surgery. Figure 2 In this example, the central processing unit (5) defines the surface SR1 and assigns it to the numerical model (MN) based on preoperative images (e.g., images obtained by means of magnetic resonance, computerized axial computed tomography, or fluoroscopy). In an alternative example, the central processing unit (5) defines the surface SR1 and assigns it to the numerical model (MN) based on measurements taken by the optical system or photoacoustic system of the optical module (3).

[0156] Reference surface SR2 is a flat surface with maximum horizontality. Figure 2 In this example, the depth of the reference surface SR2 has been defined by the surgeon at the start of the operation. The depth value determined by the surgeon is received by the central processing unit (5) through an interface, and then the central processing unit (5) processes the information to define the reference surface SR2 and assign the reference surface SR2 to the numerical model (MN).

[0157] The reference surface SR3 is a surface with a maximum depth defined point by point based on the surface (S) of the tissue determined by the optical module (3) at the start of the surgical intervention. The central processing unit (5) receives the surface (S) of the tissue from the optical module (3), processes the information, defines the surface SR3 with the maximum depth, and assigns the surface SR3 to the numerical model (MN).

[0158] Furthermore, the reference surfaces SR2 and SR3 will gradually change throughout the surgical intervention. On one hand, the surgeon will be able to input a new depth value for the new plane SR2 via an interface, and then the central processing unit (5) will process the new depth value of the new flat surface SR2 to define the surface and assign the surface to the numerical model (MN). In addition, considering that the surface (S) of the tissue evolves as the cutting process proceeds, the central processing unit (5) will gradually receive updates about the surface (S) of the tissue from the optical module (3), and then assign the new surface SR3 with the maximum depth to the numerical model (MN), thereby defining the new surface SR3 with the maximum depth.

[0159] in addition, Figure 2A series of points on the tissue (P1, P2, P3, and P4) irradiated by the laser beam are shown. The central processing unit (5) is responsible for determining whether the laser must be activated in each case. To this end, as described above, the central processing unit (5) estimates the position of a point on a straight line (which represents the laser beam) spaced from the intersection of the line and the tissue surface (S) by a distance equal to the cutting depth (d). The point is indicated by a cross in the figure. It should be understood that the point is spaced from the intersection in the opposite direction to the laser beam source, i.e., the pad is located within the tissue. If the estimated position indicates that the point is outside the prohibited area (i.e., the area below one of the reference surfaces (SR1, SR2, and SR3)), the central processing unit (5) activates the laser emitter (1) via the controller (2), and conversely, if the point is within the prohibited area, the central processing unit deactivates the laser emitter.

[0160] Alternatively, the central processing unit (5) estimates the position of a point on a straight line (which represents the laser beam), the point being between the intersection of the straight line and the surface (S) of the tissue and the intersection plus a distance equal to the cutting depth (d). If the estimated position indicates that the entire segment is outside the prohibited area (i.e., the area below one of the reference surfaces (SR1, SR2, and SR3)), the central processing unit (5) activates the laser emitter (1) via the controller (2), and conversely, if the segment is at least partially within the prohibited area, the central processing unit deactivates the laser emitter.

[0161] The following description is in Figure 2 The state of the laser (1) at each of the aforementioned points.

[0162] - Point P1: The laser is activated because this point is located outside all prohibited areas.

[0163] - Point P2: The laser is deactivated because the point is located within the restricted area defined by surface SR2.

[0164] - Point P3: The laser is activated because this point is located outside all prohibited areas.

[0165] - Point P4: The laser is disabled because it is located within the restricted area defined by surface SR1.

[0166] In one example Figure 1 or Figure 2 The central processing unit (5) of any of the devices described in any of the figures is also adapted to continuously scan the light source of the optical module (3) over the region (R).

[0167] The central processing unit (5) controls the scanner to scan the area (R) with the light source of the optical module (3) to perform continuous scanning. As a result, the measurement results and the surface (S) of the tissue are gradually updated in the numerical model (MN).

[0168] In a more specific example, this scan by the light source is performed when outdated criteria for the measurement results selected below are met: -After the pre-established time period has passed - Before the laser emitter (1) is activated or deactivated by the central processing unit (5).

[0169] By applying these outdated standards, the device ensures that the measurements of the optical module (3) will be gradually updated at least every pre-established time period and / or each time the laser changes from a deactivated state to an activated state (and vice versa).

[0170] In one example, the central processing unit (5) is also adapted to perform continuous scanning of a laser beam emitted by the laser emitter (1) over a region (R) until at least one reference surface (SR) is reached. In a particular example, the control of the scan established by the laser emitter (1) and the scan established by the optical module (3) are independent.

[0171] The scan is performed according to a predefined scanning pattern. Preferably, the pattern is uniform. In one example, from the perspective of the surgeon performing the procedure, the pattern is created from the surgeon's left to right and from top to bottom.

[0172] In this process, which is performed in a repetitive and continuous manner, the laser (1) can interact with areas that do not need to be treated (i.e., the restricted areas mentioned above).

[0173] In a preferred example, the central processing unit (5) is further configured such that during the cutting process, when the laser emitter (1) scans a set of points in the region (R), whenever a point sequentially reaches a point where the emission of the laser emitter (1) is blocked, the laser emitter positions itself to the next point where emission is permitted, without stopping the emission of the laser beam.

[0174] In other words, the central processing unit (5) performs control to cause the laser to exclude prohibited areas, thereby completing the process without delay. With the help of the scanner in the optical module (3), the laser can be redirected toward non-prohibited areas.

[0175] In addition to the significant speed achieved by this method, it also demonstrates the advantage that the laser always operates under optimal conditions because the laser is never turned off and therefore never cooled.

[0176] Alternatively, the central processing unit (5) can instruct the laser to continue scanning the predetermined pattern by scanning the prohibited area, but prevent the laser (1) from being activated in that area.

[0177] In a preferred example, the cutting laser gradually scans the biological tissue until the surface is smoothed by the cutting laser. If the surface is smoothed beyond the tolerance range, it is considered that the surface has been successfully smoothed.

[0178] In order to achieve a flat bottom cut, in one embodiment, the central processing unit (5) is also configured to give priority to points with a cut depth less than other points in the scan sequence to compensate for the cut depth.

[0179] Therefore, the central processing unit (5) prioritizes shallower points, deactivating the laser emitter at deeper points or regions and activating it at shallower points or regions. In this way, the surface region becomes increasingly deeper while the deeper regions remain unchanged until all points eventually have the same horizontal position.

[0180] According to another embodiment, in order to maintain the operating conditions of the laser emitter and prevent the laser emitter from cooling down due to inactivity, the laser emitter remains active but jumps between points with higher altitudes, avoiding passing through points with lower altitudes.

[0181] The implementation is, for example Figure 3 As shown, Figure 3 The locations of a set of points on the surface (S) of the tissue irradiated by the laser emitter (1) are shown. In this specific example, a flat reference surface (SR) has been defined, which defines the maximum cutting level to be achieved.

[0182] It can be seen that at point 1, the surface (S) of the tissue has reached the maximum cutting level, while at points P2 to P4, the surface (S) is shallower. In order to achieve a smooth cut, the central processing unit (5) in this example will preferentially cut at point P4, and then cut at points P3 and P2. For safety, this progress and smoothing in tissue cutting is always carried out without violating the defined flat reference surface (SR).

[0183] The flat reference surface (SR) can be progressively established at multiple depth levels with reference to the focal plane of the laser emitter (1) and / or the focal plane of the optical module (3), such that when the entire surface (S) of the tissue descends to the depth of the flat surface due to the laser action of the laser emitter (1), at least one flat surface becomes a deeper depth.

[0184] In one example, any reference surface (SR) can be defined by an input device included in the central processing unit (5) for inputting the definition of at least one reference surface (SR), which is then assigned to the numerical model (MN).

[0185] In another example, the central processing unit (5) includes an input device for inputting a definition of a region to be avoided (RA), the shape of which is assigned to a numerical model (MN). The central processing unit (5) is also configured to deactivate the laser emitter (1) if at least one location in the numerical model (MN) of a point on a line between the intersection of the line and the surface (S) of the tissue and a distance equal to the cutting depth (d) between the intersection coincides with the location of at least one point in the region to be avoided (RA).

[0186] In a specific example, the surgeon selects the area to be avoided (RA) from an image, preferably an RGB video image displayed on a surgical area display device for displaying the surgical area in a planar diagram. In a more specific example, the central processing unit (5) calculates the distance between each point on the surface (S) of the tissue and the reference surface (SR) closest to each point, and displays said distances to the user via the surgical area display device by overlaying the information onto the RGB image. Information about depth is displayed specifically by using a color palette or by depicting the area at different depth levels.

[0187] Both types of input devices can be arranged in the interface that serves as a middleware between the user and the central processing unit (5).

[0188] Figure 4 An example is shown of a reference surface (SR) and a region to be avoided (RA) defined by the surgeon through the input device (specifically the interface) of the central processing unit (5). The central processing unit (5) then assigns the surface and shape of the region to be avoided (RA) to a numerical model (MN).

[0189] In addition, Figure 4 The diagram shows point P on the surface (S) struck by the laser emitter (1) that the central processing unit (5) has ordered to be deactivated. It can be seen that, according to the numerical model (MN), a set of points within a segment defined by the intersection of the straight line representing the laser beam and the surface (S) of the tissue, plus a distance equal to the cutting depth (d), lies within the avoidance zone (RA). Therefore, assuming cutting is prohibited within the avoidance zone (RA), the laser emitter must be deactivated at point P.

[0190] In one example, the central processing unit (5) includes additional security mechanisms to prevent the laser emitter from being activated in dangerous situations.

[0191] On one hand, the central processing unit (5) includes a device for stopping the emission of the laser emitter (1), which is adapted to stop the emission of the laser emitter (1) while it is running. These stopping devices can be used at any time during the operation when medical personnel deem it appropriate.

[0192] In addition, or alternatively, the central processing unit (5) is also configured to deactivate the laser emitter (1) in the numerical model (MN) if the position of any point on the straight line (which represents the laser beam) coincides with the position of a point on the surface (S) of the tissue. This measure attempts to prevent the laser emitter from being activated when it is not well located in the surgical area (R) or when information about the actual surface (S) of the tissue is unavailable (e.g., due to a malfunction in the optical module (3), thus preventing the cutting of critical and non-target tissues. This also constitutes a safety measure in the absence of a patient on the operating table.

[0193] at last, Figure 5 Another safety measure of the device of the present invention is shown: laser power control per unit surface to prevent thermal damage to tissue.

[0194] To this end, the central processing unit (5) is also configured to define a function representing a scalar (X) of a set of points in a region (R) with a specific pattern, wherein: - This function initially uses a pre-established reference value, such as zero; - Whenever the laser emitter (1) hits a point in the pattern, the function adds a first pre-established increment value (ΔX) to that point. - The value of all points is reduced by the second pre-established increment value in each pre-established time period; - For each point in the pattern, if the value of that point exceeds a pre-established threshold (Xth), the point is designated in the numerical model (MN) as a point that is not allowed to be cut as long as the value remains above the threshold (Xth).

[0195] Thus, the device adjusts the laser power per unit surface so that it does not exceed a predetermined threshold (Xth). This threshold (Xth) can be a dynamic threshold or can be gradually changed throughout the surgical intervention. In one example, the user, surgeon, or medical personnel selects the threshold (Xth) at a given time during the surgery and inputs it via an input device in the central processing unit (5), preferably an interface. The pre-established time period can be a fixed or dynamic time period during the surgery. Furthermore, the user or medical personnel who will input this value into the central processing unit (5) via the input device can select this value at a given time during the surgery. In this example, the surgeon selects a fixed time period at the start of the surgery.

[0196] In one example, the apparatus described in any of the accompanying drawings may also include a fluid management unit, not shown in any of the drawings, to provide the apparatus with the ability to clean the surgical area (R). This unit is adapted to provide, in operating mode, the flow of gas, liquid, or a mist of gas containing liquid particles in an area containing a biological tissue region (R) on which the laser emitter (1) acts.

Claims

1. A biological tissue cutting device, comprising: A laser emitter (1) is suitable for cutting biological tissue in a cutting region (R); A controller (2) that communicates with the laser emitter (1) and is adapted to activate and deactivate the laser emitter (1). Optical module (3), the optical module (3) being adapted to determine the surface (S) of the tissue in the region (R) in an operating mode; A central processing unit (5) that communicates with the controller (2) and the optical module (3), the central processing unit (5) being adapted to: The pre-established cutting depth (d) of the laser emitter (1) is defined. Define at least one reference surface (SR); Generate a numerical model (MN) of the region (R), the numerical model (MN) including at least the shape of the surface (S) of the tissue in the region (R), the shape of the at least one reference surface (SR), under which cutting is prohibited, and the direction of the laser beam oriented by the laser emitter (1); as well as If, in the numerical model (MN), a point corresponding to the line representing the laser beam and spaced at a distance equal to the cutting depth (d) from the intersection of the line and the surface (S) of the tissue, is located outside the prohibited region, then the laser emitter (1) is activated, the prohibited region being any part of the tissue in the region (R) where cutting is prohibited.

2. The apparatus according to claim 1, wherein, The central processing unit (5) is further configured to deactivate the laser emitter (1) if, in the numerical model (MN), at least one of the points located between the intersection of the straight line representing the laser beam and the surface (S) of the tissue and the intersection plus a distance equal to the cutting depth (d) coincides with the location of at least one point of the prohibited area.

3. The apparatus according to claim 1, wherein, The central processing unit (5) is further configured to deactivate the laser emitter (1) if, in the numerical model (MN), the position of any point representing the straight line of the laser beam coincides with the position of a point on the surface (S) of the tissue.

4. The apparatus according to claim 1, wherein, The at least one reference surface (SR) is: The boundary surface of the end of the tissue that divides the region (R); or Based on the tissue of the region (R) whose surface has been determined by the optical module (3), the boundary surface of the starting point of different tissues is divided, the different tissues being located at a deeper position than the tissue of the region (R); or Based on the tissue of the region (R) whose surface has been determined by the optical module (3), the boundary surfaces of the ends of different tissues are divided, the different tissues being located at a deeper position than the tissue of the region (R); or Any combination of the aforementioned surfaces.

5. The apparatus according to claim 1, wherein, The at least one reference surface (SR) is a flat surface parallel to the focal plane of the laser emitter (1) and / or the focal plane of the optical module (3).

6. The apparatus according to claim 1, wherein, The at least one reference surface (SR) is a surface having a maximum depth determined from the surface (S) of the tissue.

7. The apparatus according to claim 4, wherein, The at least one reference surface (SR) is: At least one of the boundary surfaces; and / or A flat surface parallel to the focal plane of the laser emitter (1) and / or the focal plane of the optical module (3): and / or A surface having a maximum depth determined from the surface (S) of the tissue.

8. The apparatus according to claim 1, wherein, The central processing unit (5) defines the at least one reference surface (SR) with a safety margin.

9. The apparatus according to claim 1, wherein, The optical module (3) includes an optical coherence tomography (OCT) system.

10. The apparatus according to claim 9, wherein, The optical coherence tomography (OCT) system is a polarization-sensitive optical coherence tomography (PS-OCT) system.

11. The apparatus according to claim 1, wherein, The optical module (3) includes the following systems: Structured light system; or Three-dimensional alignment system; or Photoacoustic tomography system.

12. The apparatus according to claim 1, wherein, The laser emitter (1) includes a scanner that changes the direction of the laser beam to aim the laser beam at different points in the region (R).

13. The apparatus according to claim 1, wherein, The optical module (3) includes a light source and a scanner, the scanner causing the light source to change its direction so that it is aimed at different points in the region (R).

14. The apparatus according to claim 12, wherein, The central processing unit (5) is adapted to perform a continuous scan of the laser beam emitted by the laser emitter (1) on the region (R) until it reaches the at least one reference surface (SR).

15. The apparatus according to claim 13, wherein, The central processing unit (5) is adapted to perform continuous scanning of the light source of the optical module (3) on the region (R).

16. The apparatus according to claim 13, wherein, The control of the scan established by the laser emitter (1) and the scan established by the optical module (3) is independent.

17. The apparatus according to claim 15, wherein, When the following obsolescence criteria are met, a scan of the light source of the optical module (3) is performed in the region (R): After the pre-establishment period has passed Before the laser emitter (1) is activated or deactivated by the central processing unit (5).

18. The apparatus according to claim 5, wherein, In the numerical model (MN) generated by the central processing unit (5), at least one flat surface is progressively established at multiple depth levels with reference to the focal plane of the laser emitter (1) and / or the focal plane of the optical module (3), such that when the surface (S) of the tissue descends to the depth of the flat surface due to the laser action of the laser emitter (1), the at least one flat surface becomes a deeper depth.

19. The apparatus according to claim 1, wherein, The central processing unit (5) includes an input device for inputting the definition of the at least one reference surface (SR) assigned to the numerical model (MN).

20. The apparatus according to claim 19, wherein, The at least one reference surface (SR) is determined by means of preoperative and / or intraoperative images.

21. The apparatus according to claim 20, wherein, The at least one reference surface (SR) is determined by means of magnetic resonance images, computerized axial tomography images, or fluorescence imaging.

22. The apparatus according to claim 20, wherein, The at least one reference surface (SR), determined by means of preoperative and / or intraoperative images, is the boundary surface of the end of the bone tissue that divides the region (R).

23. The apparatus according to claim 1, wherein: The central processing unit (5) includes: an input device for inputting a definition of a region to be avoided (RA), the shape of which is assigned to a numerical model (MN); and The central processing unit (5) is further configured to deactivate the laser emitter (1) if, in the numerical model (MN), at least one of the points located between the intersection of the line representing the laser beam and the surface (S) of the tissue and the intersection plus a distance equal to the cutting depth (d) coincides with the location of at least one point of the area to be avoided (RA).

24. The apparatus according to claim 1, comprising: Surgical area display device.

25. The apparatus according to claim 24, wherein, The surgical area display device is a screen that displays RGB video images.

26. The apparatus according to claim 24, wherein, The surgical area display device also shows information about the distance from each point on the surface (S) of the tissue to the at least one reference surface (SR).

27. The apparatus according to claim 12, wherein, The central processing unit (5) is further configured such that during the cutting process, when the laser emitter (1) scans a set of points in the region (R), whenever a point sequentially reaches a point where the emission of the laser emitter (1) is blocked, the laser emitter positions itself to the next point where emission is permitted, without stopping the emission of the laser beam.

28. The apparatus according to claim 1, wherein, The central processing unit (5) is also configured to define a function representing a scalar (X) of a set of points in the region (R) having a specific pattern, wherein: The function initially uses a pre-established reference value; Whenever the laser emitter (1) hits a point of the pattern, the function adds a first pre-established increment value (ΔX) to that point. The value of all points decreases by the second pre-established increment value during each pre-established time period; For each point in the pattern, if the value of the point exceeds a pre-established threshold (Xth), the point is designated in the numerical model (MN) as a point that is not allowed to be cut as long as the value remains above the threshold (Xth).

29. The apparatus according to claim 12, wherein, The central processing unit (5) is further configured such that, during the cutting process, when the laser emitter (1) scans a set of points in the region (R), priority is given to points with a cutting depth less than other points in the scanning sequence to compensate for the cutting depth.

30. The apparatus according to claim 8, wherein, The central processing unit (5) includes an input device for inputting a definition of the safety margin of the at least one reference surface (SR).

31. The apparatus according to claim 1, wherein, The central processing unit (5) includes a means for stopping the emission of the laser emitter (1), the means being adapted to stop the emission of the laser emitter (1) when the laser emitter (1) is in operation.

32. The apparatus according to claim 1, wherein, The biological tissue cutting device further includes a fluid management unit adapted to provide flow of gas, liquid, or a mist of gas containing liquid particles in the region (R) containing the biological tissue on which the laser emitter (1) acts in the operating mode.

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