Orthopedic surgery robot registration method

Abstract

The invention relates to an orthopedic surgery robot registration method, which comprises the following steps of: setting a to-be-registered area of an affected part according to clinical experience, and performing point sampling on the edge of the to-be-registered area through a mechanical arm probe to form a plurality of reference points; acquiring medical image data of the area and fitting to generate a three-dimensional model containing hard bones, cartilage and surrounding tissues; dividing the to-be-registered region into a plurality of sub-regions according to the image data, and adopting a differential acquisition strategy for different types of regions; planning a collection point coordinate in the three-dimensional model of each sub-region and mapping the collection point coordinate to a mechanical arm probe coordinate system; the pose of the mechanical arm is adjusted through pose planning to ensure that all reference points are within the visual field range of the sensor; the robot carries out plane positioning according to the XY coordinates of the collection points, controls the probe based on the Z-axis parameters to achieve accurate point collection according to different clinical requirements, completes automatic point collection, and improves the surgical precision and efficiency.

Description

Technical Field

[0001] This invention relates to a registration method for orthopedic surgical robots, belonging to the field of orthopedic surgical robot technology. Background Technology

[0002] Currently, orthopedic robotic surgery typically involves preoperative CT and MRI scans of the patient. Based on these data, three-dimensional data of the patient's hard bone, cartilage, and surrounding tissues are fitted. During the surgery, a reference frame is placed in the surgical area for optical positioning. The surgeon holds a probe with a handle and marks points, and takes points on the bone surface (on the cartilage) or punctures the soft tissue to take points on the hard bone as needed. The obtained series of points (with absolute coordinates) are fitted with the preoperative three-dimensional data to obtain the positioning of the patient's bone surface. The host computer then sends the coordinates of the lesion to the robotic arm, and the surgeon pushes and pulls the robotic arm to perform operations such as bone grinding or drilling.

[0003] In the above process, the registration step is extremely demanding on the surgeon's manual skills and experience. For open surgeries (such as knee replacement), the surgeon needs to use a pointed probe to puncture the cartilage (or necrotic tissue) down to the bone surface. This process requires a high level of experience and skill from the surgeon. If the depth of puncture is significantly inaccurate, it will affect the registration accuracy. For minimally invasive surgeries (such as ACL surgery), the surgeon needs to use a blunt probe to take samples on the cartilage surface. Due to the limited field of vision under arthroscopy, the surgeon may apply too much force to the cartilage or fail to contact the cartilage surface, which will also affect the registration accuracy.

[0004] Due to the need for surface fitting of data, doctors need to collect 30-40 points (for surface fitting, adjacent points cannot be too close together), which can easily lead to doctor fatigue, errors, and reduced user experience of the surgical robot. Manual point collection is prone to causing leg movement due to inaccurate force control, so a reference frame must be placed on the patient's leg. The reference frame is prone to becoming invisible at manual data collection points, requiring frequent adjustments to its orientation. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention proposes a registration method for orthopedic surgical robots.

[0006] The technical solution of the present invention is as follows: On one hand, the present invention provides a registration method for an orthopedic surgical robot, comprising the following steps: The pre-defined registration area of ​​the affected area is then sampled using the probe of the orthopedic surgical robot's robotic arm at the edge of the registration area. Collect medical image data of the region to be registered and fit it into a three-dimensional model of the region to be registered; Based on the medical image data of the region to be registered, the region to be registered is divided into multiple regions, and different acquisition strategies are adopted for different types of regions. For any type of region, a corresponding number of acquisition points are planned in the 3D model of the region according to the acquisition strategy, and the coordinates of the acquisition points are set based on the coordinate system of the robotic arm probe. Adjust the posture of the orthopedic surgical robot's robotic arm to ensure that all reference points are within the orthopedic robot's sensors. The orthopedic surgical robot controls the robotic arm to move to the corresponding position based on the XY axis coordinates of each acquisition point. Then, adjust the force value of the robotic arm in the Z-axis direction in real time to control the robotic arm probe to set the acquisition point at that position.

[0007] Preferably, the reference point is obtained by manually controlling a robotic arm probe to puncture the edge of the bone surface.

[0008] Preferably, the medical imaging data of the region to be registered includes MR data and CT data.

[0009] Preferably, the region to be registered is divided into an error region and a non-error region based on the medical image data of the region to be registered; Set the error grayscale range for CT data, identify pixels in the CT data whose grayscale values ​​are within the error grayscale range as error pixels, consider the area formed by error pixels as the error region, and after dividing the error region, the remaining area is considered as the non-error region. Different sampling point densities are set for error regions and non-error regions, and sampling points are planned in the 3D model based on the sampling point density.

[0010] Preferably, the Z-axis control of the robotic arm probe is implemented based on an admittance controller, specifically as follows: According to the surgical requirements, the desired force value of the robotic arm in the Z-axis direction under the robotic arm probe coordinate system is set. During the setting of the acquisition point, the force value of the robotic arm is collected in real time. The robotic arm is driven to move according to the difference between the desired force value and the actual force value of the robotic arm, and the movement speed does not exceed the set speed threshold until the desired force value of the robotic arm is reached, and the acquisition point setting is completed.

[0011] Preferably, the Z-axis control of the robotic arm probe is implemented based on an impedance controller, specifically as follows: Set the expected value of the robotic arm probe on the Z-axis in the coordinate system of the robotic arm probe. The expected value of the Z-axis is calculated based on the reference point. Set the force value of the robotic arm according to the surgical requirements. The robotic arm moves according to the set force value and the expected value of the Z-axis until the robotic arm probe reaches the expected value of the Z-axis, thus completing the setting of the acquisition point.

[0012] On the other hand, the present invention also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method described in the present invention.

[0013] In another aspect, the present invention also provides a computer-readable storage medium having a computer program stored thereon that, when executed by a processor, implements the method described in the present invention.

[0014] The present invention has the following beneficial effects: 1. This invention integrates a force sensor at the end of a robotic arm and employs admittance control or impedance control strategies, enabling the robotic arm to automatically identify the contact state between the probe and the bone surface based on a preset desired force value; this avoids the registration point offset problem caused by human error and improves the positioning accuracy and intraoperative navigation reliability of the surgical robot. Attached Figure Description

[0015] Figure 1 This is a flowchart of the method of the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0017] It should be understood that the step numbers used in the text are for ease of description only and are not intended to limit the order in which the steps are performed.

[0018] It should be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0019] The terms “comprising” and “including” indicate the presence of the described feature, whole, step, operation, element and / or component, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0020] The term “and / or” refers to any combination of one or more of the associated listed items, as well as all possible combinations, and includes these combinations.

[0021] See Figure 1 In some embodiments, a registration method for orthopedic surgical robots is proposed, comprising the following steps: Based on the medical image data of the region to be registered, the region to be registered is divided into multiple regions, and different acquisition strategies are adopted for different types of regions. Medical imaging data of the region to be registered are collected and fitted into a three-dimensional model of the hard bone, cartilage and surrounding tissues of the region to be registered. Based on the medical image data of the region to be registered, the region to be registered is divided into multiple regions, and different acquisition strategies are adopted for different types of regions. For any type of region, a corresponding number of acquisition points are planned in the 3D model of the region according to the acquisition strategy, and the coordinates of the acquisition points are set based on the coordinate system of the robotic arm probe. Adjust the posture of the orthopedic surgical robot's robotic arm to ensure that all reference points are within the orthopedic robot's sensors (such as infrared sensors). The orthopedic surgical robot controls the robotic arm to move to the corresponding position based on the XY axis coordinates of each acquisition point. Then, adjust the force value of the robotic arm in the Z-axis direction in real time to control the robotic arm probe to set the acquisition point at that position.

[0022] In some embodiments, the reference point is specifically marked by manually controlling a robotic arm probe to puncture the edge of the bone surface. There are no requirements for positional accuracy. Depending on clinical requirements, the cartilage is punctured if necessary, and the cartilage surface is touched if necessary.

[0023] In some embodiments, the medical imaging data of the region to be registered includes MR data and CT data.

[0024] In some embodiments, the region to be registered is divided into an error region and a non-error region based on the medical image data of the region to be registered; Set the error grayscale range for CT data, identify pixels in the CT data whose grayscale values ​​are within the error grayscale range as error pixels, consider the area formed by error pixels as the error region, and after dividing the error region, the remaining area is considered as the non-error region. Different sampling point densities are set for error regions and non-error regions, and sampling points are planned in the 3D model based on the sampling point density.

[0025] In one specific embodiment, the error grayscale range is 250 to 450.

[0026] In one specific embodiment, the sampling point density in the error region is two sampling points per square centimeter; The sampling point density in the non-error region is one sampling point per square centimeter.

[0027] In some embodiments, the Z-axis control of the robotic arm probe is implemented based on an admittance controller, specifically as follows: According to the surgical requirements, the desired force value of the robotic arm in the Z-axis direction under the robotic arm probe coordinate system is set. During the setting of the acquisition point, the force value of the robotic arm is collected in real time. The robotic arm is driven to move according to the difference between the desired force value and the actual force value of the robotic arm, and the movement speed does not exceed the set speed threshold until the desired force value of the robotic arm is reached, and the acquisition point setting is completed.

[0028] In some embodiments, the Z-axis control of the robotic arm probe is implemented based on an impedance controller, specifically as follows: Set the expected value of the robotic arm probe on the Z-axis in the coordinate system of the robotic arm probe, ensuring that this expected value is within the bone (i.e., under the cartilage or under the bone). The expected value of the Z-axis is calculated based on the reference point. Set the robotic arm force value according to the surgical requirements. The robotic arm moves according to the set force value and the expected value of the Z-axis until the robotic arm probe reaches the expected value of the Z-axis, thus completing the acquisition point setting.

[0029] In one specific embodiment, a flexible mechanism (such as a spring) is installed between the end flange and the probe of the robotic arm. According to prior tests, the hard bone is one type of flexible mechanism and the soft bone is another type of flexible mechanism, ensuring that the robotic arm exhibits a certain degree of flexibility to meet the different contact bone surface requirements.

[0030] In one specific embodiment, during the acquisition process, the force values ​​in the XYZ directions are monitored in real time to ensure that the force does not exceed a set threshold and the rate of change of force does not exceed a set threshold, thus ensuring that the patient's leg does not shift during the acquisition process, thereby eliminating the need for a reference frame.

[0031] In some embodiments, an electronic device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method as described in any embodiment of the present invention.

[0032] In some embodiments, a computer-readable storage medium is provided on which a computer program is stored, which, when executed by a processor, implements the method as described in any embodiment of the present invention.

[0033] In this application embodiment, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent the existence of A alone, A and B simultaneously, or B alone. A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" and similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, at least one of a, b, and c can represent: a, b, c, a and b, a and c, b and c, or a and b and c, where a, b, and c can be single or multiple.

[0034] Those skilled in the art will recognize that the units and algorithm steps described in the embodiments disclosed herein can be implemented using electronic hardware, computer software, or a combination of electronic hardware and software. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0035] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0036] In the several embodiments provided in this application, any function, if implemented as a software functional unit and sold or used as an independent product, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0037] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. An orthopedic surgical robot registration method, comprising: The method comprises the following steps: presetting a registration area of a lesion, and collecting a plurality of reference points on the edge of the registration area by a mechanical arm probe of an orthopedic surgery robot; collecting medical image data of the registration area and fitting the medical image data into a three-dimensional model of the registration area; dividing the registration area into a plurality of regions based on the medical image data of the registration area, and adopting different collection strategies for different types of regions; for any type of region, planning a corresponding number of collection points in the three-dimensional model of the region by the collection strategy, and setting the coordinates of the collection points based on a mechanical arm probe coordinate system; adjusting the posture of the mechanical arm of the orthopedic surgery robot to ensure that all the reference points are within the sensor of the orthopedic robot, and controlling the mechanical arm to move to the corresponding position according to the XY axis coordinates of each collection point, and then adjusting the force value of the Z axis of the mechanical arm in real time to control the mechanical arm probe to collect the points at the position.

2. The registration method of claim 1, wherein, The reference point collection is specifically manually controlling the mechanical arm probe to punch to the edge of the bone surface.

3. The registration method of orthopedic surgery robot according to claim 1, wherein, The medical image data of the registration area comprises MR data and CT data.

4. The registration method of claim 3, wherein, The registration area is divided into an error region and a non-error region based on the medical image data of the registration area; setting an error gray scale range of the CT data, determining the pixel points with the gray scale values in the error gray scale range in the CT data as error pixel points, regarding the region composed of the error pixel points as the error region, and regarding the remaining region as the non-error region after the error region is divided; setting different collection point densities for the error region and the non-error region, and planning the collection points in the three-dimensional model based on the collection point densities.

5. The registration method of orthopedic surgery robot according to claim 1, wherein, The Z axis control of the mechanical arm probe is realized based on a mobility controller, and specifically comprises the following steps: setting an expected force value of the mechanical arm in the Z axis direction in the mechanical arm probe coordinate system according to the surgical requirements, collecting the force value of the mechanical arm in real time during the setting of the collection point, driving the mechanical arm to move according to the difference between the expected force value of the mechanical arm and the actual force value of the mechanical arm, and the movement speed does not exceed a set speed threshold until the expected force value of the mechanical arm is reached, and the setting of the collection point is completed.

6. The registration method of orthopedic surgery robot according to claim 1, wherein, The Z axis control of the mechanical arm probe is realized based on an impedance controller, and specifically comprises the following steps: setting an expected value of the mechanical arm probe in the Z axis according to the reference point, setting a force value of the mechanical arm according to the surgical requirements, and driving the mechanical arm to move according to the set force value and the expected value of the Z axis until the mechanical arm probe reaches the expected value of the Z axis, and the setting of the collection point is completed.

7. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor executes the program to realize the method of any one of claims 1 to 6.

8. A computer-readable storage medium having stored thereon a computer program, characterized in that, The program is executed by the processor to realize the method of any one of claims 1 to 6.

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