Robot-assisted cranio-maxillofacial osteotomy method and internal fixation plate designing and shaping system

Abstract

The invention provides a robot-assisted cranio-maxillofacial osteotomy method and an internal fixation plate designing and shaping system.The internal fixation plate designing system comprises an osteotomy data obtaining module, an internal fixation plate designing module and an internal fixation plate simulating module; wherein the osteotomy data acquisition module is composed of an image processing sub-module, an image interaction sub-module and a first model import module; the internal fixing plate shaping system is composed of a second model import module, a station conversion module, a laser cutting module, a 3D printing module, a detection module and a polishing module. And the internal fixed plate design module is connected with the internal fixed plate design system output module. Preoperative virtual design and intraoperative physical operation real-time navigation feedback are adopted, after the fixing plate is manufactured, closed loop correction errors are conducted through digital inspection, the material and the structure of the fixing plate are dynamically optimized according to the bone segment load, and the problems that an existing oral cranio-maxillofacial fixing plate technology is low in precision, poor in adjustment efficiency and lack of mechanical verification are solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oral and maxillofacial devices, in particular to a robot-assisted maxillofacial osteotomy method and an internal fixation plate design and shaping system. BACKGROUND

[0002] Oral and maxillofacial osteotomy surgery is a key technology for correcting jaw deformities, repairing trauma, or improving facial appearance. During the surgery, the surgeon needs to mark the osteotomy line on the bone according to the preoperative planning, move the free bone segment to the target position after cutting the bone, and use a fixation plate (such as a titanium plate or a 3D printed bone plate) to fix it to achieve accurate reconstruction of the bone and restore the patient's facial appearance and occlusion function.

[0003] The existing technical process has the following technical defects:

[0004] 1) The surgical procedure relies on experience, has insufficient accuracy, is difficult, and takes a long time:

[0005] The planned osteotomy line is marked on the bone surface by the surgeon during the operation, and the accuracy of the osteotomy line is poor, and the vector direction of the osteotomy surface cannot be reproduced, making it difficult to perform accurate osteotomy; the six-degree-of-freedom (translation and rotation) positioning of the bone segment after osteotomy lacks quantitative standards, which can easily lead to postoperative errors (such as displacement deviation of more than 1 mm, which can cause occlusion disorder or facial asymmetry); in traditional surgery, osteotomy line planning and fixation plate design mainly rely on the experience of the surgeon, and the osteotomy is performed manually, the free bone segment is positioned, and the shape of the fixation plate needs to be adjusted through repeated trial and error, such as manually bending the titanium plate;

[0006] The existing fixation plate technology has the following technical defects:

[0007] A. Pre-made titanium plate:

[0008] The titanium plate shape needs to be adjusted manually during the operation, which is time-consuming and has low accuracy (bending error can reach ±0.5 mm), resulting in poor fit of the titanium plate to the bone surface, increasing the risk of delayed bone healing; the titanium plate adjustment process prolongs the operation time (about 20-30 minutes per block), increasing the risk of infection; manual bending of the titanium plate shape causes stress release in the titanium plate, affecting the accuracy and stability of postoperative fixation; the manual bending process can damage the smoothness of the titanium plate surface, forming bacterial biofilm and increasing the risk of postoperative infection;

[0009] B. In orthognathic surgery, 3D printed bone plates can achieve personalized matching, but still have the following technical defects, which directly affect the surgical outcome and patient prognosis:

[0010] 1) Accuracy and matching problems:

[0011] Model conversion error: During the conversion from patient CT data to 3D printed model, the gap between the bone plate and the bone surface may be ≥0.2mm due to image segmentation algorithm bias (e.g. blurred bone boundary) or printing layer thickness limitation (typical layer thickness 50-100μm), affecting initial stability; Case: Clinical studies show that the edge matching error rate of 3D printed bone plates reaches 12% (data source: Journal of Cranio-Maxillofacial Surgery), which requires manual adjustment during surgery;

[0012] Size distortion caused by thermal deformation: High molecular materials (such as PEEK) may warp and deform during printing due to cooling shrinkage or thermal stress release, causing bone plate hole position deviation (typical error ±0.3mm), which does not match the preoperative plan;

[0013] 2) Production cycle and intraoperative adjustment limitations:

[0014] Long production cycle: From data acquisition to printing completion, it takes 48-72 hours, and if the bone plate error is found during surgery (such as osteotomy position adjustment), re-printing requires secondary sterilization and waiting, which prolongs the operation time by 2-3 hours and increases the risk of infection;

[0015] Irreversible modification during surgery: Most existing 3D printed bone plates are of integral structure, and if adjustment is needed during surgery, it can only be achieved by cutting or bonding: cutting will damage the internal support structure (such as honeycomb weight reduction design), resulting in a decrease in strength of more than 40%; bonding materials (such as bone cement) may cause foreign body reaction or pollution risk;

[0016] Insufficient control of surface roughness: If the surface roughness (Ra value) of the 3D printed bone plate exceeds 1.6μm, it is easy to form bacterial biofilm, which increases the probability of postoperative infection (rough surface infection rate is 2.3 times higher than polished surface);

[0017] 3) Lack of systematic verification closed loop:

[0018] Existing technology does not form a closed loop of fixed plate design, production and inspection:

[0019] The design stage ignores mechanical analysis (such as not simulating the deformation of the fixed plate under occlusal force load);

[0020] After production, there is no comparison between the actual object and the design model through high-precision scanning (such as ±0.02mm optical scanning), resulting in size out-of-tolerance (≥0.1mm) of the fixed plate flowing into the surgery;

[0021] The above defects may cause insufficient strength of the fixed plate (such as titanium plate yield strength less than 500MPa, which is prone to breakage) or poor fit, requiring secondary surgery to correct, increasing the risk to patients;

[0022] The existing oral craniomaxillofacial fixation plate technology has three core problems of low precision (manual operation error), poor adjustment efficiency (intraoperative time consumption), and lack of mechanical verification (insufficient strength), which are caused by the following reasons: disconnection between planning and execution: lack of real-time feedback between preoperative virtual design and intraoperative physical operation; separation between manufacturing and testing: the fixation plate is not corrected after being made through digital testing; and mismatch between material and mechanical properties: the fixation plate material and structure are not dynamically optimized according to the bone segment load.

[0023] Therefore, how to design a robot-assisted craniomaxillofacial osteotomy method and how to design a robot-assisted craniomaxillofacial osteotomy internal fixation plate design and shaping system have become urgent problems to be solved. SUMMARY

[0024] In view of the problems in the prior art, the present application provides a robot-assisted craniomaxillofacial osteotomy method and an internal fixation plate design and shaping system to solve at least one of the above technical problems.

[0025] The technical solution of the present application is: a robot-assisted craniomaxillofacial osteotomy method, comprising the following steps:

[0026] S1. The internal fixation plate material design system output module includes the three-dimensional pose of the osteotomy line and the osteotomy surface, the final target pose of the free bone segment, the bone hole pose of the non-free bone segment, and the patient three-dimensional model, the patient in the physical space, and the robot are registered through the coordinate registration module. The coordinate registration module is any one of infrared binocular vision or 3D structured light; the robot is a six-axis or seven-axis serial collaborative arm, and the six-axis or seven-axis serial collaborative arm has force feedback function;

[0027] S2. Convert the three-dimensional pose of the osteotomy line and the osteotomy surface, the bone hole pose of the non-free bone segment, and the surgical execution bone hole pose of the free bone segment into the robot space pose; convert the patient in the physical space to the robot coordinate system;

[0028] S3. The robot and the osteotomy tool arranged at the end thereof, including a micro drill and a reciprocating saw, perform drilling of the fixation hole according to the bone hole pose of the non-free bone segment and the surgical execution bone hole pose of the free bone segment;

[0029] S4. After drilling is completed, the robot and the osteotomy tool arranged at the end thereof, including a micro drill and a reciprocating saw, perform osteotomy according to the three-dimensional pose of the osteotomy line and the osteotomy surface;

[0030] S5. Finally, the fixation holes of the internal fixation plate are aligned with the non-free bone segments and are locked with screws in sequence, and the fixation holes on the cut free bone segments are aligned with the fixation holes on the internal fixation plate and are locked in sequence.

[0031] The application adopts a robot-assisted craniofacial osteotomy method, through preoperative virtual design and intraoperative physical operation real-time navigation feedback, after the fixing plate is made, the error is corrected through digital inspection closed loop, the fixing plate material and structure are dynamically optimized according to the bone segment load, the problems of low precision (manual operation error), poor adjustment efficiency (intraoperative time consumption), and mechanical verification missing (insufficient strength) existing in the existing oral craniofacial fixing plate technology are solved, when the robot drills and cuts the bone, the doctor drags the robot to operate under the condition of the robot constraint pose, the operation difficulty is reduced, and accurate osteotomy can be performed.

[0032] The technical scheme of the application is: a robot-assisted craniofacial osteotomy internal fixation plate material design and shaping system, comprising an internal fixation plate material design system and an internal fixation plate material shaping system, the internal fixation plate material design system comprises an osteotomy data acquisition module, an internal fixation plate material design module and an internal fixation plate material simulation module, wherein the osteotomy data acquisition module is composed of an image processing submodule, an image interaction submodule and a first model import module; the internal fixation plate material shaping system is composed of a second model import module, a station conversion module, a laser cutting module, a 3D printing module, a detection module and a polishing module; the internal fixation plate material design module is connected with an internal fixation plate material design system output module; the image processing submodule acquires and visualizes the digital information of a patient, such as point cloud data of a transverse plane, a sagittal plane and a coronal plane, by loading DICOM image data of the patient, such as CT, MR and QCT; the multi-modal image data of the patient is registered and fused; the three-dimensional model of the patient is reconstructed according to the setting of the image interaction submodule; and the model is reconstructed according to the three-dimensional point cloud file imported by the first model import module.

[0033] The osteotomy data acquisition module of the application loads the DICOM image data of the patient by using the image processing submodule, acquires and generates point cloud data, reconstructs the three-dimensional model of the patient by using the image interaction submodule, and reconstructs the model by using the three-dimensional point cloud file imported by the first model import module, so that the osteotomy data can be collected before the operation and used in virtual design.

[0034] Preferably, the image interaction submodule comprises a parameter setting module, which is used for setting the parameters of three-dimensional reconstruction, including an isosurface and an HU value, and can adjust the effect of three-dimensional reconstruction; the starting point and the ending point of the osteotomy line are set by selecting the point cloud data based on the interactive peripheral device, the osteotomy line is single or multiple; the osteotomy surface is set based on the edge of the osteotomy line, and the osteotomy surface is single or multiple; the size and the vector direction of the osteotomy surface can be adjusted based on the osteotomy line; after the single or multiple osteotomy surfaces are combined, the point cloud data is divided into different combinations, one or more point cloud data combinations can be selected as the free bone segment; the three-dimensional pose of one or more free bone segments is defined in the three-dimensional model of the patient according to the orthodontic needs, so that the three-dimensional model of the patient including the three-dimensional pose of the osteotomy line and the osteotomy surface and the final target pose of the free bone segment is planned and obtained.

[0035] The application adopts the image interaction sub-module to adjust the effect of three-dimensional reconstruction, plans and obtains a three-dimensional model of a patient including three-dimensional positions and poses of osteotomy lines and osteotomy surfaces and a final target position of a free bone segment, and is convenient to use in virtual design. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 It is a schematic structural diagram of the internal fixation plate material design and shaping system module of the application. DETAILED DESCRIPTION

[0037] The application will be further described below with reference to the drawings.

[0038] Referring to Figure 1 The structures, proportions, sizes, etc. shown in the drawings attached to the present specification are only used to cooperate with the content disclosed in the specification, to be understood and read by those skilled in the art, and do not have technical substantive significance, so any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effect and purpose that can be achieved by the application, should still fall within the scope covered by the disclosed technical content. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and "one" used in the present specification are only for the convenience of clear understanding of the description, and are not used to limit the scope of the application, and the change or adjustment of the relative relationship, without substantially changing the technical content, is also considered as the implementation scope of the application.

[0039] Example one, a robot-assisted craniofacial osteotomy method, comprising the following steps:

[0040] S1. The internal fixation plate material design system output module includes a three-dimensional model of a patient including three-dimensional positions and poses of osteotomy lines and osteotomy surfaces, a final target position of a free bone segment, a non-free bone segment drill hole position, and a free bone segment surgical execution drill hole position; a patient in a physical space; and a robot, which are registered by a coordinate registration module. The coordinate registration module is any one of infrared binocular vision or 3D structured light. The robot is a six-axis or seven-axis serial collaborative arm, which has a force feedback function;

[0041] S2. Convert the three-dimensional positions and poses of the osteotomy lines and osteotomy surfaces, the non-free bone segment drill hole position, and the free bone segment surgical execution drill hole position into robot space positions; and convert the patient in the physical space into the robot coordinate system;

[0042] S3. A robot and an osteotomy tool provided at the end thereof, including a micro drill and a reciprocating saw, perform drill hole fixation according to the non-free bone segment drill hole position and the free bone segment surgical execution drill hole position;

[0043] S4. After the drilling is completed, the robot and the osteotomy tool arranged at the end thereof, including a micro drill and a reciprocating saw, perform osteotomy according to the three-dimensional pose of the osteotomy line and the osteotomy surface;

[0044] S5. Finally, the fixing holes of the internal fixation plate are aligned with the non-free bone segments and are locked with screws in sequence, and the fixing holes on the cut free bone segments are aligned with the fixing holes on the internal fixation plate and are locked in sequence. The robot-assisted craniofacial osteotomy method adopted in the application solves the problems of low precision (manual operation error), poor adjustment efficiency (intraoperative time consumption), and lack of mechanical verification (insufficient strength) existing in the current oral craniofacial fixation plate technology through preoperative virtual design and intraoperative physical operation real-time navigation feedback, digital inspection closed-loop correction of errors after the fixation plate is made, and dynamic optimization of fixation plate material and structure according to bone segment load. When the robot performs drilling and osteotomy, the doctor drags the robot to operate under the condition of robot constraint pose, which reduces the operation difficulty and enables accurate osteotomy.

[0045] Embodiment two, a robot-assisted craniofacial osteotomy internal fixation plate material design and shaping system, referring to Figure 1 , comprising an internal fixation plate material design system and an internal fixation plate material shaping system, the internal fixation plate material design system comprises an osteotomy data acquisition module, an internal fixation plate material design module and an internal fixation plate material simulation module, wherein the osteotomy data acquisition module is composed of an image processing submodule, an image interaction submodule and a first model import module; the internal fixation plate material shaping system is composed of a second model import module, a station conversion module, a laser cutting module, a 3D printing module, a detection module and a polishing module; the internal fixation plate material design module is connected with the internal fixation plate material design system output module; the image processing submodule acquires and visualizes the digital information (point cloud data) of the patient, such as transverse, sagittal and coronal planes, by loading the DICOM image data (such as CT, MR and QCT) of the patient; the multi-modal image data of the patient is registered and fused; the three-dimensional model of the patient is reconstructed according to the setting of the image interaction submodule; and the model is reconstructed according to the three-dimensional point cloud file imported by the first model import module. The osteotomy data acquisition module of the application loads the DICOM image data of the patient by using the image processing submodule, acquires and generates point cloud data, reconstructs the three-dimensional model of the patient by using the image interaction submodule, and reconstructs the model by using the three-dimensional point cloud file imported by the first model import module, so as to realize the collection of osteotomy data before operation and facilitate the use in virtual design.

[0046] Example three, on the basis of example two, the image interaction sub-module can set the parameters of three-dimensional reconstruction, such as: isosurface, HU value, which is adjusted by the doctor according to the need to adjust the effect of three-dimensional reconstruction; through the obtained digital information (point cloud data) of the patient, based on the interactive peripherals such as: mouse, point cloud data is set to set the starting point and the end point of the osteotomy line, and the osteotomy line is single or multiple; based on the osteotomy line, the osteotomy surface is set as an edge, and the osteotomy surface is single or multiple; the size and vector direction of the osteotomy surface can be adjusted based on the osteotomy line; when the single or multiple osteotomy surfaces are combined, the point cloud data is divided into different combinations, and one or more point cloud data combinations can be selected as the free bone segment; the three-dimensional pose of one or more free bone segments is defined by the doctor according to the need of orthognathism in the three-dimensional model of the patient, so as to plan and obtain the three-dimensional model of the patient including the three-dimensional pose of the osteotomy line and the osteotomy surface and the final target pose of the free bone segment. The image interaction sub-module is used to adjust the effect of three-dimensional reconstruction, plan and obtain the three-dimensional model of the patient including the three-dimensional pose of the osteotomy line and the osteotomy surface and the final target pose of the free bone segment, which is convenient for use in virtual design.

[0047] Example four, on the basis of example three, the first model import module is used to import a three-dimensional point cloud file such as: an STL format file, and the STL format file is an intermediate bite plate, a final bite plate, a free bone segment, etc. of a patient who is unmolded or digitized scanned; the imported STL format file is three-dimensionally reconstructed into an STL model by the image processing sub-module; the STL model and the reconstructed three-dimensional model of the patient are registered by coordinate matching and displayed in the three-dimensional model of the patient; when the imported model is used for the free bone segment, the osteotomy line, the osteotomy surface and the free bone segment are set in the three-dimensional model of the patient based on the patient point cloud data covered by the registered STL model by the doctor; the three-dimensional pose of the set free bone segment is set in the three-dimensional model of the patient by the image interaction sub-module; when the imported model is used for the intermediate bite plate or the final bite plate, the three-dimensional pose of the free bone segment is adjusted in the three-dimensional model of the patient by the doctor so that the free bone segment matches the intermediate bite plate or the final bite plate, so as to plan and obtain the three-dimensional model of the patient including the three-dimensional pose of the osteotomy line and the osteotomy surface and the final target pose of the free bone segment. The first model import module is used to import a three-dimensional point cloud file, and the three-dimensional pose of the free bone segment is adjusted in the three-dimensional model of the patient so that the free bone segment matches the intermediate bite plate or the final bite plate, which is convenient for use in virtual design.

[0048] Example five, on the basis of example four, the internal fixation plate material library presets a plurality of shapes of the internal fixation plate material, such as a one-letter type, a T type, an I type, an L type, a Y type, etc.; the internal fixation plate material library presets a plurality of thicknesses of the internal fixation plate material, such as 0.5mm, 0.7mm, 1mm, 1.2mm, 1.5mm, etc.; the internal fixation plate material library presets a plurality of materials of the internal fixation plate material, such as titanium alloy, PLA, PEEK, PGA, etc.; the internal fixation plate material library presets a plurality of mechanical parameters of the internal fixation plate material, such as elastic modulus, Poisson's ratio, yield strength, tensile strength, plastic hardening, etc.; the design interaction submodule obtains the three-dimensional model of the patient including the three-dimensional pose of the osteotomy line and the osteotomy surface and the final target pose of the free bone segment through the osteotomy data acquisition module; the doctor frames the fixed region on the three-dimensional model of the patient planned in the osteotomy data acquisition module according to the fixing needs; the doctor selects the thickness and material of the fixed plate according to the fixing needs; the internal fixation plate material library data is called according to the shape and size of the framed fixed region and the bone surface curvature, and the position, shape, size of the internal fixation plate are preliminarily generated; or when the image processing submodule is loaded with QCT data, the doctor frames the fixed region on the three-dimensional model of the patient planned in the osteotomy data acquisition module according to the fixing needs; the doctor selects to automatically generate the internal fixation plate, and the module automatically generates the position, shape, size, material, thickness of the internal fixation plate based on the QCT data, the bone surface curvature and the shape and size of the fixed region. The present application sets the thickness, material, position, shape, size, etc. of the internal fixation plate in the internal fixation plate material library, and realizes the virtual design of the internal fixation plate.

[0049] Example six, on the basis of example five, the mechanical analysis module, the doctor sets the load and boundary conditions, such as: define the load type (static occlusal force 300N, dynamic cyclic load 50-500N@2Hz), the both ends of the bone plate are fixed (simulating screw constraint) and the like. The mechanical analysis module carries out stress finite element analysis of the internal fixation plate according to the patient's three-dimensional model including the three-dimensional pose of the osteotomy line and the osteotomy surface and the final target pose of the free bone segment and the position, shape, size, material, thickness of the internal fixation plate; the stress finite element analysis outputs stress nephogram, displacement field, strain energy density distribution and the like, and gives improvement suggestions (such as "it is suggested to increase the plate thickness to 1.5mm to reduce stress concentration"); the doctor can modify the parameters of the internal fixation plate in the design interaction sub-module according to the stress finite element analysis results and repeat the stress analysis until the results meet the requirements; when the results meet the requirements, the doctor can select to generate the internal fixation plate, which will automatically generate the fixation hole of the internal fixation plate and the fixation hole of the bone according to the simulation results. The fixation hole of the bone is added in the three-dimensional model of the patient in the form of three-dimensional pose; the fixation hole of the bone is divided into the fixation hole on the free bone segment and the fixation hole on the non-free bone segment; the fixation hole on the free bone segment is recalculated according to the moving pose relationship of the free bone segment relative to the non-free bone segment. The mechanical analysis model is based on the API of open source library such as CalculiX, Code_Aster or commercial software such as ANSYS. The present application adopts the mechanical analysis module to carry out mechanical analysis and verification on the virtually designed internal fixation plate, and modifies according to the simulation results until the fixation hole of the internal fixation plate and the fixation hole of the bone are generated, solving the problem of lack of mechanical verification (insufficient strength) in the existing oral and maxillofacial fixation plate technology.

[0050] Example seven, on the basis of example five, the internal fixation plate material design system output module includes the three-dimensional pose of the osteotomy line and the osteotomy surface and the final target pose of the free bone segment, the non-free bone segment drill hole pose, the patient's three-dimensional model of the free bone segment surgery execution drill hole pose, the internal fixation plate STL file including shape, size, thickness, material. The present application adopts the internal fixation plate material design system output module to output the patient's three-dimensional model and the internal fixation plate STL file to the internal fixation plate material shaping system, solving the problem of poor adjustment efficiency (intraoperative time consumption) in the existing oral and maxillofacial fixation plate technology.

[0051] Example eight, on the basis of example seven, the second model import module is used to import the STL file of the internal fixation plate; based on different 3D printing material printing process, error and material characteristics, in order to avoid the possible warping deformation caused by cooling shrinkage or thermal stress release, the second model import module sets the external expansion area of the internal fixation plate 3D printing according to the material of the imported STL file and the shape and size of the internal fixation plate; the 3D printing external expansion area is different in range based on the difference of different material 3D printing process and error; the printing thickness of the 3D printing external expansion area is different based on the difference of different material 3D printing process and error; the 3D printing module prints the primary internal fixation plate according to the imported STL file of the internal fixation plate and the set external expansion area. The STL file of the internal fixation plate designed by the internal fixation plate material design system is imported by the second model import module, the external expansion area of the 3D printing of the internal fixation plate is set, the 3D printing module prints the primary internal fixation plate, and the problem of poor adjustment efficiency (time-consuming in operation) existing in the existing oral craniomaxillofacial fixation plate technology is solved.

[0052] Example nine, on the basis of example eight, the station changing module is composed of XYZ motion platform and clamp arranged thereon, after the primary internal fixation plate is 3D printed and completely cooled, the primary internal fixation plate is sent to the detection station of the detection module by the station changing module; the detection module is composed of three-dimensional surface optical scanning device and image processing module; the three-dimensional surface optical scanning device is used to acquire the surface point cloud data of the 3D printed internal fixation plate; the image processing module performs coordinate registration and fusion on the acquired surface point cloud data of the 3D printed internal fixation plate and the imported STL data, and compares the difference with the imported STL data. When the surface compliance of the primary internal fixation plate meets the standard compared with the imported STL data by the image processing module, the station changing module sends the primary internal fixation plate to the cutting station of the laser cutting module. The 3D printed primary internal fixation plate is sent to the detection station of the detection module by the station changing module, the real object is compared with the design model by high-precision optical scanning, the size out-of-tolerance is avoided, when the surface compliance of the primary internal fixation plate meets the standard compared with the imported STL data by the image processing module, the station changing module sends the primary internal fixation plate to the cutting station of the laser cutting module, the laser cutting of the primary internal fixation plate is realized, and the problems of low precision (manual operation error) and poor adjustment efficiency (time-consuming in operation) existing in the existing oral craniomaxillofacial fixation plate technology are solved.

[0053] In the embodiment ten, on the basis of the embodiment nine, the laser cutting module will cut and open the fixed hole of the primary internal fixation plate according to the registration fusion result of the acquired surface point cloud data of the primary internal fixation plate and the imported STL data, and obtain the secondary internal fixation plate according to the imported STL data; when the secondary internal fixation plate is cut, the work position changing module sends the secondary internal fixation plate to the detection work position of the detection module, the image processing module performs coordinate registration and fusion on the acquired surface point cloud data of the 3D printed internal fixation plate and the imported STL data, and compares the difference with the imported STL data; the image processing module compares the surface compliance of the secondary internal fixation plate with the imported STL data, and the internal fixation plate shaping is completed when the surface compliance meets the standard; the work position changing module, the laser cutting module and the detection module have a coordinate calibration relationship; after the internal fixation plate shaping is completed, the work position changing module sends the internal fixation plate to the polishing module for polishing; the polishing module adopts the magnetic fluid polishing technology. The laser cutting module is used to cut and open the fixed hole of the primary internal fixation plate to obtain the secondary internal fixation plate, the work position changing module sends the secondary internal fixation plate to the detection work position of the detection module when the secondary internal fixation plate is cut, the image processing module compares the surface compliance of the secondary internal fixation plate with the imported STL data, and the internal fixation plate shaping is completed when the surface compliance meets the standard, and the polishing module is used for polishing, the magnetic fluid polishing technology can polish the internal fixation plate to the maximum extent and reduce the deformation caused by polishing, and the problems of low precision (manual operation error) and poor adjustment efficiency (intraoperative time consumption) of the existing oral craniomaxillofacial fixation plate technology are solved.

[0054] The above is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, a number of improvements and refinements can be made, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A robot-assisted craniofacial osteotomy internal fixation plate design and shaping system, comprising an internal fixation plate design system and an internal fixation plate shaping system, characterized in that: The internal fixation plate design system includes an osteotomy data acquisition module, an internal fixation plate design module, and an internal fixation plate simulation module. The osteotomy data acquisition module consists of an image processing submodule, an image interaction submodule, and a first model import module. The internal fixation plate shaping system consists of a second model import module, a workstation transformation module, a laser cutting module, a 3D printing module, a detection module, and a polishing module. The internal fixation plate design module is connected to the output module of the internal fixation plate design system. The image processing submodule loads the patient's DICOM image data, such as CT, MR, and QCT, to acquire and visualize the patient's digital information, such as point cloud data in the transverse, sagittal, and coronal planes; performs registration and fusion of the patient's multimodal image data; reconstructs the patient's three-dimensional model according to the settings of the image interaction submodule; and reconstructs the model according to the three-dimensional point cloud file imported by the first model import module.

2. The robot-assisted craniofacial osteotomy internal fixation plate design and shaping system according to claim 1, characterized in that: The image interaction submodule includes a parameter setting module, which is used to set the parameters of 3D reconstruction, including isosurfaces and HU values, and can adjust the effect of 3D reconstruction. Based on the acquired point cloud data and the interactive peripheral, the starting point and ending point of the osteotomy line are set by selecting the point cloud data. The osteotomy line can be single or multiple. The osteotomy surface is set based on the osteotomy line as an edge. The osteotomy surface can be single or multiple. The size and vector direction of the osteotomy surface can be adjusted based on the osteotomy line. When single or multiple osteotomy surfaces are combined, the point cloud data is divided into different combinations. One or more point cloud data can be selected to be combined into a free bone segment. Based on the needs of orthognathic surgery, the three-dimensional poses of one or more free bone segments are defined in the patient's three-dimensional model, thereby planning and obtaining a patient three-dimensional model including the three-dimensional poses of the osteotomy line and osteotomy surface, as well as the final target pose of the free bone segments.

3. The robot-assisted craniofacial osteotomy internal fixation plate design and shaping system according to claim 2, characterized in that: The first model import module is used to import three-dimensional point cloud files, including STL format files. The STL format files are the intermediate occlusal plate, terminal occlusal plate, and free bone segments of the patient after demolding or digital scanning. After the STL format files are imported, the image processing submodule performs three-dimensional reconstruction into an STL model. The STL model and the reconstructed three-dimensional model of the patient are registered through coordinate matching and then displayed in the three-dimensional model of the patient. ① When the imported model is a free bone segment, the osteotomy line, osteotomy surface and free bone segment are set in the patient's 3D model based on the point cloud data covered by the registered STL model; the set free bone segment is 3D pose set in the patient's 3D model by the image interaction submodule. ② The imported model is the intermediate occlusal plate or the terminal occlusal plate. The three-dimensional pose of the free bone segment is adjusted in the patient's three-dimensional model so that the free bone segment matches the intermediate occlusal plate or the terminal occlusal plate, thereby planning and obtaining a patient three-dimensional model including the three-dimensional pose of the osteotomy line and osteotomy surface as well as the final target pose of the free bone segment.

4. The robot-assisted craniofacial osteotomy internal fixation plate design and shaping system according to claim 3, characterized in that: The internal fixation plate design module consists of an internal fixation plate library, a design interaction submodule, and a mechanical analysis submodule. The internal fixation plate library pre-sets various shapes of internal fixation plates, including straight, T-shaped, I-shaped, L-shaped, and Y-shaped; it also pre-sets various thicknesses of internal fixation plates, including 0.5mm, 0.7mm, 1mm, 1.2mm, and 1.5mm; it pre-sets various materials of internal fixation plates, including titanium alloy, PLA, PEEK, and PGA; and it pre-sets various mechanical parameters of internal fixation plate materials, including elastic modulus, Poisson's ratio, yield strength, tensile strength, and plastic hardening. ① The design of the interaction submodule involves acquiring a 3D model of the patient through the osteotomy data acquisition module, including the 3D pose of the osteotomy line and osteotomy surface, as well as the 3D model of the final target pose of the free bone segment; selecting a fixation area on the 3D model of the patient planned in the osteotomy data acquisition module; selecting the thickness and material of the fixation plate; and retrieving data from the internal fixation plate library based on the shape and size of the selected fixation area and the curvature of the bone surface to initially generate the position, shape, and size of the internal fixation plate. ② When the image processing submodule loads QCT data, the fixation area is selected on the patient's 3D model planned in the osteotomy data acquisition module; the internal fixation plate is automatically generated. The module retrieves internal fixation plate library data based on QCT data, bone surface curvature and the shape and size of the fixation area, and automatically generates the position, shape, size, material and thickness of the internal fixation plate.

5. The robot-assisted craniofacial osteotomy internal fixation plate design and shaping system according to claim 4, characterized in that: The mechanical analysis module allows setting loads and boundary conditions, such as defining load types (static biting force 300N, dynamic cyclic load 50-500N@2Hz, fixation at both ends of the bone plate, and simulating screw constraints). Based on the patient's 3D model (including the osteotomy line and osteotomy surface, the final target pose of the free bone segment), and the position, shape, size, material, and thickness of the internal fixation plate, the module performs a finite element analysis of the internal fixation plate's stress. The finite element analysis outputs stress cloud diagrams, displacement fields, strain energy density distribution results, and provides improvement suggestions. Based on the finite element analysis results, the parameters of the internal fixation plate in the design interaction submodule are modified, and the stress is repeated. The analysis continues until the results meet the requirements. When the results meet the requirements, the internal fixation plate is generated. Based on the simulation results, the fixation holes of the internal fixation plate and the fixation holes of the bone are automatically generated. The final internal fixation plate will be output as an STL file. The fixation holes of the bone are added to the patient's three-dimensional model in the form of a three-dimensional pose. The fixation holes of the bone are divided into fixation holes on free bone segments and fixation holes on non-free bone segments. The fixation holes on free bone segments are recalculated based on the movement pose relationship between the free bone segments and the non-free bone segments to perform the surgical drilling pose. The mechanical analysis model is based on open source libraries such as CalculiX, Code_Aster or commercial software, including the ANSYS API.

6. The robot-assisted craniofacial osteotomy internal fixation plate design and shaping system according to claim 5, characterized in that: The output module of the internal fixation plate design system includes the three-dimensional pose of the osteotomy line and osteotomy surface, as well as the final target pose of the free bone segment, the drill hole pose of the non-free bone segment, and the patient's three-dimensional model of the drill hole pose for the free bone segment surgery, including the shape, size, thickness, and material of the internal fixation plate STL file.

7. The robot-assisted craniofacial osteotomy internal fixation plate design and shaping system according to claim 6, characterized in that: The second model import module is used to import the STL file of the inner fixation plate and set the outer expansion area of ​​the 3D printing of the inner fixation plate according to the material, shape and size of the inner fixation plate. The 3D printing module prints the primary inner fixation plate based on the imported STL file of the inner fixation plate and the set outer expansion area.

8. The robot-assisted craniofacial osteotomy internal fixation plate design and shaping system according to claim 7, characterized in that: The station conversion module consists of an XYZ motion platform and a fixture mounted on it. After the 3D printing of the primary inner fixing plate is completed and it has been completely cooled, the station conversion module sends the primary inner fixing plate to the detection station of the detection module. The detection module consists of a three-dimensional surface optical scanning device and an image processing module. The three-dimensional surface optical scanning device is used to acquire the surface point cloud data of the primary internal fixation plate and send it to the image processing module. The image processing module performs coordinate registration and fusion of the surface point cloud data of the primary internal fixation plate with the imported STL data and compares the differences with the imported STL data. When the surface conformity between the primary internal fixation plate and the imported STL data meets the standard, the station transformation module sends the primary internal fixation plate to the cutting station of the laser cutting module.

9. The robot-assisted craniofacial osteotomy method and internal fixation plate design and shaping system according to claim 8, characterized in that: The laser cutting module will cut and drill fixing holes in the primary internal fixation plate according to the registration and fusion results of the acquired surface point cloud data of the primary internal fixation plate and the imported STL data, to obtain the secondary internal fixation plate. After the secondary internal fixation plate is cut, the station transformation module will send the secondary internal fixation plate to the detection station of the detection module. The image processing module will perform coordinate registration and fusion of the acquired surface point cloud data of the secondary internal fixation plate and the imported STL data, and compare the differences with the imported STL data. When the surface conformity between the secondary internal fixation plate and the imported STL data meets the standard, the internal fixation plate is shaped. The workstation conversion module sends the inner fixing plate into the polishing module for polishing, and the polishing module uses magnetic fluid polishing.

10. A robot-assisted craniofacial osteotomy method, characterized in that: Includes the following steps: S1. The output module of the internal fixation plate design system includes the three-dimensional pose of the osteotomy line and osteotomy surface, the final target pose of the free bone segment, the drill hole pose of the non-free bone segment, the three-dimensional model of the patient with the drill hole pose for the free bone segment surgery, the patient in physical space, and the robot. The coordinate registration module is used to register the coordinates of the robot. The coordinate registration module can be either infrared binocular vision or 3D structured light. The robot is a six-axis or seven-axis serial collaborative arm with force feedback function. S2. Convert the three-dimensional pose of the osteotomy line and osteotomy surface, the pose of the drill hole in the non-free bone segment, and the pose of the drill hole for the free bone segment into the robot's spatial pose; convert the patient in the physical space into the robot coordinate system; S3. The robot and osteotomy tools, including a micro drill and a reciprocating saw, are used to drill fixed holes according to the drilling hole position of the non-free bone segment and the drilling hole position of the free bone segment during surgery. S4. After drilling is completed, the robot and the osteotomy tools set at its end, including a micro drill and a reciprocating saw, perform osteotomy according to the three-dimensional pose of the osteotomy line and osteotomy surface. S5. Finally, align the fixation holes of the internal fixation plate with the non-free bone segments and lock them with screws in sequence. Then align the fixation holes on the cut free bone segments with the fixation holes on the internal fixation plate and lock them in sequence.

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