Intraoperative omnidirectional tracing probe based on optical marker and parameter optimization method thereof

Abstract

The invention discloses an intraoperative omnidirectional tracing probe based on an optical marker and a parameter optimization method of the intraoperative omnidirectional tracing probe. The intraoperative omnidirectional tracing probe comprises a sampling probe and an optical marker array, the sampling probe comprises a long and thin rod-shaped probe body; a hook-shaped needle point is arranged at the front end of the probe body; the hook-shaped needle tip can flexibly enter different directions in a narrow space of an articular cavity, so that fixed-point sampling of subchondral tissues, synovial membranes and local focus tissues is realized; the optical mark array is installed at the tail end of the probe body and comprises at least five near-optical reflective mark balls of an asymmetric structure. The at least five near-optical reflective marking balls are non-coplanar in space and have a multi-ball coplanar distribution structure. The intraoperative omni-directional tracing probe has high flexibility and high recognition degree, and omni-directional sampling and accurate navigation positioning can be achieved in the complex space environment of an articular cavity.

Description

Technical Field

[0001] This invention belongs to the field of medical device and computer-aided surgical navigation technology, specifically relating to an intraoperative omnidirectional tracer probe based on optical markers and its parameter optimization method, used for intra-articular sampling in orthopedic surgery, and is particularly suitable for omnidirectional spatial identification and positioning in navigation systems. Background Technology

[0002] In existing orthopedic arthroscopic or navigation surgical systems, sampling probes are mostly linear in structure, primarily suitable for sampling the bone surface or superficial tissues. However, inside the joint cavity, due to limited space, complex angles, and dense tissue structures, traditional straight probes struggle to effectively penetrate deep into the joint cavity for directional sampling, resulting in limited sampling angles, inflexible operation, and decreased positioning accuracy.

[0003] Meanwhile, most existing navigation systems rely on arrays of reflective markers for spatial attitude recognition. These marker arrays are generally planar, symmetrical, or randomly distributed.

[0004] For a planar array of markers, since all markers are coplanar, the system can only track the probe's orientation in a hemispherical space (approximately 180°). When the probe rotates beyond this range around the plane normal, the optical camera will not be able to effectively capture all markers, resulting in recognition loss and failing to meet the omnidirectional tracking requirements of intra-articular sampling probes.

[0005] While symmetrically distributed marker arrays can theoretically achieve omnidirectional sampling and all-attitude recognition, this structure requires the probe tip to be strictly coaxial with the array's axis of symmetry. Therefore, it is only suitable for linear probe structures. Once the probe tip has a curved structure, such as a hooked or curved tip, the probe's actual working axis will no longer coincide with the marker array axis, causing the navigation system to fail to correctly calculate the tip position or angle. Furthermore, symmetrically distributed marker arrays lack a spatial calibration mechanism for hooked probe tips. When the probe tip undergoes bending deformation after use, errors occur in the entire system's pose calculation, ultimately leading to a significant deviation between the sampling point location and the actual anatomical location, failing to meet the requirements of flexible operation and precise spatial positioning in orthopedic surgery.

[0006] In addition, some studies have attempted to use randomly distributed multi-sphere optical marker arrays to achieve omnidirectional recognition. Although random placement can avoid recognition ambiguity caused by symmetry to some extent, the lack of a four-sphere coplanar relationship in its distribution makes normal vector-based attitude calibration impossible. Such random arrays have significant limitations in clinical navigation systems, making it difficult to guarantee high recognition accuracy.

[0007] Therefore, there is an urgent need for an innovative probe that is suitable for sampling the complex space of the joint cavity and has a highly recognizable optical marker array structure. Summary of the Invention

[0008] This invention provides an intraoperative omnidirectional tracer probe based on optical markers and its parameter optimization method. The intraoperative omnidirectional tracer probe has both high flexibility and high recognition, and can achieve omnidirectional sampling and precise navigation and positioning in the complex spatial environment of the joint cavity.

[0009] To achieve the above objectives, the present invention adopts the following specific technical solution: First, the present invention provides an intraoperative omnidirectional tracer probe based on optical markers, which includes a sampling probe and an optical marker array; The sampling probe includes a probe body in the shape of a slender rod; the front end of the probe body is provided with a hook-shaped needle tip; the hook-shaped needle tip can flexibly enter different directions within the narrow space of the joint cavity to achieve targeted sampling of subchondral tissue, synovium and local lesion tissue; The optical marker array is installed at the tail end of the probe body and includes at least five near-optical reflective marker spheres with an asymmetric structure. The at least five near-optical reflective marker spheres are non-coplanar in space and have a multi-sphere coplanar distribution structure. The distance between any two near-optical reflective marker spheres is not equal and the distance difference is not less than 5 mm. The minimum distance between any two near-optical reflective marker spheres is not less than 50 mm.

[0010] Furthermore, the optical marker array adopts a triangular pyramidal hexagonal reflective sphere array structure and includes six near-optical reflective marker spheres; The centers of the six near-optical reflective marker spheres form an asymmetric triangular pyramid geometry in three-dimensional space. Three of the six near-optical reflective marker spheres are arranged at the apex of the base of the triangular pyramid to form a bottom triangle structure, while the other three are located on the three side edges to form three waistlines. They also form three sets of non-coplanar planes composed of four marker spheres, thus achieving three-dimensional omnidirectional recognition and high-precision pose calibration capabilities.

[0011] Furthermore, an optical marker array holder is provided at the tail end of the probe body; The at least five near-optical reflective marker balls are detachably mounted on the optical marker array mounting base.

[0012] Furthermore, the length of the hook-shaped needle tip is 5mm.

[0013] Furthermore, the sampling probe is made of medical-grade metal material; the optical marker array holder is made of high-strength, lightweight medical-grade metal material.

[0014] Furthermore, the sampling probe is also equipped with a handle.

[0015] In addition, the present invention also provides a parameter optimization method for an intraoperative omnidirectional tracer probe used in the above-mentioned technical solution, the parameter optimization method comprising the following steps: Step 1, Modeling; Step 2: Construct the objective function for optimization; Step 3: The objective function is optimized using the differential evolution algorithm.

[0016] Furthermore, step one specifically includes: By defining the three vertices of the base triangle of the optical marker array D , E , F Two-dimensional coordinates and the vertex above them H Define a basic triangular pyramid space; On the three lateral edges DH , EH , FH Take three parameterized points respectively A , B , C This forms six spatial points, and the geometric relationship between these six spatial points can be expressed as:

[0017]

[0018]

[0019] In the above formula, t 1. t 2. t 3 are all distribution parameters on the lateral edges and all ∈ [0,1].

[0020] Furthermore, step two specifically includes: The loss function is defined with the objectives of minimizing the overall size of the optical marker array and maximizing the stability of optical recognition. L :

[0021] In the above formula, The Euclidean distance between any two near-optical reflective marker spheres; The minimum distance constraint penalty term ensures the minimum distance between any two near-optical reflective marker spheres. ; As a distance difference penalty, ensure that each distance difference ; A high-constraint penalty term is used to ensure the three-dimensionality of the array space.

[0022] Furthermore, step three specifically includes: Multiple individuals are randomly generated within a set parameter space to form an initial population; The population is continuously updated through differential mutation, crossover, and selection operations; Calculate the objective function value in each generation and retain the individual with the highest fitness. Repeat the iterations until convergence, and obtain the optimal set of parameters.

[0023] Compared with the prior art, the technical solution of the present invention has the following beneficial effects: 1. Larger sampling space and significantly improved angular freedom.

[0024] Compared with existing straight probes that are only suitable for locating prominent bony areas, the intraoperative omnidirectional tracing probe of the present invention has a hook-shaped needle tip at the front end of the probe body. This hook-shaped needle tip allows for flexible operation in the narrow space inside the joint cavity. The hook-shaped needle tip makes the sampling direction no longer limited to the probe axis direction, enabling multi-angle and all-round tissue sampling, which is especially suitable for deep tissue sampling of complex joints such as hip, knee, and shoulder.

[0025] Meanwhile, when used in conjunction with a navigation system, the hook-shaped needle tip can maintain a precise correspondence between the needle tip and the target tissue, greatly improving the controllability and operational flexibility of the probe in three-dimensional space, and fundamentally solving the problems of limited sampling space and difficulty in angle adjustment of traditional probes.

[0026] 2. It achieves omnidirectional posture recognition, is not limited by the shape of the pin tip, and has high recognition accuracy.

[0027] Compared to existing planar or symmetrical optical marker arrays, this invention employs an asymmetrical triangular pyramidal hexa-reflective sphere optical marker array design. This design distributes the centers of the six near-optical reflective marker spheres across three non-coplanar planes, forming a unique spatial geometric configuration. This structure possesses a unique and identifiable spatial coordinate relationship at any rotation angle, thereby achieving true 360° omnidirectional attitude tracking.

[0028] Meanwhile, the optical marker array contains three sets of planes composed of four spheres, which can be used as normal vector constraint surfaces for high-precision pose calibration, thereby significantly improving the system's pose solution accuracy and robustness while maintaining omnidirectional recognition capability.

[0029] Furthermore, the optical marker array design is not strictly collinear with the probe body axis. By pointing the probe tip at a fixed point and performing multiple samples, for the i-th sample, These are the rotation matrix and translation vector of the optical marker array, respectively. It is the offset vector from the needle tip to the array of optical markers, and the coordinates of the needle tip in the world coordinate system. p i It can be represented as:

[0030] Multiple sets of equations are constructed, and then the needle tip offset is solved. This method ensures accurate coordinate calculations even when the needle tip is bent or deviated. This design enables the invention to achieve high-precision attitude recognition and navigation positioning of hook-shaped probes for the first time, overcoming the limitation of existing technologies that cannot recognize non-linear needle tips.

[0031] 3. Global optimization design of optical marker array based on differential evolution algorithm.

[0032] Unlike traditional methods that rely on experience to determine the placement of optical markers, this invention introduces a systematic geometric optimization algorithm. By establishing a mathematical model with multiple constraints (minimum distance, distance difference, spatial height, and volume constraints) and using a differential evolution algorithm for global search optimization, this algorithm can automatically find the optimal solution for the distribution of marker spheres in a high-dimensional parameter space, ensuring that: the distances between each marker sphere are unequal and the difference is greater than 5mm to avoid confusion in system recognition; the minimum distance between each marker point is not less than 50mm to ensure spatial resolution; and the overall array volume is minimized, reducing structural size and improving the convenience of surgical operation.

[0033] Through the optimization methods described above, the optical marker array obtained by this invention forms a highly asymmetric and stable geometric relationship in three-dimensional space, significantly improving its recognition robustness and enabling the navigation system to maintain high-precision positioning even under complex postures. Compared with traditional empirical design, this invention achieves a technological leap from manual layout to algorithm-optimized layout, significantly improving the engineering reliability and batch consistency of the probes.

[0034] Therefore, this invention achieves the transformation of optical marker arrays from empirical design to parametric intelligent design by combining geometric structure innovation with evolutionary optimization algorithms, which significantly improves the identification accuracy, attitude stability and operational flexibility of sampling probes in surgical navigation systems. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the intraoperative omnidirectional tracer probe of the present invention; Figure 2 This is a schematic diagram of the center of an optical marker array.

[0036] Figure label: 1-Sampling probe, 2-Optical marker array, 11-Hook-shaped needle tip, 12-Optical marker array holder, 13-Handle. Detailed Implementation

[0037] 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.

[0038] Example 1 This embodiment provides an intraoperative omnidirectional tracing probe based on optical markers, such as Figure 1 As shown in the structure, the intraoperative omnidirectional tracer probe includes a sampling probe 1 and an optical marker array 2; wherein: The sampling probe 1 includes a slender, rod-shaped probe body; the sampling probe 1 can be made of medical-grade metal material. A hook-shaped needle tip 11 is provided at the front end of the probe body; the length of the hook-shaped needle tip 11 can be 5 mm. The hook-shaped needle tip 11 can flexibly enter into different directions within the narrow space of the joint cavity, achieving targeted sampling of subchondral tissue, synovium, and local lesions. A handle 13 is provided at the rear end of the sampling probe 1.

[0039] An optical marker array 2 is mounted at the tail end of the probe body and includes at least five near-optical reflective marker spheres with an asymmetrical structure. An optical marker array mounting base 12 may be provided at the tail end of the probe body; the at least five near-optical reflective marker spheres are detachably mounted on the optical marker array mounting base 12. The optical marker array mounting base 12 may be made of a high-strength, lightweight medical metal material. The at least five near-optical reflective marker spheres are distributed in a non-coplanar manner in space, with some spheres coplanar. The distance between any two near-optical reflective marker spheres is unequal, with a distance difference of not less than 5 mm, and the minimum distance between any two near-optical reflective marker spheres is not less than 50 mm.

[0040] The aforementioned probe features a hook-shaped tip 11 at its front end. This hook-shaped tip allows for flexible adjustment of the sampling direction, enabling multi-angle and omnidirectional tissue sampling within the joint cavity. This effectively solves the problems of limited space and insufficient angular freedom inherent in traditional probes. The hook-shaped tip 11 allows for flexible operation within the narrow space of the joint cavity. It also frees the sampling direction from being limited to the probe axis, enabling multi-angle and omnidirectional tissue sampling, making it particularly suitable for deep tissue sampling in complex joints such as the hip, knee, and shoulder. Furthermore, when used in conjunction with a navigation system, the hook-shaped tip 11 maintains a precise correspondence between the tip and the target tissue, significantly improving the probe's controllability and operational flexibility in three-dimensional space, fundamentally solving the problems of limited sampling space and difficult angle adjustment inherent in traditional probes.

[0041] In this embodiment, an optical marker array 2 employing a triangular pyramidal hexagonal reflective sphere array structure will be used as an example for explanation. Figure 1 As shown, the optical marker array 2 includes six near-optical reflective marker spheres; the centers of the six near-optical reflective marker spheres form an asymmetric triangular pyramid geometry in three-dimensional space; three of the six near-optical reflective marker spheres are arranged at the apex of the base of the triangular pyramid to form a bottom triangle structure, and the other three are located on the three side edges to form three waistlines, forming three sets of non-coplanar planes composed of four marker spheres, thus realizing three-dimensional omnidirectional recognition and high-precision pose calibration capabilities.

[0042] The probe employs an asymmetric triangular pyramidal hexacopter optical marker array 2 structure. The six reflective marker spheres of this array are distributed on three non-coplanar planes, forming a unique and stable spatial geometric relationship, enabling omnidirectional attitude recognition and stable spatial calculation. This structure possesses a uniquely identifiable spatial coordinate relationship at any rotation angle, thus achieving true 360° omnidirectional attitude tracking. Simultaneously, within the optical marker array 2, there are three sets of four-sphere planes that can serve as normal vector constraint surfaces for high-precision pose calibration, thereby significantly improving the system's attitude solution accuracy and robustness while maintaining omnidirectional recognition capabilities.

[0043] Furthermore, the optical marker array 2 is not strictly collinear with the probe body axis. By pointing the probe tip to a fixed point and performing multiple samples, for the i-th sample, These are the rotation matrix and translation vector of the optical marker array, respectively. It is the offset vector from the needle tip to the array of optical markers. The coordinates of the needle tip in the world coordinate system can be expressed as:

[0044] Multiple sets of equations are constructed, and then the needle tip offset is solved. This method enables accurate coordinate calculation even when the needle tip is bent or deviated. This design allows the invention to achieve high-precision attitude recognition and navigation positioning of hook-shaped probes for the first time, overcoming the limitation of existing technologies that cannot recognize non-linear needle tips.

[0045] Example 2 This invention proposes a geometric optimization method for optical reflective sphere arrays based on differential evolution algorithms. By introducing minimum distance constraints, distance difference constraints, and a volume minimization objective function, the method achieves global optimization of the reflective sphere array's arrangement in multi-dimensional space. This method not only ensures the unique identification relationship between optical marker points but also significantly reduces the overall array volume, thereby improving the spatial positioning accuracy and structural stability of the navigation system while maintaining high recognition robustness.

[0046] The parameter optimization method of this invention is used for the intraoperative omnidirectional tracer probe of the above embodiments. The parameter optimization method includes the following steps: Step 1, Modeling: Define the three vertices of the base triangle of optical marker array 2. D , E , F Two-dimensional coordinates and the vertex above them H Define a basic triangular pyramid space; On the three lateral edges DH , EH , FH Take three parameterized points respectively A , B , C This forms six spatial points, and the geometric relationship between these six spatial points can be expressed as:

[0047]

[0048]

[0049] In the above formula, t 1. t 2. t 3 are all distribution parameters on the lateral edges and all ∈ [0,1].

[0050] Step 2, construct the optimization objective function: Define the loss function with the objectives of minimizing the overall size of the optical marker array 2 and maximizing optical recognition stability. L :

[0051] In the above formula, The Euclidean distance between any two near-optical reflective marker spheres; The minimum distance constraint penalty term ensures the minimum distance between any two near-optical reflective marker spheres. ; As a distance difference penalty, ensure that each distance difference ; A high-constraint penalty term is used to ensure the three-dimensionality of the array space.

[0052] Step 3: Optimize the objective function using the differential evolution algorithm, specifically including: Multiple individuals are randomly generated within a set parameter space to form an initial population; The population is continuously updated through differential mutation, crossover, and selection operations; Calculate the objective function value in each generation and retain the individual with the highest fitness. Repeat the iterations until convergence, and obtain the optimal set of parameters.

[0053] The aforementioned parameter optimization method introduces a systematic geometric optimization algorithm. By establishing a mathematical model containing multiple constraints (minimum distance, distance difference, spatial height, and volume constraints), and using a differential evolution algorithm for global search optimization, this algorithm can automatically find the optimal solution for the distribution of marker balls in a high-dimensional parameter space, ensuring that: the distances between each marker ball are not equal and the difference is greater than 5mm to avoid confusion in system identification; the minimum distance between each marker point is not less than 50mm to ensure spatial resolution; and the overall volume of the array is minimized, reducing structural size and improving the convenience of surgical operation.

[0054] The optical marker array 2 obtained through the above parameter optimization method forms a highly asymmetric and stable geometric relationship in three-dimensional space, significantly improving its recognition robustness and enabling the navigation system to maintain high-precision positioning even under complex postures. Compared with traditional empirical design, this invention achieves a technological leap from manual layout to algorithm-optimized layout, significantly improving the engineering reliability and batch consistency of the probes.

[0055] Therefore, this invention achieves the transformation of the optical marker array 2 from empirical design to parametric intelligent design by combining geometric structure innovation and evolutionary optimization algorithm, which significantly improves the recognition accuracy, attitude stability and operation flexibility of the sampling probe 1 in the surgical navigation system.

[0056] Obviously, those skilled in the art can make various modifications and variations to the embodiments of the present invention without departing from the spirit and scope of the invention. Therefore, if these modifications and variations fall within the scope of the claims of the present invention and their equivalents, the present invention also intends to include these modifications and variations.

[0057] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An intraoperative omnidirectional tracing probe based on optical markers, characterized in that, Includes sampling probes and optical marker arrays; The sampling probe includes a probe body in the shape of a slender rod; the front end of the probe body is provided with a hook-shaped needle tip; the hook-shaped needle tip can flexibly enter different directions within the narrow space of the joint cavity to achieve targeted sampling of subchondral tissue, synovium and local lesion tissue; The optical marker array is installed at the tail end of the probe body and includes at least five near-optical reflective marker spheres with an asymmetric structure. The at least five near-optical reflective marker spheres are non-coplanar in space and have a multi-sphere coplanar distribution structure. The distance between any two near-optical reflective marker spheres is not equal and the distance difference is not less than 5 mm. The minimum distance between any two near-optical reflective marker spheres is not less than 50 mm.

2. The intraoperative omnidirectional tracing probe as described in claim 1, characterized in that, The optical marker array adopts a triangular pyramidal six-reflective sphere array structure and includes six near-optical reflective marker spheres; The centers of the six near-optical reflective marker spheres form an asymmetric triangular pyramid geometry in three-dimensional space. Three of the six near-optical reflective marker spheres are arranged at the apex of the base of the triangular pyramid to form a bottom triangle structure, while the other three are located on the three side edges to form three waistlines. They also form three sets of non-coplanar planes composed of four marker spheres, thus achieving three-dimensional omnidirectional recognition and high-precision pose calibration capabilities.

3. The intraoperative omnidirectional tracing probe as described in claim 2, characterized in that, The probe body is provided with an optical marker array fixing base at its tail end; The at least five near-optical reflective marker balls are detachably mounted on the optical marker array mounting base.

4. The intraoperative omnidirectional tracing probe as described in claim 1, characterized in that, The length of the hook-shaped needle tip is 5mm.

5. The intraoperative omnidirectional tracing probe as described in claim 3, characterized in that, The sampling probe is made of medical-grade metal material; the optical marker array holder is made of high-strength, lightweight medical-grade metal material.

6. The intraoperative omnidirectional tracing probe as described in any one of claims 1-5, characterized in that, The sampling probe is also equipped with a handle.

7. A method for optimizing parameters of the intraoperative omnidirectional tracer probe according to any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Modeling; Step 2: Construct the objective function for optimization; Step 3: The objective function is optimized using the differential evolution algorithm.

8. The parameter optimization method as described in claim 7, characterized in that, Step one specifically includes: By defining the three vertices of the base triangle of the optical marker array D , E , F Two-dimensional coordinates and the vertex above them H Define a basic triangular pyramid space; On the three lateral edges DH , EH , FH Take three parameterized points respectively A , B , C This forms six spatial points, and the geometric relationship between these six spatial points can be expressed as: In the above formula, t 1. t 2. t 3 are all distribution parameters on the lateral edges and all ∈ [0,1].

9. The parameter optimization method as described in claim 8, characterized in that, Step two specifically includes: The loss function is defined with the objectives of minimizing the overall size of the optical marker array and maximizing the stability of optical recognition. L : In the above formula, The Euclidean distance between any two near-optical reflective marker spheres; The minimum distance constraint penalty term ensures the minimum distance between any two near-optical reflective marker spheres. ; As a distance difference penalty, ensure that each distance difference ; A high-constraint penalty term is used to ensure the three-dimensionality of the array space.

10. The parameter optimization method according to any one of claims 7-9, characterized in that, Step three specifically includes: Multiple individuals are randomly generated within a set parameter space to form an initial population; The population is continuously updated through differential mutation, crossover, and selection operations; Calculate the objective function value in each generation and retain the individual with the highest fitness. Repeat the iterations until convergence, and obtain the optimal set of parameters.

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