Patent Publication Number: US-2021174950-A1

Title: Stereoscopic marker device and three-dimensional real-time positioning method of orthopedic surgery

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of Taiwan Patent Application No. 108144741, filed on Dec. 6, 2019, which is hereby incorporated by reference for all purposes as if fully set forth herein. 
     BACKGROUND 
     Technical Field 
     The present disclosure relates to a stereoscopic marker device and a three-dimensional real-time positioning method of orthopedic surgery, and in particular, to a three-dimensional real-time positioning method of orthopedic surgery by using a stereoscopic marker device. 
     Related Art 
     A surgical navigation system is an important development direction of precision and micro invasion of orthopedically surgical treatment, and an optical surgical navigation technology is most widely used. A pasted marker has smaller scratch and easier operation than a mechanical fixing device, is more precise than an anatomical marker, and is widely used. The optical surgical navigation system performs tracking and positioning by tracking points of the pasted marker on patients and surgical tools. The points of the pasted marker and a lesion position are determined by a three-dimensional medical image before surgery. The optical surgical navigation system tracks the points of the pasted marker on the patient by a positioning device in surgery, to obtain a posture of the patient in real time, and coverts the posture of the patient into an image coordinate system for display after three-dimensional medical image is registrated before the surgery. 
     The existing optical surgical navigation system has the following disadvantages: first, the points of the marker may fall during the surgical navigation process and needs to be re-registered; second, light reflected from the points of the marker may be obscured; in addition, some surgical sites are not convenient to paste the points of the marker. 
     China Patent Application Publication No. CN106214256A discloses a non-marker optical surgical navigation system and a navigation method thereof. The non-marker optical surgical navigation system includes a structured light three-dimensional scanning system, an optical positioning system, a calibration board, and a graphic workstation. The non-marker optical surgical navigation system continuously obtains surface information of a surgical area of a patient by using the structured light three-dimensional scanning system, thereby obtaining surface three-dimensional coordinates of the patient. A coordinate transformation relationship is obtained by using the surface three-dimensional coordinates of the patient in real time and the three-dimensional medical image registration of the patient before surgery. Meanwhile, a position of a surgical instrument is tracked in real time by using the near-infrared optical positioning system. Finally, the three-dimensional medical image of the surgical site of the patient and surgical tools are displayed on a display device. This patent document implements the optical surgical navigation of patients without marker, and does not require a doctor to manually register the marker. Therefore, an operation process and surgical time are reduced, a problem of falling of the marker is resolved, and meanwhile, use in an occasion in which some surgical sites are not convenient to paste the marker is facilitated. 
     However, lack of sufficient points of the marker in the patent document may result in lack of a direction in positioning, and therefore, precise positioning is impossible. 
     Therefore, a three-dimensional real-time positioning method of orthopedic surgery applied to a surgical navigation system needs to be provided, to resolve the foregoing problem. 
     SUMMARY 
     An objective of the present disclosure is to provide a three-dimensional real-time positioning method of orthopedic surgery by using a stereoscopic marker device. 
     To achieve the foregoing objective, the present disclosure discloses a stereoscopic marker device, comprising: a polyhedral cube, comprising at least four flat surfaces, wherein the at least four flat surfaces are used as one primary marker and at least three secondary markers respectively, the primary marker comprises a primary graphic code, the three secondary markers individually comprise a first secondary graphic code, a second secondary graphic code, and a third secondary graphic code, and the primary graphic code is used for providing spatial coordinate information, which is used for calculating six degrees of freedom (DOF) attitude data; and a spike-shaped body, combined with the polyhedral cube and configured to be fixed on a surgical site. 
     The present disclosure further discloses a three-dimensional real-time positioning method of orthopedic surgery, comprising the following steps: providing at least one stereoscopic marker device; fixing the at least one stereoscopic marker device on a surgical site; setting up an optical positioning system, wherein the optical positioning system comprises two six degrees of freedom (DOF) photographic devices, which are set as a primary photographic device and a secondary photographic device located at two sides of the surgical site respectively; calibrating the primary photographic device and the secondary photographic device; starting a six DOF calculation module; conforming that both of the primary photographic device and the secondary photographic device can recognize the polyhedral cube; determining whether the polyhedral cube of the stereoscopic marker device is obscured to cause the primary photographic device to fail in shooting; shooting the polyhedral cube of the stereoscopic marker device by using the primary photographic device when the polyhedral cube is not obscured; switching to shoot the polyhedral cube of the stereoscopic marker device by the secondary photographic device when the polyhedral cube is obscured; determining whether the primary marker of the polyhedral cube of the stereoscopic marker device is obscured to cause the primary photographic device or the secondary photographic device to fail in shooting; providing spatial coordinate information by using the primary graphic code of the primary marker when the primary marker is not obscured, to finish calculating six DOF attitude data; and calculating spatial coordinate information of the primary marker by using the first secondary graphic code to the third secondary graphic code of the three secondary markers when the primary marker is obscured, to finish calculating six DOF attitude data. 
     Beneficial effects of the present disclosure are as follows: First, the three-dimensional real-time positioning method of orthopedic surgery provided in the present disclosure can be a three-dimensional real-time positioning method of spine surgery, and the six DOF attitude data is calculated by the spike-shaped body (i.e., spinal spike) combined with the polyhedral cube (i.e., ceramic stereoscopic marker) to precisely position vertebral segment. After the six DOF photographic devices shoot the stereoscopic marker device a registration of the stereoscopic marker device is completed. A plurality of flat surfaces of different markers are set on the stereoscopic marker device on the spinal spike, and thus the six DOF attitude data (i.e., position data) of the stereoscopic marker device can be calculated when the six DOF photographic devices shoot one primary marker or three secondary markers of the polyhedral cube. Second, the concept of primary and secondary markers is introduced to the stereoscopic marker device of the present disclosure. When the primary marker is obscured, spatial coordinate information of the primary marker is calculated in real time by peripheral secondary markers, to ensure that precise positioning of surgical site is not affected when medical workers or other objects obscure the stereoscopic marker device. Third, the stereoscopic marker device of the present disclosure has a QR code feature, image recognition can be improved, and image capturing efficiency of the six DOF photographic devices is further improved. Fourth, the present disclosure develops the stereoscopic marker device having a QR code feature by using a special material, and three-dimensional spatial coordinate information can be defined by a single stereoscopic marker device. Fifth, the three-dimensional real-time positioning method of orthopedic surgery of the present disclosure can be applied to a surgery navigation system. Signals of the surgery navigation system cannot be interfered when the stereoscopic marker device of the present disclosure is obscured by medical workers or other objects, thereby increasing the movable position of medical workers or other objects in an operating room, and reducing restriction on the movement of the medical workers in the operating room. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic perspective view of a stereoscopic marker device according to an embodiment of the present disclosure. 
         FIG. 2  is a schematic perspective view of a plurality of stereoscopic marker devices fixed on a surgical site according to an embodiment of the present disclosure. 
         FIG. 3  is a schematic perspective view of orthopedic surgery by using a plurality of stereoscopic marker devices fixed on a surgical site according to an embodiment of the present disclosure. 
         FIG. 4  is a flow chart of a three-dimensional real-time positioning method of orthopedic surgery according to an embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     To make the objectives, features, and characteristics of the present disclosure clearer and easier to understand, the following gives a detailed description of related embodiments of the present disclosure with reference to the accompanying drawings. 
       FIG. 1  is a schematic perspective view of a stereoscopic marker device according to an embodiment of the present disclosure.  FIG. 2  is a schematic perspective view of a plurality of stereoscopic marker devices fixed on a surgical site according to an embodiment of the present disclosure. The stereoscopic marker device  1  includes: a polyhedral cube  10  and a spike-shaped body  19 . The spike-shaped body  19  is combined with the polyhedral cube  10  and configured to be fixed on a surgical site  2 . When the surgical site  2  is a spine, the spike-shaped body  19  is a spinal spike. 
     The polyhedral cube  10  includes at least four flat surfaces, and the at least four flat surfaces are used as one primary marker  11  and at least three secondary markers  12  respectively. For example, the polyhedral cube  10  includes twelve flat surfaces, that is, the polyhedral cube  10  is a dodecahedral cube. The number of the at least three secondary markers  12  are eight. The primary marker  11  includes a primary graphic code  111 , and the three secondary markers  12  individually include a first secondary graphic code  121 , a second secondary graphic code  122 , and a third secondary graphic code  123 . In other words, the three secondary markers  12  can be first to third secondary markers, the first secondary marker includes the first secondary graphic code,  121 , the second secondary marker includes the second secondary graphic code  122 , and the third secondary marker includes the third secondary graphic code  123 . The primary graphic code  111  is used for providing spatial coordinate information, which is used for calculating six degrees of freedom (DOF) attitude data. For example, an object has six DOF in space, that is, moving DOF along directions of three rectangular coordinate axes X, Y, and Z and rotating DOF around the three coordinate axes. The primary graphic code  111  and the first to the third secondary graphic codes  121 ,  122 , and  123  are different quick response matrix graphic codes (QR codes). 
     A material of the polyhedral cube  10  of the stereoscopic marker device  1  can be a plastic medical material such as poly-ether-ether-ketone (PEEK). Alternatively, a material of the polyhedral cube  110  can be a ceramic material such as aluminum oxide. For example, a powder die-casting sintering process of the polyhedral cube  110  of the stereoscopic marker device  1  is as follows: First, a ceramic block material in accordance with recognition of an infrared ray (IR) light source is developed in a specific proportion formula of aluminum oxide material and adhesive. Second, the manufactured ceramic block material is ground by a diamond grinding wheel to manufacture the stereoscopic marker device required for a six DOF tracking technology. Finally, a quick response matrix graphic code (QR) code feature is processed on a surface of the polyhedral cube made of aluminum oxide by using a laser process. 
       FIG. 3  is a schematic perspective view of orthopedic surgery according to an embodiment of the present disclosure.  FIG. 4  is a flow chart of a three-dimensional real-time positioning method of orthopedic surgery according to an embodiment of the present disclosure. The three-dimensional real-time positioning method of orthopedic surgery includes the following steps. 
     Step S 10 . Provide the foregoing at least one stereoscopic marker device  1  of the present disclosure. Referring to  FIG. 1 , the stereoscopic marker device  1  includes: a polyhedral cube  10  and a spike-shaped body  19 . The polyhedral cube  10  includes at least four flat surfaces, and the at least four flat surfaces are used as one primary marker  11  and at least three secondary markers  12  respectively. The primary marker  11  includes a primary graphic code  111 , and the three secondary markers  12  individually include a first secondary graphic code  121 , a second secondary graphic code  122 , and a third secondary graphic code  123 . The primary graphic code  111  and the first to the third secondary graphic codes  121 ,  122 , and  123  are different QR codes. 
     Step S 20 . Fix the at least one stereoscopic marker device  1  on a surgical site  2 . When the surgical site  2  is a spine, a plurality of stereoscopic marker devices  1  are fixed on the surgical site  2  by the spike-shaped body  19  (that is, a spinal spike). Step S 30 . Set up an optical positioning system. The optical positioning system includes two six DOF photographic devices, which are set as a primary photographic device  31  and a secondary photographic device  32  located at two sides of the surgical site  2  respectively. Step S 40 . Calibrate the primary photographic device  31  and the secondary photographic device  32 . Step S 50 . Start a six DOF calculation module. The six DOF calculation module can be a processor having a calculation function. 
     Step S 55 . Confirm that both of the primary photographic device  31  and the secondary photographic device  32  can recognize the polyhedral cube. After software of the six DOF calculation module is started for the first time, subsequent procedures (steps S 60  to S 71 /S 72 ) can be continued only after it is determined that both of the primary photographic device  31  and the secondary photographic device  32  can recognize the polyhedral cube  10  of the stereoscopic marker device  1 . If one of the primary photographic device  31  and the secondary photographic device  32  cannot recognize the polyhedral cube  10 , positions of the primary photographic device  31  and the secondary photographic device  32  need to be adjusted until the polyhedral cube is visible to both of the primary and secondary photographic devices  31 ,  32 . Step S 60 . Determine whether the polyhedral cube  10  of the stereoscopic marker device  1  is obscured to cause the primary photographic device  31  to fail in shooting. Step S 71 . Shoot the polyhedral cube  10  of the stereoscopic marker device  1  by the primary photographic device  31  when the polyhedral cube  10  of the stereoscopic marker device  1  is not obscured. Step S 72 . Switch to shoot the polyhedral cube  10  of the stereoscopic marker device  1  by the secondary photographic device  32  when the polyhedral cube  10  of the stereoscopic marker device  1  is obscured. When the primary photographic device  31  or the secondary photographic device  32  shoots the polyhedral cube  10  of the stereoscopic marker device  1 , a registration of the stereoscopic marker device  1  is completed. 
     Step S 80 . Determine whether the primary marker  11  of the polyhedral cube  10  of the stereoscopic marker device  1  is obscured to cause the primary photographic device  31  or the secondary photographic device  32  to fail in shooting. Step S 91 . Provide spatial coordinate information by using the primary graphic code of the primary marker  11  when the primary marker  11  is not obscured, to enter step S 93 : Finish calculating six DOF attitude data. Step S 92 . Calculate spatial coordinate information of the primary marker  11  by using the first to the third secondary graphic codes  121 ,  122 , and  123  of the three secondary markers  12  when the primary marker  11  is obscured, to enter step S 93 : Finish calculating six DOF attitude data. 
     In this embodiment, a conversion is performed between an image coordinate system and a world coordinate system (WCS) by using a transposed matrix, to calculate the six DOF attitude spatial data (for example, an object has six DOF in space, that is, moving DOF along directions of three rectangular coordinate axes X, Y, and Z and rotating DOF around the three coordinate axes). For example, first, a WCS, a photographic device coordinate system, and an image coordinate system are defined, wherein the WCS is a common coordinate system. Then, image data shot by the photographic device is converted from the image coordinate system to the photographic device coordinate system, and converted from the photographic device coordinate system to the WCS. Through this conversion step, all coordinate values and vectors can be calculated with each other. In a traditional practice, after an origin of the WCS is preset in space, a position of the photographic device in the WCS and inner parameters of the photographic device are calibrated, to convert a coordinate value of a two-dimensional image shot by the photographic device into a world coordinate value of three-dimensional space, so that all coordinate systems can be converted with each other. A conversion relationship between the image coordinate system and the WCS is the transposed matrix, and moving DOF along directions of three rectangular coordinate axes X, Y, and Z and rotating DOF around the three coordinate axes of the object shot by the photographic device can be calculated by using the transposed matrix. 
     Beneficial effects of the present disclosure are as follows: First, the three-dimensional real-time positioning method of orthopedic surgery provided in the present disclosure can be a three-dimensional real-time positioning method of spine surgery, and the six DOF attitude data is calculated by the spike-shaped body (i.e., spinal spike) combined with the polyhedral cube (i.e., ceramic stereoscopic marker) to precisely position vertebral segment. After the six DOF photographic devices shoot the stereoscopic marker device a registration of the stereoscopic marker device is completed. A plurality of flat surfaces of different markers are set on the stereoscopic marker device on the spinal spike, and thus the six DOF attitude data (i.e., position data) of the stereoscopic marker device can be calculated when the six DOF photographic devices shoot one primary marker or three secondary markers of the polyhedral cube. 
     Second, the concept of primary and secondary markers is introduced to the stereoscopic marker device of the present disclosure. When the primary marker is obscured, spatial coordinate information of the primary marker is calculated in real time by peripheral secondary markers, to ensure that precise positioning of surgical site is not affected when medical workers or other objects obscure the stereoscopic marker device. 
     Third, the stereoscopic marker device of the present disclosure has a QR code feature, image recognition can be improved, and image capturing efficiency of the six DOF photographic devices is further improved. 
     Fourth, the present disclosure develops the stereoscopic marker device having a QR code feature by using a special material, and three-dimensional spatial coordinate information can be defined by a single stereoscopic marker device. 
     Fifth, the three-dimensional real-time positioning method of orthopedic surgery of the present disclosure can be applied to a surgery navigation system. Signals of the surgery navigation system cannot be interfered when the stereoscopic marker device of the present disclosure is obscured by medical workers or other objects, thereby increasing the movable position of medical workers or other objects in an operating room, and reducing restriction on the movement of the medical workers in the operating room. 
     In conclusion, it is only a description of preferred implementations or embodiments of the technical means adopted by the present disclosure to resolve the problem, and is not intended to limit the scope of patent implementation of the present disclosure. That is, all variations and modifications that are consistent with the meaning of the scope of the claims of the present disclosure, or made according to the scope of the claims of the present disclosure, are covered by the scope of the claims of the present disclosure.