RU2588316C2 - Orthopedic fixation with imagery analysis - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medical equipment, namely to devices for analysis of images during dental fixation. Computer-readable data medium has computer-readable instructions which, when executed by one or more processors, execute method of orthopaedic fixation images analysing, which contains capture one or more image generators, first and second 2D images of fixation device and first and second segments of bone, attached to it, first image is captured from first orientation, and second image captured from second orientation, different from first orientation , obtaining plurality of parameters of scene image formation based on comparison of identified corresponding location of multiple elements of retainer in first and second two-dimensional images with appropriate locations multiple elements of retainer in three-dimensional space, at retainer contain components of fixation device. Obtaining plurality of parameters of scene images generation comprises identification of appropriate location of multiple elements of retainer in first and second two-dimensional images, first and second transformation matrices corresponding to first and second two-dimensional images using identified corresponding location of multiple elements of retainer, and decomposition of transformation matrices into plurality of parameters of scene images generation. After that, restoring 3D representation of first and second segments bone relative to fixation device is performed on basis of plurality of parameters of image forming scene. In second version of computer-readable data medium processors method is executed comprising preliminary production of first and second 2D images of fixation device and first and second segments of bone, attached to it, first image is captured from orientation, and second image is captured of second orientation, different from first orientation, set of parameters of scene image formation based on comparison of identified corresponding location of multiple elements of retainer in first and second two-dimensional images with appropriate locations multiple elements of retainer in three-dimensional space. At that multiple elements of retainer contain components of fixation device. At that, multiple parameters of scene images generation comprises identification of appropriate location of multiple elements of retainer in first and second two-dimensional images, first and second transformation matrices and decomposition of transformation matrices on parameters of scene image forming apparatus, and recovery of 3D representation of first and second segments bone relative to fixation device on basis of plurality of parameters of image forming scene.

EFFECT: using invention allows to expanded range of technical means of image analysis in orthopaedic fixation.

17 cl, 3 dwg

Description

Cross reference to related applications

This patent application claims the priority of UK patent application No. GB 1008281.6, filed May 19, 2010, which is hereby incorporated by reference in its entirety.

State of the art

The methods used in the treatment of bone fractures and / or bone deformations may include the use of external fixators, such as fixative frames, which are surgically mounted on bone segments on opposite sides of the fracture site. A pair of X-ray images of the fixative and bone segments at the fracture site are removed. As a rule, x-ray images should be orthogonal or perpendicular to each other and aligned with the anatomical axes of the patient. Image data is then processed using orthogonal projection methods to construct a three-dimensional representation of the fixative and bone segments, which can be used to develop a treatment plan, which may, for example, include alignment of bone segments by means of adjustments of the fixative.

However, the possibility of obtaining orthogonal x-ray images of the fracture site may be limited by factors beyond the control of the surgeon, for example, the maneuverability of the imaging device, the anatomical location of the fracture or deformation, and / or pain experienced by the patient when the broken limb is positioned to form orthogonal images. Such as these limiting factors may introduce inaccuracies in the imaging process. These inaccuracies can have undesirable consequences, such as improper alignment of bone segments during the treatment process, jeopardizing the fusion of bone segments, the need for additional x-ray imaging cycles to facilitate alignment corrections, or even the need for additional surgical operations.

SUMMARY OF THE INVENTION

In accordance with one embodiment, the orthopedic fixation method comprises attaching a fixation device to the first and second bone segments. The method further comprises capturing a first image of the fixation device and bone segments from a first orientation relative to the fixation device. The method further further comprises capturing a second image of the fixation device and bone segments from a second orientation relative to the fixation device, which is different from the first orientation. The method further further comprises computing the first and second transformation matrices for the first and second images, respectively. The method further further comprises using transformation matrices to reconstruct a three-dimensional representation of the first and second bone segments relative to the fixation device.

According to an alternative embodiment, a computer-readable storage medium has instructions stored on it and read by a computer, which, when executed by a processor, perform a method for analyzing orthopedic fixation images. The method comprises capturing the first and second images of the fixation device and the first and second bone segments attached to it by means of an image forming device. The first image is captured from the first orientation and the second image is captured from a second orientation different from the first orientation. The method further comprises obtaining a plurality of image acquisition scene parameters. The method further further comprises reconstructing a three-dimensional representation of the first and second bone segments relative to the fixation device, based on the plurality of parameters of the image acquisition scenes.

Brief Description of the Drawings

The foregoing description of the invention, as well as the following detailed description of preferred embodiments of the application, will be better understood when reading in conjunction with the attached drawings. For the purpose of illustrating methods and / or technologies of orthopedic fixation with image analysis, preferred embodiments are shown in the drawings. However, it should be understood that the application currently under consideration is not limited to the specific layouts and / or tools shown in the drawings, in which:

FIG. 1 is a perspective view of a fixing assembly disposed for imaging in accordance with an embodiment;

FIG. 2 is a perspective view of an example of an image forming process by the fixing assembly shown in FIG. one; and

FIG. 3 is a flowchart of an example of orthopedic fixation with an image analysis process in accordance with an embodiment.

Detailed description

For convenience, the same or equivalent elements in the various embodiments shown in the drawings are denoted by the same reference numerals. Some terminology is used in the following description for convenience only and is not a limitation. The words “right,” “left,” “upper,” and “lower” indicate directions in the referenced drawings. The words "in", "inside", "out" and "outside" refer to directions, respectively, to the geometric center of the device and its specific parts and to directions from them. Terminology not intended to create restrictions contains the words listed above, their derivatives, and words of a similar meaning.

Turning first to FIG. 1, body tissues, for example, the first and second bone segments 102, 104 can be aligned and / or oriented so as to stimulate fusion or other healing between body tissues. Alignment and / or orientation of body tissue can be achieved by attaching body tissue to an adjustable fixation device, such as an orthopedic fixator 100. The orthopedic fixator can include an external fixation device that contains many discrete fixation elements that remain external to the patient's body, but which are attached to the corresponding individual tissues of the body, for example, using minimally invasive fasteners. By adjusting the spatial arrangement of the fixative elements relative to each other, the corresponding body tissues attached to it can be reoriented and / or otherwise aligned with each other, for example, to stimulate splicing between body tissues during the treatment process. The use of external orthopedic fixators in combination with the image analysis and location technologies described here may be preferred in applications where direct measurement and manipulation of body tissues is not possible when limited or minimally invasive access to body tissues or the like is desired.

The elements of the latch can be connected to each other through the adjustment elements, and the adjustment elements are configured to facilitate changing the spatial arrangement of the elements of the latch relative to each other. For example, in the embodiment shown, the orthopedic retainer 100 comprises a pair of retainer elements in the form of an upper retainer ring 106 and a lower retainer ring 108. The retainer rings 106, 108 may be constructed the same or differently. For example, retainer rings 106, 108 may have diameters that are the same or different. Similarly, retainer rings 106, 108 can be designed with variable cross-section diameters, thickness, etc. It should be understood that the retainer elements for the orthopedic retainer 100 are not limited to the upper and lower retainer rings 106, 108 shown in the drawings and that the orthopedic retainer 100 may have an alternative design. For example, additional retainer rings may be provided and they may be coupled to retainer ring 106 and / or 108. Additionally, it should be understood that the configuration of the retainer elements is not limited to rings, and that at least one, such as the one described above, the retainer element can be constructed alternatively using any other suitable geometry.

The first and second bone segments 102, 104 can be rigidly attached to the upper and lower retainer rings 106, 108, respectively, using fasteners that can be mounted on the retainer rings 106, 108. For example, in the embodiment shown, fasteners are provided in the form of fastening rods 110 and fastening wires 112.

The rods 110 and wires 112 extend between the proximal ends attached to the mounting elements 114, which are mounted on the retainer rings 106, 108, and the opposite distal ends, which are inserted into the bone segments 102, 104 or otherwise attached to the bone segments 102, 104 . The mounting elements 114 can be removably mounted on the retainer rings 106, 108 at predetermined points along the circumference of the retainer rings 106, 108, for example, by inserting them into threaded holes defined by the retainer rings. For each retainer ring 106, 108, mounting elements 114 may be mounted on the upper surface of the ring, the lower surface of the ring, or any combination thereof. It should be noted that the fasteners are not limited to the configuration of the illustrated embodiment. For example, any number of fasteners, such as shafts 110 and wires 112 and any others, can be used to attach bone segments to the corresponding retainer elements in accordance with the requirements. Additionally, it should be understood that one or more fasteners, for example, rods 110 and / or wires 112, can alternatively be configured to be mounted directly onto the retainer rings 106, 108 without using the mounting elements 114.

The upper and lower retainer rings 106, 108 may be connected to each other by at least one of a plurality of adjustment elements. At least one, such as described above, the adjustment element may be configured to adjust the spatial arrangement of the retainer rings relative to each other. For example, in the shown embodiment, the upper and lower retainer rings 106, 108 are connected to each other by a plurality of adjustment elements provided in the form of length-adjustable uprights 116. It should be understood that the design of the orthopedic retainer 100 is not limited to six uprights 116, as in the shown embodiment implementation, and that more or less racks may be used as necessary.

Each of the length-adjustable uprights 116 may include oppositely directed upper and lower rack fragments 118, 120. Each of the upper and lower fragments 118, 120 of the strut have proximal ends placed in the connecting element or sleeve 122 and opposite distal ends connected to universal joints 124 mounted on the upper and lower retainer rings 106, 108, respectively. Universal joints in the shown embodiment are arranged in pairs that are uniformly spatially spaced along the circumference of the upper and lower retainer rings 106, 108, but can alternatively be placed in any other places on the retainer rings, as necessary.

The proximal ends of the upper and lower fragments 118, 120 of the uprights for each rack 116 may have threads on them that can be received by the complementary thread of the sleeve 122, so that when the proximal ends of the upper and lower fragments 118, 120 of the rack 116 are received in the corresponding sleeve 122, the rotation of the sleeve 122 causes the upper and lower fragments 118, 120 of the rack to move translationally inside the sleeve 122, thereby causing the rack 116 to lengthen or shorten, depending on the direction of rotation. Thus, the length of each rack 116 can be independently adjusted relative to the remaining racks. It should be understood that the adjustment elements are not limited to length-adjustable uprights 116, as in the shown embodiment, and that the adjustment elements can be constructed alternatively, depending on the need, using, for example, one or more alternative configurations, alternative length adjustment mechanisms, etc. P.

Length-adjustable struts 116 and universal joints 124, by means of which they are mounted on the upper and lower retainer rings 106, 108, allow the orthopedic retainer 100 to function like a Stuart platform and, more specifically, like an annular osteogenesis system with traction, hexapod or Taylor spatial frame. That is, by adjusting the length of the uprights 116, it is possible to change the spatial arrangement of the upper and lower retainer rings 106, 108 and, thus, bone segments 102, 104. For example, in the embodiment shown, the first bone segment 102 is attached to the upper retainer ring 106, and the second bone segment 104 is attached to the lower retainer ring 108. It should be understood that the fastening of the first and second bone segments 102, 104 to the upper and lower retainer rings 106, 108 is not limited to the embodiment shown in the drawing (for example, when the central longitudinal axes L1, L2 of the first and second bone segments 102, 104 are essentially perpendicular to the corresponding planes of the upper and lower retainer rings 106, 108), and that the surgeon has complete freedom to align the first and second bone segments 102, 104 inside the upper and lower retainer rings 106, 108 during orthopedic configuration whose latch is 100.

By changing the length of one or more struts 116, the location of the upper and lower retainer rings 106, 108, and thus the bone segments 102, and 104, relative to each other can be changed so that their respective longitudinal axes L1, L2 are substantially aligned with each other and so that their respective broken ends 103, 105 (bones) fit together, stimulating splicing during the healing process. It should be understood that the adjustment of the uprights 116 is not limited to the adjustment of the length as described herein, and that the uprights 116 can be adjusted differently as necessary. Additionally, it should be understood that the adjustment of the positions of the locking elements is not limited to the adjustment of the struts 116 with adjustable length and that the location of the locking elements relative to each other can be adjusted in an alternative way, for example, in accordance with the type and / or number of adjustment elements connected to the locking device.

Changing the position of the fixation elements of an orthopedic fixation device, such as orthopedic fixation 100, can be used to correct the wrong position during angular curvature, longitudinal movement, rotation, or any combination thereof inside body tissues. A fixation device, such as an orthopedic fixator 100, used using the techniques described here, can correct many of these defects in the wrong position individually or simultaneously. However, it should be understood that the fixation device is not limited to the orthopedic fixator 100 shown in the drawings, and that the fixation device can alternatively be designed as necessary. For example, the locking device may contain additional locking elements, may contain locking elements having alternative configurations, may contain more or less adjustment elements, may contain alternatively designed adjustment elements, or any combination thereof.

In FIG. 2-3, an example of orthopedic fixation with an image analysis process or a method according to an embodiment is shown. The steps for performing an orthopedic fixation example with image analysis method 300 are shown in the flowchart of FIG. 3. At 302, body tissues such as the first and second bone segments 102, 104 can be connected to an adjustable fixation device, such as an orthopedic fixator 100, as described above.

At step 304, using an orthopedic fixator 100 fixed to the bone segments 102, 104, at least one of the plurality of images of the fixative 100 and bone segments 102, 104 can be removed. Images can be captured using the same or different imaging techniques. For example, images can be obtained using radiography, computed tomography, magnetic resonance imaging, ultrasound, infrared imaging, photography, fluoroscopy, visual spectroscopic imaging, or any combination thereof.

Images can be captured from any position and / or orientation relative to each other and relative to the retainer 100 and bone segments 102, 104. In other words, there is no requirement that the captured images be orthogonal to each other or aligned with the patient’s anatomical axes, thus providing the surgeon with almost complete freedom of action when positioning the imaging devices 130. Preferably, the images 126, 128 are captured from various directions or orientations so that the images do not overlap. For example, in the embodiment of the image plane shown in the drawing, the image pairs 126, 128 are not perpendicular to each other. In other words, the angle α between the image planes of the images 126, 128 is not 90 degrees, so that the images 126, 128 are non-orthogonal with respect to each other. Preferably, at least two images are captured, although capturing additional images can increase the accuracy of the method.

Images 126, 128 may be captured using one or more image forming sources or image forming devices, for example, x-ray image forming devices 130 and / or corresponding image forming devices 127, 129. Images 126, 128 may be X-ray images captured by a single movable X-ray image forming apparatus 130, or may be captured by separately located image forming devices 130. Preferably, the position of the image pickup devices 127, 129 and / or image forming devices 130 with respect to the spatial origin 135 of the three-dimensional space coordinates described in more detail below is known. The position of the imaging devices 130 can be manually set and / or oriented under the control of a surgeon, set automatically, for example, by a programmable imaging device or any combination thereof.

At step 306, image forming scene parameters related to the latch 100, bone segments 102, 104, image forming device (s) 130, and image capturing devices 127, 129 are obtained. The parameters of the imaging scene can be used to construct a three-dimensional representation of the location of the bone segments 102, 104 in the retainer 100, as described in more detail below. One or more image forming scene parameters may be known. Parameters of the imaging scene that are not known can be obtained, for example, by mathematically comparing the locations of the representations of the elements of the latch in the two-dimensional space of x-ray images 126, 128 with the three-dimensional locations of these elements on the geometry of the latch 100. In a preferred embodiment, the parameters of the scene of the imaging calculated using a pinhole or perspective camera models. For example, the parameters of the imaging scene can be determined numerically using matrix algebra, as described in more detail below.

The parameters of the image formation scene may, in particular, include scaled pixel coefficients of the image, aspect ratio of the image pixels, bevel coefficient of the image sensor, image size, focal length, position and orientation of the image forming source, position of the main point (defined as a point on the plane of the corresponding image 126 128, which is closest to the corresponding image forming apparatus 130), the position and orientation of the elements of the latch 100, the floor The life and orientation of the corresponding image pickup device and the position and orientation of the lens of the image forming source.

In a preferred embodiment, at least some, such as all the parameters of the image forming scene, can be obtained by comparing the representations of specific components or elements of the latch from the latch 100 within the two-dimensional image spaces 126, 128 with the corresponding locations of the same latch elements in real three-dimensional space. The retainer elements comprise components of an orthopedic fixator 100 and are preferably components that can be easily identified in images 126, 128. Points, lines, conical sections, and the like. or any combination thereof can be used to describe the respective configurations of the locking elements. For example, the representations of the fixture elements used in the comparison may include the centerlines of one or more length-adjustable uprights 116, the center points of the universal joints 124, the central points of the mounting elements 114, and the like.

The elements of the latch may additionally contain marker elements that are different from the above components of the latch 100. The elements of the marker can be used when comparing as an addition or instead of using the components of the latch 100. The elements of the marker can be installed in specific places of the components of the latch 100 before imaging, can be embedded inside retainer components 100, or be used in any combination thereof. Marker elements can be made for improved distinguishability in images 126, 128 when compared with the distinguishability of other components of the latch 100. For example, marker elements can be created from various materials, such as radially opaque material, or can be created with configurations that easily distinguish them from other components of the latch 100 in the images 126, 128. In an embodiment, as an example, marker elements may have assigned configurations that correspond to their respective locations on a fixed 100 e.

At 306A, the latch elements can be identified for use in the comparison. Identification of retainer elements and determination of their respective locations can be performed by the surgeon, using software, or in any combination thereof.

The locations of the retainer elements in the two-dimensional image space 126, 128 are determined relative to the local origin 125 of coordinates defined in the imaging planes 126, 128. The local origin 125 of coordinates serve as “zero points” for determining the locations of the retainer elements in the images 126, 128. The locations of the retainer elements can be determined by their respective x and y coordinates relative to the corresponding local origin of 125 coordinates. The location of the local origin 125 of the coordinates within the corresponding image can be arbitrary while it is in the image plane. Typically, the origin is located in the center of the image or in the corner of the image, such as the bottom left corner. It should be understood that the locations of the local coordinates are not limited to the shown local coordinates 125 and that the local coordinates 125 can alternatively be defined in any other places. Additionally, it should be understood that the location of the local origin 125 coordinates can be determined by the surgeon, using software or any combination thereof.

At step 306B, a corresponding transformation matrix P can be computed for each of the images 126, 128. The transformation matrices can be used to map the location coordinates of the map of one or more corresponding latch elements in real three-dimensional space to the corresponding coordinates of the latch element (s) in two-dimensional the space of the corresponding image 126, 128. It should be understood that the same fixation element (s) should not be used when comparing two images 126, 128. N For example, the latch element used in constructing the transformation matrix associated with image 126 may be the same or different from the latch element used in constructing the transformation matrix associated with image 128. Additionally, it should be understood that increasing the number of latch elements used when computing transformation matrices, can increase the accuracy of the method. This operation is represented by the following equation:

(1) $$\left[\begin{array}{c}x\\ y\\ \mathrm{one}\end{array}\right]=P\cdot \left[\begin{array}{c}X\\ Y\\ Z\\ \mathrm{one}\end{array}\right]$$

(one)

The x and y symbols represent the coordinates of the location relative to the local origin 125 of the coordinates of the fixer element point in the two-dimensional image space 126, 128. The X, Y and Z symbols represent the corresponding coordinates of the location relative to the spatial origin of the 135 coordinate coordinates of the fixer element point in real three-dimensional space. In the embodiment shown in the drawing, the point corresponding to the center of the plane defined by the upper surface of the upper retainer ring 106 is defined as the spatial origin 135 of the coordinates. The matrix P shown may have at least four elements in width and three elements in height. In a preferred embodiment, the elements of the matrix P can be calculated by solving the following matrix equation:

A p = B (2)

The vector p may contain eleven elements representing the values of the matrix P. The following equations represent the arrangements of elements in the vector p and the matrix P:

p = [p ₁ p ₂ p ₃ p ₄ p ₅ p ₆ p ₇ p ₈ p ₉ p ₁₀ p ₁₁ ] ^T (3)

(4) $$P=\left[\begin{array}{c}{p}_{\mathrm{one}}\\ p_5\\ p_9\end{array}\begin{array}{ccc}{p}_2& p_3& p_{\mathrm{four}}\\ p_6& p_7& p_8\\ p_{10}& p_{\mathrm{eleven}}& p_{12}\end{array}\right]$$

(four)

In a preferred embodiment, for the twelfth element p _{12 of the} matrix P, a numerical value of one can be set. Matrices A and B can be collected using two-dimensional and three-dimensional information of the elements of the latch. For each point representing the corresponding latch element, two rows of matrices A and B can be created. The following equation represents the values of two rows added to the matrices A and B for each point of the latch element (for example, the center point of the corresponding universal joint 124):

(5) $$\left[\begin{array}{cccc}\mathrm{...}& \mathrm{...}& \mathrm{...}& \mathrm{...}\\ X& Y& Z& \mathrm{one}\\ & & & \\ \mathrm{...}& \mathrm{...}& \mathrm{...}& \mathrm{...}\end{array}\begin{array}{cccc}\mathrm{...}& \mathrm{...}& \mathrm{...}& \mathrm{...}\\ 0& 0& 0& 0\\ & & & \\ \mathrm{...}& \mathrm{...}& \mathrm{...}& \mathrm{...}\end{array}.\begin{array}{c}\mathrm{...}\\ -x\cdot X\\ -y\cdot X\\ \mathrm{...}\end{array}\begin{array}{c}\mathrm{...}\\ -x\cdot Y\\ -y\cdot Y\\ \mathrm{...}\end{array}\begin{array}{c}\mathrm{...}\\ -x\cdot Z\\ -y\cdot Z\\ \mathrm{...}\end{array}\right]\cdot p=\left[\begin{array}{c}\mathrm{...}\\ x\\ y\\ \mathrm{...}\end{array}\right]$$

(5)

The symbols X, Y, and Z represent the local coordinates of the point of the latch element in real three-dimensional space relative to the spatial origin of the 135 coordinates, and the symbols x and y represent the local coordinates of the location corresponding to the point of the latch element in the two-dimensional space of the corresponding image 126, 128 relative to the local origin 125 coordinates.

For each line representing the corresponding latch element, two rows of matrices A and B can be created. The following equation represents the values of two rows added to the matrices A and B for each line of the latch element (for example, the center line of the corresponding rack 116 adjustable in length):

(6) $$\left[\begin{array}{cccc}\mathrm{...}& \mathrm{...}& \mathrm{...}& \mathrm{...}\\ X\cdot a& Y\cdot a& Z\cdot a& a\\ dX\cdot a& dY\cdot a& dZ\cdot a& 0\\ \mathrm{...}& \mathrm{...}& \mathrm{...}& \mathrm{...}\end{array}\begin{array}{cccc}\mathrm{...}& \mathrm{...}& \mathrm{...}& \mathrm{...}\\ X\cdot b& Y\cdot b& Z\cdot b& b\\ dX\cdot b& dY\cdot b& dZX\cdot b& 0\\ \mathrm{...}& \mathrm{...}& \mathrm{...}& \mathrm{...}\end{array}.\begin{array}{c}\mathrm{...}\\ X\cdot c\\ dX\cdot c\\ \mathrm{...}\end{array}\begin{array}{c}\mathrm{...}\\ Y\cdot c\\ dY\cdot c\\ \mathrm{...}\end{array}\begin{array}{c}\mathrm{...}\\ Z\cdot c\\ dZ\cdot c\\ \mathrm{...}\end{array}\right]\cdot p=\left[\begin{array}{c}\mathrm{...}\\ -c\\ 0\\ \mathrm{...}\end{array}\right]$$

(6)

The symbols X, Y, and Z represent the coordinate values of the location of the point belonging to the line of the fixture element in real three-dimensional space relative to the spatial origin 135 of the coordinates. The symbols dX, dY and dZ represent the values of the line gradient in real three-dimensional space. Symbols a, b and c represent constants defining a line in the two-dimensional space of the corresponding image 126, 128. For example, a, b and c can be calculated using two points belonging to the line in the corresponding image 126, 128. In a preferred embodiment, the value of b assumed to be 1 if the line is not a vertical line when the value of b is zero. The correlation of the constants a, b, and c with the corresponding coordinates x and y of the image is represented by the following equation:

a x + b y + c = 0 (7)

Equation (2) can be further limited by the use of six or more fixation elements, for example, adjustable along the length of the uprights 116. It should be understood that it is not necessary for all the fixation elements to be visible in one of the images 126, 128 in order to obtain the matrix P. Additionally, understand that if one or more of the above image forming scene parameters is known, known parameters can be used to reduce the minimum number of locking elements required to limit equations (2). For example, such information can be obtained from modern imaging systems in DICOM image headers. Preferably, the special value decomposition or the least squares method can be used to solve equation (2) for the values of the vector p.

At step 306C, the transformation matrices may be decomposed into image formation scene parameters. The following equation can be used to relate matrix P to matrices E and I:

P = I · E (8)

It should be understood that, by analyzing the matrix P, additional conditions can be introduced. For example, the method presented by Tsai described in "A Versatile Camera Calibration Technique for High-Accuracy 3D Machine Vision Metrology Using of-the-shelf TV Cameras and Lenses", IEEE Journal of Robotics & Automation, RA-3, No. 4, 323-344, August 1987, which is incorporated herein by reference in its entirety, may be used to correct images 126, 128 with radial curvature.

Matrices E and I contain the parameters of the imaging scene. The following equation represents the composition of matrix I:

(9) $$I=\left[\begin{array}{ccc}sx& 0& -tx\\ 0& sy& -ty\\ 0& 0& \mathrm{one}/f\end{array}\right]$$

(9)

Symbols sx and sy represent the values of the scale factors of the image coordinates (for example, pixel scale factors). The symbol f representing the focal length corresponds to the value of the shortest distance between the corresponding image forming source 130 and the plane of the corresponding image 126, 128. The symbols tx and ty represent the coordinates of the base point relative to the local origin 125 of the coordinates of the corresponding image 126, 128. The following equation represents the matrix composition E:

(10) $$E=\left[\begin{array}{c}{r}_{\mathrm{one}}\\ r_{\mathrm{four}}\\ r_7\end{array}\begin{array}{c}{r}_2\\ r_5\\ r_8\end{array}\begin{array}{c}{r}_3\\ r_6\\ r_9\end{array}\begin{array}{c}-(r_{\mathrm{one}}\cdot o_x+r_2\cdot o_y+r_3\cdot o_z)\\ -(r_{\mathrm{four}}\cdot o_x+r_5\cdot o_y+r_6\cdot o_z)\\ -(r_7\cdot o_x+r_8\cdot o_y+r_9\cdot o_z)\end{array}\begin{array}{c}\\ \\ \end{array}\right]$$

(10)

The symbols o _x , o _y and o _z represent the position values of the latch 100 in real three-dimensional space. The symbols r ₁ -r ₉ describe the orientation of the latch 100. These values can be collected in a three-dimensional rotational matrix R, represented by the following equation:

(11) $$R=\left[\begin{array}{ccc}{r}_{\mathrm{one}}& r_2& r_3\\ r_{\mathrm{four}}& r_5& r_6\\ r_7& r_8& r_9\end{array}\right]$$

(eleven)

The Trucco and Verri methods described in Introductory Techniques of 3-D Computer Vision, Prentice Hall, 1998, or the method of Hartley as described in Euclidian Reconstruction from Uncalibrated Views, Applications of Invariance in Computer Vision, pages 237 -256, Springer Verlag, Berlin Heidelberg, 1994, which are contained in their entirety, can be used to obtain the values of E and / or I. Using the resulting values of the matrices E and I, the full three-dimensional scene of the latch 100 and segments 102 can be reconstructed 104 bones.

For example, in FIG. 2 shows an example of a three-dimensional image acquisition scene reconstructed from x-ray images 126, 128. In the shown embodiment, x-ray radiation is provided by x-ray image forming devices 130. It should be understood that the x-ray imaging devices 130 may be the same or other imaging devices as described above. The x-rays emitted by the image forming apparatuses 130 are received by the respective image forming apparatuses, thereby capturing images 126, 128. Preferably, the arrangement of the image forming apparatuses 130 relative to the local origin 125 is known.

At step 308, the images 126, 128 and the parameters of the imaging scene can be used to obtain the position and / or orientation of the bone segments 102, 104 in three-dimensional space. The obtained position and / or orientation data can be used to develop a patient treatment plan, for example, changing the orientation and / or position of the broken first and second bone segments 102, 104 to stimulate fusion between bone segments 102, 104, as described in more detail below. It should be understood that the methods and technologies of orthopedic fixation with image analysis described here are not limited to applying broken bones to repositioning and that orthopedic fixation with image analysis can be used in any other type of fixation procedure, as necessary, for example, to lengthen bones, correction of anatomical defects, etc.

At step 308A, bone elements containing representations of specific areas (e.g., anatomical features) of bone segments 102, 104 can be identified and their locations within images 126, 128 can be determined. Preferably, the locations of the bone elements are determined relative to the corresponding local origin 125 of the image coordinates 126, 128. The identification of the bone elements and determination of their corresponding locations can be performed by the surgeon, using software or any combination thereof.

Bone elements can be used to construct a three-dimensional representation of the position and / or orientation of bone segments 102, 104. Preferably, bone elements are easily identified in images 126, 128. Points, lines, conical sections, etc., or any combination thereof, can be used to describe the corresponding configurations of bone elements. For example, in the embodiment shown, points 134 and 136 representing broken ends 103, 105 of bone segments 102, 104, respectively, are identified as bone elements in images 126, 128.

Bone elements may further comprise marker elements that are implanted into bone segments 102, 104 before imaging. Marker elements can be used to complement or instead of the bone elements described above identified in images 124, 126. The marker elements can be made with improved distinguishability in images 126, 128, when compared with the distinguishability of the anatomical features of bone segments 102, 104. For example, marker elements can be created from an opaque material for x-ray radiation or can be created with easily distinguishable configurations.

At step 308B, a three-dimensional representation of 200 bone segments 102, 104 can be reconstructed. A three-dimensional representation may be created with or without the corresponding representation of the latch 100. In the shown embodiment, pairs of emission lines, such as emission lines 138, 140 and 142, 144, can be created for points of bone elements 134, 136, respectively. Each radiation line connects a bone element in one of the images 126, 128 with a corresponding imaging device 130. Each pair of emission lines can be analyzed for a common intersection point, such as points 146, 148. The common intersection points 146, 148 represent the corresponding positions of the points of the bone elements 134, 136 in a three-dimensional representation of the bone segments 102, 104. Of course, more than a pair of ray lines can be constructed, namely, many, for example, if more than two images are captured. If the ray lines of a particular set do not intersect, the point closest to all ray lines in the set can be used as a common intersection point.

The positions and / or orientations of the bone segments 102, 104 can be quantified or measured using common intersection points, for example, points 146, 148. For example, lines representing the axial lines of the bone segments 102, 104 can be created and compared with the anatomical axes the patient. Additionally, the distances between the broken ends 103, 105 of the bone segments 102, 104 can be quantified. Using these or similar methods, the positions and / or orientations of bone segments 102, 104 can be determined.

At step 310, the three-dimensional representation 200 can be used to determine the required changes in the positions and / or orientations of the bone segments 102, 104, for example, how the position of the bone segments 102, 104 can be changed relative to each other to stimulate splicing between the bone segments 102, 104. For example, in the embodiment shown, it may be necessary to change the angular curvature of the second bone segment 104 so that the axes L1 and L2 are aligned, and to reposition the second bone segment so that the broken ends 103, 105 of the bone segments 102, 104 abut against each other. Preferably, the determination of the desired changes in the positions and / or orientations of the bone segments 102, 104 is done by the surgeon. In an embodiment, as an example, lines representing the longitudinal axes L1, L2 of the first and second bone segments 102, 104 can be created in a three-dimensional view to help determine what changes are required in the positions and / or orientations of the bone segments 102, 104. In determining the desired changes in the positions and / or orientations of the bone segments, the surgeon may be assisted by software such as a computer program configured to determine the required positions and / or orientation of the bone segments 102, 104. Preferably, the desired changes in the positions and / or orientations of the bone segments 102, 104 are determined relative to the spatial origin 135 of the coordinates.

When the required changes in the positions and / or orientations of the bone segments 102, 104 have been determined, a treatment plan can be determined to effect changes in position and / or orientation. In a preferred embodiment, the desired changes in the positions and / or orientations of the bone segments 102, 104 can be made gradually, by a series of smaller changes. The positions and / or orientations of the bone segments 102, 104 may vary by changing the positions and / or orientations of the upper and lower retainer rings 106, 108 relative to each other, for example, by extending or shortening the struts 116 that are adjustable in length.

At step 312, the desired changes in the geometry of the latch 100 (i.e., the position and / or orientation of the latch 100), which can allow the required changes in the positions and / or orientations of the bone segments 102, 104, can be calculated using the matrix algebra described above. For example, desired changes in the position and / or reorientation of the second bone segment 104 relative to the first bone segment 102 can be converted to changes in the position and / or orientation of the lower retainer ring 108 relative to the upper retainer ring 106. The required changes in the geometry of the latch can be expressed relative to the origin of the 145 coordinates of the latch defined for the orthopedic latch 100. It should be understood that the origin of the 145 coordinates of the latch must not coincide with the spatial origin of the 135 coordinates, as can be seen in the shown embodiment.

At 314, a treatment plan can be implemented, according to which the positions and / or orientations of the bone segments 102, 104 can be changed by changing the geometry of the latch 100.

As described above, one or more steps of the method described herein and shown in FIG. 3 may be executed by a computer program, software, firmware, or other form of computer-readable instructions placed on a computer-readable storage medium for execution by a computer or processor. Examples of computer-readable storage media may include computer-readable storage media and computer-readable storage media. Examples of computer-readable storage media are, in particular, read-only memory (ROM), random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard drives and removable drives, magneto-optical media and optical media such as CD-ROMs and digital versatile disks (DVDs). Examples of computer-readable media include, in particular, electronic signals transmitted over wired or wireless connections.

It should be understood that orthopedic fixation using the image analysis technology described here provides not only the use of non-orthogonal images, but also allows the use of overlapping images, images captured using various image forming methods, images captured at various settings, etc., providing Thus, the surgeon has greater freedom of action compared to existing methods of fixing and imaging.

Additionally, it should be understood that the methods and technologies described herein in relation to orthopedic fixation can also be used for other applications. For example, a mechanical manipulation device with the ability to change position, such as a parallel manipulator, a Stuart platform, etc., may have first and second objects attached to it. A manipulation device can be constructed from a variety of components. The first and second objects can be any objects whose position and / or alignment of which relative to each other must be changed. Steps similar to the steps of the method 300 of orthopedic fixation with image analysis can be used to reconstruct a three-dimensional representation of the first and second objects relative to the manipulation device with the possibility of changing position. The three-dimensional representation of the first and second objects can be reconstructed and used to determine one or more changes in the geometry of the manipulation device, which, when implemented, can change the location of the first and second objects relative to each other. The three-dimensional representation can be reconstructed using the corresponding first and second sets of parameters of the image forming scene, determining the location of at least one of the objects in the first image and determining the location of the element of at least one of the objects in the second image.

Although orthopedic fixation methods with image analysis have been described herein with reference to preferred embodiments and / or preferred methods, it should be understood that the words that were used here are words of description and illustration, and not words of limitation, and that the scope is here on the positions relative to each other should vary; the disclosure in question is not intended to be limited by these details, but rather is intended to extend to all structures, methods, and / or applications described here is a method of orthopedic fixation with image analysis. Specialists in the art taking advantage of the principles of the present description can make numerous changes to the method of orthopedic fixation with image analysis described here, and changes can be made without departing from the scope and essence of the disclosure, for example, as shown in the attached claims.

Claims (17)

1. A computer-readable storage medium having computer-readable instructions stored on it, which, when executed by one or more processors, perform an orthopedic fixation image analysis method, the method comprising:
capturing, by one or more imaging devices, the first and second two-dimensional images of the fixation device and the first and second bone segments attached to it, wherein the first image is captured from the first orientation and the second image is captured from the second orientation, which differs from the first orientation;
obtaining a plurality of parameters of the image forming scene by comparing the identified respective locations of the plurality of fixer elements in the first and second two-dimensional images with the corresponding locations of the plurality of fixer elements in three-dimensional space, while the plurality of fixer elements contain components of the fixation device, while obtaining the plurality of parameters of the image forming scene :
identifying the respective locations of the plurality of retainer elements in the first and second two-dimensional images;
constructing the first and second transformation matrices corresponding to the first and second two-dimensional images, respectively, using the identified corresponding locations of the plurality of latch elements; and
decomposition of transformation matrices into many parameters of the image formation scene; and
restoration of a three-dimensional representation of the first and second bone segments relative to the fixation device based on the many parameters of the image formation scene. 2. A computer-readable storage medium according to claim 1, wherein the first and second orientations are not orthogonal with respect to each other. 3. The computer-readable storage medium according to claim 1, wherein the method further comprises identifying corresponding locations of a plurality of bone elements in the first and second two-dimensional images, wherein the bone elements contain anatomical features of the first and second bone segments. 4. The computer-readable storage medium according to claim 3, wherein the three-dimensional representation is further restored based on the corresponding locations of the plurality of bone elements. 5. The computer-readable storage medium according to claim 1, wherein the plurality of latch elements comprises tag elements mounted on or integrated into the components of the latch device. 6. The computer-readable storage medium according to claim 1, wherein the method further comprises calculating geometry changes for the fixation device, wherein the geometry changes represent a change in position of the first and second bone segments with respect to each other, wherein the geometry changes are implemented in order to change the position the first and second bone segments in relation to each other. 7. A method for analyzing orthopedic fixation images, the method comprising:
capturing, by one or more imaging devices, the first and second two-dimensional images of the fixation device and the first and second bone segments attached to it, wherein the first image is captured from the first orientation and the second image is captured from the second orientation, which differs from the first orientation;
obtaining a plurality of parameters of the image forming scene by comparing the identified respective locations of the plurality of fixer elements in the first and second two-dimensional images with the corresponding locations of the plurality of fixer elements in three-dimensional space, while the plurality of fixer elements contain components of the fixation device, while obtaining the plurality of parameters of the image forming scene :
identifying the respective locations of the plurality of retainer elements in the first and second two-dimensional images;
constructing the first and second transformation matrices corresponding to the first and second two-dimensional images, respectively, using the identified corresponding locations of the plurality of latch elements; and
decomposition of transformation matrices into parameters of the image formation scene; and
restoration of a three-dimensional representation of the first and second bone segments relative to the fixation device based on the many parameters of the image formation scene. 8. The method according to claim 7, in which the first and second orientations are not orthogonal with respect to each other. 9. The method according to claim 7, further comprising identifying the corresponding locations of the plurality of bone elements in the first and second two-dimensional images, wherein the bone elements contain anatomical features of the first and second bone segments. 10. The method of claim 9, wherein the three-dimensional representation is further restored based on the corresponding locations of the plurality of bone elements. 11. The method according to claim 7, in which the plurality of latch elements comprises label elements mounted on or integrated into the components of the latch device. 12. The method according to claim 7, further comprising calculating geometry changes for the fixation device, wherein the geometry changes represent a change in position of the first and second bone segments with respect to each other, wherein the geometry changes are implemented in order to change the position of the first and second bone segments in relation to each other. 13. A computer-readable storage medium having computer-readable instructions stored on it, which, when executed by one or more processors, perform an orthopedic fixation image analysis method, the method comprising:
obtaining the first and second two-dimensional images of the fixation device and the first and second bone segments attached to it, wherein the first image is captured from the first orientation, and the second image is captured from the second orientation, which differs from the first orientation;
obtaining a plurality of parameters of the image forming scene by comparing the identified respective locations of the plurality of fixer elements in the first and second two-dimensional images with the corresponding locations of the plurality of fixer elements in three-dimensional space, while the plurality of fixer elements contain components of the fixation device, while obtaining the plurality of parameters of the image forming scene :
identifying the respective locations of the plurality of retainer elements in the first and second two-dimensional images;
constructing the first and second transformation matrices corresponding to the first and second two-dimensional images, respectively, using the identified corresponding locations of the plurality of latch elements; and
decomposition of transformation matrices into parameters of the image formation scene; and
restoration of a three-dimensional representation of the first and second bone segments relative to the fixation device based on the many parameters of the image formation scene. 14. The computer-readable storage medium of claim 13, wherein the first and second orientations are not orthogonal to one another. 15. The computer-readable medium according to claim 13, wherein the method further comprises identifying corresponding locations of a plurality of bone elements in the first and second two-dimensional images, wherein the bone elements contain anatomical features of the first and second bone segments, wherein the three-dimensional representation is further restored based on the corresponding locations many bone elements. 16. The computer-readable storage medium according to claim 13, wherein the plurality of latch elements comprise tag elements mounted on or integrated into the components of the latch device. 17. The computer-readable medium according to claim 13, wherein the method further comprises calculating geometry changes for the fixation device, wherein the geometry changes represent a change in position of the first and second bone segments with respect to each other, wherein the geometry changes are implemented in order to change the position the first and second bone segments in relation to each other.

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