Methods and systems for determining adjustment prescriptions of external fixation devices
The present disclosure provides methods for determining an adjustment prescription of an external fixation device affixed to anatomical structures. The methods include obtaining at least two digital radiographic images of differing orientations of the external fixation device and anatomical structures in an initial arrangement. The methods also include identifying fiducial markers of the external fixation device and an axis of the anatomical structures in the at least two radiographic images. The methods include providing a virtual manipulatable three-dimensional model of the external fixation device and the anatomical structures. The methods include providing an adjustment prescription of strut assemblies of the external fixation device based on a user determined desired arrangement of the anatomical structures that rearranges the anatomical structures from the initial arrangement to the desired arrangement via at least one user selected waypoint. The user determined desired arrangement of the anatomical structures is determined via the three-dimensional model.
1 . A method of determining an adjustment prescription of an external fixation device affixed to anatomical structures comprising bone segments, comprising:
obtaining at least two digital radiographic images of differing orientations of the external fixation device and anatomical structures in an initial arrangement;
identifying fiducial markers of the external fixation device in the at least two radiographic images, wherein identifying fiducial markers of the external fixation device in the at least two radiographic images comprises creating individually scaled digital fiducial markers for each fiducial in the radiographic images by correcting distortion of the radiographic images, wherein correcting distortion of the radiographic images comprises:
determining a first ratio of the summation of the fiducial markers in the radiographic image in pixels the expected summation of a dimension of the actual fiducial markers of the external device to determine a volumetric scale of the radiographic image in pixels per unit of fiducial measure;
determining a second ratio of the pixels per fiducial unit of measure to the expected resolution in pixels per image unit of measure of the radiographic image;
adjusting the volumetric scale of the radiographic image based on the second ratio generating an adjusted volumetric scale;
scaling the radiographic image in accordance with the adjusted volumetric scale generating volume-scaled identified fiducials;
determining individual ratios of dimensions of e volume-scaled identified fiducials to the expected fiducial dimension on an individual fiducial basis; and
utilizing the individual ratios to create the individually scaled digital fiducial markers for each fiducial on the radiographic image;
identifying an axis of the anatomical structures in the at least two radiographic images;
providing a virtual manipulatable three-dimensional model of the external fixation device and the anatomical structures from the identified fiducial markers, the at least two radiographic images and the identified axis of the anatomical structures;
receiving a correction input via the three-dimensional model defining a user determined desired arrangement of the three-dimensional model of the bone segments of the anatomical structures;
receiving a waypoint input defining at least one user selected waypoint that defines an intermediate arrangement of the anatomical structures, wherein the intermediate arrangement of the anatomical structures defines a pathway of the movement of the anatomical structures between the initial arrangement and the user determined desired arrangement; and
providing an adjustment prescription of strut assemblies of the external fixation device based on the user determined desired arrangement of the anatomical structures that rearranges the anatomical structures from the initial arrangement to the desired arrangement via the at least one user selected waypoint, wherein the user determined desired arrangement of the anatomical structures is determined via the three-dimensional model.
2 . The method of claim 1 , wherein the external fixation device is a hexapod type external fixation device.
3 . The method of claim 1 , wherein the method is implemented in a computer system.
4 . The method of claim 1 , wherein the pathway of the movement of the anatomical structures is defined by a plurality of waypoints as a plurality of waypoint inputs.
5 . The method of claim 1 , wherein the anatomical structures are represented by bone segment models and the user defined waypoint identifies the position and orientation of the bone segment models with respect to each other between the initial arrangement and the desired arrangement.
6 . A computer system configured to perform a method, the method comprising:
correcting distortion of a radiographic image of a plurality of fiducial markers of an external fixation device and anatomical structures, comprising:
analyzing the radiographic image to identify the fiducial markers;
determining a calculated summation of a dimension of the fiducial markers identified;
determining a first ratio of the calculated summation of the fiducial markers in the radiographic image in pixels to an expected summation of a corresponding expected fiducial dimension of the actual fiducial markers of the external fixation device to determine a volumetric scale of the radiographic image in pixels per unit of fiducial measure;
determining a second ratio of the pixels per fiducial unit of measure to an expected resolution in pixels per image unit of measure of the radiographic image;
adjusting the volumetric scale of the radiographic image based on the second ratio generating an adjusted volumetric scale;
scaling the radiographic image in accordance with the adjusted volumetric scale generating volume-scaled identified fiducials;
determining individual ratios of dimensions of the volume-scaled identified fiducials to the expected fiducial dimension on an individual fiducial basis; and
utilizing the individual ratios of each of the fiducial markers to generate individually scaled digital fiducial markers for each of the fiducial markers identified.
7 . A method of correcting distortion of a radiographic image of a plurality of fiducial markers of an external fixation device and anatomical structures, comprising:
analyzing the radiographic image to identify the fiducial markers;
determining a calculated summation of a dimension of the fiducial markers identified;
determining a first ratio of the calculated summation of the fiducial markers in the radiographic image in pixels to an expected summation of a corresponding expected fiducial dimension of actual fiducial markers of the external fixation device to determine a volumetric scale the radiographic image in pixels per unit of fiducial measure;
determining a second ratio of the pixels per fiducial unit of measure to an expected resolution in pixels per unit of measure of the radiographic image;
adjusting the volumetric scale of the radiographic image based on the second ratio generating an adjusted volumetric scale;
scaling the radiographic image in accordance with the adjusted volumetric scale generating volume-scaled identified fiducials;
determining individual ratios of dimensions of the volume-scaled identified fiducials to the expected fiducial dimension on an individual fiducial basis; and
utilizing the individual ratios of each of the fiducial markers to generate individually scaled digital fiducial markers for each of the fiducial markers identified.
8 . The method of claim 7 , wherein the method is implemented in a computer system.
9 . A computer program product comprising:
a non-transitory computer readable storage medium storing instructions that, when executed by a processor, cause the processor to perform a method of correcting distortion of a radiographic image of a plurality of fiducial markers of an external fixation device and anatomical structures, the method comprising:
analyzing the radiographic image to identify the fiducial markers;
determining a calculated summation of a dimension of the fiducial markers identified;
determining a first ratio of the calculated summation of the fiducial markers in the radiographic image in pixels to an expected summation of a corresponding expected fiducial dimension of actual fiducial markers of the external fixation device to determine a volumetric scale of the radiographic image in pixels per unit of fiducial measure;
determining a second ratio of the pixels per fiducial unit of measure to an expected resolution in pixels per image unit of measure of radiographic image;
adjusting the volumetric scale of the radiographic image based on the second ratio generating an adjusted volumetric scale;
scaling the radiographic image in accordance with the adjusted volumetric scale generating volume-scaled identified fiducials;
determining individual ratios of dimensions of the volume-scaled identified fiducials to the expected fiducial dimension on an individual fiducial basis; and
utilizing the individual ratios of each of the fiducial markers to generate individually scaled digital fiducial markers for each of the fiducial markers identified.
10 . The method according to claim 6 , wherein the scaling of the radiographic image moves the fiducial markers to scaled positions.