External Fixation Adjustment Planning From Distortion-Corrected 3D Imaging
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Solution Overview
Problem
Existing external fixation devices, such as hexapods, require manual and time-consuming strut adjustments for precise bone segment placement, and existing adjustment prescription methods fail to account for image distortion and unknown vantage points in radiographic images.
Innovation Solution
A method and system for determining a user-customizable and controllable adjustment prescription for external fixation devices, which corrects image distortion and utilizes radiographic images from unknown or inaccurately identified vantage points by creating a virtual manipulatable three-dimensional model based on fiducial markers and anatomical structure axes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If automated computer-based systems generate adjustment prescriptions using radiographic images, then productivity is improved, but measurement precision deteriorates due to image distortion and unknown vantage points
Solution Approach 1:
The patent introduces a calibration object with known geometry as an intermediary between the radiographic imaging system and the bone segments. This calibration object serves as a reference mediator that enables the automated system to compensate for image distortion and determine accurate vantage points, thereby maintaining measurement precision while preserving productivity benefits
Solution Approach 2:
The system dynamically adjusts imaging parameters by capturing radiographic images at multiple different vantage points and orientations. By changing the parameters of the imaging process (position, angle, orientation) and using the calibration object to characterize these changes, the system can computationally correct for distortion and achieve accurate bone segment placement measurements
2Measurement precision
If manual incremental adjustment of struts is performed, then measurement precision is maintained, but productivity deteriorates due to time-consuming incremental adjustments
Solution Approach 1:
The system performs preliminary actions by capturing multiple radiographic images at different vantage points and using the calibration object to pre-calculate the complete adjustment prescription before actual bone segment manipulation. This preliminary computational work enables direct implementation of accurate adjustments without time-consuming incremental trial-and-error procedures
3Ease of operation
If radiographic images are used for modeling, then ease of operation is improved, but measurement precision deteriorates due to image distortion
Solution Approach 1:
The calibration object acts as an intermediary reference that bridges the distorted radiographic images and the accurate 3D model. By using the known geometry of the calibration object visible in the images, the system can computationally correct for distortion and accurately identify fiducial marker positions, maintaining both ease of operation and measurement precision
Data Source
AI summary
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.