Electromagnetic Tracking for Computer-Assisted Surgery
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical tracking in computer-assisted surgery is limited by the requirement for a line of sight between image acquisition devices and optical elements, which can disrupt tracking if the line of sight is obstructed, leading to pauses in orthopedic tracking.
Innovation Solution
A system that continuously emits an electromagnetic field in a surgical volume using electromagnetic sensors on bones and tools, allowing for continuous tracking of position and orientation, and optionally uses an optical waveguide modeling system with multicore optical fibers to provide redundant tracking and alert generation if discrepancies exceed a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If optical tracking is used to track tools and bones, then position and orientation information can be obtained, but tracking is disrupted when line of sight is obstructed
Solution Approach 1:
The patent replaces the optical tracking system with an electromagnetic tracking system. Instead of using optical sensors and retroreflective markers that require line of sight, the system uses electromagnetic fields and sensors to track the position and orientation of tools and bones. This substitution eliminates the line of sight constraint and enables continuous tracking even when optical paths are obstructed by surgical equipment or patient anatomy.
2Reliability
If electromagnetic field is continuously emitted for tracking, then continuous tracking of position and orientation is achieved, but electromagnetic interference may affect other surgical equipment
Solution Approach 1:
The patent employs frequency modulation and specific frequency selection for the electromagnetic field emission. By operating at carefully chosen frequencies and using modulated signals, the system achieves continuous tracking while minimizing interference with other surgical equipment. The electromagnetic sensors detect these modulated signals to determine position and orientation, allowing differentiation between the tracking signals and potential interference.
Solution Approach 2:
The system continuously monitors the electromagnetic field environment and adjusts the emission parameters based on detected interference levels. When interference is detected, the system can modify the frequency or power of the electromagnetic field emission to maintain tracking accuracy while minimizing harmful effects on other equipment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables continuous and accurate tracking of tools and bones during surgery, preventing interruptions due to line-of-sight issues and ensuring precise navigation and positioning, even when optical tracking is obstructed.
Implementation Method 1
continuously emitting an electromagnetic field in a surgical volume incorporating at least one electromagnetic sensor on a bone and/or tool; continuously receiving a signal indicative of a position and/or orientation of the electromagnetic sensor relative to the emitting of electromagnetic field
Data Source
AI summary
There is described a system for tracking at least one tool relative to a bone in computer-assisted surgery. The system generally has a processing unit; and a non-transitory computer-readable memory communicatively coupled to the processing unit and comprising computer-readable program instructions executable by the processing unit for: continuously emitting an electromagnetic field in a surgical volume incorporating at least one electromagnetic sensor on a bone and/or tool; continuously receiving a signal indicative of a position and/or orientation of the electromagnetic sensor relative to the emitting of electromagnetic field; processing the signal to determine the position and/or orientation of the at least one electromagnetic sensor; obtaining geometrical data relating the at least one electromagnetic sensor to the bone and/or tool; and continuously tracking and outputting a first position and/or orientation of the bone and/or tool using the geometrical data and the position and/or orientation of the at least one electromagnetic sensor.