Planar Marker Optical Tracking for Soft Tissue Surgery
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Solution Overview
Problem
Current optical tracking systems for computer-assisted surgery are inadequate due to large and unwieldy locators, limited sterilizability, reduced accuracy in soft tissue surgery, and inability to accurately measure flexible implants and soft tissues, which hinders precise surgical procedures.
Innovation Solution
A medical-technical measuring system incorporating an optical camera system with areal imaging sensors, structured light projection, and high-contrast geometric patterns on flexible or rigid structures that can be sterilized, allowing for accurate tracking and navigation of instruments and body parts, especially in soft tissue surgeries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional optical tracking systems use locators with retro-reflecting spheres, then measurement accuracy is sufficient, but the system becomes large and unwieldy
Solution Approach 1:
The patent extracts the essential tracking function from the complex traditional locator system. Instead of using locators with multiple retro-reflecting spheres, the invention uses a single planar marker with a specific geometric pattern that can be tracked by the camera system, significantly reducing the physical size and complexity of the tracking components while maintaining measurement accuracy
Solution Approach 2:
The patent creates a simplified optical copy of the traditional locator system. The planar marker with geometric pattern serves as an equivalent representation that provides the same tracking information as the complex sphere-based locators, but in a much more compact form that can be integrated into surgical instruments and implants
2Reliability
If traditional locators are used in sterilizable designs, then they can be autoclaved, but the camera system cannot be sterilized
Solution Approach 1:
The patent divides the tracking system into two separable components: the planar marker (which can be sterilized with the surgical instrument) and the camera system (which remains outside the sterile field). This segmentation allows the marker to be autoclaved independently while the camera system operates in the non-sterile environment, eliminating the contradiction
Solution Approach 2:
The planar marker serves as an intermediary element that bridges the sterile and non-sterile environments. It is attached to the surgical instrument or implant in the sterile field, can be sterilized along with it, and yet provides tracking information to the camera system that operates outside the sterile boundary
3Device complexity
If small locators are used for miniaturization, then the system becomes more compact, but measurement accuracy decreases
Solution Approach 1:
The patent enhances the local optical properties of the planar marker by using high-contrast geometric patterns with specific spatial frequencies. This local optimization of the marker's visual characteristics allows the camera system to accurately track even very small markers, achieving sub-millimeter precision with miniaturized components
Solution Approach 2:
The patent transitions from tracking multiple discrete spherical points in 3D space to tracking a 2D planar pattern with rich geometric information. The areal pattern provides multiple reference points and orientation information within a single plane, enabling accurate 6-degree-of-freedom tracking from a compact 2D structure
4Stability of the object's composition
If rigid locators are used, then structural stability is maintained, but they cannot adapt to flexible implants and soft tissues
Solution Approach 1:
The patent employs thin-film planar markers that can be conformally attached to flexible implants and soft tissue surfaces. These thin-film structures maintain their geometric pattern integrity while adapting to the contours of the underlying flexible or deformable surfaces, providing stable tracking references on non-rigid substrates
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
The system provides enhanced measurement accuracy, flexibility, and sterilizability, enabling precise surgical interventions by accurately tracking the position and orientation of instruments and implants, even in complex and soft tissue environments.
Implementation Method 1
a light source (64) integrated into the measuring system (122), which produces structured light (66) projected onto the surface (62) of the object (67) equipped with planar structures (61)
Implementation Method 2
an optical, mobile camera system (63) with optics (65), which measures the spatial orientation and position of areal patterns
Data Source
Figure 1~2b
Figure 2c~3
Figure 4~5
AI summary
The invention relates to a medical measuring system, surgical intervention methods, and the use of a medical measuring system. The measuring system comprises two two-dimensional imaging sensors, a light source that is rigidly connected to the camera system in order to project structured light onto objects, and a structure that has a two-dimensional pattern and is mounted on an object.