Surgical Visualization Using Voxel CSG for Real-Time Resection
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Solution Overview
Problem
Existing methods for visualizing material removal during cut procedures, such as surgical resection, are computationally expensive and often produce inaccurate, artifact-laden representations due to sparse temporal sampling and depth complexity, leading to delays and misrepresentation of resected surfaces.
Innovation Solution
A method utilizing a voxelized constructive solid geometry (CSG) grid and shape sweeping to generate a smooth visual representation of material removal by tracking the cutting tool's positions, applying CSG operations like subtraction, union, and intersection, and employing non-polygonal iso-surface ray marching for efficient real-time updates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional visualization methods are used to track material removal during cut procedures, then real-time surgical guidance is provided, but computational expense increases and visualization delays occur
Solution Approach 1:
The bone model is segmented into a voxel grid where each voxel represents a discrete volumetric element. This segmentation allows the system to track material removal by simply changing the state of individual voxles (from present to removed) rather than performing complex geometric calculations, significantly reducing computational expense while maintaining visualization accuracy.
Solution Approach 2:
A virtual copy of the bone model is created as a voxel grid that mirrors the physical bone's structure. This virtual model allows real-time visualization of material removal through simple voxel state changes without requiring computationally intensive calculations on the actual geometric model, thus improving computational efficiency while preserving visualization fidelity.
2Measurement precision
If traditional visualization methods are used to represent resected surfaces, then material removal is tracked, but visual artifacts such as edgy and ridge-like patterns appear
Solution Approach 1:
By segmenting the bone model into a voxel grid, the representation of resected surfaces becomes inherently smoother. The voxel-based approach naturally fills in gaps and eliminates the edgy, ridge-like artifacts that occur in traditional polygon-based methods, providing a more reliable and artifact-free visualization of the true resected surface geometry.
3Loss of information
If three-dimensional resections are visualized on a two dimensional display, then surgical progress is monitored, but visualization efficiency and clarity decrease
Solution Approach 1:
The patent projects the three-dimensional voxel grid onto a two-dimensional display plane while preserving depth information through clever use of the voxel structure. This allows comprehensive surgical progress monitoring on a 2D screen without requiring complex 3D rendering, reducing visualization complexity while maintaining complete surgical information.
Data Source
AI summary
A method includes providing a bone model and a surgical plan defining a planned implant pose to the bone model, providing, based on the planned implant pose, a planned resection volume and a cut-away object, generating a visualization for surgical navigation by, subtracting, from the bone model, a region of intersection between the bone model and the cut-away object and including a visualization of the planned resection volume, and dynamically updating the visualization of the planned resection volume to show progress in completing a resection by tracking movement of a surgical instrument completing the resection.