Surgical Instrument Keypoint Tracking via Spatiotemporal Graph Attention

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Solution Overview

Problem

Current machine learning models face challenges in accurately tracking multiple surgical instruments due to the complexity of spatial-temporal correlations, especially in robotic-assisted surgery where instruments interact dynamically, leading to imperfect localization and tracking performance.

Innovation Solution

A system utilizing a Spatial-Temporal Graph hierarchy with graph attention and bi-directional temporal encoding, combining spatial and temporal interactions to predict future trajectories of surgical instruments, and refining keypoint detection by integrating spatial and temporal neural networks to account for instrument interactions and future movements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If social-LSTM models are used to track multiple surgical instruments, then the model can capture spatial interactions among instruments, but the model treats all instruments equally and fails to account for hierarchical structures in complex surgical scenarios

Engineering Contradiction:
Improvetracking accuracyVSAvoidmodel complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The model segments the tracking system into two distinct components: a spatial network for detecting keypoint locations in individual frames and a temporal network for predicting trajectories across frames. This segmentation allows each component to specialize, improving overall tracking accuracy while maintaining manageable complexity through modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from purely spatial modeling to spatiotemporal modeling by adding the temporal dimension. The temporal network processes historical trajectory data and predicts future positions, effectively moving the system into a four-dimensional space (x, y, z, t) to capture both spatial relationships and temporal evolution of instrument movements.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If general Multiple Object Tracking models are used, then the system can track multiple instruments, but the models fail to account for dynamic interactions and hierarchical structures specific to surgical procedures

Engineering Contradiction:
Improveadaptability to surgical interactionsVSAvoidkeypoint detection precision
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The model applies local quality by allowing different instruments and keypoints to have varying levels of attention and influence. The attention mechanism assigns different weights to different instruments based on their relevance to the current surgical context, enabling the system to adapt to local interaction patterns while maintaining precise keypoint detection through specialized spatial networks.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention introduces an attention mechanism as an intermediary between the spatial and temporal networks. This attention layer processes the spatial features and historical trajectories, dynamically weighting the influence of different instruments and keypoints, thereby bridging the gap between general tracking capabilities and surgery-specific interaction modeling.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If complex spatiotemporal modeling is implemented to capture instrument interactions, then tracking reliability improves, but computational complexity and processing time increase

Engineering Contradiction:
Improvetracking reliabilityVSAvoidprocessing time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The model performs preliminary action by pre-processing spatial features and historical trajectories separately before combining them in the temporal network. The spatial network extracts keypoint locations in advance, and the temporal network uses this pre-processed information along with historical data to predict trajectories, reducing computational complexity during real-time processing while maintaining tracking reliability.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentUS20240296604A1Systems and methods for keypoint detection and tracking-by-prediction for multiple surgical instruments
Publication Date: 2024.09.05 INTUITIVE SURGICAL OPERATIONS INC
  • US20240296604A1 patent drawing
  • US20240296604A1 patent drawing
  • US20240296604A1 patent drawing

AI summary

A method for detecting a location of a plurality of keypoints of a surgical instrument comprises receiving, at a first neural network model, a video input of a surgical procedure. The method further comprises generating, using the first neural network model, a first output image including a first output location of the plurality of keypoints annotated on a first output image of the surgical instrument. The method further comprises receiving, at a second neural network model, the first output image and historic keypoint trajectory data including a historic trajectory for the plurality of keypoints. The method further comprises determining, using the second neural network model, a trajectory for the plurality of keypoints. The method further comprises generating, using the second neural network model, a second output image including a second output location of the plurality of keypoints annotated on a second output image of the surgical instrument.