Surgical Robot Tissue Stiffness Estimation via Visual Overlay

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current teleoperated robot-assisted surgical systems lack realistic haptic feedback, making it difficult for surgeons to estimate tissue properties and differentiate between normal and abnormal tissues during procedures like coronary artery bypass grafting, where calcified arteries are hard to detect visually.

Innovation Solution

A surgical robot system that includes a processor, imaging system, and visual display, which uses tool-environment interaction data to estimate mechanical properties of tissues and overlays a composite image with a mechanical property map on the environment image, providing real-time feedback on tissue stiffness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If teleoperated robot-assisted surgical systems are used, then dexterity and precision are improved, but haptic feedback is lost making tissue property estimation difficult

Engineering Contradiction:
Improvetissue property estimation accuracyVSAvoidhaptic feedback
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent replaces the mechanical haptic feedback system with an optical/electronic visualization system. Instead of providing force feedback through the robotic manipulator, the system uses cameras to capture tissue deformation and other visual cues, then processes these signals to generate color-coded overlays that represent tissue stiffness and mechanical properties on the display screen, allowing surgeons to estimate tissue properties without direct haptic feedback.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary processing system between the robotic manipulator and the surgeon. This intermediary system includes signal processing circuits that analyze tool-tissue interaction forces and tissue deformation, convert this data into visual representations, and display it as color-coded overlays. This intermediary translates mechanical interactions into visual information that the surgeon can interpret.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If visual cues alone are used for tissue differentiation, then system complexity is reduced, but ability to detect calcified arteries and tissue abnormalities deteriorates

Engineering Contradiction:
Improvetissue abnormality detection accuracyVSAvoidmechanical property information
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent employs color-coded visual overlays to represent different tissue mechanical properties. Tissue stiffness, elasticity, and other mechanical characteristics are mapped to different colors displayed on the screen. This allows surgeons to differentiate between normal and abnormal tissues, and identify calcified arteries, based on color variations that correspond to underlying mechanical property differences.

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The patent adds a new dimension of information by overlaying processed mechanical property data onto the standard visual field. Instead of relying solely on the natural visual appearance of tissues, the system superimposes color-coded maps that represent mechanical properties in a second layer of information, enabling surgeons to perceive tissue characteristics that are not visible through conventional visual inspection alone.

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

3Measurement precision

If force feedback mechanisms are implemented, then tissue property estimation is improved, but device complexity and cost increase

Engineering Contradiction:
Improvemechanical property measurement accuracyVSAvoidforce feedback system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent enables the surgical system to self-measure tissue mechanical properties by analyzing signals already generated during normal surgical manipulation. The system uses the existing tool-tissue interaction forces and tissue deformation that occur during surgery, processes these signals through analysis circuits, and derives mechanical property information without requiring separate force feedback actuators or additional sensing mechanisms.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent introduces an intermediary signal processing system that acts as a mediator between the mechanical interactions and the surgeon. This intermediary includes processing circuits that analyze tool-tissue interaction forces and tissue deformation signals, convert this mechanical data into visual representations, and display it as color-coded overlays on the screen, providing measurement capability without complex force feedback hardware.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP2355711B1Environment property estimation and graphical display
Publication Date: 2019.09.11 JOHNS HOPKINS UNIVERSITY
  • EP2355711B1 patent drawingFigure 1
  • EP2355711B1 patent drawingFigure 2A~2C
  • EP2355711B1 patent drawingFigure 3

AI summary

A surgical robot including an imaging system comprising at least one camera, a processor in communication with the imaging system, a manipulation system in communication with the processor, and a visual display in communication with the processor. The processor is operable to calculate a stiffness estimate for an area of an environment based on an environment model of tool-environment interaction data, create a composite image comprising a stiffness map of the stiffness estimate overlaid on an environment image from the at least one camera, and output the composite image on the visual display.