Surgical Instrument Force Sensing for Tissue-Safe Control

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Solution Overview

Problem

Existing surgical instruments lack comprehensive force sensing and control systems to accurately monitor and manage the application of forces during tissue manipulation, clipping, and suturing, which can lead to inefficiencies and potential tissue damage.

Innovation Solution

A surgical system with a strain gage circuit and torque-force sensors integrated into the tool shaft, coupled with a signal processor to determine the magnitude and position of lateral forces, providing precise control and feedback for grasping, dissecting, and suturing operations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If surgical instruments are equipped with comprehensive force sensing and control systems, then measurement precision and reliability are improved, but device complexity increases

Engineering Contradiction:
Improveforce sensing precisionVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The surgical instrument shaft is divided into multiple sections with strain gages positioned at different locations (proximal, intermediate, and distal positions). Each strain gage measures forces at specific segments, allowing the system to determine both magnitude and position of applied forces through distributed sensing rather than a single complex sensor.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A signal processor acts as an intermediary between the strain gage circuits and the control system. It receives raw strain gage signals, processes them to calculate force magnitude and position, and provides interpreted data to the control system, simplifying the overall system architecture and reducing control complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If strain gage circuits and torque-force sensors are integrated into the tool shaft, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveforce and torque measurement precisionVSAvoidsensor integration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Multiple sensing functions (strain measurement, torque measurement, and force measurement) are merged into a single integrated shaft structure. Strain gages and torque-force sensors are combined within the same shaft, allowing simultaneous measurement of multiple parameters without requiring separate instrument components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The shaft is designed as a multi-functional component that simultaneously serves as the structural element, the sensing element, and the transmission element. It provides mechanical support, measures forces and torques through integrated sensors, and transmits control forces, reducing the need for separate components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Object-affected harmful factors

If precise control and feedback systems are implemented, then tissue damage is reduced and surgical safety is improved, but device complexity increases

Engineering Contradiction:
Improvetissue damageVSAvoidcontrol and feedback system complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

A feedback control system continuously monitors forces applied to tissue through strain gage measurements and adjusts the instrument actuation accordingly. The signal processor provides real-time feedback on force magnitude and position, allowing the control system to prevent excessive forces that could damage tissue while maintaining surgical effectiveness.

Inventive Principle:
Principle #23Feedback

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

Enhances the precision and safety of surgical procedures by accurately monitoring and controlling applied forces, reducing tissue damage and improving operational efficiency.

Implementation Method 1

a strain gage circuit including a Wheatstone bridge and a strain gage affixed to a surgical instrument shaft... the strain gage is configured to detect and measure strain and force applied to the surgical instrument shaft

Methodology Applied
Scientific EffectStrain gage measurement: Piezoresistive Effect

Implementation Method 2

at least one torque-force sensor arranged at a second position along the surgical instrument shaft

Methodology Applied
Scientific EffectTorque measurement: Torque

Data Source

PatentEP4104773B1Surgical instrument comprising a control system that uses input from a strain gage circuit
Publication Date: 2026.02.11 ETHICON INC
  • EP4104773B1 patent drawingFigure 1
  • EP4104773B1 patent drawingFigure 2
  • EP4104773B1 patent drawingFigure 3

AI summary

A surgical instrument is disclosed comprising a control system and a strain gage circuit. The operation of the control system is modifiable by an input from the strain gage circuit.