Aspiration Device Nested Cavity Tissue Deformability

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for measuring the elastic and viscoelastic properties of soft and very soft tissues are limited by external force perturbations, complexity, cost, and accuracy, particularly when measuring non-exposed surfaces or requiring sterilization, which hinders reliable characterization of time-dependent tissue behavior.

Innovation Solution

A lightweight, minimally invasive aspiration device with a small probe head and flexible tubes allows for precise measurement of pressure differences to determine tissue deformability, minimizing external forces and enabling accurate characterization of viscoelastic properties without the need for complex setups or skilled operators.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a fixed tissue displacement distance method is used with a large cavity to provide significant volume ratio, then measurement precision is improved, but the probe head becomes bulky

Engineering Contradiction:
Improvemeasurement precisionVSAvoidprobe head volume
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent implements nesting by placing a smaller internal aspiration cavity within a larger external cavity structure. The internal cavity has a volume of 0.5-2 mL while the external cavity provides additional volume, creating a nested configuration that achieves the required volume ratio without increasing the overall probe head size. This allows precise measurement of tissue displacement while maintaining a compact probe design suitable for intra-corporal use.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Measurement precision

If a camera is incorporated into the probe head to measure displacement, then measurement capability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvedisplacement measurement capabilityVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the optical measurement system (camera) with a pressure-based mechanical sensing system. By measuring the negative pressure required to aspirate a fixed volume of tissue into the cavity, the system determines tissue deformability without requiring visual measurement equipment. This substitution simplifies the device structure, reduces cost, and eliminates the need for complex image processing while maintaining measurement accuracy.

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

3Device complexity

If a syringe-type suction means is used to measure skin deformation, then device simplicity is improved, but measurement accuracy deteriorates due to poor volume accuracy

Engineering Contradiction:
Improvedevice simplicityVSAvoidvolume measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent extracts the measurement function from the suction mechanism itself. Instead of using the syringe plunger position to measure volume (which has poor accuracy), the system uses a separate pressure sensor to measure the negative pressure required to aspirate a pre-defined fixed volume of tissue. This separation of the suction function from the measurement function allows the use of simple suction means while achieving high measurement accuracy through pressure detection.

Inventive Principle:
Principle #2Taking out (Extraction)

4Reliability

If a lightweight probe head is used to minimize external forces, then reliability of tissue state is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvenon-perturbed initial conditionVSAvoidcavity volume precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by pre-defining the internal cavity volume during manufacturing within a specific range (0.5-2 mL). This predetermined volume is established before use, allowing the device to function with minimal external forces while maintaining measurement reliability. The fixed volume design eliminates the need for complex real-time volume adjustment mechanisms, reducing manufacturing complexity while ensuring consistent performance across devices.

Inventive Principle:
Principle #10Preliminary action

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 device provides high-precision, reproducible measurements of viscoelastic properties for soft tissues and synthetic materials, suitable for in situ analysis with minimal user-generated forces and compatibility with sterilization methods, overcoming previous limitations in accuracy and usability.

Implementation Method 1

a probe head (1) having a cavity (11), for instance with a volume between 0.5 and 2 milliliter, and with at least one opening (13, 14) connected to a pump (2), wherein the pump (2) is adapted to provide a negative pressure of at least 100 mbar

Methodology Applied
Scientific EffectNegative pressure: Pressure Gradient

Implementation Method 2

with a pressure sensor (23) adapted to detect a pressure difference between the two airways (2, 23)

Methodology Applied
Scientific EffectPressure detection:

Data Source

PatentEP3534773B1Aspiration device and method for determining viscoelastic properties of biological tissues and synthetic materials
Publication Date: 2021.11.24 ETH ZURICH
  • EP3534773B1 patent drawingFigure 1~2
  • EP3534773B1 patent drawingFigure 3~4
  • EP3534773B1 patent drawingFigure 5~6

AI summary

A device for measuring the elastic deformability of soft tissue comprises a probe head (1) having the form of a cup with a cavity (11), side walls (37) and a bottom wall (38, 39), a first probe channel (22), a pressure unit and a control unit, the first probe channel (22) being configured to connect the pressure unit, that provides a vacuum inside first probe channel (22) and that is controlled by the control unit, with the probe head (1), wherein the first probe channel (22) has a distal end (14) leading through the bottom wall (39) into the cavity (11). The device further comprises a second probe channel (23) having a distal end leading through the bottom wall (39) into the cavity (11) and being connected with a pressure sensor provided to determine the pressure in the cavity (11) and to communicate it to the control unit to determine the point in time, when deformed tissue closes the distal end (14) of the first probe channel (22) based on a pressure difference in the two probe channels (22 and 23), wherein the two probe channels (2; 22, 23) are flexible tubes (2) passing loosely through a hollow sleeve (30, 31, 32, 33) allowing an essentially free relative movement between probe head (1) and hollow sleeve (30, 31, 32, 33).