Shape Memory Snare Loop for Endoscopic Polyp Removal

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Solution Overview

Problem

Conventional snare devices for removing polyps are bulky and unsuitable for endoscopic procedures due to mechanical linkages, making them difficult to maneuver and position accurately, especially for small or hard-to-reach polyps, and often require destructive methods that prevent tissue biopsy.

Innovation Solution

A tissue snare with a loop formed of shape memory material that transitions from an expanded to a constricted state when heated, allowing for controlled constriction around the polyp without the need for manual actuation or bulky mechanical linkages, enabling precise removal and biopsy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If mechanical linkages are used to tighten the snare loop, then the loop can be manually controlled, but the device becomes bulky and unsuitable for endoscopic procedures

Engineering Contradiction:

Improvemanual control of loop tighteningVSAvoiddevice size

Core Design Contradiction:

Ease of operationVSVolume of moving object

Solution Approach 1:

The patent replaces the mechanical linkage system with a thermal actuation system. The shape memory alloy loop responds to temperature changes (heating) to automatically constrict, eliminating the need for mechanical levers, pulleys, cables, or other manual tightening mechanisms. This substitution of mechanical control with thermal control resolves the contradiction by enabling loop tightening without bulky mechanical components.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the control parameter from mechanical force to temperature. By heating the shape memory alloy loop above its transformation temperature, the material undergoes a phase change that causes automatic constriction. This parameter change eliminates the need for mechanical linkages while maintaining controllable loop tightening, thereby reducing device size for endoscopic use.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If destructive techniques are used to remove polyps, then complete removal is achieved, but tissue biopsy is prevented

Engineering Contradiction:

Improvepolyp removal efficiencyVSAvoidtissue integrity for biopsy

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent applies partial action by using the shape memory alloy loop to constrict and ligate the polyp base without completely destroying the tissue. The gradual constriction allows the polyp to be separated while preserving the base tissue structure, enabling subsequent biopsy. This partial action approach achieves polyp removal while maintaining tissue integrity for pathological evaluation.

Inventive Principle:

Principle #16Partial or excessive action

3Volume of moving object

If the snare device is made compact for endoscopic use, then it can be inserted endoscopically, but manual tightening mechanisms become difficult to maneuver and position accurately

Engineering Contradiction:

Improvedevice sizeVSAvoidpositioning accuracy

Core Design Contradiction:

Volume of moving objectVSEase of operation

Solution Approach 1:

The patent replaces manual mechanical tightening mechanisms with automatic thermal actuation. The shape memory alloy loop automatically constricts when heated, eliminating the need for complex manual manipulation of mechanical components. This substitution maintains device compactness while improving positioning accuracy through controlled thermal response.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 shape memory snare device allows for precise and minimally invasive polyp removal, maintaining tissue integrity for biopsy and reducing the risk of mechanical failure, while being suitable for endoscopic procedures by controlling the constriction mechanism thermally.

Implementation Method 1

the loop being formed of a shape memory material having a critical temperature so that, when a temperature of the loop is above the critical temperature, the loop transitions from the expanded configuration to a constricted configuration

Methodology Applied

Scientific EffectShape memory effect: Shape Memory Alloy

Implementation Method 2

when a temperature of the loop exceeds a critical temperature thereof, the loop constricts from an expanded state to a constricted state

Methodology Applied

Scientific EffectThermal heating: Heating

Data Source

PatentUS9186169B2Snare with loop made of heat shrinkable shape memory material and method of use thereof

Publication Date: 2015.11.17 BOSTON SCIENTIFIC SCIMED INC

AI summary

A tissue snare comprises an elongated member having a distal end and a loop formed of a shape memory material, the loop including a tissue receiving interior opening and being connected to the distal end of the elongated member, properties of the shape memory material being selected so that, when a temperature of the loop exceeds a critical temperature thereof, the loop constricts from an expanded state to a constricted state. A method of treating tissue comprises placing a loop of a snare around a portion of tissue to be treated while the loop is in an expanded configuration, the loop being formed of a shape memory material having a critical temperature so that, when a temperature of the loop is above the critical temperature, the loop transitions from the expanded configuration to a constricted configuration in combination with transitioning, after the loop has been placed around the portion of tissue to be treated, the loop from the expanded configuration to the constricted configuration to tighten the loop around the portion of tissue to be treated.