Toroidal Balloon Inversion for Low-Friction Stone Extraction

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Solution Overview

Problem

Current techniques for removing stones from the urinary and biliary systems are cumbersome, inefficient, and risky, often requiring high-pressure balloon dilation and carrying the risk of ureteral injury, with existing devices either lacking direct visualization or relying on suction, which can cause frictional damage.

Innovation Solution

A toroidal balloon attached only at the distal end of a guide, allowing for low-friction extraction by inverting its internal and external surfaces, minimizing contact with biological walls and reducing the risk of injury during stone removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a high pressure balloon is used for dilation to allow stone extraction, then the capacity of the ureter is increased and resistance is decreased, but the ureter is placed at risk for stricture formation and traumatic injury

Engineering Contradiction:

Improvestone extraction capabilityVSAvoidureteral injury risk

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The balloon is inverted inside the ureter during extraction, with the internal surface facing outward and the external surface facing inward. This inversion allows the balloon to be withdrawn through the ureter without the external surface contacting and damaging the ureteral wall, thereby enabling stone extraction while minimizing traumatic injury to the ureter.

Inventive Principle:

Principle #13The other way round (Inversion)

2Measurement precision

If a basket device is used to engage and withdraw the stone, then direct vision engagement is achieved, but frictional damage to the ureteral mucosa and wall occurs during extraction

Engineering Contradiction:

Improvedirect vision engagementVSAvoidfrictional damage to ureteral mucosa

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The balloon is inverted during extraction so that its internal surface, which has low friction characteristics, faces outward and contacts the ureteral wall during withdrawal. This inversion converts the high-friction external surface into an internal surface that slides against the ureteral wall with minimal friction, thereby reducing frictional damage to the ureteral mucosa while maintaining the ability to engage and withdraw the stone under direct vision.

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If the balloon is attached at both proximal and distal ends of the catheter, then the stone is protected within the balloon during intussusception, but the external surface of the balloon is withdrawn in direct opposition to the ureteral wall causing injury risk

Engineering Contradiction:

Improvestone protection during extractionVSAvoidureteral wall injury risk

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The balloon is inverted inside the ureter during extraction, positioning the internal surface facing outward and the external surface facing inward toward the catheter. This inversion ensures that when the balloon is withdrawn, the internal surface (which has low friction) contacts the ureteral wall rather than the external surface, thereby protecting the stone within the balloon while minimizing injury risk to the ureteral wall during withdrawal.

Inventive Principle:

Principle #13The other way round (Inversion)

4Ease of operation

If suction is used to engage the stone, then the stone can be drawn into the balloon, but suction is ineffective for stones with irregular surfaces not amenable to suction seal

Engineering Contradiction:

Improvestone engagementVSAvoidapplicability to irregular surface stones

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The balloon is inverted during extraction, allowing the internal surface to contact and engage the stone directly. This inversion enables the balloon to engage stones with irregular surfaces through direct contact with the internal surface, which can conform to irregular geometries, rather than relying on suction seals that require smooth surfaces. The inverted configuration allows the balloon to envelop and secure irregularly shaped stones effectively.

Inventive Principle:

Principle #13The other way round (Inversion)

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 toroidal balloon enables safe and efficient removal of stones with minimal friction, reducing the risk of ureteral injury and avoiding the need for high-pressure dilation, while maintaining direct visualization and control over the stone.

Implementation Method 1

allowing low friction extraction by sliding of said internal balloon surface of said toroidal balloon

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS8529581B2Method and device for extracting objects from the body

Publication Date: 2013.09.10 TOROIDAL FOLEY LLC

AI summary

A device for extracting (or inserting) objects from the body, such as urinary stones, using a low pressure inflatable toroidal balloon that serves to engulf the object during extraction (or insertion) while dilating and protecting the passageway. The balloon loads onto an ureteroscope prior to insertion, rather than through the ureteroscope as do existing balloons. The toroidal balloon is a simple and unique device that may be applied external to the extracting telescope and does not interfere with existing methods for stone manipulation such as laser lithotripsy, irrigation and basket extraction in the case of urinary stone manipulation.