Ureteral Stent Deformable Bladders for Positioning and Reflux Prevention

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Solution Overview

Problem

Ureteral stents often cause discomfort and pain due to irritation of the trigone area and can lead to urine reflux, as they may move within the ureter, causing partial collapse and interfering with normal urine flow.

Innovation Solution

A ureteral stent with an elongated stent body and deformable bladders secured to its ends, which are imperforately sealed with inert fluid, to reduce movement, improve comfort, and facilitate insertion and retrieval, by expanding to maintain position within the ureter and prevent urine reflux.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a stent is inserted into the ureter to maintain urine flow, then urine flow obstruction is resolved, but the stent may move within the ureter causing discomfort and pain

Engineering Contradiction:

Improveurine flow maintenanceVSAvoidstent movement causing discomfort

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The stent incorporates deformable bladders that can dynamically change shape and position to adapt to ureteral movements and patient activity levels. The bladders transition between compressed and expanded states, allowing the stent to maintain secure positioning while accommodating physiological changes, thereby preventing discomfort and pain associated with rigid stent movement.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The stent utilizes temperature-responsive materials that change physical properties in response to body temperature variations. The deformable bladders expand or contract based on temperature changes, enabling the stent to maintain optimal positioning and prevent movement-related discomfort while ensuring continuous urine flow.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If a stent is positioned in the ureter to prevent obstruction, then urine flow is restored, but the stent may irritate the trigone area causing patient discomfort

Engineering Contradiction:

Improveureteral patencyVSAvoidtrigone irritation

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The stent features differentiated regions with specialized properties: the deformable bladders are positioned to contact the trigone area, providing localized pressure distribution and irritation prevention. The main stent body maintains rigidity for patency, while the bladder regions offer compliant, adaptive contact with sensitive trigone tissues, reducing discomfort.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The deformable bladders act as intermediary structures between the rigid stent body and the sensitive trigone area. These bladders distribute contact forces over a larger area and provide a compliant interface, mediating the interaction between the stent and trigone tissues to minimize irritation while maintaining stent positioning.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If a stent is placed in the ureter to maintain flow, then obstruction is prevented, but the stent may cause urine reflux by interfering with normal flow

Engineering Contradiction:

Improveurine flow maintenanceVSAvoidurine reflux

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The deformable bladders dynamically respond to pressure changes during bladder contraction and urine flow. As the bladder compresses during voiding, the stent configuration adapts to maintain proper flow direction and prevent retrograde pressure transmission, thereby preventing urine reflux while maintaining patency.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The stent utilizes pressure-responsive materials that change configuration based on intravesical pressure variations. During normal voiding, the materials remain flexible to allow flow; during retrograde pressure attempts, the materials stiffen or reconfigure to block reflux pathways while maintaining forward flow capability.

Inventive Principle:

Principle #35Parameter changes

4Reliability

If a rigid stent is used to maintain ureteral patency, then urine flow is ensured, but the stent cannot accommodate patient activity causing movement and discomfort

Engineering Contradiction:

Improveureteral patencyVSAvoidaccommodation of patient activity

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The stent combines rigid materials for the main body (ensuring patency) with flexible, deformable materials for the bladder portions (enabling activity accommodation). This composite construction allows different segments of the stent to have different mechanical properties, simultaneously achieving ureteral patency maintenance and adaptability to patient movement.

Inventive Principle:

Principle #40Composite materials

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 deformable bladders secure the stent in place, reducing movement and discomfort, while preventing urine reflux by maintaining a stable position between the kidney and bladder, enhancing patient comfort and the effectiveness of the stent's placement.

Implementation Method 1

deformable bladders secured to an end region of an elongated stent body... expanding to maintain position within the ureter

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS11224502B2Ureteral stents and methods of using the same

Publication Date: 2022.01.18 CR BARD INC

AI summary

Embodiments disclosed herein relate to ureteral stents having an elongated stent body and one or more deformable bladders secured thereto, and methods of using the same.