PGA Patch with Star-Shaped Frame for Bladder Wall Repair

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Solution Overview

Problem

Existing bladder patches face challenges such as collapsibility under growing tissue weight, uneven tissue growth, adherence to the fibrous capsule, and impermeability issues, requiring subsequent surgical removal and being unsuitable for curved bladder sections.

Innovation Solution

A self-supporting, absorbable patch made of PGA textile with a star-shaped frame in PGA/PLA copolymer, providing mechanical strength, flexibility, and impermeability, allowing for even tissue growth without adherence to the fibrous capsule and eliminating the need for subsequent surgical removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of moving object

If a homogeneous PGA patch is used, then the absorption time matches the tissue growth time (30 days), but the mechanical properties decline during absorption leading to patch collapse under growing tissue weight

Engineering Contradiction:

Improveabsorption timeVSAvoidmechanical properties

Core Design Contradiction:

Duration of action of moving objectVSStrength

Solution Approach 1:

The patch is divided into two distinct layers: a porous inner layer for tissue ingrowth and absorption, and a non-porous outer reinforcement layer that maintains mechanical strength and impermeability throughout the absorption period. This segmentation allows each layer to perform its specific function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patch combines two different PGA materials with contrasting properties: a porous absorbable material for tissue integration and a non-porous reinforcement material for structural support. This composite structure resolves the contradiction by allowing simultaneous absorption and mechanical stability.

Inventive Principle:

Principle #40Composite materials

2Object-generated harmful factors

If a highly porous patch is used to allow tissue populating, then tissue growth is facilitated, but urine leakage occurs through the porous structure

Engineering Contradiction:

Improvetissue populating capabilityVSAvoidurine leakage

Core Design Contradiction:

Object-generated harmful factorsVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the patch have different porosity characteristics: the inner layer is highly porous to facilitate tissue ingrowth, while the outer layer is non-porous to prevent urine leakage. This local differentiation of properties resolves the contradiction between tissue populating and urine impermeability.

Inventive Principle:

Principle #3Local quality

3Shape

If a rigid patch is used to maintain bladder shape, then structural support is provided, but the patch cannot deform during physiological bladder functioning

Engineering Contradiction:

Improvebladder shape retentionVSAvoiddeformation capability

Core Design Contradiction:

ShapeVSAdaptability or versatility

Solution Approach 1:

The reinforcement layer is designed as a thin, flexible membrane that provides structural support while allowing deformation. This thin-film reinforcement maintains bladder shape during filling and emptying cycles without preventing physiological movement or collapse.

Inventive Principle:

Principle #30Flexible shells and thin films

4Ease of manufacture

If a flat patch is used for simplicity, then manufacturing is easier, but the patch cannot adapt to curved bladder sections

Engineering Contradiction:

Improvepatch fabricationVSAvoidconformability to curved surfaces

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patch is designed with inherent flexibility and thinness that allows it to conform to curved bladder surfaces. The reinforcement layer's geometry and material properties enable adaptation to various bladder shapes and curvatures while maintaining structural integrity.

Inventive Principle:

Principle #14Spheroidality (Curvature)

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 patch maintains bladder shape and functionality, ensures even tissue growth, prevents urine leakage, and adapts to curved bladder sections, reducing the need for subsequent surgeries and improving tissue regeneration.

Implementation Method 1

a frame, with flat or planar structure, formed by a plurality of radial reinforcement strips (5), which detach from the centre of the frame moving outwards

Methodology Applied

Scientific EffectComposite materials: Composite Materials

Implementation Method 2

absorbable materials (bioabsorbable)... Textile is made by using a multifilament or ultra-lightweight monofilament yarn, deriving from fibres of PGA

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Implementation Method 3

absorbable patch in PGA fibres... absorption time of the order of 30 days

Methodology Applied

Scientific EffectBiodegradation: Decomposition (biological)

Data Source

PatentEP2825128B1Improved absorbable patch, in reinforced PGA, for the replacement of a portion of bladder wall following partial cystectomy

Publication Date: 2018.04.25 SAMBUSSETI ANTONIO

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Figure 3~4

AI summary

A description is given of a patch (1) for the replacement of a portion of bladder wall, following partial cystectomy, comprising a textile (2) deriving from a PGA yarn and provided with a star-shaped support frame, flexible and harmonic, formed by a plurality of radial strips (3) manufactured by injection of a PGA/PLA copolymer, said patch (1) being suitable for making autologous fibrous capsule cells, generated by the process of tissue reconstruction, grow thereon after its insertion inside the patient.