Urological Chitosan Stent with Expandable Tip for Catheter Insertion

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Solution Overview

Problem

Existing prostatic stents used in urological procedures often have either closed or too open tips, which can lead to insufficient bladder irrigation and flushing due to the inability to insert a catheter to a suitable depth or the requirement for a thin catheter that may not provide adequate irrigation.

Innovation Solution

A stent apparatus comprising a first bioresorbable scaffold structure with an inner lumen, an expandable second bioresorbable layer positioned on the first layer such that its ends extend beyond those of the first layer, and an expandable balloon within the distal end of the inner lumen. This configuration allows for effective expansion and positioning of the stent within the prostatic urethra, ensuring sufficient irrigation and drainage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the stent has a closed tip configuration, then the stent structure is simpler and easier to manufacture, but the catheter cannot be inserted to a suitable depth into the bladder for sufficient irrigation

Engineering Contradiction:

Improvestent structure simplicityVSAvoidcatheter insertion depth

Core Design Contradiction:

Ease of manufactureVSEase of operation

Solution Approach 1:

The stent is divided into two functional layers: a first layer (scaffold structure) that provides structural support and a second layer (expandable layer) that creates the open tip configuration. This segmentation allows each layer to fulfill its specific function - the scaffold maintains stent integrity while the expandable layer forms the funnel shape for catheter insertion

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The expandable layer is pre-positioned on the scaffold structure in a compressed state during manufacturing. After stent implantation, the expandable layer is then expanded to form the open tip configuration, allowing the catheter to be inserted to the required depth without compromising the stent's structural integrity during insertion

Inventive Principle:

Principle #10Preliminary action

2Ease of operation

If the stent has a more open tip configuration, then the catheter can be inserted to suitable depth, but the catheter must be thin (e.g., 14 Fr.) which may provide insufficient irrigation

Engineering Contradiction:

Improvecatheter insertion depthVSAvoidirrigation effectiveness

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The expandable layer is applied locally at the distal end of the scaffold structure to create a funnel-shaped open tip configuration. This localized modification allows the tip to be sufficiently open for catheter insertion while the rest of the stent maintains its structural integrity and support function

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The expandable layer transitions from a compressed state during implantation to an expanded state after deployment. This dynamic transformation allows the stent tip to change from a closed configuration during insertion to an open configuration for catheter insertion and effective irrigation

Inventive Principle:

Principle #15Dynamics

3Ease of operation

If a thin catheter is used to insert past the braid and chitosan sponge, then the catheter can reach suitable depth, but the irrigation and flushing may be insufficient due to the thin size

Engineering Contradiction:

Improvecatheter insertion past braid and spongeVSAvoidirrigation and flushing adequacy

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

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 described stent apparatus ensures effective bladder irrigation and drainage by maintaining a sufficiently open inner lumen for catheter insertion and expansion against the urethral wall, addressing the limitations of existing stent designs.

Implementation Method 1

an expandable balloon located within a distal end of the inner lumen of the first layer

Methodology Applied

Scientific EffectMechanical expansion: Elasticity

Implementation Method 2

the second layer comprises a bioresorbable material configured to expand

Methodology Applied

Scientific EffectMaterial expansion: Hydrogel

Data Source

PatentUS20250143902A1Urological chitosan stent and delivery system

Publication Date: 2025.05.08 OLYMPUS CORPORATION(JP)

AI summary

An apparatus includes a first layer, wherein the first layer comprises a scaffold structure forming an inner lumen along a length of the scaffold structure, and wherein the first layer comprises a bioresorbable material; a second layer on the first layer, wherein the second layer comprises a bioresorbable material configured to expand, wherein the second layer is positioned on the first layer such that ends of the first layer extend beyond ends of the second layer; and an expandable balloon located within a distal end of the inner lumen of the first layer.