Undulating Urethral Expander to Reduce Stent Migration and Encrustation

Solution Overview

Problem

Existing prostatic stents for treating benign prostatic hyperplasia (BPH) suffer from high rates of migration, encrustation, blockage, pain, and disruption of natural urethral movements due to their circumferential design and rigidity, which do not accommodate the unique anatomy of the prostatic urethra.

Innovation Solution

A resiliently deformable undulating ring expander with longitudinal struts and prongs that conform to the urethral anatomy, minimizing contact area and allowing for differential flexing, reducing encrustation and facilitating easy removal while maintaining urethral functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional cylindrical stents are used in the prostatic urethra, then immediate relief from BPH symptoms is achieved, but high rates of migration, encrustation, blockage, and pain occur due to rigidity and failure to accommodate natural urethral movements

Engineering Contradiction:

Improvestent retention and functionalityVSAvoidmigration, encrustation, blockage, and pain

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The stent transitions from a static rigid structure to a dynamic self-expanding structure that can adapt to natural urethral movements during urination and ejaculation. The self-expanding mechanism allows the stent to flex and move with the urethra, preventing pain and dislodgement while maintaining patency.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The stent employs a flexible membrane structure that allows the urethral lumen to expand and contract naturally during physiological functions. This flexibility accommodates urethral movements without causing pain or dislodgement, while the membrane maintains the structural integrity needed to prevent encrustation and blockage.

Inventive Principle:

Principle #30Flexible shells and thin films

2Strength

If circumferential ring stents are used to maintain urethral patency, then structural support is provided, but the rigidity impedes natural movements of the prostatic urethra during urination and ejaculation causing pain

Engineering Contradiction:

Improvestructural support for urethral patencyVSAvoidpain during urination and ejaculation

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The stent transitions from a static rigid structure to a dynamic self-expanding structure that can adapt to natural urethral movements during urination and ejaculation. The self-expanding mechanism allows the stent to flex and move with the urethra, preventing pain and dislodgement while maintaining patency.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The stent employs a flexible membrane structure that allows the urethral lumen to expand and contract naturally during physiological functions. This flexibility accommodates urethral movements without causing pain or dislodgement, while the membrane maintains the structural integrity needed to prevent encrustation and blockage.

Inventive Principle:

Principle #30Flexible shells and thin films

3Productivity

If traditional stents are placed in the prostatic urethra, then urinary flow resistance is reduced, but migration to the bladder or membranous urethra occurs in up to 12.5% of patients

Engineering Contradiction:

Improveurinary flowVSAvoidstent position stability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The stent is designed with non-uniform structural characteristics, being larger at the proximal end (bladder end) and smaller at the distal end (penile end). This asymmetric design creates a geometric lock that prevents migration to the bladder while accommodating the natural taper of the prostatic urethra, ensuring stable positioning without blocking urinary flow.

Inventive Principle:

Principle #3Local quality

4Strength

If spaced-apart interconnected rings are used as urethral expanders, then expansion is achieved, but the circumferential disposition increases encrustation as they meet urine at 90° and the rigidity impedes natural movements

Engineering Contradiction:

Improveexpansion capabilityVSAvoidencrustation and rigidity-induced pain

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The stent employs a flexible membrane structure that allows the urethral lumen to expand and contract naturally during physiological functions. This flexibility accommodates urethral movements without causing pain or dislodgement, while the membrane maintains the structural integrity needed to prevent encrustation and blockage.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The stent transitions from a static rigid structure to a dynamic self-expanding structure that can adapt to natural urethral movements during urination and ejaculation. The self-expanding mechanism allows the stent to flex and move with the urethra, preventing pain and dislodgement while maintaining patency.

Inventive Principle:

Principle #15Dynamics

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 undulating ring expander effectively dilates the prostatic urethra, reducing encrustation and migration risks, and allows for anatomical conformity during urination and ejaculation, providing a more comfortable and effective treatment for BPH.

Implementation Method 1

The expander is resiliently deformable in a radial direction between a contracted orientation suitable for transluminal delivery to the target site through the body lumen and an expanded (deployed) orientation configured to effect in-situ dilation of the body lumen at the target site

Methodology Applied

Scientific EffectElastic deformation: Elasticity

Data Source

PatentUS20260096912A1Catheter for deploying an expander in a urethra

Publication Date: 2026.04.09 PROVERUM LTD

AI summary

A catheter for deploying an implantable expander in a urethra. An implantable biocompatible expander suitable for implantation into a urinary duct is resiliently deformable from a relaxed radially expanded orientation to a radially contracted orientation suitable for transluminal delivery through the urinary duct. The expander may be configured to exert an outward radial force against a wall of the urinary duct when in-situ within the urinary duct. In particular, the expander is suitable for treatment of benign prostatic hyperplasia and configured for implantation into the prostatic urethra between, and substantially spanning the prostatic urethra between, the bladder neck and external sphincter.