Invaginated Prostatic Stent Anchoring to Prevent Encrustation

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Solution Overview

Problem

Current treatments for urinary retention due to benign prostatic hyperplasia (BPH) often involve invasive procedures or less-invasive methods that can lead to complications such as epithelialization, encrustation, and migration of stents, resulting in discomfort and re-obstruction.

Innovation Solution

Deployment of expandable structures or scaffolds within the prostatic urethra to maintain patency, which can be anchored to prevent migration and incorporate biologic agents or energy-emitting capabilities to inhibit tissue growth and protect against calcification, allowing for adjustable sizing and deployment configurations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If prostatic stents are deployed to maintain urethral patency, then urinary flow is improved, but the stents become excessively epithelialized, encrusted, migrated, or calcified leading to discomfort and re-obstruction

Engineering Contradiction:
Improveurethral patency maintenanceVSAvoidepithelialization, encrustation, migration, calcification
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent removes the stent from contact with the urine stream by invaginating it into the prostatic tissue. The stent is embedded within the prostate gland rather than being exposed to urine, which eliminates the harmful effects of epithelialization, encrustation, migration, and calcification while maintaining urethral patency through the invaginated structure.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If invasive surgical procedures are performed to treat BPH, then urinary obstruction is relieved, but post-operative pain and prolonged catheterization occur with high risk of sexual side effects

Engineering Contradiction:
Improveobstruction reliefVSAvoidpost-operative pain, prolonged catheterization, sexual side effects
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the fundamental parameter of treatment invasiveness by using a minimally invasive approach. Instead of open or robotic surgery requiring general anesthesia, the invention employs percutaneous needle delivery of expandable implants that are inserted through the prostate tissue, dramatically reducing post-operative pain, eliminating prolonged catheterization, and avoiding sexual side effects while maintaining effective obstruction relief.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If less-invasive mechanical methods like prostatic stents are used, then procedural risk is reduced, but the stents migrate or become dislodged reducing treatment effectiveness

Engineering Contradiction:
Improveprocedural simplicityVSAvoidstent position stability
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent employs anchoring elements that are preliminarily designed to secure the stent within the prostatic tissue. These anchoring features are integrated into the stent structure before deployment and engage with the prostate tissue during implantation, preventing migration or dislodgement while maintaining the minimally invasive nature of the procedure.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The stent incorporates composite structural features combining the expandable framework with integrated anchoring elements. This composite design allows the stent to be both minimally invasive in delivery and stable in position, as the anchoring components work together with the expandable structure to secure the device within the prostate while maintaining procedural simplicity.

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 solution effectively maintains urethral patency, reduces the risk of complications like encrustation and migration, and provides long-term relief from urinary retention by expanding the urethral cross-sectional area while minimizing tissue irritation.

Implementation Method 1

the expander structure is formed of a shape memory alloy and has a transition temperature which is above ambient temperature, but below body temperature

Methodology Applied
Scientific EffectShape memory alloy: Shape Memory Alloy

Implementation Method 2

said part radially widening at a transition temperature, which is above ambient temperature, but below body temperature

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3116583B1Indwelling body lumen expander
Publication Date: 2024.03.06 THE BOARD OF TRUSTEES OF THE LELAND STANFORD JUNIOR UNIV
  • EP3116583B1 patent drawingFigure 1A
  • EP3116583B1 patent drawingFigure 1B~1C
  • EP3116583B1 patent drawingFigure 2~4B

AI summary

Indwelling body lumen expanders which allow for the maintenance and patency of a body lumen, such as the prostatic urethra to relieve urethral obstruction, are described. Because the one or more expanders are configured to be relatively larger in diameter than the diameter of the body lumen, the expanders may become invaginated into the lumen wall thus enabling the prostheses to avoid fluid exposure which in turn prevent the prostheses from becoming encrusted or calcified.