Prostatic Stent Tactile Feedback Positioning Without Imaging

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Solution Overview

Problem

Existing prostatic stents and detachable catheter apparatuses struggle with correct positioning during insertion and prevent upward and downward migration within the urethra, often requiring imaging means like endoscopy or transrectal ultrasonography for accurate placement and face issues with stent migration.

Innovation Solution

The apparatus features expandable members with flexible tongues on both the proximal and distal tube sections that provide tactile feedback for correct positioning and prevent migration by abutting against the urinary sphincter and veru montanum, respectively, using a sheath to control tongue expansion and a flexible connecting mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an expandable member (balloon or Malecot) is used to prevent upward migration, then upward migration is reduced, but correct positioning cannot be reliably achieved without imaging means

Engineering Contradiction:
Improveprevention of upward migrationVSAvoidpositioning accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent introduces tactile feedback through the expandable member's interaction with the sphincter. The operator can feel when the expandable member abuts against the sphincter, providing direct feedback for correct positioning without requiring imaging means. This resolves the contradiction by making positioning detectable through tactile sensation while maintaining the migration prevention function.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The expandable member serves dual functions: it prevents upward migration through its expansion against the sphincter, and simultaneously provides positioning feedback to the operator. The structure itself performs both the containment function and the signaling function, eliminating the need for separate imaging equipment.

Inventive Principle:
Principle #25Self-service

2Ease of operation

If a detachable catheter apparatus is used for insertion, then insertion is facilitated, but stent migration (upward and downward) occurs after insertion

Engineering Contradiction:
Improveinsertion easeVSAvoidstent positioning stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent divides the stent into two separate tube sections (proximal and distal) connected by a flexible connection. Each tube section has its own expandable member that prevents migration in opposite directions. This segmentation allows the stent to be inserted as a complete apparatus while providing bidirectional migration prevention through distributed anchoring points.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies expandable members at specific locations on each tube section to address local migration tendencies. The proximal tube section's expandable member prevents upward migration, while the distal tube section's expandable member prevents downward migration. This localized approach ensures stability throughout the entire stent structure.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If imaging means (endoscopy or ultrasonography) are used for positioning control, then positioning accuracy is improved, but device complexity and cost increase

Engineering Contradiction:
Improvepositioning accuracyVSAvoidinsertion apparatus complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex imaging feedback systems with simple tactile feedback through the expandable member's abutment against the sphincter. The operator directly senses correct positioning through tactile contact, eliminating the need for endoscopy or ultrasonography equipment while maintaining reliable positioning accuracy.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent uses a simple, disposable expandable member structure that provides positioning feedback without requiring expensive, complex imaging equipment. The tactile feedback mechanism is inherently simple and does not necessitate costly technological additions to the insertion apparatus.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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

Enables correct positioning of the stent using tactile feedback without imaging, preventing upward and downward migration, ensuring stable placement and normal urinary sphincter function.

Implementation Method 1

each of said tongues being arranged to be elastically biased towards a radial and outward position

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

said expansion and/or collapse controlling means comprise a sheath adapted to enclose said distal part of said proximal tube section and constrain all tongues in a collapsed position

Methodology Applied
Scientific EffectMechanical constraint: Mechanical Force

Implementation Method 3

said flexible connecting means having a length allowing normal functioning of the urinary sphincter

Methodology Applied
Scientific EffectFlexibility: Elasticity

Data Source

PatentEP1887970B1A prostatic stent and a detachable catheter apparatus comprising the same
Publication Date: 2016.04.20 DEVONEC MARIAN
  • EP1887970B1 patent drawingFigure 1~2
  • EP1887970B1 patent drawingFigure 3
  • EP1887970B1 patent drawingFigure 4

AI summary

The present invention is an endo-prostatic stent and a detachable catheter apparatus including the same, allowing the correct positioning of the stent using tactile feed-back of the operator during insertion i.e. without the need for any imaging means like endoscopy or sonography.