Detachable Plastic Insulating Insert for Cost-Effective Resectoscopes

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Solution Overview

Problem

Existing resectoscopes face challenges in reducing the cost and thickness of insulation inserts while ensuring durability and reprocessability, particularly due to the use of high-performance ceramics like silicon nitride, which are expensive and prone to fragility.

Innovation Solution

The development of a detachable insulating insert made from thermally stable plastics, such as fluoropolymers or cycloolefin copolymers, which is securely fastened to the resectoscope shaft using various connection means, allowing easy replacement and cleaning, and featuring a hollow section for instrument passage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ceramic insulating inserts are used, then insulation reliability is improved, but manufacturing cost increases and wall thickness must be increased to reduce fragility

Engineering Contradiction:
Improveinsulation reliabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies the disposable principle by designing the insulating insert as a single-use component that is discarded after one sterilization cycle. This allows the use of cheaper plastic materials instead of expensive ceramics, while the disposable nature compensates for the lower durability. The insert is intentionally designed with limited reprocessing capability to enable cost-effective manufacturing through injection molding of thermoplastics.

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

Solution Approach 2:

The patent changes the material parameter from ceramic to thermoplastic, which fundamentally alters the manufacturing approach. This material substitution enables injection molding processes, reducing manufacturing cost while accepting thinner wall designs. The parameter change also shifts the operational model from reusable to single-use, resolving the contradiction between reliability and manufacturing cost.

Inventive Principle:
Principle #35Parameter changes

2Strength

If ceramic insulating inserts with thick walls are used, then fragility is reduced, but sterilization durability worsens and cost increases

Engineering Contradiction:
Improvefragility resistanceVSAvoidsterilization durability
Core Design Contradiction:
StrengthVSDuration of action of stationary object

Solution Approach 1:

The patent resolves the sterilization durability issue by adopting a disposable approach. Instead of designing for repeated sterilization cycles, the insert is intended for single use after one sterilization process. This eliminates the need for thick walls to withstand multiple autoclaving cycles, allowing thin-walled plastic designs that are sufficient for single-use applications.

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

3Duration of action of stationary object

If insulating inserts are made for multiple uses, then durability is improved, but reprocessability and cleaning accessibility worsen

Engineering Contradiction:
ImprovedurabilityVSAvoidreprocessability
Core Design Contradiction:
Duration of action of stationary objectVSEase of repair

Solution Approach 1:

The patent resolves the contradiction between durability and reprocessability by inverting the approach: instead of making the insert durable for repeated use, it is designed as a single-use component. This disposable nature actually improves reprocessability because the insert can be easily removed and discarded without requiring complex reprocessing procedures. The fastening means are designed for easy detachment, facilitating simple removal after one use.

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

4Reliability

If insulating inserts are securely fastened to the shaft, then reliability during operation is improved, but ease of replacement for cleaning worsens

Engineering Contradiction:
Improveoperational reliabilityVSAvoidease of replacement
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent applies the dynamics principle by designing a fastening system with two distinct states: a locked state during operation that ensures secure attachment and prevents displacement, and an unlocked state for replacement. The fastening means include detachable elements such as bayonet connections, snap-fit mechanisms, or threaded fasteners that can be quickly engaged and disengaged. This dynamic fastening system resolves the contradiction by providing both secure operation and easy replacement.

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

This design reduces material costs and thickness, enhances durability, and facilitates easy maintenance, while maintaining effective electrical insulation and supporting precise instrument guidance during electrosurgical procedures.

Implementation Method 1

thermostable plastics are particularly preferred. Thermostable plastics are able to withstand the high temperatures generated at the distal tip of the resectoscope without damage

Methodology Applied
Scientific EffectThermal resistance: Thermal Insulation

Implementation Method 2

the insulating insert is designed to be electrically non-conductive, i.e., electrically insulating. This ensures the isolation of the active electrode from the conductive resectoscope shaft

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Data Source

PatentEP3692938B1Releasable insulating insert for use in resectoscope
Publication Date: 2026.05.20 OLYMPUS WINTER & IBE GMBH
  • EP3692938B1 patent drawingFigure 1~2
  • EP3692938B1 patent drawingFigure 3~5
  • EP3692938B1 patent drawingFigure 6~8B

AI summary

The invention relates to an electrically insulating insert for detachable connection to the distal end region of a resectoscope shaft, characterized in that the insulating insert has a hollow section with an elongated cavity for passing through instruments and that the insulating insert has fastening means for detachable connection to the resectoscope shaft. Furthermore, the invention also relates to an electrode instrument connected to this insulating insert and to a resectoscope comprising this instrument.