Endoscopic Instrument Shaft Nesting for Minimally Invasive Access

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Solution Overview

Problem

Existing endoscopic instruments for minimally invasive procedures, such as ureterorenoscopy, face challenges in reducing shaft diameter while maintaining functionality and improving visibility and control, particularly in the use of fluid channels and mechanical manipulation.

Innovation Solution

An endoscopic instrument with a tubular shaft that incorporates multiple electrical, mechanical, and optical lines within a fluid channel, allowing for a smaller diameter and enhanced functionalities, featuring a handling device with a Y-shaped grip for precise control and a guide roller system for bending the shaft without joints, along with a sealing mechanism to maintain fluid integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a conventional endoscopic instrument design is used, then the shaft can accommodate multiple functional lines, but the shaft diameter becomes too large for minimally invasive procedures

Engineering Contradiction:
Improveshaft diameterVSAvoidfunctionalities
Core Design Contradiction:
Volume of moving objectVSAdaptability or versatility

Solution Approach 1:

The patent implements nesting by placing multiple functional lines (irrigation line, suction line, working channels, electrical lines) inside the fluid channel lumen. The fluid channel acts as a container that houses these auxiliary lines, allowing them to share the same spatial pathway without increasing the overall shaft diameter. This nested arrangement enables minimally invasive insertion while maintaining full functional versatility.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The fluid channel serves multiple functions simultaneously: it acts as a conduit for irrigation fluid delivery, a pathway for returning fluid and debris via suction, a housing for multiple working channels and lines, and a structural component of the shaft. This multi-functionality reduces the need for separate dedicated channels for each function, thereby minimizing the shaft diameter while maximizing adaptability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Object-affected harmful factors

If the shaft diameter is reduced for minimally invasive procedures, then tissue trauma is reduced, but the available cross-section for functional lines is limited

Engineering Contradiction:
Improvetissue traumaVSAvoidavailable cross-section
Core Design Contradiction:
Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The patent employs nesting to maximize the utilization of the limited cross-sectional area. By placing working channels, electrical lines, and fluid pathways inside the fluid channel lumen, the design achieves high functional density within a small cross-section. This allows the shaft to remain thin for minimally invasive insertion while accommodating all necessary functional elements.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent transitions from a two-dimensional planar arrangement of channels to a three-dimensional nested configuration. The fluid channel lumen provides a volumetric space that can accommodate multiple lines running parallel or concentrically, effectively utilizing the third dimension (radial depth) to increase functional capacity without increasing the external shaft diameter.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If multiple lines are routed through separate channels, then each line is protected, but the shaft diameter increases

Engineering Contradiction:
Improveline protectionVSAvoidshaft diameter
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent protects multiple lines by nesting them within the fluid channel lumen, which acts as a protective outer sheath. Individual lines such as the irrigation line, suction line, and working channels are housed within this common protective enclosure, shielding them from external damage while maintaining their functional integrity. This approach provides reliable protection without requiring separate external channels for each line.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent merges the protective function with the fluid transport function by using the fluid channel wall itself as the protective barrier for the nested lines. Instead of providing separate protective sheaths for each line, the design combines multiple protection roles into a single unified structure, reducing the overall shaft diameter while maintaining line reliability.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of operation

If a fluid channel is routed through the shaft, then fluid management is improved, but the shaft cross-section is reduced for other lines

Engineering Contradiction:
Improvefluid managementVSAvoidcross-section for lines
Core Design Contradiction:
Ease of operationVSArea of stationary object

Solution Approach 1:

The patent resolves this contradiction by nesting other functional lines inside the fluid channel lumen. The fluid channel serves as the outer container that provides excellent fluid management capabilities, while simultaneously housing the working channels, electrical lines, and other functional elements within its interior space. This nested configuration allows the fluid channel to occupy the full cross-section for optimal fluid flow while other lines share the internal volume without requiring additional external space.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP3876816B1Endoscopic instrument
Publication Date: 2025.07.30 RICHARD WOLF GMBH
  • EP3876816B1 patent drawingFigure 1~2a
  • EP3876816B1 patent drawingFigure 2b~3a
  • EP3876816B1 patent drawingFigure 3b~3c

AI summary

The present disclosure relates to an endoscopic instrument (1) for inserting into a body of a patient, wherein the instrument (1) has a tubular shaft (3) which is coupled or can be coupled to a handling device (5, 135) and at least two electrical, mechanical and/or optical lines (11, 13, 15) extending through the shaft (3). The handling device (5, 135) has a housing (23) which has two limbs (141, 143) at a proximal end, said limbs being arranged obliquely with respect to one another and having a bearing surface (145), wherein at least one of the lines from one of the limbs (11, 13, 15, 19, 57, 59, 65, 67, 123, 181) is guided outwards from one of the limbs (141, 143) of the handling device (5, 135)