Flexible Endoscope Insertion Tube Kink Resistance
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Solution Overview
Problem
Conventional endoscope designs are expensive, complex, and prone to catastrophic failure, with high failure rates and limited maneuverability due to their fragile nature and obstructive deflection wires.
Innovation Solution
An endoscope insertion tube featuring a braided shaft with a laminated thermoplastic housing and deflection wires positioned within the lumen, allowing for a smaller outer diameter and improved kink resistance, torque transmission, and steerability, while minimizing the risk of catastrophic failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional endoscope designs are used, then imaging and working channels can be housed, but the device becomes expensive, complex, and prone to catastrophic failure
Solution Approach 1:
The insertion tube is divided into multiple laminated sections with different durometers (hardness levels). Each section can be independently optimized for specific functions, allowing the overall system to achieve high reliability without requiring a completely complex monolithic design. The segmentation of the tube into proximal, middle, and distal sections with varying properties reduces the complexity of any single component while improving overall reliability.
Solution Approach 2:
The insertion tube employs a composite structure with multiple laminated layers of different materials and durometers. This composite approach allows combining the strengths of different materials to create a tube that is both reliable and simpler in individual component design, avoiding the need for expensive specialized materials in all sections.
2Ease of operation
If deflection wires are positioned within catheter walls to maximize lumen size, then lumen diameter is maximized, but the wire resists movement out of plane and creates whipping effect
Solution Approach 1:
Different sections of the insertion tube are given different local qualities through varying durometer values. The distal section has lower durometer for flexibility and steering, while proximal sections have higher durometer for stability. This local differentiation allows the tube to steer effectively without creating whipping effects, as each section is optimized for its specific functional requirements.
Solution Approach 2:
The insertion tube employs dynamic flexibility through its laminated structure, where different sections have different resistance to bending. This dynamic property allows the tube to adapt its stiffness along its length, enabling smooth steering movements without the rigid resistance that causes whipping effects in uniform structures.
3Ease of operation
If the insertion tube is made more flexible to improve maneuverability, then steerability improves, but the tube becomes more prone to kinking and catastrophic failure
Solution Approach 1:
Different sections of the insertion tube have different durometer values optimized for their specific locations. The distal section has lower durometer for flexibility and maneuverability, while proximal sections have higher durometer for kink resistance and structural integrity. This local quality differentiation resolves the contradiction by allowing flexibility where needed without compromising overall strength.
Solution Approach 2:
The laminated structure with varying durometers provides beforehand cushioning against kinking and catastrophic failure. The higher durometer proximal sections act as a protective buffer that prevents kinks from propagating distally, while the lower durometer distal sections maintain flexibility for maneuverability.
4Length of moving object
If a smaller outer diameter is used to minimize incision size, then percutaneous incision size is reduced, but the tube becomes more fragile and prone to failure
Solution Approach 1:
The insertion tube uses a composite laminated structure with multiple layers of different materials and durometers. This composite design allows the tube to maintain a small outer diameter while achieving high reliability through the synergistic combination of different materials, each contributing specific properties that prevent catastrophic failure.
Solution Approach 2:
The tube is segmented into multiple laminated sections that can independently absorb stresses and deformations. This segmentation prevents a single point of failure from causing catastrophic failure of the entire tube, allowing a small diameter design to achieve high reliability through distributed structural integrity.
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 provides superior kink resistance, pushability, and torque transmission, enabling enhanced maneuverability within anatomies and reducing the likelihood of catastrophic failure, allowing procedures to be completed without replacing the device.
Implementation Method 1
a thermoplastic laminate laminated to the at least a portion of the outer surface of the shaft
Implementation Method 2
with rheological properties that reduces the risk of catastrophic failure
Implementation Method 3
superior kink resistance, pushability, and torque transmission
Implementation Method 4
at least two gaps between the shaft and the liner, wherein the gaps define two deflection channels
Data Source
AI summary
An endoscope includes a handle connected to a flexible, steerable, kink-resistant insertion tube. An endoscope insertion tube may include a shaft, a lower durometer section proximate to a distal end of the shaft, and a higher durometer section positioned between the lower durometer section and a medium durometer section. The endoscope insertion tube may further include a fourth thermoplastic laminate section proximate to a proximal end of the shaft and having a higher durometer. A method of making an endoscope insertion tube may include inserting a mandrel with one, two, or more lateral slots and a liner into a shaft, wherein the liner is positioned between the mandrel and the shaft, bonding a bonded portion of the liner to an inner surface of the shaft, separating other portion(s) of the liner from the shaft, and inserting a first deflection wire in a gap between the shaft and the unbonded portion(s) of the liner.