Pusher-Engaged Catheter for Variable Cutting Diameter
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Solution Overview
Problem
Conventional catheters with a cutting diameter of up to 2 mm struggle to effectively cut objects in body lumens larger than 2 mm due to their standardized design.
Innovation Solution
A catheter system featuring a rotatable drive shaft, cutting member, and a pusher mechanism that introduces a bend to the distal portion, allowing for a larger cutting diameter by engaging with a pusher that includes a bent portion and elongated wires to navigate and guide the catheter to target positions within the body lumen.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional standardized catheter with a fixed cutting diameter of up to 2 mm is used, then the catheter structure is simple and easy to manufacture, but it cannot effectively cut objects in body lumens larger than 2 mm
Solution Approach 1:
The catheter employs a pusher mechanism that can be extended or retracted to dynamically change the cutting diameter. When the pusher is extended, it increases the effective cutting diameter beyond the standard 2 mm limitation, allowing the catheter to adapt to larger body lumens while maintaining a relatively simple base structure
Solution Approach 2:
The catheter is divided into functional segments including the main catheter body and a separate pusher component. This segmentation allows the pusher to be independently controlled and positioned, enabling variable cutting diameter adjustment without redesigning the entire catheter structure
2Adaptability or versatility
If the cutting diameter is increased to accommodate larger body lumens, then the catheter can remove objects from larger vessels, but the catheter structure becomes more complex
Solution Approach 1:
The pusher mechanism is nested within the catheter structure, with the pusher rod housed inside the catheter body. This nesting allows the extended cutting diameter functionality to be integrated within the existing catheter form factor without proportionally increasing overall device complexity
Solution Approach 2:
The pusher mechanism serves multiple functions: it extends the cutting diameter for larger lumens, provides additional pushing force during object removal, and can be retracted to restore the standard cutting diameter. This multi-functionality justifies the added structural complexity by delivering multiple benefits from a single mechanism
Data Source
AI summary
A catheter for removing an object in a body lumen includes an outer tube, a shaft surrounded by the tube, a cutting member connected to the shaft to be rotated with respect to a rotation axis, a guide wire tube attached to the outer tube and having a first lumen for a guide wire and second lumens, a metal member attached to the wire tube, a part of the metal member surrounded by the member, a distal tip attached to the wire tube and having a third lumen communicating with the first lumen, and a pusher extending along the shaft, connectable to the distal tip or the metal member, and including wires that can pass through the second lumens. The pusher causes the cutting member to move toward a first surface of the body lumen when contacting an opposite second surface of the body lumen.