Catheter Drive Assembly for Simultaneous Rotation and Reciprocation
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Solution Overview
Problem
Current tissue-removing catheters lack the capability to simultaneously rotate and reciprocate effectively, which is necessary for efficient removal of occlusive and stenotic tissue from body lumens, such as blood vessels, due to limitations in drive assembly design.
Innovation Solution
A drive assembly that includes a prime mover generating rotational force, a reciprocating rotor connected to the drive shaft, and a stator constraining the rotor's movement, allowing for simultaneous rotation and reciprocation of the tissue-removing element, enhancing tissue removal by combining cutting and shearing actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional drive assembly is used in tissue-removing catheters, then the structure is simpler, but the capability to simultaneously rotate and reciprocate the tissue-removing element is insufficient
Solution Approach 1:
The drive assembly employs a dynamic mechanism where the rotor can both rotate about its axis and reciprocate along the axis. The bearing projections on the stator interact with the race on the rotor to convert rotational motion into combined rotational and reciprocating motion, enabling the tissue-removing element to perform both cutting and shearing actions simultaneously
Solution Approach 2:
The patent introduces an intermediary mechanism consisting of the rotor, stator, bearing projections, and race. This intermediary system acts as a motion converter between the prime mover's pure rotation and the tissue-removing element's required combined rotation and reciprocation, resolving the contradiction between functional versatility and structural simplicity
2Productivity
If only rotation is provided to the tissue-removing element, then the drive assembly is simpler, but tissue removal efficiency is reduced
Solution Approach 1:
The drive assembly implements periodic reciprocating motion superimposed on continuous rotation. The rotor reciprocates back and forth along its axis while rotating, creating a periodic cutting action that enhances tissue removal efficiency by combining shearing and cutting mechanisms, thereby improving productivity despite increased structural complexity
3Adaptability or versatility
If a reciprocating rotor is added to the prime mover, then rotation and reciprocation capability is improved, but the device complexity increases
Solution Approach 1:
The patent merges the rotation and reciprocation functions into a single integrated rotor-stator assembly. The rotor simultaneously performs rotation about its axis and reciprocation along the axis, while the stator with bearing projections provides the mechanical constraint that enables this combined motion, reducing the need for separate mechanisms for each motion type
Data Source
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AI summary
A tissue-removing catheter includes a drive assembly operatively connected to a drive shaft to impart rotation and reciprocation to the drive shaft and thereby rotate and reciprocate a tissue-removing element of the catheter. The drive assembly includes a prime mover configured to generate a rotational drive force and a reciprocating rotor operatively connected to the prime mover to receive the rotational drive force. The rotor is also operatively connected to the drive shaft to impart rotation and reciprocation to the drive shaft. The drive assembly can include a stator configured to constrain rotation and reciprocation of the reciprocating rotor relative to an axis of the rotor. The rotor can define a race that extends around the rotor axis, and the stator can define one or more bearing projections that track through the race as the prime mover rotates the rotor about the rotor axis to drive reciprocation of the rotor.