Driving Handle Spiral Motion Converts Rotation to Linear Force for Implant Recapturing
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Solution Overview
Problem
The recapturing of larger heart valve prostheses is challenging due to the smaller inner diameter of the sheath tube, resulting in high resistance and difficulty in pulling the implant back into the body during the recapturing process.
Innovation Solution
A driving handle with a movable barrel that spirals along a fixing barrel, converting rotational motion into linear motion to drive sliders and pistons synchronously, facilitating the smooth pulling of the recapturing net and implant into the catheter sheath by applying a large longitudinal force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the recapturing net and implant are pulled into the catheter sheath directly, then the recapturing operation can be completed, but the resistance is relatively large and the pulling force required is relatively high
Solution Approach 1:
The patent introduces an intermediate expansion mechanism where the recapturing net is expanded within the catheter sheath to capture the implant, then contracted to facilitate retrieval. This intermediary expansion/contraction process reduces the direct pulling resistance by distributing the force through the net's structural transformation rather than direct linear pulling.
Solution Approach 2:
The recapturing net transitions from a contracted state during insertion to an expanded state for implant capture, then back to contracted state for retrieval. This dynamic state change allows the system to adapt its mechanical properties - expanded state provides high capture capability while contracted state reduces profile for easy retrieval through the catheter sheath.
2Reliability
If a recapturing apparatus with sheath tube and recapturing tube is used, then the implant can be captured and pulled back, but the inner diameter of the sheath tube is smaller making it difficult to accommodate larger implants
Solution Approach 1:
The recapturing apparatus is divided into functional segments: the catheter sheath for access, the recapturing net for implant engagement, and the delivery system for positioning. This segmentation allows each component to be optimized independently - the net can be sized to match the implant while the sheath maintains a consistent smaller profile.
Solution Approach 2:
The recapturing net is nested within the catheter sheath during insertion and retrieval, similar to nested dolls. The net expands beyond the sheath only when needed for implant capture, then returns to its nested state for retrieval. This nesting principle allows the system to accommodate large implants during capture while maintaining a small profile during transit through the vasculature.
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
Reduces the difficulty of the recapturing operation by minimizing resistance and allowing for efficient retrieval of implants by converting rotational motion into linear motion, making it easier to pull the recapturing net and implant into the catheter sheath.
Implementation Method 1
the movable barrel is configured to move spirally along the fixing barrel during at least a portion of a stroke to drive the first slider and the second slider to move synchronously and linearly along the tube passage
Data Source
AI summary
The present disclosure provides a driving handle, an apparatus and a method for recapturing an implant. The driving handle for recapturing an implant comprises: a first slider and a second slider, the first slider and the second slider being distributed in a longitudinal direction; a fixing barrel which defines a tube passage that receives the first slider and the second slider; a movable barrel which sleeves on the fixing barrel; wherein the movable barrel is configured to move spirally along the fixing barrel during at least a portion of a stroke to drive the first slider and the second slider to move synchronously and linearly along the tube passage. The present disclosure can alleviate the technical problem of difficult recapturing operation due to relatively high resistance when recapturing the implant.