Stent Delivery Catheter Living Hinge Retraction Control
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Solution Overview
Problem
Current stent delivery systems require delicate skill for deployment due to dynamic blood flow and the gradual resilient expansion of stents, which can lead to non-optimum positioning and reverse 'watermelon-seed' phenomenon, necessitating precise control of inner and outer catheter shafts.
Innovation Solution
A stent delivery system with a handle mechanism featuring a living hinge and pivot mount allows for precise control of the outer sheath translation through two distinct ranges of travel, enabling orthogonal actuation for initial deployment and longitudinal sliding for complete deployment, facilitating precise and rapid stent placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the outer sheath is retracted gradually to allow resilient stent expansion, then the stent can self-expand to a larger deployed size, but the reverse watermelon-seed phenomenon may occur causing the stent to push the outer sheath back proximally
Solution Approach 1:
The patent introduces an intermediary mechanism (the handle assembly with movable sheath and fixed shaft) that mediates between the physician's manual operation and the stent deployment process. This intermediary system translates simple proximal pulling motion into controlled sheath retraction while maintaining precise positioning capability, thereby resolving the contradiction between reliable gradual expansion and ease of operation.
2Measurement precision
If the physician holds both proximal hubs stationary during deployment, then the stent can be positioned accurately, but the operation requires delicate skill and precise coordination
Solution Approach 1:
The patent segments the deployment control into two independent components: a movable sheath for positioning and a fixed shaft for stability. This segmentation allows the physician to operate with only one hand holding the handle stationary while the other hand controls sheath retraction, thereby maintaining positioning accuracy while dramatically reducing operational complexity and skill requirements.
Solution Approach 2:
The handle assembly acts as an intermediary mechanism that decouples the physician's manual control from the dual-hub coordination problem. By providing a fixed reference point (stationary handle) and a controlled movement mechanism (movable sheath), the intermediary system transforms a complex two-handed coordination task into a simple one-handed operation, maintaining precision while improving ease of use.
3Manufacturing precision
If the inner shaft is held stationary during deployment, then the stent position can be controlled, but the system requires two-handed operation with independent hub control
Solution Approach 1:
The patent merges the control functions into a single integrated handle assembly where the fixed shaft and movable sheath are combined. This merging eliminates the need for separate independent hub controls, reducing device complexity while maintaining precise stent placement capability through the unified handle mechanism.
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
This mechanism allows for precise initial deployment and rapid complete deployment of the stent, reducing the risk of non-optimum positioning and enhancing the control over stent placement within the body vessel.
Implementation Method 1
A stent delivery system with a handle mechanism featuring a living hinge and pivot mount allows for precise control of the outer sheath translation
Implementation Method 2
A stent delivery system with a handle mechanism featuring a living hinge and pivot mount allows for precise control of the outer sheath translation through two distinct ranges of travel
Implementation Method 3
Upon deployment, the stents may resiliently self-expand to a larger deployed size
Data Source
Figure 1
Figure 2A~2C
Figure 3A~3D
AI summary
Various embodiments for a stent delivery device that utilizes a lost motion technique via a living connected to two cantilever arms for slow retraction of an outer sheath and an actuator member coupled to the two arms for fast retraction of the outer sheath during delivery of a self- expanding implantable device such as a stem or stent graft.