Stent Delivery System with Independent Retraction Controls
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Solution Overview
Problem
Current stent delivery systems lack precise control and flexibility during stent deployment, particularly for longer stents, due to limited control mechanisms and potential for uneven or rapid deployment, which can result in incorrect placement and increased deployment time.
Innovation Solution
A stent delivery system featuring three independent controls: a thumbwheel, a thumb lever, and a pull ring, allowing for different retraction ratios and speeds, enabling precise and dynamic control of the outer jacket for controlled stent deployment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single control mechanism is used for jacket retraction, then the device complexity is reduced, but the control precision and deployment accuracy deteriorate
Solution Approach 1:
The delivery system divides the single control function into three separate control mechanisms (thumbwheel, thumb lever, and pull ring), each capable of independently retracting the outer jacket. This segmentation allows the physician to select different controls for different deployment scenarios, thereby improving deployment accuracy without requiring a single complex control mechanism
Solution Approach 2:
The system provides dynamic control by allowing the physician to switch between different retraction mechanisms during the deployment process. The thumbwheel offers fine control for initial positioning, the thumb lever provides intermediate control, and the pull ring enables rapid retraction if needed. This dynamic adaptability improves deployment accuracy while keeping each individual control mechanism relatively simple
2Ease of operation
If manual control of the inner member is used during deployment, then the ease of operation is reduced, but the control precision improves
Solution Approach 1:
The system merges the control of the inner member with the outer jacket retraction controls. When the physician actuates any of the three retraction mechanisms (thumbwheel, thumb lever, or pull ring) to retract the outer jacket, the inner member is simultaneously controlled to remain stationary or move in a coordinated manner. This merging eliminates the need for separate manual control of the inner member while maintaining positioning accuracy through the integrated control mechanism
3Ease of operation
If the jacket and inner member are freely movable relative to each other, then the ease of operation is improved, but the reliability of controlled deployment deteriorates
Solution Approach 1:
The system incorporates a locking mechanism that is engaged by default during the delivery and positioning phases, preventing unintended movement between the jacket and inner member. The physician must deliberately actuate one of the three retraction controls to release the lock and enable controlled retraction. This preliminary locking action ensures reliable controlled deployment while maintaining ease of operation through simple deliberate activation
Data Source
AI summary
One preferred embodiment includes a stent delivery system including a retractable sheath and an outer stability sheath. The stability sheath freely rotates relative to the retractable sheath, relieving compression forces caused by twisting of stability sheath in when in a tortuous conformation.