Cannula Alignment via Elastic Biasing in Vascular Delivery
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Solution Overview
Problem
Existing delivery devices for vascular occluding devices, such as embolization coils, often result in improper alignment between the cannula and catheter port, leading to premature delivery and waste of the coil, cannula, and potentially the catheter, due to gaps between the distal cannula end and the longitudinal bore.
Innovation Solution
A delivery device featuring a cannula with a stability collet and an elastic member, such as a resilient spring or elastomeric expansion element, that biases the cannula distally relative to the stability collet, ensuring proper alignment and preventing premature delivery by maintaining contact with the catheter port.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the distal end of the cannula is positioned close to the catheter port to ensure proper alignment, then the alignment accuracy is improved, but the cannula may prematurely contact the catheter port causing improper delivery
Solution Approach 1:
The cannula is designed to be longitudinally movable relative to the stability collet, transitioning from a retracted position during assembly to a protruding position during delivery. This dynamic positioning allows the cannula to be pulled forward by the elastic member's restoring force, ensuring it protrudes sufficiently to enter the longitudinal bore while preventing premature contact that would cause improper delivery.
Solution Approach 2:
The elastic member is pre-loaded in a compressed state during assembly, storing potential energy that will be converted to kinetic energy during delivery. This preliminary action ensures that when the stability collet is attached to the catheter port, the elastic member automatically pulls the cannula forward to the correct protruding position, achieving proper alignment without manual intervention.
2Device complexity
If the cannula is held stationary relative to the stability collet, then the device structure is simpler, but the cannula cannot maintain proper alignment with the catheter port
Solution Approach 1:
The cannula is designed to be longitudinally movable relative to the stability collet, transitioning from a retracted position during assembly to a protruding position during delivery. This dynamic positioning allows the cannula to be pulled forward by the elastic member's restoring force, ensuring it protrudes sufficiently to enter the longitudinal bore while preventing premature contact that would cause improper delivery.
Solution Approach 2:
The elastic member is pre-loaded in a compressed state during assembly, storing potential energy that will be converted to kinetic energy during delivery. This preliminary action ensures that when the stability collet is attached to the catheter port, the elastic member automatically pulls the cannula forward to the correct protruding position, achieving proper alignment without manual intervention.
3Reliability
If the cannula protrudes far from the stability collet to ensure entry into the longitudinal bore, then the delivery reliability is improved, but the alignment accuracy with the catheter port deteriorates
Solution Approach 1:
The cannula is designed to be longitudinally movable relative to the stability collet, transitioning from a retracted position during assembly to a protruding position during delivery. This dynamic positioning allows the cannula to be pulled forward by the elastic member's restoring force, ensuring it protrudes sufficiently to enter the longitudinal bore while preventing premature contact that would cause improper delivery.
Solution Approach 2:
The elastic member provides continuous mechanical feedback by maintaining a constant restoring force that pulls the cannula forward. This feedback mechanism ensures the cannula automatically adjusts its position to protrude the optimal distance from the stability collet, achieving both sufficient protrusion for reliable delivery and proper alignment with the catheter port.
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
The elastic member ensures accurate alignment of the cannula with the catheter port, reducing waste and facilitating smooth delivery of the occluding device into the catheter, thereby improving the efficiency of the delivery process.
Implementation Method 1
an elastic member acting between the cannula and the stability collet. The elastic member biases the cannula distally relative to the stability collet
Implementation Method 2
the resilient spring may be a compression spring with a proximal spring end restricted by the longitudinal channel of the stability collet and with a distal spring end restricted by a stop on the cannula
Data Source
AI summary
A delivery device for delivering material into a catheter through a catheter port includes a cannula having a generally tubular shape and a distal end and a stability collet having a distal attachment portion configured to attach the stability collet to a catheter port. The stability collet has a longitudinal channel through which the cannula extends. The longitudinal channel is dimensioned to allow a longitudinal movement of the cannula in the longitudinal channel. The delivery device further includes an elastic member acting between the cannula and the stability collet. The elastic member biases the cannula distally relative to the stability collet. Thus, when the stability collet is attached to the catheter port, the cannula is urged toward the catheter port, thus reducing a risk of improper alignment between the cannula and the catheter port.