Stretch Resistant Embolic Coil Delivery System
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Solution Overview
Problem
Existing catheter-based systems for deploying embolic coils within the human body face challenges in accurately placing and releasing stretch-resistant coils in tortuous vasculature, particularly in the brain, due to limitations in detachment mechanisms and coil stability during deployment.
Innovation Solution
A vascular occlusive embolic device deployment system featuring a flexible catheter, a pusher member with a lumen, and a stretch-resistant member attached to the coil, utilizing an engagement member with an aperture and a detachment member to securely hold and release the coil at a predetermined site within a vessel, ensuring precise placement and minimizing coil stretching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a stretch-resistant embolic coil is used to maintain structural integrity during delivery, then coil stability is improved, but the coil cannot be accurately released at the target site
Solution Approach 1:
The system divides the embolic coil into two functional segments: a stretch-resistant portion (maintained in its original configuration) and a compliant portion (capable of stretching). This segmentation allows the coil to maintain structural integrity during delivery while enabling accurate release at the target site through the compliant section's ability to deform and engage with the delivery catheter's release mechanism
Solution Approach 2:
Different portions of the embolic coil are given different mechanical properties: the proximal portion is made stretch-resistant to maintain stability during delivery, while the distal portion is made compliant to enable accurate release and positioning at the target site. This local differentiation of material properties resolves the contradiction between overall stability and precise placement
2Ease of operation
If conventional detachment mechanisms are used to release the coil, then release is achieved, but coil position accuracy deteriorates due to stretching
Solution Approach 1:
The detachment mechanism is designed to interact specifically with the compliant distal portion of the coil rather than the entire coil structure. This localized interaction allows the release mechanism to function effectively while the stretch-resistant proximal portion maintains the coil's overall position accuracy and prevents unwanted stretching during the release process
3Ease of operation
If the coil is made compliant to facilitate release, then detachment is easier, but coil structural integrity deteriorates
Solution Approach 1:
The embolic coil is segmented into stretch-resistant and compliant portions, allowing the compliant section to facilitate easy detachment while the stretch-resistant section maintains structural integrity. This segmentation enables both easy operation and strength to coexist in different parts of the same device
Solution Approach 2:
Different mechanical properties are applied locally to different portions of the coil: the distal portion is made compliant to facilitate detachment, while the proximal portion maintains stretch-resistance to preserve structural integrity. This local quality differentiation resolves the contradiction between ease of detachment and structural strength
Data Source
Figure 1
Figure 1A
Figure 2A~2C
AI summary
A medical device for placing an embolic device at a predetermined site within a vessel of the body including a delivery catheter and a flexible pusher member having a lumen therethrough and being slidably disposed within the lumen of the catheter. A stretch resistant embolic device is retained within the delivery catheter by a mechanical interlocking mechanism which includes an engagement member which is slidably disposed within the pusher member and extends through a retaining ring at the proximal end of the embolic device. A detachment member extends through an aperture at the distal end of the engagement member thereby locking the embolic device onto the engagement member. The engagement member engages a retaining ring on the embolic device. When the embolic device is advanced to the predetermined site within the vessel, the detachment member is withdrawn from the aperture to thereby release the embolic device at the treatment site.