Braided Vaso-Occlusive Member for Pushability and Soft Deployment
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Solution Overview
Problem
Existing braided embolic devices face challenges in achieving a balance between sufficient column strength for delivery and flexibility for deployment while maintaining softness to avoid vessel damage, often sacrificing stiffness or flexibility in manufacturing processes.
Innovation Solution
The development of braided embolic devices with novel braid patterns, such as 'two-over, one-under', 'two-over, two-under', 'three-over, one-under', and 'seven-over, one-under', which provide enhanced flexibility and softness by optimizing the orientation and arrangement of elongate members, combined with the use of marker filaments for improved radiopacity and stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional braid patterns are used, then manufacturing is simpler, but flexibility and softness are insufficient
Solution Approach 1:
The patent changes the braid pattern parameters from conventional one-over-one-under patterns to non-conventional patterns such as two-over-one-under, two-over-two-under, three-over-one-under, and seven-over-one-under. This parameter change in the braid structure allows the device to maintain manufacturing feasibility while significantly improving flexibility and softness by altering how filaments interweave and distribute mechanical stresses.
Solution Approach 2:
The patent combines different filament types including shape memory alloys, superelastic materials, and polymers in a composite braid structure. This composite approach allows the device to achieve both flexibility from polymer components and structural integrity from metal filaments, resolving the contradiction between ease of manufacture and operational flexibility.
2Strength
If device stiffness is increased for delivery, then pushability improves, but flexibility post-deployment deteriorates
Solution Approach 1:
The patent employs shape memory and superelastic materials that dynamically change their mechanical properties based on environmental conditions. During delivery, the device maintains higher stiffness for pushability, but upon deployment at body temperature, the materials transition to a more flexible state, automatically adapting to the different operational requirements without manual intervention.
Solution Approach 2:
The patent utilizes the temperature-dependent parameter changes of shape memory alloys and superelastic materials. The device is delivered in a constrained state with high column strength, then undergoes a parameter change when exposed to body temperature, transitioning to a flexible deployed state that conforms to vascular structures without requiring manual manipulation.
3Strength
If device stiffness is increased for delivery, then pushability improves, but risk of vessel damage increases
Solution Approach 1:
The patent employs materials that dynamically adjust their stiffness based on environmental conditions. The device is stiff during delivery to maintain column strength and pushability, but automatically becomes soft upon deployment at body temperature, eliminating the risk of vessel damage while maintaining delivery performance. This dynamic adaptation removes the need to compromise between delivery strength and safety.
Solution Approach 2:
The patent utilizes temperature-induced parameter changes in shape memory and superelastic materials to transition the device from a stiff delivery configuration to a soft deployed configuration. This parameter change ensures the device has sufficient column strength for delivery through the catheter system, then becomes compliant with vessel walls upon deployment, preventing vessel damage without sacrificing delivery capability.
4Ease of operation
If braid pattern is optimized for flexibility, then softness improves, but column strength deteriorates
Solution Approach 1:
The patent combines flexible polymer filaments with stiff metal filaments (shape memory alloys or superelastic materials) in a composite braid structure. The polymer provides flexibility and softness, while the metal filaments provide column strength, allowing the device to achieve both improved flexibility and maintained structural integrity simultaneously.
Solution Approach 2:
The patent uses non-conventional braid patterns with specific over-under sequences that optimize the distribution of mechanical loads. These parameter changes in the braid architecture, combined with material selection, allow the flexible components to provide softness while the structural components maintain column strength, achieving both flexibility and strength without compromise.
Data Source
AI summary
A braided vaso-occlusive member formed out of first plurality of filaments interwoven with a second plurality of filaments, wherein filaments of the first plurality are helically wound in a first rotational direction along an elongate axis of the braided member, and filaments of the second plurality are wound in a second rotational direction opposite the first rotational direction, such that filaments of the first plurality cross over and/or under filaments of the second plurality at each of a plurality cross-over locations axially spaced along the elongate axis of the braided member, wherein at each cross-over location, the filaments of the first plurality cross over at least two consecutive filaments of the second plurality, then cross under only a single filament of the second plurality, and then cross over at least two additional consecutive filaments of the second plurality.