Memory Metal Basket Clot Retrieval Without Vessel Occlusion
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Solution Overview
Problem
Current intravascular thrombus removal devices are ineffective in removing hard, organized blood clots and foreign bodies from the brain due to their design limitations, such as requiring vessel occlusion, failure to dislodge clots from vessel walls, and embolization of clot fragments during retrieval.
Innovation Solution
A deployable system comprising a pull wire with a distal body made of memory metal strips that can expand and collapse to capture and retrieve clots from within a catheter, allowing for safe and complete removal without occluding the vessel, using a method that involves laser cutting and shaping a single memory metal tube to form a basket-like structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current thrombus removal devices are used, then vessel occlusion is required to remove clots, but this increases the risk of further ischemia and vessel injury
Solution Approach 1:
The device employs a dynamic basket structure that can transition between compressed and expanded states. The basket is compressed during delivery through the catheter and then expanded at the target site to capture the clot, allowing effective clot removal without requiring proximal vessel occlusion.
Solution Approach 2:
The device is divided into distinct functional segments: a delivery catheter for navigation, a collapsible basket for clot capture, and a retrieval mechanism. This segmentation allows the clot removal function to be separated from the occlusion requirement, enabling safe retrieval without compromising vessel patency.
2Reliability
If current retrieval devices are used, then clot dislodgement from vessel walls is ineffective, but this requires more aggressive maneuvers that increase embolization risk
Solution Approach 1:
The basket is constructed from flexible memory metal strips that can conform to the clot structure and gently engage the clot surface. This flexibility allows effective dislodgement of clots from vessel walls without requiring aggressive maneuvers that could fragment the clot and cause embolization.
Solution Approach 2:
The device utilizes composite construction with memory metal strips providing both structural integrity and flexibility. The memory metal properties enable the basket to maintain its shape for effective clot engagement while remaining compliant enough to avoid clot fragmentation during retrieval.
3Productivity
If a deployable memory metal basket is used, then retrieval efficiency is improved, but device complexity increases
Solution Approach 1:
The memory metal basket utilizes self-expanding properties through its material characteristics. When released from the compressed state, the basket automatically expands to its functional configuration without requiring additional actuators or complex control mechanisms, maintaining simplicity while achieving efficient clot capture and retrieval.
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
Enables the safe and effective removal of hard clots and foreign bodies from intracranial vessels without occluding the vessel, reducing the risk of embolization and improving retrieval efficiency by using a deployable memory metal basket that can be easily maneuvered and expanded within a catheter.
Implementation Method 1
a distal body made of memory metal strips that can expand and collapse to capture and retrieve clots
Data Source
AI summary
Catheter-delivered endovascular medical devices are described. The devices may include a pull wire attached to a distal body. The distal body may be formed of a distal body outer body comprising a basket comprised of a plurality of cells defined by a plurality of basket strips and a distal body inner body located in the interior of the distal body outer body and comprising a plurality of distal braided mesh openings formed by a plurality of woven linear strands. The distal braided mesh openings may be smaller than the cells when the device is in the relaxed state. Methods of using and making the devices are also described.