Nitinol Clot Retrieval Basket with Claw Mechanism
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Solution Overview
Problem
Current intravascular thrombus and foreign body removal devices are ineffective in removing hard, organized blood clots and foreign bodies from the brain due to their design limitations, such as requiring proximal vessel occlusion, failing to dislodge clots from vessel walls, and causing embolization of clot fragments.
Innovation Solution
A deployable system comprising a pull wire with a distal body having memory metal strips that expand to capture and encase clots, allowing for retrieval without proximal occlusion, featuring a claw mechanism to separate clots from vessel walls and a basket design to prevent embolization, manufactured using nitinol for biocompatibility and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If currently available thrombus removal devices (MERCI, PENUMBRA, SOLITAIRE, TREVO) are used, then device deployment is possible, but they fail to effectively remove hard organized thrombus and cause embolization of clot fragments
Solution Approach 1:
The distal body is divided into multiple functional segments: a claw mechanism with movable fingers for gripping and separating thrombus from vessel walls, a basket structure with radially extendable members for encasing thrombus, and memory metal strips for providing structural support and enabling expansion. This segmentation allows each component to perform its specific function effectively while working together to prevent embolization.
Solution Approach 2:
The device converts the harmful property of hard organized thrombus (which is difficult to remove) into a benefit by using the claw mechanism to grip and fragment the thrombus in a controlled manner, then encasing the fragments in the basket structure. This transforms the previously problematic hard thrombus into manageable pieces that can be safely retrieved without embolization.
2Reliability
If devices require proximal vessel occlusion for thrombus removal, then thrombus can be stabilized, but risk of further ischemia and vessel injury increases
Solution Approach 1:
The device extracts the necessary function of thrombus stabilization from the proximal occlusion approach. The claw mechanism and basket structure provide localized stabilization and containment of the thrombus at the distal site, eliminating the need for proximal vessel occlusion and thereby preventing associated ischemia and vessel injury.
Solution Approach 2:
The distal body with its claw and basket mechanisms serves as an intermediary device that provides thrombus stabilization and containment directly at the site of occlusion. This intermediary structure replaces the need for proximal balloon occlusion, allowing thrombus removal without the harmful effects of proximal vessel blocking.
3Ease of operation
If devices are made small and flexible to navigate tortuous vessels, then navigation capability is improved, but device strength to dislodge adherent thrombus is reduced
Solution Approach 1:
The device employs dynamic structures that can change configuration: the claw mechanism with movable fingers that can open for navigation and close for gripping, the basket members that can radially extend for thrombus encasement, and the memory metal strips that provide shape memory for expansion. These dynamic features allow the device to be flexible during navigation but strong during thrombus removal.
Solution Approach 2:
The device utilizes parameter changes in the form of shape memory alloy (Nitinol) properties. The memory metal strips and basket members can transition between compressed and expanded states, allowing the device to navigate tortuous vessels in a compact form while providing sufficient strength and surface area for dislodging and containing hard organized thrombus when expanded.
4Device complexity
If devices use open-ended design for thrombus entrapment, then device simplicity is maintained, but embolization of thrombus occurs
Solution Approach 1:
The device merges two functions into a unified structure: the claw mechanism for gripping and separating thrombus combines with the basket structure for encasing thrombus fragments. This merged design provides both the simplicity of an open-ended structure for navigation and the containment capability to prevent embolization during 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 safe, effective, and multi-use removal of hard clots and foreign bodies from intracranial vessels without causing further ischemia or vessel injury, with the ability to navigate tortuous paths and retrieve clots intact, reducing the risk of embolization.
Implementation Method 1
manufactured using nitinol for biocompatibility and flexibility
Implementation Method 2
manufactured using nitinol for biocompatibility and flexibility
Implementation Method 3
a distal body having memory metal strips that expand to capture and encase clots
Data Source
AI summary
A platform of devices for removing obstructions and other objects within a blood vessel or other interior lumen of an animal is provided. The system may be deployed in the lumen from a catheter(s) and the system includes a proximal hub, and a distal basket comprised of a plurality of cells. A number of different baskets designs are disclosed. Methods of manufacturing such baskets out of a single tube of a memory metal without the need for any welding, and methods of use are also disclosed.