3 ms·

> Clot retrievers and aneurysm closures for treatment of intracranial disease, and components for implantable drug delivery systems, are targeted areas of TiNi

> Clot retrievers and aneurysm closures for treatment of intracranial disease, and components for implantable drug delivery systems, are targeted areas of TiNi Alloy Company technology. Any news on this?

mhb 4y ago
I don't know - it's been decades. But the history of TiNi alloy is littered with ideas which seem like they could, potentially, take advantage of its unique properties but don't ultimately pan out due to cost, difficulty of fastening the material, need for a compliant element since the alloy only works in one direction. An interesting successful application was the Frangibolt - a non-explosive way of breaking bolts to separate components of an assembly in space.
- PaulDavisThe1st 4y ago
  A friend who is a material scientist told me about another interesting TiNi application. I don't recall the precise details, but some sort of medical "device" that only assumes its final configuration once inside the body. You can tune the temperature response of the alloy, and so this was made "small enough" to fit (maybe through blood vessels?) and after a short time would "expand" to its intended shape. Wish I could remember more.
  - SemanticStrengh 4y ago
    looks like a very promising field
  - mikewarot 4y ago
    You're probably thinking of stents[1], used to hold open clogged arteries. 1 - https://pubmed.ncbi.nlm.nih.gov/12955452/ https://pubmed.ncbi.nlm.nih.gov/12955452/
    - SemanticStrengh 4y ago
      Sounds amazing. Is it used in practice? I wonder if it could have uses for artificial hearts too
      - sanarothe 4y ago
        Yes used in practice! I do production support in this field. Nitinol is used in lots of vascular devices. At least in my company, they used it first in guidewires just for the super elasticity, as a torturous vessel may kink a steel wire. At first there were bare metal stents, steel and later CoCr alloy. But last 15 years or so we've gotten self expanding stents that use the shape memory effect to set the final diameter at body temperature during processing, then the Stent is collapsed down into a catheter delivery system. There are various designs for releasing the collapsed Stent into the vessel, but once there it springs open thanks to super elasticity and apposes (conforms) up to the vessel wall, where good apposition gives lower chance of thrombosis formation. There are lots of other devices too... embolic protection devices (niti frame with a net over it, to catch shmoo from flowing to brain during a carotid procedure ) And various heart repair devices. It's great for intervention devices because you can collapse a device down small enough to be advanced by radial or femoral artery access and let's you do things that would normally require cracking someone's chest open for heart surgery. But the material is finicky, and it could take a decade for a smelter to get their niti process worked out. A very small difference in alloy composition disproportionately affects the crystal structure transition temperature, which impacts whether device will behave in service conditions
        largbae 4y ago
        This right here is what HN is for. Thank you for sharing!!
mcphage 4y ago
My 6-year-old got a Nitinol device put into his heart to close a hole. They could make it small for insertion in a vein (artery?), then expand when it was in place.
- SemanticStrengh 4y ago
  That's facinating, any link on the procedure name?

mhb 4y ago

I don't know - it's been decades. But the history of TiNi alloy is littered with ideas which seem like they could, potentially, take advantage of its unique properties but don't ultimately pan out due to cost, difficulty of fastening the material, need for a compliant element since the alloy only works in one direction. An interesting successful application was the Frangibolt - a non-explosive way of breaking bolts to separate components of an assembly in space.

PaulDavisThe1st 4y ago
A friend who is a material scientist told me about another interesting TiNi application. I don't recall the precise details, but some sort of medical "device" that only assumes its final configuration once inside the body. You can tune the temperature response of the alloy, and so this was made "small enough" to fit (maybe through blood vessels?) and after a short time would "expand" to its intended shape. Wish I could remember more.
- SemanticStrengh 4y ago
  looks like a very promising field
- mikewarot 4y ago
  You're probably thinking of stents[1], used to hold open clogged arteries. 1 - https://pubmed.ncbi.nlm.nih.gov/12955452/ https://pubmed.ncbi.nlm.nih.gov/12955452/
  - SemanticStrengh 4y ago
    Sounds amazing. Is it used in practice? I wonder if it could have uses for artificial hearts too
    - sanarothe 4y ago
      Yes used in practice! I do production support in this field. Nitinol is used in lots of vascular devices. At least in my company, they used it first in guidewires just for the super elasticity, as a torturous vessel may kink a steel wire. At first there were bare metal stents, steel and later CoCr alloy. But last 15 years or so we've gotten self expanding stents that use the shape memory effect to set the final diameter at body temperature during processing, then the Stent is collapsed down into a catheter delivery system. There are various designs for releasing the collapsed Stent into the vessel, but once there it springs open thanks to super elasticity and apposes (conforms) up to the vessel wall, where good apposition gives lower chance of thrombosis formation. There are lots of other devices too... embolic protection devices (niti frame with a net over it, to catch shmoo from flowing to brain during a carotid procedure ) And various heart repair devices. It's great for intervention devices because you can collapse a device down small enough to be advanced by radial or femoral artery access and let's you do things that would normally require cracking someone's chest open for heart surgery. But the material is finicky, and it could take a decade for a smelter to get their niti process worked out. A very small difference in alloy composition disproportionately affects the crystal structure transition temperature, which impacts whether device will behave in service conditions
      - largbae 4y ago
        This right here is what HN is for. Thank you for sharing!!

mcphage 4y ago

My 6-year-old got a Nitinol device put into his heart to close a hole. They could make it small for insertion in a vein (artery?), then expand when it was in place.

SemanticStrengh 4y ago
That's facinating, any link on the procedure name?