Arthroscopic knee surgery tool design and materials selection

Stiffness scales as cube of diameter; slender surgical tools lose stiffness rapidly. Tom proposed single-crystal sapphire (60 Msi stiffness, ~2× steel) and color-coded ruby variants to a medical company; not adopted.

One of you was working on micro-catheters? I should have brought my micro-catheter stainless steel piece. Does anyone have a parent or grandparent that has a stent in their heart? How do they get it in? They take one of the arteries in your leg, and they go in with this long stainless steel Teflon-coated tube or wire, and they're taking flash x-rays so they can see. They put a little bit of barium on the tip so they can see exactly where it is in your arteries. They're taking x-ray movies while they're doing this. This has been a great boon for the radiology doctors putting stents in. It used to be the surgeon did open-heart surgery. Now these guys do this much less invasive stuff. The first one they put in is a guide wire, and then they use that like a little trolley wire to bring other things in, and they eventually put the stent in.