Dissolvable Glass For Bone Repair 168
gpronger writes "Sticks and Stones May Break My Bones, but Glass Will Certainly Mend Them! The old schoolyard ditty may be changed to reflect developments using metallic glass that will dissolve in situ instead of the traditional stainless steel or titanium hardware, which require removal by surgery once the bone has healed. Physics World reports that researcher Jörg Löffler at ETH Zurich has created an alloy of 60% magnesium, 35% zinc, and 5% calcium, molded in the form of metallic glass. Through rapid cooling, the alloy forms a molecularly amorphous glass that slowly dissolves over time, supporting the injury long enough for healing, then slowly dissolving away."
I'm involved in something closely related. (Score:5, Interesting)
My group is cooperating with a startup that makes, among other things, glass microbeads covered with nanoparticles of whose composition I am not allowed to speak. These nanoparticles cause bone cell growth. In fact, they cause stem cell differentiation into osteoblasts, which I think is beyong cool. The glass slowly dissolves in the body and the bone remains. Our hypothesis (backed by some experimental data) is that these beads will restore fractured bones, such as spinal vertebrae, to patients with extreme osteoporosis.
Rarely have I wished success to a company, as in this case. Perhaps seeing my aunt succumb to multiple spinal fractures scared the shit out of me.
It won't replace casting (Score:5, Interesting)
Unlike in a certain X-men movie, this "metallic glass" is NOT going to be injected into living human bodies while molten. It'll be carefully forged in a factory into parts that are currently made out of steel or titanium : various plates, screws, and other orthopedic hardware. For injuries that require surgery, orthopedic surgeons would use these metallic glass parts instead of what they currently use.
The problem is obvious : it's doubtful that this alloy will be as strong as steel or titanium, and so the screws or plates would have to be thicker and heavier to have the same strength. There's an obvious tradeoff : do you make a bigger incision and drill out bigger holes in the bone to use this dissolvable metallic glass, or do you use conventional hardware? Also, undoubtedly there will be decades of debate over whether the trace minerals leached into the body cause harm or not.
Bottom line : even if this technology turns out to be safe and effective and is approved for use, it will probably be decades until it is used most of the time.
Re:end to casts? (Score:5, Interesting)
Casts are annoying; but they are dirt cheap, can be performed with comparatively minimal training, and are pretty low risk. For bone breaks that are easily accessible and not too complicated, they are going to be hard to dislodge.
This stuff would, if it works, turn a two surgery process(one to implant, one to explant) for dealing with nastier sorts of bone breaks into a one surgery process. That would be a win. Turning a zero surgery process into a one surgery process would be a major loss.
Save the whales! (Score:1, Interesting)
"Metallic Glass", you say? Can transparent aluminum [wikipedia.org] be far behind?
Re:It won't replace casting (Score:3, Interesting)
Not necessarily, one of the biggest problems with metallic inserts is that they are so much stronger than the bone that they can occasionally cause secondary breaks. If this compound was closer to actual bone in strength and flexibility, there may be less of a trade off than you think.
Re:end to casts? (Score:4, Interesting)
Yep. I was going to comment that I have a 10" piece of titanium in my leg from a motorcycle accident, and at my 1-year followup appointment, there was no talk of removing it. I believe that these days they tend to leave the hardware in unless it's causing problems.
you don't know the topic (Score:2, Interesting)
certain areas of the world are naturally deficient in certain necessary elements, like iodine. other areas are naturally high in certain dangerous elements, like arsenic. it doesn't matter how much good nutrition they get from the foodstuffs of their countryside, it doesn't even matter how rich they are. if the surrounding countryside doesn't have the element (or too much of it), it doesn't have the element (or too much of it). you need a technological response to the problem, regardless of socioeconomics or intent to eat a well-balanced diet
http://en.wikipedia.org/wiki/Iodine_deficiency#Local_impact [wikipedia.org]
"Iodine deficiency has largely been confined to the developing world for several generations, but reductions in salt consumption and changes in dairy processing practices eliminating the use of iodine-based disinfectants have led to increasing prevalence of the condition in Australia and New Zealand in recent years. A proposal to mandate the use of iodized salt in most commercial breadmaking is expected to be adopted in 2009."
Re:It won't replace casting (Score:5, Interesting)
Re:end to casts? (Score:3, Interesting)
Possibly, but I doubt you'd regain use of the limb while it heals though. Such a thing is nothing new though.
I fell down a flight of stairs in 2001 and broke my leg pretty severely. Compound fracture in 5 places. I ended up having to get a plate and screws added to that leg (along with one big screw to prevent me from turning my ankle during this time - that one was removed later by the rest of the hardware is still in there).
I only wore a cast for a week. For the rest of the time I was given one of those strap on boot things, but was generally allowed to take it off whenever I wanted. For showers definately, but after asking the doctor he said it was fine just to take it off while sitting on the couch watching TV if I wanted.
Basic thing was that the plate and screws were in there holding everything together. No cast was really needed and the leg would heal fine. However, while they would hold it together, they were not nearly as strong as actual bone would be, and so if I started walking on it eventually the stress on the metal would cause it to warp and break.
This could be the same way. Strong enough to hold the bones together without a cast, but not strong enough to still use the limb as you normally would.
why the negativity? (Score:2, Interesting)
i'm just brainstorming potential other uses for this dissolving glass. i don't understand the basis for your opposition to the idea on nothing other than "food should be nutritious" when clearly in some areas of the world, food alone simply can't deliver proper nutrition and technology is required to give people proper nutrition
its just an idea. there's a million reasons why subdural implants of time release minerals could be unworkable. but your particular reason about medical personnel doesn't fly: poor rural people get vaccinated by travelling medical groups all the time. if they aren't eating artificially dosed foods like their city brethren, a subdural slowly dissolving mineral boost that lasts a year could dramatically improve lives for very little cost
you really think the idea should be discarded out of hand because you believe (erroneously) that food alone is the solution?
Why this is important for the US market. (Score:2, Interesting)
I engineer orthopaedic implants, and one of the things that is very interesting when considering design and excecution of implants is the culture of the physicians who will be using them.
Physicians who train in different countries (or time periods for that matter) have various preferences on what approaches they use and how they utilize certain devices. What is interesting about this case is that European surgeons are more likely to take hardware OUT of the patient after the fracture is resolved.
This is in contrast to US surgeons who tend to leave everything IN, supposedly to minimise the risk of second surgical exposure. Which technique is correct is up for debate, due to issues like infection rates and stress shielding, but this technology allows the best of both worlds.
This would not replace casting, for reasons mentioned above, but also because casting alone is only used on non-displaced fractures (or displace fractures that can be easily be aligned again).
Of even more interest is the mechanical characteristics of this material. Fracture plates that have moduli closer to bone don't produce as much stress sheilding, which causes the load path to run primarily through the plate and not the bone. Though this sounds like a good idea, bone relies on strain (which it sees due to stress applied and young's modulus) to signal bone remodeling. Too much shunting of load and the bone atriphies, making it likely to break again. These "absorbable" technologies usually produce a more compliant device, which is good for this. However, there is also the issue of the device breaking down and loosing rigidity before the bone can fully support load.
This idea has been done before, it will be interesting to see how this one pans out.