Thursday, February 26, 2009

What's Bone Cement-Part I

We get a lot of different questions from our patients about bone cement that is used to fix painful VCFs. While an exhaustive explanation is beyond the scope of this blog, I am going to answer some of the most common questions we get.

What is bone cement?
Also known as bone glue, the material we commonly call 'bone cement' is a polymer called polymethylmethacrylate, or PMMA for short. This is made from mixing a powder and a liquid together in the operating room. This forms a paste that quickly hardens up in about 15-25 minutes. It starts out thin like cream, then gets thicker, like toothpaste by the time it's used in the body. Then it gets as thick as modelling clay toward the end of the procedure. By the time the procedure is over, the PMMA is hardened to a consistency just harder than bone.

Can I melt the cement if I use a heating pad?
No, once the bone cement sets up it's that way forever.

Can I break the cement by certain activities?
No, I've never heard of anyone breaking their cement. Rarely, a patient may have another fracture at a treated level, but it's usually in severe osteoporosis and not usually related to a known cause.

Does the cement dissolve over time?
No, there is no evidence that the cement dissolves or dissipates over time.
Can the cement leak into the body?Once it sets up (by the end of the procedure) the answer is no. During the liquid state, it can leak lots of places. This is usually only an issue if a large amount leaks into the veins or by the spinal cord or nerves. Careful observation during injection is required to avoid this.

I've heard bone cement heats up; can it burn you?
When the PMMA hardens, it gives off heat. This is a common chemical phenomenon known as an exothermic reaction. If there is cement in contact with nerves, for example, it can cause irritation, however, this is very rare. Actually, the heating process has been theorized as one cause of pain relief.

That's it for now. As we get more questions we'll post them here, as well as on our FAQ at

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