the article in the New England Journal of Medicine. The patient was having back surgery to fix spinal cord compression. The surgery involved injection methyl methacrylate (not polymerized) into the back, whereupon it does polymerize (with a nice little exotherm I might add). The procedure is called vertebroplasty. [*]
As is known to occasionally happen, some the the acrylate got into the bloodstream around the bone and was transported to the lungs. The plastic did interfere with the patient's breathing for a while (low O2 levels in the blood) as well as some mild increases in blood pressure. The doctors that submitted this image to the journal noted that in extreme cases, serious illness and even death can occur as a result of these types of complications.
The Wikipedia article on the procedure has quite a discussion about the effectiveness of the procedure, or more properly, the lack of effectiveness. Combine this with the risks illustrated here and I can certainly state that I would not want this done to me. I like plastics a lot, but only outside of my body, and most certainly not in my lungs.
[*] It's great to have Wikipedia back, isn't it. I missed them yesterday, but their blackout did get me to sign a petition against the SOPA/PIPA bills and contact me representatives in Congress about the issue.