Could My Cranioplasty Be Infected Or Degrading?
Q: Dr. Eppley, I had cranioplasty surgery one and a half years ago. A bone cement called acrylic was put on the area between my eyebrows(glabella) to elevate the depression on that area due to an accident. but now I noticed that there is a slight swelling on that area. This is the second time this swelling appeared. The first time was one year and three months ago and I had a cold at that time. But now I don’t have a cold but the swelling appeared again. This has never been hit by a strong force. Is this normal? Or is this a sign that the acrylic is starting to deplete and thus irritating the skin tissue covering it? But that surgery was just one and a half years ago.. too short for depletion to occur. What could be the reasons for this swelling? Thank you very much!
A: My initial reaction is no this is not normal. Since there is a synthetic material in that area that has had a few bouts of swelling, one would have to initially conclude that this does not bode well long-term for that area of reconstruction. Something is causing the area to swell up. Fortunately it does go down but I suspect this will not be the last time that it occurs.
While I don’t know the exact details of your procedure, my concern is that an acrylic material was used over an area of an old frontal sinus fracture. One of two things could be happening. First, there could be an area of residual communication between the underlying frontal sinus and the acrylic material. That could lead to intermittent low-grade infection and swelling. Secondly, a polymerized plastic like acrylic does leach out a low level of its base monomer which in a few patients may cause intermittent inflammatory reactions and tissue thinning. This would be most manifest in areas where the soft tissue cover is thinner, such as the glabellar area.
Most certainly this is not due to any degradation of the material as that does not occur. It is either frontal sinus communication or an inflammatory reaction to the material. Since it has happened only twice since surgery and always resolves, it would be something I would not immediately charge in and replace. But if it happens a third time in the near future it may give me pause to consider replacing your cranioplasty with a more biocompatible material and to check and make sure there is no communication into the frontal sinus.
Dr. Barry Eppley