Can My Small PMMA Bone Cement Occipital Augmentation Be Replaced With A Larger Custom Skull Implant?

Q: Dr. Eppley, I had PMMA bone cement augmentation to the back of my head done in South Korea several years ago. Its effect was very limited and I now wish to replace it with a custom skull implant. I was told at the timeI was told at the time that my result was limited because my scalp was too tight to accommodate much of the bone cement. One question I have is whether the PMMA bone cement will need to be removed and replaced or whether a skull  implant can be designed to fit over it. If I get a custom skull implant will I be able to participate in sports and other physical activities? Lastly how durable are custom skull implants long-term?

A:1 )The limitation with PMMA bone cement skull augmentation is not scalp stretch. It is the material itself. When you place a putty like material under the tight scalp the scalp pushes back as the material sets. This produces a limited augmentation effect as the bone cement is flattened. This is only a avoided if one has a full coronal scalp incision where the bone cement is placed in an open setting without the pressure of the scalp on it where its shape and volume can be better controlled. This is where implants have a huge advantage over bone cements but only because of their preform shade but also because they push out the scalp more effectively and resist any rebound scalp pressure. The difference in the volumes obtained between the two methods of skull augmentation are usually 3 to 1 with implants being able to create 3 to 4 times the volume that bone cement can.

2) Whether in considering secondary custom skull implant augmentation the PMMA bone cement is removed or the implant overlaid on the existing cement depends on several factors which can only be better assessed with the 3-D CT scan.  I have done it numerous times both ways. But should the cement need to be removed it is done at the same time as the implant placement. The Implant is designed by digitally removing the cement seen on the scan.

3) In my extensive skull implant experience patients are able to go on with life and fully participate in any activities that they so desire.

4) Skull implants are just as durable as bone cement. Both materials are structurally stable and are unable to be broken down by the body.

Dr. Barry Eppley

Plastic Surgeon