Will My Cranioplasty Fracture If I Get Hit On My Head?

Q: Dr. Eppley, I’ve had a bone cement for 10 months on my forehead and this was done by my neurosurgeon. He had to elevate the depression on my forehead and on my frontal sinuses due to an accident 10 years ago. I am planning to learn mixed martial arts in a few months but I am worried that my bone cement will get hit and break. Is my bone cement as strong as the rest of my skull? Thank you very much!

A: The term ‘bone cements’ refers to a family of synthetic materials that can be used for cranioplasty purposes. Historically, this used to refer to the material PMMA or acrylic which has been used for over fifty years in cranioplasty surgery. This is still a very common material that is used by many neurosurgeons in particular. It is mixed together and creates a very strong composition similar to what most people known as plexiglass. This would resist any type of trauma much like normal skull bone would do. In the past decade new cranioplasty materials composed  of various forms of hydroxyapatite have emerged which are also known as hydroxyapatite cements (HAC) or bone cements. These are not nearly as strong and are much more brittle. These are more likely to fracture if exposed to trauma.

Your cranioplasty was an onlay or augmentative one in which whatever material was used was placed on top of existing but depressed skull bone. This is much more supportive of the cranioplasty material than if it was used to replace a full-thickness cranial defect so impact resistance is greater regardless of the material used.

If you had a PMMA cranioplasty I would have no concerns whatsoever about sustained implacts. If this was a HAC cranioplasty, however, I would be more cautious.  

Dr. Barry Eppley

Indianapolis, Indiana