Custom Skull Implants are Better Than PMMA Material If The Temporal Area Needs to be Covered
Q: Dr. Eppley, I’ve been saving up to have you perform a cranioplasty using custom skull implants to correct some asymmetries in my skull. When I was reading through your previous cranioplasty cases, I noticed you mentioned that typical PMMA implants could not extend past the superior temporal line. However, in one case (65 yo male), it appears that the custom implants extended over the temporal line and sat over the temporalis muscle. Is this indeed possible? Does the implant sit above or below the temporalis? If it does sit above the temporalis, could this potentially cause insult to the muscle? Is the screw secured through the muscle tissue? I was a bit disappointed to learn that a true widening of the skull could not be affectively achieved via cranioplasty, however it appears that custom skull implants can indeed broaden the skull. Would you mind clarifying these few points for me?
A: As a general rule it is not a good idea to place PMMA over onto the temporalis fascia/muscle. The firmness of the material and the sharp edges can create a palpate implant transition area and be a potential source of discomfort. A custom silicone implant is different in this regard since it is a much softer material with a finer edge and does not cause any discomfort by being on top of the fascial/muscle. It is quite common with custom skull implants to lay on top of the fascia/muscle.
Dr. Barry Eppley