Custom skull implants are the most effective method for aesthetic skull augmentations of all types. Their large surface areas of coverage provide for augmentation effects that blend in well with the surrounding bone for more natural head shape effects.
But what also makes custom solid silicone skull implants so appealing is that they can be inserted through relatively small scalp incisions. (a coronal scalp incision is never needed) This is possible because the solid material has flexibility. (not completely rigid) Such flexibility should not be confused with being a soft implant…as it is not. It is firm but flexible. This allows skull implants to be placed through scalp incisions smaller than one could imagine that can heal remarkably well with near imperceptibility.
But this flexibility is affected by the thickness of the material. The thicker the implant is the less flexible it becomes. As a result small scalp incisions may require an additional technique for the skull implant to be inserted. If the implant can not bend/fold enough to become smaller, it can be split into two pieces which can be inserted separately. Rather than a straight line split, a geometric split is better.
When making an implant split it has to be considered how it will be re-assembled once inside the patient under the scalp. How can it reliably be put back together when much of the implant can not be seen from the outside? A straight line split could easily shift between the two implant sides. Any discrepancy at the front and back of the implant will surely be seen later as a visible edge or step off. This is where the geometric split has enormous value. It allows the implant to come back together as it as before it was split, very similar to two puzzle pieces. There is only one way it can fit. Any non-fitting of the two implant halfs becomes very evident.
Dr. Barry Eppley