I am assuming that part of the cranial bone was removed due to trauma or another condition and replaced with titanium. While this is an acceptable option, achieving a more symmetric head shape and better cosmetic outcome is usually possible with a custom-made implant—most commonly PEEK.I occasionally perform revision surgeries in which I remove titanium or other non-custom implants and replace them with a custom-made implant. These implants are designed specifically for your anatomy. The surgeon reviews your CT scan and performs virtual surgical planning to create the implant, and the company fabricates it exclusively for you. It cannot be used for anyone else.