A 22-year-old woman has had the whole top of her skull replaced with a customized 3D-printed implant. The patient had been suffering from severe symptoms as a result of a condition that causes a thickening of the skull. It is believed that the procedure was the first of its kind. 3D printing has already been used in the medical field to produce lower jaw implants, prostheses and cells. In this instance, the skull was 3D-modeled and then printed as a single full piece that was able to be slotted and secured into place.