An implantable shield designed to repair larger skull defects that is preformed before surgery and typically made of sheets of material (e.g., tantalum) that can be reshaped at the time of surgery without changing the physical or chemical properties of the material. The device is generally preformed with a central convex curvature matching the curvature of the forehead, side, or rear areas of the human adult skull; it is usually fixed to the intact cranial bones using screws and/or other fasteners. The device is used to repair defects due to injury, surgical intervention for tumour removal, congenital anomaly, or disease.