<unk>  is a surgical operation on the repairing of cranial defects caused by previous injuries or operations, such as decompressive craniectomy. It is performed by filling the defective area with a range of materials, usually a bone piece from the patient or a synthetic material.<unk>  is carried out by incision and reflection of the scalp after applying anaesthetics and antibiotics to the patient. The temporalis muscle is reflected, and all surrounding soft tissues are removed, thus completely exposing the cranial defect. The<unk>  flap is placed and secured on the cranial defect. The wound is then sealed.<unk>  was closely related to trephination and the earliest operation is dated to 3000 BC. Currently, the procedure is performed for both cosmetic and functional purposes.<unk>  can restore the normal shape of the skull and prevent other complications caused by a sunken scalp, such as the "syndrome of the trephined".<unk>  is a risky operation, with potential risks such as bacterial infection and bone flap resorption.
Cranioplasty
Astragalectomy
Craniotomy
Cerebrospinal fluid diversion
Decompressive craniectomy
Minimal-access cranial suspension
Head transplant
Lumbar–peritoneal shunt