Instrument to perform craniotomy.
A cranial drill, also known as a craniotome, is a tool for drilling simple burr holes (trepanation) or for creating larger openings in the skull. This exposes the brain and allows operations like craniotomy and craniectomy to be done. The drill itself can be manually or electrically driven, and primarily consists of a hand piece and a drill bit which is a sharp tool that has the form similar to Archimedes screw, this instrument must be inserted into the drill chuck to perform holes and remove materials. The trepanation tool is generally equipped with a clutch which automatically disengages once it touches a softer tissue, thus preventing tears in the dura. For larger openings, the craniotome is a surgical instrument that has replaced manually pulled saw wires in craniotomies from the 1980s.