Surgery
(from the Greek: χειρουργική cheirourgikē (composed of χείρ, “hand”, and ἔργον, “work”), via Latin: chirurgiae, meaning “hand work”) is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.
See neurosurgery.
Emergency surgery is one that must be performed without delay; the patient has no choice other than immediate surgery, if they do not want to risk permanent disability or death.