Neurosurgery or neurological surgery, known in common parlance as brain surgery, is the medical specialty concerned with the prevention, diagnosis, surgical treatment, and rehabilitation of disorders which affect any portion of the nervous system including the brain, spinal cord, central and peripheral nervous system, and cerebrovascular system.In different countries, there are different requirements for an individual to legally practice neurosurgery, and there are varying methods through which they must be educated. In most countries, neurosurgeon training requires a minimum period of seven years after graduating from medical school.