Neurosurgery is surgery of the nervous system. A neurological surgeon, or neurosurgeon, is a specialist who is trained in surgery of the nervous system, and can perform surgery on the brain, spinal cord, or other parts of the nervous system. This specialist is sometimes called a brain surgeon. The neurosurgeon also works with patients to diagnose, evaluate, and treat diseases or disorders of the nervous system, and aids in critical care of patients before, during and after surgery.