orNeurosurgery, or neurological 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, peripheral nerves, and extra-cranial cerebrovascular system. Neurosurgery, or neurological 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, peripheral nerves, and extra-cranial 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. In the United States, a neurosurgeon must generally complete four years of undergraduate education, four years of medical school, and seven years of residency (PGY-1-7). Most, but not all, residency programs have some component of basic science or clinical research. Neurosurgeons may pursue additional training in the form of a fellowship, after residency or in some cases, as a senior resident. These fellowships include pediatric neurosurgery, trauma/neurocritical care, functional and stereotactic surgery, surgical neuro-oncology, radiosurgery, neurovascular surgery, skull-base surgery, peripheral nerve and spine surgery. In the U.S., neurosurgery is considered a highly competitive specialty composed of 0.5% of all practicing physicians. In the United Kingdom, students must gain entry into medical school. MBBS qualification (Bachelor of Medicine, Bachelor of Surgery) takes four to six years depending on the student's route. The newly qualified physician must then complete foundation training lasting two years; this is a paid training program in a hospital or clinical setting covering a range of medical specialties including surgery. Junior doctors then apply to enter the neurosurgical pathway. Unlike most other surgical specialties, it currently has its own independent training pathway which takes around eight years (ST1-8); before being able to sit for consultant exams with sufficient amounts of experience and practice behind them. Neurosurgery remains consistently amongst the most competitive medical specialties in which to obtain entry. Neurosurgery, or the premeditated incision into the head for pain relief, has been around for thousands of years, but notable advancements in neurosurgery have only come within the last hundred years. The Incas appear to have practiced a procedure known as trepanation since the late Stone age. During the Middle Ages in Al-Andalus from 936 to 1013 AD, Al-Zahrawi performed surgical treatments of head injuries, skull fractures, spinal injuries, hydrocephalus, subdural effusions and headache. There was not much advancement in neurosurgery until late 19th early 20th century, when electrodes were placed on the brain and superficial tumors were removed. History of electrodes in the brain: In 1878 Richard Canton discovered that electrical signals transmitted through an animal's brain. In 1950 Dr. Jose Delgado invented the first electrode that was implanted in an animal's brain, using it to make it run and change direction. In 1972 the cochlear implant, a neurological prosthetic that allowed deaf people to hear was marketed for commercial use. In 1998 researcher Philip Kennedy implanted the first Brain Computer Interface (BCI) into a human subject. History of tumor removal: In 1879 after locating it via neurological signs alone, Scottish surgeon William Macewen (1848-1924) performed the first successful brain tumor removal. On November 25, 1884 after English physician Alexander Hughes Bennett (1848-1901) used Macewen's technique to locate it, English surgeon Rickman Godlee (1849-1925) performed the first primary brain tumor removal, which differs from Macewen's operation in that Bennett operated on the exposed brain, whereas Macewen operated outside of the 'brain proper' via trepanation. On March 16, 1907 Austrian surgeon Hermann Schloffer became the first to successfully remove a pituitary tumor.