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.

Physicians in this specialty treat patients suffering from numerous diseases and illnesses, but some of the most common are spondylolisthesis, spinal stenosis, spinal injury, herniated disc, brain tumors, stroke, spinal cord tumors, scoliosis, epilepsy, spinal infection, spinal discectomy, spinal deformity, brain tumor, coma, seizure, alzheimer's disease, cerebral palsy, meningitis, multiple sclerosis, and parkinson's disease.

Once properly diagnosed, practitioners can perform numerous procedures on patients including disc disease / surgery, back / spine surgery , invasive disc surgery, kyphosis surgery, laminectomy, deep brain stimulation, endoscopic surgery, craniotomy, stereotactic radiosurgery, microsurgery, endoscopic management, cordotomy, transphenoidal surgery, and radiation implants.

To diagnose patients with possible illnesses and diseases, specialists will often perform one of many tests including mri scan of the brain, mri scan of the spine, cat scan of the brain, ct scan of the brain, magnetic resonance imaging (mri), computed axial tomography (ct or cat scan), myelogram, spinal tap, lumbar puncture (lp), electromyography (emg), cerebral angiogram, electroencephalography, electronystagmography (eng), nerve conduction velocity (ncv), spinal puncture, positron emission tomography (pet scan), myelography, ocular pressures, evoked potentials studies, and myogram.

Doctor density varies by specialty and location. The United States has 6,132 practicing neurosurgeons. Broken out by state, neurosurgery doctor density in Alabama is 84, in Alaska is 7, in Arizona is 107, in Arkansas is 71, in California is 719, in Colorado is 110, in Connecticut is 83, in Delaware is 22, in District of Columbia is 50, in Florida is 371, in Georgia is 172, in Hawaii is 23, in Idaho is 27, in Illinois is 277, in Indiana is 133, in Iowa is 48, in Kansas is 45, in Kentucky is 82, in Louisiana is 110, in Maine is 28, in Maryland is 163, in Massachusetts is 194, in Michigan is 193, in Minnesota is 113, in Mississippi is 67, in Missouri is 146, in Montana is 34, in Nebraska is 45, in Nevada is 33, in New Hampshire is 30, in New Jersey is 127, in New Mexico is 31, in New York is 380, in North Carolina is 149, in North Dakota is 24, in Ohio is 266, in Oklahoma is 76, in Oregon is 135, in Pennsylvania is 320, in Rhode Island is 27, in South Carolina is 102, in South Dakota is 34, in Tennessee is 173, in Texas is 406, in Utah is 45, in Vermont is 13, in Virginia is 144, in Washington is 151, in West Virginia is 48, in Wisconsin is 168, and in Wyoming is 17.