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 7,008 practicing neurosurgeons. Broken out by state, neurosurgery doctor density in Alabama is 104, in Alaska is 10, in Arizona is 152, in Arkansas is 61, in California is 851, in Colorado is 142, in Connecticut is 89, in Delaware is 21, in District of Columbia is 59, in Florida is 412, in Georgia is 207, in Hawaii is 27, in Idaho is 35, in Illinois is 299, in Indiana is 153, in Iowa is 75, in Kansas is 57, in Kentucky is 108, in Louisiana is 110, in Maine is 28, in Maryland is 192, in Massachusetts is 246, in Michigan is 228, in Minnesota is 137, in Mississippi is 75, in Missouri is 169, in Montana is 36, in Nebraska is 55, in Nevada is 39, in New Hampshire is 34, in New Jersey is 154, in New Mexico is 39, in New York is 454, in North Carolina is 197, in North Dakota is 20, in Ohio is 336, in Oklahoma is 87, in Oregon is 113, in Pennsylvania is 336, in Rhode Island is 31, in South Carolina is 133, in South Dakota is 30, in Tennessee is 215, in Texas is 466, in Utah is 68, in Vermont is 20, in Virginia is 162, in Washington is 177, in West Virginia is 62, in Wisconsin is 150, and in Wyoming is 17.