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. California has 906 practicing neurosurgeons. Broken out by city, neurosurgery doctor density in Alameda is 1, in Anaheim is 10, in Apple Valley is 5, in Arcadia is 2, in Arcata is 2, in Bakersfield is 8, in Berkeley is 8, in Beverly Hills is 19, in Brentwood is 4, in Burbank is 4, in Burlingame is 5, in Campbell is 2, in Chico is 5, in Chino is 2, in Chula Vista is 5, in Colton is 22, in Concord is 4, in Corte Madera is 1, in Davis is 3, in Downey is 7, in Duarte is 4, in El Centro is 1, in Encinitas is 12, in Escondido is 7, in Fairfield is 2, in Folsom is 8, in Fontana is 5, in Fountain Valley is 6, in Fremont is 11, in Fresno is 25, in Glendale is 9, in Huntington Beach is 5, in Inglewood is 4, in La Habra is 1, in La Mesa is 3, in Lafayette is 1, in Laguna Hills is 5, in Laguna Niguel is 1, in Lancaster is 7, in Loma Linda is 22, in Long Beach is 16, in Los Angeles is 167, in Los Gatos is 2, in Madera is 3, in Marysville is 2, in Mission Viejo is 3, in Modesto is 8, in Montclair is 1, in Montebello is 2, in Monterey is 3, in Monterey Park is 2, in Moreno Valley is 2, in Mountain View is 9, in Murrieta is 4, in Napa is 6, in Newport Beach is 13, in Oakland is 25, in Oceanside is 7, in Orange is 22, in Oxnard is 5, in Palm Desert is 4, in Palm Springs is 10, in Palo Alto is 25, in Paradise is 1, in Pasadena is 14, in Pinole is 1, in Pleasanton is 4, in Pomona is 8, in Rancho Mirage is 7, in Redding is 9, in Redlands is 2, in Redwood City is 13, in Riverside is 14, in Sacramento is 45, in Salinas is 3, in San Bernardino is 10, in San Diego is 59, in San Francisco is 62, in San Jose is 20, in San Leandro is 3, in San Luis Obispo is 4, in San Marino is 1, in San Mateo is 2, in San Pablo is 1, in San Ramon is 6, in Santa Ana is 7, in Santa Barbara is 8, in Santa Cruz is 6, in Santa Maria is 4, in Santa Monica is 17, in Santa Rosa is 10, in Stockton is 4, in Sunnyvale is 3, in Torrance is 8, in Tustin is 3, in Visalia is 3, in Walnut Creek is 9, in West Covina is 2, in Westlake Village is 4, and in Whittier is 3.

California’s population is 36,142,137, and it is America’s third largest and most populous state. It also claims the highest and lowest altitudes in the lower 48 states. The lowest point in the country, Death Valley, is also home to the nation’s highest recorded temperature, 134 degrees. Tourists flock to this state for its many outdoor activities and attractions, including Universal Studios, Disneyland, Rodeo Drive shopping, the Golden Gate Bridge in San Francisco, wine country tours, and California’s numerous beaches and parks. Los Angeles is the nation’s second largest city, but California’s capital is Sacramento. The giant sequoias in California’s forests are among the oldest living things in the world, and a redwood in the Redwood National Park is said to be the world’s tallest tree, at 365 feet. California achieved statehood in 1850, and was named the Golden State after the beginning of the Gold Rush in 1848.

According to 2005 Census estimates, California has a population of 36,132,147. Of this population, 9,308,563 are under the age of 18 and 3,827,038 are at or above the age of 65.