Operations on the brain, spinal cord, cranial and peripheral nerves and the membranes and fluid spaces around them. This includes craniotomy and craniectomy for tumors, hemorrhage and trauma, procedures for epilepsy and movement disorders such as deep brain stimulation, thalamotomy and corpus callosotomy, cerebrospinal fluid diversion such as shunting and ventriculostomy, nerve procedures such as rhizotomy, sympathectomy and microvascular decompression, and neurodiagnostic studies such as electroencephalography and nerve conduction study. Bony spine procedures that primarily address the vertebrae, discs and joints, such as fusion and laminectomy, are grouped instead under orthopedic surgery, since they operate on the skeleton rather than the nervous tissue itself.