surgery, a common method for treating Parkinson’s before the discovery of L-dopa, is coming back into favor for patients with severe tremors. Surgeons use various procedures to destroy tissue in regions of the brain believed to play a role in Parkinson’s disease, such as the substantia nigra. These procedures have positive effects for some people, but experts caution that they do not work for everyone. Additional surgical treatments are under investigation. Such experimental treatments include a pacemaker-like device to prevent tremors, and more recently, replacing damaged neural tissue with healthy fetal neural tissue. ...