This term refers to pain radiating into an extremity (arm or leg) that is caused by compression or irritation of a spinal nerve. This can occur from acute compression as with a disc herniation or it can occur more chronically from the slow overgrowth of bone. Chronic radiculopathy occurs when the pain is longstanding and not responsive to basic treatments; it can follow open surgery when scar tissue develops and chronically irritates the encased nerve.