“Sciatica” refers to symptoms related to compression of the sciatic nerve. The sciatic nerve is a collection of several nerve roots; the nerve roots come off the spinal cord in the low back. Once the nerve roots leave the spinal canal, they gather together as the sciatic nerve and travel through the buttock, down the back of the leg and into the foot. The sciatic nerve carries muscle (motor) and feeling (sensory) information to and from the central nervous system.
Symptoms or problems associated with nerve compression can include pain, numbness, tingling, and/or weakness in the region, and in rare cases problems with controlling bowels or bladder. Any of these symptoms can come on suddenly, or slowly over time.
Common causes for “sciatica” include things that cause pressure on the nerve roots within the spinal column (also known as radiculopathy) and things that cause pressure on the nerve after it has left the spine (also known as neuropathy): a slipped disk (aka herniated disk), spinal stenosis (aka narrowing), spinal instability, narrowing of muscles in the buttocks (aka piriformis syndrome), or pelvic injury.
Treatment largely includes brief bed rest (1-3 days) and medical management (spinal conditioning for most, sometime medications, sometimes physical therapy). Some will find benefit with pain management specialists. Some cases require surgery to correct the compressed area of the nerve. These procedures for decompression of nerve root(s) include laminectomy (removal of part of the bone), and/or microdiscectomy (removal of the disk) causing the compression.
Kevin White and Karin Swartz, MD
Medical Reference (2011). University of Maryland Medical Center, Baltimore MD
Oxford Medical Dictionary, 2009