Spondylolisthesis is when one vertebra is unstable and slips forward on the vertebrae below. This can occur as a result of sports activity that puts stress on the bones in the lower back (such as gymnastics or football); arthritis; genetics; fracture or incidental reasons. If the vertebra slips too far, it may press on nerves and cause severe back pain or nerve crowding that produces leg pain or numbness.
Spondylolisthesis may be asymptomatic or create severe back pain, leg pain or a combination of the two.
Non-operative treatment is usually successful. Some cases may require surgery in order to restore spinal stability.