Of the many causes for low back pain, one of the most common is a "slipped vertebra", or spondylolisthesis. Spondylolisthesis refers to the inability of the spine to maintain normal vertebra alignment, and a shifting forward of one vertebra on the vertebra below is the net result. Women have this condition more often than men. The most common symptoms from spondylolisthesis include low backache, aching which is worse with activity, posterior thigh pain, and occasionally radiating leg pain.

One of the most common causes of spondylolisthesis or slipped vertebra is severe arthritis in the small joints behind the vertebral body (facet joints) which allows the vertebra to shift forward in an uncontrolled fashion. This type (degenerative spondylolisthesis) of slipped vertebra is usually accompanied by nerve root compression and the clinical symptoms of back pain, buttock pain and radiating leg pain. It is usually better with sitting or lying down, and worse with standing and walking.

A second type of spondylolisthesis is present in up to 5% of the American population, and results from an old stress fracture from childhood. This type of spondylolisthesis often causes episodic low backache which is self limited and usually goes away. In some cases, hamstring spasms, radiating leg pain, and constant back pain can result. For patients with isthmic spondylolisthesis, or a slipped vertebra from a stress fracture, as the spine ages and develops arthritis, a previously asymptomatic situation can begin to hurt.

Low back pain needs to be investigated and a clear diagnosis should be made so that appropriate treatment can be started. In almost all cases, conservative care, daily exercise program, and general trunk strengthening exercises are all that is.