Spondylolysis (spon-dee-low-lye-sis) is a stress fracture in one of the bones (vertebrae) that make up the spinal column. It usually affects either the fourth or the fifth lumbar vertebra in the lower back and is the most common cause of low back pain in adolescent athletes.

If the stress fracture weakens the bone so much that it is unable to maintain its proper position, the vertebra can start to slip out of place. This condition is called spondylolisthesis (spon-dee-low-lis-thee-sis). In adults, spondylolisthesis is usually caused by degenerative disk disease and often affects women over 40 years of age. If too much slippage occurs, the bones may begin to press on nerves and surgery may be necessary to correct the condition.

Causes
Hereditary can play a role in developing spondylolysis. An individual may be born with thin vertebral bone and can therefore be more vulnerable to this condition. Significant periods of rapid growth may encourage slippage. Overuse, which can occur in such sports as gymnastics, weight lifting and football, can put a great deal of stress on the bones in the lower back. They also require that the athlete constantly over-stretch (hyperextend) the spine. In either case, the result is a stress fracture on one or both sides of the vertebra. Spondylolisthesis may also develop because of degenerative changes in the vertebral joints and certain medical conditions such as cerebral palsy.

Symptoms
In many people, spondylolysis and spondylolisthesis are present but do not exhibit any obvious symptoms. Pain usually spreads across the lower back, and may feel like a muscle strain. Spondylolisthesis can cause spasms that stiffen the back and tighten the hamstring muscles, resulting in changes to posture and gait. If the slippage is significant, it may begin to compress the nerves and narrow the spinal canal.

Treatment
Initial treatment for spondylolysis is always conservative. Athletes should take a break from the activities until symptoms go away, as they often do. Anti-inflammatory medications such as ibuprofen may help reduce back pain. Occasionally, a back brace and physical therapy may be recommended. Epidural steroid injections may also help alleviate inflammation and ease pain. In most cases, activities can be resumed gradually and there will be few complications or recurrence. Stretching and strengthening exercises for the back and abdominal muscles can help prevent future stress fractures. Periodic X-rays will show whether the bone is continuing to slip. Treatment is available at The Spine Center.

Surgery may be need if slippage continues, or if the back pain does not respond to conservative treatment and begins to interfere with activities of daily living. This is more often the case with degenerative spondylolisthesis.