Spondylolisthesis is a condition in which a bone (vertebra) in the lower part of the spine slips out of the proper position onto the bone below it.
Causes, incidence, and risk factors
In children, spondylolisthesis usually occurs between the fifth bone in the lower back (lumbar vertebra) and the first bone in the sacrum (pelvis) area. It is often due to a birth defect in that area of the spine or sudden injury (acute trauma).
In adults, the most common cause is degenerative disease (such as arthritis). The slip usually occurs between the fourth and fifth lumbar vertebrae.
Other causes of spondylolisthesis include bone diseases, traumatic fractures, and stress fractures (commonly seen in gymnasts). Certain sport activities -- such as gymnastics, weight lifting, and football -- put a great deal of stress on the bones in the lower back. They also require that the athlete constantly overstretch (hyperextend) the spine. This can lead to a stress fracture on one or both sides of the vertebra. A stress fracture can cause a spinal bone to become weak and shift out of place.
Spondylolisthesis may vary from mild to severe. A person with spondylolisthesis may have no symptoms.
The condition can produce increased lordosis (also called swayback), but in later stages may result in kyphosis (roundback) as the upper spine falls off the lower spine.
Symptoms may include:
Lower back pain
Muscle tightness (tight hamstring muscle)
Pain in the thighs and buttocks
Tenderness in the area of the slipped disc
Nerve damage (leg weakness or changes in sensation) may result from pressure on nerve roots and may cause pain radiating down the legs.
Signs and tests
The doctor will perform a physical exam. A straight leg raise may be uncomfortable or painful.
X-ray of the spine can show if a vertebra is out of place, and whether there are any fractures.
Treatment varies depending on the severity of the condition. Most patients get better with strengthening and stretching exercises combined with activity modification, which involves avoiding hyperextension of the back and contact sports.
Nonsurgical treatments are tried first. This may include:
Anti-inflammatory medicines to reduce back pain
A stiff back brace
You should take a break from activities until your symptoms go away. In most cases, you can resume activities slowly.
Surgery to fuse the slipped disc may be needed if you have severe pain that does not get better with treatment, a severe slip of the vertebra, or any neurological changes. Such surgery has a higher rate of nerve injury than most other spinal fusion surgeries. A brace or body cast may be used after surgery.
Periodic x-rays can show whether the vertebra is changing position over time.
Conservative therapy for mild spondylolisthesis is successful in about 80% of cases.
When necessary, surgery leads to satisfactory results in 85 - 90% of people with severe, painful spondylolisthesis.
If too much slippage occurs, the bones may begin to press on nerves. Surgery may be necessary to correct the condition.
Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine; C. Benjamin Ma, MD, Assistant Professor, Chief, Sports Medicine and Shoulder Service, UCSF Department of Orthopaedic Surgery. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.