What is spondylolysis?

Spondylolysis is a specific defect in the connection between vertebrae (the bones that make up the spinal column). This defect can lead to small stress fractures (breaks) in the vertebrae that can weaken the bones so much that one slips out of place, a condition called spondylolisthesis. Spondylolysis is a very common cause of low back pain.

The word spondylolysis comes from the Greek words spondylos, which means spine or vertebra, and lysis, which means a break or loosening.

How common is spondylolysis?

Spondylolysis affects about 3% to 7% of Americans. The condition is a common cause of low back pain in children and the most likely cause of low back pain in people younger than 26 years of age. Spondylolysis is more common in children and teens participating in sports that place a lot of stress on the lower back or cause a constant over-stretching (hyperextending) of the spine, such as gymnastics, weightlifting, and football. It is seen more often in males than in females.

What causes spondylolysis?

Spondylolysis results from a weakness in a section of the vertebra called the pars interarticularis, the thin piece of bone that connects the upper and lower segments of the facet joints. Facet joints link the vertebrae directly above and below to form a working unit that permits movement of the spine.

The exact cause of the weakness of the pars interarticularis is unknown. One theory points to genetics (heredity) as a factor, suggesting that some people are born with thin vertebrae, which places them at higher risk for fractures. Another theory suggests that repetitive trauma to the lower back can weaken the pars interarticularis.

What are the symptoms of spondylolysis?

Many people with spondylolysis have no symptoms and don't even know they have the condition. When symptoms do occur, low back pain is the most common. The pain usually spreads across the lower back, and might feel like a muscle strain. The pain is generally worse with vigorous exercise or activity. Symptoms often appear during the teen-age growth spurt. The typical age of a person diagnosed with spondylolysis is 15 to 16 years.

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