What Is Spondylolysis?
Spondylolysis is a defect that can lead to stress fractures in the posterior element of the spine 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 term is derived from the Greek words spondylos, which means spine or vertebra, and lysis, which means a break or loosening. If the stress fracture weakens the bone so much that it is unable to maintain its proper position, the vertebra can start to shift out of place, a condition called spondylolisthesis.
Spondylolysis is a common source of lower back pain in adolescents, particularly those involved in athletic activities that place a lot of stress on the lower back or cause constant overstretching (hyperextending) of the spine, such as gymnastics, weightlifting, and football. It is seen more often in males than in females. Spondylolysis is seldom seen in patients under the age of five and is found in 5% of people over the age of seven. It is a common cause of back pain in children, and the most likely cause of back pain in patients under age 26, but rarely the only cause of complaints after age 40. * The defect also may be present in adults with no prior history of injury or sports participation.
The exact cause of spondylolysis is unknown. Some theories point to genetics as a factor, suggesting that those with thinner bones are more susceptible to breakage. Others propose that repetitive trauma to the lower back weakens the pars interarticularis. Spondylolysis also may be associated with conditions that cause instability of the spine, such as lumbar disc degeneration or narrowing of the area where the nerve roots exit the spinal column (the neural foramina).