Defined as a defect or stress fracture in the pars interarticularis of the vertebral arch.
The vast majority of cases occur in the lower lumbar vertebrae (L5), but spondylolysis may also occur in the cervical vertebrae.
The cause of spondylolysis remains unknown, however many factors are thought to contribute to its development.
The condition is present in up to 6% of the population, majority of which usually present asymptomatically.
Research supports that there are hereditary and acquired risk factors that can make one more susceptible to the defect. The disorder is generally more prevalent in males compared to females, and tends to occur earlier in males due to their involvement in more strenuous activities at a younger age.
In a young athlete, the spine is still growing which means there are many ossification centers, leaving points of weakness in the spine.
This leaves young athletes at increased risk, particularly when involved in repetitive hyperextension and rotation across the lumbar spine.
Spondylolysis is a common cause of low back pain in preadolescents and adolescent athletes, as it accounts for about 50% of all low back pain. It is believed that both repetitive trauma and an inherent genetic weakness can make an individual more susceptible to spondylolysis.