Spondylolysis (pronounced spon-dee-low-ly-sis) is a defect of the spine, usually in the lower back. Specifically, it is a separation of the joint between two vertebrae that is typically caused by a stress fracture of the bone.
Spondylolysis affects 3 to 6 percent of the population and is most common in adolescents and young adults from the ages of 16 to 26.
There are several risk factors that can contribute to spondylolysis. These include:
- Age and sex: spondylolysis is more prevalent in adolescent and young adult males
- Participation in strenuous sports: repetitive lower back trauma can lead to increased stress on the lumbar spine (eg. Gymnastics, football, weightlifting, soccer)
- Genetic factors: the bony anatomy of the spine can put certain individuals at a higher risk for spondylolysis
Spondylolisthesis (pronounced spon-dee-low-lis-thesis) is a slipped or displaced vertebra relative to the one below it. It is most common in the lower back in the lumbar spine and can result in changes in posture and gait, tightness of the back and legs, pain, and sometimes tingling and numbness in the buttocks and legs. The amount displacement is measured by percentage and is graded based on severity.
- Grade 1: 0 – 25%
- Grade 2: 25 – 50 %
- Grade 3: 50 – 75%
- Grade 4: 75 – 100%
A slip greater than 100% is called a spondyloptosis when the vertebra completely displaces from the one below it.
“Isthmic” refers to a thin bony part (Isthmus) of a vertebra. This is the most common type of spondylolisthesis, which usually begins to develop between the ages of 6-16. Most occurrences of isthmic spondylolisthesis are Grade 1 or Grade 2.
This is a rare form of spondylolisthesis that is a result of a malformation of the vertebrae in the lumbar and sacral spine.
This is another rare type of spondylolisthesis that results from trauma to the lower back.
This can occur as a result of metastases or metabolic bone disease
This only occurs in older adults where the vertebrae start to degrade over time