These are separate but sometimes related conditions.
Spondylolysis is a spinal fracture of a bone structure called the pars interarticularis, which connects the facet joints of the spine. The spinal cord is protected by rings of bone that make up the middle and posterior (rear) portion of the spinal column. In each of these rings, the pars interarticularis (or simply "pars" for short) connects other components of the ring, known as the pedicle and lamina. (See figure 1.)
Spondylolysis (sometimes called by the shortened name, "pars fracture") usually occurs during childhood or adolescence from repetitive stress, rather than from an acute injury. In other words, it is usually a stress fracture rather than a sudden break. This is a common condition of children and teenagers who are involved in organized sports. Active kids and teens with spondylolysis may experience symptoms. However, some people with this condition may not develop symptoms until later in adulthood.
Illustration of the Spinal Column and Location of a Pars Fracture (Spondylolysis)
The lower portion of the spinal column is called the lumbar spine. Spondylolysis most commonly occurs in the lower back in the lowest lumbar vertebra (L5). In athletes, this type of injury can be seen when the back is bent backwards repeatedly, in activities such as gymnastics, karate and football. Specifically, this is common in offensive and defensive linemen.
The vertebra initially responds to increased physical strain of such activity by gradually adding new bone cells around the stressed area of the spine. However, an injury can occur too quickly for the vertebra to be repaired, and this leads to a crack in the pars. The crack may affect only one side, but it is not uncommon to have fractures on both sides of the vertebra. When fractures occur on both sides, it is possible for one vertebra to translate or move forward or backward over the neighboring vertebra; this is called spondylolisthesis.
Those with a pars fracture may feel pain and stiffness in the lower back that is worsened with activity and improves with rest. Hyperextension (abnormal stretching) of the lower back will usually aggravate the area as it overloads the pars fracture.
Occasionally, nerve symptoms can be present that may include a “pins and needles” sensation in a leg, with or without numbness or weakness in the leg.
Evaluation for this condition would include a review of the patient’s medical history and a physical exam, followed by X-rays, which can detect pars fractures.
A bone scan can be used for early detection of a stress fracture of the pars. This involves injecting chemical "tracers" into the blood stream. The tracers then show up on special spine X-rays. The tracers collect in areas of increased metabolism or cell activity in bone tissue, such as would be seen in areas of a stress fracture of the pars interarticularis.
The treatment for a pars fracture is initially nonsurgical and includes rest and bracing. The fracture can be assessed with a series of X-rays every few months.
Bracing can last for 3 to 4 months while the fracture heals, and physical therapy can also be included to maintain and help strengthen the abdominal and back muscles with specific directed exercises.
If the athlete has persistent pain after nonsurgical treatment, surgery may be required. There are two operations that may be performed:
Spondylolisthesis is when spinal vertebrae slip forward over one another. This is often caused when the crack in a pars fracture affects both sides of connection between the lamina and pedicles). In this way, the condition can be a direct result of spondylolysis. However, there is another form of this condition, called degenerative spondylolisthesis. This condition is caused by the deterioration (degeneration) of the facet joints and discs of the spine.
Symptoms can include:
Below, find articles and other content for more information about these conditions, as well as a link to HSS doctors who treat them.