Spondylolysis / Spondylolisthesis

Spondylolysis is the name given to a specific stress fracture in the spine.

Spondylolisthesis is the name used when, because of the stress fracture (spondylolysis), there is a forward slip of one vertebra on the one below.

  • The stress fracture occurs in around 5% of the population.
  • 25% of these develop the forward slippage (spondylolisthesis).
  • The forward slippage doesn’t normally increase over time; ie it is usually stable.
  • It is not necessarily painful. This means that not everyone with spondylolysis or spondylolisthesis has pain.
  • Most commonly it develops during the teenage years.
  • It is 2-3 times more common in young athletes compared to the general population.
  • It is more often seen in athletes who are involved in gymnastics, weight lifting, wrestling, diving, and cricket bowlers (especially fast bowlers).

Why Does It Happen?

  1. Adaptive:
    In most cases these changes are “adaptive”. This means that the stress fracture develops because of the activities the person is involved with. It is a gradual process, where a load is passed through the spine repeatedly over time. The spine attempts to modify its structure, or adapt, in order to cope with these loads more efficiently. The load that cause these stress fractures to form usually involves extending (arching) the spine. One of the effects of the formation of the spondylolisthesis is to allow more movement when extending the lower back. They are more common in those involved in sports like gymnastics or fast bowlers in cricket as these sports demand more movement into extension.

  2. Congenital
    There are sometimes inherited variations in the structure of the spine that leave a person more likely to develop this stress fracture.

  3. Degenerative
    The normal wear process of the spine can sometimes lead to the slippage (spondylolisthesis) of one vertebra on another. This is because the wear process of the spine allows increases in shear stresses (greater movement forward and backward of the vertebra on one another). This can weaken the restraining joint resulting in the slip.

How Are They Diagnosed?

There are several radiological studies that can be done to confirm the diagnosis. The easiest is a XRay taken at an oblique angle. This will pick up many of these stress fractures. A bone scan (scintigram) is sometimes used and highlights inflammation at the sight of the stress fracture. The presence of inflammation suggests the stress fracture is causing pain. The most accurate image of the stress fracture is carried out using a CT scan.

Treatment

  1. Conservative (non-surgical):
    Most of these problems can be well managed with a programme of exercises that are specific to each individual’s problem. These exercises will aim to unload the stress fracture and thereby relieve pain. Specific strengthening exercises then help to support the area and potentially reduce the risk of the pain returning.

  2. Surgical:
    Sometimes it is necessary to stabilise the area via surgery. This is only performed where it is unlikely conservative treatment will be successful and the symptoms are causing significant problems in normal daily activities.