Pars defect (Spondylolysis)

Specialty of Sports medicine

The pars defect is a condition affecting the part of the vertebra in the lumbar spine (lower back), called the pars interarticularis, which is a small section of bone that joins the facet joints in the spine.

What are the symptoms of pars defect?

The main symptom of pars defect is lower back pain. The pain often radiates into the buttocks and legs can restrict daily activity. The defect doesn’t always show symptoms, especially in young adults, but repeated exercise can cause the onset of the pain symptoms. The pain usually presents as a sharp pain at first, though it can develop gradually, and may come and go, especially when at rest. Lower back pain lasting longer than two weeks should always be investigated further by a specialist.

What are the causes of pars defect?

The cause of the pars defect is a stress fracture from excessive pressure on the spine, in particular on the pars interarticularis, causing this weak spot to break. Due to the cause, this condition is particularly prevalent in people partaking in regular sports, especially athletics, weight lifting, wrestling, gymnastics, and many other popular sporting activities. It often occurs during hyperextension or bending backwards. The condition sometimes only develops on one side of the spine, but can also both sides which means the vertebrae becomes broken into two parts.

Treatment for pars defect

Treatment of the pars defect is usually that of immobilisation of the area of the stress fracture, and rest. The fracture will need to be immobilised in position near the spine, and mechanical support may be used to immobilise the lower spine during the healing process. Once the fracture has healed, the patient will be required to carry out physical therapy activities to strengthen the area. Electrical stimulation, ultrasound, massages and hydrotherapy may also be used to help speed up the recovery.

Prevention of pars defect

Advancements in imaging technology can now allow specialists to identify stress injuries in the pars interarticularis before they develop into fractures.


If a stress injury is detected, braces may be used to restrict movement in the area of the spine, to allow the stress fracture to heal before it develops into a more serious fracture.

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