Pars Defect

About Pars Defect

A Pars Defect is an abnormal break in an area of the spine called the pars interarticularis.  The pars interarticularis is the bony bridge connecting the front of the vertebra to the back parts of the spine, known as the facet joints, lamina, and spinous process. A pars defect is also called a pars fracture or spondylolysis. Some pars defects are congenital, existing at birth, but others are caused by repetitive stress and strain to the lumbar spine that can take place during adolescence.

It can cause back pain, sometimes severe enough to require surgery. Since it produces weakness in the spinal joint, it can also lead to other related degenerative spinal issues like a disc herniation, nerve compression or spondylolisthesis, which is a forward slippage of one vertebrae on another. The defect however can be asymptomatic (has no symptoms) and requires no treatment.

Common Symptoms of a Pars Defect

A pars defect can be symptomatic, with symptoms such as neck or back pain/stiffness, when symptoms do occur. Sometimes narrowing of the nerve channel, known as spinal stenosis, develops from a pars defect, and causes compression on the nerve roots.  Some symptoms related to the nerve compression include:

  • Pain radiating into the arms or legs
  • Tingling/numbness in the arms, hands, legs, and/or feet
  • Weakness in arms or legs
  • Walking difficulty
  • Coordination issues

Diagnosis of a Pars Defect

If symptoms suggest that a patient has a pars defect a doctor may order any of the following image tests:

  • X-ray
  • MRI scan  – shows detailed image of soft tissue structures, such as the spinal cord and surrounding nerves
  • CT scan – shows detailed images of bones

If there is a concern that spondylosis has begun to compress the nerves, the doctor may order a test to evaluate whether the nerve signals are traveling properly to the muscles, known as an EMG/Nerve Conduction Study.

Treatment Options for a Pars Defect

Nonoperative measures such as physical therapy and medication can  be effective when treating a pars defect. However, if pain is intractable or compression of the nerve has resulted in pain or neurological deficits, surgery may be necessary to relieve the pressure on the nerves and stabilize the spine.  Since the underlying problem is a break in the spinal bone, surgery typically will involve a stabilization and fusion.