Pars Fracture

About Pars Fracture

A pars fracture is a breach in the bridging bone connecting the front of the vertebra to the back spinal joints, called the facet joints. The fracture occurs in the part of the vertebrae known as the pars interarticularis. A pars fracture may also be referred to as a pars defect or spondylolysis. The defect is often asymptomatic (has no symptoms) and requires no treatment. However, in some cases, it can cause back pain severe enough to require surgery.

Common Symptoms of a Pars Fracture

Although a pars fracture can be asymptomatic, symptom can occur, leading to back pain/stiffness. Sometimes this condition leads to spinal stenosis, where the spinal canal becomes narrow and causes compression on the nerve roots.  When this happens symptoms may develop in the legs as well as the low back, leading to a condition known as neurogenic claudication. Some symptoms of this condition include:

  • Pain or tingling in the legs that increases with standing and walking
  • Leg pain or tingling that improves when bending forward or sitting
  • If severe, patients can develop leg numbness or weakness
    • The weakness often occurs with bending the foot upward, known as a foot drop

Diagnosis of a Pars Fracture

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

  • X-rays –  including X-rays taken with the patient bending forward and backward
  • MRI scan  – shows detailed image of the spinal cord and surrounding nerves
  • CT scan – shows detailed images of bones

If there is a concern that spondylosis has begun to compress nerve tissue in the spine, 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 Fracture

Nonoperative measures such as physical therapy and medication should be attempted when a patient presents with a pars fracture.  However, if back pain persists or there is compression of the nerves, surgery may be required to widen the nerve channel and restore the mechanical strength to the spine. The surgical option that is most often considered:

  • Laminectomy (removal of burn spurs or parts of the vertebra called lamina to widen the nerve channel) with a spinal fusion (locking together the involved vertebrae using metallic implants, such as screws and rods, and bone graft)