What are the implications of a bilateral pars defect (spondylolysis)?

From the Guidelines

For a patient with a bilateral pars defect, conservative treatment with rest, physical therapy, and anti-inflammatory medications should be the initial approach, with surgical intervention considered only if symptoms persist after 6-12 months of conservative management, as recommended by recent guidelines 1. When managing a bilateral pars defect, it is essential to prioritize a conservative approach to promote healing and avoid unnecessary surgical risks. The initial treatment should include rest from aggravating activities, physical therapy focusing on core strengthening and lumbar stabilization exercises, and anti-inflammatory medications like ibuprofen (400-800mg three times daily) or naproxen (500mg twice daily) for pain relief 1.

Key Considerations

• A lumbar brace may be recommended for 6-12 weeks to limit extension movements and promote healing.
• Diagnostic imaging, including X-rays, CT scans, or MRI, may be necessary to evaluate the defect's severity if symptoms persist.
• Surgical intervention, such as direct pars repair or spinal fusion, should only be considered if conservative treatment fails after 6-12 months.
• The condition occurs most frequently in adolescent athletes participating in sports requiring repetitive lumbar extension and rotation, such as gymnastics, football, and wrestling, due to the mechanical stress placed on the developing spine during growth spurts.

Imaging Modalities

• MRI of the lumbar spine is the initial imaging modality of choice for patients with subacute or chronic low back pain who have failed conservative therapy, as it accurately depicts lumbar pathology, including disc degeneration, and the thecal sac and neural structures 1.
• CT myelography of the lumbar spine can be useful in assessing the patency of the spinal canal/thecal sac and of the subarticular recesses and neural foramen, especially in patients with implanted medical devices that are not MRI safe or conditional 1.
• Upright radiographs provide useful functional information about axial loading, and the ability to incorporate flexion and extension radiographs is essential to identify segmental motion, which is important in the surgical management of spondylolisthesis 1.

From the Research

Bilateral Pars Defect

• A bilateral pars defect is a condition where there are defects in the pars interarticularis on both sides of the spine, which can cause instability and pain in the lower back 2, 3.
• The treatment of bilateral pars defect can be challenging, and various surgical techniques have been described, including direct repair of the pars defect, posterior interbody fusion, and posterior dynamic stabilization 4, 5, 3.
• Direct repair of the pars defect is a surgical technique that involves stabilizing the defect with screws, rods, and bone grafting, without violating the facet joint or the spinal canal 2, 5.
• Posterior dynamic stabilization is a surgical technique that involves using a dynamic transpedicular stabilization system to stabilize the spine and promote fusion of the pars defect 3.
• The outcomes of surgical treatment for bilateral pars defect can be satisfactory, with significant improvement in pain and functional ability, and high rates of fusion and stabilization of the spine 2, 5, 3.

Surgical Techniques

• Direct repair of the pars defect using a rod-screw construct and bone grafting is a safe and effective technique for treating bilateral pars defect, with minimal complications and high rates of fusion 5.
• Posterior dynamic stabilization using a dynamic transpedicular stabilization system is a satisfactory technique for treating bilateral pars defect, with significant improvement in pain and functional ability, and high rates of fusion and stabilization of the spine 3.
• Pars interarticularis fusion of multiple levels of lumbar spondylolysis is a surgical technique that involves fusing the pars defects at multiple levels, using iliac bone grafting and wiring of the transverse processes and spinous processes of the involved vertebrae 6.

Patient Selection

• Patient selection is crucial for the success of surgical treatment for bilateral pars defect, and patients should be carefully selected based on their symptoms, age, and presence of degenerative disk disease or spondylolisthesis 2, 5, 3.
• Patients with bilateral pars defect who have failed conservative treatment and have significant pain and functional impairment may be candidates for surgical treatment 2, 5, 3.
• Patients with significant instability or degenerative disk disease may require alternative surgical techniques, such as posterior interbody fusion or spinal fusion 4.