When is pars repair indicated for pediatric patients with spondylosis or spondylolisthesis?

Indications for Pars Repair in Pediatric Spondylolysis or Spondylolisthesis

Pars repair is primarily indicated for symptomatic pediatric patients with spondylolysis or low-grade spondylolisthesis (≤50% slip) who have failed conservative management, particularly when the defect is located above L5 or involves multiple levels. 1

Diagnostic Approach

Before considering surgical intervention, proper diagnosis is essential:

1. Initial Imaging:

   • Radiographs of the spine are the first-line screening tool (sensitivity of 77.6% for AP and lateral views) 2
   • MRI without contrast is recommended for persistent symptoms to detect active spondylolysis, showing edema in the pars interarticularis 2
   • CT provides high sensitivity for evaluating bony defects in spondylolysis 2
   • Bone scan with SPECT may be useful for detecting active spondylolysis when MRI is contraindicated 2

2. Clinical Presentation:

   • Activity-related low back pain
   • Painful spinal mobility
   • Hamstring tightness
   • Absence of radiculopathy in most cases 3

Treatment Algorithm

Conservative Management (First-Line)

Most pediatric cases should initially undergo conservative treatment:

• Activity restriction
• Thoracolumbosacral orthotic bracing
• Physical therapy focusing on core strengthening and hamstring/hip flexor stretching 4
• Duration: Typically 3-6 months 3

Surgical Indications for Pars Repair

Pars repair should be considered when:

1. Failure of Conservative Treatment:

   • Persistent symptoms despite 6+ months of appropriate conservative management 5
   • Refractory pain that limits activities of daily living 4

2. Anatomical Considerations:

   • Spondylolysis or low-grade spondylolisthesis (≤50% slip) 1
   • Pars defects located cephalad to L5 (above L5) 1
   • Multiple-level pars defects 1
   • Mobile spondylolisthesis that hasn't progressed to high-grade 1

3. Patient Factors:

   • Physically active adolescents with significant functional limitations 6
   • Absence of significant disc degeneration at the affected level 6
   • Younger patients with greater potential for healing 3

Contraindications for Pars Repair

Pars repair is not recommended for:

• High-grade spondylolisthesis (>50% slip) - these cases require fusion 1
• L5 pars defects with spondylolisthesis (in situ posterolateral L5-S1 fusion is preferred) 1
• Dysplastic spondylolisthesis at the lumbosacral junction 1
• Significant disc degeneration at the affected level

Surgical Techniques

When pars repair is indicated, options include:

• Screw repair of the pars defect
• Wiring transverse process to spinous process
• Pedicle screw-laminar hook fixation 1

Benefits of Pars Repair vs. Fusion

The primary advantage of direct pars repair over fusion is:

• Preservation of spinal segment mobility 6
• Maintenance of anatomical integrity 6
• Faster return to activities 6
• Avoidance of adjacent segment degeneration

Outcomes and Prognosis

Direct pars repair has demonstrated:

• High rates of bony union (radiographic fusion) 6
• Return to full activity in most patients 6
• Low complication rates 6
• Minimal hospital stays (average 3.2 days) 6

Common Pitfalls to Avoid

1. Misdiagnosis: Ensure proper imaging to differentiate between active and chronic spondylolysis
2. Premature surgery: Ensure adequate trial of conservative management (minimum 6 months)
3. Improper technique selection: Pars repair is not appropriate for high-grade slips or L5 pars defects with spondylolisthesis
4. Overlooking disc degeneration: Significant disc degeneration may necessitate fusion rather than pars repair

In summary, pars repair offers an effective surgical option for carefully selected pediatric patients with spondylolysis or low-grade spondylolisthesis, preserving motion and anatomical integrity while providing pain relief and return to function.