Pediatric Spondylolysis and Spondylolisthesis

Epidemiology

• Common in adolescents

• Higher incidence in:

  • Athletes (gymnastics, football, wrestling)

• Often develops during growth

Etiology / Pathophysiology

• Repetitive lumbar extension and rotation

• Stress injury → pars fracture

• Bilateral defects → instability → slip

Classification

Wiltse Classification

1. Type I: Dysplastic (Congenital) – Malformation of the L5 arch or upper sacrum.

2. Type II: Isthmic – Pars interarticularis defect (Most common in pediatrics).

3. Type III: Degenerative – (Common in adults, rare in pediatrics).

Meyerding Grading (Slip Severity)

• Grade I: <25%

• Grade II: 25–50%

• Grade III: 50–75%

• Grade IV: 75–100%

• Grade V: >100% (spondyloptosis)

Clinical Presentation

• Low back pain (activity-related)

• Pain worsens with:

  • Extension

  • Sports

• Tight hamstrings

• Radiculopathy (in higher-grade slips)

Physical Examination

• Lumbar hyperextension pain

• Hamstring tightness

• Step-off deformity (advanced cases)

• Phalen-Dickson Sign: "Crouched" gait with flexed hips and knees due to severe hamstring tightness.

• Step-off deformity: Palpable shelf in the spinous process (High-grade).

Imaging

X-ray

• Lateral view → slip grading

• Oblique view → pars defect (“Scotty dog sign”)

MRI

• Early stress reaction (before fracture visible)

• Nerve compression

CT

• Best for confirming pars defect

Natural History

• Many cases remain stable

• Progression risk higher in:

  • Younger patients

  • High-grade slips

Treatment

Nonoperative (First-line)

Indications

• Spondylolysis

• Low-grade spondylolisthesis (Grade I–II)

Management

• Activity modification

• Physical therapy (core strengthening)

• Bracing (selected cases)

Goal:

• Pain control

• Healing of pars (if early)

Operative Treatment

Indications:

• Persistent pain despite 6 months of conservative treatment.

• Neurologic deficit.

• Progressive slip (> Grade II).

• High-grade slip at initial presentation.

Options:

• Pars Repair: Direct repair of the defect (Snyder or Buck technique) in young patients with no slip.

• Posterolateral Fusion (In-situ): Most common for Grade I-II.

• Interbody Fusion (ALIF/TLIF/PLIF): Often required for high-grade slips to improve fusion rates and restore alignment.

Complications

• Progression of slip

• Chronic pain

• Nonunion (pars)

• Neurological symptoms

Prognosis

• Excellent in most cases with conservative treatment

• Surgical outcomes generally good when indicated

Pits and Pearls

• Pars stress reaction is early stage → MRI sensitive

• Most pediatric cases are isthmic type

• Low-grade slips → conservative first

• High-grade slips → higher progression risk

Pitfalls

• Missing early stress fracture (normal X-ray)

• Over-imaging with CT (radiation)

• Ignoring hamstring tightness

• Delaying surgery in progressive high-grade slips

Mini Decision Algorithm

Concept Summary

• Stress → Pars defect → Possible slip

• Early diagnosis prevents progression