#AAOS Course: Early Onset Scoliosis-Role of Casting

By Peter Sturm MD
Courtesy : Dr Sanjay Chaturvedi, Organising Secretary, IOACON Agra

Definition

• Early onset scoliosis is defined as any spinal deformity present before the age of 10 years, irrespective of etiology.

• Earlier onset is associated with:

  • Greater curve progression

  • Worse long-term prognosis

• Children with EOS have a higher risk of developing severe spinal deformity with increased morbidity and mortality.

• Progressive deformity restricts thoracic growth and volume.

• This can result in:

  • Thoracic insufficiency syndrome

  • Cardiovascular compromise

  • Respiratory failure

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Measurement of Spinal Curvature

• Spinal curvature is measured using the Cobb angle on radiographs.

Severity Based on Cobb Angle

• Mild: less than 25°

• Moderate: 25° to 50°

• Severe: greater than 50°

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Etiological Classification of Early Onset Scoliosis

Early onset scoliosis includes the following categories:

1. Infantile idiopathic scoliosis

2. Juvenile idiopathic scoliosis

3. Congenital scoliosis

4. Neuromuscular scoliosis

5. Syndromic scoliosis

6. Scoliosis associated with tumors, infection, prior surgery, or trauma

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Infantile Idiopathic Scoliosis

• Occurs in children aged 3 years or younger.

• Accounts for approximately 4% of idiopathic scoliosis cases.

• More common in males than females.

• Typically presents with a left thoracic curve.

• Family history is often positive.

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Juvenile Idiopathic Scoliosis

• Occurs between 4 and 10 years of age.

• Accounts for approximately 15% of idiopathic scoliosis cases.

• More common in females than males.

• Most commonly presents as a right main thoracic curve.

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Congenital Scoliosis

• Results from failure of normal vertebral development during the 4th to 6th week of gestation.

• Incidence ranges from 1% to 4% in the general population.

• May occur in isolation or in association with other systemic anomalies.

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Neuromuscular Scoliosis

• Caused by disorders of the brain, spinal cord, or muscular system.

• Curves tend to:

  • Progress rapidly

  • Be long and involve multiple vertebrae

  • Occasionally involve the cervical spine

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Syndromic Scoliosis

• Occurs in association with genetic or systemic syndromes, including:

  • Marfan syndrome

  • Prader–Willi syndrome

  • Trisomy 21 (Down syndrome)

  • Ehlers–Danlos syndrome

  • Osteochondrodystrophy (dwarfism)

  • Neurofibromatosis

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Clinical Presentation

General Presentation

• Many children appear normal and function well, especially with mild curves.

• Most present due to visible deformity.

• Back pain is uncommon.

• Neurologic symptoms are usually absent.

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Physical Examination

Key Principle

• Careful assessment of body symmetry is essential for detecting scoliosis and progression.

Inspection Findings

• Uneven or tilted shoulders

• Prominence of one scapula

• Spine deviating from the midline

• Head not centered over the pelvis

• Rib prominence on one side

• Unequal hip levels

• Asymmetric waistline

• Inability to stand erect

• Leaning to one side

• Asymmetric skin creases

• Pain is uncommon but may occasionally be present

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General Examination

• Café-au-lait spots suggesting neurofibromatosis

• Cutaneous nevi

• Limb length discrepancy

• Signs of neural axis abnormalities

• Foot deformities such as cavovarus

• Gait analysis

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Spine Examination

• Midline skin abnormalities:

  • Hairy patches

  • Dimples

  • Signs suggestive of spinal dysraphism

• Rib rotational deformity or rib hump

• Adam forward bending test:

  • Demonstrates axial plane deformity in structural scoliosis

• Forward bending test in sitting position:

  • Eliminates leg length inequality as a cause

• Plagiocephaly in younger children

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Neurologic Examination

• Assessment of motor development and milestones

• Evaluation of upper and lower limbs

• Screening for cavovarus feet

• Reflex assessment:

  • Abdominal reflexes

  • Clonus

  • Hoffman sign

  • Babinski response

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Investigations

Radiographs

• Recommended views:

  • Standing posteroanterior view

  • Standing lateral view

• Evaluate for congenital vertebral anomalies.

Measurements

1. Cobb angle

2. Rib phase

3. Rib vertebral angle difference (Mehta angle)

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Magnetic Resonance Imaging

• Used to identify neural axis abnormalities.

• Mandatory in all patients with congenital scoliosis prior to surgery.

• Indicated in:

  • Curves greater than 20°

  • Presence or absence of neurologic symptoms

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Computed Tomography

• Used judiciously due to radiation exposure.

• Three-dimensional computed tomography is useful for detailed assessment of posterior bony anatomy.

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Low-Dose EOS Imaging

• Uses ultra-low radiation to generate three-dimensional models from two planar images.

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Additional Investigations

• Bone scan or dual-energy X-ray absorptiometry when indicated.

• Renal ultrasound or magnetic resonance angiography for associated renal anomalies.

• Echocardiography if cardiac involvement is suspected.

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Treatment Goals

1. Slow progression of the spinal curve.

2. Correct deformity while allowing spinal and thoracic growth.

3. Maximize pulmonary function.

4. Preserve chest wall and spinal mobility.

5. Consider overall growth and development of the child.

6. Prevent or delay definitive spinal fusion.

7. Minimize complications, procedures, hospitalizations, and family burden.

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Conservative Management Options

1. Observation and close monitoring

2. Serial casting

3. Bracing using thoracolumbosacral orthosis

4. Halo gravity traction

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Surgical Management Options

1. Non-fusion surgery

2. Definitive spinal fusion surgery

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Non-Fusion Surgery

• Indicated for curves greater than 50° in growing children.

• Allows continued spinal growth across unfused segments.

• Definitive fusion is delayed until near skeletal maturity.

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Distraction-Based Systems

• Correct deformity by applying distractive forces to the spine, ribs, or pelvis.

Examples

• Traditional growing rods

• Magnetically controlled growing rods

• Vertical expandable prosthetic titanium rib system

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Compression-Based Implants

• Modulate growth by applying compression on the convex side of the curve, inhibiting growth.

Examples

• Vertebral body stapling

• Vertebral body tethering

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Guided Growth Systems

• Use fixed and non-fixed anchors connected to rods to guide spinal growth.

Examples

• Luque trolley technique

• Shilla growth guidance technique

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Other Surgical Alternatives

1. Vertebral column resection

2. Convex hemiepiphysiodesis or convex growth arrest

3. Rib osteotomies

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Spinal Fusion Surgery

• Permanently joins 2 or more vertebrae to prevent further deformity progression.

• Limits motion at fused segments.

Types

• Anterior spinal fusion

• Posterior spinal fusion

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Prognosis

• Depends on the risk of curve progression and timing of intervention.

• Non-progressive curves may resolve spontaneously.

• Progressive curves have poorer outcomes and require treatment.

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Predictors of Progression (Mehta Criteria)

• Documented progression of Cobb angle greater than 20°

• Rib vertebral angle difference greater than 20°

• Phase 2 rib–vertebral relationship with rib overlap

• Presence of a double major curve pattern

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Crankshaft Phenomenon

• Refers to loss of three-dimensional correction after spinal surgery.

• Occurs due to continued anterior spinal growth following posterior fusion in skeletally immature patients.