Summary

• Infantile Idiopathic Scoliosis is a coronal plane spinal deformity which most commonly presents in children ages 3 years or less.

• Diagnosis is made with full-length PA and lateral spine radiographs. MRI studies are indicated to rule out syrinx, tumor, or tethered cord. 

• Treatment can be observation, bracing, or surgical management depending on the skeletal maturity of the patient, magnitude of deformity, and curve progression.

Epidemiology

• Incidence

  • 4% of idiopathic scoliosis cases

• Demographics

  • males > females

• Anatomic location

  • usually left thoracic

• Risk factors

  • family history

Etiology

• Pathophysiology

  • pathoanatomy

    • may adversely affect growth of alveoli and normal development of the thoracic cage

• Genetics

  • autosomal dominant with variable penetrance

• Associated conditions

  • plagiocephaly (skull flattening) 

  • congenital defects

  • neural axis abnormalities

    • 22% of patients with curves > 20° will be affected

      • 80% of these patients will need neurosurgical involvement

  • thoracic insufficiency syndrome

    • characterized by decreased thoracic growth and lung volume

    • leads to pulmonary hypertension and cor pulmonale

    • pulmonary function impairment associated with curves > 60°

    • cardiopulmonary issues associated with curves > 90°

Anatomy

• Osteology

  • the T1-L5 spinal segment grows fastest in the 1st five years of life

    • the height of the thoracic spine increases by 2 times between birth and skeletal maturity

Classification

• Infantile Idiopathic Scoliosis consists of

  • resolving type

  • progressive type

• Early onst scoliosis

  • early-onset scoliosis is a broader category that includes scoliosis in children < 10 years. It includes

    • infantile idiopathic scoliosis (this topic)

    • juvenile idiopathic scoliosis 

    • congenital scoliosis 

    • neurogenic scoliosis 

    • syndromic scoliosis

      • Marfan's 

      • Down's syndrome 

Presentation

• History

  • age deformity was first noticed and any observed progression

  • perinatal history

  • developmental milestones

• Presentation

  • most present with deformity

  • excessive drooling may reflect neurologic condition

• Physical exam

  • inspection

    • cafe-au-lait spots (neurofibromatosis) 

    • patches of hair

    • dimpling over the spinal region

      • dimpling outside of the gluteal fold is usually benign

    • nevi or other tumors may be indicative of spinal dysraphism

    • plagiocephaly (skull flattening)

  • neurologic

    • motor

      • document developmental milestones

      • evaluate for cavovarus feet

    • upper and lower extremities exam

    • reflexes

      • abnormal abdominal reflexes

        • associated with the presence of a syrinx

      • clonus

      • Hoffman sign

      • Babinski

  • gait analysis

Imaging

• Radiographs

  • recommended views

    • standing PA and lateral

      • supine in infants unable to stand (will make curve appear less severe)

  • findings

    • look for congenital vertebral defects

  • measurements

    • cobb angle

      • > 20 degrees associated with progression

    • rib phase 

      • technique

        • convex rib head position with respect to the apical vertebrae

      • findings

        • phase 1 - no rib overlap

        • phase 2 - rib overlap with the apical vertebrae

          • high risk for curve progression

    • RVAD (rib vertebrae angle difference, Mehta angle) 

       

      • technique 

        • measure angle between the endplate and rib (line between midpoint of rib head and neck)

        • RVAD = difference of 2 rib-vertebral angles

      • findings 

        • > 20° is linked to high rate of progression

        • < 20° is associated with spontaneous recovery

• MRI

  • obtain MRI of spine first to rule out

    • tether

    • cyst

    • tumor

    • syrinx (20% incidence)

Treatment

• Nonoperative

  • observation alone (most resolve spontaneously)

    • indications

      • Cobb angle < 30°

      • RVAD < 20°

    • 90% will resolve spontaneously

  • serial Mehta casting (derotational) or thoracolumbosacral orthosis (TLSO) 

      

    • indications

      • flexible curves

      • Cobb angle > 30°

      • RVAD > 20°

      • phase 2 rib-vertebrae relationship (rib-vertebral overlap)

    • mechanism

      • functions to straighten the spine in young patients

      • in older patients it serves as an adjunctive measure prior to definitive treatment

  • bracing

    • indications

      • incompletely corrected curves after Mehta casting

      • late presenting cases where the spine is still flexible

• Operative

  • growing rod construct (dual rod or VEPTR)

    • indications

      • Cobb > 50 to 60 degrees

      • failed Mehta casting or bracing

    • fusion

      • delay until as close to skeletal maturity as possible

      • fusion before age 10 years results in pulmonary compromise

    • outcomes

      • improvement in FVC pulmonary function with implementation of growing construct 

Tecgniques

• Growing rod construct (dual rod or VEPTR)

  • permits growth of affected part of spine up to 5 cm

  • dual rods or VEPTR

    • use anchors proximally and distally

    • serial lengthening

      • required every six to eight months

Complications

• High rate of complications with surgical treatment

Prognosis

• Progression

  • most resolve spontaneously

  • if progressive by age 5, >50% of children will have a curve > 70°

• Mehta predictors of progression

  • Cobb angle > 20°

  • RVAD > 20°

  • phase 2 rib-vertebral relationship (rib-vertebral overlap)

• Prognosis

  • progressive curves have poor outcomes and must be treated

  • can be fatal if not treated appropriately