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Idiopathic scoliosis

Last updated: February 14, 2025

Summarytoggle arrow icon

Idiopathic scoliosis is a lateral curvature of the spine with a Cobb angle ≥ 10° on x-ray with no organic underlying cause. Simultaneous rotation of the involved vertebrae also occurs. The most common classification is adolescent idiopathic scoliosis, which occurs between 10 and 12 years of age, is more common in girls, and typically manifests with a right convex thoracic curvature. Mild scoliosis is usually asymptomatic and only suspected on routine screening. The diagnosis is confirmed with spinal x-rays. Patients with red flags for scoliosis should be evaluated for nonidiopathic causes and treated as indicated. Management of idiopathic scoliosis is based on the classification, degree of curvature, and remaining growth potential. Options include regular monitoring, physical therapy, and interventions to prevent progression (i.e., with bracing and/or surgery). Progression of idiopathic scoliosis to a severe curvature may cause pain, functional impairment, and/or thoracic restriction (e.g., pulmonary disorders and heart failure).

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Epidemiologytoggle arrow icon

  • Sex: > (∼ 5:1)
  • The spinal curvature deformity can progress in skeletally immature patients as they grow.

Epidemiological data refers to the US, unless otherwise specified.

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Etiologytoggle arrow icon

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Classificationtoggle arrow icon

Classification by age

  • Infantile idiopathic scoliosis
    • Epidemiology: 0–3 years of age ( = )
    • Often manifests as a left convex thoracic curvature
    • Usually resolves spontaneously without treatment [4]
  • Juvenile idiopathic scoliosis [5][6]
    • Epidemiology: 4–9 years of age ( > ) [5]
    • Levocurvature most common in children ≤ 6 years of age; dextrocurvature most common in children > 6 years of age [5]
    • Surgery often required if the curve is ≥ 30° at the start of puberty [5]
    • Deteriorates progressively and may cause cardiopulmonary complications [5]
  • Adolescent idiopathic scoliosis (also called “late-onset scoliosis”)
  • Adult idiopathic scoliosis: the persistence or progression of childhood idiopathic scoliosis

Classification by location

  • Cervical: C2 to C6
  • Cervicothoracic: C7 to T1
  • Thoracic: T2 to T11
  • Thoracolumbar: T12 to L1
  • Lumbar: L2 to L4
  • Lumbosacral: L5 or below
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Clinical featurestoggle arrow icon

Idiopathic scoliosis is often asymptomatic and identified during well-child examinations or scoliosis screening. [2][6]

  • Abnormal posture
  • Anatomical asymmetries on visual inspection
    • Uneven shoulders, hips, waistline, and/or skin folds
    • Unilateral scapula protrusion
    • Uneven paravertebral muscles (may be the only abnormality in lumbar scoliosis)
    • Spinal curvature: a single C-shaped or compensatory S-shaped curvature [7]
  • Mild pain

Severe scoliosis may cause symptoms of respiratory distress and/or symptoms of heart failure due to thoracic restriction. [6]

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Red flagstoggle arrow icon

The following features are associated with nonidiopathic scoliosis and/or an increased risk of progression. [5][6][8][9]

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Screeningtoggle arrow icon

Some societies advocate for routine scoliosis screening. [12][13][14][15]

  • Indications
    • Once at 10 and 12 years of age in girls
    • Once between 13–14 years of age in boys
  • Modalities: visual inspection and the Adam forward bend test [13][16]
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Diagnosistoggle arrow icon

Approach [6][9]

Adam forward bend test [2][6][16]

In addition to asymmetries on visual inspection (see “Clinical features”), findings include the following:

Adolescent idiopathic scoliosis is most commonly a thoracic dextroscoliosis that manifests with a right rib hump, elevated right shoulder, and protruding right scapula. [2][6][8]

Suspect leg length discrepancy in patients with uneven iliac crests when standing and normal findings on the Adam forward bend test. [6]

Scoliosis x-ray [11]

  • Modality
  • Findings
    • Cobb angle: a radiographic measurement to assess degree of spinal curvature [16]
      • Normal: < 10°
      • Mild scoliosis: 10–24°
      • Moderate scoliosis: 25–49°
      • Severe scoliosis: ≥ 50°
    • Risser stage: a radiographic measurement of ossification of the iliac apophysis used to estimate skeletal maturity and remaining growth potential [2][8][17]

An orthopedic specialist may order a bone age to further assess skeletal maturity and remaining growth potential. [18]

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Differential diagnosestoggle arrow icon

Nonidiopathic scoliosis [5][6][9][11]

Adult degenerative scoliosis [20][21]

Adult scoliosis is typically caused by adult idiopathic scoliosis or de novo adult degenerative scoliosis. [20]

Bracing in adults may temporarily relieve pain but does not prevent curve progression and may contribute to paraspinal muscle deconditioning. [21]

The differential diagnoses listed here are not exhaustive.

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Managementtoggle arrow icon

Approach [6][8][18]

The risk for curve progression is increased in individuals with a Cobb angle of ≥ 20° if skeletally immature and > 50° if skeletally mature. [8][11][22]

Observation [6][8][18]

  • Indication: Indicated for Cobb angle 10–24°
  • Method
    • Monitor with repeat examination and/or x-rays every 6 months until the patient has no remaining growth potential. [6][8][18]
    • Refer to orthopedics (if not already done) if curvature progresses.

Interventions for scoliosis [6][8][18]

The goal of bracing and surgery is to limit or prevent the progression of scoliosis. [6][18]

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