Scoliosis (Idiopathic)



  • Scoliosis: lateral curvature of spine exceeding 10 degrees on PA full-spine radiograph (with rotation of spine); curves <10 are termed spinal asymmetry; considered idiopathic only after other causes have been excluded
  • Kyphosis: anteriorly concave curvature of vertebral column


  • Female-to-male ratios:
    • 1.4:1 for curves 11–20 degrees
    • 5.4:1 for curves >20 degrees


  • Generally considered 1.5–3% for curves ≥10 degrees
  • 0.3–0.5% for curves >20 degrees

Risk Factors


Positive familial history for idiopathic scoliosis in 30% (not predictive of severity)

  • Under active investigation: GWAS and whole exome sequencing studies
  • Several candidate genes have been identified.


By definition, unknown; listed are some theories, none proven in isolation:

  • Genetic
    • Positive familial history for scoliosis in 30% (not predictive of severity)
  • Connective tissue disorder
    • Associated with several connective tissue disorders (including Marfan syndrome, Ehlers-Danlos syndrome, etc.)
    • Alterations in connective tissue of the spine, paraspinous muscles, and platelets
    • May be related to osteopenia (decreased bone mineral density) of vertebral bodies
  • Neurologic (equilibrium system)
    • Abnormalities noted in vestibular, ocular, proprioceptive, and vibratory functions
  • Hormonal
    • Lower levels of melatonin secreted from pineal body in those with adolescent idiopathic scoliosis
    • Growth hormone: more of an influential factor than an etiologic factor in studies
    • Vertebral growth abnormalities
    • Asymmetric growth rates between the right and left sides of the spine

Commonly Associated Conditions

  • Connective tissue disorders, including Marfan syndrome and Ehlers-Danlos syndrome
  • Neurofibromatosis
  • Neuromuscular conditions, including cerebral palsy, spina bifida, spinal muscular atrophy, Friedreich ataxia, etc.
  • If any of these conditions are present, the diagnosis is no longer idiopathic.

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