• Clinical science

Idiopathic scoliosis


Idiopathic scoliosis is a deformity of the spine characterized by lateral deflection and rotation of the vertebral bodies. The disease typically presents in patients 10–12 years of age and is seen more commonly in girls. The most common pattern of scoliosis is a right convex curvature of the thoracic spine, resulting in forward rotation and protrusion of the right shoulder. Initially, patients do not experience any symptoms. The disease is often diagnosed incidentally or following manifestation of obvious skeletal deformities. Since scoliosis is a progressive condition, later symptoms can include pain and reduced mobility due to degenerative lesions of spinal discs and vertebrae. In severe cases of spinal deformity, patients may show signs of pulmonary restriction, including dyspnea and difficulty breathing. Scoliosis is a clinical diagnosis that is confirmed by typical findings on x-ray (e.g., Cobb angle > 10°). Treatment initially consists of observation and the use of braces. In cases of severe or rapidly progressing scoliosis, surgical treatment is necessary.



  • Sex: > (∼ 5:1)
  • Peak incidence: 10–12 years
  • The spinal curvature deformity can progress in ∼ ⅔ of skeletally immature patients as they grow.


Epidemiological data refers to the US, unless otherwise specified.




  • According to age
  • According to the pattern of the curvature: C-shaped scoliosis, S-shaped scoliosis, double S-shaped scoliosis (triple scoliosis)


Clinical features

  • Patients present because of noticeable deformities, which are especially visible on physical examination.
  • Respiratory and cardiopulmonary impairment in cases of severe thoracic deformity
  • Pain occurs secondary to degeneration, compression, or irritation of spinal discs and nerves.

The elevated part of the rib cage and the lumbar hump are always seen on the convex side of the deformity! In the most common form of scoliosis, the right convex thoracic curvature results in forward rotation and elevation of the right scapula!


Conventional x-ray

  • Indicated to evaluate necessity for treatment (see “Treatment” below”); performed in cases of deviations > 7° on scoliometer measurements
  • Evaluation of the lateral curvature (in anterior-posterior projection, full-length views)
    • Major curvature: highest deviation from the perpendicular
    • Minor curvatures: compensatory deviations from the midline above and below the major curvature
    • Cobb angle: refers to the angle between the following lines
      • 1. Perpendicular to a line drawn across the superior endplate of the highest affected vertebra
      • 2. Perpendicular to a line drawn across the inferior endplate of the lowest affected vertebra
  • Estimation of vertebral rotation (Nash and Moe method): assessment of the position of the vertebral pedicles is relation to the vertebral bodies
  • Evaluation of skeletal maturity based on lateral ossification of the apophysis across the iliac crest (Risser sign) → relevant for prognosis

Every school-aged child should undergo a physical examination of the spine in order to rule out scoliosis. Scoliosis is frequently an incidental finding!


Differential diagnoses

Secondary scoliosis

Leg-length discrepancy (short-leg syndrome)

  • Definition: A condition caused by a difference in length between each lower extremity that results in functional impairment, compensatory structural and gait abnormalities, and degenerative joint processes.
  • Etiology
  • Clinical features
    • Abnormal gait (often presents in childhood)
    • Lower back pain
    • Noticeable deformities (e.g., scoliosis)
    • Somatic dysfunction
    • Progressive joint degeneration
  • Physical examination
    • Abnormalities in gait
    • Rotated pelvis
    • Unleveling of the sacrum
    • Lateral thoracic and lumbar curvatures
  • Diagnostics
  • Treatment
    • Nonsurgical approach
      • Observation: if a child has not reached skeletal maturity
      • Shoe-lifts
    • Surgical approach
      • Epiphysiodesis
      • Limb lengthening or shortening procedures


The differential diagnoses listed here are not exhaustive.


  • Treatment based on the Cobb angle
    • Cobb angle < 10°: per definition not scoliosis, and therefore not monitored
    • Cobb angle 10–19°: continual monitoring for progression
    • Cobb angle 20–29°: monitoring or bracing
    • Cobb angle 30–39°: bracing
    • Cobb angle > 40° or rapidly progressing scoliosis: surgery
  • Bracing
    • 18 hours/day, if possible
    • Bracing is usually able to halt progression, but cannot cure the underlying condition.
  • Surgery
    • Goal: correct spinal arching and rotation
    • Various surgical techniques and approaches exist (ventral, lateral, dorsal, or combined approach).
    • Spondylodesis: fusion of the vertebrae by bridge plating or by internal fixation
    • Risks: paraplegia (< 1% of cases), development of pseudarthroses, infection of surgical material