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Introduction and definition
Scoliosis is a persistent, usually lateral, deviation of the spine accompanied by vertebral rotation and loss of the normal coronal and sagittal alignment. It is diagnosed radiologically when the major curve measures at least 10° by the Cobb method on a standing radiograph. Curves below 10° are generally termed spinal asymmetry rather than scoliosis. The deformity is three-dimensional: the coronal curvature is associated with axial rotation, rib prominence and, in some patients, thoracic hypokyphosis or sagittal imbalance.
Classification of scoliosis
1. Classification according to aetiology
| Group | Subtypes and defining features | Clinical significance |
|---|---|---|
| Non-structural or functional | Postural curve, leg-length discrepancy, painful antalgic curve, hip contracture or other extra-spinal cause. Vertebral rotation is absent or minimal, and the curve corrects when the cause is removed or on side-bending. | Treatment is directed at the underlying cause. It should not be confused with a fixed structural scoliosis. |
| Structural | Fixed vertebral deformity with rotation and reduced flexibility. Causes include idiopathic, congenital, neuromuscular, syndromic, mesenchymal, degenerative and other spinal disorders. | Requires assessment of progression, neurological status, curve balance and the underlying disease. |
Idiopathic scoliosis is the commonest structural type and is diagnosed after exclusion of congenital vertebral anomalies, neuromuscular disease, syndromic disorders and…