What is the Lenke classification of adolescent idiopathic scoliosis?

Updated: Dec 02, 2020
  • Author: Charles T Mehlman, DO, MPH; Chief Editor: Jeffrey A Goldstein, MD  more...
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Answer

Currently, the Lenke classification system is commonly used to categorize adolescent idiopathic scoliosis. This system, first published in 2001, includes the following three components [69] :

  • Curve type (1, 2, 3, 4, 5, or 6)
  • Lumbar spine modifier (A, B, or C)
  • Sagittal thoracic modifier (–, N, or +)

On coronal and sagittal radiographs, the six types specified by Lenke et al have specific characteristics that distinguish structural and nonstructural curves in the proximal thoracic (PT), main thoracic (MT), thoracolumbar (TL), and lumbar (L) regions. [69] Regional curves are measured, the major curve is identified, and a determination is made as to whether the minor curve is structural. The curve is then assigned to the appropriate numeric type (1 through 6).

The lumbar spine modifier is based on the relation of the center sacral vertical line (CSVL) to the apex of the curve. If the CSVL passes between pedicles of apical lumbar vertebrae, the modifier A is assigned; if it touches a pedicle, the modifier B is assigned; and if it does not touch apical lumbar vertebrae, the modifier C is assigned.

The sagittal thoracic modifier is based on the sagittal Cobb angle from T5 to T12. If the angle is less than 10º (hypokyphotic), the modifier – is assigned; if it is 10-40º (normal), the modifier N is assigned; and if it exceeds 40º (hyperkyphotic), the modifier + is assigned.


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