Authors of section

Authors

Han Jo Kim, Marinus de Kleuver, Keith Luk

Executive Editors

Kenneth Cheung, Larry Lenke

General Editor

German Ochoa

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Lenke 1

Lenke 1 curves

Lenke 1 curves are one where the major curve (the curve with the largest Cobb angle) is in the main thoracic region while the proximal thoracic and thoracolumbar are non-structural.

Scoliosis Lenke classification AIS

A minor curve is defined as structural if at least one of the two below criteria are met:

  • Residual curve greater than or equal to 25 ° on supine bending radiograph
  • T2 – T5, T10-L2 kyphosis greater than or equal to 20 ° (regardless of coronal flexibility)

The left X-rays show a 13 year old female with Lenke 1A curve consisting of a:

  • 40° minor PT curve, correcting to 3° on side bending
  • 74° major MT curve, correcting to 49° on side bending
  • 42° minor TL/L curve, correcting to 2° on side bending

As the residual PT and TL/L curves are less than 25° in bending radiographs they are non-structural.

Scoliosis Lenke classification AIS

Lumbar modifiers

The lumbar modifier is determined by drawing a vertical line from the center of the sacrum.

Lumbar modifier A is designated if this line lies between the pedicles at the apical level of the lumbar curve.

Scoliosis Lenke classification AIS

Lumbar modifier B is designated if this line touches the apical vertebral pedicle.

definition

Lumbar modifier C is designated if this line does not touch any part of the vertebral body or pedicle at the apex.

Scoliosis Lenke classification AIS

Sagittal modifiers

The sagittal modifiers are determined from the lateral radiograph from T5-T12. A measurement less than 10° is designated as "-".

Scoliosis Lenke classification AIS

Measurements between 10°- 40° is designated as "N".

Scoliosis Lenke classification AIS

A measurement larger than 40° is designated as "+".

Scoliosis Lenke classification AIS