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 4

Lenke 4 curves

Type 4 curves have structural proximal thoracic, main thoracic, and thoracolumbar/lumbar curves (triple major).

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 15 year old female with Lenke 4C curve consisting of a:

  • 40° minor PT curve, correcting to 29° on side bending
  • 68° major MT curve, correcting to 46° on side bending
  • 57° minor TL/L curve, correcting to 26° on side bending

Both the PT and the TL/L curves are structural.

Scoliosis Lenke classification AIS

Lumbar modifiers

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.

Scoliosis Lenke classification AIS

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

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