Han Jo Kim, Marinus de Kleuver, Keith Luk
Kenneth Cheung, Larry Lenke
Lenke 6 curves have structural thoracolumbar/lumbar and main thoracic curves, with thoracolumbar/lumbar curve being larger than the main thoracic curve.
Due to the morphology of type 6 curves lumbar modifiers A and B do not exist.
A minor curve is defined as structural if at least one of the two below criteria are met:
Same definition applies for proximal thoracic curves.
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 "-".
Measurements between 10°-40° is designated as "N".
A measurement larger than 40° is designated as "+".