Fig. 21

The first radiological criterion is called “curve pattern compatibility.” Any curve is defined according to the apical level following SRS terminology. Structural curve is not defined directly from the radiograph but from clinical observation and exploration. A clinically defined structural curve is used to be confirmed on the radiograph by certain amount of rotation or vertebral wedging (no matter the Cobb angle). Once the curve/s have been defined, we use a modified Lonstein’s revision of the classical Moe and Kettleson classification. Double major is defined when two structural curves have a Cobb angle not different to 5°. Single curve is used just when there is one single structural curve. One pattern more is defined in the composite group, called “major lumbar or thoracolumbar with minor thoracic.” This is here necessary because a real single lumbar or thoracolumbar is classified as E type and will get a short brace while “major lumbar or thoracolumbar with minor thoracic” is classified B type and will get a long brace. The term structural proximal curve is not only used for thoracic double major curve. A minor structural proximal curve can be observed, primary or secondary to bracing. Sometimes the proximal curve is clearly visible clinically but not easy to confirm radiologically (hidden proximal curve). Clinical signs for a proximal thoracic curve are elevation of the shoulder with a prominence of the trapezium line in combination with a deviation of the spinous processes line and costal prominence in forward bending. The proximal curve can be also a major, combined with a minor structural curve in the main thoracic region