Fig. 1

Evolution of elongation concepts along the vertical axis. At the time of the first Sayre’s plaster cast, cervical suspension and body weight realize a bipolar overall elongation. With the Milwaukee brace, the elongation is internal between pelvic girdle and cervical collar. With the Lyon brace, elongation occurs between the pelvic and shoulder girdle with equal distribution of forces on the right and on the left. The elongation requires precise adjustment of the brace during the growth of the child. Other TLSO braces introduce a new concept described by Chêneau as “cherry stone effect” with stretching upwards between pelvis and rib cage. The existence of windows in the brace do not affect elongation. In contrast, with the new Lyon brace, axial elongation type “mayonnaise tube” is achieved by the simultaneous clamp of the two hemi polycarbonate pieces and requires the integrity of the external tube wall