This is a brace worn only at night, which takes advantage of total muscular relaxation during sleep. It was first used in the mid-1980s and for several years it offered hope for the correction of light to medium scoliosis without major rotation.
It is made on a mold of thermoplastic material, usually polyethylene or polypropylene, lined with Plastazot foam. The mold is taken at the maximum position of over-correction.
Due to the elasticity of scoliosis, reinforced by muscular relaxation during sleep, and with suitable tensioning of the straps, great lateral forces are exerted to the top vertebra, resulting in partial correction of the curve.
It has a small effect on rotation, even with the placement of an internal pad, provided this is clearly constructed for the correction of the lateral shift, with forces depleting at the height of the top vertebra.
Following research over years by SRS (Scoliosis Research Society) concerning the relative effects of wearing Charleston and Boston braces at night, it was ascertained that there is no substantial difference between them. These results reduced the interest of orthopedic surgeons as far as their use is concerned.