No irradiant techniques of analysis of deformations of the spine, by surface topography, have been developed with a view to detecting scoliosis and monitoring its progression during growth. The objective of our work was to study the evolution of back surface topography parameters by BIOMOD TM-L in adolescents with idiopathic scoliosis treated with plaster and progressive felting. Children with severe idiopathic scoliosis, for which a plaster more felting treatment before a brace was indicated, and has received a topographic and radiological acquisition before and after the realization of plaster, and up to one year after the start of treatment, were included. The main endpoint was the change of thoraco-lumbar variable in the transverse plane measured by BIOMOD TM-L at T0 (before felting), T1 (after felting) and T2 (one year before the beginning of treatment). Twenty-one children (mean age: 13) were included. There is a significant decrease of the thoraco-lumbar gibbosity measure by BIOMOD TM-L in adolescent with scoliosis treated with plaster more felting, at T0, T1 and T2 ( P = 0.0007). The medians of these gibbosity were of 8,0° (IC 95% [6,15–8,73]), 4,0° (IC 95% [3,37–5,88], rank sum diff = 20) ( P adjusted = 0.0008), and 4,0° (IC 95% [3,64–5,98], rank sum diff = 16) ( P adjusted = 0.0094), respectively at T0, T1 and T2. These results are also checked for gibbosity measured clinically by scoliometer, with a significant decrease up to one year after the start of treatment. However, there is no significant difference at one year for the Cobb angle. The treatment with plaster more felting in the adolescent idiopathic scoliosis enables a significant reduction of the clinical rib hump and measured by back surface topography, and up to one year after the start of treatment.