Abstract: The effect of a modified Boston Brace with antirotatory blades upon the fate of idiopathic scoliotic (IS) curves, mainly right thoracic with a compensatory left lumbar, is studied. This report refers to curves within the generally accepted range of Cobb angle (20° – 40°) appropriate for conservative treatment.

Method and Material: Out of 166 children suffering IS with Cobb angle > 10°, 67 (61 girls, and 6 boys), having a mean follow up 2,3 years (4 months to 7 years), were studied. A brace of Boston type with antirotatory blades was applied in 36 scoliotic children. The curve type was: 18 thoracic (T) right (rt) + Lumbar (L) left (lt) in children with a mean age 13,1 years, 3 T lt + L rt in children with a mean age 16,3 years, 7 T rt in children with a mean age 13 years and 8 thoracolumbar (TL) rt curves in children with a mean age 12,1 years. Full documentation during the FU had 23 out of the 36 children with 14 T rt + L lt, 1 T lt + L rt (15 in total – double curve group), 4 T rt (thoracic group) and 4 TL curves (thora-columbar group). Traditionally deterioration (increase) or improvement (decrease) of a curve is considered a change of 5ï Cobb compared with the initial reading.

Results: In the 15 double curve group children the mean FU was 28 months. In this group 5 curves were improved, 6 remained stable and 4 were increased. For the 4 thora-columbar curves with a mean FU 8 months, 3 remained stable and 1 improved. For the 4 thoracic curves with a mean FU 9 months, 2 were stable and 2 improved. During the final FU of the above 23 scoliotic children, when the assessment of Cobb angle was made with children out of the brace, 8 curves were improvement, 11 remained stable and 4 deteriorated (one patient out of 4 (4,3%) was operated upon). All the deteriorated curves were double (T rt + L lt). When the assessment of Cobb angle was made with children in the brace, 10 curves were improved, 12 remained stable and 1 deteriorated

Discussion: The brace treatment affected more the double curves while single curves remained unaffected. Rotation remained unchanged in all curve types except in the lumbar component of double (right thoracic-left lumbar) curves. A composite spiral trunk rotator muscle has been proposed, (consisted of the ipsilateral scapular elevator and rhomboid, the anterior serrated, external oblique and contralateral internal oblique abdominal muscle, (Benninghoff 1985, Wemyss-Holden 1990), which is considered that have an effect on the trunk rotation during gait. Asymmetry of one or more constituent muscles creates scoliosis. These findings are consistent with the view that neuromuscular factors are responsible for the initiation of idiopathic scoliosis. The antirotatory blades of the brace are acting upon the above described composite spiral trunk rotator muscle blocking the deterioration of the scoliotic curve or improving the double curves thus supporting the above aetiologic view. In conclusion the conservative treatment using this brace is beneficially affecting the natural history of the IS in children 12–15 years of age.