Purpose: To evaluate the modification of the hump in patients with idiopathic scoliosis after the use of Boston brace and to compare this with the change of the Cobb angle.

Material – Methods: Prospective study of 60 female patients with idiopathic scoliosis who were treated with the application of Boston brace. The average age was 12,8 years ( 9–15 years ) and the average Kisser sign was 1,5. According to King classification 14 (23.5%) patients met the criteria for type I, 21 (35%) for type II, 13 (21.5%) for type III and 12 (20%) for type IV .No patients with type V curves were included. The average Cobb angle was 22°. The patients were reviewed every six months with clinical examination, plain x-rays at erect position and twelve hours after the removal of the brace The patient’s hump was evaluated with the use of a special equipment (formulator), it was imprinted on a chart and the hump gradient was measured. The time of brace application was recorded.

A small group of 15 patient with scoliosis less than 15°, was used as control group. A Boston brace was notn applied to this patients.

T -test and x square test were used for statistical analysis.

Results: The follow-up period was on average 25 months. The brace was applied for 18–20 hours in 24-hours with the tendency of gradual decrease of the time of the application as the patient was getting older. An average decrease of 13,5% of the hump gradient was found after using the Boston brace. This was 17% for King type I, 22.29%, for King type 1lo 9.73% for King type III and 1.19% for King type IV. The average increase of the Cobb ankle was 2, 6 .

Conclusion: The application of the Boston brace in patients with idiopathic scoliosis seems to improve the pattern of the hump, mainly in type II and III patterns and less in type IV.