An orthosis for the treatment of congenital, developmental and degenerative spinal deformities or misalignments, including an upper thoracic component adapted to cover part or the whole thorax and made in non-elastic material, a pelvic component adapted to encircle the pelvis and made in elastic-material and reinforced with non-elastic materials, a non-elastic strapping system adapted to encircle the pelvis transversely and providing a stable fitting, resistant to transverse plane rotations and proximal migration, and at least four removable, corrective elastic bands running obliquely around part or all of the body circumference and attach from the thoracic component (right shoulder, left shoulder, right distal thorax, left distal thorax) to posterior-lateral and/or anterior sections of the pelvic component.