We reviewed 26 patients with progressive spinal kyphosis due to anterior fusion between the vertebrae. No patient had back pain or any neurological defect. The kyphosis appeared to be progressive until the fusion had included all of the disc. Progression was faster during the adolescent growth-spurt. Kyphosis increased with the number of discs involved, from one to six, and the extent of fusion within each disc. In six of the nine cases treated by spinal bracing, progression of the kyphosis was arrested.