Idiopathic scoliosis (IS) most commonly develops during adolescence, but may present at any age from infancy through adulthood. Patients with IS are evaluated clinically and radiographically to determine whether the deformity is, in fact, idiopathic, to elucidate any symptoms related to the scoliosis, and to characterize the deformity itself. In patients who have not yet reached skeletal maturity, the treatment of IS is often prophylactic, with the aim of preventing the curve from reaching a magnitude that would make continued progression in adulthood likely. Adult patients with IS are most frequently treated because of symptoms, usually back or leg pain. IS is typically treated with anterior or posterior spinal fusion; treatment of very young patients is complicated by the need to allow growth to continue while controlling the scoliosis.