The natural history of idiopathic scoliosis.

A clear understanding of the natural history of idiopathic scoliosis is essential for developing effective treatment. The current information on its natural history indicates that a large number of patients have minor degrees of curvature (approximately 100 per 1000 individuals), although only about two per 1000 individuals warrant treatment because of curve progression. A large number of these curves do not increase even without treatment. Prognostic indicators such as growth, menarch, Risser sign, age at diagnosis, and sex are useful for predicting curve progression but are not always precise. Nonpredictive factors include family history, thoracic kyphosis, lumbar lordosis, lumbosacral transitional anomalies, and trunk balance. Future growth potential and curve severity remain the most reliable considerations in predicting the course of the disorder and in devising suitable approaches to treatment.