Scoliosis at less than 30 degrees. Properties of the evolutivity (risk of progression).

In an attempt to find prognostic factors for mild scoliosis, the first clinical and radiologic data of 159 subjects with idiopathic scoliosis less than 30 degrees were correlated with the annual speed of progression estimated graphically by further examinations. Thoracic and double major are more progressive than thoracolumbar and lumbar. The correlation with rate of progression is better for supine angle than for standing angle. Curves with low supine angles are those that have great relative collapse and low risk of progression. Only the rib hump of thoracic and thoracolumbar are correlated with evolutivity. Predictive equations give less approximation for individual prognosis than a previous graphic method, so they are not used. Approximately 73% of scoliosis have evolutivities less than 6 degrees per year and required nocturn corrective treatment.