Platelet aggregation abnormalities in idiopathic scoliosis.

Platelet aggregation studies were performed in 22 adolescent girls with idiopathic scoliosis. Impaired ADP-induced platelet aggregation was found in washed platelets of the 22 patients with idiopathic scoliosis when compared with the controls (76.5% of control values; p less than 0.01). Furthermore, platelets from patients with progressive curves showed a greater degree of abnormality than platelets from those with nonprogressive curves, e.g., 57.6 +/- 22% of control values (p less than 0.001). No significant differences in aggregation could be detected when platelets were aggregated with the ionophore A-23187 in either the absence or the presence of calcium. Platelet aggregation studies in patients with other spinal deformities did not differ from the healthy controls. Because platelets share similar contractile proteins as muscles, the present study suggests that a muscle disorder may play an important pathogenic role in idiopathic scoliosis.