Platelet function in adolescent idiopathic scoliosis.

Recent studies have reported abnormal platelet morphology and function in patients with adolescent idiopathic scoliosis. These abnormalities include increased platelet size and dense body numbers, abnormal aggregation, thromboxane A2 synthesis, serotonin release to adenosine diphosphate and epinephrine stimulus, and decreased myosin-adenosine-triphosphatase-specific activity. It was postulated that a membrane-specific defect in calcium transport may be partially responsible for the abnormalities found. In response to a suggestion in the literature that platelet screening could be clinically useful in scoliosis evaluation as well as in basic research of its pathophysiology, a study was performed to evaluate platelet morphology, biochemistry, and function in patients with adolescent idiopathic scoliosis. Platelets from nine volunteers with adolescent idiopathic scoliosis were compared with cells from a control group of nine patients. No significant differences in measured platelet parameters were noted between adolescent idiopathic scoliosis patients and control groups. Platelets from both groups demonstrated normal aggregation and release patterns with all agents except for a mild decreased aggregation and secretion response to epinephrine. No significant differences were noted in serotonin or adenine nucleotide levels. No significant ultrastructural differences were noted. Earlier findings of an abnormal aggregation and secretion response to adenosine diphosphate, increased numbers of dense bodies, or increased intracellular calcium could not be confirmed. On the contrary, we found normal, if not slightly decreased, numbers of dense bodies per platelet and calcium levels that were not different from controls.