A defective, normal or enhanced hemostasis has been reported in Duchenne muscular dystrophy (DMD). A retrospective analysis of intra-and postoperative (up to 36 h) estimated blood losses was performed in 156 patients undergoing spinal surgery for: DMD (n = 31), idiopathic scoliosis (IS) (n = 70), poliomyelitis (n = 10), cerebral palsy (CP) (n = 28), spinal muscular atrophy (SMA) (n = 17). Platelet aggregation and bleeding times were also investigated in DMD patients. Immunohistochemistry for dystrophin was performed in platelets, megakaryocytes and blood vessels of normal tissues. DMD patients showed significantly higher intraoperative estimated blood losses (DMD: 3495+/-890 ml; IS: 2269+/-804 ml; poliomyelitis: 2582+/-1252 ml; CP: 2071+/-683 ml; SMA: 2464+/-806 ml; P < 0.05), while postoperative blood losses were similar among different groups. Higher estimated blood losses in DMD were independent of the duration of surgery, body weight, gender, age, vertebral levels or preoperative Cobb angle. DMD children had significantly prolonged bleeding times, but retained normal platelet function. From control samples dystrophin was expressed in vascular smooth muscle cells, but not in platelets. DMD appears to be characterized by immediate bleeding during highly-invasive surgery and increased bleeding time without platelet abnormalities. Considering dystrophin expression in normal vascular smooth muscle cells, these results altogether suggest a selective defect of primary hemostasis in DMD, likely to be due to impaired vessel reactivity.