Blood loss in scoliosis surgery can be significant. Wide spongiosa surfaces predispose for postoperative bleeding. Young patients are not predisposed to DVT even after major surgery .
Although I am interested in DVT prophylaxis but Spinal surgery is not my field. Any how I don't think young patients are not predisposed to DVT unless there is evidence for that. They might be less susceptible to DVT in comparison to adults because they have less predisposing factors of DVT.