- Subject has no factors that would put the subject at an additional risk for intra-operative or postoperative bleeding. This includes underlying disorders of the coagulation cascade (eg, hemophilia), disorders that affect platelet count or function (eg, Von Willebrand's disease), as well as administration of any anti-platelet or anti-coagulant medication in the 7 days prior to surgery, or any history of anticoagulant or aspirin use, that in the view of the neurosurgeon or neurologist would place the subject at an increased risk for intra-operative or postoperative bleeding.