The risks that occur in this study are associated with the general risks of spine surgery. Risks associated with allogeneic blood transfusion include allergic reactions, hemolytic reactions, isoimmunization, graft versus host reactions, increased infection rates, and transmission of bloodborne pathogens, including human immunodeficiency virus and hepatitis. Risks associated with the use of a cell saver include a paradoxical increase in blood loss, electrolyte depletion, metabolic acidosis, and hematuria