Hybrid spinal implants that combine cobalt-chromium rods with titanium screws have recently gained popularity in the treatment of scoliosis owing to their enhanced biomechanical properties. Our team is currently conducting a prospective study to determine the serum metal ion levels (chromium, cobalt, titanium, and nickel) of patients undergoing posterior spinal instrumentation for adolescent idiopathic scoliosis or neuromuscular scoliosis in patients that have cobalt-chromium rods with titanium screws and patients that have stainless steel rods with stainless steel screws. The results of this study will optimize treatment for scoliosis.