Serum titanium, niobium, and aluminum levels after instrumented spinal arthrodesis in children

STUDY DESIGN. A prospective cohort study. OBJECTIVE. To determine serum titanium, niobium, and aluminum levels in pediatric patients within the first postoperative year after instrumented spinal arthrodesis. SUMMARY OF BACKGROUND DATA. Instrumented spinal arthrodesis is a common procedure to correct scoliosis and kyphosis. Titanium-based instrumentation is increasingly favored due to enhanced biomechanical properties, but concerns have arisen regarding metal debris release and the potential for local and systemic complications. METHODS. The pattern of systemic metal release over time was evaluated by measuring serum titanium, niobium, and aluminum levels preoperatively and 1 week, 1 month, 6 months, and 12 months after instrumented spinal arthrodesis using a titanium alloy. Serum metal levels were measured using high-resolution inductively coupled plasma mass spectrometry. RESULTS. Thirty-two patients were included in the study group. Mean age at surgery was 14.7 years. Preoperative and postoperative concentrations of serum titanium and niobium were significantly different (P = 0.0001). Median postoperative serum concentrations of titanium and niobium were elevated 2.4- and 5.9-fold above the normal range respectively with 95% and 99% of samples elevated postoperatively. A significant and rapid rise in serum titanium and niobium levels was observed within the first postoperative week, after which elevated serum levels persisted up to 12 months. CONCLUSION. We report abnormally elevated serum titanium and niobium levels in patients with titanium-based spinal instrumentation up to 12 months. The long-term systemic consequences of debris generated by wear and corrosion of spinal instrumentation is unclear but concerning, particularly as these implants inserted into the pediatric population may remain in situ for beyond 6 decades.Thomas P. Cundy, Georgia Antoniou, Leanne M. Sutherland, Brian J.C. Freeman and Peter J. Cund