Chromium Metal Ion Release During Instrumented Spinal Surgery in Children

Study Design. Prospective 2-year study with operative sampling and in-vitro analysis of chromium ions following spinal surgery in children. Objectives. To measure metal ion levels at preoperative, intraoperative, and postoperative times to determine patterns of metal ion release during instrumented spinal surgery. Summary of Background Data. Raised serum metal ion levels are reported following instrumented spinal fusion in adolescent idiopathic scoliosis. The authors noted raised chromium levels in patients receiving implants that did not contain chromium. This prompted further work to establish the source. The electrosurgery tips used were discovered to contain 17% chromium. Methods. Chromium, cobalt, and titanium levels were measured before, during, and after surgery in serum and local intraoperative fluid samples in 11 children undergoing posterior instrumentation for scoliosis. Administered drugs, cell-saver fluids, and intraoperative fluids, both local and intravenous, were investigated to exclude these as sources of chromium ions. An in-vitro study was also performed to elucidate sources of intraoperative chromium ions. Results. High chromium levels were detected in all samples from the wound irrigation fluid prior to insertion of metal implants. Immediate postoperative chromium serum ion levels were also elevated and returned to baseline by day 30. In-vitro sampling of fluids from test models using electrosurgery revealed high levels of chromium ions Conclusion. This finding of high chromium metal ion concentrations in intraoperative and early postoperative samples provides evidence of chromium release during the dissection phase of spinal surgery. This challenges existing beliefs that metal ion release occurs solely due to implants and now implicates the electrosurgery electrode tips as a source of raised chromium ion levels. Thorough irrigation of the operative site after the dissection phase of surgery to both dilute and reduce the intraoperative chromium ion load is suggested. Alternative electrosurgery electrode tips or other methods to coagulate during surgery could be considered. Level of Evidence: 2