STUDY DESIGN:: Case-control study. OBJECTIVE:: To verify whether metal ions in the serum of patients bearing spinal stainless steel instrumentation, were elevated over the long-term following implantation of stainless steel prostheses, and to determine whether these levels could predict potential unfavorable outcomes. SUMMARY OF BACKGROUND DATA:: Instrumented spinal arthrodesis, the standard procedure to correct scoliosis, routinely remains in situ for the patient lifetime. Elevated metal ion levels have been reported at short-term follow-up, but the long-term status, possibly related to systemic toxic effects, is unknown. METHODS:: Twenty-two patients treated for scoliosis with posterior spinal arthrodesis using stainless steel instrumentation were included. Minimum follow-up was 10 years. Oswestry Disability Index (ODI) and Visual analog scale (VAS) were recorded. Chromium (Cr) and nickel (Ni) levels were measured (ng/ml) and compared with levels in a control group including thirty healthy subjects. A ROC curve was calculated based on the clinical assessment (pain, disability) and the X-ray picture, the cut-off values for the parameters were settled, and the ion testing potential was considered as a surrogate marker of failure. RESULTS:: Chromium was significantly increased in patients, compared with controls (P=0.018). A remarkable Cr release without any clinical-radiological sign was recorded in some female patients. A high specificity (93%), positive likelihood ratio (7.00) and overall accuracy (77%) were calculated for chromium: this indicates a high risk of failure when the levels exceeded the cut-off value, which was 0.6▒ng/ml. No significant difference between groups was found for Nickel (P=0.7). CONCLUSIONS:: Chromium testing is suggested as a reliable marker for the malfunctioning assessment, and as a support for standard procedures, especially with doubtful diagnosis. Furthermore, high levels of Cr ions were observed in females. This finding deserves attention especially when counseling young fertile women.
Long-term Systemic Metal Distribution in Patients With Stainless Steel Spinal Instrumentation. A Case-control Study
BALDINI, NICOLA
2015
Abstract
STUDY DESIGN:: Case-control study. OBJECTIVE:: To verify whether metal ions in the serum of patients bearing spinal stainless steel instrumentation, were elevated over the long-term following implantation of stainless steel prostheses, and to determine whether these levels could predict potential unfavorable outcomes. SUMMARY OF BACKGROUND DATA:: Instrumented spinal arthrodesis, the standard procedure to correct scoliosis, routinely remains in situ for the patient lifetime. Elevated metal ion levels have been reported at short-term follow-up, but the long-term status, possibly related to systemic toxic effects, is unknown. METHODS:: Twenty-two patients treated for scoliosis with posterior spinal arthrodesis using stainless steel instrumentation were included. Minimum follow-up was 10 years. Oswestry Disability Index (ODI) and Visual analog scale (VAS) were recorded. Chromium (Cr) and nickel (Ni) levels were measured (ng/ml) and compared with levels in a control group including thirty healthy subjects. A ROC curve was calculated based on the clinical assessment (pain, disability) and the X-ray picture, the cut-off values for the parameters were settled, and the ion testing potential was considered as a surrogate marker of failure. RESULTS:: Chromium was significantly increased in patients, compared with controls (P=0.018). A remarkable Cr release without any clinical-radiological sign was recorded in some female patients. A high specificity (93%), positive likelihood ratio (7.00) and overall accuracy (77%) were calculated for chromium: this indicates a high risk of failure when the levels exceeded the cut-off value, which was 0.6▒ng/ml. No significant difference between groups was found for Nickel (P=0.7). CONCLUSIONS:: Chromium testing is suggested as a reliable marker for the malfunctioning assessment, and as a support for standard procedures, especially with doubtful diagnosis. Furthermore, high levels of Cr ions were observed in females. This finding deserves attention especially when counseling young fertile women.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.