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.
2015
Savarino, L; Greggi, T; Martikos, K; Lolli, F; Greco, M; Baldini, N.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/138821
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