McPhee I Bruce, Swanson Cheryl E
Division of Orthopaedics, University of Queensland, Brisbane, Australia.
Spine (Phila Pa 1976). 2007 Aug 15;32(18):1963-8. doi: 10.1097/BRS.0b013e318133aa0d.
Case-control study.
To determine whether metal ion concentrations are elevated in patients with spinal instrumentation.
Studies have shown that serum and urinary levels of component metal ions are abnormally elevated in patients with total joint arthroplasties. Little is known of metal ion release and concentrations in patients with spinal instrumentation.
The study group consisted of patients who had undergone spinal instrumentation for various spinal disorders with a variety of stainless steel implants, 5 to 25 years previously. A group of volunteers without metal implants were controls. All subjects were tested for serum nickel, blood chromium, and random urine chromium/creatinine ratio estimation.
The study group consisted of 32 patients with retained implants and 12 patients whose implants had been removed. There were 26 unmatched controls. There was no difference in serum nickel and blood chromium levels between all 3 groups. The mean urinary chromium/creatinine ratio for patients with implants and those with implants removed was significantly greater than controls (P < 0.001). The difference between study subgroups was not significant (P = 0.16). Of several patient and instrumentation variables, only the number of couplings approached significance for correlation with the urine chromium excretion (P = 0.07).
Spinal implants do not raise the levels of serum nickel and blood chromium. There is evidence that metal ions are released from spinal implants and excreted in urine. The excretion of chromium in patients with spinal implants was significantly greater than normal controls although lower where the implants have been removed. The findings are consistent with low-grade release of ions from implants with rapid clearance, thus maintaining normal serum levels. Levels of metal ions in the body fluids probably do not reach a level that causes late side-effect; hence, routine removal of the implants cannot be recommended.
病例对照研究。
确定脊柱内固定患者体内金属离子浓度是否升高。
研究表明，全关节置换患者血清和尿液中的金属离子成分水平异常升高。对于脊柱内固定患者体内金属离子的释放及浓度情况，人们了解甚少。
研究组由5至25年前因各种脊柱疾病接受脊柱内固定并使用多种不锈钢植入物的患者组成。一组无金属植入物的志愿者作为对照组。所有受试者均接受血清镍、血铬检测以及随机尿铬/肌酐比值测定。
研究组包括32例保留植入物的患者和12例已取出植入物的患者。有26例非匹配对照组。三组之间血清镍和血铬水平无差异。植入物患者和已取出植入物患者的尿铬/肌酐平均比值显著高于对照组（P < 0.001）。研究亚组之间的差异不显著（P = 0.16）。在多个患者和器械变量中，只有连接件数量与尿铬排泄的相关性接近显著水平（P = 0.07）。
脊柱植入物不会提高血清镍和血铬水平。有证据表明金属离子从脊柱植入物中释放并经尿液排泄。脊柱植入物患者的铬排泄量显著高于正常对照组，不过已取出植入物患者的铬排泄量较低。这些发现与植入物中离子的低水平释放及快速清除一致，从而维持了正常的血清水平。体液中的金属离子水平可能未达到会导致晚期副作用的程度；因此，不建议常规取出植入物。
