BACKGROUND Spinal instrumentation can be associated with complications, including implant loosening. Hitherto, implant loosening has mainly been attributed to mechanical overload. OBJECTIVE To examine the role of low-grade infections as the cause of implant failure in suspected aseptic implant loosening following spinal instrumentation. METHODS A prospective single center observational study was performed. All patients who had revision surgery following spinal instrumentation between August 2015 and February 2018 were screened. Patients with revision surgery due to screw loosening on the computed tomograhy scan constituted the study group. Patients in which the screws where not loosened but removal was performed for other reasons formed the comparison group. Intraoperative swabs were taken and sonication was performed with the explanted material. Results of microbiological cultivation were analyzed. RESULTS A total of 59 patients were included in the study group and 34 in the comparison group. In the study group in 42.4% of the cultures a bacterium was detected, while in the comparison group only in 17.6%. 84%, and 83.3% of these germs were detected by sonication in the study and comparison group, respectively. The rate of positive cultures was significantly higher in the study group compared to the comparison group (P = .001). The most frequent bacterium cultivated in both groups was Propionibacterium acnes, followed by Staphylococcus species. CONCLUSION For patients with screw loosening a high level of suspicion for a low-grade infection should be raised. Cultures should be performed from the sonication fluid of the explanted devices in all patients with symptomatic screw loosening.

中文翻译：

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脊柱器械治疗后的低度感染和植入失败：一项前瞻性比较研究

背景技术脊柱器械可能与并发症相关，包括植入物松动。迄今为止，种植体松动主要归因于机械过载。目的 研究低度感染作为导致脊柱内固定后疑似无菌植入物松动的植入物失败原因的作用。方法 进行了一项前瞻性单中心观察性研究。筛选了所有在 2015 年 8 月至 2018 年 2 月期间接受脊柱内固定术后翻修手术的患者。由于计算机断层扫描中螺钉松动而进行翻修手术的患者构成了研究组。螺钉未松动而是因其他原因拆除的患者作为对照组。取术中拭子并用外植材料进行超声处理。分析微生物培养的结果。结果研究组共纳入59例患者，对照组共纳入34例。在研究组中 42.4% 的培养物中检测到细菌，而在对照组中只有 17.6%。在研究组和对照组中，分别有 84% 和 83.3% 的这些细菌通过超声处理被检测到。研究组的阳性培养率显着高于对照组（P = .001）。两组中最常见的细菌是痤疮丙酸杆菌，其次是葡萄球菌。结论 对于螺钉松动的患者，应高度怀疑其为低度感染。对于所有有螺钉松动症状的患者，都应从外植装置的超声处理液中进行培养。