Prolo D J, Pedrotti P W, White D H
Neurosurgery. 1980 May;6(5):529-39. doi: 10.1227/00006123-198005000-00006.
The use of allogeneic human bone, dura, and fascia has achieved an enduring and accelerating role in the augmentation of spinal fusions and the repair of skeletal and dural defects. Primary sterilization of these nonviable cadaveric tissues magnifies the potential sources and ensures the microbiological sterility of the implant. Subsequent lyophilization facilitates preservation and distribution and reduces the immunogenicity of the graft. The evaluation of gaseous ethylene oxide (EO) as a sterilant was suggested by the delerious effects of alternative methods. Through a series of experiments, the following properties of EO sterilization were studied: (a) surface and interstitial sterilization; (b) the diffusion of EO into tissue, the formation of the reaction products ethylene chlorohydrin (EC) and ethylene glycol (EG), and the desorption of all three from tissues; (c) lyophilization and aeration in the removal of residues; and (d) minimization of residues through pretreatment. Gaseous EO is a very effective surface sterilant of wet bone, dura, and fascia and does not grossly alter these tissues. Its partial penetration through compact bone renders it less reliable for an interstitial antimicrobial effect, unless access to the interior is provided by serial openings. The toxicity of EO, EC, and EG mandates the desorption through lyophilization of these compounds (EC and EG are formed during sterilization with EO). Before sterilization, bone must be rid of marrow by vigorous irrigation with deionized water. The resultant reduction of the number of cells and of the available chloride decreases antigenicity and the formation of EC. Freeze-drying for more than 72 hours, in some cases augmented by prolonged aeration at room temperature, reduces EO, EC, and EG to acceptable levels. The accurate assay of residues in tissue requires acetone extraction for gas chromatography on rehydrated tissues because extraction of dry tissues gives falsely low results. Rigorous adherence to a protocol incorporating these findings justifies the acceptance of gaseous EO as a safe, relatively rapid, and inexpensive sterilant of bone and soft tissues.
异体人骨、硬脑膜和筋膜在增强脊柱融合以及修复骨骼和硬脑膜缺损方面发挥着持久且日益重要的作用。对这些无活力的尸体组织进行初步灭菌可扩大潜在来源，并确保植入物的微生物无菌性。随后的冻干处理便于保存和分发，并降低移植物的免疫原性。由于替代方法存在有害影响，因此有人建议评估气态环氧乙烷（EO）作为一种消毒剂。通过一系列实验，研究了环氧乙烷灭菌的以下特性：（a）表面和间隙灭菌；（b）环氧乙烷向组织内的扩散、反应产物氯乙醇（EC）和乙二醇（EG）的形成以及这三种物质从组织中的解吸；（c）冻干和通气以去除残留物；（d）通过预处理将残留物降至最低。气态环氧乙烷是湿骨、硬脑膜和筋膜非常有效的表面消毒剂，且不会对这些组织造成严重改变。它对密质骨的部分穿透使得其间隙抗菌效果不太可靠，除非通过连续开口进入内部。环氧乙烷、氯乙醇和乙二醇的毒性要求通过冻干使这些化合物解吸（氯乙醇和乙二醇是在用环氧乙烷灭菌过程中形成的）。灭菌前，必须用去离子水大力冲洗骨骼以去除骨髓。由此减少的细胞数量和可利用的氯离子可降低抗原性和氯乙醇的形成。冻干72小时以上，在某些情况下通过在室温下延长通气时间，可将环氧乙烷、氯乙醇和乙二醇降至可接受水平。对组织中残留物进行准确测定需要对复水后的组织进行丙酮萃取以用于气相色谱分析，因为对干燥组织进行萃取会得出错误的低结果。严格遵守包含这些发现的方案证明气态环氧乙烷可作为骨骼和软组织的一种安全、相对快速且廉价的消毒剂被接受。
