Department of General and Visceral Surgery, Bodden-Kliniken Ribnitz-Damgarten, Sandhufe 2, 18311, Ribnitz-Damgarten, Germany.
3+ Chirurgen, Berlin-Spandau, Germany.
Hernia. 2020 Dec;24(6):1345-1359. doi: 10.1007/s10029-020-02272-w. Epub 2020 Sep 25.
In Africa and other Low Resource Settings (LRS), the guideline-based and thus in most cases mesh-based treatment of inguinal hernias is only feasible to a very limited extent. This has led to an increased use of low cost meshes (LCMs, mostly mosquito meshes) for patients in LRS. Most of the LCMs used are made of polyethylene or polyester, which must be sterilized before use. The aim of our investigations was to determine changes in the biocompatibility of fibroblasts as well as mechanical and chemical properties of LCMs after steam sterilization.
Two large-pored LCMs made of polyester and polyethylene in a size of 11 x 6 cm were cut and steam sterilized at 100, 121 and 134 °C. These probes and non-sterile meshes were then subjected to mechanical tensile tests in vertical and horizontal tension, chemical analyses and biocompatibility tests with human fibroblasts. All meshes were examined by stereomicroscopy, scanning electron microscopy (SEM), LDH (cytotoxicity) measurement, viability testing, pH, lactate and glycolysis determination.
Even macroscopically, polyethylene LCMs showed massive shrinkage after steam sterilization, especially at 121 and 134 °C. While polyester meshes showed no significant changes after sterilization with regard to deformation and damage as well as tensile force and stiffness, only the unsterile polyethylene mesh and the mesh sterilized at 100 °C could be tested mechanically due to the shrinkage of the other specimen. For these meshes the tensile forces were about four times higher than for polyester LCMs. Chemical analysis showed that the typical melting point of polyester LCMs was between 254 and 269 °C. Contrary to the specifications, the polyethylene LCM did not consist of low-density polyethylene, but rather high-density polyethylene and therefore had a melting point of 137 °C, so that the marked shrinkage described above occurred. Stereomicroscopy confirmed the shrinkage of polyethylene LCMs already after sterilization at 100 °C in contrast to polyester LCMs. Surprisingly, cytotoxicity (LDH measurement) was lowest for both non-sterile LCMs, while polyethylene LCMs sterilized at 100 and 121 °C in particular showed a significant increase in cytotoxicity 48 hours after incubation with fibroblasts. Glucose metabolism showed no significant changes between sterile and non-sterile polyethylene and polyester LCMs.
The process of steam sterilization significantly alters mechanical and structural properties of synthetic hernia mesh implants. Our findings do not support a use of low-cost meshes because of their unpredictable properties after steam sterilization.
在非洲和其他资源有限地区（LRS），基于指南且因此在大多数情况下基于网片的腹股沟疝治疗仅在非常有限的程度上可行。这导致在 LRS 中使用更多低成本网片（LCM，主要是蚊式网片）。使用的大多数 LCM 由聚乙烯或聚酯制成，在使用前必须进行灭菌。我们研究的目的是确定蒸汽灭菌后 LCM 的成纤维细胞生物相容性以及机械和化学性质的变化。
两个大孔聚酯和聚乙烯 LCM（尺寸为 11 x 6 厘米）被切割并在 100、121 和 134°C 下进行蒸汽灭菌。这些探头和未灭菌的网片随后在垂直和水平张力下进行机械拉伸测试、化学分析以及与人类成纤维细胞的生物相容性测试。所有网片均通过立体显微镜、扫描电子显微镜（SEM）、LDH（细胞毒性）测量、活力测试、pH 值、乳酸和糖酵解测定进行检查。
即使从宏观上看，聚乙烯 LCM 在蒸汽灭菌后也会出现严重收缩，尤其是在 121 和 134°C 时。虽然聚酯网片在灭菌后在变形和损坏以及拉伸力和刚度方面没有显示出明显的变化，但只有未灭菌的聚乙烯网片和在 100°C 下灭菌的网片才能进行机械测试，因为其他样本的收缩。对于这些网片，拉伸力大约是聚酯 LCM 的四倍。化学分析表明，聚酯 LCM 的典型熔点在 254 到 269°C 之间。与规格相反，聚乙烯 LCM 不是由低密度聚乙烯组成，而是高密度聚乙烯，因此熔点为 137°C，因此会出现上述明显收缩。立体显微镜证实，与聚酯 LCM 相比，聚乙烯 LCM 在 100°C 下灭菌后已经收缩。令人惊讶的是，两种未灭菌的 LCM 的细胞毒性（LDH 测量）最低，而在用成纤维细胞孵育 48 小时后，特别是在 100 和 121°C 下灭菌的聚乙烯 LCM 的细胞毒性显著增加。葡萄糖代谢在无菌和非无菌聚乙烯和聚酯 LCM 之间没有显示出显著变化。
蒸汽灭菌过程显著改变了合成疝网片植入物的机械和结构特性。我们的研究结果不支持使用低成本网片，因为它们在蒸汽灭菌后性质不可预测。
