Scientific paper
Effects of resterilization on mechanical properties of polypropylene meshes

https://doi.org/10.1016/j.amjsurg.2005.11.018Get rights and content

Abstract

Background

The re-use of sterile packaged polypropylene meshes in hernia surgery is not recommended by the manufacturers. However, especially in developing and underdeveloped countries, many surgeons are obliged to re-use the mesh pieces after resterilization because of economic problems. The purpose of this study was to determine the effects of ethylene oxide and autoclave resterilization on the mechanical properties of polypropylene meshes.

Methods

Repetitive ethylene oxide gas and autoclave sterilizations were applied to polypropylene meshes (Herniamesh S.r.l., San Mauro, Italy) up to 3 times and the effects on the mechanical properties were examined. Gas resterilizations were applied for 4.5 hours at 55°C, whereas for autoclave resterilizations the specimens were kept at 134°C and 3 atm pressure for 64 minutes. Ethylene oxide gas–sterilized samples were labeled as Gn and autoclave-sterilized samples were labeled as An. Effects of the resterilizations on maximum load (Fmax), elongation at maximum load (ΔL), and energy required for complete failure of the specimen (E) were measured.

Results

Fmax in the groups showed no significant differences. ΔL values of groups A2, A3, and G3 were found to be significantly lower in comparison with the control group, whereas differences between the control group and other groups were not statistically significant. E values of A2 and A3 groups were significantly lower than that in the control group (P < .05), whereas the differences between the control group and other groups were not found to be statistically significant. No significant variations were determined between samples sterilized 1, 2, or 3 times in scanning electron microscopy micrographs, however, small irregularities were observed on autoclaved samples.

Conclusions

Single use of polypropylene meshes is always recommended because of biocompatibility and infection risks. However, if re-use of the open packages is needed, ethylene oxide sterilization is preferred over autoclave sterilization. If ethylene oxide sterilization is not available then 1 cycle of resterilization with an autoclave can be used.

Section snippets

Mesh

An undyed, knitted, pure polypropylene mesh piece, 30 × 30 cm in size, that originally was sterilized by the manufacturer (Herniamesh S.r.l.), was used.

Gas sterilization

Gas sterilizations were performed in the eto.krt 135 device (Ekol Medical, Ankara, Turkey). Ethylene oxide gas was applied to the specimens for 4.5 hours at 55°C for each sterilization process. After the sterilization phases, aeration was applied to the samples for 12 hours. For repetitive sterilizations, the same procedure was performed on the

Results

The Fmax values of each group are shown in Table 1. Although the values in the control group and the other groups were somewhat different, these differences were not found to be statistically significant (P > .05).

The ΔL values of each group are shown in Table 1. Groups A2, A3, and G3 were found to have significantly lower values in comparison with the control group (P < .05), whereas differences between the control group and other groups were not statistically significant (P > .05).

The E

Comments

Polypropylene meshes are the preferred material for tension-free inguinal hernioplasties and ventral hernia repairs in many centers today [7], [8], [9], [10]. These meshes are available in sterile packages for single use. However, because it is cheaper, some surgeons prefer cutting 1 large piece of mesh into several smaller pieces and to re-use the pieces after resterilization. Although it is not recommended by the manufacturers mainly because of the risk for infection, recent studies have

Conclusions

In summary, ethylene oxide sterilization results in minimal changes to the mechanical properties of polypropylene meshes according to our testing methods. It is preferable to use autoclave sterilization, which may be used for a single cycle if gas sterilization is not available. However, our findings apply only to the mechanical properties of polypropylene meshes and do not apply to the potential issues of infection or biocompatibility in patients.

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