Long-term storage of small surgical instruments in autoclaved packages

In most operating theatres, unused sterile instruments must be re-sterilized according to preset protocols. Protocols differ among institutions and are not based on strong scientific evidence.

To determine and compare the duration of sterility of small instruments packaged in double-layered linen versus plastic-paper envelopes after autoclaving.

Two groups of orthopaedic screws were simultaneously sterilized by autoclaving. In Group 1, each screw was packaged in a double-wrapped linen pack. The screws in Group 2 were individually packaged in an inner wrap of paper and an outer plastic-paper envelope that is commercially available. Unwrapped screws in Group 3 served as controls. During the first 48 weeks, five packages were randomly taken from each group, and from 48 weeks to 96 weeks, 20 packages were taken at random and sent for microbial culture. Five screws from Group 3 were also randomly picked with each sample.

Up to 96 weeks, no organisms were cultured from any sample from Groups 1 and 2. Almost all samples from Group 3 grew several species of bacteria.

For small metal instruments, autoclaved packages in double-wrapped linen or double-wrapped plastic-paper combinations can be stored safely for at least 96 weeks.