This study conducted sterilization testing under different conditions using different strains for sterilization and crushing, the intermediate healthcare waste treatment phase, and proposed strategies for diversifying corresponding facilities in addition to promoting their installation. Five indicator microorganisms were selected to test the sterilization efficiency of steam, microwave, and chemical methods. Steam sterilization testing was conducted in accordance with legal and technological standards, microwave testing was carried out according to the legal standard, and chemical sterilization employed three typical compounds. Steam and microwave sterilization achieved 99.9999 % inactivation rates for all five strains under both conditions used; whereas under the chemical sterilization analyses, sodium hypochlorite (1000 ppm) failed to meet the inactivation requirement of the fungal strain Candida albicans, requiring further investigation. Based on these findings, this study presents strategies for diversifying sterilization·crushing facilities and promoting their installation.

BACKGROUND: 3D printing, which is becoming ever more widespread in orthopedic surgery, requires specific materials. Polylactic acid (PLA) is the most widely used in general-purpose 3D printing, but its thermosensitivity can be incompatible with sterilization. Even so, it is easy to use, inexpensive, non-toxic and biodegradable. Controversy surrounds its use. 3D printing of directly sterilizable PLA parts according to surgeons\' needs would be highly advantageous, but doubts remain. We therefore performed an in vitro study to determine which PLAs resist steam sterilization regarding deformation.
OBJECTIVE: The study hypothesis was that, depending on make and shape, 3D-printed PLA parts can retain their properties after steam sterilization.
METHODS: We selected 4 makes of PLA and used each to print 4 simple cubes and 4 complex shapes corresponding to cuboid bones. They were subjected to steam sterilization under normal French hospital conditions. The size of the cubes was measured before and after sterilization, using a digital caliper.
RESULTS: Cuboid parts in HT-PLA and PLA-WANAO showed mean deformation of -0.02mm and -0.4mm, respectively after sterilization, the differences being non-significant (p=0.679 and p=0.241, respectively). Cuboid parts in PLA-SUNLU and PLA-G3D showed significant mean deformation: respectively, -1.37mm (p=0.026) and -35.03mm (p>0.001). Cubes in all types of PLA showed significant mean deformation: HT-PLA, -0.61mm (p=0.004); PLA-SUNLU, -2.70mm (p=0.002); PLA-G3D, -28.64mm (p>0.001); and PLA-WANAO, -1.33mm (p=0.010).
CONCLUSIONS: The study confirmed recent findings that steam sterilization is feasible with certain PLA-printed parts, with deformations less than 1mm, and that choice of PLA is crucial for success. Computer-designed objects (here, cubes) did not resist sterilization without significant deformation. Analysis of resistance to various stresses was not performed, and therefore it cannot be claimed that the process could be used other than for printing anatomic parts. Use of 3D printing in French hospitals is probably a real source of innovation and improvement in care quality; however, a legal framework needs establishing for the use of 3D-printed parts, to ensure patient safety and promote research in this field.
METHODS: III; prospective in vitro study.

Computer-assisted surgery with three-dimensional (3D) printed surgical guides provides more accurate results than free-hand surgery. Steam sterilization could be one of the factors that affect the dimensions of surgical guide resin materials, leading to inaccuracies during surgeries. The purpose of this study was to evaluate the effects of steam sterilization on the dimensional accuracy of indication-specific hollow cube test bodies, manufactured in-house using Class IIa biocompatible resin materials (proprietary and third-party). To evaluate the pre- and post-sterilization dimensional accuracy, root mean square (RMS) values were calculated. The results indicate that, in all the groups, steam sterilization resulted in an overall linear expansion of the photopolymeric resin material, with an increase in outer dimensions and a decrease in inner dimensions. The effects on the dimensional accuracy of test bodies were not statistically significant in all the groups, except PolyJet Glossy (p > 0.05). The overall pre- and post-sterilization RMS values were below 100 and 200 µm, respectively. The highest accuracies were seen in proprietary resin materials, i.e., PolyJet Glossy and SLA-LT, in pre- and post-sterilization measurements, respectively. The dimensional accuracy of third-party resin materials, i.e., SLA-Luxa and SLA-NextDent, were within a comparable range as proprietary materials and can serve as an economical alternative.

In practice it is claimed that load characteristics influence a surface steam sterilization process. To the best of our knowledge, no information on this topic has been found in the literature. The purpose of this study was to find if a load influences the duration and related characteristics of a surface steam sterilization process. In a case study, every load monitoring using an objective, quantifying steam penetration test was performed during 30 days. This resulted in 98 production processes with load monitoring. The acquired data were analyzed. A relation between the weight of a load and the duration of a surface steam sterilization process has been found. In this case study, it is demonstrated that the process time increases with the weight of the sterilizer load. Additionally, it is concluded that when the duration of a process is longer, diffusion will have a greater effect and steam penetration increases.LAY ABSTRACT: Steam sterilization is applied in most health-care facilities that reprocess medical devices, in pharmaceutical industries, and in labs where specific instrumentation and equipment have to be sterile. Steam sterilization is still not fully understood, as demonstrated in the literature. Our manuscript contributes to understanding the surface steam sterilization process. The information shared in our manuscript demonstrates by a case study that relations exist between the weight of the load which is steam sterilized, the duration of a process, and the steam penetration in a process. A quantitative relation can be used to predict the duration of a process and the steam penetration. It is likely that for other steam sterilizers these relations can be found as well. This is of interest for institutes researching decontamination and sterilization, health-care facilities, developers and manufacturers of medical devices, and committees addressing standards for steam sterilization.

BACKGROUND: Steam sterilization is an essential part of infection prevention. The literature shows that sterilization of medical instruments containing channels is not trivial. Phaco hand pieces have a simple configuration: a device contains a channel with a constant radius. No literature was found indicating whether the sterilization conditions on the inner surface of a phaco hand piece are influenced by the orientation of the hand piece.
OBJECTIVE: To determine whether the orientation of a phaco hand piece influences the results of a sterilization process of this device.
METHODS: A qualitative case study, including experiments, is performed with a protocolled combination of steam sterilizer, process, phaco hand piece, orientation of the phaco hand piece, and wrapping.
RESULTS: In this specific case, the orientation of the hand piece influenced the result of the steam sterilization process; in vertically (upright) oriented phaco hand pieces with free water drainage, sterilization conditions are reproducibly established. In the same process, in horizontally oriented or vertically oriented hand pieces without free drainage, these conditions are not established in a reproducible way.
CONCLUSIONS: In the investigated combination of sterilizer, process, load, loading pattern and wrapping, phaco hand pieces have to be oriented vertically (upright) with free water drainage to obtain steam sterilization conditions on the inner surface. It is likely that instruments with comparable configuration and dimensions will yield comparable results. It is therefore recommended that this issue is considered during the development of medical instruments and during performance qualifications of such instruments.