Effect of repeated cycles of steam sterilization on the integrity of cannulated surgical screws (original) (raw)
Failure of non-vacuum steam sterilization processes for dental handpieces
The Journal of hospital infection, 2017
Dental handpieces are used in critical and semi-critical operative interventions. Although a number of dental professional bodies recommend that dental handpieces are sterilized between patient use there is a lack of clarity and understanding of the effectiveness of different steam sterilization processes. The internal mechanisms of dental handpieces contain narrow lumens (0·8-2·3mm) which can impede the removal of air and ingress of saturated steam required to achieve sterilization conditions. To identify the extent of sterilization failure in dental handpieces using a non-vacuum process. In-vitro and in-vivo investigations were conducted on commonly used UK benchtop steam sterilizers and three different types of dental handpieces. The sterilization process was monitored inside the lumens of dental handpieces using thermometric (TM) methods (dataloggers), chemical indicators (CI) and biological indicators (BI). All three methods of assessing achievement of sterility within dental h...
Microscopic Analysis of Fractured Screws Used as Implants in Bone Fixation
Journal of Failure Analysis and Prevention, 2014
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Evaluation of stainless steel surgical instruments subjected to multiple use/processing
Infection, Disease & Health, 2018
Background: To determine the effect of multiple use and processing cycles on instrument quality over the life of stainless steel, complex designed clinical surgical instruments. Methods: Steam sterilised surgical instruments due to be discarded from Australian hospitals, because of loss of functionality, were assessed for contaminating protein and bacteria using the bicinchoninic acid protein assay and microbial culture, respectively. Biofilm presence and instrument damage were visually confirmed by scanning electron microscopy (SEM). Instruments were categorised into hinged/serrated, screw, cannulated, flexible, and irregular surfaced (but not hinged) according to their design. Results: Protein contamination ranged from 24 mg on the new screw to 3,756,046 mg contaminating a discarded forceps. The more complex the instrument design the higher the protein contamination. All samples were culture negative, however, biofilm was visually confirmed on 4/8 instruments tested using SEM. SEM also detected soil, holes or black stains on all the instruments. Conclusion: "Ready to use" surgical instruments that underwent multiple uses and processing cycles were contaminated with high amounts of protein, and microscopy revealed the presence of soil, structural damage, black stains and biofilm. While less affected new but multiply processed screws also showed soil and biofilm contamination. These findings highlight the need for further research into determining what is the "life" of stainless steel
Hygiene, 2022
Orthopedic implants, such as screws, are provided in a non-sterile state and must be reprocessed before each use, therefore they may be subjected to multiple reprocessing cycles until they are implanted in the patient. The effect of these various reprocessing cycles on the quality and safety of these implants has been a subject of concern and discussion around the world. In this narrative review, we discuss the four main challenges associated with supplying these non-sterile implants to the same standard, with respect to their quality and safety, as implants that are provided sterile: microbiological contamination (focusing on biofilm), non-microbiological contamination, surface damage, and their acquisition in surgical trays from loaner companies.
Open Forum Infectious Diseases, 2020
Background The acquisition of reusable medical devices through loaner system is a worldwide phenomenon. Single-use implants, such as orthopaedic screws, that remain in the surgical tray are subjected to multiple handling and reprocessing until they are implanted. Exposure to physical, chemical and biological agents may compromise their quality/safety and favor biofilm formation. The aim of this study was to assess the surface integrity and microbiological conditions of patient-ready orthopaedic surgical implants (least used cortical screws), provided through loaner system. Methods After full reprocessing, clinical trays used for small fragment surgery (3,5) provided through loaner system to a large Brazilian teaching hospital were randomly selected between August to November 2019. Trays were opened in a biological safety cabinet and the least frequently used cortical screws (numbers 10 and 38), therefore, the ones most exposed to biological, chemical and physical agents, were random...
Tissue reaction to implants of different metals: a study using guide wires in cannulated screws
European cells & materials, 2009
Cannulated screws, along with guide wires, are typically used for surgical fracture treatment in cancellous bone. Breakage or bending deformation of the guide wire is a clinical concern. Mechanically superior guide wires made of Co-Cr alloys such as MP35N and L605 may reduce the occurrence of mechanical failures when used in combination with conventional (316L stainless steel) cannulated screws. However the possibility of galvanic or crevice corrosion and adverse tissue reaction, exists when using dissimilar materials, particularly in the event that a guide wire breaks, and remains in situ. Therefore, we designed an experiment to determine the tissue reaction to such an in vivo environment. Implant devices were designed to replicate a clinical situation where dissimilar metals can form a galvanic couple. Histological and SEM analyses were used to evaluate tissue response and corrosion of the implants. In this experiment, no adverse in vivo effects were detected from the use of dissi...
Failure strength of bioabsorbable interference screws: effects of in vivo degradation for 12 weeks
Knee Surgery Sports Traumatology Arthroscopy, 2003
We investigated the effect of in vivo degradation for 6–12 weeks on the fixation strength of polylactide bioabsorbable interference screws. Ten bioabsorbable interference screws were used to fix the patellar tendon autograft in ten live sheep knees, which were equally divided into two groups and killed in the 6th or 12th week. The control group consisted of four cadaveric knees. Following the killing of the animals the screws were retrieved and reused to fix patellar tendon grafts in cadaveric sheep knees. Tendon pull-out tests were performed for the partially degraded screws, for the control group, and for the reused screws of the control group. Macroscopic and microscopic examinations of the 6- and 12-week specimens were performed. Tendons pulled-out with an average force of 357±30 N in the cadaveric control group on the first use and with 465±118 N on the second use. The partially degraded screws failed with a mean load of 399±119 N in the 6-week group, and 12-week screws at 447±72 N. No macroscopic sign of degradation was observed on the retrieved screws. Histological examination of the 6 week specimens showed necrotic changes in the tendon around screw contact areas. Healing with granulation tissue was present in the same area in the 12th week. Foreign body reaction or an excessive inflammatory reaction was not observed. In vivo degradation of poly-l-lactide interference screws for 12 weeks thus causes neither a loss in the fixation strength of the screws nor an obvious inflammatory reaction.
Evaluation of the degradation of two bioabsorbable interference screws: an in-vivo study in sheep
Acta Cirúrgica Brasileira
To evaluate in-vivo degradation of two bioabsorbable interference screws. Methods: Twenty-two crossbred Santa Inês ewes were used. A poly-DL-lactide (PDLLA) screw (70%/30%) was inserted in the right pelvic limb, and a PDLLA screw (70%) + β-tri-calcium phosphate (β-TCP) (30%) in the left pelvic limb. Animals were euthanized at one, four, seven and a half and 18 months after surgery. Plain radiography, computed tomography (CT), microCT, and histological analysis were accomplished. Results: PDLLA screw was hypodense at all evaluation moments, but with progressive density increase along the central axis, whereas PDLLA/β-TCP was initially hyperdense and progressively lost this characteristic. No adverse reactions were observed on histological evaluation. Conclusions: The inclusion of β-TCP favors screw degradation since the PDLLA/β-TCP screws evidenced a more intense degradation process than the PDLLA screws at the last evaluation. PDLLA screws showed higher bone production, evident around the screw thread, inside the lateral perforations, and in the central canal, whereas the PDLLA/β-TCP screws presented less bone tissue at the implantation site.