Abstract
Objective
Assess the surface integrity and microbiological conditions of patient-ready screws in orthopaedic trays that had been multiply reprocessed.
Methods
After full reprocessing, clinical trays used for small fragment surgery provided through a loaner system to a Brazilian hospital were randomly selected during four months. The most (numbers 14, 16 and 18 – Group 1) and least (numbers 10 and 38 – Group 2) frequently implanted screws, therefore, the ones estimated to be the most and least exposed to biological, chemical and physical agents, were randomly removed and subjected to visual inspection (n=126), followed by bacterial culture (n=6 screws/tray, 9 trays), protein test (n=6 screws/tray, 9 trays) and Scanning Electron Microscopy (SEM) (n=2 screws/tray, 9 trays). Positive cultures were subjected to automated bacterial identification and antimicrobial susceptibility tests.
Results
Grooves were detected on 8.7% screws, predominantly in Group 2 (8/11). Residual protein was detected on 96,3%, and there was no statistically significant difference in the amount of protein between the groups (P=0.07). Bacterial growth was identified in 3/54 screws. Surface damage and soil were visualized on all screws subjected to SEM. Extensive biofilms were detected on eight screws, three from Group 1 and five from Group 2.
Conclusion
Recovery of bacteria, biofilm accumulation and surface damage were detected on patient-ready screws. Screws frequently remain in surgical trays for multiple reprocessing; thus they are repeatedly exposed to contamination and damage. These findings point to the need to discuss and review the way these single-use implants are currently made available for surgeries.
Sterilization; Prostheses and implants; Bone screws; Orthopedic procedures; Biofilms; Anti-infective agents; Bacteria
Resumo
Objetivo
Avaliar a integridade da superfície e as condições microbiológicas de parafusos prontos para uso em bandejas ortopédicas após múltiplos processamentos.
Métodos
Após o processamento completo, as bandejas utilizadas em cirurgias de pequenos fragmentos, fornecidas por meio de sistema de consignação/comodato em um hospital brasileiro, foram selecionadas aleatoriamente durante quatro meses. Os parafusos mais utilizados (números 14, 16 e 18 – Grupo 1) e menos utilizados (números 10 e 38 – Grupo 2), portanto, os mais e menos expostos a agentes biológicos, químicos e físicos, foram aleatoriamente removidos e submetidos a inspeção visual (n=126), seguido de cultura bacteriana (n=6 parafusos/bandeja, 9 bandejas), teste de proteínas (n=6 parafusos/bandeja, 9 bandejas) e Microscopia Eletrônica de Varredura (MEV) (n=2 parafusos/bandeja, 9 bandejas). As culturas positivas foram submetidas a métodos automatizados de identificação bacteriana e suscetibilidade antimicrobiana.
Resultados
Foram detectadas ranhuras em 8,7% dos parafusos, predominantemente no Grupo 2 (8/11). Proteína residual foi detectada em 96,3%, e não houve diferença estatisticamente significativa na quantidade de proteína entre os grupos (P=0,07). Crescimento bacteriano foi identificado em 3/54 parafusos. Danos na superfície e presença de sujidade foram visualizados em todos os parafusos submetidos a MEV. Formação de biofilmes extensos foi detectada em oito parafusos, três do Grupo 1 e cinco do Grupo 2.
Conclusão
Recuperação de bactérias viáveis, acúmulo de biofilme e danos na superfície foram detectados nos parafusos prontos para uso. Os parafusos costumam permanecer nas bandejas cirúrgicas e serem submetidos a múltiplos processamento, sendo expostos a contaminação e danos repetidas vezes. Esses achados apontam para a necessidade de discutir e repensar a forma como esses implantes de uso único são atualmente disponibilizados para cirurgias.
Esterilização; Próteses e implantes; Parafusos ósseos; Procedimentos ortopédicos; Biofilmes; Anti-infecciosos; Bacterias
Resumen
Objetivo
Evaluar la integridad de la superficie y las condiciones microbiológicas de tornillos listos para uso en bandejas ortopédicas después de múltiples procesamientos.
Métodos
Después del procesamiento completo, fueron seleccionadas aleatoriamente durante cuatro meses las bandejas utilizadas en cirugías de pequeños fragmentos, proporcionadas mediante el sistema de consignación/comodato en un hospital brasileño. Los tornillos más utilizados (números 14, 16 y 18 – Grupo 1) y menos utilizados (números 10 y 38 – Grupo 2), por lo tanto, los más y menos expuestos a agentes biológicos, químicos y físicos, fueron quitados aleatoriamente y sometidos a inspección visual (n=126), seguido de cultivo bacteriano (n=6 tornillos/bandeja, 9 bandejas), prueba de proteínas (n=6 tornillos/bandeja, 9 bandejas) y microscopía electrónica de barrido (MEB) (n=2 tornillos/bandeja, 9 bandejas). Los cultivos positivos fueron sometidos a métodos automatizados de identificación bacteriana y susceptibilidad antimicrobiana.
Resultados
Se detectaron ranuras en el 8,7 % de los tornillos, predominantemente en el Grupo 2 (8/11). Se detectó proteína residual en el 96,3 % y no se encontró diferencia estadísticamente significativa en la cantidad de proteína entre los grupos (P=0,07). En 3/54 tornillos se identificó crecimiento bacteriano. Se visualizaron daños en la superficie y presencia de suciedad en todos los tornillos sometidos a MEB. En ocho tornillos se detectó la formación de biopelículas, tres del Grupo 1 y cinco del Grupo 2.
Conclusión
Se detectó recuperación de bacterias viables, acumulación de biopelícula y daños en la superficie en los tornillos listos para uso. Los tornillos suelen permanecer en las bandejas quirúrgicas y son sometidos a múltiples procesamientos, donde están expuestos a contaminación y daños repetidas veces. Estos descubrimientos señalan la necesidad de discutir y repensar la forma como estos implantes de uso único se ponen a disposición para cirugía actualmente.
Esterilización; Prótesis e implantes; Tornillos óseos; Procedimientos ortopédicos; Biopelículas; Antiinfecciosos; Bacterias
Introduction
Worldwide, reusable medical devices (RMD), especially those used in orthopaedic surgery, are sourced through loaner systems.(11. Seavey R. Reducing the risks associated with loaner instrumentation and implants. AORN J. 2010;92(3):322-31; quiz 332-4.) Orthopedic surgical boxes additionally include single-use implants, manufactured in stainless steel, such as plates and screws. Although classified as single-use, orthopedic plates and screws are packaged with the other surgical devices in the tray and are subject to multiple sterilization processes until they are implanted. Thus, multiple opportunities exist for exposure to physical, chemical and biological agents resulting in contamination and surface damage.(22. Costa DM, Lopes LK, Vickery K, Watanabe E, Vasconcelos LS, De Paula MC, et al. Reprocessing safety issues associated with complex-design orthopaedic loaned surgical instruments and implants. Injury. 2018;49(11):2005-12.)
The loaner system enables hospitals to access a wide variety of surgical devices in the face of rapid technological advances, but the high turnover of the surgical boxes between various healthcare facilities can hinders their proper management and reprocessing.(11. Seavey R. Reducing the risks associated with loaner instrumentation and implants. AORN J. 2010;92(3):322-31; quiz 332-4.
2. Costa DM, Lopes LK, Vickery K, Watanabe E, Vasconcelos LS, De Paula MC, et al. Reprocessing safety issues associated with complex-design orthopaedic loaned surgical instruments and implants. Injury. 2018;49(11):2005-12.-33. Lopes LK, Costa DM, Tipple AF, Watanabe E, Castillo RB, Hu H, et al. Surgical instruments complex design as barrier for cleaning effectiveness, favouring biofilm formation. J Hosp Infect. 2019;103:e53-60.) While the presentation of screws in racks within the surgical boxes, facilitates their use during surgery, it is not conducive to adequate reprocessing, especially the cleaning stage.(44. Vickery K, Hu H, Jacombs AS, Bradshaw DA, Deva AK. A review of bacterial biofilms and their role in device-associated infection. Infect Dis Health. 2013;18:61-6. Review.)
One of the major problems resulting from improper reprocessing is the formation of biofilm, which consists of an aggregation of sessile cells adhered to a surface, encased in a matrix of extracellular polymeric substances (EPS).(55. Alfa MJ. The “Pandora’s box” dilemma: reprocessing of implantable screws and plates in orthopedic tray sets. Biomed Instrum Technol. 2012;(Suppl):55–9.) Biofilms protect microorganisms against adverse conditions, such as exposure to detergents, disinfectants and sterilizers agents.(22. Costa DM, Lopes LK, Vickery K, Watanabe E, Vasconcelos LS, De Paula MC, et al. Reprocessing safety issues associated with complex-design orthopaedic loaned surgical instruments and implants. Injury. 2018;49(11):2005-12.,33. Lopes LK, Costa DM, Tipple AF, Watanabe E, Castillo RB, Hu H, et al. Surgical instruments complex design as barrier for cleaning effectiveness, favouring biofilm formation. J Hosp Infect. 2019;103:e53-60.,66. Alfa M, Howie R. Modeling microbial survival in buildup biofilm for complex medical devices. BMC Infect Dis. 2009;9:1-14.) On RMD, biofilm develops gradually over successive rounds of exposure to fluids (patient use, precleaning, cleaning, disinfection/sterilization) and drying stages (packing and storage), and is named build-up biofilm.(66. Alfa M, Howie R. Modeling microbial survival in buildup biofilm for complex medical devices. BMC Infect Dis. 2009;9:1-14.,77. Zhong W, Alfa M, Howie R, Zelenitksy S. Simulation of cyclic reprocessing buildup on reused medical devices. Comput Biol Med. 2009;39:568-77.) This is more compact and adherent than the traditional biofilm,(66. Alfa M, Howie R. Modeling microbial survival in buildup biofilm for complex medical devices. BMC Infect Dis. 2009;9:1-14.,88. Vickery K. Special Issue: microbial biofilms in healthcare: formation, prevention and treatment [Editorial]. Materiais (Basel). 2019;12:2001.) which forms under constant wet conditions.(77. Zhong W, Alfa M, Howie R, Zelenitksy S. Simulation of cyclic reprocessing buildup on reused medical devices. Comput Biol Med. 2009;39:568-77.) We aimed to assess the surface integrity and microbiological contamination of patient-ready orthopaedic surgical screws (least and most used cortical screws), provided through the loaner system.
Methods
This study was performed in the Central Sterilizing Service Department (CSSD) a public general teaching hospital (235 beds), in the Midwest region of Brazil, from August to November 2019. Loaned small fragments surgical boxes 3.5 (SFB 3.5) used in orthopedic surgical procedures (fractures) of lower and upper limbs were evaluated. SFB 3.5 consist of surgical instruments and a tray containing cortical and cancellous screws of varying sizes ranging from number 10 to 50.
To prevent interference with hospital surgical routine, the supplying loaner company delivered an extra SFB 3.5 kit once a week. Upon delivery at the CSSD, SFB 3.5 were submitted to all processing steps (reception, cleaning, drying, integrity and functionality assessment, preparation, sterilization and storage) following the hospital protocol. The sterilization process was saturated steam under pressure (134ºC for 5 minutes - Baumer, Brazil). The routine sterilization quality control monitoring included: physical indicators for each and every cycle, Class I chemical indicators in all packages, Class II (Bowie Dick) daily, and Class V in all surgical boxes and third generation biological indicator daily. In the CSSD storage area, one of the SFB 3.5 was randomly selected (asset number registered), placed in a disinfected plastic box with a lid, and transported to the microbiological laboratory.
A total of nine SFB 3.5 were selected for the study, and 14 cortical screws were removed from each kit: seven screws sizes 14, 16 or 18 (Group 1 - the most frequently used, therefore, those that remain in the box for a shorter time and, consequently are less exposed to biological, chemical and physical agents during handling and multiple processing), and seven screws size 10 or 38 (Group 2 - less used and, therefore, more frequently submitted to the agents mentioned above).
Each SFB 3.5 has four units of cortical screws for each size, totaling 12 screws in Group 1 and eight in Group 2. Screws were randomly selected using the Random App (Mireia Lluch Ortola, Creations Apps). Selected screws were subjected to bacterial culture (n=6 screws/tray, 9 trays), quantitation of contaminating protein (n=6 screws/tray, 9 trays) and Scanning Electron Microscopy (SEM) (n=2 screws/tray, 9 trays).
All screws selected for the analytical tests were visually inspected with the aid of an eight-fold image amplification lens, with an attached light source (LED bench magnifier HL-500 8D, China).(99. Brasil. Ministério da Saúde. Agência Nacional de Vigilância Sanitária. Resolução da Diretoria Colegiada - RDC No 15, de 15 de março de 2012. Dispõe sobre requisitos de boas práticas para o processamento de produtos para saúde e dá outras providências. Brasília (DF): Ministério da Saúde; 2012. [citado 2015 Jul 12]. Disponível em: https://www20.anvisa.gov.br/segurancadopaciente/index.php/legislacao/item/rdc-15-de-15-de-marco-de-2012
https://www20.anvisa.gov.br/segurancadop...
,1010. World Health Organization (WHO). Global guidelines for the prevention of surgical site infection. Geneva: WHO; 2016 [cited 2019 Aug 13]. Available from: https://www.who.int/gpsc/ssi-guidelines/en/
https://www.who.int/gpsc/ssi-guidelines/...
)
Protein was extracted from the screws using a modified alkaline hydrolysis.(1111. Li XZ, Webb JS, Kjelleberg S, Rosche B. Enhanced benzaldehyde tolerance in zymomonas mobilis biofilms and the potential of biofilm applications in fine-chemical production. Appl Environ Microbiol. 2006;72:1639-44.,1212. Chowdhury D, Rahman A, Hu H, Jensen SO, Deva AK, Vickery K. The effect of disinfectant formulation and organic soil on the efficacy of oxidising disinfectants against biofilms. J Hosp Infect. 2019;103(1):e33-41.) Briefly, screws were individually immersed in 2mL (screws number 14, 16 e 18) or 4mL (screws number 38) of ice-cold 2M-Morpholino-ethane sulfonic acid (MES) (20 mM) in 0.9% saline, containing NaOH (30%), and subjected to sonication for 1 hour and vortexing for 2 minutes, prior to incubation at 30°C for 30 minutes followed by immersion in boiling water for 15 minutes. After cooling down, the extracted solution from each screw was transferred to individual plastic tubes and 32% HCl added, and then subjected to centrifugation (13,000 rpm for 5 minutes). A 1mL aliquot of the of extracted sample from each screw was used to quantify protein using 1mL mix of the Pierce® micro-BCA protein Assay test (Thermofisher, Waltham, USA), and incubated and read by spectrophotometry (Digital UV-VIS IL-593-S, Kasuaki), at a wavelength of 562nm, as per manufacturer instructions for use. The protein concentration was calculated (µg/mL), using a standard curve. The test sensitivity was 0.5µg/mL. The protein calculation per screw was: µg/mL X volume of extracted sample.
Individual screws (size 10, 14, 16, 18) were placed in 2.5mL of Tryptic Soy Broth (TSB) or 5.5mL for screw (size 38) and subjected to 10 minutes sonication (USC - 1400A, Unique, São Paulo, Brazil), and vortex for 2 minutes and then incubated at 35°C for up to 28 days.(1313. Tessarolo F, Caola I, Caciagli P, Guarrera GM, Nollo G. Sterility and microbiological assessment of reused single-use cardiac electrophysiology catheters. Infect Control Hosp Epidemiol. 2006;27(12):1385-92.) A 10µL aliquot of the positive cultures were sown on Brain Heart Infusion agar, and bacteria colonies were subjected to Gram staining and cultivated on MacConkey or mannitol salt agar. Bacterial identification and antimicrobial susceptibility testing were performed using the Vitek 2 Compact system (BioMérieux, Marcy-l’Étoile, Carolina do Norte, USA). Antimicrobial susceptibilities were defined according to Clinical and Laboratory Standards Institute break points.(1414. Clinical and Laboratory Standards Institute (CLSI). Performance standards for antimicrobial susceptibility testing. 27th ed. CLSI supplement M100 S27. Wayne PAÇ Clinical and Laboratory Standards Institute, 2017. United States: CLSI; 2017 [cited 2020 May 14]. Available from: https://clsi.org/media/1795/catalog2017_web.pdf
https://clsi.org/media/1795/catalog2017_...
) American Type Culture Collection (ATCC) strains were used as quality controls: Enterococcus faecalis (29212) and Staphylococcus aureus (25923). Antimicrobial sensitivity testing was not performed on Micrococcus sp., Kocuria sp., Gram-positive bacilli and mycobacteria.
The screws were fixed in 2.5% glutaraldehyde in 0.1 M phosphate buffer pH7.2, overnight. Subsequently, the samples were washed in 0.1 M phosphate buffer pH 7.2; dehydrated in increasing concentrations of ethanol; rinsed in hexamethyldisilazane solution (HDMS); mounted on stubs with the aid of carbon painting; and subjected to gold coating (Denton Vacuum - Desk V; Morristown; New Jersey, USA). The whole screw was scanned using SEM (JSM-6610, JOEL, Japan). Screws were considered positive for biofilm if there were aggregated microorganisms immersed in EPS on their surface.(55. Alfa MJ. The “Pandora’s box” dilemma: reprocessing of implantable screws and plates in orthopedic tray sets. Biomed Instrum Technol. 2012;(Suppl):55–9.) A new screw, subjected to one reprocessing, was also assessed by SEM under the same conditions. The Wilcoxon-MannWhitney test was used to analyze the amount of protein on the screws in Groups 1 (most used) and 2 (least used), using the R program. Values of P<0.05 were considered statistically significant.
The Research Ethics Committee from a Universidade Federal de Goiás approved the research (558.585) (CAAE: 26959614.0.0000.5078).
Results
Visual inspection, with the aid of an eight-fold image amplification lens, was performed on all 126 cortical screws. Damage, present as grooves, was detected on 11 (8.7%) screws, predominantly in group 2 (8/11). Two screws (1.6%) from group 2 showed signs of wear. Protein was quantified on 54 screws (27 from each group) and was detected in 52 (96.3%), 26 from each group. In group 1, the average of the amount of protein was 19.85µg (range from 5.03 to 56.3) and, in group 2, it was 26.95µg (range from 6.5 to 65.7). Most of the screws (22/26 and 24/26 from group 1 and group 2, respectively) had contaminating protein > 10µg. There was no statistically significant difference in the amount of protein between the groups (P = 0.07). Bacterial growth was assessed on 27 screws from each group, and was verified in three (5.5%) screws, one from group 1 (most used) and two from group 2 (least used). Micrococcus luteus was isolated from a screw from group 1, and M. luteus (screw A), Kocuria rhizophila and Staphylococcus hominis resistant to rifampin (screw B) from two screws from group 2. Soil and/or grooves were detected on all 18 screws subjected to SEM (Chart 1) (Figure 1), and also on the new screw. Biofilm was detected on eight screws, three from group 1 (most used) and five from group 2 (least used) (Figure 2).
Micrographs showing grooves and soil on orthopedic implants (cortical screws), acquired through loaner system
Micrographs of biofilm on the most used (Group 1) and least used (Group 2) orthopedic implants (cortical screws), acquired through loaner system
Discussion
Patient-ready single-use cortical screws, supplied in loaner orthopaedic kits were found to be contaminated with protein and biofilm, and all were structurally damaged by SEM. However, this damage was also detected by visual inspection in 3/63 and 8/63 screws of groups 1 and 2, respectively. Group 2 screws are likely to remain in the surgical kit for longer and are, therefore, subjected to more opportunities of damage during handling and reprocessing, this may result in “deeper”/”worse” damage in group 2 screws, which was able to be seen visual inspection (with the aid of magnifier lenses). Correlation between corrosion/deterioration on orthopaedic screws and number of reprocessing was reported by McAuley.(1515. McAuley T. Reprocessing of ‘Single-Use’ Orthopaedic Implants. A Study on the Effects of Repeated Reprocessing. In Proceedings of the 17th World Sterilization Congress. Brisbane, Australia, 26–29 October 2016 [cited 2018 July 24]. Available from: https://www.fsraca.org.au/wfhss-2016-17th-world-sterilization-congress/
https://www.fsraca.org.au/wfhss-2016-17t...
) It is worthy highlighting that grooves were also detected on the new screw (reprocessed once only), revealing that surface damage may occur during the manufacturing process, transport of the screw and general handling. Surface damage favors the accumulation of organic matter, increasing the difficulty of reprocessing.
Protein was found on 96.3% (52/54) of the screws, reaching values six times higher (65.7µg) than recommended (٥ µg per side of RMD(1616. United Kingdom Department of Health. Health Technical Memorandum (HTM) 01-01: management and decontamination of surgical instruments (medical devices) used in acute care. Part C: Steam sterilization. UK: United Kingdom Department of Health; 2016 [cited 2018 July 24]. Available from: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/545863/HTM0101PartC.pdf
https://assets.publishing.service.gov.uk...
)or 10µg per RMD), and the average of protein found in each group was 1.9 and 2.6 higher than this acceptable amount. Costa et al.(22. Costa DM, Lopes LK, Vickery K, Watanabe E, Vasconcelos LS, De Paula MC, et al. Reprocessing safety issues associated with complex-design orthopaedic loaned surgical instruments and implants. Injury. 2018;49(11):2005-12.) showed high levels of residual protein on surgical instruments/implants made of stainless steel and subjected to multiple reprocessing in Australia. In Costa et al.(22. Costa DM, Lopes LK, Vickery K, Watanabe E, Vasconcelos LS, De Paula MC, et al. Reprocessing safety issues associated with complex-design orthopaedic loaned surgical instruments and implants. Injury. 2018;49(11):2005-12.) study, all devices, including orthopedic screws, had protein level above the recommended (10µg per PPS), and one screw showed 24µg and 61% of the other surgical instruments had level of protein 10 times or more above the maximum acceptable quantity. Organic matter (carbohydrate, fat), soap and corrosion have also been reported on ready-to-use pedicle screw, used for spinal fusion, by Agarwal et al.(1717. Agarwal A, Schultz C, Agarwal AK, Wang JC, Garfin SF, Anand N. Harboring contaminants in repeatedly reprocessed pedicle screws. Global Spine J. 2019;9:173-8.) The current way screws are presented in the surgical box, on racks that are frequently not removable from the box, make their cleaning, the most important reprocessing step, difficult, as they are numerous (hundreds) and most are very small, increasing the difficulty of supplying sufficient manual friction to ensure adequate cleaning occurs. Most of the manufacturer’s instructions for use in North America do not state how orthopaedic implants, such screws, should be reprocessed.(44. Vickery K, Hu H, Jacombs AS, Bradshaw DA, Deva AK. A review of bacterial biofilms and their role in device-associated infection. Infect Dis Health. 2013;18:61-6. Review.) The high percentage of screws with above the acceptable amount of protein demonstrates this cleaning difficulty and suggests that orthopaedic screws should be presented in an alternate way. Furthermore, as reported by Agaral et al.(1717. Agarwal A, Schultz C, Agarwal AK, Wang JC, Garfin SF, Anand N. Harboring contaminants in repeatedly reprocessed pedicle screws. Global Spine J. 2019;9:173-8.) the recommended reprocessing for pedicle screws is impracticable (19 hours of reprocessing recommended by manufacturer’s versus 1 hour 17 minutes in real-time observation).
Protein on ready-to-use surgical instruments/implants may result in inflammatory responses post-surgery and, in European countries, there is concern for transmission of variant Creutzfeldt–Jakob disease.(1818. World Health Organization (WHO). WHO manual for surveillance of human transmissible spongiform encephalopathies, including variant Creutzfeldt-Jakob disease. Geneva: WHO; 2003 [cited 2016 May 29]. Available from: https://apps.who.int/iris/handle/10665/42656
https://apps.who.int/iris/handle/10665/4...
)
The presence of organic matter decreases the efficacy of sterilization processes. Following processing viable biofilm-forming bacteria were isolated from 3/54 screws and extensive biofilm formation was visually confirmed on 8/18 screws subjected to SEM. This microbial consortium was also reported on loaned screws in previous studies,(22. Costa DM, Lopes LK, Vickery K, Watanabe E, Vasconcelos LS, De Paula MC, et al. Reprocessing safety issues associated with complex-design orthopaedic loaned surgical instruments and implants. Injury. 2018;49(11):2005-12.,1919. Costa DM, Lopes LK, Tipple AF, Johani K, Hu H, Deva AK, et al. Evaluation of stainless steel surgical instruments subjected to multiple use/processing. Infect Dis Health. 2017;23(1):3-9.) and poses a challenge for infection control, as it protects the microorganisms against cleaning, disinfectants, biocides and, as reported by Almatroudi et al.,(2020. Almatroudi A, Gosbell IB, Hu H, Jensen SO, Espedido BA, Tahira S, et al. Staphylococcus aureus dry-surface biofilms are not killed by sodium hypochlorite: implications for infection control. J Hosp Infec. 2016;93(3):263-70.) S. aureus dry surface biofilm can survive autoclaving at 121oC for 30 minutes. The presence of soil aids biofilm formation acting as a conditioning layer for bacteria to attach. Thus, biofilm can form quickly on reprocessed surgical instruments as demonstrated in Lopes et al in vitro study. Biofilm formed on medullary reamers and depth gauges biofilm within 20 cycles of use and reprocessing, including moist heat sterilization (134oC for 3 min and 30 s).(33. Lopes LK, Costa DM, Tipple AF, Watanabe E, Castillo RB, Hu H, et al. Surgical instruments complex design as barrier for cleaning effectiveness, favouring biofilm formation. J Hosp Infect. 2019;103:e53-60.) Biofilm contaminated screws could release viable organisms into the surgical site and result in infection and loss of the implant.
Although classified as single-use, screws are subjected to multiple opportunities of contamination prior to implantation(2121. Costa DM, Vickery K, Tipple AF, Hu H. Providing sterile orthopedic implants: challenges associated with multiple reprocessing of orthopedic surgical trays. Hygiene. 2022;2(1):63-71.) and currently criteria for determining the maximum times a screw should be reprocessed or a way to track the number of times a screw is reprocessed is lacking. There is a trend towards changing to the use of individually packed screws.(1717. Agarwal A, Schultz C, Agarwal AK, Wang JC, Garfin SF, Anand N. Harboring contaminants in repeatedly reprocessed pedicle screws. Global Spine J. 2019;9:173-8.,2222. National Health Scotland (NHS). Decontamination: migration to single-use pre-sterilized individually wrapped small orthopedic implants. Scotland: NHS; 2007 [cited 2019 Oct 10]. Available from: www.sehd.scot.nhs.uk/mels/hdl2007_04.pdf
www.sehd.scot.nhs.uk/mels/hdl2007_04.pdf...
) For example, in Scotland reprocessing of implants is not allowed.(2121. Costa DM, Vickery K, Tipple AF, Hu H. Providing sterile orthopedic implants: challenges associated with multiple reprocessing of orthopedic surgical trays. Hygiene. 2022;2(1):63-71.) According to Litrico et al.,(2323. Litrico S, Recanati G, Gennari A, Maillot C, Saffarini M, Le Huec JC. Single-use instrumentation in posterior lumbar fusion could decrease incidence of surgical site infection: a prospective bi-centric study. Eur J Orthop Surg Traumatol. 2016;26:21-6.) infection rate was lower with presterile single packed screws (2%) compared with the reprocessed implants (6%). On the other hand, this practice also raises concerns about increasing the risk of contamination,(2424. Man WY, Mukherjee A, Feng Lee PY. The economic impact of individually packaged screws. Surgeon. 2014;12(1):35-9.) the length of surgery(2525. Crick B, Chua S, Canty J, McCullough K. Potential for contamination of orthopaedic implants using individually wrapped screws. ANZ J Surg. 2008;78(4):266-8.) and cost.(2525. Crick B, Chua S, Canty J, McCullough K. Potential for contamination of orthopaedic implants using individually wrapped screws. ANZ J Surg. 2008;78(4):266-8.,2626. Suchowersky AM, Hua M, Lorentzos P, Ashton LA. A comparison of risk profile for orthopaedic operations when utilizing individually wrapped screws (IWS) when compared with sterile screw caddies (screw racks). J Orthop Surg (Hong Kong). 2020;28:2309499020944086.)
In Australia and New Zealand,(2727. Australian/New Zeland Standard. AS/NZS 4187:2003Equipment ceaning, disinfecting and sterilizing reusable medical and surgical instruments and equipment, and maintenance of associated environments in health care facilities. Joint Technical Committee HE-023. Australian/New Zealand: Standards Australia International Ltd; 2003 [cited 2019 Oct 10]. Available from: https://www.saiglobal.com/pdftemp/previews/osh/as/as4000/4100/4187.pdf
https://www.saiglobal.com/pdftemp/previe...
) RMD are subjected to high-level disinfection or sterilization before being returned to the loaner company. In Brazil, only cleaning is mandatory.(99. Brasil. Ministério da Saúde. Agência Nacional de Vigilância Sanitária. Resolução da Diretoria Colegiada - RDC No 15, de 15 de março de 2012. Dispõe sobre requisitos de boas práticas para o processamento de produtos para saúde e dá outras providências. Brasília (DF): Ministério da Saúde; 2012. [citado 2015 Jul 12]. Disponível em: https://www20.anvisa.gov.br/segurancadopaciente/index.php/legislacao/item/rdc-15-de-15-de-marco-de-2012
https://www20.anvisa.gov.br/segurancadop...
) Cleaning reduces the microbial load and other organic and inorganic matter, however the remaining contamination favours biofilm formation until the surgical box is reprocessed/used at another healthcare service. Presence of blood has been reported on loaned surgical boxes upon delivery at the healthcare facilities in USA(2828. Winthrop TG, Sion BA, Gaines C. Loaner instrumentation: Processing the unknown. AORN J. 2007;85(3):566-73.,2929. Huter-Kunish GG. Processing loaner instruments in an ambulatory surgery center. AORN J. 2009;89(5):861-70.) and Brazil,(22. Costa DM, Lopes LK, Vickery K, Watanabe E, Vasconcelos LS, De Paula MC, et al. Reprocessing safety issues associated with complex-design orthopaedic loaned surgical instruments and implants. Injury. 2018;49(11):2005-12.) revealling the occupational risk for the loaner-company workers, which frequently do not have specific biological risk training.(22. Costa DM, Lopes LK, Vickery K, Watanabe E, Vasconcelos LS, De Paula MC, et al. Reprocessing safety issues associated with complex-design orthopaedic loaned surgical instruments and implants. Injury. 2018;49(11):2005-12.) Even though quality indicators regarding structure and work process for the management and reprocessing of loaned RMD and implants, such as screws, tent to be higher standard in high-income country than in middle or low-income country, failures are present in both countries category, highlighting the need to multifaceted loaner system key challenges need to be faced worldwide.(3030. Tipple AF, Costa DM, Lopes LK, Veloso TR, Pereira LA, Hu H, et al. Reprocessing of loaned surgical instruments/implants in Australia and Brazil: a survey of those at the coalface. Infect Dis Health. 2022;27(1):23-30.)
Conclusion
Patient-ready cortical screws were found to be contaminated by viable bacteria, biofilm, and have grooves. Screws frequently remain in surgical trays for multiple reprocessing, thus they are repeatedly exposed to contamination and possible damage. These findings point to the need to discuss and review the way these single-use implants are currently made available for surgery.
Acknowledgements
The National Council of Science and Technology – Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq; research grant: 484578/2013-8), Coordination for the Improvement of Higher Education Personnel – Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES; post-doctorage’s scholarship for Dayane de Melo Costa; research grant: 88882.306482/2018-01).
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30Tipple AF, Costa DM, Lopes LK, Veloso TR, Pereira LA, Hu H, et al. Reprocessing of loaned surgical instruments/implants in Australia and Brazil: a survey of those at the coalface. Infect Dis Health. 2022;27(1):23-30.
Edited by
Publication Dates
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Publication in this collection
06 Feb 2023 -
Date of issue
2023
History
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Received
30 Mar 2021 -
Accepted
29 Aug 2022