Evaluation of measures to decrease intra-operative bacterial contamination in orthopaedic implant surgery

From basic research to clinical practice: The impact of laminar airflow filters on surgical site infection in vascular surgery

BACKGROUND

Laminar airflow filters have been suggested as a potential preventive factor for surgical site infections, given their ability to reduce the airborne microbiological load. However, their role is still unclear, and evidence regarding vascular surgery patients is scarce. Our aim was to assess the impact of laminar-airflow filters on surgical site infections.

METHODS

This single-centre retrospective cohort study was conducted with vascular surgery patients who underwent arterial vascular intervention through a groin incision between July 2018 and July 2019 (turbulent airflow cohort) and July 2020 and July 2021 (laminar airflow cohort). Data were prospectively collected from electronic medical files. We estimated the cumulative incidence of surgical site infections and its 95% confident interval (95%CI). A propensity score matching analysis was performed.

RESULTS

We included 200 patients, 78 in the turbulent airflow cohort and 122 in the laminar airflow cohort. The cumulative incidence was 15.4% (12/78; 95%CI: 9.0-25.0%) in the turbulent-airflow cohort and 14.8% (18/122; 95%CI: 9.5 -22.1%) in the laminar-airflow cohort (p-value: 1.00). The propensity score matching yielded a cumulative incidence of surgical site infection of 13.9% (10/72) with turbulent airflow and 12.5% (9/72) with laminar airflow (p-value: 1.00). Risk factors associated with infection were chronic kidney disease (OR 2.70; 95%CI: 1.14-6.21) and a greater body mass index (OR 1.47; 95%CI: 1.01-2.14).

CONCLUSION

Laminar airflow filters were associated with a non-significant reduction of surgical site infections. Further research is needed to determine its usefulness and cost-effectiveness. Surgical site infection incidence was associated with chronic kidney disease and a greater body mass index. Hence, efforts should be made to optimize the body mass index before surgery and prevent chronic kidney disease in patients with known arterial disease.

Staphylococcus aureus surface attachment selectively influences tolerance against charged antibiotics

The threat of infection during implant placement surgery remains a considerable burden for millions of patients worldwide. To combat this threat, clinicians employ a range of anti-infective strategies and practices. One of the most common interventions is the use of prophylactic antibiotic treatment during implant placement surgery. However, these practices can be detrimental by promoting the resilience of biofilm-forming bacteria and enabling them to persist throughout treatment and re-emerge later, causing a life-threatening infection. Thus, it is of the utmost importance to elucidate the events occurring during the initial stages of bacterial surface attachment and determine whether any biological processes may be targeted to improve surgical outcomes. Using gene expression analysis, we identified a cellular mechanism of S. aureus which modifies its cell surface charge following attachment to a medical grade titanium surface. We determined the upregulation of two systems involved in the d-alanylation of teichoic acids and the lysylation of phosphatidylglycerol. We supported these molecular findings by utilizing synchrotron-sourced attenuated total reflection Fourier-transform infrared microspectroscopy to analyze the biomolecular properties of the S. aureus cell surface following attachment. As a direct consequence, S. aureus quickly becomes substantially more tolerant to the positively charged vancomycin, but not the negatively charged cefazolin. The present study can assist clinicians in rationally selecting the most potent antibiotic in prophylaxis treatments. Furthermore, it highlights a cellular process that could potentially be targeted by novel technologies and strategies to improve the outcome of antibiotic prophylaxis during implant placement surgery. STATEMENT OF SIGNIFICANCE: The antibiotic tolerance of bacteria in biofilm is a well-established phenomenon. However, the physiological adaptations employed by Staphylococcus aureus to increase its antibiotic tolerance during the early stages of surface attachment are poorly understood. Using multiple techniques, including gene expression analysis and synchrotron-sourced Fourier-transform infrared microspectroscopy, we generated insights into the physiological response of S. aureus following attachment to a medical grade titanium surface. We showed that this phenotypic transition enables S. aureus to better tolerate the positively charged vancomycin, but not the negatively charged cefazolin. These findings shed light on the antibiotic tolerance mechanisms employed by S. aureus to survive prophylactically administered antibiotics and can help clinicians to protect patients from infections.

Customized biofilm device for antibiofilm and antibacterial screening of newly developed nanostructured silver and zinc coatings

BACKGROUND

Bacterial colonisation on implantable device surfaces is estimated to cause more than half of healthcare-associated infections. The application of inorganic coatings onto implantable devices limits/prevents microbial contaminations. However, reliable and high-throughput deposition technologies and experimental trials of metal coatings for biomedical applications are missing. Here, we propose the combination of the Ionized Jet Deposition (IJD) technology for metal-coating application, with the Calgary Biofilm Device (CBD) for high-throughput antibacterial and antibiofilm screening, to develop and screen novel metal-based coatings.

RESULTS

The films are composed of nanosized spherical aggregates of metallic silver or zinc oxide with a homogeneous and highly rough surface topography. The antibacterial and antibiofilm activity of the coatings is related with the Gram staining, being Ag and Zn coatings more effective against gram-negative and gram-positive bacteria, respectively. The antibacterial/antibiofilm effect is proportional to the amount of metal deposited that influences the amount of metal ions released. The roughness also impacts the activity, mostly for Zn coatings. Antibiofilm properties are stronger on biofilms developing on the coating than on biofilms formed on uncoated substrates. This suggests a higher antibiofilm effect arising from the direct contact bacteria-coating than that associated with the metal ions release. Proof-of-concept of application to titanium alloys, representative of orthopaedic prostheses, confirmed the antibiofilm results, validating the approach. In addition, MTT tests show that the coatings are non-cytotoxic and ICP demonstrates that they have suitable release duration (> 7 days), suggesting the applicability of these new generation metal-based coatings for the functionalization of biomedical devices.

CONCLUSIONS

The combination of the Calgary Biofilm Device with the Ionized Jet Deposition technology proved to be an innovative and powerful tool that allows to monitor both the metal ions release and the surface topography of the films, which makes it suitable for the study of the antibacterial and antibiofilm activity of nanostructured materials. The results obtained with the CBD were validated with coatings on titanium alloys and extended by also considering the anti-adhesion properties and biocompatibility. In view of upcoming application in orthopaedics, these evaluations would be useful for the development of materials with pleiotropic antimicrobial mechanisms.

Operating room ventilation systems: Recovery Degree, Cleanliness Recovery Rate and Air Change Effectiveness in an ultra-clean area

BACKGROUND

Entrainment test methods are described in most European standards and guidelines to determine the protected area for Ultra-Clean Ventilation (UCV) systems. New UCV systems, such as temperature-controlled airflow (TcAF) and controlled-dilution ventilation (cDV) claim the whole Operating Room (OR) to be ultra-clean. Current test standards are not developed for assessing ventilation effectiveness outside the standard protected area.

AIM

To assess and compare the ventilation effectiveness of four types of OR ventilation systems in the ultra-clean area by using a uniform test grid.

METHODS

In this study the ventilation effectiveness (VE) of four ventilation systems is evaluated for three different ultra-clean (protected) areas; standard protected area (A), area outside standard protected area (B) and large protected area (AB). The VE is defined as the recovery degree (RD), cleanliness recovery rate (CRR) and air change effectiveness (ACE).

FINDINGS

RD, CRR and ACE were significantly higher for the Uni Directional Air Flow (UDAF) system when compared to the other systems in area A. In area B, UDAF and cDV were comparable regarding RD and CRR and UDAF and Conventional Ventilation (CV) were comparable regarding ACE. In area AB the UDAF and cDV were comparable regarding CRR and ACE but are significantly different in RD.

CONCLUSION

In area A the ventilation effectiveness of the UDAF ventilation system is outperforming other ventilation systems. In area B, cDV is performing the best followed by UDAF, TcAF and CV. In area AB, UDAF is performing the best followed by cDV, TcAF and CV.

Bacterial contamination of bone allografts in the tissue banks: a systematic review and meta-analysis

BACKGROUND

Bone allografts are harvested and transplanted under sterile conditions. However, the risk of bacterial contamination of grafts during these processes is a health concern. Bioburden testing and bacterial contamination detection are conducted to ensure allograft sterility.

AIM

The present study aimed to determine the incidence of bacterial contamination in bone allografts based on different classifications.

METHODS

PROSPERO registration number was received for the study. Systematic searches were conducted in PubMed and EMBASE databases with relevant keywords from January 2000 to March 2021. After choosing related studies according to the PRISMA flow diagram, Stata software was used for data analysis. We considered I² ˃ 50% as heterogeneity between studies.

FINDINGS

The overall incidence of bacterial contamination was 12.6% (95% CI 0.100, 0.152) among 19,805 bone allografts of 17 studies. The bacterial contamination rate among bone allografts was 10.8% before 2010 and 14.7% in 2010-March 2021. The contamination frequency in Asia, Europe, and Australia was 11.5%, 14.3%, and 5.2%, respectively. Bone contamination rates were higher in cadaver donors (19.9%), retrieval time sampling (13.5%), and swab samples (13.2%) compared to those in living donors (7.5%), implantation time sampling (6.9%), and bone fragments cultures (6.3%). Bacterial contamination was recovered 24.4%, 19.7%, 13.2%, and 21% from tibia, fibula, femoral, and other bones, respectively. Staphylococcus spp. was the predominant isolated bacteria from bones (63.2% of all isolated genera), followed by Propionibacterium spp. (10.6%).

CONCLUSION

The high contamination of bone allografts is a health concern, indicating the need for more health monitoring and improvement of standards.

In Situ Coatings of Silver Nanoparticles for Biofilm Treatment in Implant-Retention Surgeries: Antimicrobial Activities in Monoculture and Coculture

Bacterial biofilms are indicated in most medical device-associated infections. Treating these biofilms is challenging yet critically important for applications such as in device-retention surgeries, which can have reinfection rates of up to 80%. This in vitro study centered around our new method of treating biofilm and preventing reinfection. Ionic silver (Ag, in the form of silver nitrate) combined with dopamine and a biofilm-lysing enzyme (α-amylase) were applied to model 4-day-old Staphylococcus aureus biofilms on titanium substrates to degrade the extracellular matrix of the biofilm and kill the biofilm bacteria. In this process, the oxidative self-polymerization of dopamine converted Ag ions into Ag nanoparticles that, together with the resultant self-adhering polydopamine (PDA), formed coatings that strongly bound to the treated substrates. Surprisingly, although these Ag/PDA coatings significantly reduced S. aureus growth in standard bacterial monoculture, they showed much lower antimicrobial activity in coculture of the bacteria and osteoblastic MC3T3-E1 cells in which the bacteria were also found attached to the osteoblasts. This S. aureus- osteoblast interaction was also linked to bacterial survival against gentamicin treatment observed in coculture. Our study thus provided clear evidence suggesting that bacteria's interactions with tissue cells surrounding implants may significantly contribute to their resistance to antimicrobial treatment.

Evidence-based uncertainty: do implant-related properties of titanium reduce the susceptibility to perioperative infections in clinical fracture management? A systematic review

Background

Implant-associated infections (IAI) remain a challenging complication in osteosynthesis. There is no consensus or clear evidence whether titanium offers a relevant clinical benefit over stainless steel.

Purpose

In this systematic review, we sought to determine whether the implant properties of titanium reduce the susceptibility to IAI compared to stainless steel in fracture management.

Methods

A systematic literature search in German and English was performed using specific search terms and limits. Studies published between 1995 and 1st June 2020 in the Cochrane library, MEDLINE and Web of Science databases were included. Only clinical studies comparing titanium and stainless steel implants regarding the susceptibility to infections were selected for detailed review.

Results

Five studies out of 384 papers were identified and reviewed. From the studies meeting inclusion criteria one study was a systematic review, two studies were randomized controlled studies (RCT) and two studies were of retrospective comparative nature of level IV evidence.

Conclusion

Our results show that currently, no proven advantage for titanium implants in respect to IAI can be seen in contemporary literature. Implants preserving periosteal blood-flow and minimising soft-tissue trauma show statistically significant benefits in reducing the incidence of IAI. Clinical studies providing reliable evidence regarding the influence of titanium implants on IAI and investigating the susceptibility of titanium to infection are necessary

Implant contamination as a cause of surgical site infection in spinal surgery: are single-use implants a reasonable solution? - a systematic review

Background

In spine surgery, surgical site infection (SSI) is one of the main perioperative complications and is associated with a higher patient morbidity and longer patient hospitalization. Most factors associated with SSI are connected with asepsis during the surgical procedure and thus with contamination of implants and instruments used which can be caused by pre- and intraoperative factors. In this systematic review we evaluate the current literature on these causes and discuss possible solutions to avoid implant and instrument contamination.

Methods

A systematic literature search of PubMed addressing implant, instrument and tray contamination in orthopaedic and spinal surgery from 2001 to 2019 was conducted following the PRISMA guidelines. All studies regarding implant and instrument contamination in orthopaedic surgery published in English language were included.

Results

Thirty-five studies were eligible for inclusion and were divided into pre- and intraoperative causes for implant and instrument contamination. Multiple studies showed that reprocessing of medical devices for surgery may be insufficient and lead to surgical site contamination. Regarding intraoperative causes, contamination of gloves and gowns as well as contamination via air are the most striking factors contributing to microbial contamination.

Conclusions

Our systematic literature review shows that multiple factors can lead to instrument or implant contamination. Intraoperative causes of contamination can be avoided by implementing behavior such as changing gloves right before handling an implant and reducing the instruments’ intraoperative exposure to air. In avoidance of preoperative contamination, there still is a lack of convincing evidence for the use of single-use implants in orthopaedic surgery.

Prevention of Prosthetic Joint Infection: From Traditional Approaches towards Quality Improvement and Data Mining

A projected increased use of total joint arthroplasties will naturally result in a related increase in the number of prosthetic joint infections (PJIs). Suppression of the local peri-implant immune response counters efforts to eradicate bacteria, allowing the formation of biofilms and compromising preventive measures taken in the operating room. For these reasons, the prevention of PJI should focus concurrently on the following targets: (i) identifying at-risk patients; (ii) reducing “bacterial load” perioperatively; (iii) creating an antibacterial/antibiofilm environment at the site of surgery; and (iv) stimulating the local immune response. Despite considerable recent progress made in experimental and clinical research, a large discrepancy persists between proposed and clinically implemented preventative strategies. The ultimate anti-infective strategy lies in an optimal combination of all preventative approaches into a single “clinical pack”, applied rigorously in all settings involving prosthetic joint implantation. In addition, “anti-infective” implants might be a choice in patients who have an increased risk for PJI. However, further progress in the prevention of PJI is not imaginable without a close commitment to using quality improvement tools in combination with continual data mining, reflecting the efficacy of the preventative strategy in a particular clinical setting.

Rates of periprosthetic infection and surgical revision in Beijing (China) between 2014 and 2016: a retrospective multicenter cross-sectional study

Background

Periprosthetic joint infection (PJI) is a rare but devastating complication after total joint arthroplasty. There is a paucity of data on the incidence and prevalence of periprosthetic infection in mainland China. This study aimed to analyze the rates of surgical revision after arthroplasty due to PJI and the procedures followed in Beijing, China.

Methods

The study involved a retrospective multicenter cross-sectional survey of patients undergoing revisions for periprosthetic infection after hip/knee arthroplasty at nine hospitals in Beijing from 2014 to 2016. Age, gender, body mass index, primary diagnosis, comorbidity, primary surgery, treatment methods, and post-revision complications were analyzed.

Results

A total of 38,319 hip/knee arthroplasties and 366 (0.96%) revisions for PJI were identified. Of these, 161 (161/14,110; 1.14%) revisions involved hip arthroplasty, whereas 205 (205/24,209; 0.85%) revisions were due to knee arthroplasty. Procedures for revisions of infected hip included 7 (4.3%) cases of open debridement and prosthesis retention, 32 (19.9%) cases of one-stage exchange, 121 (75.2%) cases of two-stage exchange, and 1 (0.007%) case of hip dissection. As for the infected knee, the procedures included 45 (22.0%) cases of open debridement and prosthesis retention, 13 (6.3%) cases of one-stage exchange, 143 (69.8%) cases of two-stage exchange, and 4 (0.02%) cases of knee fusion.

Conclusions

The study found the rates of revision due to PJI to be low. Nonetheless, the incidence of PJI in mainland China could be higher and calls for more elaborate studies in geographically and socioeconomically diverse health institutions.

Laminar flow does not affect risk of prosthetic joint infection after primary total knee replacement in Asian patients

BACKGROUND

The role of laminar flow (LAF) is contradictory with several studies failing to replicate risk reduction. The 2016 World Health Organization guidelines identified this lack of good comparative studies.

AIM

To analyse the use of LAF and the incidence of prosthetic joint infections (PJIs) in Asian patients undergoing total knee replacement (TKR).

METHODS

Patients who underwent standard cemented posterior-stabilized TKR from 2004 to 2014 were reviewed from a prospectively collected single-surgeon database. Revision, traumatic and/or inflammatory cases were excluded. The type of airflow used was identified. The technique and surgical protocol for all procedures were similar. Tourniquets and inserted drains were routinely used. Patellar resurfacing was not performed. Patients were followed up at the outpatient clinics at regular intervals up to two years. At each visit, the patient was assessed for the occurrence of PJI.

FINDINGS

Of the 1028 procedures, 453 (44.1%) were performed in an LAF operating theatre (OT) whereas 575 (55.9%) were performed in a non-LAF OT. There were no significant differences between the two groups in terms of age, gender, or side of procedure. The overall incidence of PJI was 0.6% (N = 6). Three (50%) occurred in an LAF OT whereas three (50%) occurred in a non-LAF OT. This was not statistically significant.

CONCLUSION

Laminar flow systems are costly to procure and maintain. With modern aseptic techniques, patient optimization, and use of prophylactic antibiotics, laminar flow does not appear to further reduce risk of PJI in Asian patients after TKR.

Impact of salivary contamination during placement of implants with simultaneous bony augmentation in iliac bone in sheep

Our aim was to investigate the possible impact of contamination with saliva on osseointegration during placement of implants with simultaneous bone augmentation. Six hemispheric shape bone defects (8mm in diameter×4mm deep) were prepared in each iliac bone of six sheep. A dental implant (2.9mm in diameter×10mm long) was placed in the centre of each defect, and then pairs of defects were filled with one of the following bone augmentation materials: autogenous bone, autogenous bone plus bovine bone, or resorbable biphasic ceramic bone substitute. One site in each augmentation group was impregnated with saliva (contaminated group), while the other was not (non-contaminated group). Bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO) within implant threads were measured after a healing period of five weeks, both in respect of the implant inserted in the augmented bone and in that inserted in the residual bone. Overall results showed that there was a significant difference between the contaminated and non-contaminated group for BIC in the augmented implant (p=0.028), while there were no significant differences in the implant in residual bone (p=0.722). For BAFO, there were no significant differences between the contaminated and non-contaminated groups among the different augmentation materials. The results showed that contamination with saliva during placement of an implant with simultaneous bone augmentation had a serious deleterious effect on osseointegration of the aspect of the implant within the augmented defect. Contamination with saliva during placement of an implant with simultaneous bone augmentation should therefore be avoided.

Microbial colonization of subscapularis tagging sutures in shoulder arthroplasty: a prospective, controlled study

BACKGROUND

Reducing intraoperative wound contamination is a critical preventive strategy for reducing the risk of prosthetic joint infection in shoulder arthroplasty. The aim of this study was to investigate the potential microbial colonization of subscapularis tagging sutures during shoulder arthroplasty.

METHODS

In this prospective study, 50 consecutive patients undergoing primary shoulder arthroplasty (anatomic or reverse) were enrolled. Patients with revision shoulder arthroplasty and proximal humeral fractures were excluded. Nonabsorbable, braided tagging sutures were placed through the subscapularis tendon prior to tenotomy. A similar nonabsorbable, braided suture (control) was placed in a sterile container on the back table, open to the operating room environment. Subscapularis tagging sutures (experimental specimens) and control sutures were collected prior to subscapularis tenotomy repair and submitted for aerobic and anaerobic cultures. Cultures were held for 21 days to account for extended growth of slow-growing bacteria.

RESULTS

A total of 12 of 50 experimental and 16 of 50 control sutures had positive cultures. Staphylococcus epidermidis and Cutibacterium acnes were the 2 most commonly isolated organisms. Active tobacco use (P = .038) and procedure length (P = .03) were significantly associated with positive cultures. No significant association between positive subscapularis tagging suture cultures and positive control cultures was found (P = .551). Patient age, sex, body mass index, and significant medical comorbidities were not significantly associated with positive cultures.

DISCUSSION

Subscapularis tagging sutures are a potential source of microbial contaminant in shoulder arthroplasty, and we recommend exchanging the tagging suture with a suture opened immediately prior to subscapularis repair.

Is surface modification effective to prevent periprosthetic joint infection? A systematic review of preclinical and clinical studies

BACKGROUND

With increasing recognition of the importance of biofilm formation in the pathogenesis of periprosthetic joint infection (PJI), a push towards finding solutions to prevent PJI via surface modification of prostheses is occurring. Unlike the promising in vitro antimicrobial effects of these surface modifications, the preclinical and clinical prophylactic effects vary and are debated. Therefore, we performed this systematic review to answer: (1) what kinds of methods of surface modification are used in preclinical and clinical studies to prevent PJI, (2) whether these modifications are effective to prevent PJI.

METHODS

Electronic searches were performed using PubMed, Embase and the Cochrane library databases up to and including December 2017 with predetermined criteria: (1) in vivo studies with (2) surface modification for prophylactic effects against infection. Both animal studies and clinical trials were included. Data were extracted and presented systematically.

RESULTS

Overall, 21 studies were included. Among these, fourteen were carried out in animal models and seven were clinical studies. In the animal studies, six used antibiotics and six silver modifications, while copper and Cationic Steroidal Antimicrobial-13 were each used for one study. In the seven clinical studies targeting patients with high infection risk, five of them focused on silver-coated prostheses and the remaining two studied iodine-coated implants. In all of the animal studies, when compared with the control group, the surface modified groups had a lower infection risk (RR ranging from 0 to 0.71). Clinical studies using silver-coated prostheses also demonstrated a lower infection risk (RR ranging from 0.24 to 0.70), while iodine-coated implants showed a 0% and 5% incidence of PJI in the two case series included.

DISCUSSION

The results from the publications included in this review indicate that surface modification, especially antibiotic and silver modifications, are helpful preventing PJI in both preclinical animal models and in clinical trials.

LEVEL OF EVIDENCE

III, systematic review of level III retrospective comparative studies and level IV case series and animal experiments.

Comparison of operating room air distribution systems using the environmental quality indicator method of dynamic simulated surgical procedures

BACKGROUND

Ensuring aseptic airborne environments for sterile fields and back instrument tables in operating rooms (ORs) is crucial to reducing microbial and particle contamination during surgery. Configurations of in-ceiling air delivery mechanisms impact the effectiveness of the system at eliminating contamination in critical zones.

METHODS

The environmental quality indicator method was used to assess airborne environments in ORs equipped with a single large diffuser (SLD), a multidiffuser array (MDA), or a 4-way throw diffuser during dynamic, simulated surgical procedures. Environmental quality indicators measured included particles, microbes, carbon dioxide, velocity, humidity, and temperature at 26 air changes per hour.

RESULTS

SLD ORs performed better than MDA ORs and 4-way throw diffuser ORs at removing microbes and carbon dioxide from the sterile field (P < .05). SLD ORs had higher velocity and lower temperature over the sterile field than the other 2 ORs (P < .05). MDA ORs had lower total particle counts than the other ORs (P < .05). The sterile fields in all ORs were cleaner than the respective back instrument tables (P < .05).

CONCLUSIONS

Air delivery systems that eliminate blockages to uniform airflow directly over sterile zones, such as boom mounts and access panels, and deliver unidirectional, downward flow of clean filtered air provided a cleaner airborne environment within the sterile field. Expansion of air delivery systems to include areas outside the sterile field, where other surgical aides reside, may further reduce contamination within critical zones.

The effectiveness of ultra-clean air operating theatres in the prevention of deep infection in joint arthroplasty surgery

Deep infection was identified as a serious complication in the earliest days of total hip arthroplasty. It was identified that airborne contamination in conventional operating theatres was the major contributing factor. As progress was made in improving the engineering of operating theatres, airborne contamination was reduced. Detailed studies were carried out relating airborne contamination to deep infection rates.

In a trial conducted by the United Kingdom Medical Research Council (MRC), it was found that the use of ultra-clean air (UCA) operating theatres was associated with a significant reduction in deep infection rates. Deep infection rates were further reduced by the use of a body exhaust system. The MRC trial also included a detailed microbiology study, which confirmed the relationship between airborne contamination and deep infection rates.

Recent observational evidence from joint registries has shown that in contemporary practice, infection rates remain a problem, and may be getting worse. Registry observations have also called into question the value of “laminar flow” operating theatres.

Observational evidence from joint registries provides very limited evidence on the efficacy of UCA operating theatres. Although there have been some changes in surgical practice in recent years, the conclusions of the MRC trial remain valid, and the use of UCA is essential in preventing deep infection.

There is evidence that if UCA operating theatres are not used correctly, they may have poor microbiological performance. Current UCA operating theatres have limitations, and further research is required to update them and improve their microbiological performance in contemporary practice.

Cite this article: Bone Joint J 2018;100-B:1264–9.

Polycrystalline Diamond Coating of Additively Manufactured Titanium for Biomedical Applications

Additive manufacturing using selective laser melted titanium (SLM-Ti) is used to create bespoke items across many diverse fields such as medicine, defense, and aerospace. Despite great progress in orthopedic implant applications, such as for "just in time" implants, significant challenges remain with regards to material osseointegration and the susceptibility to bacterial colonization on the implant. Here, we show that polycrystalline diamond coatings on these titanium samples can enhance biological scaffold interaction improving medical implant applicability. The highly conformable coating exhibited excellent bonding to the substrate. Relative to uncoated SLM-Ti, the diamond coated samples showed enhanced mammalian cell growth, enriched apatite deposition, and reduced microbial S. aureus activity. These results open new opportunities for novel coatings on SLM-Ti devices in general and especially show promise for improved biomedical implants.

Temperature-controlled airflow ventilation in operating rooms compared with laminar airflow and turbulent mixed airflow

AIM

To evaluate three types of ventilation systems for operating rooms with respect to air cleanliness [in colony-forming units (cfu/m³)], energy consumption and comfort of working environment (noise and draught) as reported by surgical team members.

METHODS

Two commonly used ventilation systems, vertical laminar airflow (LAF) and turbulent mixed airflow (TMA), were compared with a newly developed ventilation technique, temperature-controlled airflow (T_cAF). The cfu concentrations were measured at three locations in an operating room during 45 orthopaedic procedures: close to the wound (<40cm), at the instrument table and peripherally in the room. The operating team evaluated the comfort of the working environment by answering a questionnaire.

FINDINGS

LAF and T_cAF, but not TMA, resulted in less than 10cfu/m³ at all measurement locations in the room during surgery. Median values of cfu/m³ close to the wound (250 samples) were 0 for LAF, 1 for T_cAF and 10 for TMA. Peripherally in the room, the cfu concentrations were lowest for T_cAF. The cfu concentrations did not scale proportionally with airflow rates. Compared with LAF, the power consumption of T_cAF was 28% lower and there was significantly less disturbance from noise and draught.

CONCLUSION

T_cAF and LAF remove bacteria more efficiently from the air than TMA, especially close to the wound and at the instrument table. Like LAF, the new T_cAF ventilation system maintained very low levels of cfu in the air, but T_cAF used substantially less energy and provided a more comfortable working environment than LAF. This enables energy savings with preserved air quality.

Effects of Bacterial Contamination on Dental Implants During Surgery: A Systematic Review

INTRODUCTION

Contamination during surgery negatively influences the prognosis of orthopaedic implants; however, it has not been proven whether contamination influences the success of dental implant treatment. The aim of the systematic review was to investigate if there exists evidence in the literature whether contamination of dental implants during surgery affects osseointegration and clinical success.

MATERIALS AND METHODS

Four data bases were used for the literature search. Primary studies and reviews regarding both clinical and preclinical research were eligible. Rating of the summarized quality of the evidence was performed.

RESULTS

Five preclinical studies were included. Because of the estimated high risk of bias in all included studies and extensive differences in study design between the included studies, meta-analysis was not performed and no reliable aggregated data could be extracted.

CONCLUSIONS

It is suggested that the scientific evidence with regard to the current topic is insufficient. Further controlled studies are warranted.

Factors contributing to airborne particle dispersal in the operating room

Background

Surgical-site infections due to intraoperative contamination are chiefly ascribable to airborne particles carrying microorganisms. The purpose of this study is to identify the actions that increase the number of airborne particles in the operating room.

Methods

Two surgeons and two surgical nurses performed three patterns of physical movements to mimic intraoperative actions, such as preparing the instrument table, gowning and donning/doffing gloves, and preparing for total knee arthroplasty. The generation and behavior of airborne particles were filmed using a fine particle visualization system, and the number of airborne particles in 2.83 m³ of air was counted using a laser particle counter. Each action was repeated five times, and the particle measurements were evaluated through one-way analysis of variance multiple comparison tests followed by Tukey–Kramer and Bonferroni–Dunn multiple comparison tests for post hoc analysis. Statistical significance was defined as a P value ≤ .01.

Results

A large number of airborne particles were observed while unfolding the surgical gown, removing gloves, and putting the arms through the sleeves of the gown. Although numerous airborne particles were observed while applying the stockinet and putting on large drapes for preparation of total knee arthroplasty, fewer particles (0.3–2.0 μm in size) were detected at the level of the operating table under laminar airflow compared to actions performed in a non-ventilated preoperative room (P < .01).

Conclusions

The results of this study suggest that surgical staff should avoid unnecessary actions that produce a large number of airborne particles near a sterile area and that laminar airflow has the potential to reduce the incidence of bacterial contamination.

Effect of laminar airflow ventilation on surgical site infections: a systematic review and meta-analysis

BACKGROUND

The role of the operating room's ventilation system in the prevention of surgical site infections (SSIs) is widely discussed, and existing guidelines do not reflect current evidence. In this context, laminar airflow ventilation was compared with conventional ventilation to assess their effectiveness in reducing the risk of SSIs.

METHODS

We searched MEDLINE, Embase, Cochrane Central Register of Controlled Trials, and WHO regional medical databases from Jan 1, 1990, to Jan 31, 2014. We updated the search for MEDLINE for the period between Feb 1, 2014, and May 25, 2016. We included studies most relevant to our predefined question: is the use of laminar airflow in the operating room associated with the reduction of overall or deep SSI as outcomes in patients of any age undergoing surgical operations? We excluded studies not relevant to the study question, studies not in the selected languages, studies published before Jan 1, 1990, or after May 25, 2016, meeting or conference abstracts, and studies of which the full text was not available. Data were extracted by two independent investigators, with disagreements resolved through further discussion. Authors were contacted if the full-text article was not available, or if important data or information on the paper's content was absent. Studies were assessed for publication bias. Grading of recommendations assessment, development, and evaluation was used to assess the quality of the identified evidence. Meta-analyses were done with RevMan (version 5.3).

FINDINGS

We identified 1947 records of which 12 observational studies were comparing laminar airflow ventilation with conventional turbulent ventilation in orthopaedic, abdominal, and vascular surgery. The meta-analysis of eight cohort studies showed no difference in risk for deep SSIs following total hip arthroplasty (330 146 procedures, odds ratio [OR] 1·29, 95% CI 0·98-1·71; p=0·07, I²=83%). For total knee arthroplasty, the meta-analysis of six cohort studies showed no difference in risk for deep SSIs (134 368 procedures, OR 1·08, 95% CI 0·77-1·52; p=0·65, I²=71%). For abdominal and open vascular surgery, the meta-analysis of three cohort studies found no difference in risk for overall SSIs (63 472 procedures, OR 0·75, 95% CI 0·43-1·33; p=0·33, I²=95%).

INTERPRETATION

The available evidence shows no benefit for laminar airflow compared with conventional turbulent ventilation of the operating room in reducing the risk of SSIs in total hip and knee arthroplasties, and abdominal surgery. Decision makers, medical and administrative, should not regard laminar airflow as a preventive measure to reduce the risk of SSIs. Consequently, this equipment should not be installed in new operating rooms.

FUNDING

None.

The Neurostimulation Appropriateness Consensus Committee (NACC) Recommendations for Infection Prevention and Management

INTRODUCTION

The use of neurostimulation for pain has been an established therapy for many decades and is a major tool in the arsenal to treat neuropathic pain syndromes. Level I evidence has recently been presented to substantiate the therapy, but this is balanced against the risk of complications of an interventional technique.

METHODS

The Neurostimulation Appropriateness Consensus Committee (NACC) of the International Neuromodulation Society convened an international panel of well published and diverse physicians to examine the best practices for infection mitigation and management in patients undergoing neurostimulation. The NACC recommendations are based on evidence scoring and peer-reviewed literature. Where evidence is lacking the panel added expert opinion to establish recommendations.

RESULTS

The NACC has made recommendations to improve care by reducing infection and managing this complication when it occurs. These evidence-based recommendations should be considered best practices in the clinical implantation of neurostimulation devices.

CONCLUSION

Adhering to established standards can improve patient care and reduce the morbidity and mortality of infectious complications in patients receiving neurostimulation.

Association of Airborne Microorganisms in the Operating Room With Implant Infections: A Randomized Controlled Trial

OBJECTIVE

To evaluate the association of airborne colony-forming units (CFU) at incision sites during implantation of prostheses with the incidence of either incisional or prosthesis-related surgical site infections.

DESIGN

Randomized, controlled trial.

SETTING

Primary, public institution.

PATIENTS

Three hundred patients undergoing total hip arthroplasty, instrumented spinal procedures, or vascular bypass graft implantation.

METHODS

Patients were randomly assigned in a 1:1 ratio to either the intervention group or the control group. A novel device (Air Barrier System), previously shown to reduce airborne CFU at incision sites, was utilized in the intervention group. Procedures assigned to the control group were performed without the device, under routine operating room atmospheric conditions. Patients were followed up for 12 months to determine whether airborne CFU levels at the incision sites predicted the incidence of incisional or prosthesis-related infection.

RESULTS

Data were available for 294 patients, 148 in the intervention group and 146 in the control group. CFU density at the incision site was significantly lower in the intervention group than in the control group (P<.001). The density of airborne CFU at the incision site during the procedures was significantly related to the incidence of implant infection (P=.021). Airborne CFU densities were 4 times greater in procedures with implant infection versus no implant infection. All 4 of the observed prosthesis infections occurred in the control group.

CONCLUSION

Reduction of airborne CFU specifically at the incision site during operations may be an effective strategy to reduce prosthesis-related infections. Trial Registration: clinicaltrials.gov Identifier: NCT01610271

Infect Control Hosp Epidemiol 2016;1–8

Microorganisms in Confined Habitats: Microbial Monitoring and Control of Intensive Care Units, Operating Rooms, Cleanrooms and the International Space Station

Indoor environments, where people spend most of their time, are characterized by a specific microbial community, the indoor microbiome. Most indoor environments are connected to the natural environment by high ventilation, but some habitats are more confined: intensive care units, operating rooms, cleanrooms and the international space station (ISS) are extraordinary living and working areas for humans, with a limited exchange with the environment. The purposes for confinement are different: a patient has to be protected from infections (intensive care unit, operating room), product quality has to be assured (cleanrooms), or confinement is necessary due to extreme, health-threatening outer conditions, as on the ISS. The ISS represents the most secluded man-made habitat, constantly inhabited by humans since November 2000 – and, inevitably, also by microorganisms. All of these man-made confined habitats need to be microbiologically monitored and controlled, by e.g., microbial cleaning and disinfection. However, these measures apply constant selective pressures, which support microbes with resistance capacities against antibiotics or chemical and physical stresses and thus facilitate the rise of survival specialists and multi-resistant strains. In this article, we summarize the available data on the microbiome of aforementioned confined habitats. By comparing the different operating, maintenance and monitoring procedures as well as microbial communities therein, we emphasize the importance to properly understand the effects of confinement on the microbial diversity, the possible risks represented by some of these microorganisms and by the evolution of (antibiotic) resistances in such environments – and the need to reassess the current hygiene standards.

Morbidity After Inguinal Lymph Node Dissections: It Is Time for a Change

BACKGROUND

Inguinal lymph node dissection (ILND) for stage 3 melanoma is accompanied by high wound complication rates. During the past decades, several changes in perioperative care have been instituted to decrease the incidence of these complications. This study aimed to evaluate the effect of these different care protocols on wound complications after ILND.

METHODS

A retrospective analysis of prospectively collected data was performed with 240 patients who underwent an ILND in the University Medical Center Groningen between 1989 and 2014. Four groups with different treatment protocols were analyzed: A (≥10 days of bed rest with a Bohler Braun splint), B (10 days of bed rest without a splint), C (5 days of bed rest), and D (1 day of bed rest). The effect of early mobilization, abolishment of the Bohler Braun splint and postural restrictions, and the introduction of prophylactic antibiotics were analyzed.

RESULTS

One or more wound complications occurred in 51.2 % of the patients including wound infection (29.8 %), seroma (21.5 %), wound necrosis (13.6 %), and hematoma (5 %). In consecutive periods, respectively 44.4, 60.3, 44.9 and 55.2 % of the patients experienced wound complications. None of the instituted changes in protocols led to a decrease in wound complications.

CONCLUSION

Changes in perioperative care protocols did not affect the rate of wound complications. Perhaps a change in the surgical procedure itself can lead to the necessary reduction of wound complications after ILND.

Interactions among osteoblastic cells, Staphylococcus aureus, and chitosan-immobilized titanium implants in a postoperative coculture system: An in vitro study

Biomaterial-related infections (BRIs) have become a major challenge in the field of orthopedic implants. In this study, we delved into the problem of BRI and attempted to reduce the possibility of BRI incidence via surface modification of titanium (Ti) with chitosan (SA-CS-Ti). To comprehensively evaluate the anti-infection potential of SA-CS-Ti, we first constructed a postoperative infection (POI) model with varying concentrations of bacteria (10²  CFU/sample and 10⁴  CFU/sample) and a constant number of SaOS-2 cells (10⁵ /sample). Then, we biologically characterized the interactions between the SaOS-2 cells, bacteria, and different Ti implants using the POI model. The results from the osteoblastic cell and bacterial attachment tests demonstrated that the SA-CS-Ti surfaces exhibit superior osteogenic behavior relative to other Ti surfaces studied while showing significant anti-infective activities in the POI model with a low infection ratio (bacteria: cell ratio of 0.001:1) 30 min after infection. Additionally, the SA-CS-Ti surfaces showed significantly reduced (p < 0.05) bacteria proliferation compared to the control Ti surfaces (UN-Ti), demonstrating their antifouling property. The significantly increased (p < 0.05) sensitivity of Staphylococcus. aureus adhered to the SA-CS-Ti surfaces against cefazolin (1 mg/L treatment) and gentamicin (10 mg/L and 100 mg/L treatment) in the coculture system augmented potential of SA-CS-Ti to be used as orthopedic implants. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 586-594, 2016.

Evaluation of the Time-dependent Contamination of Spinal Implants: Prospective Randomized Trial

STUDY DESIGN

Prospective study OBJECTIVE.: To evaluate contamination in spinal implants using a liquid culture medium and the effect of covering an implant set on contamination.

SUMMARY OF BACKGROUND DATA

Postoperative infection rates increase with the use of spinal implants. Because implant contamination may be an important origin for postoperative infections, investigation, evaluation, and taking required precautions to prevent these contaminations are critical.

METHODS

Patients operated on for various spinal pathologies were randomized. The patients were divided into groups of covered and uncovered implant sets. The screw samples were placed in liquid culture medium immediately after opening the implant set. The implant set in the covered group was immediately covered with a sterile surgical towel. A new screw was taken from the implant set and cultured in the liquid culture medium every 30 minutes. At the end of 24 hours, swabs with samples from the liquid culture medium were used to culture blood agar. At the end of 48 hours, the samples with growth were considered contaminated.

RESULTS

Growth started after 30 minutes in the uncovered group, whereas only a single growth was noted after 60 minutes in the covered group. Contamination increased with time in both groups, but more so in the open group. A statistically significant difference in contamination was found between the groups at and after 30 minutes.

CONCLUSION

Contamination increases with time in all implant materials. Contamination rates can be reduced by using simple precautions, such as covering the implant set. Culturing the entire implant samples in liquid culture medium is accepted as a safe and more effective method in evaluating contamination.

LEVEL OF EVIDENCE

2.

Infection prevention in total knee arthroplasty

Periprosthetic joint infections are devastating complications that are difficult and expensive to treat and have a substantial mortality rate. A major goal of modern joint arthroplasty is to minimize these infections. Preoperative factors associated with increased risk of infection include malnutrition, diabetes mellitus, obesity (body mass index >40 kg/m(2)), and rheumatoid arthritis. Administration of appropriate antibiotics before the surgical incision is made is essential to minimize infection. The use of laminar flow rooms, proper skin preparation, limiting operating room traffic, and the use of various wound closure techniques can help to decrease infection rates. Postoperatively, optimal management of indwelling urinary catheters, blood transfusions, and wound drainage also may decrease infection rates.

The appropriate use of neurostimulation of the spinal cord and peripheral nervous system for the treatment of chronic pain and ischemic diseases: the Neuromodulation Appropriateness Consensus Committee

INTRODUCTION

The Neuromodulation Appropriateness Consensus Committee (NACC) of the International Neuromodulation Society (INS) evaluated evidence regarding the safety and efficacy of neurostimulation to treat chronic pain, chronic critical limb ischemia, and refractory angina and recommended appropriate clinical applications.

METHODS

The NACC used literature reviews, expert opinion, clinical experience, and individual research. Authors consulted the Practice Parameters for the Use of Spinal Cord Stimulation in the Treatment of Neuropathic Pain (2006), systematic reviews (1984 to 2013), and prospective and randomized controlled trials (2005 to 2013) identified through PubMed, EMBASE, and Google Scholar.

RESULTS

Neurostimulation is relatively safe because of its minimally invasive and reversible characteristics. Comparison with medical management is difficult, as patients considered for neurostimulation have failed conservative management. Unlike alternative therapies, neurostimulation is not associated with medication-related side effects and has enduring effect. Device-related complications are not uncommon; however, the incidence is becoming less frequent as technology progresses and surgical skills improve. Randomized controlled studies support the efficacy of spinal cord stimulation in treating failed back surgery syndrome and complex regional pain syndrome. Similar studies of neurostimulation for peripheral neuropathic pain, postamputation pain, postherpetic neuralgia, and other causes of nerve injury are needed. International guidelines recommend spinal cord stimulation to treat refractory angina; other indications, such as congestive heart failure, are being investigated.

CONCLUSIONS

Appropriate neurostimulation is safe and effective in some chronic pain conditions. Technological refinements and clinical evidence will continue to expand its use. The NACC seeks to facilitate the efficacy and safety of neurostimulation.

Preventing surgical-site infections: measures other than antibiotics

Surgical-site infections (SSIs) due to intra-operative contamination are chiefly ascribable to airborne particles carrying microorganisms, mainly Staphylococcus aureus, which settle on the surgeon's hands and instruments. SSI prevention therefore rests on minimisation of airborne contaminated particle counts, although these have not been demonstrated to correlate significantly with SSI rates. Maintaining clear air in the operating room classically involves the use of ultra clean ventilation systems combining laminar airflow and high-efficiency particulate air filters to create a physical barrier around the surgical table; in addition to a stringent patient preparation protocol, appropriate equipment, and strict operating room discipline on the part of the surgeon and other staff members. SSI rates in clean surgery, although influenced by the type of procedure and by patient-related factors, are consistently very low, of about 1% to 2%. These low rates, together with the effectiveness of prophylactic antibiotic therapy and the multiplicity of parameters influencing the SSI risk, are major obstacles to the demonstration that a specific measure is effective in decreasing SSIs. As a result, controversy surrounds the usefulness of many measures, including laminar airflow, body exhaust suits, patient preparation techniques, and specific surgical instruments. Impeccable surgical technique and operating room behaviour, in contrast, are clearly essential.

Mold contamination in a controlled hospital environment: a 3-year surveillance in southern Italy

Background

Environmental monitoring of airborne filamentous fungi is necessary to reduce fungal concentrations in operating theaters and in controlled environments, and to prevent infections. The present study reports results of a surveillance of filamentous fungi carried out on samples from air and surfaces in operating theaters and controlled environments in an Italian university hospital.

Methods

Sampling was performed between January 2010 and December 2012 in 32 operating theaters and five departments with high-risk patients. Indoor air specimens were sampled using a microbiological air sampler; Rodac contact plates were used for surface sampling. Fungal isolates were identified at the level of genera and species.

Results

Sixty-one samples (61/465; 13.1%) were positive for molds, with 18 from controlled environments (18/81; 22.2%) and 43 (43/384; 11.2%) from operating theaters. The highest air fungal load (AFL, colony-forming units per cubic meter [CFU/m³]) was recorded in the ophthalmology operating theater, while the pediatric onco-hematology ward had the highest AFL among the wards (47 CFU/m³). The most common fungi identified from culture of air specimens were Aspergillus spp. (91.8%), Penicillium spp., (6%) and Paecilomyces spp. (1.5%). During the study period, a statistically significant increase in CFU over time was recorded in air-controlled environments (p = 0.043), while the increase in AFL in operating theaters was not statistically significant (p = 0.145). Molds were found in 29.1% of samples obtained from surfaces. Aspergillus fumigatus was the most commonly isolated (68.5%).

Conclusions

Our findings will form the basis for action aimed at improving the air and surface quality of these special wards. The lack of any genetic analysis prevented any correlation of fungal environmental contamination with onset of fungal infection, an analysis that will be undertaken in a prospective study in patients admitted to the same hospital.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-014-0595-z) contains supplementary material, which is available to authorized users.

Stockinette application over a non-prepped foot risks proximal contamination

This study sought to determine if there was an increased risk for surgical site contamination during stockinette application for a lower extremity surgery draping technique. Utilizing a simulated, sterile surgical field, stockinettes were applied over 10 cadaver lower extremities that were contaminated with non-pathogenic Escherichia coli on the foot. Of those, five specimens were then disinfected with Chloroprep and another 5 did not undergo any disinfection. All the specimens in which the stockinette was applied over a non-prepped foot showed proximal contamination. No contamination occurred in any of the specimens where the foot was disinfected. Stockinette can be a source of surgical site contamination when placed over a non-prepared foot.

The effect of laminar air flow and door openings on operating room contamination

We evaluate the association of laminar airflow (LAF) and OR traffic with intraoperative contamination rates. Two sterile basins were placed in each room during 81 cases, one inside and one outside the LAF. One Replicate Organism Detection and Counting (RODAC) plate from each basin was sent for culture at successive 30-minute intervals from incision time until wound closure. At successive 30-minute intervals more plates were contaminated outside than inside the LAF. A negative binomial model showed that the bacteria colony forming units (CFU) depended on whether there were any door openings (P=0.02) and the presence of LAF (P=0.003). LAF decreases CFU by 36.6%. LAF independently reduces the risk of contamination and microbial counts for surgeries lasting 90 minutes or less.

Periprosthetic joint infections at a teaching hospital in 1990-2007

BACKGROUND

Periprosthetic joint infections (PJIs) are major complications associated with high costs and substantial morbidity. We sought to evaluate hip and knee arthroplasty infection rates at our hospital, compare them in periods before and after implementation of measures to reduce PJIs (1990-2002 and 2003-2007) and identify associated risk factors.

METHODS

We retrospectively reviewed records of patients who received primary hip or knee total joint prostheses at our centre between Jan. 1, 1990, and Dec. 31, 2007, and were readmitted for the treatment of infection related to their surgery. We also reviewed data from a prospective surveillance protocol of total hip (THA) and knee arthroplasty (TKA) infections that started in November 2005. We ascertained the annual rates of deep, superficial and hematogenous infections.

RESULTS

During the periods studied, 2403 THAs and 1220 TKAs were performed. For THA, the average rates of deep, superficial and hematogenous infections were 2.0%, 0.8% and 0.3%, respectively. For TKA, the rates were 1.6%, 0.7% and 0.2%, respectively. Of 106 infected joints, 84 (79.2%) presented risk factors for infection. Efforts to reduce the infection rate at our institution began in 2003. We achieved a 44% decrease in the deep infection rate for THA (2.5% v. 1.4%; p = 0.06) and a 45% decrease for TKA (2.0% v. 1.1%, p = 0.20) between the periods studied.

CONCLUSION

Knowing the actual infection rate associated with different procedures in specific settings is essential to identify unexpected problems and seek solutions to improve patient care. Although we do not know what specific improvements were successful, we were able to decrease our infection rates to levels comparable to those reported by similar care centres.

Bacterial DNA from orthopedic implants after routine removal

Bacterial 16S rDNA was monitored and identified from orthopedic metallic implants after routine or septic removal from patients in a German hospital. From March to June 2009, 28 metallic implants, 10 human biopsies, and 6 foam dressings from 28 patients were investigated. After analysis of this first collective, the methods were optimized to enhance sensitivity and to reduce interference with human DNA. Then a second collective consisting of 21 metallic implants from 21 patients was investigated from June 2009 to January 2010. In the first collective, 71% of the metallic implants were negative for eubacterial DNA. Pathogens such as Staphylococcus aureus and opportunists such as Lactobacillus rhamnosus were identified in 11% of the samples, whereas the residual 18% positive results were classified as from skin sources or could not be confirmed. Tissue, secretion, and bone samples as well as foam dressings from the same collective also contained pathogens and opportunists. After the optimization of the methods, a considerable increase of positive samples was seen: in the second collective 19 of the 21 metallic implants proved to be positive for eubacterial 16S rDNA. Bacterial DNA from environmental sources was detected in 13 samples, and in 20 specimens, predominantly mostly the skin. Opportunistic pathogens were detected in 19 samples. Interestingly, septic complications did not occur despite the presence of bacterial DNA. The results obtained up to now encourage us not only to continue a directed monitoring of bacterial DNA on orthopedic implants in practice but also to look intensely for possible sources of bacterial contamination during and after insertion or during removal of such implants.

Timing of C-arm drape contamination

BACKGROUND

Surgical site infection remains a concern in orthopedic surgery, and contamination of C-arm covers is a potentially modifiable risk factor.

METHODS

A single-cohort study was conducted using 30 consecutive patients undergoing operative fracture fixation. Cultures were obtained from the C-arm cover after initial draping and every 20 min thereafter. The total number of persons in the operating room (person-hours/h of study time) and the number of door openings were recorded. The C-arm position changes and the time to contamination were monitored.

RESULTS

The median time from the start of the operation to contamination was 20 min. There was a 17% contamination rate on initial draping, 50% at 20 min, 57% at 40 min, and 80% by 80 min. The C-arms in five cases were not contaminated during the surgery. Time to contamination correlated significantly with lateral position changes (correlation [r]=0.64; p=0.003) but was not related to C-arm position changes (r=0.22; p=0.34), number of door openings (r=0.20; p=0.39), or person-hours/h (r=0.04; p=0.85).

CONCLUSIONS

Contamination of the C-arm drape occurs often and early during surgery for orthopedic fractures. We recommend minimal contact with the C-arm to avoid contamination of the surgical field.

Prevalence of bacterial contamination in general operating theaters in selected hospitals in the Gaza Strip, Palestine

OBJECTIVES

This study was conducted in general operating theaters at public and private hospitals in the Gaza Strip, Palestine to determine the prevalence of bacterial contamination of different objects.

METHODS

Swabs were collected from 21 items that were distributed over three categories (equipment, environment and personnel). In total, 243 swabs were collected at pre- and post-operation stages and were cultured and identified using standard microbiological procedures.

RESULTS

The results show that 24.7% of the swabs were contaminated with microorganisms. The equipment, environment and personnel were responsible for 45%, 48.3% and 6.7% of contamination, respectively. The rate (26.9%) of contamination in the post-operation samples was higher than in the pre-operation samples (22.6%), but the difference was not statistically significant. In addition, there was not a statistically significant increase in the prevalence of contamination in private (28.7%) compared to public hospitals (21.8%). Of the seven bacterial genera that were recovered, the highest percentage belonged to Staphylococcus spp. (45.3%) followed by Enterobacter spp. (23.4%).

CONCLUSIONS

This study reveals a moderate percentage of contamination in our public and private hospital general operating theaters, which may increase the risk factors for developing surgical-site infections. These observations justify more attention being paid to infection-control efforts in our hospitals.

Mobile laminar air flow screen for additional operating room ventilation: reduction of intraoperative bacterial contamination during total knee arthroplasty

BACKGROUND

Surgical site infections are important complications in orthopedic surgery. A mobile laminar air flow (LAF) screen could represent a useful addition to an operating room (OR) with conventional turbulent air ventilation (12.5 air changes/h), as it could decrease the bacterial count near the operating field. The purpose of this study was to evaluate LAF efficacy at reducing bacterial contamination in the surgical area during 34 total knee arthroplasties (TKAs).

MATERIALS AND METHODS

The additional unit was used in 17 operations; the LAF was positioned beside the operating table between two of the surgeons, with the air flow directed towards the surgical area (wound). The whole team wore conventional OR clothing and the correct hygiene procedures and rituals were used. Bacterial air contamination (CFU/m(3)) was evaluated in the wound area in 17 operations with the LAF unit and 17 without the LAF unit.

RESULTS

The LAF unit reduced the mean bacterial count in the wound area from 23.5 CFU/m(3) without the LAF to 3.5 CFU/m(3) with the LAF (P < 0.0001), which is below the suggested limit for an OR with ultraclean laminar ventilation. There were no significant differences in the mean bacterial count in the instrument table area: 28.6 CFU/m(3) were recorded with the LAF (N = 6) unit and 30.8 CFU/m(3) (N = 6) without the LAF unit (P = 0.631). During six operations with LAF and six without LAF, particle counts were performed and the number of 0.5 μm particles was analyzed. The particle counts decreased significantly when the LAF unit was used (P = 0.003).

CONCLUSION

When a mobile LAF unit was added to the standard OR ventilation, bacterial contamination of the wound area significantly decreased to below the accepted level for an ultraclean OR, preventing SSI infections.

Sterile surgical helmet system in elective total hip and knee arthroplasty

PURPOSE

To evaluate the sterility of the sterile surgical helmet system (SSHS) during elective total hip and knee arthroplasty in theatres with (n=20) and without (n=20) laminar flow.

METHODS

Three surgeons performed 14 total knee arthroplasties (TKAs) and 6 total hip arthroplasties (THAs) in a laminar flow theatre and 15 TKAs and 5 THAs in a non-laminar flow theatre. An SSHS was used in all the procedures. Samples were taken from the hood at 30-minute intervals during surgery. Swabs were then broken into cooked meat broths for cultivation of organisms. The broths were then directly inoculated onto blood agar and fastidious anaerobic agar for culture of aerobic and anaerobic bacteria, respectively. After 24 hours, these plates were reinoculated with broths that had been incubated for 24 hours. Microbial growth was quantified as 0 (none), 1 (mild), 2 (moderate) and 3 (heavy). Bacterial contamination in the 2 groups at 30, 60 and 90 minutes was compared.

RESULTS

Respectively in the laminar and non-laminar flow theatres, 0 and 9 of the SSHSs showed bacterial growth after direct inoculation, and 14 and 18 of the SSHSs grew 18 and 24 types of organisms in the swab cultures after 24 hours of incubation. Respectively at 30, 60, and 90 minutes, the degree of contamination from direct incubation was significant, but the degree of contamination on swabs after 24 hours of inoculation was not significant. The mean time-dependent contamination after direct inoculation was 0 for the laminar flow group and 0.5, 0.75, and 1.0 for the non-laminar flow group, whereas the corresponding values after 24 hours of incubation were 1.8, 1.8, and 2.6, and 2, 2.75, and 2.95. Coagulase negative Staphylococcus aureus was the most common organism in both groups.

CONCLUSION

80% of SSHSs used were contaminated intra-operatively. Direct contact with the SSHS should be avoided by the operating team during surgery. Routine changing of gloves in case of contact with the SSHS should be practised.