Methods to Minimize the Risks of Creutzfeldt-Jakob Disease Transmission by Surgical Procedures: Where to Set the Standard?

Carbon footprints in minimally invasive surgery: Good patient outcomes, but costly for the environment

Advancements in technology and surgical training programs have increased the adaptability of minimally invasive surgery (MIS). Gastrointestinal MIS is superior to its open counterparts regarding post-operative morbidity and mortality. MIS has become the first-line surgical intervention for some types of gastrointestinal surgery, such as laparoscopic cholecystectomy and appendicectomy. Carbon dioxide (CO2) is the main gas used for insufflation in MIS. CO2 contributes 9%-26% of the greenhouse effect, resulting in global warming. The rise in global CO2 concentration since 2000 is about 20 ppm per decade, up to 10 times faster than any sustained rise in CO2 during the past 800000 years. Since 1970, there has been a steady yet worrying increase in average global temperature by 1.7 °C per century. A recent systematic review of the carbon footprint in MIS showed a range of 6-814 kg of CO2 emission per surgery, with higher CO2 emission following robotic compared to laparoscopic surgery. However, with superior benefits of MIS over open surgery, this poses an ethical dilemma to surgeons. A recent survey in the United Kingdom of 130 surgeons showed that the majority (94%) were concerned with climate change but felt that the lack of leadership was a barrier to improving environmental sustainability. Given the deleterious environmental effects of MIS, this study aims to summarize the trends of MIS and its carbon footprint, awareness and attitudes towards this issue, and efforts and challenges to ensuring environmental sustainability.

Kinetics of the reduction of Creutzfeldt-Jakob disease prion seeding activity by steam sterilization support the use of validated 134°C programmes

BACKGROUND

Prions are renowned for their distinct resistance to chemical or physical inactivation, including steam sterilization. Impaired efficacy of inactivation poses a risk to patients for iatrogenic transmission of Creutzfeldt-Jakob disease (CJD) via contaminated surgical instruments.

AIMS

Most established prion inactivation methods were validated against scrapie agents, although those were found to be generally less thermostable than human prions. Thus, knowledge gaps regarding steam-sterilization kinetics of CJD prions should be filled and current guidelines reviewed accordingly.

METHODS

Prion inactivation through widely recommended steam sterilization at 134°C was assessed for several holding times by analysing the residual prion seeding activity using protein misfolding cyclic amplification (PMCA).

FINDINGS

Scrapie 263K was found to be the least thermoresistant prion strain showing no seeding activity after 1.5 min at 134°C, while variant CJD was the most stable one demonstrating some seeding activity even after 18 min of steam sterilization. Sporadic CJD subtype VV2 exhibited residual seeding activity after 3 min, but no detectable activity after 5 min at 134°C.

CONCLUSION

Validated steam sterilization for 5 min at 134°C as previously recommended for the routine reprocessing of surgical instruments in contact with high-risk tissues is able to substantially reduce the seeding activity of CJD agents, provided that no fixating chemical disinfection has been performed prior to sterilization and that thorough cleaning has reduced the protein load on the surface to less than 100 μg per instrument.

Improved surveillance of surgical instruments reprocessing following the variant Creutzfeldt-Jakob disease crisis in England: findings from a three-year survey

BACKGROUND

Sensitive, direct protein-detection methods are now recommended for the inspection of reprocessed reusable surgical instruments in England to reduce the risk of prion transmission.

AIM

To implement an established, highly sensitive method to quantify proteinaceous residues on reprocessed instruments in a Sterile Services Department (SSD) and evaluate its potential impact on service provision.

METHODS

We introduced highly sensitive epifluorescence (EDIC/EF) microscopy in a large SSD. Over three years, we periodically tested two models of washer disinfector using stainless-steel tokens spiked with mouse brain homogenate or Browne test soil for comparison. We also obtained data and feedback from staff who had been using EDIC/EF to examine almost 3000 reprocessed instruments.

FINDINGS

All reprocessed test surfaces harboured residual contamination (up to 258.4 ng from 1-μg spikes). Proximity between surfaces affected decontamination efficacy and allowed cross-contamination. Up to 50 ng de novo proteinaceous contamination was deposited on control surfaces after a single automated washer disinfector (AWD) cycle. The test soil behaved differently than real tissue contamination. SSD staff observed proteinaceous residues on most reprocessed instruments using EDIC/EF, which can detect far smaller amounts than the currently accepted national threshold of 5 μg per side.

CONCLUSIONS

Implementing recent national guidelines to address the prions concern proved an eye-opener. Microscopic levels of proteins remain on many reprocessed instruments. The impact most of these residues, potentially including prions, may have on subsequent patients after sterilization remains debatable. Improving surveillance capability in SSDs can support decision making and raise the standards of surgical instruments reprocessing.

Observance of Sterilization Protocol Guideline Procedures of Critical Instruments for Preventing Iatrogenic Transmission of Creutzfeldt-Jakob Disease in Dental Practice in France, 2017

Effective sterilization of reusable instruments contaminated by Creutzfeldt–Jakob disease in dental care is a crucial issue for public health. The present cross-sectional study investigated how the recommended procedures for sterilization were implemented by French dental practices in real-world settings. A sample of dental practices was selected in the French Rhône-Alpes region. Data were collected by a self-questionnaire in 2016. Sterilization procedures (n = 33) were classified into 4 groups: (1) Pre-sterilization cleaning of reusable instruments; (2) Biological verification of sterilization cycles—Monitoring steam sterilization procedures; (3) Autoclave performance and practitioner knowledge of autoclave use; (4) Monitoring and documentation of sterilization procedures—Tracking and tracing the instrumentation. Answers were provided per procedure, along with the global implementation of procedures within a group (over 80% correctly performed). Then it was verified how adherence to procedure groups varied with the size of the dental practice and the proportion of dental assistants within the team. Among the 179 questionnaires available for the analyses, adherence to the recommended procedures of sterilization noticeably varied between practices, from 20.7% to 82.6%. The median percentages of procedures correctly implemented per practice were 58.1%, 50.9%, 69.2% and 58.2%, in Groups 1, 2, 3 and 4, respectively (corresponding percentages for performing over 80% of the procedures in the group: 23.4%, 6.6%, 46.6% and 38.6%). Dental practices ≥ 3 dental units performed significantly better (>80%) procedures of Groups 2 and 4 (p = 0.01 and p = 0.002, respectively), while no other significant associations emerged. As a rule, practices complied poorly with the recommended procedures, despite partially improved results in bigger practices. Specific training regarding sterilization procedures and a better understanding of the reasons leading to their non-compliance are needed.

Public health: surveillance, infection prevention, and control

Human prion diseases, though relatively rare, remain an ongoing public health problem. They are fatal diseases, with unconventional host responses and no early diagnostic tests or robust treatments. Public health measures were put in place to protect the food chain in the United Kingdom from the late 1980s, with similar measures following elsewhere. However, human prion diseases are transmissible through other routes, including through blood transfusion and surgery. As a result, the public health threat remains for all forms of human prion diseases and makes continued surveillance and infection prevention and control imperative.

Pathogenic prion protein fragment (PrP106-126) promotes human immunodeficiency virus type-1 infection in peripheral blood monocyte-derived macrophages

Transfusion of blood and blood products contaminated with the pathogenic form of prion protein Prp(sc), thought to be the causative agent of variant a Creutzfeldt-Jakob disease (vCJD), may result in serious consequences in recipients with a compromised immune system, for example, as seen in HIV-1 infection. In the present study, we demonstrate that treatment of peripheral blood monocyte-derived macrophages (MDM) with PrP106-126, a synthetic domain of PrP(sc) that has intrinsic functional activities related to the full-length protein, markedly increased their susceptibility to HIV-1 infection, induced cytokine secretion, and enhanced their migratory behavior in response to N-formyl-l-methionyl-l-leucyl-l-phenylalanine (fMLP). Live-cell imaging of MDM cultured in the presence of PrP106-126 showed large cell clusters indicative of cellular activation. Tyrosine kinase inhibitor STI-571, protein kinase C inhibitor K252B, and cyclin-dependent kinase inhibitor olomoucine attenuated PrP106-126-induced altered MDM functions. These findings delineate a previously undefined functional role of PrP106-126-mediated host cell response in promoting HIV-1 pathogenesis.

Prion diseases as transmissible zoonotic diseases

Prion diseases, also called transmissible spongiform encephalopathies (TSEs), lead to neurological dysfunction in animals and are fatal. Infectious prion proteins are causative agents of many mammalian TSEs, including scrapie (in sheep), chronic wasting disease (in deer and elk), bovine spongiform encephalopathy (BSE; in cattle), and Creutzfeldt-Jakob disease (CJD; in humans). BSE, better known as mad cow disease, is among the many recently discovered zoonotic diseases. BSE cases were first reported in the United Kingdom in 1986. Variant CJD (vCJD) is a disease that was first detected in 1996, which affects humans and is linked to the BSE epidemic in cattle. vCJD is presumed to be caused by consumption of contaminated meat and other food products derived from affected cattle. The BSE epidemic peaked in 1992 and decreased thereafter; this decline is continuing sharply owing to intensive surveillance and screening programs in the Western world. However, there are still new outbreaks and/or progression of prion diseases, including atypical BSE, and iatrogenic CJD and vCJD via organ transplantation and blood transfusion. This paper summarizes studies on prions, particularly on prion molecular mechanisms, BSE, vCJD, and diagnostic procedures. Risk perception and communication policies of the European Union for the prevention of prion diseases are also addressed to provide recommendations for appropriate government policies in Korea.

Application of rapid read-out cleaning indicators for improved process control in hospital sterile services departments

BACKGROUND

Heightened awareness of the importance of cleaning has led to an emphasis on automated systems for the decontamination of re-usable medical devices. The authors have previously described an enzymatic indicator system, based on thermostable adenylate kinases (tAK), for quantitative monitoring of automated cleaning processes within hospital sterile services departments (SSDs).

AIM

To evaluate tAK indicators for routine process monitoring across a range of SSDs with different cleaning chemistries and different automated washer disinfectors (AWDs).

METHODS

tAK indicator devices and alternative industry test indicators were included in five independent cleaning cycles in each of eight different AWDs. Residual tAK post wash was determined by a coupled luciferase assay using a modified hygiene monitoring system.

FINDINGS

In all cases, with the exception of a single test, the alternative indicators showed that cleaning had been adequate. They were not able to discriminate between the performance of different processes. In contrast, the tAK indicators were able to resolve differences in the performance of processes across the different SSDs. Where the tAK indicators identified cleaning to the limits of detection of the assay, this demonstrated a log10 enzyme removal factor of >5.69.

CONCLUSION

The results suggest that tAK indicators are suitable for providing improved process control for automated cleaning processes, being able to distinguish between wash performance in different hospital settings and between individual process runs. This technology is believed to be a useful addition to routine AWD performance qualification when used as a daily or weekly test.

Electrolysis-assisted sonication for removal of proteinaceous contamination from surgical grade stainless steel

BACKGROUND

Current methods used for the detection of residual proteinaceous contamination vary in sensitivity and specificity. This is of concern because it increases the risk for transmission of neurodegenerative diseases such as spongiform encephalopathies.

AIM

To determine the effectiveness of electrolysis-assisted sonication (EAS) for removing residual proteinaceous contamination from surgical grade stainless steel.

METHODS

EAS was used to clean surgical grade 316L stainless steel that had been contaminated with the protein bovine serum albumin. Using nitrogen, an abundant element in proteins, as a marker for the presence of protein, X-ray photoelectron spectroscopy (XPS) was used to quantify the amount of protein remaining on the substrate surface. Cathodic, anodic and dual polarization modes of EAS were investigated using 0.1% NaCl solution (w/v, in deionized water) as the electrolyte medium and 13 V as the polarization voltage.

FINDING

EAS under dual polarization was found to be the most effective method for removing the residual protein layer down to an estimated XPS detection limit of 10 ng/cm(2). Surface roughness and hardness of the stainless steel remained unchanged following EAS treatment, indicating that the procedure does not compromise the material's properties.

CONCLUSION

This relatively inexpensive and quick method of cleaning medical devices using an easily accessible salt-based electrolyte solution may offer a cost-effective strategy for cleaning medical and dental devices made of stainless steel in the future.

General principles for the regeneration of bone and cartilage

For the regeneration of bone and cartilage, mesenchymal stem cells are currently used invitro and in-vivo. For bone, the existence of viable cells, scaffolds, mechanical environment, growth factors and vascularization are of paramount importance. Mesenchymal stem cells can be harvested from the bone marrow using minimally invasive techniques. Centrifugation can increase the number of transplanted cells per volume. The use of cell therapy is under current clinical investigation and the benefit from these systems has to be proven in level I studies. For cartilage, current techniques recruiting stem cells from the subchondral bone have been demonstrated to be nearly as effective as autologous chondrocyte transplantation, requiring less invasive surgery. The efficacy of mesenchymal stem cell concentrates remains to be proven. There is high potential for tissue engineered joint surfaces to become an option for joint surface defects and degeneration.

Notification and support for people exposed to the risk of Creutzfeldt-Jakob disease (CJD) (or other prion diseases) through medical treatment (iatrogenically)

BACKGROUND

Creutzfeldt-Jakob disease (CJD) and variant CJD (vCJD) are rare and always-fatal diseases transmissible via certain medical procedures. If a person is exposed to the disease risk through medical treatment, they may need to be notified of this to prevent them passing the risk to others in healthcare settings and to enable additional infection control measures to be put in place for certain procedures. As CJD is incurable, and unable to be screened for or effectively treated, communicating this risk information after an exposure incident may have significant implications for the person at risk, their families/ carers and healthcare professionals. The best ways to notify people of their exposure to the risk of CJD or vCJD, and to support them subsequently, are currently unknown.

OBJECTIVES

To evaluate the effects of interventions to notify and support consumers (patients and their family members or carers) in situations where exposure to the risk of CJD or vCJD has occurred as a result of medical treatment (iatrogenically), on consumer, healthcare provider and healthcare system outcomes.

SEARCH STRATEGY

We searched the Cochrane Consumers and Communication Review Group Specialised Register (10 February, 2009), the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1 2009), MEDLINE (OVID SP), EMBASE (OVID SP), PsycINFO (OVID SP), CINAHL (EBSCO Host), Current Contents (OVID SP) and Dissertation Abstracts (Proquest) from start date to February 2009. We searched MEDLINE In-process and Other Non-indexed Citations (OVID SP) and Sociological Abstracts (CSA) in November 2009. We searched reference lists, websites, and contacted consumer groups and experts for details of relevant research.

SELECTION CRITERIA

Randomised and quasi-randomised controlled studies, controlled before-and-after studies and interrupted time series analyses assessing the effects of any intervention to communicate with (notify or support) people exposed to the risk of CJD or vCJD through medical treatment were included. We sought outcomes relevant to consumers, health providers and health services, including both benefits and harms.

DATA COLLECTION AND ANALYSIS

Cochrane reviewTwo authors independently assessed studies for inclusion against selection criteria, and would have applied standard Cochrane review methodology were any studies identified.Thematic synthesisWe also conducted a thematic synthesis by systematically identifying and screening those studies that met the same population, intervention and outcome criteria as the Cochrane review, but that were identified from the broader literature providing evidence on policy implementation and consumer experiences. We systematically extracted and synthesised the data from these studies to produce a thematic synthesis, presented in appendices to this Cochrane review, which assembles evidence on the views, experiences and acceptability of notification and support strategies for people at risk.

MAIN RESULTS

Results of the Cochrane reviewNo studies meeting the study design criteria were identified for inclusion in this Cochrane review.Results of thematic synthesisIn total, 49 studies and pieces of literature meeting the same population, intervention and outcome criteria as the Cochrane review, but identified from the broader literature providing evidence on policy implementation and consumer experiences, were included and formed the basis of a thematic synthesis, and which is presented in appendices to this Cochrane review. The thematic synthesis indicates that ideally communication may be considered as a longitudinal multicomponent programme, ensuring that notification and support are coordinated; that communication is tailored and responsive to need; and that activities to support individual risk communication, such as widespread education and monitoring of access to health care for those at risk, are in place. The thematic synthesis also indicates that poor communication practices may have negative impacts or cause harm, such as discrimination in accessing health care.

AUTHORS' CONCLUSIONS

There is insufficient rigorous evidence to determine the effects of interventions to notify people at CJD or vCJD risk and to support them subsequently, or to identify the best approach to communication in these situations. The thematic synthesis can be used to inform policy and practice decisions for communicating with people at risk in the absence of rigorous evaluative studies.

[Acquired human prion diseases--past and present issues]

Transmissible spongiform encephalopathies, or prion diseases, are fatal neurodegenerative disorders. In aetiological viewpoint, human prion diseases are classified into 1) sporadic Creutzfeldt-Jakob disease (CJD) which comprises 80-90% of the total population of human prion disaeses, 2) inherited forms, and 3) acquired types by prion-contaminated surgical instruments, biopharmaceuticals or foodstuffs. The diseases cause an accumulation of the disease-associated form(s) of prion protein (PrP(Sc)) in the central nervous system. PrP(Sc) is regarded as the entity of prion agents and generally exerts infectivity, irrespective of its origin being from the sporadic cases or the inherited cases. Variant CJD (vCJD), first identified in the United Kingdom (UK) in 1996, is an acquired type of human CJD by oral intake of BSE prion. Cumulative numbers of 215 patients in the world have been reported for definite or probable vCJD cases according to the UK National Creutzfeldt-Jakob Disease Surveillance Unit by September, 2009. Different from sporadic CJD cases, vCJD patients show an accumulation of PrP(Sc) in spleen and tonsils. Such distribution of PrP(Sc) in lymphoid tissues raised clinical concern about the potential infectivity in the blood or blood components used for blood transfusion. To date, five instances of probable transfusion-mediated transmission of vCJD prion have been found in UK. Here we review the past and the present issues about the acquired human prion diseases.

Influence of Usage History, Instrument Complexity, and Different Cleaning Procedures on the Cleanliness of Blood-Contaminated Dental Surgical Instruments

Our study assessed the factors that influence the resistance of blood residues on dental surgical instruments to washer-disinfector-based cleaning procedures in a clinical setting. The use of 2 additional cleaning methods—presoaking and scrubbing by hand—and the use of newer and/or less structurally complex instruments significantly increased the efficacy of washer-disinfector cleaning.

Rapid fracture healing in a patient with inherited prion disease

There do not appear to be any reports or guidelines in the published literature regarding the outcomes of operative or conservative management of fractures in patients with known prion disease. This case report may be helpful in the clinical management of fractures in such patients.

Prion disease transmission: can we apply standard precautions to prevent or reduce risks?

Prion diseases present unique challenges to healthcare facilities, both in the care and treatment of patients. A significant cause for concern is in the routine reprocessing of medical devices used on patients and how disease transmission can be prevented on the reuse of devices. Investigations have shown that prion disease can be transmitted on medical devices, which can be a concern given the long incubation times associated with these diseases and that guidelines to control transmission only really apply in a small number of known or at risk cases. It is only recently that medical device-associated cleaning, disinfection and sterilization technologies have been investigated and the results of these studies are summarized in this report. The evidence would suggest that many simple decontamination steps can be applied to dramatically reduce the risks to patients, but the research has also given some surprises. Overall, it is reasonable to expect that standard precautions will be able to be applied both today as well as in the future to reduce the risk of prion disease transmission as well as the many other human pathogen concerns, although this may mean changes in some of our practices.

Implications for Creutzfeldt-Jakob Disease (CJD) in Dentistry: a Review of Current Knowledge

This review explores our current understanding of the risks of (variant) Creutzfeldt-Jakob disease transmission via dental practice, and whether they merit the rigorous enforcement of improved standards of instrument cleaning and decontamination. The recognition of prions as novel infectious agents in humans has caused significant concern among the public and medical professionals alike. Creutzfeldt-Jakob disease (CJD) in humans has been shown to be transmissible via several routes, including transplantation, contaminated medical products, and via neurosurgery. While the likelihood of transmission via dentistry is undoubtedly very low, this may be amplified considerably by unknown risk factors, such as disease prevalence (particularly in the UK), altered tissue distribution of vCJD, and the failure of decontamination processes to address the inactivation of prions adequately. Since current diagnostic techniques are unable to detect PrPSc in human dental tissues, there is limited evidence for the presence of infectivity. Given these uncertainties, the control of risk by reinforced and improved decontamination practices seems the most appropriate response.

Spatial clusters of Creutzfeldt-Jakob disease mortality in Japan between 1995 and 2004

BACKGROUND

There is suggested to be a geographical difference in Creutzfeldt-Jakob disease (CJD) mortality in Japan. We performed a study to detect localized clusters and hot-spot areas of deaths from CJD in Japan during the 10-year period from 1995 to 2004.

METHODS

The diagnosis of CJD was taken from the death certificate (coded as A81.0 in the ICD-10). A total number of 1,168 CJD deaths (500 males and 668 females) were used for analysis using empirical Bayes estimates of standardized mortality ratios and the flexible spatial scan statistic to detect clusters. To detect the most likely cluster, p values were obtained using Monte Carlo hypothesis testing (with p < 0.05 as statistical significance).

RESULTS

The most likely cluster of CJD mortality was located in the northwest region from the base of Mt. Fuji, stretching over the two neighboring prefectures of Yamanashi and Shizuoka (relative risk = 2.28, p = 0.021). Some other clusters were detected but were not significant.

CONCLUSIONS

The present study supports the evidence of geographical clustering of deaths from CJD at a specific location in Japan.