The antimicrobial capacity of embalming solutions: a comparative study

Preparation of Soft Embalmed Cadavers by the Modified Thiel Embalming Technique for Surgical Skill Training and Development of a Universal Quantitative Scoring System to Assess the Suitability of Soft Embalmed Cadavers for Such Training Purposes

Background Cadaver dissection plays an important role in learning anatomy. A surgeon must have a thorough knowledge of anatomy of the operating region to perform safe surgery. Skill laboratories give opportunities to surgeons to practice on cadavers before venturing onto real patients. The most common method of cadaver preservation is through formalin fixation. In the process of fixation, formalin destroys the tissue characteristics and also has issues such as smell, eye irritation, hardening of tissue, and risk of carcinogenesis. The Thiel embalming technique and its modifications were developed to address those issues. Our primary objective was to find the benefits of soft embalmed cadavers over formalin-fixed bodies and, secondly, to find out microbial flora in soft embalmed cadavers. Study design This is a basic study. Methods Four cadavers were prepared for the soft embalming purpose for our workshop for surgeons on spine fixation. Due to unavailability, we replaced 4-chloro-3-methylphenol 1% with phenol 1%. The bodies were preserved in refrigerators at 4°C before being used for the workshop purpose. The delegates and faculties were given a questionnaire to assess their experience of the cadavers in terms of odor, irritation, tissue characteristics, joint mobility, and imaging characteristics. The results were calculated using statistical analysis. Swabs were taken from a few of the cadavers for culture to find the organisms. Results There were 14 questions in the questionnaire, and the data collected were divided into two groups, faculties, and delegates. JASP software was used to analyze the data. The questions addressed various aspects of cadavers such as color, odor, tissue pliability, joint flexibility, imaging characteristics, mucosal irritation, and earlier experience in working with cadavers. Cronbach α was used to find the correlation between the various characteristics analyzed. The authors intend to name the domains being measured: surgical suitability (scores of items 8 to 12), imaging suitability (scores of items 5 and 6), and smell score (scores of items 5 and 6). It can be a guide to constructing and refining a better quantitative scale to measure the "quality of soft-embalmed cadavers for surgical training." Conclusions Skill laboratories give opportunities to young surgeons and trainees to learn and improve their skills before applying them to real patients. This was our first attempt to develop soft embalmed cadavers at our center and our state. We used the parent solution with some variations as per the availability of chemicals at our place and found that the features of the preserved cadavers were good and well-suited to address our purpose. Therefore, with some variations in the parent formulations, centers situated in remote and less developed places can formulate their own solution to develop soft embalmed cadavers and establish cadaver skill laboratories. This will benefit the local surgeons and trainees. The authors tried to develop a few domains through statistical analysis, which can be used to assess and compare the quality of cadavers prepared at various centers.

Incidental finding of Clostridium perfringens on human corpses used for the anatomy course

Post-mortem specimens used for anatomy teaching are commonly embalmed using compositions of chemicals, with the objective to maintain tissue quality and to avoid putrefaction. Monitoring for bacterial or fungal contamination is becoming increasingly important especially when measures are taken to minimize exposure by chemicals such as formaldehyde. In this case, random swabs were taken from six corpses embalmed with ethanol-glycerin and Thiel embalming. Cultures and MALDI-TOF analyses yielded four cases of Clostridium perfringens contamination. C. perfringens is of special interest as a human pathogen. A potential source was identified in the containers filled with the moistening solution. Cross contamination with Clostridium species has likely occurred between corpses sharing the moistening solution and soaking the cover linen directly within the containers. To minimize any risk for those exposed, the moistening solutions were discarded and all equipment thoroughly disinfected. The specimens had to be cremated as they formed a potential source of Clostridium spores. Deviating from previous routines it was formalized that the cover linen must not be submerged in the moistening contains rather than moistening the specimens directly with dedicated vessels. Follow-up analyses yielded no further contamination with C. perfringens.

Dealing with Hidden Threats: The Antimicrobial Effect of the Embalming Process

Individuals naturally carry bacteria and other microbes as part of their natural flora, with some being opportunistic pathogens. Approximately 30% of the population is known to carry Staphylococcus aureus in their nasal cavity, an organism that causes infections ranging from soft tissue abscesses to toxic shock syndrome. This problem is compounded by the presence of antibiotic-resistant strains such as Methicillin-Resistant Staphylococcus aureus (MRSA). Commensal bacteria present on cadavers pose a risk to those who handle the body. As a Medical School Anatomy laboratory that performs hands-on cadaveric dissection, we wanted to know whether the embalming process is sufficient to kill all commensal bacteria that pose a risk to staff and students. Even if these strains do not cause disease in these individuals, secondary transmission could occur to friends and family, who may be at higher risk of acquiring an infection. Embalming is assumed to eliminate all microbial contamination on the body. However, there are limited studies to confirm this. This study characterises the incidence of antibiotic sensitive and resistant bacteria in cadavers donated for medical teaching and research. We have screened for Methicillin-Resistant Organisms (MRO) and Extended-Spectrum Beta-Lactamase (ESBL) producing bacteria. In this study group of cadavers, approximately 46% (16/35) carry an MRO, while 51% (18/35) carry an ESBL positive organism prior to embalming. By determining the organisms’ presence pre- and post-embalming, we can evaluate the embalming procedure’s effectiveness. Our results show embalming eliminates detectable microbes in about 51% (18/35) of the cadavers. MRO dropped by 75% (16 to 4 positive cadavers), while ESBL organisms went down by almost 95% (from 18 to 1 positive cadaver). There was a further decrease in the number of positive cadavers after storage at 4 °C to 6% (2/32). Thus, although the embalming process does not immediately sterilise all the cadavers, prolonged storage at 4 °C can further reduce the number of viable bacteria.

30 years of Thiel embalming - A systematic review on its utility in medical research

In 1992, Walter Thiel described and embalming method that rendered 'lifelike' tissues. Over the last 30 years, the Thiel method has been introduced worldwide for medical training and scientific purposes. This review examines research which can be linked to the use of Thiel embalming. A systematic review was performed to identify articles published in the following categories: research content, disciplines involved, sources and quantities of tissues deployed, and changes in research scope related to changes in the chemical composition of Thiel embalming. 424 publications were included. A number of adaptations to the original Thiel protocol were found, aiming to provide suitable tissue-substitutes in the development of emerging medical technologies or procedures. Musculoskeletal surgery, anesthesia and intensive care were the most common disciplines that used Thiel embalmed tissues for research. Anatomy and biomechanics played a lesser role. An increase over time was observed in research outputs related to the Thiel method, while the number of specimens used per study decreased. The main centers using Thiel embalming were in Graz, Dundee, Sapporo, Bern, Zurich and Ghent, which jointly accounted for more than 54% of all research conducted using this method. Following three decades of use, the Thiel method has evolved into being a well-established embalming technique for research purposes. Its future is challenged by the demanding requirements on both technical facilities and personnel, limitations of certain chemicals for use as fixatives, costs, and questions as to how 'lifelike' the embalmed-tissues are from an objective standpoint, all of which warrants future investigations. This article is protected by copyright. All rights reserved.

The risk of Creutzfeldt-Jakob disease infection in cadaveric surgical training

The usefulness of cadaver surgical training in the clinical field is already well known. In Japan, the number of universities introducing cadaver surgical training is increasing. In addition to formalin fixation, various fixation methods are used, such as the Thiel method, saturated salt solution method, N-vinyl-2-pyrrolidone method, and fresh-frozen cadavers. Although protection against infections during fixation and cadaver surgical training has been implemented in most universities, it is currently inadequate. Furthermore, the possibility of undiagnosed infectious diseases in donors cannot be excluded. Prion diseases, such as Creutzfeldt-Jakob disease, are relatively rare, but they are fatal, with no effective treatment. The abnormal prion protein that causes prion diseases is resistant to formaldehyde and cannot be inactivated by all methods of cadaver fixation presently in use. Recently developed real-time quaking-induced conversion has been reported to be a useful screening method for prion infection. In addition, this article aims to raise awareness of prion diseases in cadaver surgical training by reviewing the current understanding of prion diseases in cadavers and their screening methods.

Evaluation of Information on Body Donation Promotion at Official Websites of Turkish Anatomy Departments

Raising public awareness of body donation is crucial for countries like Turkey that have struggling donation programs. The official websites of anatomy departments may contribute to achieving this goal. Nevertheless, previous studies reported institutional or individual reluctance of departments or anatomists, respectively, due to an expectation of adverse publicity. This study aimed to investigate whether the official websites of Turkish anatomy departments provided information on body donation and analyzed the content of these websites. Websites of anatomy departments at 100 medical faculties were evaluated. Only 12 departments (12%) provided information on body donation with varying content. A thematic analysis of the information provided revealed five main themes. These were (1) legal aspects, (2) significance, (3) acceptance/rejection criteria, (4) availability, and (5) redirection. All departments (n = 12, 100%) outlined the legal aspects of body donation, seven departments (58%) highlighted the significance of body donation, seven departments (58%) provided contact information for potential donors, five departments (41%) covered acceptance/rejection criteria, and three departments (25%) provided a link to the official website of the Turkish Society of Anatomy and Clinical Anatomy. Thus, Turkish anatomy departments were reluctant to provide information on body donation, and the content of provided information varied greatly among departments. This lack of information, coordination, and participation in existing awareness activities for body donation in anatomy department websites may be contributing to the low numbers of body donations and donor registrations seen nationally.

Advanced training in laparoscopic gastrointestinal surgical procedures using Genelyn®-embalmed human cadavers: A novel model

Background:

Human cadaver is ideal for learning and acquiring new surgical skills. While cadavers preserved using Thiel’s embalming method are commonly used for training in laparoscopic surgery, it is a cumbersome technique. We report our experience of using Genelyn^®-embalmed cadavers for training in advanced laparoscopic gastrointestinal procedures.

Materials and Methods:

A cross-sectional satisfaction survey corresponding to level 1 of the Kirkpatrick model for training evaluation was performed among 19 participants of advanced laparoscopy surgical skills training workshop, in December 2019, using Genelyn^®-embalmed cadavers. Visual, haptic and tactile characteristics of the organs and tissues were assessed along with overall satisfaction of the workshop using Likert scale.

Results:

Five Genelyn^®-embalmed cadavers were used for the workshop. All the 19 participants perceived that the cadavers were odourless and allowed adequate insufflation for laparoscopic procedures. Most of the participants(n=16, 84%) agreed that the appearance and tactile fidelity of the solid organs, luminal structures and tissues in Genelyn^®-embalmed cadavers were similar to that of a live patient. There was a strong agreement among participants that the workshop will help improve the laparoscopic skills(median Likert score–4).

Conclusion:

The participants of the surgical skill training workshop felt that the Genelyn^®-embalmed cadavers were ideal for use in practicing advanced laparoscopic procedures.

The Unintentional Effects on Body Donation Programs of a Competency-Based Curriculum in Postgraduate Medical Education

As medical programs place increasing importance on competency-based training and surgical simulations for residents, anatomy laboratories, and body donation programs find themselves in a position of adapting to changing demands. To better assess the demand for "life-like" cadaveric specimens and evaluate the possible impacts that competency-based medical education could have upon the body donation program of McGill University, Canada, the authors tracked, over the course of the last 10 years, the number of soft-embalmed specimens, along with the number of teaching sessions and the residents enrolled in competency-based programs that are using cadaveric material. The results reveal that the number of soft-embalmed specimens used within residency training increased from 5 in 2009 to 35 in 2019, representing an increase from 6% of bodies to 36.5% of the total number of body donors embalmed in this institution. Correspondingly, the number of annual teaching sessions for residents increased from 19 in 2012 to 116 in 2019. These increases in teaching are correlated with increasing number of residents enrolled in competency-based programs over the last 3 years (Pearson r ranging from 0.9705 to 0.9903, and R² ranging from 0.9418 to 0.9808). Those results suggest that the new skill-centered curricula which require residents to perform specific tasks within realistic settings, exhibit a growing demand for "life-like" cadaveric specimens. Institutions' body donation programs must, therefore, adapt to those greater need for cadaveric specimens, which presents many challenges, ranging from the logistical to the ethical.

Screening algorithms for HBV, HCV, HIV and syphilis in an anatomical donation program

BACKGROUND

Users of anatomical donors are at risk of exposure to bloodborne pathogens. This study evaluated screening algorithms for hepatitis B and C virus, human immunodeficiency virus and Treponema pallidum during donor allocation and assessed the impact of postmortem time on hemolysis and how hemolysis affects test results and donor discard rate.

METHODS

From 2011 to 2018, demographic data of anatomical donors, time of postmortem blood sampling, presence of sample hemolysis, serological test results (negative; active infection; false reactive screening test; historic infection; inconclusive; technically impracticable) and the actual donor allocation were collected.

RESULTS

Donors (n = 537) had a mean age of 77.53 ± 13.67 (24-103) year. Nine (1.68%) had laboratory test results indicative for active infection for hepatitis B (n = 1) and C virus (n = 2), human immunodeficiency virus (n = 5) and T. pallidum (n = 1). Negative screenings ranged from 74.67 to 97.58%, depending on the pathogen. According to the original screening algorithms, 479 (89.20%) donors should have been accepted. In practice, a donor acceptance rate of 91.20% was found. Analysis of potential donor allocation interpretation obstacles resulted in simplification of the in-house laboratory testing algorithms and addition of a nucleic acid test to increase the reliability for identification of active (acute) human immunodeficiency virus infection. Hemolysis was more common when sampling was performed more than 24 h after death (p < 0.001). Hemolytic samples more frequently showed a reactive or indeterminate human immunodeficiency virus test result (p < 0.001). Screening for human immunodeficiency virus and T. pallidum was technically more impracticable when hemolysis was present (p = 0.042 and p = 0.003, respectively). Donors with hemolytic blood samples were more often discarded (46.88%) compared to bodies with non-hemolytic samples (6.32%) (p < 0.001).

CONCLUSIONS

Despite the implementation of donor screening algorithms, a significant number of bodies have an inconsistent allocation. New algorithms, to be evaluated in future research, were suggested. Early postmortem blood sampling is key as hemolysis can influence certain test results and donor allocation.

Forensic Implications of Anatomical Education and Surgical Training With Cadavers

Anatomical education and surgical training with cadavers are usually considered an appropriate method of teaching, above all for all surgeons at various levels. Indeed, in such a way they put into practice and exercise a procedure before performing it live, reducing the learning curve in a safe environment and the risks for the patients. Really, up to now it is not clear if the nonuse of the cadavers for anatomical education and surgical training can have also forensic implications. A substantial literature research was used for this review, based on PubMed and Web of Science database. From this review, it is clear that the cadaveric training could be considered mandatory, both for surgeons and for medical students, leading to a series of questions with forensic implications. Indeed, there are many evidences that a cadaver lab can improve the learning curve of a surgeon, above all in the first part of the curve, in which frequent and severe complications are possible. Consequently, a medical responsibility for residents and surgeons which perform a procedure without adequate training could be advised, but also for hospital, that has to guarantee a sufficient training for its surgeons and other specialists through cadaver labs. Surely, this type of training could help to improve the practical skills of surgeons working in small hospitals, where some procedures are rare. Cadaver studies can permit a better evaluation of safety and efficacy of new surgical devices by surgeons, avoiding using patients as ≪guinea pigs≫. Indeed, a legal responsibility for a surgeon and other specialists could exist in the use of a new device without an apparent regulatory oversight. For a good medical practice, the surgeons should communicate to the patient the unsure procedural risks, making sure the patients' full understanding about the novelty of the procedure and that they have used this technique on few, if any, patients before. Cadaver training could represent a shortcut in the standard training process, increasing both the surgeon learning curve and patient confidence. Forensic clinical anatomy can supervise and support all these aspects of the formation and of the use of cadaver training.

Low cost and effective reduction of formaldehyde in gross anatomy: long throw nozzles and formaldehyde destruction using InfuTrace™

Formaldehyde is extraordinarily effective for fixation of human corpses and is routinely used in embalming solutions in anatomical dissection courses all over the world. High concentrations in vapors emitted from corpses embalmed with formaldehyde make it necessary to reduce the emission from cadavers for fulfilling tightening permissible exposure limits (PEL) worldwide. The study provides possible solutions to a problem faced by many anatomy labs. The emission of 50 human corpses was examined using 240 active personal and stationary samples with sampling tubes placed in the breathing area of probands or directly above the corpses. For measuring formaldehyde exposures along the dissection course, air samples were collected during the progress of dissection. Best results were achieved by a combination of post-embalming treatment with InfuTrace™, a formaldehyde binding solution applied to corpses fixed with 3% formaldehyde, and a modified ventilation system consisting of three long throw nozzles mounted vertically at the ceiling above the longitudinal axis of each dissection table. In this scenario, the inhalative exposure for students and teachers did not exceed 0.1 ppm during muscle dissection and 0.041 ppm during organ dissection, which are both dissection steps linked to high emission rates. The data emphasizes the necessity to use a combination of different methods - chemical polymerization of formaldehyde combined with a modified ventilation system - to reduce formaldehyde air loads far below the German PEL (0.3 ppm) and even the Japanese PEL (0.1 ppm) when using a standard 3%-formaldehyde fixation.

Phenoxyethanol-Based Embalming for Anatomy Teaching: An 18 Years' Experience with Crosado Embalming at the University of Otago in New Zealand

Embalming fixatives such as formaldehyde and phenol have been associated with occupational health hazards. While anatomists aim at replacing these chemicals, this seems presently unfeasible in particular for formaldehyde. Furthermore, fixation protocols usually require well-equipped facilities with highly experienced staff to achieve good fixation results in spite of only a minimal use of formaldehyde. Combining these aspects, a technique robust enough to be carried out by morticians is presented, resulting in durable tissues with minimal formaldehyde use. An embalming protocol involving phenoxyethanol was established, using concentrations of 7 and 1.5 Vol% of phenoxyethanol in the fixative and the conservation fluid, respectively. Visual, haptic, histological, and biomechanical properties and their perceived potential to positively influence student learning outcomes were compared to standard embalming techniques. The phenoxyethanol technique provides esthetic, durable, and odorless tissues. Bleaching is less pronounced compared to ethanol- or formaldehyde-based protocols. The tissues remain pliable following the phenoxyethanol-based embalming and can be used for biomechanical experiments to some extent. Phenoxyethanol-fixed tissues are well suited for undergraduate teaching with perceived positive learning outcomes and partly for postgraduate training. Phenoxyethanol tissues provide the option to obtain well-preserved histology samples, similar to those derived from formaldehyde. The provided protocol helps replace the use of phenol and formaldehyde for conservation purposes and minimizes the use of formaldehyde for the initial injection fixation. Phenoxyethanol-based embalming forms an effective alternative to standard embalming techniques for human cadavers. It is simple to use, allowing fixation procedures to be carried out in less sophisticated facilities with non-anatomy staff.