Effectiveness of various methods of formaldehyde neutralization using monoethanolamine

Formaldehyde is the most commonly used fixative chemical for the preservation of human cadavers used for educational purposes in the United States. Formaldehyde is also a known carcinogenic agent whose exposure level is regulated by guidelines of the Occupational Safety and Health Administration. Various methods for formaldehyde neutralization exist, yet many donations programs do not take any steps to neutralize the formaldehyde in embalmed donor bodies. The effectiveness of monoethanolamine (MEA) in neutralizing formaldehyde is well documented when used as a final injection during embalming. The purpose of this study is to report the effectiveness of several post‐embalming techniques of formaldehyde neutralization. Twenty‐four donor bodies were assigned to four experimental groups of six. For the three experimental groups, the techniques tested involve delivery of a 20:1 dilution of deionized water:MEA via recannulization and gravity flow infusion, compartment injection, and alternate wetting solution containing four percent MEA. Our results indicated that spray bottle delivery was not effective in neutralization of formaldehyde compared to the control group, but that formaldehyde levels decreased when recannulization or compartment injection were used. The most effective method of formaldehyde neutralization was compartment injection of MEA solution (P < 0.01). The results of this study indicate that, in situations where MEA is not used as a final infusion during embalming, compartment injection of MEA solution is an effective method of formaldehyde neutralization. Clin. Anat. 28:449–454, 2015. © 2015 Wiley Periodicals, Inc.     

Preservation of neural tissue with a formaldehyde‐free phenol‐based embalming protocol

The adverse effects formaldehyde fixation has on tissues both gross anatomically and histologically are well documented. Consequently, researchers are seeking alternative embalming techniques that better preserve in vivo characteristics of tissues. Phenol‐based embalming is one method that has shown promise in its ability to adequately preserve the in vivo qualities of tissues through preliminary explorations at the gross anatomical level. The literature on phenol‐based embalming is currently scarce, especially with regard to its effects on tissues at the microscopic level. For the current study we aimed to document the histologic effects of a formaldehyde‐free phenol‐based embalming solution on neural tissue, with the hope of providing novel insight into the effects of soft‐embalming on tissues at the microscopic level. Cerebral and cerebellar tissue obtained from porcine brains was fixed in phenol‐ and formaldehyde‐based fixatives; the latter served as a control. Fixed samples were processed for histological analysis. The phenol‐based embalming solution provided excellent preservation of the cerebral and cerebellar tissue morphology. Of note was the decrease in separation artifact seen in both tissue types relative to the control tissue, as well as anomalous circular artifacts in the white matter. The results of this study indicate that the phenol‐based embalming solution preserves neural tissue at the histological level, perhaps superiorly in many aspects when compared to the formaldehyde‐fixed samples. Further investigations of both gross anatomy and histology are recommended on the basis of these promising new findings to determine its potential utilities within research and education. Clin. Anat. 32:224–230, 2019. © 2018 Wiley Periodicals, Inc.     

Flammability and combustion hazard of preserved human tissues

Preservation techniques have evolved over the years to respond to the need of longer dissection periods, with formaldehyde being widely used for this purpose. In recent years, efforts have been focusing on reducing the health hazards of this fixative and the rigidity of the tissues embalmed with it. With every embalming technique that they are either developing or resurrecting from various protocols, institutions need to assess the fire and health hazards of all the chemicals being used. Compliance with the storage and handling safeguards listed in the Material Safety Data Sheet of each chemical, needs to be accompanied by infrastructure changes. To reduce the health hazards of formaldehyde, institutions are taking appropriate countermeasures directed at the source itself, by using substitutes or injecting formaldehyde chelating agents, and are adopting high performance air extraction systems to protect the users. However, little is known about the flammability risk of embalmed human bodies. During a recent visit to McGill University morgue by architects and safety inspectors to expand it, we were asked about the flammability risk of the embalmed specimens, so we carried out a flashpoint test to evaluate the flammability potential of specimens embalmed with each of our three embalming techniques: formaldehyde-based, Thiel, and phenol-based. With the phenol-based embalming showing the most risks, attention should be drawn to all institutions who are experimenting with various embalming techniques to evaluate the flammability potential of their embalmed specimens.     

Toward safer thanatopraxy cares: formaldehyde‐releasers use

Human cadavers constitute very useful educational tools to teach anatomy in medical scholarship and related disciplines such as physiology, for example. However, as biological material, human body is subjected to decay. Thanatopraxy cares such as embalming have been developed to slow down and inhibit this decay, but the formula used for the preservation fluids are mainly formaldehyde (FA)‐based. Very recently, other formulas were developed in order to replace FA, and to avoid its toxicity leading to important environmental and professional exposure concerns. However, these alternative FA‐free fluids are still not validated or commercialized, and their efficiency is still under discussion. In this context, the use of FA‐releasing substances, already used in the cosmetics industry, may offer interesting alternatives in order to reduce professional exposures to FA. Simultaneously, the preservation of the body is still guaranteed by FA generated over time from FA‐releasers. The aim of this review is to revaluate the use of FA in thanatopraxy cares, to present its benefits and disadvantages, and finally to propose an alternative to reduce FA professional exposure during thanatopraxy cares thanks to FA‐releasers use.     

Impact of drying and thiel embalming on mechanical properties of achilles tendons

Biomechanical research and orthopedic training is regularly carried out on human cadavers. Given the post‐mortem decay, these cadavers were usually frozen or embalmed. The embalming method according to Dr. Thiel was often praised for the preservation of natural texture. The main aim of this article was to quantitatively analyze the impact of this embalming technique on the biomechanical properties. To that extent, Achilles tendons (calcaneal tendons) of seven cadavers have been tested. For each cadaver, a first tendon was tested following a fresh‐frozen conservation, the other following the Thiel embalming process. The results indicated a significant difference in Young's modulus between both groups (P values = 0.046). The secondary aim of this article was to analyze the impact of exposure to room conditions and associated dehydration on the biomechanical properties of cadaver tissue. Therefore, each tendon was tested before and after 2 hr of exposure to room conditions. The resulting dehydration caused a significant increase of the Young's modulus for the thawed fresh‐frozen tendons. The properties of the Thiel embalmed tendons were not significantly altered. In conclusion, this research promoted the use of fresh‐frozen specimens for biomechanical testing. Effort should, however, be made to minimize dehydration of the tested specimens. Clin. Anat. 28:994–1001, 2015. © 2015 Wiley Periodicals, Inc.     

Evaluation of methods to reduce formaldehyde levels of cadavers in the dissection laboratory

Dissection of conventionally embalmed cadavers exposes students, staff, and faculty to formaldehyde, a probable carcinogen. Therefore, prudent practices should seek to minimize formaldehyde exposure. In this study, we evaluated two commercially available chemicals, InfuTrace and Perfect Solution, for their effectiveness in reducing ambient formaldehyde levels. Four cadavers embalmed conventionally with formaldehyde and/or with the above agents were compared for their formaldehyde levels under conditions that strictly controlled for air circulation and for locations and methods of testing, and during activities that simulated student dissecting. For InfuTrace, one cadaver was reinfused with InfuTrace after initial standard perfusion with formaldehyde; a second cadaver had InfuTrace injected into the thoracic and abdominal body cavities after formaldehyde perfusion. For Perfect Solution, the product was used for embalming a third cadaver in lieu of formaldehyde. For a control, a fourth cadaver was embalmed with the standard formaldehyde solution. Testing of personal and ambient room air samples and of fluid obtained from the cadavers was performed and analyzed in a blinded fashion. Results indicated that both Perfect Solution, substituted for standard formaldehyde embalming, and InfuTrace infused through the vasculature after formaldehyde embalming, resulted in lower concentrations of formaldehyde than embalming with formaldehyde solution alone or in combination with body cavity injection of InfuTrace. These differences in formaldehyde concentrations are consistent across measuring methods, for example, of room air, of breathing zone air during cadaver handling and dissection, and of liquid samples obtained from the cadavers. Perfect Solution yielded suboptimum fixation and a different texture, color, and smell than the formaldehyde treatments.     

Assessing the effectiveness of 30% sodium chloride aqueous solution for the preservation of fixed anatomical specimens: a 5‐year follow‐up study

Anatomical specimens used in human or veterinary anatomy laboratories are usually prepared with formaldehyde (a cancerous and teratogenic substance), glycerin (an expensive and viscous fluid), or ethanol (which is flammable). This research aimed to verify the viability of an aqueous 30% sodium chloride solution for preservation of anatomical specimens previously fixed with formaldehyde. Anatomical specimens of ruminant, carnivorous, equine, swine and birds were used. All were previously fixed with an aqueous 20% formaldehyde solution and held for 7 days in a 10% aqueous solution of the same active ingredient. During the first phase of the experiment, small specimens of animal tissue previously fixed in formaldehyde were distributed in vials with different concentrations of formaldehyde, with or without 30% sodium chloride solution, a group containing only 30% sodium chloride, and a control group containing only water. During this phase, no contamination was observed in any specimen containing 30% sodium chloride solution, whether alone or in combination with different concentrations of formaldehyde. In the second phase of the experiment, the 30% sodium chloride solution, found to be optimal in the first phase of the experiment, was tested for its long‐term preservation properties. For a period of 5 years, the preserved specimens were evaluated three times a week for visual contamination, odors, and changes in color and texture. There was no visual contamination or decay found in any specimen. Furthermore, no strange odors, or changes in color or softness were noted. The 30% sodium chloride solution was determined to be effective in the preservation of anatomic specimens previously fixed in formaldehyde.     

Supplement to the conservation of an entire cadaver according to W. Thiel]

Ten years after publishing the method "The preservation of complete human cadavers in native colours" by W Thiel an improved variant, due to the experiences throughout this time, will be described for the general embalming of corpses and a relating to the apparatus establishment for the preservation of brain in situ.     

Elastic properties of Thiel‐embalmed human ankle tendon and ligament

Thiel embalming is recommended as an alternative to formalin‐based embalming because it preserves tissue elasticity, color, and flexibility in the long term, with low infection and toxicity risk. The degree to which Thiel embalming preserves elasticity has so far been assessed mainly by subjective scoring, with little quantitative verification. The aim of this study is to quantify the effect of Thiel embalming on the elastic properties of human ankle tendons and ligament. Biomechanical tensile tests were carried out on six Thiel‐embalmed samples each of the peroneus longus, peroneus brevis, and calcaneal tendons, and the calcaneofibular ligament, with strain rates of 0.25%s^?1, 2%s^?1, and 8%s^?1. The stress?strain relationship was calculated from the force‐extension response with cross‐sectional area and gauge length. Young's modulus was determined from the stress?strain curve. The results showed that the tendon and ligament elasticity were lower after Thiel embalming than the literature values for fresh nonembalmed tendons and ligament. The biomechanical tensile test showed that the measured elasticity of Thiel‐embalmed tendons and ligaments increased with the strain rate. The Thiel embalming method is useful for preserving human ankle tendons and ligaments for anatomy and surgery teaching and research, but users need to be aware of its softening effects. The method retains the mechanical strain rate effect on tendons and ligament. Clin. Anat. 28:917–924, 2015. © 2015 Wiley Periodicals, Inc.     

Freeze-dried specimens for gross anatomy teaching

As more and more emphasis is placed on the use of prosected specimens to support teaching and learning of gross anatomy, consideration must be given to developing new methods to preserve human cadaveric material, and in ways which will resist the wear and tear to which they are necessarily subjected. Taxidermists have developed techniques for freeze-drying whole small animals as a method of long term preservation (Metcalf, 1981). We have explored the use of this methodology to preserve small prosected specimens for use in the teaching of gross anatomy. The technique we report here was tested initially on larynges (Fig. 1) but has since been applied with equal success to other structures, including pieces of small intestine dissected to show the arterial arcades (Fig. 2). We have used material from cadavers which were preserved using our standard embalming procedure (O'Sullivan & Mitchell, 1993).     

遗体(尸体)防腐剂研究现状

本文对近年来国内外医学院校中尸体防腐及殡仪馆内遗体防腐剂研究现状进行了概述,重点介绍了防腐剂的作用机制;甲醛作为常用防腐剂的优缺点;新型防腐剂异噻唑啉酮类和离子液体的研究进展;改良的混合防腐液研究进展,并对遗体防腐剂研究提出了几点建议。     

Practical light embalming technique for use in the surgical fresh tissue dissection laboratory

Surgeons using a fresh tissue dissection laboratory need specimens with tissue color and texture as close as possible to those of a living body. Completely unembalmed specimens kept in a cooler remain in good condition only for a few days, and then decay rapidly. Unembalmed specimens can be frozen for later use, but freezing harms their texture, and decay is suspended only for as long as they remain frozen. Since 1998, we have used a method of light embalming adapted from funeral home techniques, on over 250 cadavers used in our fresh tissue dissection laboratory. Lightly embalmed cadavers can be kept in a cooler for up to 6 weeks before use, with negligible loss of tissue quality and color. Once dissection is begun, the cadavers remain in excellent condition, free from odor, for at least two further weeks. Light embalming overcomes the practical problems seen with completely unembalmed specimens, avoids the use of freezing, and extends the range of activities that can be planned in the laboratory. This paper presents details of the light embalming technique. We assume that light embalming does not kill all transmissible pathogens.     

The preservation of the whole corpse with natural color]

An especially low-odor embalming technique was developed over a 30-years-period using a total of 977 complete cadavers, numerous cadavers after autopsy, and in vitro series of fresh beef. The color, consistency, and transparency of the tissue were very well preserved. The technique met high standards of preservation without releasing harmful substances into the environment. Concentrations of formaldehyde in room air remained under the limit of detection by Dr?ger capillaries. The efficacy for disinfection of the method was confirmed by bacteriologic tests. None of the cadavers or samples developed molds.     

Formaldehyde exposure and its effects during pregnancy: Recommendations for laboratory attendance based on available data

Formalin is commonly used in fixation of cadaveric specimens. Exposure to formaldehyde, a component of formalin and a known carcinogen, during gross anatomy laboratory dissection is a continuing concern for pregnant students and instructors. Since there is little literature on this specific topic, the current review was compiled in the hope of offering recommendations to pregnant students and instructors who are engaged in human anatomical dissection where formalin is used. Relevant articles were obtained through searches of PubMed and Google Scholar for the terms “formaldehyde,” “pregnant,” “formalin,” and “exposure.” A literature search was conducted for chemical information and articles about exposure as issued by government regulatory agencies and chemical companies that produce formaldehyde. This led to the compilation of 29 articles each of which included references to previous, relevant, human research. The reviewed literature contains data strongly suggesting that pregnancy can be affected by formaldehyde exposure. Therefore, on the basis our analysis, female students who might be pregnant should avoid formaldehyde exposure, including that in a gross anatomy laboratory. Instructors should find other means of ensuring anatomical competence for these students. Clin. Anat. 28:972–979, 2015. © 2015 Wiley Periodicals, Inc.     

Thiel-embalming technique: investigation of possible modification in embalming tissue as evaluation model for radiofrequency ablation

Contrary to freezing preservation and formalin embalming, Thiel embalmed cadaver presents soft texture and color very close to that of living organism, and many applications based on Thiel embalmed cadavers have been reported. However, Thiel embalmed cadavers cannot be used as reliable evaluation model for radiofrequency ablation (RFA) due to dramatic changes of electrical conductivity in the embalmed tissue. To address this issue, we investigated various modifications of the original Thiel embalming solution. By altering the chemicals' species and concentration we figured out a formula that can greatly reduce the embalming fluid's electrical conductivity without significantly compromising the 18-day embalmed kidney samples' suppleness and color. We also investigated a two-stage embalming technique by first submerging the kidney sample into original Thiel's tank fluid for 28 days, then the sample was withdrawn from the tank fluid and placed into modified dilution fluids for additional two weeks. Stiffening and discoloration occurred in these diluted samples implying the reversibility of Thiel-embalmed tissues' suppleness and color with the removal of the strong electrolytes. This study presents a modified embalming method which could be used for RFA evaluation and also helps our understanding of the mechanism of embalmment process.     

Tissue biomechanics of the human head are altered by Thiel embalming,restricting its use for biomechanical validation

Thiel embalming is a well‐known method of anatomical fixation giving lifelike optical and haptic tissue properties. Beyond these characteristics, Thiel embalming may also be a promising method to provide lifelike tissues for validation purposes of human head biomechanics. Recent investigations using Thiel‐embalmed human tissues of the upper and lower limb yielded contradicting biomechanical results on fixation‐induced changes in the tissues' load‐deformation behavior. It is to date unclear if Thiel embalming may have a softening or stiffening effect on human soft tissues or no global effect on biomechanics compared to the fresh state, with the latter being the most desirable outcome. The given study aimed at assessing the effects of Thiel embalming on the uniaxial tensile properties of human head soft tissues. Age‐matched fresh and Thiel‐embalmed dura mater, temporalis muscle, temporalis muscle fascia, and scalp samples were examined. Dura, fascia, and scalp samples showed significantly different elastic moduli compared to fresh tissues (all P < 0.01). The observed ultimate tensile strength supports the theory of an increased collagen crosslinking of the embalmed tissues when compared to the fresh state. Thiel‐embalmed muscles failed any tensile testing approach as a result of the muscles dissolving due to the embalming. Furthermore, collagen integrity seems altered in scanning electron microscopy by the Thiel embalming, limiting their use for ultrastructural failure analyses. Thiel‐embalmed soft tissues may consequently not serve to reflect the biomechanical properties of the human head. Consequently, the application of Thiel embalming should be limited to preliminary tests for biomechanical purposes. Clin. Anat. 32:903–913, 2019. © 2019 Wiley Periodicals, Inc.     

A formalin fixative for immunochemical and ultrastructural studies on gastrointestinal endocrine cells.

Using indirect immunofluorescence, indirect immunoperoxidase, and unlabelled antibody enzyme techniques, gastrin, pancreatic glucagon, insulin, and somatostatin were localised in sections of both wax- and resin-embedded tissues that had been fixed in a buffered formalin solution. Ultrastructural preservation of the resin-embedded samples was also adequate for combined electron microscopy and light microscope immunochemistry. As the fixative concerned is stable it can be permanently available in surgical units. It is suggested, therefore, that this fixative should prove useful as an alternative to buffered formaldehyde, which must be freshly prepared from paraformaldehyde powder, in institutions where specimen collection is difficult or which have to refer cases with an endocrine involvement to other laboratories for immunochemical and fine structural examination.     

Rapid microwave fixation of human tissues for light microscopic immunoperoxidase identification of diagnostically useful antigens

Microwave (MW) energy permits rapid tissue fixation for light and electron microscopy but its effects on antigen preservation have not been fully evaluated. We, therefore, fixed three samples of human skin, uterus, and cervix, and two samples of human colon and breast by MW irradiation (5 to 8 seconds) during simultaneous immersion in a dilute aldehyde mixture (2% formaldehyde and 0.05% glutaraldehyde). For comparison, similar portions of each specimen were fixed in formalin. Specimens were processed routinely and embedded in paraffin for light microscopy. Sections from each specimen were stained with hematoxylin and eosin and, by immunoperoxidase techniques, for epithelial membrane antigen, leukocyte common antigen, S-100 keratin, carcinoembryonic antigen, and factor VIII-related antigen, the latter three with and without preliminary trypsinization. Colon sections were also stained for chromogranin. In all cases, light microscopic morphology was comparable for tissues fixed by the MW method and formalin-fixed specimens, as was immunostaining for epithelial membrane antigen, leukocyte common antigen, S-100 protein, and chromogranin. Formalin-fixed tissues required trypsinization for optimal detection of keratin, carcinoembryonic antigen, and factor VIII-related antigen. In contrast, trypsin-pretreatment was not necessary to demonstrate these antigens in MW-fixed specimens and, in fact, resulted in tissue digestion. We conclude that this MW fixation method provides a means for rapidly fixing tissues for immunoperoxidase staining while preserving excellent light microscopic morphology.     

UV-C Irradiation Reduces the Experimentally Induced Bacterial Load on the Surface of a Human Cadaver: An Additional Option for the Preservation of Cadavers in Anatomy

Safety is a major issue in the embalming procedures of human cadavers. Reduced application of formaldehyde is often recommended. The aim of this study was to investigate the potency of ultraviolet light (UV-C irradiation) on the bacterial load on the surface of a conserved human cadaver. To test UV-C irradiation, the cadaver was laid out in the dissection hall and, after preparation of the muscles, was covered with linen sheets moistened with water. Swabs of the surface and microbiological analysis revealed sporadic bacterial colonies. The surface area was then spiked with bacteria and irradiated by a UV lamp for 15 or 60 min. Half of the area was covered by aluminum foil to serve as a control. After exposition, swabs were taken and analyzed. The exposition had reduced the number of colonies to one third (15 min exposition) and to one tenth (60 min exposition) of the control area. Thus, UV-C irradiation could be used in the preservation of cadavers without chemical pollution of the environment and without any risk for the employees. Clin. Anat. 32:113–116, 2019. © 2019 The Authors. Clinical Anatomy published by Wiley Periodicals LLC on behalf of American Association of Clinical Anatomists.     

An improved low-formaldehyde embalming fluid to preserve cadavers for anatomy teaching

The desired properties required for successful embalming of cadavers for gross anatomy teaching include: (1) good long-term structural preservation of organs and tissues with minimal shrinkage or distortion; (2) prevention of over-hardening, while maintaining flexibility and suppleness of internal organs; (3) prevention of desiccation; (4) prevention of fungal or bacterial growth and spread within a specific cadaver and to other cadavers in the dissection room; (5) reduction of potential biohazards (spread of infection to dissection personnel and students); (6) reduction of environmental chemical hazards (especially from formaldehyde and phenol) in order to comply with increasingly severe health and safety regulations and a new awareness of possible dangers of these chemicals in the workplace; and (7) retention of colour of tissues and organs while minimising oxidation effects that result in 'browning'.