Qualitative and quantitative comparison of Thiel and phenol-based soft-embalmed cadavers for surgery training

Comparison of histological procedures and antigenicity of human post-mortem brains fixed with solutions used in gross anatomy laboratories

Background

Brain banks provide small tissue samples to researchers, while gross anatomy laboratories could provide larger samples, including complete brains to neuroscientists. However, they are preserved with solutions appropriate for gross-dissection, different from the classic neutral-buffered formalin (NBF) used in brain banks. Our previous work in mice showed that two gross-anatomy laboratory solutions, a saturated-salt-solution (SSS) and an alcohol-formaldehyde-solution (AFS), preserve antigenicity of the main cellular markers (neurons, astrocytes, microglia, and myelin). Our goal is now to compare the quality of histology and antigenicity preservation of human brains fixed with NBF by immersion (practice of brain banks) vs. those fixed with a SSS and an AFS by whole body perfusion, practice of gross-anatomy laboratories.

Methods

We used a convenience sample of 42 brains (31 males, 11 females; 25-90 years old) fixed with NBF (N = 12), SSS (N = 13), and AFS (N = 17). One cm3 tissue blocks were cut, cryoprotected, frozen and sliced into 40 μm sections. The four cell populations were labeled using immunohistochemistry (Neurons = neuronal-nuclei = NeuN, astrocytes = glial-fibrillary-acidic-protein = GFAP, microglia = ionized-calcium-binding-adaptor-molecule1 = Iba1 and oligodendrocytes = myelin-proteolipid-protein = PLP). We qualitatively assessed antigenicity and cell distribution, and compared the ease of manipulation of the sections, the microscopic tissue quality, and the quality of common histochemical stains (e.g., Cresyl violet, Luxol fast blue, etc.) across solutions.

Results

Sections of SSS-fixed brains were more difficult to manipulate and showed poorer tissue quality than those from brains fixed with the other solutions. The four antigens were preserved, and cell labeling was more often homogeneous in AFS-fixed specimens. NeuN and GFAP were not always present in NBF and SSS samples. Some antigens were heterogeneously distributed in some specimens, independently of the fixative, but an antigen retrieval protocol successfully recovered them. Finally, the histochemical stains were of sufficient quality regardless of the fixative, although neurons were more often paler in SSS-fixed specimens.

Conclusion

Antigenicity was preserved in human brains fixed with solutions used in human gross-anatomy (albeit the poorer quality of SSS-fixed specimens). For some specific variables, histology quality was superior in AFS-fixed brains. Furthermore, we show the feasibility of frequently used histochemical stains. These results are promising for neuroscientists interested in using brain specimens from anatomy laboratories.

Novel teaching-learning and assessment tools to complement competency-based medical education in postgraduate training

Medical and educational techniques and approaches have evolved globally over the past few decades. The modern approach is more learner-centred, with a focus on the acquisition of skills. The recently implemented competency-based medical education (CBME) for the National Medical Commission (NMC) undergraduate course curriculum is also competency-based rather than an outcome-based traditional curriculum. It is vital to embrace innovative teaching-learning and educational strategies to achieve the aspiration of CBME. This article provides a list of some of the newer tools and their perceived advantages and challenges and serves as a guide for using these methods effectively to meet the objectives of CBME as proposed by the NMC. Virtual teaching, learning from digital resources, objective-structured practical and clinical examination, flipped classroom, case-based learning, serious gaming, simulation-based learning and learning from role-plays and portfolios emerged as novel instructional strategies.

Current and potential use of fresh frozen cadaver in surgical training and anatomical education

As surgical procedures continue to be more complex, the need for more effective training in anatomy has increased. The study of anatomy plays a significant role in the understanding of the human body as well as in basic and advanced clinical training. Among the different cadaver models, fresh frozen cadavers (FFCs) are known for their realistic tissue quality. The purpose of this article was to review and summarize the preparation procedures for and reported cases involving FFCs. PubMed, Scopus, Medline, and Web of Science were searched for relevant studies. The preparation procedures were divided into five steps: washing, irrigation, freezing, defrosting, and arterial infusion. Not all steps were reported to be mandatory, but omitting one or more could result in a loss of quality. FFCs were reported to be used for various purposes: undergraduate education, general surgery training, vascular surgery training, minimal access surgery (laparoscopic surgery) training, and microsurgery training. In all categories, expert opinions and statistical analyses indicated successful outcomes. The reasons for high satisfaction with FFCs included realistic texture, capability of reenacting actual operations, and accuracy of anatomical locations. The results also revealed the importance and advantages of the dissection courses in surgical training. Since the direct comparison between cadaver models is insufficient, future studies regarding this topic are deemed necessary. In addition, it would be advantageous to develop methods to improve FFC quality, or ideas to optimize this model for certain purposes.

Efficacy of urea solution reperfusion to a formalin-embalmed cadaver for surgical skills training

Formaldehyde has been traditionally used for embalming human cadavers for gross anatomy education and surgical skills training. However, exposure to formaldehyde negatively affects human health. This study aimed to assess the efficacy of reperfusing urea solution to a formalin-embalmed cadaver for surgical skills training and then investigate the cadaver's tissue elasticity alteration after being soaked into the urea solution. Twelve surgeons evaluated the similarity of tissue characteristics between the cadaver (embalmed by formalin solution and reperfused by urea solution) and a living human body. Furthermore, the tissue formaldehyde content and mechanical properties of the formalin-fixated femoral skin and artery specimens with or without soaking into urea solution were measured. Results showed that the tactile assessment, skin incision, vessel ligation and suture, and decollement were better and more useful in the cadaver reperfused by urea solution than in the cadaver merely fixated by formalin solution. In the urea-reperfused cadaver, the volatilized, or tissue formaldehyde levels declined. The stiffness and Young's modulus of the femoral skin and artery were also lower in the specimen than in the mere formalin-fixated specimen. In conclusion, reperfusion of urea solution to the formalin-fixated cadaver makes anatomical education and surgical skills training more efficient with fewer requirements for cadaver management.

10 tips on working with human body donors in medical training and research

Human body donors selflessly decided to make the ultimate gift to donate their bodies to education. Being on the receiving end, the health sciences education community owes it to the donors to ensure that they are being treated with utmost respect by promoting and developing high ethical standards and maximizing the benefits from this gift. Working with human body donors for research purposes has increased over the years, while regulations associated with these processes did not change. This article draws upon current literature and author’s experiences to offer practical tips for health educators and everyone working with body donors to achieve these goals. We offer 10 practical tips that help in starting the conversation about the best ways to work with body donors to maximize their contribution to health sciences education.

A Novel Cadaveric Embalming Technique for Enhancing Visualisation of Human Anatomy

Within the discipline of anatomical education, the use of donated human cadavers in laboratory-based learning activities is often described as the 'gold standard' resource for supporting student understanding of anatomy. Due to both historical and educational factors, cadaveric dissection has traditionally been the approach against which other anatomy learning modalities and resources have been judged. To prepare human donors for teaching purposes, bodies must be embalmed with fixative agents to preserve the tissues. Embalmed cadavers can then be dissected by students or can be prosected or plastinated to produce teaching resources. Here, we describe the history of cadaveric preservation in anatomy education and review the practical strengths and limitations of current approaches for the embalming of human bodies. Furthermore, we investigate the pedagogic benefits of a range of established modern embalming techniques. We describe relevant cadaveric attributes and their impacts on learning, including the importance of colour, texture, smell, and joint mobility. We also explore the emotional and humanistic elements of the use of human donors in anatomy education, and the relative impact of these factors when alternative types of embalming process are performed. Based on these underpinnings, we provide a technical description of our modern Newcastle-WhitWell embalming process. In doing so, we aim to inform anatomy educators and technical staff seeking to embalm human donors rapidly and safely and at reduced costs, while enhancing visual and haptic tissue characteristics. We propose that our technique has logistical and pedagogic implications, both for the development of embalming techniques and for student visualisation and learning.

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.

Comparison of suturing models: the effect on perception of basic surgical skills

BACKGROUND

Acquisition of Basic Surgical Skills (BSS) are essential for medical students. The objective was to determine it's fidelity impact.

METHODS

Using four suturing models (SM) (pigskin, sponge, commercial pad, and orange), SM-quality and student-SM interaction were evaluated. After a 1-h class, participants were divided into groups and randomly assigned exercises in SM in 15-min intervals. The experiment included completing three individual simple stitches and a 3-stitch continuous suture in each SM.

RESULTS

Eighty-two medical students participated. Suturing quality was better in pigskin and sponge, which were also the preferred models (p < 0.001). Significant differences in quality between the insertion and exit point, and firmness of knots (p < 0.05) in both simple and continuous sutures, as well as between length and distance in continuous ones (p < 0.001) were identified.

CONCLUSIONS

Acquisition and quality of BSS are influenced by the intrinsic characteristics of SM. An adequate degree of resistance, consistency, and elasticity are necessary.