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

Analysis of the learning curve for unilateral biportal endoscopic technique using CUSUM method on fresh frozen cadavers

PURPOSE

This study aims to determine the learning curve for lumbar discectomy and nerve root decompression using the unilateral biportal endoscopic (UBE) technique on fresh frozen cadavers through linear regression and cumulative sum (CUSUM) analyses.

METHODS

The analysis was conducted on three spine surgeons without UBE experience. They performed lumbar discectomy using the unilateral endoscopic technique on fresh frozen cadavers. Each physician performed operations on 40 lumbar spine segments, recording the time it took each physician to complete a segment of lumbar discectomy by UBE. The learning curve was assessed by linear regression and CUSUM analysis using SPSS 27.0 software and GraphPad Prism 8.0 software.

RESULTS

According to the CUSUM analysis of the learning curve, the number of segments required to complete the learning phase for the three surgeons was 20, 16, and 20, respectively. With the increased number of operated segments, the operation time for each lumbar vertebral segment gradually decreased and stabilized.

CONCLUSIONS

In our study, spine surgeons without experience in UBE require 20 segments of surgery to overcome the UBE learning curve. Additionally, fresh frozen cadavers can effectively simulate real surgeries. Whenever possible, we should reasonably use fresh frozen cadavers for early UBE training of doctors, thereby better protecting the health and safety of patients.

Proposal for a uniform protocol and checklist for cadaveric courses for surgeons with special interest in open abdominal wall reconstruction

PURPOSE

Over the last decade, there has been a rapid rise in the development and refinement of abdominal wall repair (AWR) techniques. Numerous cadaveric AWR training courses have been set up with the goal of helping practicing surgeons learn and incorporate them into their surgical repertoire. Some maybe excellent but their quality and consistency are unknown. The aim of this article is to present a stepwise cadaveric dissection template and checklist to standardize all training on open AWR courses and to help course organizers benchmark the quality of their program.

METHODS

This article is based on both the authors experience as faculty and course leads of cadaveric AWR courses, and the published anatomical and operative literature. The authors represent the training committee of the European Hernia Society, and the AWR subcommittees of the British Hernia Society and Association of Coloproctology of Great Britain & Ireland.

RESULTS

A standardized stepwise approach for the cadaveric training of the most recognized procedures for open AWR, including retrorectus repair, posterior and anterior component separation techniques, is presented. Considerations on delegate selection, pre-course material and testing, course structure, and cadaveric models is also provided.

CONCLUSION

Time and financial resources for surgeons to attend courses to learn and hone the skills required for safe effective AWR is limited. Ideally all courses should deliver up to date consistent training of the highest quality. One step to achieve this is by developing a standardized approach to ensure delegate understanding of the operative steps and key anatomical features.

Critical appraisal of Genelyn soft embalming for cadaveric surgical skill training: A systematic review

Genelyn is a proprietary embalming solution used for preserving cadavers for surgical skill training (SST) and undergraduate teaching. The aim of this review is to examine the Genelyn embalming method critically by analyzing scientific publications that have employed this method for SST and undergraduate education. The systematic review process involved searching for all relevant articles in PubMed, Google Scholar, and Embase using the keywords "Genelyn," Genelyn embalming," "Genelyn embalmed cadaver," and "surgical skill training. All studies on Genelyn embalming published up to August 14, 2024, in the English language were eligible for inclusion. The literature review yielded 92 studies, 43 of which met the inclusion criteria. The Anatomical Quality Assurance (AQUA) tool from the International Evidence-Based Anatomy (iEBA) working group was used to assess and analyze the risk of bias in all the selected full-text articles. The selected studies reported that Genelyn embalming provided life-like joint range of motion, tissue pliability, and color. Cadaveric studies assessing embalming solutions typically had smaller sample sizes, and few of them compared Genelyn embalmed cadavers (GECs) with the other soft embalming solutions. Unlike Theil's embalming, Genelyn embalming is cost-effective, with easy steps for the preparation and storage of the solution and convenient handling of cadavers. Therefore, GECs serve as an efficient tool for SSTs.

Efficacy of fresh-frozen cadaveric surgical training for arteriovenous fistula in vascular access

BACKGROUND

Creation of an arteriovenous fistula (AVF) as vascular access is a basic operation that should be learned by all surgeons involved in renal failure treatment. AVF creation is often challenging for inexperienced young surgeons because it requires comprehensive surgical techniques. For such young surgeons, we introduced cadaveric surgical training (CST) for AVF creation using fresh-frozen cadavers (FFCs). This study was performed to identify the differences in AVF surgical techniques between FFCs and living bodies and to examine the impact of CST on young surgeons.

METHODS

Twelve CST sessions were performed for AVF creation at the Clinical Anatomy Education and Research Center of Tokushima University Hospital from March 2021 to June 2022. Seven young surgeons (1st- and 2nd-year) performed the operation, and two surgeons (10th- and 11th-year) supervised it. We conducted an anonymous questionnaire survey using a 5-point Likert scale to examine the impact of CST on young surgeons.

RESULTS

Twelve CST sessions were performed on nine FFCs. All training sessions allowed completion of AVF creation with a median operative time of 78.5 min. Although veins and arteries were more difficult to identify than in a living body, other surgical operations could be performed in the same way as in a living body. All the respondents stated that it was good for them to experience CST. In addition, 86% of surgeons responded that CST improved their surgical techniques, and 71% of surgeons responded that they were less anxious about AVF creation.

CONCLUSIONS

CST for AVF creation is useful for surgical education because it enables learning of surgical techniques that are almost equivalent to those in living bodies. In addition, this study suggested that CST not only contributes to the improvement of surgical skills of young surgeons but also promotes the reduction of anxiety and stress about AVF creation.

Surface anatomy and levator scapulae muscle injection: A cadaveric investigation

Accurate detection of the levator scapulae muscle is critical for effective diagnostic and therapeutic interventions. The commonly used surface anatomy approach has not been validated and is less accurate than ultrasound-guided techniques. Therefore, we determined the needle insertion point for the levator scapulae using a new technique based on the anatomy of the scapula. This investigation used 15 fresh-frozen cadavers to explore the relationship between the acromial angle and medial tip of the scapular spine (O) of the scapular spine. Based on the x-axis (the distance [L] from Point O to point acromial angle) and the y-axis perpendicular to the x-axis passing through Point O, the barycentric coordinates were determined through the intersections of each axis and the superior angle of the scapula with the levator scapulae. Various ratios involving the established distance L) were ascertained, we compared the measurements and ratios between the male and female groups, and the accuracy of the new technique was compared with the conventional technique. The optimal site of the new technique was within 6 to 7% of distance L on the x-axis and 42 to 44% of distance L on the y-axis. This technique was significantly more accurate than the conventional technique (P = .006). Although ultrasound allows for accurate injections via real-time visualization, its unavailability in some cases highlights the importance of understanding surface anatomy landmarks. Our new technique, based on the anatomy of the scapula and relative measurements, is more accurate than the conventional technique. This should enable more precise detection of the levator scapulae for accurate and efficient diagnostic and therapeutic procedures.

A Bibliometric Analysis of Publications on Cadavers: A Study Based on Web of Science Data From 1978 to 2023

This study aimed to investigate the significance of publications examining the effectiveness of cadaver studies in the field of medicine with the method of bibliometric analysis, which emerged in the 1950s, offers the opportunity to conduct a detailed analysis of a specific subject, just like a systematic literature review or meta-analysis. Also, it aimed to enlighten the content of cadaver studies in the last half-century and to present a perspective for the future. In the study, an advanced search was conducted on the Web of Science Core Collection database on August 1, 2023, using the keywords "cadaver," "cadaver study," "cadaveric dissection." Review articles were excluded from the study. There were determined 34554 documents. The documents were transferred to the VOSviewer software program. In this way, the authors made detailed analyses of authors, keywords, journals, organizations, institutions, and countries and created scientific maps. The United States was one of the most important countries in terms of research. Generally, the use of cadaver terms in documents belongs to surgery, anatomy, and transplantation journals. Anatomy, cadaver, biomechanics, ultrasound, and computed tomography were the top 5 most frequently used keywords with cadaver term. The findings of our study showed that cadaver studies are used in many fields of medical science. However, clinical studies, including advanced imaging techniques, draw attention to the developing technology. Along with the powerful institutions of the United States, its great contributions to publications stand out.

A response to a single cadaver study assessing the efficacy of two commercially available devices for airway foreign body relief

A review of the speculative conclusions and poor methodology in assessing the efficacy of the LifeVac airway clearance device.

Video-stylet vs. channeled hyperangulated videolaryngoscope: Efficacy in simulated Ludwig's angina randomized cadaver trial

INTRODUCTION

Ludwig's angina (LA) is a life-threatening infection that can affect the floor of the mouth and neck, potentially causing serious airway obstruction. In such cases, rescue airway management and oxygenation can be challenging due to swelling of the mouth floor, trismus, and limited mouth opening. The aim of this study was to assess the efficacy of the Trachway video-stylet (VS) and Pentax AWS hyperangulated videolaryngoscope with channel (HAVL-C) compared to the standard geometric video-laryngoscope (SGVL, Macintosh 3, Trachway) in simulating Ludwig's angina with cadavers.

METHODS

Three fresh frozen cadavers were prepared with varying degrees of difficulty to simulate the airway conditions of patients with LA, including mouth floor swelling, restricted mouth opening, and trismus. Fifty-five second-year resident physicians from various specialties participated in the study and received training in airway management using SGVL, VS, and HAVL-C devices. Participants were randomly assigned to intubate simulated LA with cadavers using the three devices in a random order, and intubation times and success rates were recorded. Participants also rated the difficulty of intubation using a visual analogue scale (VAS) score. The primary outcome assessed the first-pass intubation success or failure, while the secondary outcomes measured the intubation time and subjective difficulty using a visual analogue scale with different laryngoscopes.

RESULTS

The success rates for intubation within 90 s were 40% for SGVL, 82% for VS, and 76% for HAVL-C. VS and HAVL-C had significantly higher success rates than SGVL, with hazard ratios of 3.4 and 2.7, and 95% confidence intervals (CI) of 2.0-5.7 and 1.6-4.6, p < 0.001, respectively. The odds ratios of successful intubation for VS and HAVL-C were 8.1 and 6.3, respectively, with a 95% CI of 3.7-17.8 and 2.4-16.7, p < 0.001, compared to SGVL. The VAS score was significantly correlated with intubation success rate and time.

CONCLUSIONS

In cases of LA, the use of VS and HAVL-C is preferable over SGVL. These findings suggest that using VS and HAVL-C can improve intubation success rates and reduce intubation time in patients with LA.

The importance of laparoscopic surgery for young urologists remains unwavering even in the era of robot-assisted surgery

Robot-assisted surgery (RAS) cannot be achieved without the performance of laparoscopic surgical techniques by a patient-side surgeon (PSS). In many medical institutions in Japan, young urologists often take on the role of a PSS. Participating in RAS as a PSS provides a good opportunity to acquire not only the knowledge necessary for surgery, but also skills in laparoscopic surgical techniques. Learning laparoscopic surgery as a PSS may contribute to improving the quality of RAS. Furthermore, it will lead to skill improvement as an operator in laparoscopic surgery. However, notably, opportunities for young urologists to perform laparoscopic surgery are decreasing in the current era of RAS. Under these circumstances, we believe that cadaver surgical training will become increasingly important in the future. We believe that performance of cadaver surgical training will contribute to increased motivation, enhance the understanding of surgical procedures, and facilitate the acquisition of surgical techniques.

Undergraduate medical student perceptions and learning outcomes related to anatomy training using Thiel- and ethanol-glycerin-embalmed tissues

Anatomical dissection is known to serve as an integral tool in teaching gross anatomy, including postgraduate training. A variety of embalming techniques exist, resulting in different haptic and optical tissue properties. This study aimed to objectify learning outcomes and medical student perceptions related to the use of two widely used embalming techniques, namely Thiel and ethanol-glycerin embalming. Between 2020 and 2022, first- and second-year medical students enrolled in the course on topographic anatomy participated in this study. Objective structured practical examinations were carried out for the head, neck, thorax, abdomen, pelvis, and extremity regions following regional dissection just before the oral examinations began. Six to ten numbered tags were marked in prosections of each region in Thiel- and ethanol-glycerin-embalmed specimens. Following the examinations, the students were surveyed regarding the suitability of the two embalming techniques with respect to preservation, colorfastness, tissue pliability, and the suitability in preparing for their anatomy examinations. Consistently higher scores were achieved for the thoracic and abdominal regions in ethanol-glycerin-embalmed specimens when compared to Thiel. No benefit was found for Thiel-embalmed upper or lower extremities. Tissues embalmed with ethanol-glycerin were rated higher for preservation and suitability to achieve the learning objectives, tissue pliability was rated higher for Thiel-embalmed tissues. Ethanol-glycerin embalming appears to offer certain advantages for undergraduate students in recognizing visceral structures, which may align with students' ideas on tissue suitability for their learning. Consequently, the benefits reported for Thiel embalming for postgraduate study unlikely reflect its suitability for novices.

High-Fidelity Perforator Visualization for Cadaver Dissection in Surgical Training

In the first half of the third century B.C., Herophilus and Erasistratus performed the first systematic dissection of the human body. For subsequent centuries, these cadaveric dissections were key to the advancement of anatomical knowledge and surgical techniques. To this day, despite various instructional methods, cadaver dissection remained the best way for surgical training. To improve the quality of education and research through cadaveric dissection, our institution has developed a unique method of perforator-preserving cadaver injection, allowing us to achieve high-fidelity perforator visualization for dissection studies, at low cost and high efficacy. Ten full body cadavers were sectioned through the base of neck, bilateral shoulder, and hip joints. The key was to dissect multiple perfusing arteries and draining veins for each section, to increase "capture" of vascular territories. The vessels were carefully flushed, insufflated, and then filled with latex dye. Our injection dye comprised of liquid latex, formalin, and acrylic paint in the ratio of 1:2:1. Different endpoints were used to assess adequacy of injection, such as reconstitution of eyeball volume, skin turgor, visible dye in subcutaneous veins, and seepage of dye through stab incisions in digital pulps. Dissections demonstrated the effectiveness of the dye, outlining even the small osseous perforators of the medial femoral condyle flap and subconjunctival plexuses. Our technique emphasized atraumatic preparation, recreation of luminal space through insufflation, and finally careful injection of latex dye with adequate curing. This has allowed high-fidelity perforator visualization for dissection studies.

The efficacy of two commercially available devices for airway foreign body relief: A cadaver study

Objective

Foreign body aspiration events are frequent in young children and in the geriatric population. They may result in several complications such as hypoxia, edema, cardiac arrest, and death. Recently, two commercially available devices, the LifeVac and DeChoker, have entered the market with the claim of relieving foreign body aspiration. Both devices are portable, nonpowered, suction devices that are being considered for use in large public spaces such as schools, airports, and malls despite previous studies detailing variable efficacy. In this study, we aim to contribute further data on the safety and efficacy of these devices through a fresh cadaver model.

Methods

Commonly aspirated foods of three different sizes (saltines, grapes, and cashews) were placed at the level of the true vocal folds in a fresh cadaver. Three participants performed two trials with each food and device. Device use was performed to manufacturer specifications.

Results

The DeChoker resulted in gross injury to the tongue and failed to remove the obstruction in all trials. LifeVac was successful in removing the barium-moistened saltines but failed to remove all other foreign bodies. Both devices applied significant pressure to the tongue.

Conclusion

With the exception of the LifeVac removing saltine crackers, all trials were entirely unsuccessful in relieving foreign body aspiration. Additionally, both devices may cause significant pressure and injury to the oral cavity in a clinical setting. We conclude bystanders should continue to follow International Liaison Committee on Resuscitation's guidelines on resuscitation to aid with relieving foreign body aspiration.

Level of Evidence

4.

The Third Dimension: 3D Printed Replicas and Other Alternatives to Cadaver-Based Learning

Capturing the 'third dimension' of complex human form or anatomy has been an objective of artists and anatomists from the renaissance in the fifteenth and sixteenth centuries onwards. Many of these drawings, paintings, and sculptures have had a profound influence on medical teaching and the learning resources we took for granted until around 40 years ago. Since then, the teaching of human anatomy has undergone significant change, especially in respect of the technologies available to augment or replace traditional cadaver-based dissection instruction. Whilst resources such as atlases, wall charts, plastic models, and images from the Internet have been around for many decades, institutions looking to reduce the reliance on dissection-based teaching in medical or health professional training programmes have in more recent times increasingly had access to a range of other options for classroom-based instruction. These include digital resources and software programmes and plastinated specimens, although the latter come with a range of ethical and cost considerations. However, the urge to recapitulate the 'third dimension' of anatomy has seen the recent advent of novel resources in the form of 3D printed replicas. These 3D printed replicas of normal human anatomy dissections are based on a combination of radiographic imaging and surface scanning that captures critical 3D anatomical information. The final 3D files can either be augmented with false colour or made to closely resemble traditional prosections prior to printing. This chapter details the journey we and others have taken in the search for the 'third dimension'. The future of a haptically identical, anatomically accurate replica of human cadaver specimens for surgical and medical training is nearly upon us. Indeed, the need for hard copy replicas may eventually be superseded by the opportunities afforded by virtual reality (VR) and augmented reality (AR).

The use of a surgical boot camp combining anatomical education and surgical simulation for internship preparedness among senior medical students

BACKGROUND

Senior medical students feel unprepared for surgical procedures and care for surgery patients when they begin their internship. This study sought to introduce and evaluate a surgical boot camp training for senior medical students.

METHODS

A 44-h surgical boot camp program of lectures on clinical practice simulation, anatomical dissections, and simulated operation on cadavers was designed, implemented, and evaluated during the 2018 to 2019 academic year. A self-administered questionnaire was used to assess students' perceptions of the content, delivery, and self-confidence. The mini-Clinical Evaluation Exercise (mini-CEX) and the Operative Performance Rating System were used to assess skills essential to good clinical care and to facilitate feedback.

RESULTS

Over 93% of the students were satisfied with the surgical boot camp, training equipment, and learning materials provided. After six sessions of training, 85.3% reported gaining self-confidence and performed better in some surgical procedures such as major gastrectomy. The mini-CEX scores suggested significant improvement in the students' clinical skills, attitudes, and behaviors (P < 0.01). Ninety-eight percent of students felt that the anatomical knowledge taught met their needs. The scores of the Operative Performance Rating System suggested that the students' surgical skills such as instruments handling, incising, treatment of surrounding tissues (blood vessels, nerves), and smoothness of the whole operation had increased significantly following the surgical boot camp (All P < 0.01).

CONCLUSION

The surgical boot camp curriculum improved students' satisfaction and confidence in core clinical practice competencies. Therefore, medical schools the world over should continue to seek ways to bridge the gaps between pre-clinical, clinical, and internship training.

Morphological and Immunopathological Aspects of Lingual Tissues in COVID-19

COVID-19, a recently emerged disease caused by SARS-CoV-2 infection, can present with different degrees of severity and a large variety of signs and symptoms. The oral manifestations of COVID-19 often involve the tongue, with loss of taste being one of the most common symptoms of the disease. This study aimed to detect SARS-CoV-2 RNA and assess possible morphological and immunopathological alterations in the lingual tissue of patients who died with a history of SARS-CoV-2 infection. Sixteen cadavers from 8 SARS-CoV-2 positive (COVID-19+) and 8 negative (COVID-19−) subjects provided 16 tongues, that were biopsied. Samples underwent molecular analysis through Real-Time RT-PCR for the detection of SARS-CoV-2 RNA. Lingual papillae were harvested and processed for histological analysis and for immunohistochemical evaluation for ACE2, IFN-γ and factor VIII. Real-Time RT-PCR revealed the presence of SARS-CoV-2 RNA in filiform, foliate, and circumvallate papillae in 6 out of 8 COVID-19+ subjects while all COVID-19− samples resulted negative. Histology showed a severe inflammation of COVID-19+ papillae with destruction of the taste buds. ACE2 and IFN-γ resulted downregulated in COVID-19+ and no differences were evidenced for factor VIII between the two groups. The virus was detectable in most COVID-19+ tongues. An inflammatory damage to the lingual papillae, putatively mediated by ACE2 and IFN-γ in tongues from COVID-19+ cadavers, was observed. Further investigations are needed to confirm these findings and deepen the association between taste disorders and inflammation in SARS-CoV-2 infection.

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.