A comparison of embalming fluids for use in surgical workshops

A comparison of 1- versus 3-month regional anatomy exposure on learning outcomes of undergraduate medical students

Regional anatomy teaching forms a cornerstone of undergraduate medical education. Owing to an increase in teaching and learning content throughout the medical curriculum in recent years, contact hours and overall course durations in anatomy are under review worldwide. This study aimed to assess whether shortening the course content duration impacts learning gain and the ability to identify anatomical structures correctly. Undergraduate medical students of the Johannes Kepler University Linz (JKU; n = 310) and at the Medical University of Graz (MUG; n = 156) participating in regional anatomy courses were included. Whole body regional anatomy courses, including hands-on dissection and accompanying lectures, were delivered over one or three months. Course content and examination mode were kept consistent, while the duration of knowledge delivery was one or three months, respectively. Objective structured practical examinations (OSPE) were then carried out on prosections for the neck, thorax, and abdomen. 3-month course exposure resulted in significantly higher OSPE scores for the neck (49 vs. 37%), thorax (65 vs. 54%), and abdomen (65 vs. 45%), respectively. Further evaluation of the utility of different embalming types yielded higher 3-month scores in the neck and thorax regions with Thiel-embalmed tissues and thorax and abdomen regions in ethanol-glycerin-embalmed tissues. Course exposure over a more extended period, like three months, appears to be highly beneficial.

Cadaver preservative properties of a solution composed of honey, ethyl alcohol, liquid paraffin, distilled water and citric acid: Experiments on rabbit cadavers

The objective of this study is to assess the efficacy of a solution including honey, ethyl alcohol, liquid paraffin, distilled water and citric acid (HEFS) as a preservative for rabbit cadavers, serving as a potential substitute for formaldehyde. The cadavers underwent preservation using three distinct solutions: 10% formalin, 35% alcohol and HEFS. The cadavers were subjected to a total of four sampling events, occurring at 4-month intervals, in order to collect specimens for microanatomical, histological, microbiological, mycological, colourimetric, texture and odour analysis. In terms of hardness, suitability for dissection and joint mobility metrics, the cadavers fixed with HEFS had superior qualities to those fixed with formalin. The fixation quality of HEFS for histological analyses was deemed acceptable, except kidney and intestinal tissues. In texture analysis, differences only in the elasticity parameter (p < 0.05) in the same sampling period. A total of 10 (13.9) bacteria isolates were identified among which, Metasolibacillus meyeri 3 (30%) was predominantly followed by Staphylococcus aureus 2 (20%), Bacillus siamensis, Bacillus subtilis, Pseudarthrobacter oxydans, Bacillus licheniformis, Bacillus subtilis subsp. subtilis with a proportion of 1 (10%), respectively, by both microbiological and molecular analysis. However, no anaerobic bacteria and fungi were isolated. A considerable percentage of the students had the perception that HEFS was appropriate for utilization in laboratory settings due to its absence of unpleasant odours and detrimental impact on ocular and respiratory functions. In conclusion, we consider that HEFS may serve as a viable substitute for formalin solution in the preservation of rabbit cadavers.

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.

A novel model for hands-on laparoscopic pelvic surgery training on Genelyn-embalmed body: an initial feasibility study

The human donor body provides a well-accepted ex vivo model for laparoscopic surgical training. Unembalmed, or fresh-frozen, bodies comprise high-fidelity models. However, their short life span and high cost relatively limit the hands-on training benefits. In contrast, soft embalmed body of donors has a relatively longer usability without compromising tissue flexibility. This study reports the initial experience of the utility and feasibility of human donor Genelyn-embalmed body as a novel soft-embalmed cadaveric model for laparoscopic surgical training. An expert laparoscopic surgeon, who organised many fresh-frozen body donor courses, performed deep laparoscopic pelvic dissection and laparoscopic surgical tasks including suturing and electrosurgery on a single Genelyn-embalmed body. The three sessions were performed over a course of 3 weeks. The body was fully embalmed using the Genelyn technique. The technique consisted of a single-point closed arterial perfusion of embalming solution via the carotid artery with no further exposure to or immersion in embalming fluids thereafter. The donor's Genelyn-embalmed body provided a feasible model for laparoscopic surgical training. Initial experience shows evidence of this model being feasible and realistic. There was reproducibility of these qualities across a minimum of 3 weeks in this single-donor study. Initial experience shows that donor's Genelyn-embalmed body provides a novel model for laparoscopic surgical training, which possesses fidelity and is feasible for laparoscopic training. While further studies are needed to validate these findings, this technical note provides perspectives from an expert trainer regarding this model and provides a photographic and videographic atlas of this model's use in laparoscopy.

Simulation of Reconstructive Microsurgery in Soft Embalmed Cadavers: A Teaching Module for Plastic Surgery Residents

Background  Cadaveric dissection courses—comprising flap harvesting techniques, vessel dissections, flap transfers to the defect, and microvascular anastomosis—would help residents gain confidence and master these difficult major reconstructive microsurgery procedures. Formalin embalmed bodies lack natural softness and many other features of a live body. Many soft embalming techniques have evolved to mimic live tissue and Theil technique is the most popular one among them. We explored alternate soft embalming options and started using Genelyn.

Materials and Methods  Over a span of 2 years (2019–2021), we have conducted three flap dissection workshops using soft-embalmed cadavers. Six soft-embalmed and two formalin-embalmed cadavers were used. Total number of participants was 80.

Results  Feedback of experience from the third course participants in the form of grades (1–5) for different criteria was obtained and evaluated. Confidence in the dissection of the various flaps and microsurgery is noticeable in all the participants.

Conclusion  Based on our experience, we propose that flap dissection and microsurgery training on soft-embalmed cadavers be included as a teaching module in the plastic surgery postgraduate curriculum.

Evaluation of formaldehyde exposure among gross dissection after modified embalming solution and health assessment

Mainly embalming fixative contains formaldehyde which is classified as a carcinogen. People who work with cadavers have been at higher risk of cancer after formaldehyde exposure. We have formulated a less-formalin fixative (contained 3.6% formaldehyde,23.8% ethanol, 15% glycerin, and 0.2% phenol in the water) for preserving cadavers. Therefore, the objective of the present study was to evaluate the level of atmospheric formaldehyde indoors and the breathing exposure of medical students during dissection classes. We also analyzed the pulmonary parameters and effects of formaldehyde. The levels of atmospheric formaldehyde indoors and personal breathing exposure were sampled during anatomy dissection classes (musculoskeletal system, respiratory system, and abdominopelvic organ system) using sorbent tubes with air sampling pumps. Samples were then analyzed using Gas Chromatography with Flame Ionization Detector (GC-FID). The mean level of formaldehyde indoor air among the three classes was 0.518 ± 0.156 ppm whereas the formaldehyde level in the personal breathing zone was 0.956±0.408 ppm, which exceeded the recommended exposure standards of international agencies, including NIOSH agency and PEL of Thailand legislation. The laboratory had high humidity, high room temperature, and poor air ventilation. There was a significant difference in FVC, FEV1, and PEF (p < 0.05) between the sexes of students. Comparison pulmonary parameters between students and instructors showed that all parameters of the pulmonary function test had no significant differences. General fatigue and burnings of eyes and nose associated with strong odor were the most common symptoms reported during the dissection classes. The modified embalming fixative was used less formalin with ethanol-glycerin mixture, and it was suitable for the study of medical students, with few side effects of respiratory problems. However, the modified exhaust ventilation with local table-exhaust ventilation and heating-ventilation-air conditioning system performance were urgent issues for reducing levels of formaldehyde indoor air in the dissection room.

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.

Thiel embalming in neonates: methodology and benefits in medical training

Current teaching and training methods for surgical techniques in the pediatric population involve artificial models (manikins), animals or adult human cadavers embalmed using various techniques. We found no references in the literature concerning the use of the Thiel method in the pediatric population. The aim of this study, therefore, was to assess the viability of using pediatric human cadavers embalmed through Thiel’s technique and to compare them with standard pediatric manikins. After donation of a 24-week stillborn, the Thiel technique was carried out for fixation following the usual protocol. A video recording with eye-tracking glasses was used to perform an examination, and techniques. The same procedures were conducted on a pediatric manikin. Medical students, medical residents and physicians were asked to respond to questions in an online survey after being shown the video. A total of 92 responses were obtained. The Thiel-embalmed stillborn was assessed as superior to the manikin in all items. Our study confirmed that this technique is feasible even with extremely small donors. The value of this form of preservation for medical training is not widely known though it is receiving increasing interest. Our results show that Thiel fixation in pediatrics is clearly more highly valued than a manikin and offers great potential. This innovative application of the Thiel method in the pediatric population is technically possible. It poses no additional difficulties and is very positively assessed for undergraduate and postgraduate teaching.

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.

Contributions of the Thiel's Method in teaching and researching anatomy

INTRODUCTION

Knowledge of the human body is based on teaching and research. Anatomy remains an essential prerequisite for medical personnel to know the human body. The idea of Thiel's technique is to preserve the natural texture, volume, color and shape of the body. The objective of this study was to analyze a literature review of this technique from the perspective of anatomy teaching and biomechanical research.

METHOD

We have taken up the process of Thiel's method from the original publication, stating the known applications of this technique in teaching and research. We have integrated into our study the specific advantages of using bodies preserved by this method in intertropical countries with a warm climate: the example of Gabon.

DISCUSSION

Biomechanical research and teaching of medical and surgical sciences are regularly performed on human cadavers. Anatomical dissection therefore represents one of the main activities of anatomy laboratories. We have limited our analysis to aspects of anatomy teaching, research, and clinical and surgical practice.

CONCLUSION

We have sought to popularize the Thiel body preservation technique. It offers many advantages. Teaching and research on human cadavers preserved by this method is an educational alternative. The simulation centre creates the conditions of a surgical block for the learners. We recommend this technique to anatomists and clinicians. This technique seems to be very interesting for structures with a limited number of bodies.

Functional anatomy of the sagittal bands and mechanisms of extensor tendon dislocation: a cadaveric study

We investigated the functional anatomy of the radial sagittal band and possible mechanisms involved in its spontaneous and traumatic rupture using seven cadaveric hands. First, the extensor tendon excursion and the change in angle between the sagittal bands and the tendon path were measured during metacarpophalangeal joint flexion. The radial bands were then divided in two different ways that mimicked spontaneous or traumatic rupture. We found no significant correlation between the extensor tendon excursion and the change in angle of the sagittal bands in the middle and ring fingers. Dislocation could occur when the radial sagittal band was only partially divided. This may explain why conservative treatment of tendon dislocation in the middle and ring fingers is feasible. Complete section of the sagittal bands in the little finger caused ulnar dislocation of the extensor tendon in only one out of seven hands.

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.

What is the precaecocolic fascia?

The precaecocolic fascia, previously known as Jackson's membrane, is a variable vascular peritoneal fold between the ascending colon and the right posterolateral abdominal wall. First described in 1913, it was originally thought to be of developmental or inflammatory origin and associated with abdominal pain. This investigation aimed to review its frequency, form and structure and look for evidence of association with malformation of the bowel, or previous inflammation. 26 dissecting room cadavers were studied to identify the precaecocolic fascia, any malrotation of the colon or signs of previous inflammation: adhesions, surgical scars, or absence of the appendix. Its structure was examined histologically and latex injections were used to trace the arteries. Membranes comparable with previous descriptions of the precaecocolic fascia occurred in 12 of 26 abdomens. They varied in form and size from long and translucent to short, thick, and opaque. In structure, the fascia resembled a fold of peritoneum containing a thickened fibrous lamina. Large thin-walled arteries in the fascia crossed the arteries in the wall of the colon at the point of attachment. No significant association with colonic malrotation or markers of previous inflammation were found. Attention should be paid to the definition of the precaecocolic fascia and "membrane" seems a more appropriate term than "fascia". It is one of a recognized group of peritoneal folds/bands, doubtful in origin but unlikely to be post-inflammatory. It may modify colonic mobility or complicate colonic operations.

Phonosurgery Training in Human Larynx Preserved with Thiel's Embalming Method

BACKGROUND

To describe the suitability of larynges preserved with Thiel's embalming method for phonosurgery training.

METHODS

A training model for phonosurgery techniques simulating vocal pathology and glottal insufficiency is developed to compare and evaluate the perception of embalmed vocal cords through a voluntary and anonymous survey rated on a scale of 1-5. A total of 10 residents and young otolaryngologists participated in the surgical training in phonosurgery.

RESULTS

Ten larynges preserved in formalin and 10 Thiel's embalmed larynges were used for the investigation. Phonosurgery procedures were performed following microflap and injection laryngoplasty techniques. The larynges preserved with Thiel's method demonstrated vocal cords that maintain their pliability and good tissue quality allowing a sensation of realism compared to the living body and providing suitable conditions for realistic laryngeal training. Participants held a positive experience, believed them to be useful and that these models of embalmed larynges were similar to the clinical setting and improved skills and confidence in performing phonosurgery.

CONCLUSIONS

The human larynges embalmed with Thiel's method maintain the pliability of the vocal cords, thus representing a unique model to practice and reproduce training for endolaryngeal procedures without the risks of contamination, anatomical variation, or rigidity of other models.

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.

Characterization of the mechanical properties of human parietal bones preserved in modified larssen solution, formalin and as fresh frozen

PURPOSE

Although the fresh frozen (FF) cadaver is preferred for surgical applications, it is limited due to short usage time, unsuitable for reuse and the risk of infection. Due to its limited use, FF cadavers, which are covered by import in countries with insufficient body donation cause low-cost effectiveness. With the increase of real human tissue specimen necessities for surgical training, long-term preservation of the cadavers is crucial due to changes in mechanical properties. Therefore, studies on embalming solutions have increased in recent years.

METHODS

We quantify the biomechanical properties of human parietal bones preserved via modified larssen solution (MLS) and compare the results with the specimens preserved as FF and fixed with 10% formalin-based solution (F10). The rectangular samples of 24 parietal bones of male individuals were resected from MLS-embalmed, F10-embalmed and FF cadavers to form three groups each containing eight samples. These specimens were tested longitudinally to identify mechanical properties.

RESULTS

The tensile test results showed that there is not a significant difference between the groups in terms of stiffness, elastic modulus, strain at ultimate stress, failure strain and effective plastic strain. However, the yield stress, ultimate stress, yield strain, failure stress and total energy and post-yield properties are significantly lower in F10 than MLS and FF groups.

CONCLUSION

It is observed that the mechanical properties of MLS preserved and FF parietal bones have almost similar properties. Thus, it can be concluded that MLS is a suitable fixative solution for bone studies and bone-related surgical anatomy training applications.

Learning Gains of Liver Resection and Transplantation Workshop on Genelyn® Embalmed Human Cadavers: Surgical Gastroenterologists' Perceptions

BACKGROUND

In the light of increased requirement for liver transplantation procedures, it is pertinent to develop bankable human expertise in the areas of liver resection and anastomoses. The alternative simulator sources available for learning surgical skills might not always provide the realistic learning gains as provided by human cadavers, especially in terms of haptic and tactile fidelity. For the first time, we have used Genelyn® embalmed cadavers (GEC) for training the surgical gastroenterologists in liver resection and transplantation procedures and we wish to document our experience of using them to facilitate the learning of liver resection procedures.

MATERIALS AND METHODS

A cross-sectional satisfaction survey fitting to the first level of the Kirkpatrick model for training evaluation was performed among participating surgical gastroenterologists of liver resection and transplantation training workshop using GEC. Visual, haptic and tactile characteristics of the liver and related structures were assessed along with overall satisfaction of the workshop.

RESULTS

Eleven surgical gastroenterologists had participated in the workshop conducted using three GEC. Nine participants agreed that the transection of liver parenchyma was similar to reality. However, two opined that the liver parenchyma was a bit harder to resect. Identification of portal pedicle, dissection of the peri-portal area and securing vascular anastomoses also had an acceptable level of similarity to real life. The two parameters that received a unanimous degree of the agreement are mobilization of liver and cannulation of key vessels for perfusion.

CONCLUSION

Participants of the cadaveric surgical skills training workshop opined that the soft-embalmed cadaver using Genelyn® is an excellent realistic model for practicing liver resection and transplantation surgery.

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.

The Usefulness of Saturated Salt Solution Embalming Method for Oral Surgical Skills Training: A New Cadaveric Training Model for Bone Harvesting

The purpose of this study was to assess the usefulness of saturated salt solution-embalmed cadavers for oral surgical skills training related to bone graft harvesting. Two half-day surgical skills training workshops were held at the Tokyo Medical University utilizing eight cadavers embalmed with the saturated salt solution. A total of 22 participants including oral surgeons, residents, and dentists attended the workshop. Surgical training consisted of six procedures related to intraoral and extraoral bone harvesting. The participants were surveyed to assess self-confidence levels for each surgical procedure before and after completion of each workshop. The Wilcoxon signed-rank test was used to compare the differences between each median score before and after the workshop. There were statistically significant increases in the self-assessed confidence scores in bone harvesting procedures for the zygomatic bone (P = 0.003), maxillary tuberosity (P = 0.002), and other sites (P < 0.001). The anatomical features of saturated salt solution-embalmed cadavers were also examined. The textures of the oral mucosa and skin were similar to those of living individuals. The structure of bone tissues was well-preserved and the hardness was realistic. Consequently, all procedures were performed with sufficient realism. The saturated salt solution method has a relatively low cost of preparation and storage, and almost no odor. The authors suggest that saturated salt solution-embalmed cadavers could provide a new model for oral surgical skills training in bone harvesting.

Comparison of four posterior approaches of the ankle: A cadaveric study

OBJECTIVES

The purpose of this study is to provide a detailed comparison of 4 posterior approaches of the ankle: the posteromedial, modified posteromedial (mPM), Achilles tendon-splitting (TS), and posterolateral approaches.

METHODS

Cadaveric dissections were performed to assess the influence of the medial and lateral retraction forces on the neuro-vascular bundle with suspension scales and to measure the medial and lateral exposed areas of the posterior tibia and talus. Data was acquired with the ankle in neutral position and in plantar flexion.

RESULTS

Both the mPM and TS approaches provided excellent visualization of the posterior tibia with the ankle in plantar flexion (16.6 cm2 and 16.2 cm2, respectively). The medial aspect of the posterior tibia, however, was significantly better exposed in the mPM approach than in the TS approach with the ankle in neutral position (8.9 cm2 vs 6.5 cm2). The lower value for medial retraction force in the mPM approach (1.9 N in neutral position and 0.9 N in plantar flexion) indicated a lower risk of injury to the neuro-vascular bundle (the tibial nerve and the posterior tibial artery). The posterior talus, however, is best visualized through the TS approach with the ankle in neutral position (4.5 cm2).

CONCLUSIONS

The current study demonstrated the usefulness of the mPM approach. When internal fixation of the fibula is unnecessary, the mPM approach is preferable, considering the potential damage to the Achilles tendon associated with the TS approach.

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

INTRODUCTION

Surgical skills training has traditionally been limited to formalin embalming that does not provide a realistic model. The aim of this study was to qualitatively and quantitatively compare Thiel and phenol-based soft-embalming techniques: qualitatively in a surgical training setup, and quantitatively by comparing the mechanical and histomorphometric properties of skin specimens embalmed using each method.

MATERIALS AND METHODS

Thirty-four participants were involved in surgical workshops comparing Thiel and phenol-based embalmed bodies. Participants were asked to evaluate the utility of the different models for surgical skills training. In parallel, tensile elasticity evaluation was performed on skin flaps from six fresh-frozen cadavers. Flaps were divided into three groups for each specimen: fresh-frozen, Thiel, and phenol-based embalmed and compared together at 1 month or 1 year after embalming. A histological investigation of the skin structural properties was performed for each embalming type using haematoxylin and eosin and Masson's trichrome.

RESULTS

All participants rated the phenol-based specimens consistently better or equivalent to Thiel for the evaluated parameters. Quantitatively, there were statistically significant differences for the tensile elasticity between the embalming techniques (p < .05). There were no significant differences for the tensile elasticity between phenol-based embalmed skin and fresh state (p = .30), and no significant difference between embalming time was reported (p = .47). Histologically, the integrity of the skin was better preserved with the phenol-based technique.

CONCLUSION

Phenol-based embalming provides as realistic or better of a model as Thiel embalming for surgical training skills and was generally preferred over Thiel model. The phenol-based embalming better preserved the integrity of the skin.

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.

Thiel embalming: Quantifying histological changes in skeletal muscle and tendon and investigating the role of boric acid

Cadaver preservation methods impact their utilization in anatomical research and teaching. Thiel-embalmed cadavers show flexibility, however, the cause remains poorly understood. This study aimed to (1) describe qualitative and quantitative histological differences between Thiel-embalmed and formalin-fixed skeletal muscle and tendon tissue; (2) investigate whether boric acid in Thiel solution is solely responsible for modification of tissues; and (3) explore whether the modifications observed could potentially explain the mechanisms underpinning flexibility of Thiel cadavers. Skeletal muscle and tendon samples were harvested from mice preserved using formalin, Thiel solution, or modified-Thiel solution (without boric acid). Using standard H&E and Gomori's trichrome histological methods, tissues were examined to determine whether differences were apparent between the preservative treatments. Differences were present between the Thiel and formalin-fixed tissues; formalin-fixed samples remained substantially more intact while Thiel-embalmed samples showed fiber fragmentation and lack of nuclei. The mean cell diameter of Thiel-embalmed muscle (24.4 μm) was significantly smaller (P < 0.005) than formalin-fixed muscle (40.7 μm). There was significantly greater (P < 0.005) fragmentation in Thiel-embalmed muscle (631.5 per 1 mm² ) compared to formalin-fixed muscle (75.4 per 1 mm² ). Samples embalmed using modified-Thiel showed a severe lack of integrity within internal tissue structure. This suggests that Thiel solution significantly alters tissue structure at cellular level, with quantitative data demonstrating measurable differences between Thiel and formalin-fixed specimens. While the precise mechanism for these alterations remains unknown, it is shown that boric acid is not the only component of Thiel responsible for degradation of internal tissue structure. Clin. Anat., 33:696-704, 2020. © 2019 Wiley Periodicals, Inc.

Proximity of the Carotid Bifurcation to the Laryngeal Prominence: Results of a Cadaver Study and Recommendations for Safe Pulse Palpation

BACKGROUND/PURPOSE

The carotid bifurcation (CB) is the location of the carotid sinus and the baroreceptors and is also a major site for atherosclerotic plaque formation. Health care providers have therefore been cautioned to avoid the CB during carotid pulse palpation (CPP) to prevent triggering the baroreflex, occluding an artery, or propagating a thrombus. Potential risks of adverse events during CPP may be greater for older adults due to age-related vascular changes and increased risk of baroreceptor hypersensitivity. The exact location of the CB relative to easily identifiable landmarks has, however, not been well-studied. The purpose of this descriptive study was to identify the location of the CB relative to key landmarks in a cadaver sample and to make recommendations allowing clinicians to avoid the CB during CPP.

METHODS

The CB and other regional landmarks in 17 male and 20 female cadavers were exposed by dissection and pins were placed at all landmarks. Digital calipers were then used to measure the distance between the CB and all landmarks.

RESULTS AND DISCUSSION

The mean vertical distance from the laryngeal prominence (LP) to the CB was 25.14 mm for females and 36.13 mm for males. No CBs were located below the LP. Ninety-four percent of female CBs and 100% of male CBs were located above the LP, and 74% of female subjects and 87% of male subjects had CBs greater than 20.00 mm superior to the LP. No clinically relevant relationships were found between the CB and any of the other measured landmarks.

CONCLUSIONS

Based on this cadaver sample, CPP below the level of the LP in a supine individual would be unlikely to compress the CB and thus unlikely to trigger the baroreflex or occlude the region of greatest atherosclerotic buildup. If a pulse is not palpable below the LP, moving vertically up to 1 cm above the LP in a supine individual would be likely to compress the CB in only a small number of cases.

A Reusable Perfused Human Cadaver Model for Surgical Training: An Initial Proof of Concept Study

OBJECTIVES

Today's surgical trainees have less exposure to open vascular and trauma procedures. Lightly embalmed cadavers may allow a reusable model that maximizes resources and allows for repeat surgical training over time.

METHODS

This was a three-phased study that was conducted over several months. Segments of soft-embalmed cadaver vessels were harvested and perfused with tap water. To test durability, vessels were clamped, then an incision was made and repaired with 5-0 polypropylene. Tolerance to suturing and clamping was graded. In a second phase, both an arterial-synthetic graft and an arterial-venous anastomosis were performed and tested at 90 mmHg perfusion. In the final phase, lower extremity regional perfusion was performed and vascular control of a simulated injury was achieved.

RESULTS

Seven arteries and six veins from four cadavers were explanted. All vessels accommodated suture repair over 6 weeks. There was minor leaking at all previous clamp sites. In the anastomotic phase, vessels tolerated grafting, clamping, and perfusion without tearing or leaking. Regional perfusion provided a life-like training scenario.

CONCLUSIONS

Explanted vessels of soft-embalmed cadavers show adequate durability over time with realistic vascular surgery handling characteristics. This shows promise as initial proof of concept for a reusable perfused cadaver model. Further study with serial regional and whole-body perfusion is warranted.

The antimicrobial capacity of embalming solutions: a comparative study

AIMS

Infectious health risks are associated with handling human cadavers and to decrease such risks, cadavers are embalmed using different chemicals. The aim of this study is to quantify the amount of micro-organisms present in different regions of human cadavers before embalming, after embalming and over a period of 8 months.

METHODS AND RESULTS

Human cadavers were embalmed using Thiel, formalin, Genelyn and the Imperial College London soft-preservation (ICL-SP) solution with two cadavers per technique. Sterile swabs were used to collect samples from different regions. Samples were collected every 2 months. All cadavers had a high number of microbial colonies before embalming. While no colonies were detected on formalin and Genelyn embalmed cadavers post-embalming, the number of colonies decreased significantly in Thiel-embalmed cadavers and stayed relatively the same in ICL-SP-embalmed cadavers.

CONCLUSIONS

Formalin-embalmed cadavers showed the strongest disinfecting abilities followed by Thiel-embalmed cadavers, then Genelyn-embalmed cadavers and finally by ICL-SP cadavers.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study highlights how under researched this area is and the evident variation in the antimicrobial abilities of different embalming solutions on the cadaver as a whole and within different regions of the same cadaver.

Simulation Training Methods in Neurological Surgery

Simulation training plays a paramount role in medicine, especially when it comes to mastering surgical skills. By simulating, students gain not only confidence, but expertise, learning to apply theory in a safe environment. As the technological arsenal improved, virtual reality and physical simulators have developed and are now an important part of the Neurosurgery training curriculum. Based on deliberate practice in a controlled space, simulation allows psychomotor skills augment without putting neither patients nor students at risk. When compared to the master-apprentice ongoing model of teaching, simutation becomes even more appealing as it is time-efficient, shortening the learning curve and ultimately leading to error reduction, which is reflected by diminished health care costs in the long run. In this chapter we will discuss the current state of neurosurgery simulation, highlight the potential benefits of this approach, assessing specific training methods and making considerations towards the future of neurosurgical simulation.

A comparison of embalming fluids on the structures and properties of tissue in human cadavers

Cadaveric material has long been used to teach anatomy and more recently to train students in clinical skills. The aim of this study was to develop a systematic approach to compare the impact of four embalming solutions on the tissues of human cadavers. To this end, a formalin-based solution, Thiel, Genelyn and Imperial College London soft-preservation (ICL-SP) solution were compared. The effect of these chemicals on the properties of the tissue was assessed by measuring the range of motion (ROM) of joints and measuring the dimensions of different structures on computed tomography (CT) images before and after embalming. The mean changes in the ratio (angle to ROM) differed statistically between embalming methods (Welch Statistic _3,1.672  = 67.213, p = 0.026). Thiel embalmed cadavers showed an increase in range of motion while ICL-SP cadavers remained relatively the same. Genelyn and formalin embalmed cadavers registered a notable decrease in range of motion. Furthermore, investigation into the impact of the embalming chemicals on the dimensions of internal organs and vessels revealed that Thiel embalming technique leads to a decrease in the dimension of the cardiovascular system alone while formalin-based solutions maintain the shape of the organs and vessels investigated. Our findings suggest that the joints of cadavers' embalmed using ICL-SP technique may faithfully mimic that of unembalmed cadavers and that formalin is necessary to retain shape and size of the organs and vessels investigated in this study. Despite this, a study with larger numbers of cadavers is required to confirm these findings.

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.

Saturated Salt Solution Cadaver-Embalming Method Improves Orthopaedic Surgical Skills Training

BACKGROUND

Human cadaver surgical skills training offers the highest-fidelity simulation of the operative environment, with the potential to enhance surgeon training and to reduce operative risks to patients. Embalming extends the duration that a cadaveric specimen may be used for surgical skills training and reduces the risk of disease transmission, but it can alter the properties of the cadaver tissue, reducing the simulation fidelity and training quality. The purpose of this controlled laboratory study was to evaluate 3 embalming methods, formaldehyde solution, alcohol-glycol solution, and saturated salt solution, and to compare their relative performance in a 2-week orthopaedic surgical skills training course.

METHODS

The 3 embalming methods were applied to 3 cadavers each. Joint range of motion and joint stiffness were measured prior to dissection. The cadavers were assessed by 4 orthopaedic surgeons on the first and last days of the training course in 4 domains: tissue visual fidelity, tissue tactile fidelity, odor, and overall suitability for surgical skills training using 7-point Likert scales. Sterile specimens for bacterial and fungal culture were obtained from cadaver muscle tissue on the fourth and fifteenth days of use.

RESULTS

All cadaver groups were successfully preserved without putrefaction and were utilized over the duration of the training course. The saturated salt solution cadavers had supple joints with excellent motion and were rated highly across all domains. The saturated salt solution cadaver joint motion, stiffness, visual and tactile tissue fidelity, odor, and suitability for surgical skills training were significantly superior (p < 0.05) to the formaldehyde solution and alcohol-glycol solution cadavers.

CONCLUSIONS

The saturated salt embalming method is inexpensive and logistically straightforward and preserves human cadavers at room temperature in a state suitable for high-fidelity orthopaedic surgical skills training.

Clinical Cadavers as a Simulation Resource for Procedural Learning

"See one, do one, teach one" remains an unofficial, unsanctioned framework for procedural skill learning in medicine. Appropriately, medical educators have sought alternative simulation venues for students to safely learn their craft. With the end goal of ensuring competence, educational programming will require the use of valid simulation with appropriate fidelity. While cadavers have been used for teaching anatomy for hundreds of years, more recently they are being repurposed as a "high-fidelity" procedural skill learning simulation resource. Newly deceased, previously frozen, and soft-preserved cadavers, such as those used in Baltimore and Halifax, produce clinical cadavers with high physical and functional fidelity that can serve as simulators for performing many high-acuity procedures for which there is otherwise limited clinical or simulation opportunities to practice. While access and cost may limit the use of cadavers for simulation, there are opportunities for sharing resources to provide an innovative procedural learning experience using the oldest of medical simulation assets, the human body.

Learning anatomy through Thiel- vs. formalin-embalmed cadavers: Student perceptions of embalming methods and effect on functional anatomy knowledge

Thiel-embalmed cadavers, which have been adopted for use in anatomy teaching in relatively few universities, show greater flexibility and color retention compared to formalin-embalmed cadavers, properties which might be considered advantageous for anatomy teaching. This study aimed to investigate student attitudes toward the dissection experience with Thiel- compared to formalin/ethanol-embalmed cadavers. It also aimed to determine if one embalming method is more advantageous in terms of learning functional anatomy through the comparison of student anterior forearm functional anatomy knowledge. Student opinions and functional anatomy knowledge were obtained through use of a questionnaire from students at two medical schools, one using Thiel-, and one using more traditional formalin/ethanol-embalmed cadavers. Both the Thiel group and the formalin group of students were surveyed shortly after completing an anterior forearm dissection session. Significant differences (P-values <0.01) in some attitudes were found toward the dissection experience between cohorts using Thiel- vs. formalin-embalmed cadavers. The Thiel group of students felt more confident about recognizing anatomy in the living individual, found it easier to identify and dissect anatomical structures, and indicated more active exploration of functional anatomy due to the retained flexibility of the cadaver. However, on testing, no significant difference in functional anatomy knowledge was found between the two cohorts. Overall, although Thiel embalming may provide an advantageous learning experience in some investigated areas, more research needs to be carried out, especially to establish whether student perception is based on reality, at least in terms of structure identification. Anat Sci Educ 11: 166-174. © 2017 American Association of Anatomists.

LENGTH CHANGE OF THE SHORT EXTERNAL ROTATORS OF THE HIP IN COMMON STRETCH POSITIONS: A CADAVERIC STUDY

Background

Stretching of the deep rotators of the hip is commonly employed in patients with lumbosacral, sacroiliac, posterior hip, and buttock pain. There is limited research demonstrating the effectiveness of common stretching techniques on the short external rotators of the hip.

Purpose

The objective of this study was to evaluate length change during stretching of the superior and inferior fibers of the piriformis, superior gemellus, obturator internus, and inferior gemellus.

Study Design

Repeated-measures laboratory controlled cadaveric study.

Methods

Seventeen hip joints from nine embalmed cadavers (5 male; 4 female) with an age between 49-96 years were skeletonized. Polypropylene strings were attached from the origin to insertion sites of the short external rotators. The change of length (mm) noted by excursion of the strings was used as a proxy for change in muscle length, when the hip was moved from the anatomical position to four specific stretch positions: 1) 45 ° internal rotation from hip neutral flexion/extension, 2) 45 ° external rotation from 90 ° hip and knee flexion, 3) 30 ° adduction from 90 ° of hip and knee flexion, and 4) 30 ° of adduction with the hip and knee flexed so the lateral malleolus contacted the lateral femoral epicondyle of the contralateral limb , were recorded.

Results

There was a significant effect on string displacement by stretch position, F (15,166) = 14.67, p < .0005; Wilk's L = .097, partial n2 = .540. The greatest displacement of the strings corresponding to the superior piriformis, inferior piriformis, and the superior gemellus occurred in 30 ° adduction from 90 ° of hip and knee flexion. The obturator internus and inferior gemellus had the largest string displacement with 45 ° internal rotation from neutral flexion/extension.

Conclusions

While all stretch positions caused a significant string displacement indicating length changes of the deep rotators of the hip, the three stretch positions that caused the greatest change were: 1) 30 ° adduction from 90 ° of hip and knee flexion, 2) 45 ° internal rotation from neutral flexion/extension, and 3) 45 ° external rotation with 90 ° hip and knee flexion.

Clinical Relevance

This study has clinical implications for the effectiveness of specific stretching techniques on the short external rotators of the hip with the potential to improve the validity of stretching protocols for patients with posterior hip or buttock pain. The piriformis and superior gemellus had a larger change in length when adducting the hip from 90 ° degrees of hip and knee flexion. The obturator internus and inferior gemellus had a greater length change when internally rotating the hip from neutral flexion/extension.

Level of Evidence

3.

Anatomical analysis of human ligamentum flavum in the cervical spine: Special consideration to the attachments, coverage, and lateral extent

BACKGROUND

Posterior decompression surgeries of cervical spine such as laminoplasty and laminoforaminotomy are well established and increasing in aging population. The anatomical knowledge of cervical ligamentum flavum (LF) is critical to perform posterior spinal surgeries, however, few studies have evaluated it, especially the relation of LF and neural foramen.

METHODS

The whole spine was removed en bloc from 15 formalin-embalmed human cadavers and then divided into two segments along the pedicle bases. A total of 90 LFs from C2-C3 to C7-T1 were measured manually from the ventral side before being painted with iron powder containing contrast agent and scanned by computed tomography. We recorded dimensions, coverage of adjacent laminae, and the relationships between LF and neural foramen or facet joints. Three-dimensional CT data was used to evaluate manually limited areas and make reconstructed images.

RESULTS

LF height gradually increased from C2-C3 to C7-T1, and gradually decreased from medial to lateral within each level. LF width and thickness were relatively constant from cranial to caudal. The laminar surface covered by LF gradually increased from 33% in para midline and 30% laterally at C2, and increased to 70% in para midline and 47% laterally at C6, this trend was not completed at C7. The empty zone of the laminar surface (without LF coverage) was located at the upper half of each lamina; this zone gradually decreased from cranial to caudal. The craniomedial side of the cervical facet joint was covered by a mean 4.6 ± 0.7 mm of LF, however, LF did not enter the cervical neural foramen.

CONCLUSIONS

LF did not enter the neural foramen in cervical spine unlike lumbar spine. This information might be critical to avoid neurological deterioration after cervical laminoplasty or laminoforaminotomy. Surgeons would imagine the attachments and coverage of LF and its relation to posterior bony structures to perform safe posterior cervical surgeries.

Virtual Reality simulator for dental anesthesia training in the inferior alveolar nerve block

Objectives

This study shows the development and validation of a dental anesthesia-training simulator, specifically for the inferior alveolar nerve block (IANB). The system developed provides the tactile sensation of inserting a real needle in a human patient, using Virtual Reality (VR) techniques and a haptic device that can provide a perceived force feedback in the needle insertion task during the anesthesia procedure.

Material and Methods

To simulate a realistic anesthesia procedure, a Carpule syringe was coupled to a haptic device. The Volere method was used to elicit requirements from users in the Dentistry area; Repeated Measures Two-Way ANOVA (Analysis of Variance), Tukey post-hoc test and averages for the results’ analysis. A questionnaire-based subjective evaluation method was applied to collect information about the simulator, and 26 people participated in the experiments (12 beginners, 12 at intermediate level, and 2 experts). The questionnaire included profile, preferences (number of viewpoints, texture of the objects, and haptic device handler), as well as visual (appearance, scale, and position of objects) and haptic aspects (motion space, tactile sensation, and motion reproduction).

Results

The visual aspect was considered appropriate and the haptic feedback must be improved, which the users can do by calibrating the virtual tissues’ resistance. The evaluation of visual aspects was influenced by the participants’ experience, according to ANOVA test (F=15.6, p=0.0002, with p<0.01). The user preferences were the simulator with two viewpoints, objects with texture based on images and the device with a syringe coupled to it.

Conclusion

The simulation was considered thoroughly satisfactory for the anesthesia training, considering the needle insertion task, which includes the correct insertion point and depth, as well as the perception of tissues resistances during the insertion.

Position of the sciatic nerve and effect of gluteus maximus release during hip arthroplasty

Eight Thiel embalmed hips were dissected. The distance between the sciatic nerve and the femoral neck was measured before and after hip dislocation, and before and after release of the gluteus maximus tendon. There was a significant reduction in the mean distance between the neck of femur and the sciatic nerve in both the gluteus maximus tendon release and the unreleased groups at 60° and 90° of hip flexion, p < 0.05. The mean distance between the neck of femur and sciatic nerve was greater in the release group for all positions.

The utility of cadaver-based approaches for the teaching of human anatomy: A survey of British and Irish anatomy teachers

Utilizing reality anatomy such as dissection and demonstrating using cadavers has been described as a superior way to create meaning. The chemicals used to embalm cadavers differentially alter the tissue of the human body, which has led to the usage of different processes along the hard to soft-fixed spectrum of preserved cadavers. A questionnaire based approach was used to gain a better insight into the opinion of anatomists on the use of preserved cadavers for the teaching of human anatomy. This study focused on anatomy teachers in the United Kingdom and Ireland. From the 125 participating anatomists, 34.4% were medically qualified, 30.4% had a PhD in a non-anatomical science and 22.4% had a PhD in an anatomical science, these figures include ten anatomists who had combinations of MD with the two other PhD qualifications. The main findings from the questionnaire were that 61.6% of participants agreed that hard-fixed formalin cadavers accurately resemble features of a human body whereas 21.6% disagreed. Moreover, anatomists rated the teaching aids on how accurately they resemble features of the human body as follows: plastic models the least accurate followed by plastinated specimens, hard fixed cadavers; soft preserved cadavers were considered to be the most accurate when it comes to resembling features of the human body. Though anatomists considered soft preserved cadavers as the most accurate tool, further research is required in order to investigate which techniques or methods provide better teaching tool for a range of anatomical teaching levels and for surgical training. Anat Sci Educ 10: 137-143. © 2016 American Association of Anatomists.

Ischiofemoral impingement: defining the lesser trochanter-ischial space

PURPOSE

The purpose of this study was to define changes in the ischial-lesser trochanteric space associated with medial and lateral hip rotation in neutral and 10° of extension and adduction.

METHODS

Twenty-five hip joints from 14 embalmed cadavers (7 males and 7 females) were used for this study. The pelvic region of each cadaver was skeletonized, and the hip capsule released distally. With the hip joint in 0° flexion-extension/abduction-adduction, the distance between the lesser trochanter and ischium was measured in: neutral rotation, 40° medial rotation, and 60° lateral rotation. A one-way ANOVA with post hoc analysis determined the difference in the ischiofemoral space in these three positions. An additional position was then tested by laterally rotating the femur with the hip joint positioned in 10° extension and adduction.

RESULTS

The average distance between the lesser trochanter and ischium was different (p < .0005) in neutral rotation, 40° medial rotation, and 60° lateral rotation at 2.8 cm (SD 1.1), 4.3 cm (SD 1.2), and 1.4 cm (SD 0.7), respectively. With the hip joint laterally rotated from a starting position of 10° extension and adduction, 21 of 25 (84 %) hips made contact between the lesser trochanter and ischium at an average position of 29° (SD 20) of lateral rotation.

CONCLUSIONS

The lesser trochanter is closest to the ischium in lateral rotation and is furthest away in medial rotation when the hip is in neutral flexion-extension/abduction-adduction. The lesser trochanter approximates the ischium when the hip is laterally rotated in 10° extension and adduction. The information gained through this investigation helps to define the pathomechanics associated with ischiofemoral impingement and validate clinical tests to diagnose ischiofemoral impingement.

Intubation biomechanics: laryngoscope force and cervical spine motion during intubation in cadavers—effect of severe distractive-flexion injury on C3–4 motion

OBJECTIVE

With application of the forces of intubation, injured (unstable) cervical segments may move more than they normally do, which can result in spinal cord injury. The authors tested whether, during endotracheal intubation, intervertebral motion of an injured C3–4 cervical segment 1) is greater than that in the intact (stable) state and 2) differs when a high- or low-force laryngoscope is used.

METHODS

Fourteen cadavers underwent 3 intubations using force-sensing laryngoscopes while simultaneous cervical spine motion was recorded with lateral fluoroscopy. The first intubation was performed with an intact cervical spine and a conventional high-force line-of-sight Macintosh laryngoscope. After creation of a severe C3–4 distractive-flexion injury, 2 additional intubations were performed, one with the Macintosh laryngoscope and the other with a low-force indirect video laryngoscope (Airtraq), used in random order.

RESULTS

During Macintosh intubations, between the intact and the injured conditions, C3–4 extension (0.3° ± 3.0° vs 0.4° ± 2.7°, respectively; p = 0.9515) and anterior-posterior subluxation (−0.1 ± 0.4 mm vs −0.3 ± 0.6 mm, respectively; p = 0.2754) did not differ. During Macintosh and Airtraq intubations with an injured C3–4 segment, despite a large difference in applied force between the 2 laryngoscopes, segmental extension (0.4° ± 2.7° vs 0.3° ± 3.3°, respectively; p = 0.8077) and anterior-posterior subluxation (0.3 ± 0.6 mm vs 0.0 ± 0.7 mm, respectively; p = 0.3203) did not differ.

CONCLUSIONS

The authors' hypotheses regarding the relationship between laryngoscope force and the motion of an injured cervical segment were not confirmed. Motion-force relationships (biomechanics) of injured cervical intervertebral segments during endotracheal intubation in cadavers are not predicted by the in vitro biomechanical behavior of isolated cervical segments. With the limitations inherent to cadaveric studies, the results of this study suggest that not all forms of cervical spine injury are at risk for pathological motion and cervical cord injury during conventional high-force line-of-sight intubation.

Acoustic characterization of Thiel liver for magnetic resonance-guided focused ultrasound treatment

BACKGROUND

The purpose of this work was to measure the essential acoustic parameters, i.e., acoustic impedance, reflection coefficient, attenuation coefficient, of Thiel embalmed human and animal liver. The Thiel embalmed tissue can be a promising, pre-clinical model to study liver treatment with Magnetic Resonance-guided Focused Ultrasound (MRgFUS).

MATERIAL AND METHODS

Using a single-element transducer and the contact pulse-echo method, the acoustic parameters, i.e., acoustic impedance, reflection coefficient and attenuation coefficient of Thiel embalmed human and animal liver were measured.

RESULTS

The Thiel embalmed livers had higher impedance, similar reflection and lower attenuation compared to the fresh tissue.

CONCLUSIONS

Embalming liver with Thiel fluid affects its acoustic properties. During MRgFUS sonication of a Thiel organ, more focused ultrasound (FUS) will be backscattered by the organ, and higher acoustic powers are required to reach coagulation levels (temperatures >56 °C).

Defining the greater trochanter-ischial space: a potential source of extra-articular impingement in the posterior hip region

The purpose of this study was to describe greater trochanteric-ischial impingement and the relative position of the hip joint where impingement occurs. Twenty-three hips from 13 embalmed cadavers (seven males and six females) with a lifespan ranging between 46 and 91 years were used for this study. The pelvic region of each cadaver was skeletonized leaving only the hip capsule and the sciatic nerve. From 90° of flexion, the hip was extended while maintaining a position of 30° abduction and 60° external rotation. The position of hip flexion was recorded when there was contact between the greater trochanter and the ischium. The procedure was repeated in 0° abduction. A Flexion-Abduction-External Rotation (FABER) test was then performed on all specimens with a positive finding defined as contact between the greater trochanter and the ischium. In 30° abduction, contact of the ischium and the greater trochanter occurred in 87% (20/23) of the hips at an average of 47° of flexion (SD 10; range 20–60°). In 0° abduction, a positive finding was noted in 39% (9/23) of hips at an average of 59° flexion (SD 6; range 52–70°). A positive finding in the FABER test position was noted in 96% (22/23) of hips. The greater trochanter can impinge on the ischium when the hip is extended from 90° flexion in a 60° externally rotated position. This impingement occurred more commonly when the hip was in 30° abduction compared with neutral abduction. The FABER test position consistently created greater trochanteric–ischial impingement.