Low viscosity silicone with less shrinkage for brain slices.

Plastination consists of replacing lipid and water with a curable polymer. This technique has numerous advantages, of which the production of non-toxic, inert, highly durable, dry, and easy maintenance and storage specimens stand out. Like all anatomical techniques, plastination also has disadvantages, and one of them is tissue shrinkage. The feasibility of using low viscosity domestic silicone (0,1Pa.s at 20°C) to plastinate brain slices was examined. Twenty humans, 10 millimeters (mm) brain slices were impregnated, ten slices each with two polymers [10 with domestic low viscosity polymer - P1 and 10 slices with Biodur® (0,45-0,6Pa.s at 20°C) S10]. Shrinkage was accessed by volume and area measurements. Volume shrinkage was significantly less in the slices impregnated with low viscosity domestic polymer, demonstrating the feasibility to plastinate brain slices with domestic low viscosity silicone polymer.

Through the fingers: Use of plastinated anatomical specimens for visually impaired students.

The plastination technique produces non-toxic human tissues, ensuring their safe handling in educational settings. This investigation aimed to understand if visually impaired students profit from the use of plastinated anatomical specimens in learning the anatomy of the nervous system. For this purpose, their learning performance was compared to sighted and blindfolded students recruited from three primary schools in Fortaleza city, in the state of Ceará. Initially, a questionnaire was applied before carrying out the pedagogical practice, followed by an anatomy lecture with practical components with the use of plastinated anatomical specimens and synthetic anatomical models of the nervous system. After these steps, the students answered the questionnaire previously applied. Our results showed that the tactile perception of the visually impaired participants was significantly more developed compared to sighted (p < 0.001) and the blindfolded (p < 0.0001) students. The average of correct answers in the reapplied questionnaire was higher in the groups that used plastinated specimens (p < 0.05). In conclusion, the use of plastinated specimens has proven to be an effective tool in promoting a better understanding of anatomical structures, mainly for students with or without visual impairments, making it a valuable asset in anatomy teaching.

First Experience of Plastination at 4150 Meters Above Sea Level, at the Altitude of La Paz, Bolivia / Primera Experiencia de Plastinación a 4150 Metros sobre el Nivel del Mar, en la Altura de La Paz, Bolivia

SUMMARY: Despite attempts to develop the plastination technique in Bolivia, standardized results have not yet been achieved that could be communicated via scientific publications. There is a great deal of misunderstanding around the technique, confusing it with classic techniques of inclusion in different types of resin, such as polyester and epoxy, but these protocols are not plastination. The aim of this work was to communicate the first standardized room-temperature plastination protocol with silicone in Bolivia, with the unique feature of doing so at the altitude of the city of La Paz, thus constituting the first communication of a plastination technique at 4,150 m.a.s.l. sub sede La Paz, La Paz, Bolivia.

En Bolivia, a pesar de los intentos en el desarrollo de la técnica de Plastinación, aún no se han alcanzado resultados estandarizados que pudieran ser comunicados por medio de publicaciones científicas. Existe una gran confusión al momento de desarrollar la técnica, confundiéndola con técnicas clásicas de inclusión en distintos tipos de reina, como poliéster y epoxy, pero no correspondiendo estos protocolos desarrollados a la técnica de plastinación. En este sentido, el objetivo de esta trabajo consistió en comunicar el primer protocolo estandarizado de plastinación a temperatura ambiente con silicona de Bolivia, con la particularidad de desarrollarlo en la altura de la ciudad de La Paz, constituyéndose, de esta manera, en la primera comunicación de una técnica de plastinación a 4.150 metros sobre el nivel del mar.

Conservation of Organs (Heart, Brain and Kidney) of Canine by Cold-Temperature Silicone Plastination in an Animal Anatomy Laboratory in Ecuador / Conservación de Órganos (Corazón, Encéfalo y Riñón) de Canino Mediante la Técnica de Plastinación en Silicona al Frío Realizada en Laboratorio de Anatomía Animal en Ecuador

SUMMARY: For the purposes of teaching anatomy, the use of cadaver preparations is considered the most efficient way of ensuring that students retain knowledge. Nevertheless, in Ecuador the use of animal specimens in universities must comply with the internationally accepted principles of replacement, reduction and refinement (3Rs). Plastination is an alternative technique which allows organs to be conserved in the long term and complies with the 3Rs. The object of the present work was to use cold-temperature silicone plastination with Biodur® products to obtain long-lasting, easy-to-handle canine organs for use as tools for the teaching of animal anatomy. Six canine cadavers were obtained from local animal protection charities. The hearts, brains and kidneys of the cadavers were dissected and fixed with formaldehyde 10 %. They were then dehydrated with acetone at -20 °C. The specimens were impregnated with Biodur® S10:S3 (-20 °C) and finally cured with Biodur® S6. We plastinated six hearts, twelve kidneys, four brains and one encephalic slice of canine. The application of cold-temperature plastination to canine organs followed the parameters established for the conventional protocol, enabling us to obtain organs of brilliant appearance, free of odours, in which the anatomical form was preserved. Thus the technique helped us to comply with the 3Rs, as we obtained easy-to-handle teaching models to replace fresh or formaldehyde-fixed samples for the teaching-learning of the canine anatomy.

En la enseñanza de la Anatomía, el uso de preparaciones cadavéricas se considera el método que permite a los estudiantes retener el conocimiento de una forma más eficiente. No obstante, en Ecuador, el uso de especímenes animales en las universidades se debe realizar bajo el principio internacional de reemplazo, reducción y refinamiento (3Rs). La técnica de plastinación es una técnica alternativa que permite preservar órganos a largo plazo y que se adapta al principio de las 3Rs. El objetivo del trabajo fue utilizar la técnica de plastinación en silicona al frío con productos Biodur® para obtener órganos caninos duraderos y manejables útiles como herramienta para la enseñanza de la anatomía animal. Se obtuvieron seis cadáveres de caninos de fundaciones locales para la protección animal. Se realizaron disecciones de corazones, cerebros y riñones de los cadáveres caninos. Los órganos se fijaron con formalina al 10 %. A continuación, se llevó a cabo la deshidratación con acetona a -20 °C. Los especímenes fueron impregnados con S10:S3 Biodur® (-20 °C) y al final fueron curados con Biodur® S6. Se lograron plastinar seis corazones, doce riñones, cinco encéfalos y un tallo encefálico de canino. La técnica de plastinación al frío utilizada para obtener órganos de canino conservó los parámetros empleados en el protocolo convencional y permitió obtener órganos que presentaron aspecto brillante, ausencia de olores y mantuvieron la forma anatómica. Por lo que, la técnica facilitó cumplir con el principio de las 3Rs al obtenerse modelos didácticos fáciles de manipular que pueden reemplazar muestras frescas o formolizadas en el proceso de enseñanza-aprendizaje de la anatomía del canino.

Is domestic polyester suitable for plastination of thin brain slices?

Plastination is a technique used to preserve biological tissues while retaining most of their original appearance. In the technique, developed by Dr. Gunther von Hagens in 1977, specimens were impregnated with a polymer, such as silicone, epoxy, or polyester. Considered the most suitable material for brain plastination, polyester has a wide application in teaching and research compared with imaging techniques. The materials for plastination are usually imported from Germany and more expensive than domestic products. If domestic polymers were to enter the market it would favor the expansion of plastination in Brazil. Hence, this study evaluated the feasibility of using domestic polyesters to replace the usual Biodur® (P40) in plastination of brain slices. For this evaluation, 2-mm-thick sections of bovine brains were prepared and plastinated with domestic polyester. Slices were compared before impregnation and after curing using standardized photographs taken after dehydration and after curing. Plastination followed the standard protocol: fixation, dehydration, forced impregnation, and curing. Fifteen brain slices were plastinated with each polyester (P40, P18, and C1-3). There was no significant difference in the percent shrinkage between groups after plastination of P18 and P40, but the curing time of Cristalan© polymer was too short for impregnation. Therefore, no initiator was used for C polymers impregnation. Thus, domestic polyester P18 was a viable option for the process.

Three-Dimensional Anatomy of the Hypoglossal Canal: A Plastinated Histologic Study.

OBJECTIVE: To provide a precise description of the morphology and morphometry of the hypoglossal canal (HC) and its relationship with surrounding structures by using the epoxy sheet plastination technique. METHODS: Thirty human cadaveric heads were plastinated into 5 sets of gross transparent plastination slices and 43 sets of ultrathin plastination sections. The HC were examined at both macro- and micro levels in these plastination sections and the reconstructed 3-dimensional visualization model. RESULTS: The HC was an upward arched bony canal with a dumbbell-shaped lumen. According to the arched trajectory of its bottom wall, the HC could be divided into a medial ascending segment and a lateral descending segment. The thickness of the compact bone in the middle part of the HC was thinner than that at the intracranial and extracranial orifices. In 14 of 43 sides (32.6%), the posterior wall or the roof of the HC were disturbed by passing venous channels which communicated the posterior condylar emissary vein and the inferior petroclival vein. The trajectory of hypoglossal nerve in HC is mainly from anterosuperior to posteroinferior. The meningeal dura and the arachnoid extended into the HC along the hypoglossal nerve to form the dural and arachnoid sleeves and then fused with the nerve near the extracranial orifice of the HC. CONCLUSIONS: Knowledge of the detailed anatomy of the HC can be helpful in avoiding surgical complications when performing surgery for lesions and the occipital condylar screw placement in this complex area.

Internal Structural Connections in the Popliteus Tendon Complex with Posterior Cruciate Ligament and Clinical Implications / Conexiones Estructurales Internas en el Complejo Tendón Poplíteo con Ligamento Cruzado Posterior e Implicaciones Clínicas

SUMMARY: At present, the anatomical relationship the mid-portion of popliteus tendon complex (PTC) and the surrounding tissues is still unclear, especially its relationship to the posterior cruciate ligament (PCL). It affected the anatomical reconstruction of the posterolateral complex (PLC) injury. A total of 30 cases of the adult human knee joint fixed with formalin were used. Sagittal sections were made in 14 knee joints by the P45 plastination technique and dissection of 16 cases of knee joints. The P45 section revealed that the popliteus muscle fascia ran superiorly over the posterior edge of the tibial intercondylar eminence, and turned forward to be integrated into the PCL. Laterally, near the posterior edge of the lateral tibial plateau, the popliteus tendon penetrates through the articular capsule (AC), where two dense fibrous bundles were given off upwards by the popliteus tendon: one was the ventral fiber bundle, which ran superiorly over the posterior edge of the tibial plateau and then moved forwards to connect with the lateral meniscus; the dorsal fibers bundle ascended directly and participated in the AC. Meanwhile, the popliteus muscle dissection showed that at the posterior edge of the platform of the lateral condyle of the tibia, at the tendon-muscle transition, the PTC and AC were anchored to PCL.

En la actualidad, la relación anatómica entre la porción media del complejo tendinoso poplíteo (CTP) y los tejidos circundantes aún no está clara, especialmente su relación con el ligamento cruzado posterior (LCP). Esto afecta la reconstrucción anatómica de la lesión del complejo posterolateral (LCP). Se utilizaron un total de 30 casos de articulaciones de rodillas humanas de individuos adultos fijadas con formalina. Se realizaron cortes sagitales en 14 articulaciones de rodilla mediante la técnica de plastinación P45 y disección de 16 casos de articulaciones de rodilla. La sección P45 reveló que la fascia del músculo poplíteo discurría superiormente sobre el margen posterior de la eminencia intercondílea tibial y giraba hacia delante para integrarse en el LCP. Lateralmente, cerca del margen posterior de la platillo tibial lateral, el tendón poplíteo penetra a través de la cápsula articular (CA), donde el tendón poplíteo desprendió hacia arriba dos haces fibrosos densos: uno era el haz de fibras ventral, que corría superiormente sobre el margen posterior de la meseta tibial y luego se movió hacia adelante para conectar con el menisco lateral; el haz de fibras dorsales ascendía directamente y participaba en la CA. Por su parte, la disección del músculo poplíteo mostró que en el margen posterior del platillo del cóndilo lateral de la tibia, en la transición tendón-músculo, el CTP y el AC estaban anclados al LCP.

A Clinical and Anatomical Study on the Localization of the Temporal Branch of the Facial Nerve Crossing the Zygomatic Arch / Estudio Clínico y Anatómico sobre la Localización del Ramo Temporal del Nervio Facial que Cruza el Arco Cigomático

SUMMARY: To clarify the path of the temporal branch of facial nerve (TB) crossing the zygomatic arch (ZA). Eighteen fresh adult heads specimens were carefully dissected in the zygomatic region, with the location of TB as well as its number documented. The hierarchical relationship between the temporal branch and the soft tissue in this region was observed on 64 P45 plastinated slices. 1. TB crosses the ZA as type I (21.8 %), type II (50.0 %,), and type III (28.1 %) twigs. 2. At the level of the superior edge of the ZA, the average distance between the anterior trunk of TB and the anterior part of the auricle is 36.36±6.56 mm, for the posterior trunk is 25.59±5.29 mm. At the level of the inferior edge of the ZA, the average distance between the anterior trunk of TB and the anterior part of the auricle is 25.77±6.19 mm, for the posterior trunk is 19.16±4.71 mm. 3. The average length of ZA is 62.06±5.36 mm. TB crosses the inferior edge of the ZA at an average of 14.67±6.45 mm. TB crosses the superior edge of the ZA at an average of 9.08±4.54 mm. 4. At the level of the ZA, TB passes on the surface of the pericranium while below the SMAS. The TB obliquely crosses the middle 1/3 part of the superior margin of the ZA and the junction of the middle 1/3 part and the posterior 1/3 part of the inferior margin of the ZA below the SMAS while beyond the periosteum. It is suggested that this area should be avoided in clinical operation to avoid the injury of TB.

El objetivo de estudio fue esclarecer el trayecto del ramo temporal del nervio facial (RT) que cruza el arco cigomático (AC). Se disecaron la región cigomática de 18 especímenes de cabezas sin fijar de individuos adultas y se documentó la ubicación del RT y su número de ramos. La relación jerárquica entre el ramo temporal y el tejido blando en esta región se observó en 64 cortes plastinados o P45. 1º El RT cruza el AC como tipo I (21,8 %), tipo II (50,0 %) y tipo III (28,1 %). 2º A nivel del margen superior del AC, la distancia promedio entre el tronco anterior de RT y la parte anterior de la aurícula fue de 36,36±6,56 mm, para el tronco posterior fue de 25,59±5,29 mm. A nivel del margen inferior del AC, la distancia promedio entre el tronco anterior del RT y la parte anterior de la aurícula era de 25,77±6,19 mm, para el tronco posterior era de 19,16±4,71 mm. 3º La longitud media de RT fue de 62,06±5,36 mm. EL RT cruzaba el margen inferior del AC a una distancia media de 14,67±6,45 mm. El RT cruzaba el margen superior del AC a una distancia media de 9,08±4,54 mm. 4º Anivel del AC, el RT pasaba por la superficie del pericráneo mientras se encuentra por debajo del SMAS. El RT cruza oblicuamente el tercio medio del margen superior del AC y la unión del tercio medio y el tercio posterior del margen inferior del AC por debajo del SMAS, más allá del periostio. Se sugiere que esta área debe evitarse en la operación clínica para evitar la lesión de la RT.

An improved plastination method for strengthening bamboo culms, without compromising biodegradability.

Biomaterials are increasingly being designed and adapted to a wide range of structural applications, owing to their superior mechanical property-to-weight ratios, low cost, biodegradability, and CO2 capture. Bamboo, specifically, has an interesting anatomy with long tube-like vessels present in its microstructure, which can be exploited to improve its mechanical properties for structural applications. By filling these vessels with a resin, e.g. an applied external loading would be better distributed in the structure. One recent method of impregnating the bamboo is plastination, which was originally developed for preserving human remains. However, the original plastination process was found to be slow for bamboo impregnation application, while being also rather complicated/methodical for industrial adaptation. Accordingly, in this study, an improved plastination method was developed that is 40% faster and simpler than the original method. It also resulted in a 400% increase in open-vessel impregnation, as revealed by Micro-X-ray Computed Tomography imaging. The improved method involves three steps: acetone dehydration at room temperature, forced polymer impregnation with a single pressure drop to - 23 inHg, and polymer curing at 130 °C for 20 min. Bamboo plastinated using the new method was 60% stronger flexurally, while maintaining the same modulus of elasticity, as compared to the virgin bamboo. Most critically, it also maintained its biodegradability from cellulolytic enzymes after plastination, as measured by a respirometric technique. Fourier transform infrared-attenuated total reflection, and thermogravimetric analyses were conducted and showed that the plastinated bamboo's functional groups were not altered significantly during the process, possibly explaining the biodegradability. Finally, using cone calorimetry, plastinated bamboo showed a faster ignition time, due to the addition of silicone, but a lower carbon monoxide yield. These results are deemed as a promising step forward for further improvement and application of this highly abundant natural fiber in engineering structures.

Variaciones anatómicas de las arterias radial y ulnar en miembros superiores plastinados / Anatomical variations of radial and ulnar arteries in plastinated upper limbs

Los avances en el área de la salud, con el desarrollo de nuevos procedimientos diagnósticos y quirúrgicos, requieren un conocimiento cada vez más preciso de la anatomía humana. La difusión de la disposición variable de la anatomía resulta primordial no sólo en el campo de la especialización o el postgrado, sino por sobre todo, en el pregrado, desde donde se formarán los especialistas que luego desarrollarán esas nuevas prácticas clínicas y quirúrgicas que requerirán una sólida formación anatómica. Es por esto que la aplicación correcta de técnicas anatómicas en las muestras anatómicas es fundamental para que esta enseñanza en el pregrado pueda desarrollarse de manera eficiente, teniendo la plastinación un rol fundamental en este sentido. El objetivo de este trabajo consistió en dar a conocer el hallazgo de variaciones anatómicas arteriales en los miembros superiores de una muestra humana sometida al proceso de plastinación para fomentar, por un lado, la importancia del conocimiento anatómico en el pregrado, el postgrado y las especialidades, como así también la relevancia de la preservación a largo plazo de material biológico para la difusión continua de la anatomía.

SUMMARY: Advances in the area of health with the development of new diagnostic and surgical procedures require an increasingly precise knowledge of human anatomy. The diffusion of the variable arrangement of anatomy is essential not only in the field of specialization or postgraduate, but above all, in the undergraduate, from where the specialists will be trained who will later develop these new clinical and surgical practices that will require a solid anatomical background. This is why the correct application of anatomical techniques in anatomical samples is essential for this undergraduate teaching to be developed efficiently, plastination having a fundamental role in this regard. The aim of this work was to report the discovery of anatomical variations in the upper limbs of a human sample subjected to the plastination process to promote, on one hand, the importance of anatomical knowledge in undergraduate, postgraduate and specialties, as well as the relevance of long- term preservation of biological material for the continued dissemination of anatomy.

Detailed anatomy of the corpora-glans ligament via the P45 plastination method / Anatomía detallada de los ligamentos cuerpo cavernoso-glande mediante el método de plastinación P45

SUMMARY: The corporo-glans ligament is the ligament connecting the corpus cavernosum and the glans of the penis. The anatomical description of the corporo-glans ligaments shape is still uncertain, this knowledge affects penile reconstructive procedures. The anatomy of the corporo-glans ligament was analyzed and recorded via observing sagittal sections of 10 different penile P45 plastination sections. According to the P45 plastination sections, the corporo-glans junction displayed a fibrous tissue band connecting the distal ends of the two corpus cavernous (CC) with the glans penis (GP). The fibrous band was a round-obtuse shape and ran deep into the glans of the penis and occupied about 2/3 of the whole GP. The original end was laid in a socket embedded in the GP. The density of the fibers of the ligament at the original end close to the tunica albuginea was less than that of the other parts. The fibers originating from the tunica albuginea, directly extended to the blind end of the two CC, covering the distal end of the two CC.

El ligamento cuerpo cavernoso-glande es el ligamento que conecta el cuerpo cavernoso y el glande del pene. La descripción anatómica de la forma de los ligamentos cuerpo cavernoso -glande aún es incierta; este conocimiento afecta los procedimientos reconstructivos del pene. La anatomía del ligamento cuerpo cavernoso-glande se analizó y registró mediante la observación de 10 secciones sagitales diferentes del pene a través de plastinación P45. Según las secciones de plastinación, la unión cuerpo-glande mostraba una banda de tejido fibroso que conectaba los extremos distales de los dos cuerpos cavernosos con el glande del pene. La banda fibrosa tenía una forma redonda y obtusa y se adentraba profundamente en el glande del pene ocupando alrededor de 2/3 de él. En su origen se coloca en un espacio profundo en el glande del pene. La densidad de las fibras del ligamento cuerpo cavernoso-glande en su origen cercano a la túnica albugínea era menor que el de las otras partes. Las fibras que se originan en la túnica albugínea, se extienden directamente hasta el extremo ciego de los dos cuerpos cavernosos, cubriendo el extremo distal de estos.

Influence of Plastination on Ultrasound Transmission Through the Human Skull.

Development, optimization and validation of transcranial ultrasound methods require the use of fresh human or animal skulls. However, to avoid fresh skull degradation over time, fixation methods are required for conservation, such as formaldehyde buffer solution. This method allows for conservation of the skull properties over a relatively long period, but requires specific conditioning (de-gassing) and storage conditions, such that its practical use is limited. Plastination appears to be a unique solution for the preservation and transportation of body parts without constraints. However, the influence of this conservation process has yet to be characterized with respect to ultrasound transmission to verify that the acoustic and mechanical properties of the skulls are not altered by the plastination process. The objective of the study described here was to quantify the effect of plastination on ultrasound transmission through the temporal and parietal areas of the human skull between 200 kHz and 2 MHz. To achieve this, transmission measurements were performed on three different skulls and four areas before and after plastination. It was found that the plastination process results in a transmission loss of 5 dB. Moreover, results indicate that the plastination process does not induce any phase shift in the transmitted signal, validating the proper use of plastinated skulls for in vitro measurements and development of new transcranial ultrasound methods.

Development of an interactive multidisciplinary platform for the bovine neuroanatomy study / Desarrollo de una plataforma interactiva multidisciplinar para el estudio de la neuroanatomía bovina

SUMMARY: The anatomy study is part of the basic cycle of disciplines that composes Veterinary Medicine college curriculum, and its comprehension is essential for other courses subject understanding. However, the current student's profile, the reduced time frame of superior education programs, and the multidisciplinary approach nowadays have made anatomy teaching method outdated and ineffective. Addressing the problem we developed an interactive and multidisciplinary platform based on the blended learning methodology, which could serve as a valuable tool for bovine neuroanatomy comprehension. To produce a new study tool, photos from bovine specimens fixed in formaldehyde, platinated brain pieces sectioned in a metameric order, as well as histological slides of the bovine central nervous system were used. These materials were applied to photos and schemes production, that were correlated with image exams correlation, as well as written content and videotaped classes. The obtained content was compiled into a digital platform, that can serve as an effective additional method to bovine central nervous system study. Furthermore, our results serve as a guide for the development of other blended learning methodologies in veterinary medicine and anatomy teaching. The platform provides a great tool for those who wish to accomplish a better understanding of bovine neuroanatomy and its clinical, surgical and image diagnosis correlations.

El estudio de la anatomía forma parte del ciclo básico de disciplinas que componen el currículo de la facultad de Medicina Veterinaria, y su comprensión es fundamental para el entendimiento de las materias de otros cursos. Sin embargo, el perfil del estudiante actual, la reducción de los tiempos de los programas de educación superior y el enfoque multidisciplinario actual han hecho que el método de enseñanza de la anatomía sea obsoleto e ineficaz. Abordando el problema desarrollamos una plataforma interactiva y multidisciplinar basada en la metodología blended learning, que podría servir como una valiosa herramienta para la comprensión de la neuroanatomía bovina. Para producir una nueva herramienta de estudio, se utilizaron fotografías de especímenes bovinos fijados en formaldehído, piezas de cerebro plastinadas y seccionadas en un orden metamérico, así como láminas histológicas del sistema nervioso central bovino. Estos materiales se utilizaron en la producción de fotos y esquemas, que se correlacionaron con exámenes de imágenes, así como contenido escrito y clases grabadas en video. El contenido obtenido se compiló en una plataforma digital, que puede servir como un método adicional y eficaz para el estudio del sistema nervioso central bovino. Además, nuestros resultados sirven como guía para el desarrollo de otras metodologías de aprendizaje semipresencial en la enseñanza de la medicina veterinaria y la anatomía. La plataforma proporciona una gran herramienta para aquellos que deseen lograr una mejor comprensión de la neuroanatomía bovina y sus correlaciones clínicas, quirúrgicas y de diagnóstico por imágenes.

Bony structures at the attachment areas of the cruciate ligaments in human knee joints and their clinical significance-studied using the P45 plastination technique / Estructuras óseas en las áreas de inserción de los ligamentos cruzados en las articulaciones de la rodilla humana y su importancia clínica, estudiadas mediante la técnica de plastinación P45

SUMMARY: For treating cruciate ligament injuries, especially for characterizing the mechanics of the tunnel in cruciate ligament reconstruction, correctly understanding the bony information of the attachment area of the cruciate ligaments is significant. We studied 31 knee joints of middle-aged Chinese adults using the P45 sheet plastination technique, focusing on the attachment areas of the cruciate ligaments, especially the bony structures. The trabeculae at the attachment area were distributed radially and extended deep into the medial wall of the lateral condyle of the femur. However, in the anterior part of the intercondylar eminence, the trabeculae of the anterior group were parallelly arranged along the tendinous fibers of the anterior cruciate ligament, while the trabeculae of the posterior group were parallelly arranged along the perpendicular direction of the anterior cruciate ligament fibers. Similarly, at the attachment area of the lateral wall of the medial condyle of the posterior cruciate ligament, the trabeculae extended radially toward the deep medial condyle. Deep in the posterior part of the intercondylar eminence, the trabeculae were arranged longitudinally. In the anterior part of the intercondylar eminence, the trabeculae were parallelly arranged along the perpendicular directions of ligament fibers. The distribution patterns of the trabecular at the attachment areas of the cruciate ligaments at the ends of the femur and tibia were different. This difference should be considered when orthopedic surgeons reconstruct anterior cruciate ligaments.

Para el tratamiento de lesiones de los ligamentos cruzados, especialmente para caracterizar la mecánica del túnel en su reconstrucción, es importante comprender correctamente la información ósea del área de inserción de estos ligamentos. Estudiamos 31 articulaciones de rodilla de individuos chinos, adultos, de mediana edad, utilizando la técnica de plastinación de láminas P45, centrándonos en las áreas de unión de los ligamentos cruzados, especialmente en las estructuras óseas. Las trabéculas en el área de inserción se distribuyeron radialmente y se extendieron profundamente en la pared medial del cóndilo lateral del fémur. Sin embargo, en la parte anterior de la eminencia intercondílea, las trabéculas del grupo anterior estaban dispuestas paralelamente a lo largo de las fibras tendinosas del ligamento cruzado anterior, mientras que las trabéculas del grupo posterior estaban dispuestas paralelamente a lo largo de la dirección perpendicular de las fibras del ligamento cruzado anterior. De manera similar, en el área de inserción en la cara lateral del cóndilo medial del ligamento cruzado posterior, las trabéculas se extendían radialmente y profundas hacia el cóndilo medial. Profundamente en la parte posterior de la eminencia intercondílea, las trabéculas estaban dispuestas longitudinalmente. En la parte anterior de la eminencia intercondílea, las trabéculas estaban dispuestas paralelamente a lo largo de las direcciones perpendiculares de las fibras del ligamento. Los patrones de distribución del tejido óseo trabecular en las áreas de unión de los ligamentos cruzados en los extremos del fémur y la tibia eran diferentes. Estas diferencias deben tenerse en consideración cuando los cirujanos ortopédicos reconstruyen los ligamentos cruzados anteriores.

Applying a unified model of fiber dissection, tractography, microscopic anatomy and plastination techniques for basic neuroanatomy education: Hacettepe University experience / Aplicación de un modelo unificado de disección de fibras, tractografía, anatomía microscópica y técnicas de plastinación para la educación básica en neuroanatomía: experiencia de la Universidad Hacettepe

SUMMARY: Anatomy education has gathered together a great many of many new modalities and was modified from classical lecture-based and laboratory practice system to the blended modules. In the scope of the present study, we develop a new, practical, cost- effective and efficient three dimensional (3D) educational model, which aimed to be helpful for the detection and better understanding of basic neuroanatomy education. Tractographic imaging, fiber dissection, microscopic anatomy and plastination techniques were applied to the white matter regions of the two brains. After the photographs that were taken were converted to 3D images, the specimens were plastinated. By way of establishing an educational model as a whole, we applied it to 202 second-year medical students. The students were separated into two groups when they attended to the theoretical lecture. Group 1 took the classical laboratory education; on the other hand, Group 2 received the newly designed educational model. Pre and post-tests were introduced to each group before and after laboratory sessions, respectively. The success scores were put to comparison. The average achievement scores of each group showed increase significantly (p<0.05) after the laboratory sessions, besides the increase in the post-test results of Group 2 was more statistically significant (p<0.05). Consequently, this new educational model enriched by newly designed unified methods could be regarded as useful for grasping and improving the basic neuroanatomy knowledge.

La educación en anatomía ha reunido una gran cantidad de nuevas modalidades, modificándose el sistema clásico de la práctica del laboratorio y de las clases basadas en conferencias, hacia los módulos combinados. En el ámbito del presente estudio, desarrollamos un modelo educativo tridimensional (3D) nuevo, práctico, rentable y eficiente, que pretendía ser útil para la detección y una mejor comprensión de la educación básica en neuroanatomía. Se tomaron imágenes tractográficas, disección de fibras, anatomía microscópica y técnicas de plastinación en los cerebros. Después de convertir las fotografías que se tomaron en imágenes 3D, se plastinaron los especímenes. A modo de establecer un modelo educativo en su conjunto, lo aplicamos a 202 estudiantes de segundo año de medicina. Los estudiantes fueron separados en dos grupos cuando asistieron a la clase teórica. El Grupo 1 tomó la educación clásica de laboratorio; por su parte, el Grupo 2 recibió el nuevo modelo educativo diseñado para el estudio. Se introdujeron pruebas previas y posteriores a cada grupo, antes y después de las sesiones de laboratorio. Se compararon las puntuaciones. Los puntajes promedio de rendimiento de cada grupo mostraron un aumento significativo (p<0,05) después de las sesiones de laboratorio. Además, se obtuvo un aumento en los resultados positivos, posteriores a la prueba del Grupo 2, siendo estadísticamente significativo (p<0,05). En consecuencia, este modelo educativo, enriquecido por métodos unificados de nuevo diseño, podría considerarse útil para captar y mejorar los conocimientos básicos de neuroanatomía.

Formation and Fixation of the Annulus of Zinn and Relation With Extraocular Muscles: A Plastinated Histologic Study and Its Clinical Significance.

Purpose: This study aimed to clarify the formation and fixation of the annulus of Zinn (AZ) and its relationship with the extraocular muscles by using ultrathin plastination and three-dimensional models. Methods: Eighteen cadaveric heads (36 sides of the orbital apex) were plastinated to coronal (16 sides), sagittal (13 sides), and horizontal (5 sides) ultrathin plastination sections to be investigated at both macroscopic and microscopic levels. One cadaveric head was used for endoscopic dissection to identify anatomic landmarks. Results: There were two fibrous triangles adhered to both ends of the anterior surface of the optic strut. The superior rectus muscle originated from the superior fibrous triangle, and the lateral, inferior, and medial rectus muscles emerged from the inferior fibrous triangle. It was not until 5.46 ± 0.41 mm anterior to the optic strut that the complete tendinous ring composed of rectus muscles, optic nerve sheath, and periosteum was formed. The superior oblique and levator palpebrae superioris muscles originated from the medial fibrous band of the AZ. At the posterior of the AZ, there was a potential passage between the medial rectus muscle and the optic nerve. Conclusions: The fixation of the AZ was composed of the connection of the annular tendon to the optic strut posteriorly and the attachment of the complete tendinous ring to the lesser and greater wings of the sphenoid bone anteriorly. The triangular route area between the optic nerve and medial rectus muscle was located on the anterior side of the base of the optic strut.

The medial wall and medial compartment of the cavernous sinus: an anatomic study using plastinated histological sections.

The medial wall of the cavernous sinus (CS) has a significant role in evaluation and treatment of pituitary adenomas. This study was conducted to clarify the fine architecture of the medial wall and medial compartment of the CS at both macro- and micro-levels in twenty-one human cadaveric heads by using the epoxy sheet plastination technique. The sellar part medial wall is an intact dural layer that separates the CS from the pituitary gland. This dural wall adhered to the diaphragma sellae and the periosteum of the sella turcica to form fibrous triangles. Eight micro-protrusions of the pituitary gland were found at both sides of that wall. The thickness of the sellar part medial wall at its central portion was significantly thinner than that at the other surrounding portions. From the superior view, tortuous intracavernous carotid arteries can be divided into outward bending type and inward bending type. The inward bending intracavernous carotid was apt to bent towards the central part of the sellar part medial wall, where there were usually wide and short fibrous bands with more densely stained connective tissues between them. The micro-protrusion of the pituitary gland in the medial wall of the CS could provide an anatomical basis for the occult tumor invasion and the recurrence of residual tumor. Different bending facing states of tortuous intracavernous carotid arteries in the lateral direction may be a factor of the determination of the direction of growth of pituitary tumors.

Plastination with low viscosity silicone: strategy for less tissue shrinkage.

Plastination is an anatomical technique for preserving biological tissues based on the principle of replacing body fluids with a curable polymer. An inconvenient aspect of this technique is the tissue shrinkage it causes; several studies seek ways to reduce or avoid this shrinkage. Additionally, there are no studies in the literature that quantitatively evaluate the use of low viscosity silicones in plastination having shrinkage of tissue as a parameter. Therefore, this study aimed to evaluate the use of Silicones S10 (Biodur) and P1 (Polisil) in the plastination of different types of biological tissues of a sliced human body, having as a parameter the tissue shrinkage caused in the forced impregnation stage. Human cardiac, pulmonary, splenic, renal, hepatic, muscular, and bone tissues were analyzed. For such purpose, a male human body was used, sliced in 13-15-mm-thick pieces, having as a parameter the before and the after plastination with the different silicones. The standard protocol of the plastination of the slices was followed: dehydration, forced impregnation, and curation. Half of the pieces obtained were plastinated with silicone P1 (group P1) and the other half with S10 (group S10). All tissues and anatomical segments analyzed in this study showed less or equal shrinkage when plastination of the control group (S10) was compared with that of the P1 group. Therefore, we concluded that the lower viscosity silicone promoted less tissue shrinkage, making it a viable alternative to the reference.

A new concept of the fiber composition of cervical spinal dura mater: an investigation utilizing the P45 sheet plastination technique.

PURPOSE: Few reports have been published regarding the microanatomy of the dura mater located at the craniovertebral junction (CVJ). In clinic, the precise microanatomy of the CVJ dura mater would be taken into account, for reducing surgical complications and ineffective surgical outcomes. The main objective of the present investigation was to further elucidate the fiber composition and sources of the cervical spinal dura mater. METHODS: The formalin-fixed adult head and neck specimens (n = 21) were obtained and P45 plastinated section method was utilized for the present study. The fibers of the upper cervical spinal dura mater (SDM) were examined in the P45 sagittal sections in the CVJ area. All photographic documentation was performed via a Canon EOS 7D Mark camera. RESULTS: The posterior wall of the SDM sac at CVJ was found to be composed of stratified fibers, which are derived from three sources: the cerebral dura mater, the occipital periosteum, and the myodural bridge (MDB). The proper layer of the cerebral dura mater passes over the brim of the foramen magnum and enters the vertebral canal to form the inner layer of the SDM, and the fibers originating from the periosteum of the brim of the foramen magnum form the middle layer. The fibers of the MDB are inserted into the SDM and form its outer layer. It was found that the total number of fibers from each origin varied in humans. CONCLUSION: At the CVJ, the posterior wall of the SDM is a multi-layered structure composed of three different originated fibers. The cerebral dura mater, the periosteum located at the brim of the foramen magnum, and MDB contribute to the formation of the SDM. The present study would be beneficial to the choice of surgical approach at the CVJ and the protection of the SDB.

Colorimetric evaluation of cross-sectional silicone plastination of the Total head region of sheep and Deplastination of the histological sections of brain tissue.

The aim of the study is to protect and preserve the cross-sectional diagnostic characteristics of the anatomy samples by using silicone plastination method, to examine them both macroscopically and microscopically, and to use them as an educational material. After the dissection procedures of 10 total sheep heads obtained from the slaughterhouse were completed, they were freshly frozen and sliced to prepare cross-sectional samples. Then, statistical analysis was performed after the colorimetric measurements. For microscopic examination, 30 brain samples were divided into three groups (Fresh-F, plastination-P, plastination/deplastination-P/D). Of the total brain samples, 20 were subject to routine plastination protocol. After the plastination/deplastination procedure, the changes occurring in cerebral histology were compared. In terms of tissue preservation, the effect of plastination and deplastination was examined using a light microscope. Plastinates subject to silicone plastination under room temperature were very similar to their natural appearance, and it was observed that they preserved their morphological features. Colour changes in the tissues were statistically evaluated. Volumetric shrinkages were observed as qualitative, especially in the brain. As a result of the evaluation done, it was seen that deplastination with toluene is not possible for the brain tissues. In addition, it was not possible to take cross sections of the plastinated tissues that were not deplastinated. On the contrary, findings regarding that deplastination with 5% sodium methoxide dissolved in methanol can allow microscopic examination in long-term preserved plastinated brain tissues were obtained.