Association between clinical and surgical variables with postoperative outcomes in patients treated for intestinal obstruction for non-malignant conditions: a cross-sectional study.

Intestinal obstruction is considered a frequent surgical pathology related to previous surgical procedures. Many different factors can lead to different outcomes when surgical management is needed. Therefore, we aim to describe the factors related to morbidity and mortality in surgical management of IO in a single-center experience. Retrospective observational study with a prospective database, in which we described patients who underwent surgical management due to intestinal obstruction between 2004 and 2015. Demographics, perioperative data, surgical outcomes, morbidity, and mortality were described. 366 patients were included. Female were 54.6%. Mean age was 61.26. Laparoscopic approach was done in 21.8% and the conversion rate was 17.2%. Intestinal resection was performed in 37.9% of the cases. Postoperative complications were observed in 18.85%. Reintervention and mortality were 9.5% and 4.1% respectively. Laparoscopic approach shows lesser time of intestinal transit (mean 28.67 vs. mean 41.95 h), and restart of oral intake after surgery (mean 96.06 vs. mean 119.65) compared with open approach. Increased heart rate and intensive care unit length of stay were related with mortality (p 0.01 and 0.000 respectively). For morbidity, laparotomy and need and duration of ICU stay were related with any complication statistically significant (p 0.02, 0.008, 0.000 respectively). Patients with increased heart rate in the emergency room, decreased amount of intravenous fluids, need and higher length of stay in the intensive care unit, and delay in resuming oral intake after surgery appear to have poor outcomes. Laparoscopic approach seems to be a safe and feasible approach for intestinal obstruction in selected patients.

Macroscopic brain gray matter staining: historical protocol overview and neuroanatomy learning applications in second-year medical students.

Macroscopic staining in anatomical samples of the central nervous system is a technique that has been used for decades to achieve better differentiation of multiple gray matter structures, such as the cortex, basal ganglia, and cerebellar nuclei. Staining methods are based on using the different components of the brain, mainly the lipids present in the white matter. These techniques have been progressively forgotten while computer renderings are increasing; however, as a primary exposure to surgical anatomy, stained brain specimens are considered a helpful tool. We aim to summarize different staining techniques, their principles, and their current applications for neuroanatomy learning purposes. In total, four gray matter staining protocol descriptions (Mulligan's, Roberts's, Alston's, and Prussian Blue) were performed, as well as Likert scale surveys of second-year medical students about their perceptions of the stained sections. The results showed that the different macroscopic stains for brain tissue are based on lipid and reactant interactions, intending to increase the white matter (WM) and gray matter (GM) contrast. The search also showed that most staining protocols would take 2 days to develop. Efficient preservation options include submerging the sections in formaldehyde solutions, formaldehyde-free solutions, ethanol, or applying plastination techniques. Based on the student's perspective, the stained slices seem to be a valuable alternative to facilitate the study and identification of the basal ganglia and their relationships with the white matter (from 51.2 to 72% based on the Likert scale) compared with the non-stained sections. In conclusion, macroscopic staining of brain tissue continues to be a valuable tool for comprehensively studying the brain. Further research is needed to determine the efficacy of stained specimens as teaching tools.

Face, Content, and Construct Validity Evaluation of Simulation Models in General Surgery Laparoscopic Training and Education: A Systematic Review.

BACKGROUND: Laparoscopic technical surgical skills (LTS) are considered a fundamental competence for General Surgery residents. Several simulation tools (ST) have been explored to develop LTS. Although a plethora of systematic reviews evaluate the translation of LTS developed in simulation to real surgery, there is a lack of evidence that clarifies effectiveness of different validated ST in acquisition of LTS in surgical residents. The aim of this systematic review (SR) is to summarize published evidence on ST validation used for surgery education and training. METHODS: A protocol was published in PROSPERO. A SR was carried out following PRISMA guidelines. Complete published articles in English or Spanish that validate either content or construct, plus another form of validation of ST to acquire LTS in general surgery were included. Articles that used only one validation or did not validate an ST were excluded. RESULTS: 1052 publications were initially identified across all searched databases. Title review identified 204 studies eligible for full text screening. 10 studies were included for final review. Two studies assessed both face and content, 4 face and construct, and 4 face, content and construct validity. None of the studies presented comparable outcomes due to metrics variation and scores used for the validation strategies. CONCLUSIONS: This study assessed validated laparoscopic simulation models, particularly in content and construct validity. Articles reported an increased use of simulation models in laparoscopic training with positive feedback from trainees, but few studies reported validation of training model. Validation strategies are not standardized, limiting comparability between them.

Viability and characterization trial of a novel method as an alternative to formaldehyde and Walter-Thiel cadaveric preservation for medical education and surgical simulation.

INTRODUCTION: Despite its toxic and carcinogenic nature, formaldehyde is a widely used reactant for specimen preservation. With the need of specimens for both anatomical and surgical training, alternative preservation solutions (PS) have been proposed, however, their use is limited due to high costs and complexity. Hence, a new formaldehyde-free solution (FFS) is evaluated as a potential alternative for anatomical and surgical training. METHODS: Qualitative and Quantitative data were acquired. Specimens preserved using three different methods were selected. Flexibility was measured by joints goniometry and pneumoperitoneum pressures were evaluated followed by an exploratory laparoscopy. Undergraduate student's perceptions on cadavers preserved with different PS were obtained using surveys and focus groups. RESULTS: The main reason why cadaveric specimens were considered as useful tools was the perceived interaction with real tissues and the 'practical' concept of getting in touch with what students would be facing in the future as physicians, what we call "hands on" activities. FFS treated specimens showed better joint-movement ranges in comparison to other methods and pneumoperitoneum was acquired after 5mmHg CO2 pressure. Students appreciated working with corpses regardless the technique used, however FFS specimens were defined as less uncomfortable, while presenting no sensory discomfort. CONCLUSIONS: Even though alternative PS are effective, high costs and complexity restrict their usage. Cadavers preserved with FFS had similar range of movements compared with Thiel. Students preferred to work with FFS rather than FF due to flexibility, color, and no sensorial hassles. Thus, we propose FFS as viable alternative to traditional PS.

Postoperative outcomes of minimally invasive adrenalectomy: do body mass index and tumor size matter? A single-center experience.

BACKGROUND: Since Gagner performed the first laparoscopic adrenalectomy in 1992, laparoscopy has become the gold-standard procedure in the treatment of adrenal surgical diseases. A review of the literature indicates that the rate of intra- and postoperative complications are not negligible. This study aims to describe the single-center experience of adrenalectomies; and explore the associations between body mass index (BMI) and tumor volume in main postoperative outcomes. METHODS: Retrospective observational study with a prospective database in which we described patients who underwent adrenalectomy between January 2015 and December 2020. Operative time, intraoperative blood loss, conversion rate, complications, length of hospital stay, and comparison of the number of antihypertensive drugs used before and after surgery were analyzed. Analysis of BMI and tumor volume with postoperative outcomes such as anti-hypertensive change (AHC) in drug usage and pre-operative conditions were performed. RESULTS: Forty-five adrenalectomies were performed, and all of them were carried out laparoscopically. Four were performed as a robot-assisted laparoscopy approach. Nineteen were women and 26 were men. Mean age was 54.9 ± 13.8 years. Mean tumor volume was 95.698 mm3 (3.75-1010.87). Mean operative time was shorter in right tumors (2.64 ± 0.75 h) than in left tumors (3.33 ± 2.73 h). Pearson correlation was performed to assess the relationship between BMI and AHC showing a direct relationship between increased BMI and higher change in anti-hypertensive drug usage at postoperative period r(45) = 0.92, p > 0.05 CI 95%. Higher tumor volume showed a longer operative time, r(45) = 0.6 (p = 0.000 CI 95%). CONCLUSIONS: Obese patients could have an increased impact with surgery with an increased change in postoperative anti-hypertensive management. Tumor volume is associated with increased operative time and blood loss, our data suggest that it could be associated with increased rates of morbidity. However, further prospective studies with larger sample sizes are needed to validate our results.

Histological analysis of an alkaline based tissue clearing technique for fetal musculoskeletal tissue / Análisis histológico de una técnica de limpieza de tejido de base alcalina para tejido musculoesquelético fetal

SUMMARY: Tissue clearing techniques are frequently used in the observation and description of anatomical structures and pathways without altering the three-dimensional layout of the anatomical specimen. Tissue optical clearing promotes preservation of three-dimensional structures, which allows the study of the internal anatomy in its original position and original spatial interaction. Among these techniques, Potassium Hydroxide (KOH) maceration clearing is one of the most widely used. However, the histological changes of tissue after KOH maceration have yet to be fully understood. Our aim is to describe the microscopical differences between macerated and normal tissue. To better understand said changes, two human fetuses with a gestation period of 16 to 28 weeks were cleared and processed for histological analysis. Microtome slides of the fetuses' lower limbs were obtained and stained with Hematoxylin & Eosin, Periodic Acid Schiff (PAS), and Masson's trichrome with the purpose of observing the histological and macromolecule composition changes in cleared tissue. Remarkable differences at a histological level regarding the composition of the cellular structures, since diaphanized tissues showed a predominance of extracellular matrix composed of collagen fibers with the absence of most of the nucleated cellular tissue. Phospholipid's saponification, nucleic acids degradation and a change on proteins structural properties are the main factors inducing clearing. At the same time, molecular stability of collagen in alkaline conditions allows the specimen to maintain its shape after the process.

RESUMEN: Las técnicas de limpieza de tejido se utilizan con frecuencia en la observación y descripción de estructuras y vías anatómicas sin alterar el diseño tridimensional de la muestra anatómica. El aclaramiento óptico de tejidos promueve la preservación de estructuras tridimensionales, lo que permite el estudio de la anatomía interna en su posición original y la interacción espacial original. Entre estas técnicas, el aclarado por maceración con Hidróxido de Potasio (KOH) es una de las más utilizadas. Sin embargo, los cambios histológicos del tejido después de la maceración con KOH aún no se han entendido por completo. Nuestro objetivo es describir las diferencias microscópicas entre el tejido macerado y el normal. Para entender mejor dichos cambios, dos fetos humanos con un período de gestación de 16 a 28 semanas fueron aclarados y procesados para análisis histológicos. Se obtuvieron microtomos de las extremidades inferiores de los fetos y se tiñeron con hematoxilina y eosina, ácido peryódico de Schiff (PAS) y tricrómico de Masson con el fin de observar los cambios histológicos y de composición de macromoléculas en el tejido aclarado. Diferencias notables a nivel histológico en cuanto a la composición de las estructuras celulares, ya que los tejidos diafanizados mostraban un predominio de matriz extracelular compuesta por fibras de colágeno con ausencia de la mayor parte del tejido celular nucleado. La saponificación de los fosfolípidos, la degradación de los ácidos nucleicos y un cambio en las propiedades estructurales de las proteínas son los principales factores que inducen la depuración. Al mismo tiempo, la estabilidad molecular del colágeno en condiciones alcalinas permite que la muestra mantenga su forma después del proceso.

Evaluation of simulation models in neurosurgical training according to face, content, and construct validity: a systematic review.

BACKGROUND: Neurosurgical training has been traditionally based on an apprenticeship model. However, restrictions on clinical exposure reduce trainees' operative experience. Simulation models may allow for a more efficient, feasible, and time-effective acquisition of skills. Our objectives were to use face, content, and construct validity to review the use of simulation models in neurosurgical education. METHODS: PubMed, Web of Science, and Scopus were queried for eligible studies. After excluding duplicates, 1204 studies were screened. Eighteen studies were included in the final review. RESULTS: Neurosurgical skills assessed included aneurysm clipping (n = 6), craniotomy and burr hole drilling (n = 2), tumour resection (n = 4), and vessel suturing (n = 3). All studies assessed face validity, 11 assessed content, and 6 assessed construct validity. Animal models (n = 5), synthetic models (n = 7), and VR models (n = 6) were assessed. In face validation, all studies rated visual realism favourably, but haptic realism was key limitation. The synthetic models ranked a high median tactile realism (4 out of 5) compared to other models. Assessment of content validity showed positive findings for anatomical and procedural education, but the models provided more benefit to the novice than the experienced group. The cadaver models were perceived to be the most anatomically realistic by study participants. Construct validity showed a statistically significant proficiency increase among the junior group compared to the senior group across all modalities. CONCLUSION: Our review highlights evidence on the feasibility of implementing simulation models in neurosurgical training. Studies should include predictive validity to assess future skill on an individual on whom the same procedure will be administered. This study shows that future neurosurgical training systems call for surgical simulation and objectively validated models.

Viability and characterization trial of a novel method as an alternative to formaldehyde and Walter-Thiel cadaveric preservation for medical education and surgical simulation.

INTRODUCTION: Despite its toxic and carcinogenic nature, formaldehyde is a widely used reactant for specimen preservation. With the need of specimens for both anatomical and surgical training, alternative preservation solutions (PS) have been proposed, however, their use is limited due to high costs and complexity. Hence, a new formaldehyde-free solution (FFS) is evaluated as a potential alternative for anatomical and surgical training. METHODS: Qualitative and Quantitative data were acquired. Specimens preserved using three different methods were selected. Flexibility was measured by joints goniometry and pneumoperitoneum pressures were evaluated followed by an exploratory laparoscopy. Undergraduate student's perceptions on cadavers preserved with different PS were obtained using surveys and focus groups. RESULTS: The main reason why cadaveric specimens were considered as useful tools was the perceived interaction with real tissues and the 'practical' concept of getting in touch with what students would be facing in the future as physicians, what we call "hands on" activities. FFS treated specimens showed better joint-movement ranges in comparison to other methods and pneumoperitoneum was acquired after 5mmHg CO2 pressure. Students appreciated working with corpses regardless the technique used, however FFS specimens were defined as less uncomfortable, while presenting no sensory discomfort. CONCLUSIONS: Even though alternative PS are effective, high costs and complexity restrict their usage. Cadavers preserved with FFS had similar range of movements compared with Thiel. Students preferred to work with FFS rather than FF due to flexibility, color, and no sensorial hassles. Thus, we propose FFS as viable alternative to traditional PS.

Outcomes of 207 totally extraperitoneal hernia repairs using self-fixation mesh.

Inguinal hernia (IH) repair is one of the most common procedures in general surgery around the world. Minimizing postoperative acute and chronic pain without increasing recurrence has been a critical point, giving place to different strategies like self-fixation mesh. The current study aimed to describe a group of patients who underwent IH repair by Totally Extraperitoneal (TEP) technique with self-gripping mesh at a fourth level hospital between 2012 and 2019. Retrospective review of a prospectively collected database including patients who underwent laparoscopic TEP approach with self-fixation mesh for IH repair. Follow up data was obtained at 12, 24, 36, 48, and 60 months post surgical intervention. 207 hernia repairs were performed in 142 patients, with a total of 66 patients with bilateral IH. 10.6% required hospitalization due to either concomitant procedure performed or cardiovascular comorbidities, with a mean hospital stay of 1.6 days. Median and late follow up was up to 5 years. 88.9% of patients complete a year, 86% two years, and 36.7% with a 5 year follow-up. IH repair using the TEP technique and self-fixation mesh showed to be an excellent approach, demonstrating satisfactory results in follow up and complications.

Hill Modified, a Novel Approach: Technique Description and Experience in Patients with Laparoscopic Sleeve Gastrectomy.

BACKGROUND: Gastroesophageal reflux disease (GERD) is a common disease among patients with obesity, with an associated prevalence of 39 to 61% between the population who attends a bariatric surgery evaluation. Laparoscopic sleeve gastrectomy (LSG) has become a popular and valid option for obesity treatment, even though the literature is ambivalent regarding the increase or decrease in GERD after this surgery. Thus, it is necessary to propose new surgical techniques as a solution to GERD in patients with a concomitant LSG or with a history of it. Therefore, we present a modified technique based on Hill's gastropexy described originally in 1967. OBJECTIVE: Describe and propose a surgical procedure for GERD management based on the Hill technique that can be applied in all patients who undergo an LSG or with a history of it. METHODS: Retrospective observational study with a prospective database in which we described, Hill modified technique in a group of 16 patients with GERD who underwent this procedure concomitantly with an LSG or who presented with GERD after LSG with a 3-year follow-up. The surgical technique is based on an intra-abdominal esophageal length of a minimum of 3 cm and posterior fixation of the gastroesophageal junction to the crus. RESULTS: Postoperative controls have shown satisfactory results in the control and management of GERD symptoms in this group of patients, with very few to no complications associated with the procedure and without reintervention or medication out of the standard protocol. CONCLUSION: Hill modified technique can be used and presented as an option for GERD control in patients with LSG.

Spontaneous splenic rupture in a patient with chronic myeloid leukemia: A case report.

INTRODUCTION: Spontaneous splenic rupture is an atraumatic event that represents a rare and life-threatening acute complication in which the spleen is damaged producing internal hemorrhage in the abdominal cavity. Its association with hematologic malignancies, although a rare occurrence, has been previously described. Among this subset of patients, chronic myeloid leukemia is one of the main causes. PRESENTATION OF CASE: A 26-year-old male with history of chronic myeloid leukemia presented with acute intense abdominal right lower quadrant pain. Computed tomography showed a wedge in the lower third of the spleen (probably associated with infarction), active bleeding, and hemoperitoneum. Laparotomy and splenectomy were performed. DISCUSSION: The most common symptom of spontaneous splenic rupture is acute abdominal pain, sometimes radiating to the left shoulder. It can also be associated with nausea, emesis and signs of hypovolemia or shock. Splenomegaly may be absent. Diagnostic methods of choice are computed tomography and ultrasound. Management of splenic rupture is divided in surgical and conservative. The former is reserved for patients with extensive splenic injury that is accompanied by hemodynamic instability or other trauma that warrants surgical treatment. Patients who do not meet these criteria and respond to initial stabilization strategies can be offered clinical and laboratory monitoring. Stable patients with moderate to severe splenic injuries can be offered angioembolization. CONCLUSION: It is important to include splenic rupture as a differential diagnosis for acute abdominal pain, especially in patients with hematologic malignancy, since early recognition and treatment increases patient survival and improves prognosis.

Aneurysmal Subarachnoid Hemorrhage Associated with Small Aneurysms in Smokers and Women: A Retrospective Analysis.

BACKGROUND: Previous studies have shown low rupture rates for small aneurysms (<10 mm), suggesting that the risk of treatment could exceed the benefits. However, evidence has changed, showing crescent rates of aneurysmal subarachnoid hemorrhage (aSAH) associated with small aneurysms. We report trends in size, localization, clinical characteristics, and outcomes of intracranial aneurysms (IAs). METHODS: In this retrospective study, a total of 200 clinical histories of patients diagnosed with IAs over an 8-year period were analyzed. Variables considered included age, sex, tobacco consumption, morphological characteristics of the aneurysm, complications, vasospasm, and mortality. Qualitative variables were assessed by measurements of absolute and relative frequency. Smoking behavior, aneurysm size, and aneurysm rupture (AR) were compared using 1-way analysis of variance. Categorical variables were analyzed using Pearson's χ2 test. RESULTS: The average age at presentation was 58 years. The average size of ruptured aneurysms in the general group was 2.5-7.5 mm, and AR was most common in women (76%) and in patients age 50-60 years (33%). The rate of vasospasm was 19%, and mortality was 37%. Smokers composed 32% of the cohort. Heavy smokers had a 57% rate of aSAH, with an average size of rupture of 5 mm. The most common location of aneurysms and AR was the AComA (33%). CONCLUSIONS: Our results suggest increasing AR rates in aneurysms smaller than 10 mm. This trend is seen especially in individuals with heavy tobacco consumption and in women of perimenopausal age. Our findings show a tendency of AR in accordance with previous results and are expected to serve as basis for further research on aneurysm management.

An alternative method for the comparative study of coronary vessels: repletion and diaphanization experience in seven animal models / Repleción y diafanización como una alternativa para el estudio comparativo de los vasos coronarios: experiencia en siete modelos animales

Coronary arteries establish a complex blood vessel system, right and left coronary arteries commonly originate from the aortic sinuses and divide into multiple branches that supply the heart with several important variations between species. Diaphanization is a preservative technique which allows internal structures visualization, maintaining the three-dimensionality of the specimen. In this study, human (Homo sapiens), goat (Capra aegagrus hircus), bovine (Bos Taurus), equine (Equus caballus), porcine (Sus scrofa domesticus), canine (Canis lupus familiaris) and feline (Felis silvestris catus) coronary arteries were injected with selfcuring methyl-methacrylate and posteriorly diaphanized. The coronary vasculature was adequately observed in all models while keeping the three-dimensional relation with surrounding cardiac structures, except for septal arteries which were not visualized. As incidental findings, anatomical variations in canine and human hearts were observed. Repletion-diaphanization is a useful blended method to visualize the morphology of superficial coronary arteries. It could be a valuable tool in anatomical teaching and research, but further research needs to be done to prove its effectiveness in different vessel systems.

Las arterias coronarias son un complejo de vasos sanguíneos que usualmente se originan en los senos aórticos y que al dividirse en múltiples ramas suplen los requerimientos metabólicos del tejido cardiaco; cabe aclarar que la anatomía de estas estructuras posee variaciones importantes entre especies. La diafanización es una técnica de preservación que permite observar estructuras internas de un espécimen sin dañar su tridimensionalidad. En este estudio las arterias coronarias del corazón humano (Homo sapiens), caprino (Capra aegagrus hircus), bovino (Bos Taurus), equino (Equus caballus), porcino (Sus scrofa domesticus), canino (Canis lupus familiaris) y felino (Felis silvestris catus), fueron repletadas con metil-metacrilato y posteriormente diafanizados. Se observa la irrigación coronaria de cada uno de los corazones y su relación con las demás estructuras cardiacas, exceptuando las arterias septales. Como hallazgos incidentales se observaron variaciones anatómicas en los corazones canino y humano. Finalmente, esta técnica resultó de utilidad para evaluar la anatomía coronaria, lo que puede ser valioso para educación e investigación. Posteriores investigaciones deben ser realizadas para probar su utilidad en otros sistemas vasculares.

Corrosion casting, a known technique for the study and teaching of vascular and duct structure in anatomy / Inyección corrosión, una técnica conocida para el estudio y enseñanza de ductos y estructuras vasculares en anatomía

Teaching and learning anatomy, as a process, has changed. Fresh cadavers were once used as a tool for the student to approach the human body in order to overcome theoretical knowledge and gain applied expertise. Today, techniques such as corrosion casting are known to be a more effective way of achieving optimal results with the students. This paper examines a method to apply this technique to an organ using different polymers. The concentrations for acrylic, epoxy resin, polyester resin, and room temperature vulcanization (RTV) silicone are described, as well as the corresponding diameter of the duct to be injected with each one. A variety of specimens obtained using this technique, their qualities and characteristics are presented. The results of using these procedures while involving the students, showed increased sense of responsibility, dedication and awareness, which led them to take the class more seriously and enjoy the process of learning. Additionally, the specimens left by the students will help future classes reduce the number of specimens needed.

El proceso de aprendizaje y enseñanza en anatomía ha cambiado recientemente, el cadáver fue la primera herramienta que permitía al estudiante una aproximación practica al cuerpo humano, facilitando que este se sobrepusiera al conocimiento teórico adquirido en el aula, y desarrollara experticia aplicada. Hoy en día, técnicas como la inyección corrosión son conocidas por lograr mejores resultados con los estudiantes. Este trabajo presenta un método para aplicar esta técnica a un órgano, mediante el uso de diferentes polímeros. Las concentraciones adecuadas de acrílico, resina epoxica, resina poliéster, y silicona RTV (room temperature vulcanization) son descritas, así como el diámetro sugerido para el uso de cada polímero. Se presenta una variedad de especímenes obtenidos mediante esta técnica, así como sus cualidades y características. Al integrar a los estudiantes en el proceso de creación de los especímenes, estos demuestran mayor sentido de responsabilidad, dedicación y autoconciencia, generando mayor compromiso, y entusiasmo con la clase y el proceso de aprendizaje. Adicionalmente, los especímenes producidos por ellos, serán de gran utilidad para clases a futuro.

Multiple software based 3D modeling protocol for printing anatomical structures / Protocolo de impresión 3D de estructuras anatómicas basados en la utilización de software múltiple

With the increasing number of medical programs, research for new teaching methods has also emerged. Computer software and diagnostic images have been used for anatomy teaching as an alternative to cadaver dissection, which means students cannot develop a mental image of the human body without compromising spatial reasoning. Also the cadavers present flaws such as color, texture and smell. This paper explains in details the protocol used to reconstruct 3D models for rapid prototyping as an overcome to these difficulties. Online Computerized Tomography scans were obtained in DICOM format from OsiriX and InVesalius. Reconstruction of 3D models from aortic and superior tracheobronchial tract structures were created, InVesalius and Rhinoceros software were used. 3D models of a heart with its aorta, superior tracheobronchial tract and an aneurysm at the aortic bifurcation were obtained for rapid prototyping. The superior tracheobronchial tract model was printed. It is possible to produce printed models from CT scans using different softwares for 3D modeling and rapid prototyping. These models could allow the student to develop a three dimensional mental image of the human body according to literature.

Con el incremento en el número de programas médicos, la búsqueda por nuevos métodos de enseñanza también ha emergido. Software computarizado e imágenes diagnósticas han sido utilizados en la enseñanza de anatomía como una alternativa a la disección cadavérica, lo que conlleva a que los estudiantes no puedan desarrollar una imagen mental del cuerpo humano sin comprometer el raciocinio espacial. También los cadáveres presentan desventajas como color, textura y olor. Este artículo explica en detalle el protocolo usado para la reconstrucción de modelos 3D para prototipado rápido como un recurso para superar estas dificultades. Tomografías computarizadas online fueron obtenidas en formato DICOM de OsiriX e InVesalius. La reconstrucción en 3D de modelos de estructuras aórticas y del ducto traqueobronquial fueron creadas con los software InVesalius y Rhinoceros. Modelos 3D de corazón y aorta, el ducto traqueobronquial y un aneurisma aórtico abdominal en su bifurcación fueron obtenidos para la prototipado rápido. El modelo de ducto traqueobronquial fue impreso. Es posible producir modelos de TC usando diferentes programas de modelado 3D. Estos modelos podrían permitir a los estudiantes desarrollar una imagen metal tridimensional del cuerpo humano según la literatura.

Diaphanization: a standardized protocol for non-fetal tissue preservation / Diafanización: un protocolo estandarizado para la preservación de tejido adulto

In response to the arising difficulty of dissection use during anatomy courses, medical schools have been forced to research alternative teaching methods. These are meant to help students develop three dimensional mental images of the human body and increase spatial reasoning, thus improving the learning process of human morphology. One of those methods, used at the Universidad de los Andes is the Diaphanization process. This technique is a well-known method for specimen preservation, used as an anatomy research and teaching tool. Even though it is frequently used, finding a standardized protocol in indexed journals is not possible, which hinders the use of the technique. The standardization of an updated protocol is a need in order to continue exploiting the maximum educational capacity of the specimens used during classwork. The process used at the Universidad de los Andes for non-fetal tissue preservation by Diaphanization is described, with a detailed explanation of its five main stages: Injection, Fixation, Dehydration, Bleaching (or Maceration) and Final preservation. The final result should be an organ preserved in an acrylic box which allows clear three dimensional visualization of anatomical structures that can be used for the study and description of general anatomy and vascular structure. It also helps with spatial reasoning and represents little to no biological risk, leading to a new level of anatomical teaching and experimenting. Several specimens obtained at our laboratory through this technique are presented.

Como respuesta a la dificultad del uso de disección como una herramienta en el curso de anatomía, las escuelas de medicina se han visto forzadas a investigar y desarrollar métodos alternativos que la reemplacen. Estos pretenden estimular el desarrollo de la percepción tridimensional de los estudiantes, logrando mejor racionamiento espacial, y así, mejorando el proceso de aprendizaje de la morfología humana. Uno de estos métodos, en uso en la Universidad de los Andes, es el proceso de diafanización. Esta técnica es ampliamente conocida en el ámbito de preservación de tejidos, y empleada en investigación y educación. Aún con su uso frecuente, un protocolo estandarizado que la describa no está disponible en la literatura indexada, lo cual limita su uso. La estandarización de un protocolo actualizado es necesaria para permitir el continuo uso de esta técnica. Se describe el proceso de preservación de tejido adulto mediante la diafanización, con una explicación detallada de los 5 pasos que la componen: Inyección, Fijación, Deshidratación, Macerado y Preservación final. El resultado es un órgano inmerso en glicerina en un contenedor de acrílico que permite una visualización tridimensional de las estructuras anatómicas del espécimen, que puede ser empleado por los estudiantes para su estudio, y permite una descripción de la anatomía general del modelo y su estructura vascular. Adicionalmente incrementa el razonamiento espacial de los estudiantes, y no presenta ningún riesgo biológico. Se presentan una variedad de especímenes de características particulares obtenidos mediante la aplicación de esta técnica.

Morphometric study of five constant skull base foramina in the Muisca population of the Tibanica anthropological collection of the Universidad de Los Andes / Estudio morfométrico de cinco forámenes constantes de la base del cráneo en la población Muisca de la colección antropológica Tibanica de la Universidad de Los Andes

Among osteological anatomic variations are those of the skull base foramina. These openings have conventionally been classified as either constant or variant. Their presence and dimensions have been associated with certain pathologies and procedural complications. Additionally, variability in these foramina between different ethnic groups has been observed, and it is sometimes possible to identify particular patterns of variability in certain populations. This anthropometric cross-sectional study seeks to determine the principal dimensions (bilateral anteroposterior and lateromedial diameters) of five constant skull base foramina in the adult Muisca population of the Tibanica anthropological collection at Universidad de los Andes. The studied foramina were magnum, jugular, ovale, spinosum, and external opening of the carotid canal. Only dimensions of the external openings of the foramina were recorded, owing to the preservation state of the skulls in the collection. The mean left and right anteroposterior and lateromedial diameters were 3.48 mm, 6.16 mm and 3.25 mm, 6.26 mm for the foramen ovale; 2.38 mm, 2.65 mm and 2.39 mm, 2.66 mm for foramen spinosum; 8.36 mm, 15.41 mm and 8.55 mm, 15.10 mm for the jugular foramen; 5.28 mm, 6.75 mm and 5.48 mm, 6.97 mm for the external opening of the carotid canal; and 33.90 mm, 29.47 mm for the foramen magnum. All foramina were measured twice, no important differences were observed between the results obtained in the first and second measurements. The skull base foramina of the sample studied did not suggest high variability within the population regarding these characteristics. Moreover, we can state that the morphometric profile displayed by the Tibanica collection at Universidad de los Andes is different from the one observed in other populations. Additional studies of anatomic variations in indigenous populations may be needed to make possible similarities and/or differences and their causes evident.

Entre las variaciones anatómicas óseas, se consideran aquellas referentes a los forámenes de la base del cráneo. Convencionalmente, estos orificios han sido clasificados como variantes o constantes. Su presencia y dimensiones se asocian a ciertas patologías y complicaciones procedimentales. Adicionalmente, se ha observado variabilidad en estos entre distintos grupos étnicos y en algunas ocasiones es posible identificar patrones particulares en poblaciones específicas. Este estudio morfométrico de corte transversal busca determinar las dimensiones principales (diámetros anteroposterior y lateromedial) de cinco forámenes constantes de la base del cráneo en la población adulta Muisca de la colección antropológica Tibanica de la Universidad de los Andes. Los forámenes estudiados fueron: magno, yugular, ovale, espinoso y la apertura externa del canal carotideo. Debido al estado de preservación de los cráneos, se registraron las dimensiones de las aperturas externas de los forámenes. La media de los diámetros izquierdo y derecho anteroposterior y lateromedial fue 3,48 mm, 6,16 mm y 3,25 mm, 6,26 mm para el foramen ovale; 2,38 mm, 2,65 mm y 2,39 mm, 2,66 mm para el espinoso; 8,36 mm, 15,41 mm y 8,55 mm, 15,10 mm para el yugular; 5,28 mm, 6,75 mm y 5,48 mm, 6,97 mm para la apertura externa del canal carotideo; y 33,90 mm, 29,47 mm para el foramen magno. Todos los diámetros se registraron dos veces, no se observó ninguna diferencia importante entre los registros de la primera y segunda medición. En general, las dimensiones de los forámenes estudiados no varían mucho en la colección ósea Muisca de Tibanica. En cuanto a estas características anatómicas, la población utilizada es diferente con respecto a algunas modernas. Por otro lado, se requieren investigaciones adicionales de este tipo con el fin de evidenciar posibles similitudes y diferencias entre poblaciones (prehispánicas y modernas) y determinar sus causas.