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 χ 2 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.

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.

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.

BackgroundIntracranial aneurysms represent a potential risk factor for various comorbidities, mainly associated with its rupture. Available information for aneurysms intervention is changing a paradigm and now, the decision of operating or not, varies in co‐dependence with the patient. We present the preliminary results of a potential tool that shows high rupture probability areas, predicting early rupture risk, also as an alternative for surgical planning.ObjectiveTo describe the mathematical models that best characterize the blood flow in an aneurysm and implement them through computational simulations to define the hemodynamic properties in terms of pressure, velocity and shear rate in artery walls.Materials/MethodsUsing the software ITK snap, an angioscanography of a patient from the Fundación Santa Fe de Bogotá was segmented. This program implements the methodology of snake evolution to obtain a 3D model by creating an estimated anatomical form and calculating internal forces of the image gradient inside of a closed curve. This gradient is determined by the pixel intensity on every point of the closed curve, which can be enhanced by contrast made previously to the volume. Secondly, with the purpose of having a non‐restriction model, the software Meshlab was used. This software edits and processes a model that is composed of triangular meshes. For this, a three Laplacian smooth was implemented in the final model. Finally, the blood flow within an aneurysm was modeled using the Comsol Multiphysics software assuming that blood behaves like Newtonian fluid with laminar flow, density of 1000 kg/m3 and a dynamic viscosity of 0.0035 Pa * s, governed by conservation of momentum and mass equations. For the simulation, a free tetrahedral mesh was used, with refinement at the edges of the geometry, whose size was defined by the previously established fluid dynamics.ResultsFor our first model, the highest stress levels were found at two points of an aneurysm: at the entrance and at the wall, where the highest velocity of blood flow was present. As for the velocity of the blood, it was reduced in the model, meaning that recirculation was present which is to be expected when dealing with aneurysms. Lastly, the shear rate was highest at the neck of the aneurysm and its lowest degree inside the aneurysm.DiscussionThe mathematical models describe the behavior of different variables. The simulation of blood flow within an aneurysm model obtained from diagnostic images of a real patient generates a good approximation to the behavior of blood flow in real life.ConclusionPressure, speed and shear stress on the arterial wall are the main factors involved in the development and possible rupture of an aneurysm. The mathematical models of this preliminary study will be implemented on a larger database. By doing so, a method capable of predicting the point in which there is a greater probability of rupture in an aneurysm can be developed, based on its hemodynamic properties.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Plastination as a technique creates durable, long lasting, realistic specimens with a high value in anatomy teaching and research. While the original protocol using Acetone has shown great results, the use of this substance is restricted in some countries due to socioeconomical or governmental limitations. The aim of this work is to develop a protocol in which acetone has been replaced as a dehydration and defatting medium. Three groups of specimens were procured. Each of them had a sample of abdominal organs with varying fragility (kidney‐liver‐small intestine), skeletal muscle and brain tissue. Group 1 and 2 (G1–G2) were previously fixated with formaldehyde 4%, while group 3 (G3) was preserved in a glycerin‐based formaldehyde free solution. A conventional plastination technique was carried out including fixation, dehydration, defatting, forced impregnation and curing. All groups were fixated with formaldehyde 10%, although G3 required cleansing with a 50% ethylic alcohol (EA) solution to remove the glycerin. G1 was dehydrated and defatted with EA. G2 & G3 were dehydrated with isopropyl alcohol (IA), and defatted with methylene chloride (MC). All groups were impregnated in low temperatures with 1% S3–S10 Biodur silicone‐cross linker mixture. Finally, curing was divided in two steps, passive curing for 6 months and S6 cross linking. The specimens were analyzed based on tissue retraction, color degradation, morphological alterations and final specimen pliability. G1 showed maximum tissue shrinkage, morphological alteration and color degradation acquiring a brownish tone. G2 & G3 suffered less tissue retraction, color degradation was minimal, morphological alteration was not observed. Specimen pliability remained the same across the three groups, specific tissues such as skeletal muscle, blood vessels and intestine were more pliable. Lesser tissue retraction and increased color preservation were obtained with the use of IA and MC for dehydration and defatting, compared with exclusive use of EA for both steps. Specimens previously preserved with glycerin‐based formaldehyde free solutions where successfully plastinated with this technique. While this study serves as a proof of concept that IA and MC are viable substitutes for Acetone in the dehydration and defatting steps, the lack of objective measurements and a control group with acetone are strong limitations of this study. Future studies with a higher number of standardized specimens and controls are needed to determine the impact of the proposed replacement in the plastination protocol.