Revisión sistemática de las aplicaciones y límites de la impresión 3D en la cirugía de raquis / Systematic review of the utility and limits of 3D printing in spine surgery

Objetivo: El objetivo principal de este estudio ha sido demostrar por qué la impresión aditiva permite hacer más visibles y entendibles los procesos patológicos quirúrgicos complejos que afectan al raquis, aumentando la precisión, la seguridad y la fiabilidad del procedimiento quirúrgico.MetodologíaSe realizó una revisión sistemática de los trabajos publicados en los últimos 10 años, sobre la cirugía de raquis asistida por impresión 3D, de acuerdo con la declaración PRISMA 2020. Con las palabras clave «printing 3D» y «spine surgery» se hicieron búsquedas en las bases de datos Pubmed, Embase, Cochrane Database of Systematic Reviews, Google Scholar y Opengrey, que se completó con la búsqueda manual a través de la lista de referencias bibliográficas de los artículos que fueron seleccionados siguiendo los criterios de inclusión y exclusión definidos.ResultadosDel análisis de los 38 estudios seleccionados resultó que la impresión 3D es útil en la planificación quirúrgica, en la enseñanza médica, en la relación médico-paciente, así como en el diseño de plantillas de navegación e implantes de raquis y, en investigación, ofreciendo un magnífico apoyo al proceder quirúrgico.ConclusionesEl uso de biomodelos impresos de forma tridimensional permite: hacer más visibles y entendibles los procesos patológicos quirúrgicos complejos que afectan al raquis; aumentar la exactitud, precisión y seguridad del procedimiento quirúrgico; y abrir la posibilidad de poner en práctica tratamientos personalizados, fundamentalmente en la cirugía tumoral. (AU)

Objective: The main objective of this study has been to demonstrate why additive printing allows to make complex surgical pathological processes that affect the spine more visible and understandable, increasing precision, safety and reliability of the surgical procedure.MethodsA systematic review of the articles published in the last 10 years on 3D printing-assisted spinal surgery was carried out, in accordance with PRISMA 2020 declaration. Keywords «3D printing» and «spine surgery» were searched in Pubmed, Embase, Cochrane Database of Systematic Reviews, Google Scholar and Opengrey databases, which was completed with a manual search through the list of bibliographic references of the articles that were selected following the defined inclusion and exclusion criteria.ResultsFrom the analysis of the 38 selected studies, it results that 3D printing is useful in surgical planning, medical teaching, doctor–patient relationship, design of navigation templates and spinal implants, and research, optimizing the surgical process by focusing on the patient, offering magnificent support during the surgical procedure.ConclusionsThe use of three-dimensional printing biomodels allows: making complex surgical pathological processes that affect the spine more visible and understandable; increase the accuracy, precision and safety of the surgical procedure, and open up the possibility of implementing personalized treatments, mainly in tumor surgery. (AU)

[Translated article] Mechanical resistance of polylactic acid bone matrices developed by 3D printing for the reconstruction of bone defects.

INTRODUCTION: Bone defects are one of the main limitations in orthopaedic surgery and traumatology. For this reason, multiple bone replacement systems have been developed, either by prosthetic implant or by substitution with osteoforming substances, whose limitations are their survival and lack of structurality, respectively. The objective of this work is the generation of a new material for the creation of biologically active structures that have sufficient tensile strength to maintain the structure during remodelling. MATERIAL AND METHODS: A new filament based on the fusion of natural polylactide acid (PLA) powder was designed for the generation of pieces by means of fused deposition modelling (FDM) on which to carry out tensile mechanical tests of osteosynthesis material. A total of 13 groups with different cortical thickness, filling and layer height were carried out, with 10 tensile tests in each group, defining the tensile breaking limit for each group. The regression lines for each group and their mechanical resistance to traction on the filament used were determined. RESULTS: The filament ratio per contact surface unit with the osteosynthesis used was the main determinant of the mechanical resistance to traction, either at the expense of the increase in cortical thickness or by the increase in the percentage of cancellous bone filling. Layer height had a minor effect on tensile strength. The regression value was high for cortical thickness and cancellous filling, being elements with a predictable biomechanical behaviour. CONCLUSIONS: The new methodology allows the creation of personalised neutral and implantable PLA bone matrices for the reconstruction of large bone defects by means of 3D printing by FDM with a mechanical resistance to traction greater than that of current biological support structures.

Systematic review of the utility and limits of 3D printing in spine surgery.

OBJECTIVE: The main objective of this study has been to demonstrate why additive printing allows to make complex surgical pathological processes that affect the spine more visible and understandable, increasing precision, safety and reliability of the surgical procedure. METHODS: A systematic review of the articles published in the last 10 years on 3D printing-assisted spinal surgery was carried out, in accordance with PRISMA 2020 declaration. Keywords "3D printing" and "spine surgery" were searched in Pubmed, Embase, Cochrane Database of Systematic Reviews, Google Scholar and Opengrey databases, which was completed with a manual search through the list of bibliographic references of the articles that were selected following the defined inclusion and exclusion criteria. RESULTS: From the analysis of the 38 selected studies, it results that 3D printing is useful in surgical planning, medical teaching, doctor-patient relationship, design of navigation templates and spinal implants, and research, optimizing the surgical process by focusing on the patient, offering magnificent support during the surgical procedure. CONCLUSIONS: The use of three-dimensional printing biomodels allows: making complex surgical pathological processes that affect the spine more visible and understandable; increase the accuracy, precision and safety of the surgical procedure, and open up the possibility of implementing personalized treatments, mainly in tumor surgery.

Microtensile bond strength of resin cements to 3-D printed and milled temporary restorative resins / Resistencia de unión en microtracción de cementos resinosos a resinas para provisionales impresas y fresadas

Abstract To evaluate the microtensile bond strength (µTBS) of two resin cements to 3D printed and milled CAD/CAM resins used for provisional fixed partial dentures. Blocks (5 x 5 x 5 mm) of three 3D-printed resins (Cosmos3DTemp / Yller; Resilab3D Temp / Wilcos and SmartPrint BioTemp, / MMTech) were printed (Photon, Anycubic Technology Co.). A milled material (VitaCAD-Temp, VITA) was used as control. Half the specimens were sandblasted and the rest were untreated. Two blocks were bonded with the corresponding resin cement: PanaviaV5 (Kuraray Noritake) and RelyX Ultimate (3M Oral Care). After 24 hours, the bonded blocks were sectioned into 1 x 1 mm side sticks. Half the beams were tested for µTBS and the other half was thermocycled (5000 cycles, 30s dwell-time, 5s transfer time) before µTBS testing. A four way Generalized Linear Model (material*sandblasting*cement*aging) analysis was applied. VITA exhibited the lowest µTBS, regardless of the cement, sandblasting and thermocycling. Sandblasting significantly improved the µTBS of VIT, especially after aging, but did not improve the µTBS of 3D printed resins. Sandblasting was not beneficial for 3D printed resins, although is crucial for adhesive cementation of milled temporary resins. Airborne particle abrasion affects the integrity of 3D-printed resins, without producing a benefit on the microtensile bond strength of these materials. However, sandblasting is crucial to achieve a high bond strength on milled temporary resins.

Resumen Evaluar la resistencia adhesiva en microtracción (µTBS) de dos cementos resinosos a resinas CAD/CAM impresas y fresadas indicadas para restauraciones provisionales. Bloques (5 x 5 x 5mm) de tres resinas impresas (Cosmos3DTemp / Yller; Resilab3D Temp / Wilcos and SmartPrint BioTemp, / MMTech) y una resina fresada (VitaCAD-Temp, VITA) fueron fabricados. La mitad de los especímenes fueron arenados y el resto no recibió tratamiento mecánico. Dos bloques con condiciones de tratamiento iguales fueron cementados con cemento resinoso (PanaviaV5 / Kuraray Noritake y RelyX Ultimate / 3M Oral Care). Después de 24 horas los bloques fueron seccionados en palitos de 1 mm² de área. En la mitad de los especímenes se midió la TBS inmediatamente y el resto fue termociclado (5000 ciclos, 30s remojo, 5s transferencia) antes de la prueba de TBS. Se aplica un análisis estadístico por Modelo Linear General con 4 factores (material*arenado*cemento*termociclado). La resina VITA presentó la menor µTBS, independientemente del cemento usado, el arenado y el termociclado. Sin embargo, el arenado aumentó la µTBS de VIT, especialmente después del termociclado. Por otro lado, el arenado no resultó en un aumento significativo de la µTBS de las resinas impresas. El arenado no fue beneficiosos para las resinas impresas, aunque es un paso crucial para la cementación adhesive de las resinas fresadas. El arenado afecta la integridad de las capas de las resinas impresas, sin generar un beneficio en la TBS.

Anatomía de la cámara pulpar y sistema de conductos radiculares: Estrategias pedagógicas unarevisión de literatura / Anatomy of the pulp chamber and the root canal system: Pedagogical strategiesAliterature review

Antecedentes: El conocimiento anatómico de la cámara pulpar y del sistema de conductos radiculareses fundamental para el correcto diagnóstico y planificación del tratamiento en endodoncia. Las herramientas pedagógicasdirigidasa los estudiantes de odontologíacomo apoyo en los procesos formativosde la asignatura de endodoncia favorecen la apropiación del conocimiento e identificación de las variantes morfológicas del sistema de conductos radiculares, que permiten al estudiantela integración del conocimiento. Objetivo:Identificar mediante una revisión de la literatura las estrategias pedagógicas que se utilizan para la enseñanza de morfología del sistema de conductos radiculares en endodoncia. Materiales y métodos: Se realizó una búsqueda bibliográfica de estudios originales en las bases de datos Medline (Pubmed), SciELO, Lilacs, Medline (Ovid), Web of science, Scopus, Embase, Google académico, eligiendo estudios publicadosa partir del año 2010 al 2022, para la selección de los artículos definitivos se seleccionaron estudios concernientes a procesos pedagógicos en endodoncia, excluyendo así otros tipos de enfoques en el área de odontología. Resultados: Se identificaron un total de 63 referencias, los cuales fueron analizados y seleccionados16, siendo excluidos 47 por no cumplir los criterios de inclusión. Conclusión: El uso de herramientas pedagógicas virtuales, didácticas y tecnológicas propician un efecto positivo en el estudiante de pregrado de odontología durante el aprendizaje de anatomía de sistemas de conductos radiculares que aumentan la confianza y seguridad al momento de realizar un tratamiento endodóntico en pacientes

Background: Anatomical knowledge of the pulp chamber and the root canal system is essential for correct diagnosis and treatment planning in endodontics. The pedagogical tools aimed at dental students as support in the training processes of the endodontics subject favor the appropriation of knowledge and identification of the morphological variants of the root canal system, which allow the student the integration of knowledge. Objective: To identify, through a review of the literature, the pedagogical strategies used to teach morphology of the root canal system in endodontics. Materials and methods: A bibliographic search of original studies was carried out in the Medline (Pubmed), SciELO, Lilacs, Medline (Ovid), Web of Science, Scopus, Embase, and Google academic databases, choosing studies published from 2010 to 2022. , for the selection of the definitive articles, studies concerning pedagogical processes in endodontics were selected, thus excluding other types of approaches in the area of dentistry. Results: A total of 63 references were identified, 16 of which were analyzed and selected, 47 being excluded for not meeting the inclusion criteria. Conclusion: The use of virtual, didactic and technological pedagogical tools favor a positive effect on the dentistry undergraduate student while learning the anatomy of root canal systems that increase confidence and security when performing endodontic treatment in patients.

3D Printing characteristics and mechanical properties of a bio scaffold obtained from a Micro-CT Scan, using the fused deposition modeling technique

The objective is to determine which biopolymer has the best 3D printing characteristics and mechanical properties for the manufacture of a bioscaffold, using the fused deposition printing technique, with models generated from an STL file obtained from a Micro-CT scan taken from a bovine iliac crest bone structure. Through an experimental exploratory study, three study groups of the analyzed biopolymers were carried out with thirteen printed structures of each one. The first is made of 100% PLA. The second, 90B, we added 1g of diatom extract, and the third, 88C, differs from the previous one in that it also contains 1g of calcium phosphate. The 39 printed structures underwent a visual inspection test, which required the fabrication of a gold standard scaffold in resin, with greater detail and similarity to the scanned bone structure. Finally, the structures were subjected to a compressive force (N) to obtain the modulus of elasticity (MPa) and compressive strength (MPa) of each one of them. A statistically significant difference (p=0.001) was obtained in the printing properties of the biomaterial 88C, compared to 90B and pure PLA and the 88C presented the best 3D printing characteristics. In addition, it also presented the best mechanical properties compared to the other groups of materials. Although the difference between these was not statistically significant (p=0.388), in the structures of the 88C biomaterial, values of compressive strength (8,84692 MPa) and modulus of elasticity (43,23615 MPa) were similar to those of cancellous bone in the jaws could be observed. Because of this result, the 88C biomaterial has the potential to be used in the manufacture of bioscaffolds in tissue engineering.

El objetivo es determinar cuál biopolímero presenta las mejores características de impresión 3D y propiedades mecánicas para la fabricación de un bioandamiaje, utilizando la técnica de impresión por deposición fundida, con modelos generados a partir de un archivo en formato STL que se obtuvo de un Micro-CT Scan de una estructura osea de cresta iliaca bovina. Mediante un estudio exploratorio, se realizaron 3 grupos de estudio con trece estructuras impresas de cada uno. El primero, se compone 100% de PLA. El segundo, 90B, se le agrega 1g de extracto de diatomea, y el tercero, 88C, se diferencia del anterior ya que contiene además, 1g de fosfato de calcio. A las 39 estructuras impresas se les realizó una prueba de inspección visual, por lo que se requirió la confección de un patrón de oro en resina, con mayor detalle y similitud a la estructura ósea escaneada. Finalmente, las estructuras fueron sometidas a una fuerza compresiva (N) para la obtención del módulo de elasticidad (MPa) y de la resistencia compresiva (MPa) de cada una de ellas. Se obtuvo una diferencia estadísticamente significativa (p=0,001) en las propiedades de impresión del biomaterial 88C, con respecto al 90B y al PLA puro, presentando las mejores características de impresión 3D. Además, obtuvo las mejores propiedades mecánicas en comparación con los otros grupos de materiales. Aunque la diferencia entre estos no fue estadísticamente significativa (p=0,388), en las estructuras del biomaterial 88C, se pudieron observar valores de resistencia compresiva (8,84692 MPa) y módulo de elasticidad (43,23615 MPa) que son semejantes a los del hueso esponjoso de los maxilares. A razón de este resultado, el biomaterial 88C cuenta con el potencial para ser utilizado en la fabricación de bioandamiajes en la ingeniería tisular.

Randomized clinical trial on the usefulness of 3D printing in intra-articular fractures of the distal radius. / Ensayo clínico aleatorizado sobre la utilidad de la impresión 3D en las fracturas intraarticulares de radio distal.

OBJECTIVES: We evaluated the utility of 3D printing technology for preoperative planning in the treatment of intra-articular fractures of the distal radius in relation to the improvement of surgical technique, radiological and clinical results. MATERIAL AND METHODS: A total of 30 patients with 2B and C fractures of the AO classification were operated on by a single surgeon with a volar plate, randomly divided into two groups, 15 of them with conventional planning (Rx and CT) and 15 adding a 3D model of the fracture and the previous simulation of the intervention. Simulation time, surgical time in minutes, radioscopy time in minutes, loss of material expressed in lost screws were recorded. Clinical evaluation based PRWE questionnaire and full radiographic analysis was done for all patients with a mean follow-up of 6 months by an independent, blinded observed. RESULTS: No statistically significant differences were observed in the PRWE questionnaire (p=0.22), nor were we observed differences in the radiological values, except in relation to the articular step (p=0.028), which represents statistical significance, but in both groups the median was of 0.0 (0.0-0.0). We also did not see statistically significant differences in surgical times (p=0.745), radioscopy (p=0.819) or in the loss of synthesis material (p=0.779). CONCLUSIONS: 3D printing has not improved the parameters studied in relation to routinely operated patients.

Nuevos Recursos Digitales y 3D en la Enseñanza de Anatomía. Experiencia Internacional Reportada en el "Sectra Users Meeting 2019", Karolinska Institutet, Suecia, antes de la Pandemia de COVID-19 / New Digital and 3D Resources in the Teaching of Anatomy. International Experience Reported in the "Sectra Users Meeting 2019", Karolinska Institutet, Sweden, Before the Pandemic COVID-19

El uso de nuevos recursos tecnológicos en la enseñanza de anatomía ha impulsado la necesidad de adaptar el modelo educativo haciéndolo más centrado en el estudiante, dinámico y participativo mediante herramientas digitales y 3D; orientando los conocimientos hacia su aplicación clínica, pero bajo un ajuste curricular que tiende a cursar menos horas presenciales en aula o laboratorio. Este trabajo describe la experiencia local de una nueva Escuela de Medicina en Chile, reportada el año 2018, además y otros trabajos de centros formadores presentados en el "SECTRA Users Meeting 2019 Estocolmo", Karolinska Institutet, Suecia. Este trabajo describe los reportes orales sobre la aplicación de nuevos recursos digitales como; la mesa de disección digital táctil SECTRA® y modelos anatómicos cadavéricos impresos en 3D Erler-Zimmer®, bases de datos sobre anatomía digital, además, su impacto en el desempeño académico, reportado por usuarios de diferentes países, tales como: Australia, Canadá, Chile, China, Colombia, Estados Unidos de Norteamérica (EUA) y Suecia. Los datos fueron recopilados y analizados a partir de la información reportada en las presentaciones orales y resúmenes entregados por los expositores. La gran mayoría de los países expositores declararon el uso combinado de recursos digitales y 3D sumados a los tradicionales para la enseñanza de anatomía. Sólo el representante de EUA declaró usar exclusivamente recursos digitales (en laboratorio y en línea), experiencia correspondiente a una joven e innovadora escuela de medicina. La mayoría de los centros docentes declaró utilizar la mesa de disección digital en una amplia proporción de sus contenidos curriculares, en asociación a plataformas tipo RIS/PACS como IDS7 portal de SECTRA o las utilizadas por el centro formador. El uso de nuevas tecnologías digitales y 3D ha ganado un importante espacio en el currículum de la enseñanza de anatomía, complementando el uso de los recursos tradicionales.

SUMMARY: The use of new technological resources in the teaching of anatomy has promoted the need to adapt the educational model, making it more student-centered, dynamic, and participatory through digital and 3D tools, directing the knowledge towards its clinical application, but under a curricular adjustment that tends to take fewer contact hours in the classroom or laboratory. This work describes the local experience of a new School of Medicine in Chile, reported in 2018, and other work from training centers presented at the "SECTRA Users Meeting 2019 Stockholm", Karolinska Institutet, Sweden. This work describes the oral reports on the application of new digital resources such as; the SECTRA® digital tactile dissection table and Erler- Zimmer® 3D printed cadaveric anatomical models, databases on digital anatomy, in addition, its impact on academic performance, reported by users from different countries, such as Australia, Canada, Chile, China, Colombia, United States of America (USA) and Sweden. The data was collected and analyzed from the information reported in the oral presentations and summaries delivered by the speakers.The vast majority of the exhibiting countries declared the combined use of digital and 3D resources added to the traditional ones for teaching anatomy. Only the representative from the USA stated that they exclusively used digital resources (in the laboratory and online), an experience corresponding to a young and innovative medical school. Most of the educational centers stated that they used the digital dissection table in a large proportion of their curricular contents, in association with RIS/PACS-type platforms such as the IDS7 SECTRA portal or those used by the training center. The use of new digital and 3D technologies has gained an important space in the anatomy teaching curriculum, complementing the use of traditional resources.

Mechanical resistance of polylactic acid bone matrices developed by 3D printing for the reconstruction of bone defects. / Resistencia mecánica de matrices óseas de ácido poliláctico desarrolladas por impresión 3D para la reconstrucción de defectos óseos.

INTRODUCTION: Bone defects are one of the main limitations in orthopedic surgery and traumatology. For this reason, multiple bone replacement systems have been developed, either by prosthetic implant or by substitution with osteoforming substances, whose limitations are their survival and lack of structurality, respectively. The objective of this work is the generation of a new material for the creation of biologically active structures that have sufficient tensile strength to maintain the structure during remodeling. MATERIAL AND METHODS: A new filament based on the fusion of natural polylactide acid (PLA) powder was designed for the generation of pieces by means of fused deposition modeling (FDM) on which to carry out tensile mechanical tests of osteosynthesis material. A total of 13 groups with different cortical thickness, filling and layer height were carried out, with 10 tensile tests in each group, defining the tensile breaking limit for each group. The regression lines for each group and their mechanical resistance to traction on the filament used were determined. RESULTS: The filament ratio per contact surface unit with the osteosynthesis used was the main determinant of the mechanical resistance to traction, either at the expense of the increase in cortical thickness or by the increase in the percentage of cancellous bone filling. Layer height had a minor effect on tensile strength. The regression value was high for cortical thickness and cancellous filling, being elements with a predictable biomechanical behavior. CONCLUSIONS: The new methodology allows the creation of personalized neutral and implantable PLA bone matrices for the reconstruction of large bone defects by means of 3D printing by FDM with a mechanical resistance to traction greater than that of current biological support structures.

Prototyping and 3D printing of computed tomography images with an emphasis on soft tissues, especially muscles, for teaching human anatomy / Prototipado e impresión 3D de imágenes de tomografía computarizada con énfasis en los tejidos blandos, especialmente músculos, para la enseñanza de la anatomía humana

SUMMARY: The study on cadavers, although considered fundamental in the teaching of human anatomy, is limited in several universities, mainly due to the acquisition and manipulation of cadaveric material. Throughout history, several artificial anatomical models have been used to complement the real anatomical pieces. The present study offers a new alternative: the making of three-dimensional models from Computed Tomography (3D-CT) patient image acquisition. CT images from the USP University Hospital database were used. Patients underwent examinations for reasons other than the present study and were anonymized to maintain confidentiality. The CT slices obtained in thin cross-sections (approximately 1.0 mm thick) were converted into three-dimensional images by a technique named Volume Rendering for visualization of soft tissue and bone. The reconstructions were then converted to an STL (Standard Triangle Language) model and printed through two printers (LONGER LK4 Pro® and Sethi S3®), using PLA and ABS filaments. The 3D impressions of the thigh and leg muscles obtained better visual quality, being able to readily identify the local musculature. The images of the face, heart, and head bones, although easily identifiable, although seemed to present lower quality aesthetic results. This pilot study may be one of the first to perform 3D impressions of images from CT to visualize the musculature in Brazil and may become an additional tool for teaching.

El estudio en cadáveres, a pesar de considerarse un aspecto fundamental en la enseñanza de la anatomía humana, se encuentra limitado en varias universidades, principalmente por la adquisición y manipulación de material cadavérico. A lo largo de la historia se han utilizado varios modelos anatómicos artificiales para complementar las piezas anatómicas reales. El presente estudio ofrece una nueva alternativa: la elaboración de modelos tridimensionales a partir de la adquisición de imágenes de pacientes por Tomografía Computarizada (3D-CT). Se utilizaron imágenes de TC de la base de datos del Hospital Universitario de la USP. Los pacientes se sometieron a exámenes por razones distintas al presente estudio y fueron anonimizados para mantener la confidencialidad. Los cortes de TC obtenidos en secciones transversales delgadas (aproximadamente 1,0 mm de grosor) se convirtieron en imágenes tridimensionales mediante una técnica denominada Volume Rendering para la visualización de tejido blando y hueso. Luego, las reconstrucciones se convirtieron a un modelo STL (Standard Triangle Language) y se imprimieron a través de dos impresoras (LONGER LK4 Pro® y Sethi S3®), utilizando filamentos PLA y ABS. Se obtuvo una mejor calidad visual de las impresiones 3D de los músculos del muslo y la pierna, pudiendo identificar fácilmente la musculatura local. Las imágenes de la cara, el corazón y los huesos de la cabeza, aunque fácilmente identificables, parecían presentar resultados estéticos de menor calidad. Este estudio piloto puede ser uno de los primeros en realizar impresiones 3D de imágenes de TC para visualizar la musculatura y podría ser en una herramienta adicional para la enseñanza.

Prototyping and 3D printing of computed tomography images with an emphasis on soft tissues, especially muscles, for teaching human anatomy / Prototipado e impresión 3D de imágenes de tomografía computarizada con énfasis en los tejidos blandos, especialmente músculos, para la enseñanza de la anatomía humana

The study on cadavers, although considered fundamental in the teaching of human anatomy, is limited in several universities, mainly due to the acquisition and manipulation of cadaveric material. Throughout history, several artificial anatomical models have been used to complement the real anatomical pieces. The present study offers a new alternative: the making of three-dimensional models from Computed Tomography (3D-CT) patient image acquisition. CT images from the USP University Hospital database were used. Patients underwent examinations for reasons other than the present study and were anonymized to maintain confidentiality. The CT slices obtained in thin cross-sections (approximately 1.0 mm thick) were converted into three-dimensional images by a technique named Volume Rendering for visualization of soft tissue and bone. The reconstructions were then converted to an STL (Standard Triangle Language) model and printed through two printers (LONGER LK4 Pro® and Sethi S3®), using PLA and ABS filaments. The 3D impressions of the thigh and leg muscles obtained better visual quality, being able to readily identify the local musculature. The images of the face, heart, and head bones, although easily identifiable, although seemed to present lower quality aesthetic results. This pilot study may be one of the first to perform 3D impressions of images from CT to visualize the musculature in Brazil and may become an additional tool for teaching.

Modelos de simulación para entrenamiento en cirugía de hueso temporal / Temporal bone surgery simulation-training models

El fresado de hueso temporal (HT) es un desafío para los otorrinolaringólogos. Este procedimiento requiere un conocimiento detallado de esta zona anatómicamente compleja y un dominio de la técnica quirúrgica. La exposición a una mastoidectomía simple o mastoidectomía radical varía entre residentes y distintos programas de especialidad y, frecuentemente, no se cumple el número requerido para la curva de aprendizaje durante la formación. Por lo anterior, surge la necesidad de realizar simulación quirúrgica de fresado de HT. El gold standard para su entrenamiento son los modelos cadavéricos, sin embargo, su costo y baja disponibilidad representan una limitación importante. Los modelos de simulación no cadavéricos podrían jugar un rol importante en el entrenamiento de esta cirugía. Se realizó una revisión exhaustiva de la literatura sobre los modelos de simulación disponibles en fresado de HT. Se encontraron estudios sobre modelos cadavéricos, basados en impresión 3D, realidad virtual y de bajo costo. Los modelos de impresión 3D y realidad virtual han sido evaluados favorablemente en cuanto a adquisición de habilidades, aprendizaje de anatomía, similitud con modelos cadavéricos y sensación táctil. Los modelos de impresión 3D presentan mayor fidelidad anatómica y física, pero tienen un mayor costo. En suma, se han desarrollado modelos de fresado de HT no cadavéricos que cuentan, principalmente, con validez de apariencia y contenido, y solo algunos con validez de constructo. Se necesitan más estudios para evaluar su validez predictiva y transferencia de habilidades al paciente real.

Temporal bone (TB) dissection is a challenging procedure for otolaryngologists. It requires a detailed knowledge of this anatomically complex area and mastery of the surgical technique. Exposure to a simple or radical mastoidectomy may vary among residents and specialty programs, frequently not complying with the required number of surgeries to complete the learning curve during residency. Hence, TB dissection simulation is of great importance. The gold standard for simulated training are cadaveric models, nevertheless, the associated high cost and low availability represent a major limitation for this modality. Non-cadaveric simulation models could play a key role in simulated training for this surgery. A comprehensive review of the literature regarding the available simulation models for TB dissection was conducted. Articles for cadaveric, 3D-printed, virtual reality and low-cost models were identified. 3D-printed and virtual reality models have been favorably evaluated in terms of skill acquisition, anatomy learning, similarity to cadaveric models, and tactile sensation. 3D-printed models present superior anatomic and physical fidelity, but are more expensive. In sum, the current non-cadaveric models for TB dissection mostly present face and content validity, while few models count with construct validity. Further studies are required to assess predictive validity and skill transfer to the real patient.

Impresión 3D de medicamentos / 3D Printing of medicines

La industria farmacéutica está en continua búsqueda de nuevas tecnologías que permitan mejorar las formas de dosificación de las que se dispone, siendo uno de los objetivos el aumento de la adherencia a los tratamientos por parte de los pacientes. En este sentido, la impresión en 3 dimensiones (3DP) es una emergente técnica de fabricación aditiva que ha comenzado a abarcar muchos sectores industriales e influir directa e indirectamente en la calidad de vida de los individuos. Tanto es así, que la 3DP se postula como una de las técnicas que podría contribuir a que se produzca un gran cambio en el sector farmacéutico, permitiendo la personalización de los tratamientos de los pacientes, mejorando la biodisponibilidad de fármacos que presentan problemas de disolución o combinando toda la medicación de un paciente en una sola forma farmacéutica de toma diaria (polypill), entre otros. Esta nueva técnica de producción va a diferir enormemente de las clásicas formas de fabricación farmacéuticas y, en los próximos años puede suponer una transformación revolucionaria en la práctica farmacéutica. (AU)

The pharmaceutical industry is continually searching for new technologies to improve the characteristics of current medicines. One of the objectives is the increase of adherence to the treatments by patients. Simultaneously, 3-dimensional printing (3DP) is an emerging additive technique that is reaching many sectors of industry and influencing directly and indirectly the quality of life of patients. In this sense, 3DP postulates to be one of the technologies that contribute to the pharmaceutical development, allowing the personalized medicine in patients, improving the bioavailability of drugs with dissolution problems or combining all the medication of the patients in a single tablet (polypill), among others. This new technique will differ greatly from the traditional pharmaceutical manufacturing and in the coming years it may involve a revolutionary transformation in pharmaceutical practice. (AU)

Telemedicina en retinopatía del prematuro: Atravesando fronteras en la salud visual pediátrica. Estudio TELEROP / Telemedicine in retinopathy of prematurity: Crossing borders in pediatric vision health. TELEROP study

Objetivo general Evaluar la precisión y validez de imágenes vía teléfono inteligente en comparación con el sistema RetCam® para el diagnóstico de retinopatía del prematuro (ROP). Metodología Estudio observacional, de corte longitudinal y enmascarado realizado en el hospital Dr. Elías Santana. Se incluyeron infantes con peso al nacer ≤ 1.500 g, edad gestacional ≤ 30 semanas y/o pacientes expuestos a factores de riesgo o complicaciones ligadas a ROP. Estos sujetos fueron tamizados empleando imágenes vía teléfono inteligente o RetCam®, ambos comparados con la fondoscopía convencional. Se utilizó la clasificación de ICROP para la estadificación. Los resultados principales analizados fueron sensibilidad, especificidad, valores predictivos e índice kappa. Resultados Se obtuvieron 915 imágenes (n = 121), distribuidas en grupo teléfono inteligente (50,4%) y grupo RetCam® (49,6%) entre agosto del 2020 y marzo del 2021. Los sujetos que presentaron ROP tuvieron menor edad gestacional (30,2 sem ± 2.8), peso al nacer (1.361 g ± 398) y mayor exposición a oxigenoterapia (12,8 días ± 11,3). El grupo RetCam® presentó sensibilidad = 80%, especificidad = 78%, valor predictivo positivo = 90% e índice kappa = 0,70. El grupo teléfono inteligente presentó sensibilidad = 88%, especificidad = 90%, valor predictivo positivo = 93,75% e índice kappa = 0,81. Conclusiones Ambos métodos diagnósticos fueron precisos para identificar ROP. El grupo teléfono inteligente obtuvo resultados superiores con una excelente resolución, representando un método costo-efectivo para crear un impacto global en la reducción de la ceguera prevenible en población pediátrica (AU)

General objective To evaluate the accuracy and validity of images with smartphone compared to the RetCam® system for the diagnosis of retinopathy of prematurity (ROP). Methodology Observational, longitudinal and masked study carried out at the Dr. Elías Santana hospital. Infants with birth weight ≤ 1500 g, gestational age ≤ 30 weeks and/or patients exposed to risk factors or complications linked to ROP were included. These subjects were screened using images with smartphone or RetCam®, both compared to conventional fundoscopy. The ICROP classification was used for staging. The main results analyzed were sensitivity, specificity, positive predictive values and kappa index. Results 915 images (n = 121) were obtained, distributed in smartphone group (50.4%) and RetCam® group (49.6%) between August 2020 and March 2021. Subjects with ROP had lower gestational age (30.2 sem ± 2.8), birth weight (1361 g ± 398), and greater exposure to oxygen therapy (12.8 days ± 11.3). The RetCam® group presented sensitivity = 80%, specificity = 78%, positive predictive value = 90% and kappa index = 0.70. The smartphone group presented sensitivity = 88%, specificity = 90%, positive predictive value = 93.75% and kappa index = 0.81. Conclusions Both diagnostic methods were accurate to identify ROP. The smartphone group obtained superior results with excellent resolution, representing a cost-effective method to create a global impact on reducing preventable blindness in the pediatric population (AU)

Validación de los modelos de impresión 3D paciente-específicos para cirugía ortopédica oncológica pélvica / Validation of patient-specific 3D impression models for pelvic oncological orthopedic surgery

Introducción: Los tumores del anillo pélvico suponen un reto por la dificultad de obtener márgenes quirúrgicos adecuados. Herramientas como la navegación quirúrgica o la impresión 3D para la fabricación de plantillas de posicionamiento quirúrgico paciente-específicas ayudan en la planificación preoperatoria y la ejecución intraoperatoria. Su correcta colocación es fundamental en localizaciones complejas como la pelvis, por lo que es necesario identificar los errores de posicionamiento. El objetivo de este estudio es demostrar la fiabilidad en la colocación de plantillas 3D para la realización de osteotomías en el anillo pélvico. Material y métodos: Estudio experimental en cadáver con 10 hemipelvis. Se realiza TC para la obtención del modelo tridimensional, planificación de osteotomías, diseño de plantillas de posicionamiento en rama isquiopubiana (I), iliopubiana (P), supracetabular (S) y cresta iliaca (C); y un marcador de posicionamiento (rigid-body) sobre las plantillas C y S para la navegación. Las plantillas y el rigid-body son impresos en 3D y se colocan según planificación previa. La navegación permite comprobar la posición final de las plantillas y de las osteotomías. Resultados: El posicionamiento de las plantillas respecto a la planificación preoperatoria varió dependiendo de la localización, siendo mayor el error en las de cresta iliaca. Utilizando la navegación, la media de error de distancia al plano de corte está en 3,5mm, excepto en pubis (5-8mm), estando condicionado por la posición del rigid body. Conclusión: El uso de plantillas paciente-específicas impresas en 3D es una herramienta fiable para la realización de osteotomías en cirugía oncológica pélvica.(AU)

Introduction: Pelvic ring tumors pose a challenge due to the difficulty in obtaining adequate surgical margins. Tools such as surgical navigation or 3D printing for the fabrication of patient-specific surgical positioning templates help in preoperative planning and intraoperative execution. Their correct positioning is essential in complex locations such as the pelvis, so it is necessary to identify positioning errors. The aim of this study is to demonstrate the reliability of 3D template placement for pelvic ring osteotomies. Material and methods: Experimental study in cadaver with 10 hemipelvis. CT was performed to obtain the three-dimensional model, planning of osteotomies, design of positioning templates in ischiopubic (I), iliopubic (P), supracetabular (S) and iliac crest (C) branches; and a positioning marker (rigid-body) on the C and S templates for navigation. The templates and rigid-body are 3D printed and positioned according to pre-planning. Navigation allows the final position of the inserts and osteotomies to be checked. Results: The positioning of the templates with respect to the preoperative planning varied depending on the location, being greater the error in those of the iliac crest. Using navigation the mean error of distance to the cutting plane is 3.5mm, except in pubis 5-8mm), being conditioned by the position of the rigid body. Conclusion: The use of patient-specific templates printed in 3D is a reliable tool for performing osteotomies in pelvic cancer surgery.(AU)

[Translated article] Validation of patient-specific 3D impression models for pelvic oncological orthopedic surgery / Validación de los modelos de impresión 3D paciente-específicos para cirugía ortopédica oncológica pélvica

Introducción: Los tumores del anillo pélvico suponen un reto por la dificultad de obtener márgenes quirúrgicos adecuados. Herramientas como la navegación quirúrgica o la impresión 3D para la fabricación de plantillas de posicionamiento quirúrgico paciente-específicas ayudan en la planificación preoperatoria y la ejecución intraoperatoria. Su correcta colocación es fundamental en localizaciones complejas como la pelvis, por lo que es necesario identificar los errores de posicionamiento. El objetivo de este estudio es demostrar la fiabilidad en la colocación de plantillas 3D para la realización de osteotomías en el anillo pélvico. Material y métodos: Estudio experimental en cadáver con 10 hemipelvis. Se realiza TC para la obtención del modelo tridimensional, planificación de osteotomías, diseño de plantillas de posicionamiento en rama isquiopubiana (I), iliopubiana (P), supracetabular (S) y cresta iliaca (C); y un marcador de posicionamiento (rigid-body) sobre las plantillas C y S para la navegación. Las plantillas y el rigid-body son impresos en 3D y se colocan según planificación previa. La navegación permite comprobar la posición final de las plantillas y de las osteotomías. Resultados: El posicionamiento de las plantillas respecto a la planificación preoperatoria varió dependiendo de la localización, siendo mayor el error en las de cresta iliaca. Utilizando la navegación, la media de error de distancia al plano de corte está en 3,5mm, excepto en pubis (5-8mm), estando condicionado por la posición del rigid body. Conclusión: El uso de plantillas paciente-específicas impresas en 3D es una herramienta fiable para la realización de osteotomías en cirugía oncológica pélvica.(AU)

Introduction: Pelvic ring tumors pose a challenge due to the difficulty in obtaining adequate surgical margins. Tools such as surgical navigation or 3D printing for the fabrication of patient-specific surgical positioning templates help in preoperative planning and intraoperative execution. Their correct positioning is essential in complex locations such as the pelvis, so it is necessary to identify positioning errors. The aim of this study is to demonstrate the reliability of 3D template placement for pelvic ring osteotomies. Material and methods: Experimental study in cadaver with 10 hemipelvis. CT was performed to obtain the three-dimensional model, planning of osteotomies, design of positioning templates in ischiopubic (I), iliopubic (P), supracetabular (S) and iliac crest (C) branches; and a positioning marker (rigid-body) on the C and S templates for navigation. The templates and rigid-body are 3D printed and positioned according to pre-planning. Navigation allows the final position of the inserts and osteotomies to be checked. Results: The positioning of the templates with respect to the preoperative planning varied depending on the location, being greater the error in those of the iliac crest. Using navigation the mean error of distance to the cutting plane is 3.5mm, except in pubis 5-8mm), being conditioned by the position of the rigid body. Conclusion: The use of patient-specific templates printed in 3D is a reliable tool for performing osteotomies in pelvic cancer surgery.(AU)

Telemedicine in retinopathy of prematurity: Crossing borders in pediatric vision health. TELEROP study.

GENERAL OBJECTIVE: To evaluate the accuracy and validity of images with smartphone compared to the RetCam® system for the diagnosis of retinopathy of prematurity (ROP). METHODOLOGY: Observational, longitudinal and masked study carried out at the Dr. Elías Santana hospital. Infants with birth weight ≤1500 g, gestational age ≤30 weeks and/or patients exposed to risk factors or complications linked to ROP were included. These subjects were screened using images with smartphone or RetCam®, both compared to conventional fundoscopy. The ICROP classification was used for staging. The main results analyzed were sensitivity, specificity, positive predictive values and kappa index. RESULTS: 915 images (n = 121) were obtained, distributed in smartphone group (50.4%) and RetCam® group (49.6%) between August 2020 and March 2021. Subjects with ROP had lower gestational age (30.2 sem ± 2.8), birth weight (1361 g ± 398), and greater exposure to oxygen therapy (12.8 days ± 11.3). The RetCam® group presented sensitivity = 80%, specificity = 78%, positive predictive value = 90% and kappa index = 0.70. The smartphone group presented sensitivity = 88%, specificity = 90%, positive predictive value = 93.75% and kappa index = 0.81. CONCLUSIONS: Both diagnostic methods were accurate to identify ROP. The smartphone group obtained superior results with excellent resolution, representing a cost-effective method to create a global impact on reducing preventable blindness in the pediatric population.

[Translated article] Validation of patient-specific 3D impression models for pelvic oncological orthopedic surgery.

INTRODUCTION: Pelvic ring tumours pose a challenge due to the difficulty in obtaining adequate surgical margins. Tools such as surgical navigation or 3D printing for the fabrication of patient-specific surgical positioning templates help in preoperative planning and intraoperative execution. Their correct positioning is essential in complex locations such as the pelvis, so it is necessary to identify positioning errors. The aim of this study is to demonstrate the reliability of 3D template placement for pelvic ring osteotomies. MATERIAL AND METHODS: Experimental study in cadaver with 10 hemipelvis. CT was performed to obtain the three-dimensional model, planning of osteotomies, design of positioning templates in ischiopubic (I), iliopubic (P), supracetabular (S) and iliac crest (C) branches; and a positioning marker (rigid-body) on the C and S templates for navigation. The templates and rigid-body are 3D printed and positioned according to pre-planning. Navigation allows the final position of the inserts and osteotomies to be checked. RESULTS: The positioning of the templates with respect to the preoperative planning varied depending on the location, being greater the error in those of the iliac crest. Using navigation the mean error of distance to the cutting plane is 3.5mm, except in pubis (5-8mm), being conditioned by the position of the rigid body. CONCLUSION: The use of patient-specific templates printed in 3D is a reliable tool for performing osteotomies in pelvic cancer surgery.

Aplicación de la medicina regenerativa y la bioimpresión 3D en urología / Application of regenerative medicine and 3D bioprinting in urology

In the last two decades, a new purpose has collected great efforts from scientists in all branches of medicine. It is about the possibility to make the body regenerate ill tissues and organs by itself with de right artificial stimuli or the construction of new functional organs to replace the damaged ones. This process comprises various interdisciplinary approaches to healthcare, such as tissue engineering, molecular medicine, biotechnology, and three-dimensional printing. Urologists have been remarkably active in this field of medicine called Regenerative Medicine. The searching of the different requirements like suitable and compatible biomaterials, versatile cells, adequate techniques to construct tissues, available biomolecules, and the knowledge of all these minimizing risks, are some of the aims and the approximations until now. Despite many obstacles, in vitro and in vivo studies are already showing encouraging options. We will review the advances related to the bladder, urethra, ureter, and kidneys. Difficulties such as ethical issues, time investment and high costs, have been some of the drawbacks encountered. Further studies are still required for its clinical application in daily life (AU)

En los últimos 20 años, los esfuerzos de científicos de todas las especialidades médicas se han dirigido hacia un nuevo objetivo. Se trata de la posibilidad de que el cuerpo regenere por sí mismo los tejidos y órganos enfermos con los estímulos artificiales adecuados o la construcción de nuevos órganos funcionales para sustituir los dañados. Este proceso conlleva la colaboración por parte de otras ciencias como la ingeniería de materiales, la medicina molecular, la biotecnología y la impresión tridimensional. En la denominada medicina regenerativa, los urólogos han desempeñado un papel especialmente activo. La búsqueda de los diferentes factores requeridos, como biomateriales adecuados y compatibles, células versátiles, técnicas adecuadas para construir tejidos, biomoléculas disponibles y el conocimiento de todo ello, minimizando los riesgos, son algunos de los objetivos y aproximaciones actuales. A pesar de los obstáculos, hay estudios in vitro e in vivo que ya han revelado opciones esperanzadoras. Repasaremos los avances relacionados con la vejiga, la uretra, el uréter y los riñones. Las dificultades como las cuestiones éticas, la inversión de tiempo y los altos costes, han sido algunos de los inconvenientes encontrados. Todavía se requieren más estudios para su aplicación clínica en la vida diaria (AU)

Application of regenerative medicine and 3d bioprinting in urology.

In the last two decades, a new purpose has collected great efforts from scientists in all branches of medicine. It is about the possibility to make the body regenerate ill tissues and organs by itself with de right artificial stimuli or the construction of new functional organs to replace the damaged ones. This process comprises various interdisciplinary approaches to healthcare, such as tissue engineering, molecular medicine, biotechnology, and three-dimensional printing. Urologists have been remarkably active in this field of medicine called Regenerative Medicine. The searching of the different requirements like suitable and compatible biomaterials, versatile cells, adequate techniques to construct tissues, available biomolecules, and the knowledge of all these minimizing risks, are some of the aims and the approximations until now. Despite many obstacles, in vitro and in vivo studies are already showing encouraging options. We will review the advances related to the bladder, urethra, ureter, and kidneys. Difficulties such as ethical issues, time investment and high costs, have been some of the drawbacks encountered. Further studies are still required for its clinical application in daily life.