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1.
Phys Rev Lett ; 126(11): 114501, 2021 Mar 19.
Artículo en Inglés | MEDLINE | ID: mdl-33798375

RESUMEN

We demonstrate flow rectification, valveless pumping, or alternating to direct current (AC-to-DC) conversion in macroscale fluidic networks with loops. Inspired by the unique anatomy of bird lungs and the phenomenon of directed airflow throughout the respiration cycle, we hypothesize, test, and validate that multiloop networks exhibit persistent circulation or DC flows when subject to oscillatory or AC forcing at high Reynolds numbers. Experiments reveal that disproportionately stronger circulation is generated for higher frequencies and amplitudes of the imposed oscillations, and this nonlinear response is corroborated by numerical simulations. Visualizations show that flow separation and vortex shedding at network junctions serve the valving function of directing current with appropriate timing in the oscillation cycle. These findings suggest strategies for controlling inertial flows through network topology and junction connectivity.


Asunto(s)
Aves/fisiología , Pulmón/fisiología , Modelos Biológicos , Animales , Aves/anatomía & histología , Simulación por Computador , Pulmón/anatomía & histología , Modelos Anatómicos , Respiración
2.
Indian J Ophthalmol ; 69(4): 982-984, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33727472

RESUMEN

The COVID-19 pandemic has resulted in reduction of patient volumes in Ophthalmology. With only emergency surgical procedures being performed with few elective surgical procedures, surgical volumes are at an all-time low. This has resulted in decreased surgical training opportunities for trainee surgeons. We developed a simple, cost-effective, 3D printed model eye - RetiSurge - for "Dry Lab" vitreoretinal surgery training. The model incorporates a retinal film that can be changed, making it suitable for multiple uses. The RetiSurge model can be used to practice visualization, instrument manipulation and endolaser photocoagulation. RetiSurge can be sterilized by ethylene oxide and is safe for use inside the operating room. RetiSurge is a simple, cost-effective, and reusable model eye for early training in Vitreoretinal surgery.


Asunto(s)
/epidemiología , Educación de Postgrado en Medicina/métodos , Modelos Anatómicos , Oftalmología/educación , Cirugía Vitreorretiniana/educación , Competencia Clínica , Humanos , Imagenología Tridimensional , India/epidemiología , Internado y Residencia
3.
J Vis Exp ; (168)2021 02 25.
Artículo en Inglés | MEDLINE | ID: mdl-33720143

RESUMEN

Therapies based upon whole-body biomechanical assessments are successful for injury prevention and rehabilitation in human athletes. Similar approaches have rarely been used to study equine athletic injury. Degenerative osteoarthritis caused by mechanical stress can originate from chronic postural dysfunction, which, because the primary dysfunction is often distant from the site of tissue injury, is best identified through modeling whole-body biomechanics. To characterize whole-body equine kinematics, a realistic skeletal model of a horse was created from equine computed tomography (CT) data that can be used for functional anatomical and biomechanical modeling. Equine CT data were reconstructed into individual three-dimensional (3D) data sets (i.e., bones) using 3D visualization software and assembled into a complete 3D skeletal model. The model was then rigged and animated using 3D animation and modeling software. The resulting 3D skeletal model can be used to characterize equine postures associated with degenerative tissue changes as well as to identify postures that reduce mechanical stress at the sites of tissue injury. In addition, when animated into 4D, the model can be used to demonstrate unhealthy and healthy skeletal movements and can be used to develop preventative and rehabilitative individualized therapies for horses with degenerative lamenesses. Although the model will soon be available for download, it is currently in a format that requires access to the 3D animation and modeling software, which has quite a learning curve for new users. This protocol will guide users in (1) developing such a model for any organism of interest and (2) using this specific equine model for their own research questions.


Asunto(s)
Caballos/anatomía & histología , Imagenología Tridimensional , Modelos Anatómicos , Esqueleto/anatomía & histología , Tomografía Computarizada por Rayos X , Animales , Fenómenos Biomecánicos , Miembro Anterior/anatomía & histología , Miembro Posterior/anatomía & histología , Programas Informáticos
4.
Clin Otolaryngol ; 46(3): 614-618, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33533176

RESUMEN

OBJECTIVES: The aim of this study was to examine contamination from otolaryngologic procedures involving high-speed drilling, specifically mastoid surgery, and to assess the adequacy of PPE in such procedures. DESIGN AND SETTING: Mastoid surgery was simulated in a dry laboratory using a plastic temporal bone, microscope and handheld drill with irrigation and suction. Comparisons of distance of droplet and bone dust contamination and surgeon contamination were made under differing conditions. Irrigation speed, use of microscope and drill burr size and type were compared. MAIN OUTCOME MEASURES: Measurement of the distance of field contamination while performing simulated mastoidectomy and location of surgeon contamination. RESULTS: There was a greater distance field contamination and surgeon contamination without the use of the microscope. Contamination was reduced by using a smaller drill burr and by using a diamond burr when compared to a cutting burr. The use of goggles and a face mask provided good protection for the surgeon. However, the microscope alone may provide sufficient protection to negate the need for goggles. CONCLUSIONS: While the risks of performing mastoid surgery during the coronavirus pandemic cannot be completely removed, they can be mitigated. Such factors include using the microscope for all drilling, using smaller size drill burrs and creating a safe zone around the operating table.


Asunto(s)
/prevención & control , Control de Infecciones , Transmisión de Enfermedad Infecciosa de Paciente a Profesional/prevención & control , Mastoidectomía , Equipo de Protección Personal , Polvo , Humanos , Modelos Anatómicos , Succión , Irrigación Terapéutica
5.
JAMA Netw Open ; 4(2): e2037519, 2021 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-33599774

RESUMEN

Importance: In acetabular fracture surgery, achieving an optimal reconstruction of the articular surface decreases the risk of osteoarthritis and the subsequent need for total hip arthroplasty. However, no one-size-fits-all osteosynthesis plate is available owing to differences in fracture patterns and variations in pelvic anatomy. Currently, osteosynthesis plates need to be manually contoured intraoperatively, often resulting in inadequate reduction and fixation of the fractured segments. Objective: To determine the feasibility and accuracy of a novel concept of fast-track 3-dimensional (3-D) virtual surgical planning and patient-specific osteosynthesis for complex acetabular fracture surgery. Design, Setting, and Participants: This case series study examines the use of patient-specific osteosynthesis plates for patients needing operative treatment for displaced associated-type acetabular fractures at a tertiary university-affiliated referral center and level 1 trauma center between January 1, 2017, and December 31, 2018. Models were created in 3-D based on computed tomography (CT) data, fractures were virtually reduced, and implant positions were discussed in a multidisciplinary team of clinicians and engineers. Patient-specific osteosynthesis plates with drilling guides were designed, produced, sterilized and clinically applied within 4 days. Data were analyzed at the 1-year follow-up. Exposures: Development and clinical implementation of personalized fracture surgery. Main Outcomes and Measures: The primary outcome was the quality of the reduction as determined by the postoperative CT scan. The secondary outcomes were accuracy of the screw placement and clinical outcome using patient-reported outcome measures. Results: Ten patients with a median (range) age of 63 (46-79) years with an acetabular fracture were included. The median (interquartile range [IQR]) preoperative gap was 20 (15-22) mm, and the median (IQR) step-off was 5 (3-11) mm. Postoperatively, the median (IQR) gap was reduced to 3 (2-5) mm (P = .005), and the median (IQR) step-off was reduced to 0 (0-2) mm (P = .01), indicating good fracture reduction, indicating good fracture reduction. The mean difference between the preoperative and postoperative gap was 14.6 (95% CI, 10-19) mm, and the mean difference in step-off was 5.7 (95% CI, 2-9) mm. The median (IQR) difference in screw direction between the planning and actual surgery was only 7.1° (7°-8°). All patients retained their native hip and reported good physical functioning at follow-up. Conclusions and Relevance: These findings suggest that 3-D virtual surgical planning, manufacturing, and clinical application of patient-specific osteosynthesis plates and drilling guides was feasible and yielded good clinical outcomes. Fast-track personalized surgical treatment could open a new era for the treatment of complex injuries.


Asunto(s)
Acetábulo/lesiones , Placas Óseas , Fijación Interna de Fracturas/instrumentación , Fijación Interna de Fracturas/métodos , Fracturas Óseas/cirugía , Acetábulo/diagnóstico por imagen , Anciano , Estudios de Factibilidad , Femenino , Fracturas Óseas/diagnóstico por imagen , Humanos , Imagenología Tridimensional , Masculino , Industria Manufacturera , Persona de Mediana Edad , Modelos Anatómicos , Medición de Resultados Informados por el Paciente , Impresión Tridimensional , Tomografía Computarizada por Rayos X , Resultado del Tratamiento
7.
Bone Joint J ; 103-B(2): 294-298, 2021 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-33517721

RESUMEN

AIMS: The aim of this study was to determine the immediate post-fixation stability of a distal tibial fracture fixed with an intramedullary nail using a biomechanical model. This was used as a surrogate for immediate weight-bearing postoperatively. The goal was to help inform postoperative protocols. METHODS: A biomechanical model of distal metaphyseal tibial fractures was created using a fourth-generation composite bone model. Three fracture patterns were tested: spiral, oblique, and multifragmented. Each fracture extended to within 4 cm to 5 cm of the plafond. The models were nearly-anatomically reduced and stabilized with an intramedullary nail and three distal locking screws. Cyclic loading was performed to simulate normal gait. Loading was completed in compression at 3,000 N at 1 Hz for a total of 70,000 cycles. Displacement (shortening, coronal and sagittal angulation) was measured at regular intervals. RESULTS: The spiral and oblique fracture patterns withstood simulated weight-bearing with minimal displacement. The multifragmented model had early implant failure with breaking of the distal locking screws. The spiral fracture model shortened by a mean of 0.3 mm (SD 0.2), and developed a mean coronal angulation of 2.0° (SD 1.9°) and a mean sagittal angulation of 1.2° (SD 1.1°). On average, 88% of the shortening, 74% of the change in coronal alignment, and 75% of the change in sagittal alignment occurred in the first 2,500 cycles. No late acceleration of displacement was noted. The oblique fracture model shortened by a mean of 0.2 mm (SD 0.1) and developed a mean coronal angulation of 2.4° (SD 1.6°) and a mean sagittal angulation of 2.6° (SD 1.4°). On average, 44% of the shortening, 39% of the change in coronal alignment, and 79% of the change in sagittal alignment occurred in the first 2,500 cycles. No late acceleration of displacement was noted. CONCLUSION: For spiral and oblique fracture patterns, simulated weight-bearing resulted in a clinically acceptable degree of displacement. Most displacement occurred early in the test period, and the rate of displacement decreased over time. Based on this model, we offer evidence that early weight-bearing appears safe for well reduced oblique and spiral fractures, but not in multifragmented patterns that have poor bone contact. Cite this article: Bone Joint J 2021;103-B(2):294-298.


Asunto(s)
Ambulación Precoz , Fijación Intramedular de Fracturas/métodos , Cuidados Posoperatorios/métodos , Fracturas de la Tibia/cirugía , Fenómenos Biomecánicos , Clavos Ortopédicos , Tornillos Óseos , Fijación Intramedular de Fracturas/instrumentación , Fijación Intramedular de Fracturas/rehabilitación , Humanos , Modelos Anatómicos , Tibia/lesiones , Tibia/fisiología , Tibia/cirugía , Fracturas de la Tibia/rehabilitación , Soporte de Peso
8.
Sensors (Basel) ; 21(4)2021 Feb 09.
Artículo en Inglés | MEDLINE | ID: mdl-33572091

RESUMEN

Even though animal trials are a controversial topic, they provide knowledge about diseases and the course of infections in a medical context. To refine the detection of abnormalities that can cause pain and stress to the animal as early as possible, new processes must be developed. Due to its noninvasive nature, thermal imaging is increasingly used for severity assessment in animal-based research. Within a multimodal approach, thermal images combined with anatomical information could be used to simulate the inner temperature profile, thereby allowing the detection of deep-seated infections. This paper presents the generation of anatomical thermal 3D models, forming the underlying multimodal model in this simulation. These models combine anatomical 3D information based on computed tomography (CT) data with a registered thermal shell measured with infrared thermography. The process of generating these models consists of data acquisition (both thermal images and CT), camera calibration, image processing methods, and structure from motion (SfM), among others. Anatomical thermal 3D models were successfully generated using three anesthetized mice. Due to the image processing improvement, the process was also realized for areas with few features, which increases the transferability of the process. The result of this multimodal registration in 3D space can be viewed and analyzed within a visualization tool. Individual CT slices can be analyzed axially, sagittally, and coronally with the corresponding superficial skin temperature distribution. This is an important and successfully implemented milestone on the way to simulating the internal temperature profile. Using this temperature profile, deep-seated infections and inflammation can be detected in order to reduce animal suffering.


Asunto(s)
Procesamiento de Imagen Asistido por Computador , Imagenología Tridimensional , Tomografía Computarizada por Rayos X , Animales , Ratones , Modelos Anatómicos , Movimiento (Física)
9.
Br J Oral Maxillofac Surg ; 59(4): 466-471, 2021 05.
Artículo en Inglés | MEDLINE | ID: mdl-33468331

RESUMEN

Sagittal split ramus osteotomy (SSRO) with large mandibular advancements is a common surgical procedure and could be indicated for patients with sleep apnoea. As a large variety of fixation methods is used for the stabilisation of SSRO, a biomechanical test model was used to analyse which fixation technique was most stable. For this in vitro study, 80 polyurethane hemimandibles with a prefabricated SSRO were used as substrates. Loads in Newtons were recorded at displacements of the mandibular incisive edge at 1mm, 3mm and 5mm. The samples were divided into two groups: mandibular advancements of 10mm and 15mm. In both groups, four fixation techniques were used: (A) one four-hole miniplate; (B) two four-hole miniplates; (C) one four-hole miniplate plus one bicortical screw; and (D) three bicortical screws in an inverted-L arrangement. In group 1, three bicortical screws resulted in the best stability, and in group 2, two miniplates resulted in the best stability. The use of two miniplates did not show significant differences between both groups. Other fixation methods showed more stability with 10mm advancements. This study therefore suggests that in SSRO with advancements exceeding 10mm, the use of two miniplates is the optimal means of providing rigid fixation.


Asunto(s)
Avance Mandibular , Osteotomía Sagital de Rama Mandibular , Fenómenos Biomecánicos , Placas Óseas , Humanos , Mandíbula/cirugía , Modelos Anatómicos
11.
Neuroimage ; 228: 117696, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33385544

RESUMEN

BACKGROUND: During transcranial magnetic stimulation (TMS) a coil placed on the scalp is used to non-invasively modulate activity of targeted brain networks via a magnetically induced electric field (E-field). Ideally, the E-field induced during TMS is concentrated on a targeted cortical region of interest (ROI). Determination of the coil position and orientation that best achieve this objective presently requires a large computational effort. OBJECTIVE: To improve the accuracy of TMS we have developed a fast computational auxiliary dipole method (ADM) for determining the optimum coil position and orientation. The optimum coil placement maximizes the E-field along a predetermined direction or, alternatively, the overall E-field magnitude in the targeted ROI. Furthermore, ADM can assess E-field uncertainty resulting from precision limitations of TMS coil placement protocols. METHOD: ADM leverages the electromagnetic reciprocity principle to compute rapidly the TMS induced E-field in the ROI by using the E-field generated by a virtual constant current source residing in the ROI. The framework starts by solving for the conduction currents resulting from this ROI current source. Then, it rapidly determines the average E-field induced in the ROI for each coil position by using the conduction currents and a fast-multipole method. To further speed-up the computations, the coil is approximated using auxiliary dipoles enabling it to represent all coil orientations for a given coil position with less than 600 dipoles. RESULTS: Using ADM, the E-fields generated in an MRI-derived head model when the coil is placed at 5900 different scalp positions and 360 coil orientations per position (over 2.1 million unique configurations) can be determined in under 15 min on a standard laptop computer. This enables rapid extraction of the optimum coil position and orientation as well as the E-field variation resulting from coil positioning uncertainty. ADM is implemented in SimNIBS 3.2. CONCLUSION: ADM enables the rapid determination of coil placement that maximizes E-field delivery to a specific brain target. This method can find the optimum coil placement in under 15 min enabling its routine use for TMS. Furthermore, it enables the fast quantification of uncertainty in the induced E-field due to limited precision of TMS coil placement protocols, enabling minimization and statistical analysis of the E-field dose variability.


Asunto(s)
Simulación por Computador , Estimulación Magnética Transcraneal/métodos , Campos Electromagnéticos , Humanos , Modelos Anatómicos
12.
Medicine (Baltimore) ; 100(2): e24099, 2021 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-33466177

RESUMEN

BACKGROUND: To explore the ideal trajectory of lumbar cortical bone trajectory screws and provide the optimal placement scheme in clinical applications. METHODS: Lumbar computed tomography (CT) data of 40 patients in our hospital were selected, and the cortical vertebral bone contour model was reconstructed in three dimensions (3D). Depending on the different regions of the screw through the entrance and exit of the pedicle, 9 trajectories were obtained through combinational design: T-Aa, T-Ab, T-Ac, T-Ba, T-Bb, T-Bc, T-Ca, T-Cb, and T-Cc. Cortical bone trajectory (CBT) screws with appropriate diameters were selected to simulate screw placement and measure the parameters corresponding to each trajectory (screw path diameter, screw trajectory length, cephalad angle, and lateral angle), and then determine the optimal screw according to the screw parameters and screw safety. Then, 23 patients in our hospital were selected, and the navigation template was designed based on the ideal trajectory before operation, CBT screws were placed during the operation to further verify the safety and feasibility of the ideal trajectory. RESULTS: T-Bc and T-Bb are the ideal screw trajectories for L1-L2 and L3-L5, respectively. The screw placement point is located at the intersection of the inner 1/3 vertical line of the superior facet joint and the bottom 1/3 horizontal line of the outer crest of the vertebral lamina (i.e., 2-4 mm inward at the bottom 1/3 of the outer crest of the vertebral lamina). CBT screws were successfully placed based on the ideal screw trajectory in clinical practice. During the operation or the follow-up period, there were no adverse events. CONCLUSION: CBT screw placement based on the ideal screw trajectory is a safe and reliable method for achieving effective fixation and satisfactory postoperative effects.


Asunto(s)
Hueso Cortical/lesiones , Fijación de Fractura/instrumentación , Vértebras Lumbares/lesiones , Tornillos Pediculares , Fracturas de la Columna Vertebral/cirugía , Simulación por Computador , Hueso Cortical/diagnóstico por imagen , Hueso Cortical/cirugía , Humanos , Vértebras Lumbares/diagnóstico por imagen , Vértebras Lumbares/cirugía , Modelos Anatómicos , Fracturas de la Columna Vertebral/diagnóstico por imagen , Tomografía Computarizada por Rayos X , Articulación Cigapofisaria/diagnóstico por imagen , Articulación Cigapofisaria/cirugía
13.
Clin Anat ; 34(3): 496-503, 2021 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-33502787

RESUMEN

The COVID-19 pandemic and mandatory social distancing has brought challenges to anatomy educators who generally need in-person classes. The purpose of this study is to share the experience of a distant online lecture on a surgical procedure and related anatomy in a three-dimensional (3D) virtual reality (VR) workspace and to compare it with reported teaching methods, that is, an in-person class and a Zoom online class. The lecture was delivered by three authors of this article in a VR workspace that enables people to meet through VR. The lectures were about combinations of dental surgical procedures and related clinical anatomy. Physically, the attendees could have been located anywhere in the world, so lecturers joined from the United States and the attendees were all from Japan. VR environment and its flexibility enabled attendees to join the lecture actively, helping them to gain understanding of the surgical procedure and anatomy more efficiently. The use of VR technology with a live communication tool demonstrated in this study has several advantages over previous education methods, although there are still technical issues or disadvantages that need to be addressed. Development of the technology and app/software is required so that more data can be processed at higher speed. Use of VR technology with a live communication tool could be an alternative teaching method. Its overall advantages are a closer look at the slides/monitor and concurrent observation of the multiple assets in various directions by multiple attendees. These advantages cannot be achieved by any other teaching method without VR assets with the workspace provided by Spatial. Even during the mandatory social distancing due to the COVID-19 pandemic, this could enable us to foster 3D understanding of surgery and related anatomy. Further study is now needed to evaluate the effectiveness of this newly proposed teaching method by comparing it with traditional in-person and online classes with a live communication tool.


Asunto(s)
/prevención & control , Educación a Distancia , Modelos Anatómicos , Procedimientos Quirúrgicos Operativos/educación , Realidad Virtual , /epidemiología , Humanos
15.
Br J Oral Maxillofac Surg ; 59(2): e65-e71, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-33358011

RESUMEN

Head and neck cancer patients present unique airway challenges, and oropharyngeal, laryngeal, and hypopharyngeal tumours considerably distort and narrow the anatomy of the airway. We describe the use of 3D augmented reality software combined with 3D printed models to assess the anatomy of difficult airways and to assist in the formulation of the most optimal airway management strategy in such patients. The reported patients had computed tomograms (CT) of the neck prior to their anaesthetic and surgical management. DICOM files of the respective scans were imported to 3D rendering software (OsiriX, Pixmeo). We constructed volume rendered models for initial assessment of the airway then generated serial surface rendered models to create a virtual endoscopic path of the airway to simulate the fibreoptic approach. To further facilitate the study of difficult airways we have subsequently printed 3D models of those that were most difficult using rapid prototyping. Head and neck tumours significantly distort the airway. Thorough study of the relevant anatomy prior to airway management for operating reasons enhances communication between the surgeon and anaesthetist, and aids selection of the most appropriate intubation approach. In conclusion, this paper highlights a useful and novel pre-assessment strategy that allows a virtual, visual, 3-dimensional assessment of the airway anatomy combined with 3D modelling and 3D printing. This enables the airway specialist, anaesthetist, and head and neck surgeon to anticipate any critical steps and adjust the plan accordingly.


Asunto(s)
Modelos Anatómicos , Impresión Tridimensional , Endoscopía , Humanos , Imagenología Tridimensional , Cuello , Programas Informáticos
16.
Plast Reconstr Surg ; 147(1): 162-166, 2021 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-33370061

RESUMEN

BACKGROUND: Orbital blowout fracture reconstruction often requires an implant, which must be shaped at the time of surgical intervention. This process is time-consuming and requires multiple placement trials, possibly risking complications. Three-dimensional printing technology has enabled health care facilities to generate custom anatomical models to which implants can be molded to precisely match orbital anatomy. The authors present their early experience with these models and their use in optimizing orbital fracture fixation. METHODS: Maxillofacial computed tomographic scans from patients with orbital floor or wall fractures were prospectively obtained and digitally reconstructed. Both injured-side and mirrored unaffected-side models were produced in-house by stereolithography printing technique. Models were used as templates for molding titanium reconstruction plates, and plates were implanted to reconstruct the patients' orbital walls. RESULTS: Nine patients (mean age, 15.5 years) were included. Enophthalmos was present in seven patients preoperatively and resolved in six patients with surgery. All patients had excellent conformation of the implant to the fracture site on postoperative computed tomographic scan. Postoperative fracture-side orbital volumes were significantly less than preoperative, and not significantly different from unfractured-side orbital volumes. Total model preparation time was approximately 10 hours. Materials cost was at most $21. Plate bending time was approximately 60 seconds. CONCLUSIONS: Patient-specific orbital models can speed the shaping of orbital reconstruction implants and potentially improve surgical correction of orbital fractures. Production of these models with consumer-grade technology confers the same advantages as commercial production at a fraction of the cost and time. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.


Asunto(s)
Modelos Anatómicos , Fracturas Orbitales/cirugía , Planificación de Atención al Paciente , Impresión Tridimensional/economía , Procedimientos Quirúrgicos Reconstructivos/instrumentación , Adolescente , Niño , Femenino , Estudios de Seguimiento , Humanos , Imagenología Tridimensional/economía , Masculino , Órbita/anatomía & histología , Órbita/diagnóstico por imagen , Órbita/lesiones , Órbita/cirugía , Diseño de Prótesis/economía , Diseño de Prótesis/métodos , Tomografía Computarizada por Rayos X/economía , Resultado del Tratamiento
17.
Methods Mol Biol ; 2221: 223-260, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-32979207

RESUMEN

The surgical model of destabilization of the medial meniscus (DMM) has become a gold standard for studying the onset and progression of post-traumatic osteoarthritis (OA). The DMM model mimics clinical meniscal injury, a known predisposing factor for the development of human OA, and permits the study of structural and biological changes over the course of the disease. In addition, when applied to genetically modified or engineered mouse models, this surgical procedure permits dissection of the relative contribution of a given gene to OA initiation and/or progression. This chapter describes the requirements for the surgical induction of OA in mouse models, and provides guidelines and tools for the subsequent histological, immunohistochemical, and molecular analyses. Methods for the assessment of the contributions of selected genes in genetically modified strains are also provided.


Asunto(s)
Modelos Animales de Enfermedad , Meniscos Tibiales/patología , Modelos Anatómicos , Osteoartritis de la Rodilla , Lesiones de Menisco Tibial , Animales , Progresión de la Enfermedad , Masculino , Ratones , Ratones Transgénicos , Osteoartritis de la Rodilla/genética , Osteoartritis de la Rodilla/patología , Lesiones de Menisco Tibial/genética , Lesiones de Menisco Tibial/cirugía
18.
Neuroimage ; 227: 117682, 2021 02 15.
Artículo en Inglés | MEDLINE | ID: mdl-33359339

RESUMEN

Electroencephalographic (EEG) source reconstruction is a powerful approach that allows anatomical localization of electrophysiological brain activity. Algorithms used to estimate cortical sources require an anatomical model of the head and the brain, generally reconstructed using magnetic resonance imaging (MRI). When such scans are unavailable, a population average can be used for adults, but no average surface template is available for cortical source imaging in infants. To address this issue, we introduce a new series of 13 anatomical models for subjects between zero and 24 months of age. These templates are built from MRI averages and boundary element method (BEM) segmentation of head tissues available as part of the Neurodevelopmental MRI Database. Surfaces separating the pia mater, the gray matter, and the white matter were estimated using the Infant FreeSurfer pipeline. The surface of the skin as well as the outer and inner skull surfaces were extracted using a cube marching algorithm followed by Laplacian smoothing and mesh decimation. We post-processed these meshes to correct topological errors and ensure watertight meshes. Source reconstruction with these templates is demonstrated and validated using 100 high-density EEG recordings from 7-month-old infants. Hopefully, these templates will support future studies on EEG-based neuroimaging and functional connectivity in healthy infants as well as in clinical pediatric populations.


Asunto(s)
Mapeo Encefálico/métodos , Encéfalo , Electroencefalografía , Modelos Anatómicos , Procesamiento de Señales Asistido por Computador , Simulación por Computador , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Programas Informáticos
19.
Respir Physiol Neurobiol ; 285: 103611, 2021 03.
Artículo en Inglés | MEDLINE | ID: mdl-33359758

RESUMEN

Exacerbation of COVID-19 pandemic may lead to acute shortage of ventilators, which may require shared use of ventilator as a lifesaving concept. Two model lungs were ventilated with one ventilator to i) test the adequacy of individual tidal volumes via capnography, ii) assess cross-breathing between lungs, and iii) offer a simulation-based algorithm for ensuring equal tidal volumes. Ventilation asymmetry was induced by placing rubber band around one model lung, and the uneven distribution of tidal volumes (VT) was counterbalanced by elevating airflow resistance (HR) contralaterally. VT, end-tidal CO2 concentration (ETCO2), and peak inspiratory pressure (Ppi) were measured. Unilateral LC reduced VT and elevated ETCO2 on the affected side. Under HR, VT and ETCO2 were re-equilibrated. In conclusion, capnography serves as simple, bedside method for controlling the adequacy of split ventilation in each patient. No collateral gas flow was observed between the two lungs with different time constants. Ventilator sharing may play a role in emergency situations.


Asunto(s)
/terapia , Capnografía/normas , Pulmón/fisiopatología , Modelos Biológicos , Respiración Artificial/instrumentación , Respiración Artificial/normas , /diagnóstico , Simulación por Computador , Servicios Médicos de Urgencia , Humanos , Modelos Anatómicos , Pruebas en el Punto de Atención/normas , Pruebas de Función Respiratoria
20.
Methods Mol Biol ; 2147: 3-18, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-32840806

RESUMEN

The design of optimized scaffolds for tissue engineering and regenerative medicine is a key topic of current research, as the complex macro- and micro-architectures required for scaffold applications depend not only on the mechanical properties but also on the physical and molecular queues of the surrounding tissue within the defect site. Thus, the prediction of optimal features for tissue engineering scaffolds is very important, for both its physical and biological properties.The relationship between high scaffold porosity and high mechanical properties is contradictory, as it becomes even more complex due to the scaffold degradation process. Biomimetic design has been considered as a viable method to design optimum scaffolds for tissue engineering applications. In this research work, the scaffold designs are based on biomimetic boundary-based bone micro-CT data. Based on the biomimetic boundaries and with the aid of topological optimization schemes, the boundary data and given porosity is used to obtain the initial scaffold designs. In summary, the proposed scaffold design scheme uses the principles of both the boundaries and porosity of the micro-CT data with the aid of numerical optimization and simulation tools.


Asunto(s)
Materiales Biomiméticos/síntesis química , Diseño Asistido por Computadora , Diseño de Equipo/métodos , Ingeniería de Tejidos/instrumentación , Andamios del Tejido , Materiales Biomiméticos/química , Biomimética/métodos , Huesos/fisiología , Simulación por Computador , Humanos , Modelos Anatómicos , Porosidad , Medicina Regenerativa/instrumentación , Medicina Regenerativa/métodos , Resistencia al Corte , Resistencia a la Tracción , Ingeniería de Tejidos/métodos , Andamios del Tejido/química , Microtomografía por Rayos X
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