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BACKGROUND: Ventilation monitoring during sleep is performed by sleep test instrumentation that is uncomfortable for the patients due to the presence of the flowmeter. The objective of this study was to evaluate if an innovative type 3 wearable system, the X10X and X10Y, is able to correctly detect events of apnea and hypopnea and to classify the severity of sleep apnea without the use of a flowmeter. METHODS: 40 patients with sleep disordered breathing were analyzed by continuous and simultaneous recording of X10X and X10Y and another certified type 3 system, SOMNOtouch, used for comparison. Evaluation was performed in terms of quality of respiratory signals (scores from 1, lowest, to 5, highest), duration and classification of apneas, as well as identification and duration of hypopneas. RESULTS: 580 periods were evaluated. Mean quality assigned score was 3.37±1.42 and 3.25±1.35 for X10X and X10Y and SOMNOtouch, respectively. The agreement between the two systems was evaluated with grades 4 and 5 in 383 out of 580 cases. A high correlation (r2 = 0.921; p<0.001) was found between the AHI indexes obtained from the two systems. X10X and X10Y devices were able to correctly classify 72.3% of the obstructive apneas, 81% of the central apneas, 61.3% of the hypopneas, and 64.6% of the mixed apneas when compared to SOMNOtouch device. CONCLUSION: The X10X and X10Y devices are able to provide a correct grading of sleep respiratory disorders without the need of a nasal cannula for respiratory flow measurement and can be considered as a type 3 sleep test device for screening tests.
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Flujómetros , Sueño , Dispositivos Electrónicos Vestibles , Adulto , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
To analyze the role of stoma diversion and timing of stoma maintenance in the healing of post-surgical Recto Vaginal Fistulae (psRVF). A retrospective analysis of a prospectively maintained registry. All patients with a psRVF diagnosed at IRCCS Sacro Cuore-Don Calabria Hospital of Negrar di Valpolicella from January 2002 to December 2016 were analyzed. The baseline treatment was a fecal diversion. Patients were divided into two groups according to healing time: < 6 months (Group 1) or > 6 months (Group 2). 2043 women underwent rectal resections in the study period. We recorded 37 patients with psRVF (1.8%). Nineteen women (51.3%) healed (Group 1) within 6 months. The median time of psRVF recovery in group 1 was 99.7 days. Concomitant local treatment of the fistula did not influence the healing rate (p 0.8). Colostomies were significantly higher in group 1 (p 0.003). The size of the psRVF influenced the success rate of fistula healing with loop stoma (p 0.07). A multivariate analysis the presence of fever and pelvic abscess (pelvis sepsis) were significantly associated with diversion failure (p 0.035). A step-up approach with the maintenance of loop stoma at least for six months for all patients with psRVF could be changed. Patients with larger fistula and pelvic sepsis at index procedure should be addressed earlier to a specific second-level treatment.
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Neoplasias Colorrectales/cirugía , Cirugía Colorrectal/métodos , Colostomía/métodos , Endometriosis/cirugía , Complicaciones Posoperatorias/cirugía , Fístula Rectovaginal/cirugía , Recto/cirugía , Estomas Quirúrgicos , Adulto , Anciano , Femenino , Humanos , Persona de Mediana Edad , Complicaciones Posoperatorias/etiología , Fístula Rectovaginal/etiología , Estudios Retrospectivos , Resultado del TratamientoRESUMEN
BACKGROUND: Recent advances in wearable technology make continuous cardiorespiratory monitoring possible, with potential applications in assessment of cardiopulmonary patients, healthy subjects and athletes. The aim of the present study was to qualitatively and quantitatively evaluate a new wearable device (Learn Inspire Free Entertainâ¯=â¯L.I.F.E.) by embedding in a compression shirt a 12lead ECG system and 5 respiratory sensors. METHODS: Thirty cardiorespiratory patients and ten healthy subjects were studied for 24â¯h during their usual life activities. In 8 healthy subjects, simultaneous measurements of the device and of an ergo-spirometer were performed during different levels of ventilation in five different body positions. The quality of ECG signals in terms of measurability of heart rate, P wave, QRS complex and ST segment, was analyzed by four expert cardiologists/respiratory physiologists using an arbitrary 1-5 scale. The sum of the respiratory signals was used to calculate the respiratory rate, inspiratory time and relative changes of tidal volume. These parameters were compared to ergo-spirometer measurements. RESULTS: Median quality value was >3 for heart rate, QRS complex, ST segment and P wave (except in L3, aVL, aVF, V1 and V2 leads). Median quality of respiratory traces was >4 in patients and between 3 and 4 in healthy subjects. The respiratory monitoring of respiratory rate and inspiratory time was accurate in all body positions. Tidal volumes were underestimated due to a high level of ventilation. CONCLUSIONS: The L.I.F.E. device provides an accurate continuous monitoring of cardiorespiratory signals during the 24â¯h both in normal subjects and cardiorespiratory patients.
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Vestuario/normas , Electrocardiografía Ambulatoria/normas , Frecuencia Cardíaca/fisiología , Mecánica Respiratoria/fisiología , Dispositivos Electrónicos Vestibles/normas , Anciano , Anciano de 80 o más Años , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
ABSTRACT: The most significant otologic symptoms, consisting of ear pain, tinnitus, dizziness, hearing loss and auricolar "fullness", generally arise within the auditory system, often are associated with extra auricolar disorders, particularly disorder of the temporo-mandibular joint. In our study we examined a sample of 200 consecutive patients who had experienced severe disabling symptom. The patiens came to maxillofacial specialist assessment for temporomandibular disorder. Each patient was assessed by a detailed anamnestic and clinical temporomandibular joint examination and they are divided into five main groups according classification criteria established by Wilkes; tinnitus and subjective indicators of pain are evaluated. The results of this study provide a close correlation between the joint pathology and otologic symptoms, particularly regarding tinnitus and balance disorders, and that this relationship is greater the more advanced is the stage of joint pathology. Moreover, this study shows that TMD-related tinnitus principally affects a younger population (average fifth decade of life) and mainly women (more than 2/3 of the cases). Such evidence suggests the existence of a specific tinnitus subtype that may be defined as "TMD-related somatosensory tinnitus".
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Trastornos de la Articulación Temporomandibular/complicaciones , Acúfeno/etiología , Factores de Edad , Dolor de Oído/diagnóstico , Dolor de Oído/etiología , Femenino , Humanos , Masculino , Persona de Mediana Edad , Factores Sexuales , Trastornos de la Articulación Temporomandibular/clasificación , Acúfeno/diagnóstico , Vértigo/etiologíaRESUMEN
Recent military combat has heightened awareness to the complexity of blast-related traumatic brain injuries (bTBI). Experiments using animal, cadaver, or biofidelic physical models remain the primary measures to investigate injury biomechanics as well as validate computational simulations, medical diagnostics and therapies, or protection technologies. However, blast injury research has seen a range of irregular and inconsistent experimental methods for simulating blast insults generating results which may be misleading, cannot be cross-correlated between laboratories, or referenced to any standard for exposure. Both the US Army Medical Research and Materiel Command and the National Institutes of Health have noted that there is a lack of standardized preclinical models of TBI. It is recommended that the blast injury research community converge on a consistent set of experimental procedures and reporting of blast test conditions. This chapter describes the blast conditions which can be recreated within a laboratory setting and methodology for testing in vivo models within the appropriate environment.
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Traumatismos por Explosión/patología , Modelos Animales de Enfermedad , Traumatismos del Sistema Nervioso/etiología , Traumatismos del Sistema Nervioso/patología , Animales , Humanos , Masculino , RatasRESUMEN
Schwannoma is encapsulated benign tumors arising from nerve cell. Of which ancient schwannoma is one of five variants. Intraparotid facial nerve schwannoma is been documented sporadical throught the medical literature, althought a few ancient schwannomas have been reported in different locations in the head and neck region. In this report, a 31 year old man patient with an misunderstanding tumor of the parotid gland is described and the histopathologic exam was performed to diagnosed the schwannoma.
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Neoplasias de los Nervios Craneales/cirugía , Errores Diagnósticos , Enfermedades del Nervio Facial/cirugía , Neurilemoma/cirugía , Glándula Parótida/inervación , Adenoma Pleomórfico/diagnóstico , Adulto , Neoplasias de los Nervios Craneales/diagnóstico , Neoplasias de los Nervios Craneales/diagnóstico por imagen , Enfermedades del Nervio Facial/diagnóstico , Enfermedades del Nervio Facial/diagnóstico por imagen , Humanos , Imagen por Resonancia Magnética , Masculino , Neurilemoma/diagnóstico , Neurilemoma/diagnóstico por imagen , Neoplasias de las Glándulas Salivales/diagnósticoRESUMEN
The present study was designed to verify the correlation between tinnitus and temporomandibular joint dysfunction.86 consecutive patients were enrolled in the study, all affected by subjective tinnitus without hearing impairment, from both genders, age between 18 and 60 years old. The final number of patients included in the study was 55. All patients received a temporo-mandibular joint examination. All the patients were asked to rate the severity of their symptoms before and after treatment using a VAS scale and the Tinnitus Handicap Inventory (THI) and they followed a standardized protocol for the investigation of tinnitus. All the subjects were monitored by the same researcher and they underwent the same splint treatment. The comparison between pre- and posttreatment phase scores showed in patients with predisposition of TMD and with TMD a statistically significant decrease of THI and VAS values. The characteristics of tinnitus and the degree of response to treatment confirmed the relationship between tinnitus and TMD. The authors believe that, when the most common causes of tinnitus, such as otologic disorders and neurological diseases are excluded, it is correct to evaluate the functionality of the temporo-mandibular joint and eventually treat its pathology to obtain tinnitus improvement or even resolution.
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Trastornos de la Articulación Temporomandibular/complicaciones , Acúfeno/complicaciones , Adolescente , Adulto , Audiometría/métodos , Protocolos Clínicos , Estudios Controlados Antes y Después , Femenino , Estudios de Seguimiento , Humanos , Imagen por Resonancia Magnética/métodos , Masculino , Anamnesis , Persona de Mediana Edad , Ferulas Oclusales , Radiografía Panorámica/métodos , Rango del Movimiento Articular/fisiología , Trastornos de la Articulación Temporomandibular/clasificación , Trastornos de la Articulación Temporomandibular/terapia , Acúfeno/clasificación , Acúfeno/terapia , Tomografía Computarizada por Rayos X/métodos , Escala Visual Analógica , Adulto JovenRESUMEN
Traditional plants for plastic separation in homogeneous products employ material physical properties (for instance density). Due to the small intervals of variability of different polymer properties, the output quality may not be adequate. Sensing technologies based on hyperspectral imaging have been introduced in order to classify materials and to increase the quality of recycled products, which have to comply with specific standards determined by industrial applications. This paper presents the results of the characterization of two different plastic polymers--polyethylene terephthalate (PET) and polyvinyl chloride (PVC)--in different phases of their life cycle (primary raw materials, urban and urban-assimilated waste and secondary raw materials) to show the contribution of hyperspectral sensors in the field of material recycling. This is accomplished via near-infrared (900-1700 nm) reflectance spectra extracted from hyperspectral images acquired with a two-linear-spectrometer apparatus. Results have shown that a rapid and reliable identification of PET and PVC can be achieved by using a simple two near-infrared wavelength operator coupled to an analysis of reflectance spectra. This resulted in 100% classification accuracy. A sensor based on this identification method appears suitable and inexpensive to build and provides the necessary speed and performance required by the recycling industry.
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Tereftalatos Polietilenos/clasificación , Cloruro de Polivinilo/clasificación , Reciclaje , Tereftalatos Polietilenos/aislamiento & purificación , Cloruro de Polivinilo/aislamiento & purificación , Espectroscopía Infrarroja CortaRESUMEN
Pleomorphic adenoma is a common benign salivary gland tumor, which represents about 66 % of benign neoplasms of the salivary glands. Although it can occur in any salivary gland, it is most frequently found in the parotid. Pleomorphic adenomas are renowned for their cytomorphological and architectural heterogeneity that are characterized by intermixed epithelial and mesenchymal-like components. We report a rare case of pleomorphic adenoma of the parotid gland with prevalent schwannoma-like features mimicking a benign schwannoma. Microscopically the tumor showed a prevalence (about 95 %) of schwannoma-like areas with focal (about 5 %) epithelial component with tubular organization. The tumor showed positive immunoexpression for cytokeratin, S-100 protein, and focal expression of p63, CD10 and smooth muscle actin. To the best of our knowledge only six cases of schwannoma-like pleomorphic adenoma have been reported in the literature. The differential diagnosis between this entity and neurogenic and myogenic tumors is discussed.
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Adenoma Pleomórfico/patología , Diagnóstico Diferencial , Neoplasias de la Parótida/patología , Adulto , Biomarcadores de Tumor/análisis , Femenino , Humanos , Inmunohistoquímica , Neurilemoma/patologíaRESUMEN
Studies on blast neurotrauma have focused on investigating the effects of exposure to free-field blast representing the simplest form of blast threat scenario without considering any reflecting surfaces. However, in reality personnel are often located within enclosures or nearby reflecting walls causing a complex blast environment, that is, involving shock reflections and/or compound waves from different directions. The purpose of this study was to design a complex wave testing system and perform a preliminary investigation of the intracranial pressure (ICP) response of rats exposed to a complex blast wave environment (CBWE). The effects of head orientation in the same environment were also explored. Furthermore, since it is hypothesized that exposure to a CBWE would be more injurious as compared to a free-field blast wave environment (FFBWE), a histological comparison of hippocampal injury (cleaved caspase-3 and glial fibrillary acidic protein (GFAP)) was conducted in both environments. Results demonstrated that, regardless of orientation, peak ICP values were significantly elevated over the peak static air overpressure. Qualitative differences could be noticed compared to the ICP response in rats exposed to simulated FFBWE. In the CBWE scenario, after the initial loading the skull/brain system was not allowed to return to rest and was loaded again reaching high ICP values. Furthermore, results indicated consistent and distinct ICP-time profiles according to orientation, as well as distinctive values of impulse associated with each orientation. Histologically, cleaved caspase-3 positive cells were significantly increased in the CBWE as compared to the FFBWE. Overall, these findings suggest that the geometry of the skull and the way sutures are distributed in the rats are responsible for the difference in the stresses observed. Moreover, this increase stress contributes to correlation of increased injury in the CBWE.
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Cabeza/fisiología , Ondas de Choque de Alta Energía , Presión Intracraneal , Animales , Fenómenos Biomecánicos , Traumatismos por Explosión , Caspasa 3/metabolismo , Proteína Ácida Fibrilar de la Glía/metabolismo , Hipocampo/metabolismo , Masculino , Ratas , Ratas Sprague-DawleyRESUMEN
According to the literature and World Health Organization, elderly people are specified as persons older than 65 years of age. The authors believe that the indication for surgery patients over 65 is based on the restoration of functionality and the aesthetics. The behavior of the surgeon has to change with patients aged older than 75 years where the restoration of function and, therefore, a good quality of life is far more important than the aesthetic restoration. In a retrospective study of 1022 patients consecutively hospitalized at Maxillofacial department in Roma, Università "Sapienza," the patients older than 75 years were analyzed. During this period, the data of all patients undergoing treatment because of trauma-related injuries were collected. Data were registered regarding etiology, localization of the injury, surgical treatment ratio, medium average stay, age, and sex distribution. Surgical treatment in these patients should be driven by the general condition of health whenever possible; reduction of facial fractures should be guided by the need to return a good quality of life for the patients. The goal of this study was to analyze a new group of population, people older than 75 years, that is, a real new and growing group of population.
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Traumatismos Maxilofaciales/cirugía , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Calidad de Vida , Fracturas Craneales/cirugía , Resultado del TratamientoRESUMEN
Since an increasing number of returning military personnel are presenting with neurological manifestations of traumatic brain injury (TBI), there has been a great focus on the effects resulting from blast exposure. It is paramount to resolve the physical mechanism by which the critical stress is being inflicted on brain tissue from blast wave encounters with the head. This study quantitatively measured the effect of head orientation on intracranial pressure (ICP) of rats exposed to a shock wave. Furthermore, the study examined how skull maturity affects ICP response of animals exposed to shock waves at various orientations. Results showed a significant increase in ICP values in larger rats at any orientation. Furthermore, when side-ICP values were compared to the other orientations, the peak pressures were significantly lower suggesting a relation between ICP and orientation of the head due to geometry of the skull and location of sutures. This finding accentuates the importance of skull dynamics in explaining possible injury mechanisms during blast. Also, the rate of pressure change was measured and indicated that the rate was significantly higher when the top of the head was facing the shock front. The results confirm that the biomechanical response of the superior rat skull is distinctive compared to other areas of the skull, suggesting a skull flexure mechanism. These results not only present insights into the mechanism of brain injury, but also provide information which can be used for designing more effective protective head gear.
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Traumatismos por Explosión/fisiopatología , Lesiones Encefálicas/fisiopatología , Cabeza , Presión Intracraneal , Animales , Traumatismos por Explosión/etiología , Tamaño Corporal , Lesiones Encefálicas/etiología , Ondas de Choque de Alta Energía/efectos adversos , Masculino , Postura , Ratas , Ratas Sprague-Dawley , Cráneo/anatomía & histología , Cráneo/fisiologíaRESUMEN
Arterial injuries in infants are rare and in most cases are of iatrogenic origin as a consequence of catheterization, venipuncture or arterial blood sampling. These lesions require an accurate, noninvasive clinical diagnosis and prompt exploration and reconstruction using microvascular techniques to restore perfusion and to avoid morbidity and even mortality. We present a 3-day-old infant with a brachial artery thrombosis by a white thrombus as a consequence of an unsuccessful attempt to introduce an intravascular catheter. A microvascular reconstruction was performed, with complete restoration of the blood flow. Any suspected vascular injury needs immediate clinical and diagnostic assessment in order to avoid potential life-threatening complications. Surgery is mandatory in case of extensive arterial injuries, in case of inadequate distal blood supply or in case of progressive worsening of ischemic clinical findings.
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Arteria Braquial/lesiones , Cateterismo/efectos adversos , Trombosis/etiología , Humanos , Recién NacidoRESUMEN
Anophthalmia and micro-orbitism due to infections, traumatic events, and oncologic disease can occur both in adulthood and in childhood. After restoring the volume of the socket surgically or using an expander, concurrent forniceal expansion with expanding conformer should be maintained. We created a new type of conformer that is possible to fit even in very reduced or very irregularly shaped socket. It is formed by 3 acrylic portions connected by metallic clumps that represent an intrinsic mechanism of expansion. The 3 acrylic portions could be modeled on the shape of the individual patient socket while the metal elements allow a thrust in 3 directions. The positioning of this conformer does not need any surgical treatment and it is possible to fit it in an ambulatory manner; it is shaped on the individual patient and is then available in most cases that occur.
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Anoftalmos/cirugía , Enucleación del Ojo , Lesiones Oculares/cirugía , Ojo Artificial , Implantes Orbitales , Dispositivos de Expansión Tisular , Humanos , Masculino , Persona de Mediana EdadRESUMEN
We report the results of monolateral dual kidney transplantation with grafts with multiple arteries. Among the 42 monolateral DKT performed in a seven-yr period, 12 (28.5%) patients received renal grafts with multiple arteries. In six patients, the accessory arteries were anastomosed end-to-side or side-to-side on the aortic patch. In six patients, with three or more accessory arteries, a vascular reconstruction with an inferior vena cava patch was performed, before implanting the kidney. There were no intraoperative complications in the entire series, and there were no immediate vascular complications. Vascular reconstruction of kidneys with multiple arteries may be performed safely even in monolateral dual kidney transplantation. Inferior vena cava may be an attractive alternative in vascular reconstruction for kidneys with multiple arteries.
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Trasplante de Riñón/mortalidad , Trasplante de Riñón/métodos , Procedimientos de Cirugía Plástica/mortalidad , Complicaciones Posoperatorias , Arteria Renal/cirugía , Procedimientos Quirúrgicos Vasculares/mortalidad , Anciano , Anastomosis Quirúrgica , Femenino , Estudios de Seguimiento , Rechazo de Injerto/mortalidad , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Tasa de SupervivenciaRESUMEN
A combined experimental and numerical study was conducted to determine a method to elucidate the biomechanical response of a head surrogate physical model under air shock loading. In the physical experiments, a gel-filled egg-shaped skull/brain surrogate was exposed to blast overpressure in a shock tube environment, and static pressures within the shock tube and the surrogate were recorded throughout the event. A numerical model of the shock tube was developed using the Eulerian approach and validated against experimental data. An arbitrary Lagrangian-Eulerian (ALE) fluid-structure coupling algorithm was then utilized to simulate the interaction of the shock wave and the head surrogate. After model validation, a comprehensive series of parametric studies was carried out on the egg-shaped surrogate FE model to assess the effect of several key factors, such as the elastic modulus of the shell, bulk modulus of the core, head orientation, and internal sensor location, on pressure and strain responses. Results indicate that increasing the elastic modulus of the shell within the range simulated in this study led to considerable rise of the overpressures. Varying the bulk modulus of the core from 0.5 to 2.0 GPa, the overpressure had an increase of 7.2%. The curvature of the surface facing the shock wave significantly affected both the peak positive and negative pressures. Simulations of the head surrogate with the blunt end facing the advancing shock front had a higher pressure compared to the simulations with the pointed end facing the shock front. The influence of an opening (possibly mimicking anatomical apertures) on the peak pressures was evaluated using a surrogate head with a hole on the shell of the blunt end. It was revealed that the presence of the opening had little influence on the positive pressures but could affect the negative pressure evidently.
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Geles , Plásticos/química , Cráneo/fisiología , Algoritmos , Animales , Fenómenos Biomecánicos , Lesiones Encefálicas/fisiopatología , Simulación por Computador , Módulo de Elasticidad , Diseño de Equipo , Humanos , Ensayo de Materiales , Modelos Teóricos , Presión , Programas Informáticos , Propiedades de SuperficieRESUMEN
Traumatic brain injuries (TBI) caused by improvised explosive devices (IEDs) affect a significant percentage of surviving soldiers wounded in Iraq and Afghanistan. The extent of a blast TBI, especially initially, is difficult to diagnose, as internal injuries are frequently unrecognized and therefore underestimated, yet problems develop over time. Therefore it is paramount to resolve the physical mechanisms by which critical stresses are inflicted on brain tissue from blast wave encounters with the head. This study recorded direct pressure within the brains of male Sprague-Dawley rats during exposure to blast. The goal was to understand pressure wave dynamics through the brain. In addition, we optimized in vivo methods to ensure accurate measurement of intracranial pressure (ICP). Our results demonstrate that proper sealing techniques lead to a significant increase in ICP values, compared to the outside overpressure generated by the blast. Further, the values seem to have a direct relation to a rat's size and age: heavier, older rats had the highest ICP readings. These findings suggest that a global flexure of the skull by the transient shockwave is an important mechanism of pressure transmission inside the brain.
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Traumatismos por Explosión/complicaciones , Lesiones Encefálicas/etiología , Encéfalo/fisiopatología , Ondas de Choque de Alta Energía/efectos adversos , Presión Intracraneal/fisiología , Animales , Modelos Animales de Enfermedad , Masculino , Ratas , Ratas Sprague-DawleyRESUMEN
PURPOSE: The objective of this study was to describe the orthognathic surgery techniques for the treatment of occlusal anomalies in those patients who underwent complex maxillomandibular reconstruction with bony free flap. MATERIALS AND METHODS: The authors describe their personal technique developed over years of experience with reconstruction of mandibular defects with bony free flaps. RESULTS: The outcomes in these patients who were treated according to our surgical planning were completely satisfying, with a 100% stability of the treated bones. CONCLUSIONS: Orthognathic procedure on bony free flaps for the reconstruction of mandibular defects is nowadays accepted. Patients who underwent major mandibular destruction due to oncologic disease or trauma outcomes can now benefit from this technique.
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Mandíbula/cirugía , Enfermedades Mandibulares/cirugía , Procedimientos Quirúrgicos Ortognáticos/métodos , Procedimientos de Cirugía Plástica/métodos , Colgajos Quirúrgicos , Peroné/trasplante , Humanos , Ilion/trasplante , Mandíbula/diagnóstico por imagen , Enfermedades Mandibulares/diagnóstico por imagen , Osteotomía/métodos , RadiografíaRESUMEN
As early as the 1950's, Gurdjian and colleagues (Gurdjian et al. 1955) observed that brain injuries could occur by direct pressure loading without any global head accelerations. This pressure-induced injury mechanism was "forgotten" for some time and is being rekindled due to the many mild traumatic brain injuries attributed to blast overpressure. The aim of the current study was to develop a finite element (FE) model to predict the biomechanical response of rat brain under a shock tube environment. The rat head model, including more than 530,000 hexahedral elements with a typical element size of 100 to 300 microns was developed based on a previous rat brain model for simulating a blunt controlled cortical impact. An FE model, which represents gas flow in a 0.305-m diameter shock tube, was formulated to provide input (incident) blast overpressures to the rat model. It used an Eulerian approach and the predicted pressures were verified with experimental data. These two models were integrated and an arbitrary Lagrangian-Eulerian (ALE) fluid-structure coupling algorithm was then utilized to simulate the interaction of the shock wave with the rat head. The FE model-predicted pressure-time histories at the cortex and in the lateral ventricle were in reasonable agreement with those obtained experimentally. Further examination of the FE model predictions revealed that pressure amplification, caused by shock wave reflection at the interface of the materials with distinct wave impedances, was found in the skull. The overpressures in the anterior and posterior regions were 50% higher than those at the vertex and central regions, indicating a higher possibility of injuries in the coup and contrecoup sites. At an incident pressure of 85 kPa, the shear stress and principal strain in the brain remained at a low level, implying that they are not the main mechanism causing injury in the current scenario.
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Traumatismos por Explosión/complicaciones , Lesiones Encefálicas/etiología , Encéfalo/fisiopatología , Simulación por Computador , Análisis de Elementos Finitos , Cabeza/fisiopatología , Aceleración , Aire , Animales , Fenómenos Biomecánicos , Traumatismos por Explosión/fisiopatología , Lesiones Encefálicas/fisiopatología , Modelos Animales de Enfermedad , Explosiones , Presión , Ratas , Estrés MecánicoRESUMEN
Facial deficit diseases are corrected by biomaterial implantation. The ideal biomaterial should be easy to implant and remove and simple to be identified by a low-dose radiation and low-cost radiologic technique. The purpose of this work was to evaluate ultrasonography (US) as a technique in monitoring biomaterial status after operation. In the last 3 years, for this study we used polyethylene porosus and polyacrylamide. Our study included 300 patients grouped accordingly as follows: malformative syndromes, degenerative syndromes, and esthetic problems, results of skull-facial traumas, and whether they are treated in the early phase and or the late phase. In this paper, we describe the better 15 clinical cases for their excellent result and for their variety of US images. Ultrasonography has been shown as an excellent way to visualize clinical features and a possible pathologic process of an implanted biomaterial; it is a noninvasive, low-radiation and low-cost dose radiologic technique. Reconstruction in facial deficit diseases needs adequate biomaterial to implant and a careful patients observation, that is, both clinical and radiologic. Ultrasonography is a fundamental component of the follow up of implanted biomaterial patients.