Septic thrombosis of the internal jugular vein: Lemierre's syndrome revisited

OBJECTIVES/HYPOTHESIS Study of the clinical evolution of a primary ear, nose, and throat infection complicated by septic thrombophlebitis of the internal jugular vein. STUDY DESIGN Retrospective case-control study. PATIENTS AND METHODS From 1998 to 2010, 23 patients at our institution were diagnosed with a septic thrombosis of the internal jugular vein. Diagnostics included microbiologic analysis and imaging such as computed tomography, magnetic resonance imaging, and ultrasound. Therapy included broad-spectrum antibiotics, surgery of the primary infectious lesion, and postoperative anticoagulation. The patients were retrospectively analyzed. RESULTS The primary infection sites were found in the middle ear (11), oropharynx (8), sinus (3), and oral cavity (1). Fourteen patients needed intensive care unit treatment for a mean duration of 6 days. Seven patients were intubated, and two developed severe acute respiratory distress syndrome. An oropharynx primary infection site was most prone to a prolonged clinical evolution. Anticoagulation therapy was given in 90% of patients. All 23 patients survived the disseminated infection without consecutive systemic morbidity. CONCLUSION In the pre-antibiotic time, septic internal jugular vein thrombophlebitis was a highly fatal condition with a mortality rate of 90%. Modern imaging techniques allow early and often incidental diagnosis of this clinically hidden complication. Anticoagulation, intensive antibiotic therapy assisted by surgery of the primary infection site, and intensive supportive care can reach remission rates of 100%. LEVEL OF EVIDENCE 3b. Laryngoscope, 2014.

Mechatronic feasibility of minimally invasive, atraumatic cochleostomy

Robotic assistance in the context of lateral skull base surgery, particularly during cochlear implantation procedures, has been the subject of considerable research over the last decade. The use of robotics during these procedures has the potential to provide significant benefits to the patient by reducing invasiveness when gaining access to the cochlea, as well as reducing intracochlear trauma when performing a cochleostomy. Presented herein is preliminary work on the combination of two robotic systems for reducing invasiveness and trauma in cochlear implantation procedures. A robotic system for minimally invasive inner ear access was combined with a smart drilling tool for robust and safe cochleostomy; evaluation was completed on a single human cadaver specimen. Access to the middle ear was successfully achieved through the facial recess without damage to surrounding anatomical structures; cochleostomy was completed at the planned position with the endosteum remaining intact after drilling as confirmed by microscope evaluation.

A Neuromonitoring Approach to Facial Nerve Preservation During Image-guided Robotic Cochlear Implantation.

HYPOTHESIS A multielectrode probe in combination with an optimized stimulation protocol could provide sufficient sensitivity and specificity to act as an effective safety mechanism for preservation of the facial nerve in case of an unsafe drill distance during image-guided cochlear implantation. BACKGROUND A minimally invasive cochlear implantation is enabled by image-guided and robotic-assisted drilling of an access tunnel to the middle ear cavity. The approach requires the drill to pass at distances below 1 mm from the facial nerve and thus safety mechanisms for protecting this critical structure are required. Neuromonitoring is currently used to determine facial nerve proximity in mastoidectomy but lacks sensitivity and specificity necessaries to effectively distinguish the close distance ranges experienced in the minimally invasive approach, possibly because of current shunting of uninsulated stimulating drilling tools in the drill tunnel and because of nonoptimized stimulation parameters. To this end, we propose an advanced neuromonitoring approach using varying levels of stimulation parameters together with an integrated bipolar and monopolar stimulating probe. MATERIALS AND METHODS An in vivo study (sheep model) was conducted in which measurements at specifically planned and navigated lateral distances from the facial nerve were performed to determine if specific sets of stimulation parameters in combination with the proposed neuromonitoring system could reliably detect an imminent collision with the facial nerve. For the accurate positioning of the neuromonitoring probe, a dedicated robotic system for image-guided cochlear implantation was used and drilling accuracy was corrected on postoperative microcomputed tomographic images. RESULTS From 29 trajectories analyzed in five different subjects, a correlation between stimulus threshold and drill-to-facial nerve distance was found in trajectories colliding with the facial nerve (distance <0.1 mm). The shortest pulse duration that provided the highest linear correlation between stimulation intensity and drill-to-facial nerve distance was 250 μs. Only at low stimulus intensity values (≤0.3 mA) and with the bipolar configurations of the probe did the neuromonitoring system enable sufficient lateral specificity (>95%) at distances to the facial nerve below 0.5 mm. However, reduction in stimulus threshold to 0.3 mA or lower resulted in a decrease of facial nerve distance detection range below 0.1 mm (>95% sensitivity). Subsequent histopathology follow-up of three representative cases where the neuromonitoring system could reliably detect a collision with the facial nerve (distance <0.1 mm) revealed either mild or inexistent damage to the nerve fascicles. CONCLUSION Our findings suggest that although no general correlation between facial nerve distance and stimulation threshold existed, possibly because of variances in patient-specific anatomy, correlations at very close distances to the facial nerve and high levels of specificity would enable a binary response warning system to be developed using the proposed probe at low stimulation currents.

Vista general del modelado del sistema auditivo

El objetivo principal del presente proyecto es proporcionar al ingeniero de telecomunicaciones una visión general de las técnicas que se utilizan en el modelado del sistema auditivo. El modelado del sistema auditivo se realiza con los siguientes objetivos: a) Interpretar medidas directas, b)unificar el entendimiento de diferentes fenómenos, c) guiar estrategias de amplificación para suplir pérdidas auditivas y d) tener predicciones experimentalmente comprobables de comportamientos, con diferentes niveles de complejidad. En este trabajo se tratarán y explicarán brevemente las diferentes técnicas utilizadas para modelar las partes del sistema auditivo, desde las analogías electroacústicas, modelos biofísicos, binaurales, hasta la implementación de filtros auditivos mediante procesado de señal. Podemos concluir que el modelado mediante analogías electroacústicas permite una rápida implementación y entendimiento, pero tiene ciertas limitaciones. Las simulaciones mediante análisis numéricos son precisas y de gran utilidad tanto para del oído medio como para el interno. El procesado de señal es el procedimiento más completo y utilizado ya que permite modelar oído externo y medio además de permitir la implementación de filtros cocleares muy precisos y coherentes con la realidad incluyéndolos en modelos perceptivos. ABSTRACT. The main aim of the Project is to provide the Telecommunications Engineer an overview about the approaches for modelling the auditory system. The auditory system modelling is done for the next objectives: a) Interpret direct measures, b) Understand different phenomena c) get strategies of amplification for hearing impaired people and d) Obtain testable predictions experimentally about some behaviors with different complexity levels. Inside this document, several approaches about modeling of the auditory system parts will be explained: analog circuits, biophysics models, binaural models, and auditory filters made through signal processing. In conclusion, analog circuits are made quickly and they are easier to understand but they have many limitations. Simulations through numerical analysis are accurate and useful in middle and inner ear models. Signal processing is the more versatile approach because it lets to make a model of external and middle ear and then it allows to make complex auditory filters. Perceptive models can be made entirely through this method.

Cochlear mechanisms from a phylogenetic viewpoint

The hearing organ of the inner ear was the last of the paired sense organs of amniotes to undergo formative evolution. As a mechanical sensory organ, the inner-ear hearing organ's function depends highly on its physical structure. Comparative studies suggest that the hearing organ of the earliest amniote vertebrates was small and simple, but possessed hair cells with a cochlear amplifier mechanism, electrical frequency tuning, and incipient micromechanical tuning. The separation of the different groups of amniotes from the stem reptiles occurred relatively early, with the ancestors of the mammals branching off first, approximately 320 million years ago. The evolution of the hearing organ in the three major lines of the descendents of the stem reptiles (e.g., mammals, birds-crocodiles, and lizards-snakes) thus occurred independently over long periods of time. Dramatic and parallel improvements in the middle ear initiated papillar elongation in all lineages, accompanied by increased numbers of sensory cells with enhanced micromechanical tuning and group-specific hair-cell specializations that resulted in unique morphological configurations. This review aims not only to compare structure and function across classification boundaries (the comparative approach), but also to assess how and to what extent fundamental mechanisms were influenced by selection pressures in times past (the phylogenetic viewpoint).

Plasticity in the neural coding of auditory space in the mammalian brain

Sound localization relies on the neural processing of monaural and binaural spatial cues that arise from the way sounds interact with the head and external ears. Neurophysiological studies of animals raised with abnormal sensory inputs show that the map of auditory space in the superior colliculus is shaped during development by both auditory and visual experience. An example of this plasticity is provided by monaural occlusion during infancy, which leads to compensatory changes in auditory spatial tuning that tend to preserve the alignment between the neural representations of visual and auditory space. Adaptive changes also take place in sound localization behavior, as demonstrated by the fact that ferrets raised and tested with one ear plugged learn to localize as accurately as control animals. In both cases, these adjustments may involve greater use of monaural spectral cues provided by the other ear. Although plasticity in the auditory space map seems to be restricted to development, adult ferrets show some recovery of sound localization behavior after long-term monaural occlusion. The capacity for behavioral adaptation is, however, task dependent, because auditory spatial acuity and binaural unmasking (a measure of the spatial contribution to the “cocktail party effect”) are permanently impaired by chronically plugging one ear, both in infancy but especially in adulthood. Experience-induced plasticity allows the neural circuitry underlying sound localization to be customized to individual characteristics, such as the size and shape of the head and ears, and to compensate for natural conductive hearing losses, including those associated with middle ear disease in infancy.

Surdez induzida pelo trauma acústico

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

Disfunção tubária em contexto de corpo estranho e rinolitíase nas fossas nasais : caso clínico

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

Effects of the fibers distribution in the human eardrum: A biomechanical study

The eardrum separates the external ear from the middle ear and it is responsible to convert the acoustical energy into mechanical energy. It is divided by pars tensa and pars flaccida. The aim of this work is to analyze the susceptibility of the four quadrants of the pars tensa under negative pressure, to different lamina propria fibers distribution. The development of associated ear pathology, in particular the formation of retraction pockets, is also evaluated. To analyze these effects, a computational biomechanical model of the tympano-ossicular chain was constructed using computerized tomography images and based on the finite element method. Three fibers distributions in the eardrum middle layer were compared: case 1 (eardrum with a circular band of fibers surrounding all quadrants equally), case 2 (eardrum with a circular band of fibers that decreases in thickness in posterior quadrants), case 3 (eardrum without circular fibers in the posterior/superior quadrant). A static analysis was performed by applying approximately 3000Pa in the eardrum. The pars tensa of the eardrum was divided in four quadrants and the displacement of a central point of each quadrant analyzed. The largest displacements of the eardrum were obtained for the eardrum without circular fibers in the posterior/superior quadrant.

Effects of the fibers distribution in the human eardrum: A biomechanical study

The eardrum separates the external ear from the middle ear and it is responsible to convert the acoustical energy into mechanical energy. It is divided by pars tensa and pars flaccida. The aim of this work is to analyze the susceptibility of the four quadrants of the pars tensa under negative pressure, to different lamina propria fibers distribution. The development of associated ear pathology, in particular the formation of retraction pockets, is also evaluated. To analyze these effects, a computational biomechanical model of the tympano-ossicular chain was constructed using computerized tomography images and based on the finite element method. Three fibers distributions in the eardrum middle layer were compared: case 1 (eardrum with a circular band of fibers surrounding all quadrants equally), case 2 (eardrum with a circular band of fibers that decreases in thickness in posterior quadrants), case 3 (eardrum without circular fibers in the posterior/superior quadrant). A static analysis was performed by applying approximately 3000Pa in the eardrum. The pars tensa of the eardrum was divided in four quadrants and the displacement of a central point of each quadrant analyzed. The largest displacements of the eardrum were obtained for the eardrum without circular fibers in the posterior/superior quadrant.

Tympanometric findings in children at school entry: A normative study

This study presents tympanometric normative data for Australian children at school entry in view of the lack of age-specific population-based data for this group. Participants were 327 children (164 boys, 163 girls) aged between 5 and 6 years, who had no history of middle ear infection, and passed pure-tone screening at 20 dB HL. Normative values for static admittance (SA), ear canal volume (ECV), tympanometric peak pressure, tympanometric width (TW) and tympanometric gradient were established. Based on these normative data, the use of the ASHA (1997) guidelines for medical referral, in which ECV > 1.0 ml in the presence of a flat tympanogram, SA < 0.3 ml, or TW > 200 daPa may not provide the best criteria for Australian children aged between 5 and 6 years. If SA < 0.3 ml were used instead of SA < 0.16 ml, a greater proportion of Australian children would have failed tympanometry, thus increasing the false alarm rate.

Tympanometric norms for Chinese schoolchildren

Current tympanometric norms have acknowledged the relevance of age as,in influencing factor. However, little attention has been afforded to other potentialities such its the non-pathological effects of gender, ear asymmetry, and racial heritage. This study aimed to examine normative tympanometric findings in a large sample of Chinese schoolchildren. Using a Madsen 901 Middle Ear Analyzer, data was collected from 269 children (538 ears), ranging in age from 6.2-12.7 years (mean = 9.4 years, SD = 1.7), in Jiangsu province. Descriptive statistics were calculated for the parameters of equivalent car canal volume (chi = 1.03, SD = 0.25, 90% = 0.68-1.46), peak compensated static acoustic admittance (chi = 0.58, SD = 0.34, 90% = 0.26-1.13), tympanometric width (chi = 112, SD=36, 90% = 62-156), and peak pressure (chi = -25, SD = 30, 90% = -85-+10). Statistically significant car asymmetry and grade/age effects were estabished, although differences found were minor. In comparison with past studies in Caucasian paediatric populations, the Chinese normative data displayed minimal disparities.

Classroom implications of recent research into literacy development: from predictors to assessment

We outline how research into predictors of literacy underpins the development of increasingly accurate and informative assessments. We report three studies that emphasize the crucial role of speech and auditory skills on literacy development throughout primary and secondary school. Our first study addresses the effects of early childhood middle ear infections, the potential consequences for speech processing difficulties and the impact on early literacy development. Our second study outlines how speech and auditory skills are crucially related to early literacy in normally developing readers, whereas other skills such as motor, memory and IQ are only indirectly related. Our third study outlines the on-going impact of phonological awareness on reading and wider academic achievement in secondary-school pupils. Finally, we outline how teachers can use the current research to inform them about which assessments to conduct, and how to interpret the results. Copyright © 2008 John Wiley & Sons, Ltd.

Non-auditory Influences on the Auditory Periphery

Once thought to be predominantly the domain of cortex, multisensory integration has now been found at numerous sub-cortical locations in the auditory pathway. Prominent ascending and descending connection within the pathway suggest that the system may utilize non-auditory activity to help filter incoming sounds as they first enter the ear. Active mechanisms in the periphery, particularly the outer hair cells (OHCs) of the cochlea and middle ear muscles (MEMs), are capable of modulating the sensitivity of other peripheral mechanisms involved in the transduction of sound into the system. Through indirect mechanical coupling of the OHCs and MEMs to the eardrum, motion of these mechanisms can be recorded as acoustic signals in the ear canal. Here, we utilize this recording technique to describe three different experiments that demonstrate novel multisensory interactions occurring at the level of the eardrum. 1) In the first experiment, measurements in humans and monkeys performing a saccadic eye movement task to visual targets indicate that the eardrum oscillates in conjunction with eye movements. The amplitude and phase of the eardrum movement, which we dub the Oscillatory Saccadic Eardrum Associated Response or OSEAR, depended on the direction and horizontal amplitude of the saccade and occurred in the absence of any externally delivered sounds. 2) For the second experiment, we use an audiovisual cueing task to demonstrate a dynamic change to pressure levels in the ear when a sound is expected versus when one is not. Specifically, we observe a drop in frequency power and variability from 0.1 to 4kHz around the time when the sound is expected to occur in contract to a slight increase in power at both lower and higher frequencies. 3) For the third experiment, we show that seeing a speaker say a syllable that is incongruent with the accompanying audio can alter the response patterns of the auditory periphery, particularly during the most relevant moments in the speech stream. These visually influenced changes may contribute to the altered percept of the speech sound. Collectively, we presume that these findings represent the combined effect of OHCs and MEMs acting in tandem in response to various non-auditory signals in order to manipulate the receptive properties of the auditory system. These influences may have a profound, and previously unrecognized, impact on how the auditory system processes sounds from initial sensory transduction all the way to perception and behavior. Moreover, we demonstrate that the entire auditory system is, fundamentally, a multisensory system.

Internal carotid arterial canal size and scaling in Euarchonta: Re-assessing implications for arterial patency and phylogenetic relationships in early fossil primates.

Primate species typically differ from other mammals in having bony canals that enclose the branches of the internal carotid artery (ICA) as they pass through the middle ear. The presence and relative size of these canals varies among major primate clades. As a result, differences in the anatomy of the canals for the promontorial and stapedial branches of the ICA have been cited as evidence of either haplorhine or strepsirrhine affinities among otherwise enigmatic early fossil euprimates. Here we use micro X-ray computed tomography to compile the largest quantitative dataset on ICA canal sizes. The data suggest greater variation of the ICA canals within some groups than has been previously appreciated. For example, Lepilemur and Avahi differ from most other lemuriforms in having a larger promontorial canal than stapedial canal. Furthermore, various lemurids are intraspecifically variable in relative canal size, with the promontorial canal being larger than the stapedial canal in some individuals but not others. In species where the promontorial artery supplies the brain with blood, the size of the promontorial canal is significantly correlated with endocranial volume (ECV). Among species with alternate routes of encephalic blood supply, the promontorial canal is highly reduced relative to ECV, and correlated with both ECV and cranium size. Ancestral state reconstructions incorporating data from fossils suggest that the last common ancestor of living primates had promontorial and stapedial canals that were similar to each other in size and large relative to ECV. We conclude that the plesiomorphic condition for crown primates is to have a patent promontorial artery supplying the brain and a patent stapedial artery for various non-encephalic structures. This inferred ancestral condition is exhibited by treeshrews and most early fossil euprimates, while extant primates exhibit reduction in one canal or another. The only early fossils deviating from this plesiomorphic condition are Adapis parisiensis with a reduced promontorial canal, and Rooneyia and Mahgarita with reduced stapedial canals.