Relevant anatomical details in rats regarding otologic research / Detalles anatómicos relevantes en ratas para la investigación otológica

SUMMARY: The objective of the study was to provide a detailed anatomical description of the rat's ear anatomy that will prove insightful to different experimental otologic surgical procedures regardless of scope. Three male Wistar rats were enrolled in the study. Candidates were screened for systemic and otologic pathology. External ear canal endoscopy was carried out with a 30˚ rigid endoscope through an image capture system. Middle ear anatomical elements were analyzed under stereomicroscopy. 3D computer tomography image reconstruction was realized with a micro-CT to describe the anatomy. Image data from all three rats were analyzed. Anatomical annotations and surgical exposure recommendations were added for key elements. The most relevant images from all three rats were selected for representation. Detailed visualization of the structural elements of the tympanic cavity were clearly visible: promontory, round window, stapedial artery, stapes, incus, and tympanic membrane were all constant findings. We describe a step wise ventral surgical approach of the middle and inner ear for which we found that the clavotrapezius muscle was a reliable landmark. For the transtympanic approach the endoscopic transcanal access was an easy and reliable method for which a detailed anatomical representation was depicted. Further, anatomical similarities to humans were observed by stereomicroscopy and Micro-CT imaging reiterating that the rat model is suitable for otologic research. The endoscopic approach to the tympanic membrane is comfortable and less expensive than a microscope. The tendon of the clavotrapezius muscle can be a reliable landmark for discovering the tympanic bulla when considering a ventral approach. 3D Micro-CT reconstruction allows intact evaluation of the samples, simultaneously being a diagnostic and also a learning tool.

RESUMEN: El objetivo de este trabajo fue proporcionar una descripción anatómica detallada de la anatomía del órgano vestíbulococlear de la rata que resultará útil para diferentes procedimientos quirúrgicos otológicos experimentales, independientemente del alcance. En el estudio se usaron tres ratas Wistar macho. Los ejemplares fueron evaluados por patología sistémica y otológica. La endoscopía del meato acústico externo se realizó con un endoscopio rígido de 30˚ a través de un sistema de captura de imágenes. Los elementos anatómicos del oído medio se analizaron bajo estereomicroscopía. La reconstrucción de la imagen de tomografía computarizada en 3D se realizó con un micro-CT para describir la anatomía. Se analizaron los datos de imagen de las tres ratas. Se agregaron anotaciones anatómicas y recomendaciones de exposición quirúrgica para elementos clave. Las imágenes más relevantes de las tres ratas fueron seleccionadas para su representación. La visualización detallada de los elementos estructurales de la cavidad timpánica era claramente visible: promontorio timpánico, ventana coclear, arteria estapedial, estapedio, yunque y membrana timpánica eran hallazgos constantes. Describimos un abordaje quirúrgico ventral escalonado del oído medio e interno para el cual encontramos que el músculo clavotrapecio era un punto de referencia confiable. Para el abordaje transtimpánico, el acceso transcanal endoscópico fue un método fácil y confiable para el cual se describió una representación anatómica detallada. Además, se observaron similitudes anatómicas con los humanos mediante estereomicroscopía e imágenes Micro-CT, lo que reitera que el modelo de rata es adecuado para la investigación otológica. El abordaje endoscópico de la membrana timpánica es cómodo y menos costoso que un microscopio. El tendón del músculo clavotrapecio puede ser un punto de referencia fiable para descubrir la bulla timpánica cuando se considera un abordaje ventral. La reconstrucción 3D Micro- CT permite la evaluación intacta de las muestras, siendo simultáneamente una herramienta de diagnóstico y también de aprendizaje.

2D browsing software and 3D PDF of canine ear based on real color sectioned images / Software de navegación 2D y PDF en 3D del oído canino basado en imágenes seccionadas en color real

Dog ear is very important because of disease vulnerability. Therefore, gross anatomy and sectional anatomy on CT and MRI of the dog ear should be mastered by veterinarian. The purpose of this research was to present the digital atlases which high quality sectioned images and 3D models of detailed structures of dog ear could be displayed freely. In the sectioned images of a female beagle, ear structures were reconstructed by surface modeling to make 3D models. The sectioned images and 3D models were put into the browsing software and PDF file, respectively. Using the browsing software and the PDF file, gross and radiological anatomy of dog ear could be learned easily and accurately. The auditory tube of a dog was placed anterior to the tympanic cavity unlike human. The tensor tympani muscle of a dog was connected to the dorsal wall of the tympanic cavity with the malleus. No remarkable difference in the auditory ossicles, semicircular ducts, facial nerve, and endolymphatic duct was observed between dogs and humans. The software and the PDF file will be provided to other researchers freely to help contribute to veterinary research and education.

La oreja del perro es importante debido a la vulnerabilidad de enfermedad. Por lo tanto, el veterinario debe conocer plenamente la anatomía macroscópica y la anatomía seccional en la TC y la RM del oído del perro. El objetivo de esta investigación fue presentar los atlas digitales que podían mostrar imágenes seccionadas de alta calidad y modelos 3D de estructuras detalladas de orejas de perro. En las imágenes seccionadas de una hembra Beagle, las estructuras de las orejas se reconstruyeron mediante modelado de superficie con el objetivo de crear modelos 3D. Las imágenes seccionadas y los modelos 3D se colocaron en un software de navegación y un archivo PDF. El uso de software de navegación y el archivo PDF permiten un aprendizaje fácil y preciso de la anatomía macroscópica y radiológica de la oreja de perro. El músculo tensor del tímpano de un perro estaba conectado a la pared dorsal de la cavidad timpánica con el martillo. No se observaron diferencias notables en los huesecillos auditivos, los conductos semicirculares, el nervio facial y el conducto endolinfático entre perros y humanos. El software y el archivo PDF estarán disponibles libremente para los investigadores para ayudar en la investigación y educación veterinaria.

Surgeon oriented preoperative radiologic evaluation in cochlear implantation - our experience with a proposed checklist

Introduction: Preoperative temporal bone imaging studies have been routinely performed prior to cochlear implantation. Radiologists need to report these examinations with special focus on the surgeon's expectations. Objectives: To provide a basic structured format, in the form of a checklist, for reporting preoperative computed tomography (CT) and to its clinical impact on operative findings. Methods: The preoperative temporal bone CT scans of 47 patients were analyzed and reported according to the proposed checklist. Intraoperative assessment of mastoidectomy, posterior tympanotomy and round window access was done by the surgeon in a blinded fashion and were correlated with the radiological findings to assess its significance. Results: The proposed radiological checklist was reliable in assessing operative difficulty during cochlear implantation. Contracted mastoid and lower tegmen position were associated with a greater difficulty of the cortical mastoidectomy. Presence of an air cell around the facial nerve (FN) was predictive of easier facial recess access exposure. Facial nerve location and posterior external auditory canal (EAC) wall inclination were predictive of difficult round window (RW) accessibility. Conclusion: Certain parameters on the preoperative temporal bone CT scan may be useful in predicting potential difficulties encountered during the key steps involved in cochlear implant surgery (AU)

A Study of the Congenital Anomalies of the Ear with Special Reference to Microtia.

Congenital abnormalities of the ear is rare. It has been estimated that it occurs once in 2,00,000 births. Children with this malformation are usually sent to plastic surgery Dept. In bilateral cases they are often referred to E N T Dept. because of the hearing loss and the treatment becomes a combined problem. The outstanding role of radiological revaluation of the external, middle and internal ear apparatus is of paramount importance. Methods & Materials : The patients attending E.N.T., Out Patient Department was utilized as case materials. Besides clinical study, Plain X-Ray and C.T. plays an important role. C.T and plain X-Rays including lateral oblique mastoid views, Submentovertical view, Stenver’s views, Towne’s view, would be taken for assessment of external, middle and internal ear development. Whenever necessary, views for Mandible shall be recorded also. Aims and Objectivies : Objective of the present study is to classify congenital anomalies and to record the type of disabilities with the help of radiological investigations. Systemic study of incidence of such cases shall be recorded.