Tympanic Endoscopy

At VE the posterior sinus tympani can be seen under the eminence of the facial nerve canal and posterior to the oval window. The sinus tympani appears as a parietal depression whose landmarks are given by the ponticulus (superior), the subiculum (inferior-anterior), the pyramidal crest and eminence (posterior-lateral), and the promontory (anterior). Thomassin (1994) describes three types of sinus tympani on the basis of the feasibility of trans-tympanic endoscopy, but their morphology can be easily recognized also at VE sinus tympani of easy exploration, characterized by a simple depression of the tympanic wall sinus tympani of difficult exploration, represented by a depression of the wall that continues into a deep canal through the tympanic wall and opens into the retrotympanum with a little orifice intermediate sinus tympani, with deep canal and large orifice. 

Virtual Endoscopy (Clinical Applications) The Study of the Tympanic Cavity 141... 

Recently, interest in the CT study of the middle ear has been renewed by detailed endoscopic studies of this region performed during interventions with dedicated devices this technique has been called transtympanic endoscopy, since it requires the perforation of the tympanic membrane. 

The history of real endoscopy of the middle ear was started in 1967 by Zini when he tried to visualize the middle ear using a system of micromirrors, which allowed the exploration of the retrotympanum. This method, called indirect microtympanoscopy, is still used in clinical practice. Mer et al. (1967) introduced the fiberoptic endoscope into the tympanic cavity through a perforation of the tympanic membrane. Marquet and Boedts D (1975) described an endoscopic technique based on the use of a 1.7-mm... 

Transtympanic endoscopy can be used as a diagnostic tool or as guidance for otosurgical interventions. In the first case the easy access of the external auditory canal allows the visualization of the tympanic membrane, a barrier between the endoscope and the middle ear only the presence of a pathologic or surgical (miringotomy) perforation permits a limited exploration of the tympanic cavity. 

The protympanum represents the anterior part of the tympanic cavity that includes the pharyngo-tympanic tube. The superior border of the tube divides the protympanum from the sinus epitympani. The inferior border separates the tube from the internal carotid artery. The protympanum is easy to explore with either transtympanic endoscopy or VE (Fig. 10.2c). 

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