Preface

It is my pleasure to write a Preface to Fibro Cartilaginous Eustachian Tube - Middle Ear Cleft, edited by Bernard Ars. Professor Ars has dedicated his career to improving our understanding of the gas exchange in the middle ear and mastoid, as it relates to ear disease. He has assembled a group of internationally recognized authorities in the areas of middle ear and mastoid gas exchange, middle ear disease, eustachian tube anatomy and physiology, and innovators in the surgical management of eustachian tube dysfunction.

Acute and chronic ear disease continues to be one of the leading diseases of childhood. Understanding eustachian tube function and management remains one of the most important aspects in controlling inflammatory ear disease. Chronic ear disease requires elaborate surgical interventions designed to bypass eustachian tube dysfunction and/or poor mastoid aeration, since surgical management of the eustachian tube has been elusive. Our understanding of the ear and hearing continues to expand at record pace, as auditory neuroscientists discover the fundamental molecular structure and function of the auditory system. The cochlear implant has revolutionized the treatment of deafness. In contrast, the complexity of eustachian tube pathophysiology is only just beginning to be appreciated.

This book provides a detailed analysis of contemporary knowledge on the morphology, physiology, and gas exchange function of the eustachian tube, middle ear, and mastoid. Newer diagnostic tests, such as sono tubometry, tubomanometry, and endoscopic video-analysis, are also described. Finally, a selection of innovative surgical management strategies for eustachian tube dysfunction is presented. The clinical impact of these diagnostic tools and surgical management options still requires the test of time, as well as investigation by others. This text provides the trainee, clinician, and researcher with the opportunity to acquire state-of-the-art information in a single volume. I am certain that this is just the beginning of our knowledge of ways in which to improve the management of one of the long-standing chronic conditions that result in hearing loss and more serious sequellae. 

Bruce J Gantz, MD, FACS
Professor and Head 
Brian F McCabe Distinguished Chair in 
Otolaryngology-Head and Neck Surgery
The University of Iowa
Iowa City, Iowa 

Introduction

The fibrocartilaginous eustachian tube is part of a system of contiguous organs including the nose, palate, rhinopharynx, and middle ear cleft. The middle ear cleft consists of the tympanic cavity, which includes the bony eustachian tube (pro-tympanum) and the mastoid air cells system. The tympanic cavity and mastoid cells are interconnected and allow for gas circulation with pressure regulation and gaseous exchanges.

The fibrocartilaginous eustachian tube is not a simple tube, in fact, but rather a complex organ consisting of a lumen with its mucosa, cartilage, surrounding soft tissue, peritubal muscles (i.e., tensor and levator veli palatine, salpingopharyngeus and tensor tympani), and superior bony support, the sphenoid sulcus.

We believe that the principal roles of the fibrocartilaginous eustachian tube could be the optimization of middle ear sound transmission and protection of the inner ear structures. These roles are aided by maintenance of the indispensable balance of pressure variations within the middle ear cleft, relative to ambient pressures. Given that the fibrocartilaginous eustachian tube links the protected sterile environment of the middle ear cleft to the potentially hostile outside world, it must provide three additional specific organic functions, as follows:

• mechanical protection against rhinopharyngeal secretions and pathogenic microorganism reflux, as well as against retrograde propagation of vocal sounds;

• local immune defence; and

• mucociliary clearance into the rhinopharynx of secretions produced in the middle ear cleft and carried out in its inferior part. 

How we should define and measure 'good tubal function' is still far from apparent! There is a wide range of normal variation, and we still lack the necessary tests for discriminating between normal and abnormal function with clinically relevant correlation.

Tubal function is an intrinsic and important component of the middle ear pressure regulation system. In the event of tubal dysfunction, coordination between the various components fails, and a cascade of consequences ensues.

When we talk about 'tubal dysfunction', we exclude obvious anatomical malformations (e.g., cleft palate) and extrinsic peritubal obstructions, such as what might result from compression by a tumor. Tubal dysfunction may involve an abnormality at any stage of the dilatation cycle, including:

• initial opening

• dilating and

• closing processes

The types of dysfunction can be subdivided into: 

• obstructive dysfunction: 
  including mucosal and submucosal edema, inflammation and infections, and

• dynamic dysfunction:
  including disorders of one or more of the muscles involved in the above three processes, and/or disorders of the pressure and gas mixture, receptors of the entire system.

At the present time, there is no consensus of opinion on this, and 'tubal dysfunction' remains an abstruse concept! It is our hope to present a critical and contemporary evaluation of this subject and to provide information which will lead to further advancement in this field.

The objective of this book is to bring together clinicians and basic scientists interested in tubal function, with special emphasis on tubal dysfunction and chronic otitis media. Fruitful collaboration between the various disciplines can do much to improve the diagnosis and therapy of tubal dysfunction and middle ear disease.

The book is organized into five sections covering: history, morphology and physiology, clinical tubal functional evaluation, and therapeutic management of tubal dysfunction. It brings together a well-represented faculty of experts who supply overviews and present topical state-of-the-art information within their respective areas. We are indebted to those authors who accepted our challenge and made a positive, realistic contribution to this critical clinical topic.

Another goal of this book is to encourage clinicians, residents, and young investigators to become familiar with unsolved research challenges. It has been set up as an informative work of analysis and reference, intended for future use in both fundamental and applied research or, in other words, as an educational tool.

Bernard Ars 

Table of Contents

Preface, Bruce J. Gantz

Introduction, Bernard Ars

History

The history of the anatomy and physiology of the fibrocartilaginous eustachian tube, Albert Mudry

Phylogeny

Phylogeny of hearing and auditory structures, Vasant Oswal and N. Apte

Morphology and physiology

Developmental morphology of the middle ear cleft, Bernard Ars and Nicole Ars-Piret

Development of the fibrocartilaginous eustachian tube, Bernard Ars

Opening and closure of the fibrocartilaginous eustachian tube, Dennis S. Poe

Balance of pressure variations in the middle ear cleft, Bernard Ars

Inflammatory mediators, gas composition, and middle ear epithelial pathophysiology: an experimental approach using cell culture, Philippe Herman

Eustachian tube function and mucosal diffusion: their mutual relationship to middle ear pressure regulation, Jef J.S.Mulder

Middle ear cleft pressure: continuous 24-hour measurements, Bo Tideholm

Contribution of eardrum pars flaccida and pars tensa volume displacement to pressure regulation in the middle ear cleft, Joris J.J. Dirckx and Willem F. Decraemer

Fibrocartilaginous eustachian tube and cholesteatoma, Th. Stark, S. Dazert and Holger Sudhoff

Paraclinical tubal functional evaluation

Sonotubometry, John Hamilton

Tubomanometry, Bernard Ars and Joris J.J. Dirckx

Tubomanometry and pathology, Dominique Estève

Slow motion endoscopic video-analysis of the fibrocartilaginous eustachian tube, Dennis S. Poe

Therapeutic management of tubal dysfunction

Tubal dysfunction: etiology and middle ear pathology, Benoît Gratacap

Eustachian tube surgery. I. Laser eustachian tuboplasty. II. Patulous eustachian tube surgical management, Oskar B. Kujawski

Re-adaptation of the baroreceptors of the fibrocartilaginous eustachian tube and middle ear cleft by means of the Kinétube®, Dominique Estève

Tubal therapy: its foundations, modalities and efficiency, Françoise Estienne

Index of authors