Histomorphometric study of the normal middle ear mucosa. Preliminary results supporting the gas-exchange function in the postero-superior part of the middle ear cleft.

This study concerns the distance between the centre of gravity of blood vessels and the basement membrane of the middle ear cleft mucosa. The measurements were performed perpendicular to the long axis of the cross-section of the vessels, and revealed a significant difference between two regions of the middle ear cleft. At the level of the postero-superior part (epitympanum, aditus ad antrum, mastoid antrum and highest part of the mastoid air cells system), the distance between the blood vessels and the basement membrane of the mucosa was statistically shorter than in the antero-inferior part of the middle ear cleft. This indicates a privileged function of gaseous exchange of the postero-superior part of the middle ear cleft and may divide the middle ear cleft into different functional parts.

Morpho-functional partition of the middle ear cleft.

The observation of an inter-attico-tympanic diaphragm in the middle ear (ME) cleft and the functional histology of the mucosa lead to a concept of ME morpho-functional partition. There are two separate compartments: an antero-inferior one, principally devoted to the muco-ciliary clearance function, and a postero-superior one, more devoted to the gas exchange function. With this concept of partition the mechanisms involved in the pathogeny of "otitis media" can be better understood.

[Pockets of tympanic membrane retraction]. / Bolsas de retracción de la membrana timpánica.

The pathogenesis of tympanic retraction pockets is analyzed. Middle-ear pressure and the behavior of the lamina propria and stratified squamous epithelium of the tympanic membrane were considered. Predisposing factors are discussed. Conservative surgical treatment is recommended for retraction pockets that are not adhered to the walls of the middle ear. Radical surgery should be reserved for adhered pockets. The management of mastoid cavities is discussed.

Preservation of cochlear function after extensive labyrinthine destruction.

We report a case of hearing preservation after removal of the semicircular canals and discuss the possible explanations for the mechanisms of preservation of hearing after removal of the labyrinth. We hope to promote the perspectives and possibilities of functional surgery of the inner ear and for tumors of the cerebellopontine angle.

Tympanic membrane. Retraction pocket.

The author attempts to analyse the pathogenesis of the retraction pocket. Middle ear pressure, behaviour of both the tympanic membrane lamina propria and the stratified squamous epithelium are considered. Predisposing factors are presented. A conservative surgical treatment is suggested in cases of non-fixed retraction pockets; a radical surgical treatment is reserved for the fixed pockets. The management of mastoid cavities is discussed.

Allograft myringoplasty.

The tympanic membrane allograft myringoplasty is used for the radical treatment of chronic middle ear disease and the repair of tympanic perforations which are sequellae of the chronic middle ear conditions. In the first part, basic principles, tissue bank and surgical procedures, are explained in detail. The second part shows that this technique ensures not only total eradication of the pathology, but is favoured by the specific morpho-, physio- and bio-compatibilities of the allograft.

Applied embryology and post-natal morphology of the human tympanic membrane.

This article deals with the morphological as well as histological changes of the tympanic membrane and bone from early embryological life until mature age. An overview of the continuous changes is given with reference to pertinent clinical implications.

Preoperative computed tomography in patients requiring a bone-anchored hearing aid.

A preoperative computed tomography technique, "Dentascan" or "Dentatool", was used to find the optimal site for implant installation in patients requiring a bone-anchored hearing aid. The technique is demonstrated in a patient with bilateral bone conduction hearing loss who was treated with bilateral bone-anchored hearing aids.

Middle ear pressure balance under normal conditions. Specific role of the middle ear structure.

The mechanisms which govern under normal conditions the balance of middle ear pressure are discussed. The regular periodic active process of gas transfer through the Eustachian tube, the steady gas diffusion between middle ear and blood compartment and finally the pressure buffer role played by the mastoid are successively considered.

Tympanic membrane retraction pockets. Etiology, pathogeny, treatment.

The author describes the morphological behaviour of the tympanic membrane, undergoing long term negative pressure in the middle ear cavities. He explains the viscoelastic properties of the tympanic membrane lamina propria, in cases of retraction pockets. He analyses the preferential weakness of some well localized parts of the tympanic membrane and defends an accurate treatment to avoid this pathology.

Tympano-ossicular allograft tympanoplasty. Physiocompatibility.

The aim of the work is to point out some physiological aspects of the tympano-ossicular allograft as well of its receptor site. The typical fibrous weft of the membrane which closely sticks to the handle of the malleus, on one side, and in the sulcus, on the other side, gives an optimal layout and ensures the stability of the graft. The presence and flexibility of the joints enable the ossicular chain of the allograft to provide protection for the inner ear.

Tympano-ossicular allografts following J. Marquet: the evaluation of a school.

The experience with 1.645 transplantation procedures by ENT surgeons, trained in tympano-ossicular allograft technique following J. Marquet, is reported. The grafts originated from different tissue banks. The anatomical and functional results one year postoperatively were analysed. There appeared to be no statistical differences between tissue banks, nor between surgeons. Contrary to the anatomical results, functional differences existed between allograft tympanoplasties and some types of allograft tympano-ossiculoplasties. It was concluded that the routine use of allograft tympano-ossiculoplasty offers a major tool in otological surgery and that it is the method of choice by the ENT surgeons trained by the School of J. Marquet.

On the etiology of hearing loss in a population of 155 institutionalized children.

In this paper we present the results of an etiological study in 155 hearing-impaired children and young adults, born between 1960 and 1984, inmates of the IRSA institute (Royal Institute for Deaf and Blind children). Special reference to genetic factors was given. One third of the inmates of this institute were children of immigrants, the majority Italians and North-Africans. The study revealed the following classification for the Belgian pupils: hereditary deafness 22.9%; acquired deafness 44.9% and deafness of unknown origin 32.1%; in the group of immigrants, it was 39.1%, 45.6% and 15.2%, respectively. Six of the 45 patients with a genetic form of deafness presented a distinct syndrome, Usher syndrome (2 patients) being the most frequent. Autosomal dominant inheritance was present more often in the deaf population than in the hearing-impaired population (hearing loss below 80 db), but the difference was not statistically significant. Even after 1980 congenital rubella remained the most frequent exogenous factor causing congenital deafness and, furthermore, we documented for the first time in a retrospective study cytomegalovirus infection as a cause of hearing loss. Atypical retinal abnormalities not related to congenital rubella syndrome were found in 10 inmates by systematic ophthalmological examination: 7 in the unknown group, 1 in the genetic group and 2 in the acquired (meningitis) group.

[A battery of tests for evaluating minimal speech perception. Initial experimental results]. / Batterie d'évaluation de la perception minimale de la parole (batterie EPMP). Premiers résultats expérimentaux.

Different tests for evaluating the residual speech perception in deaf people are presented. First results obtained with different groups of deaf people are discussed.

[Huschke's foramen]. / Le foramen de Huschke.

Morphological analysis of the tympanic part of the temporal bone has lead us to comment a particular structure: the foramen of Huschke. This foramen is founded during the embryological development and results from the growth and fusion of two tympanic tubercles. The foramen of Huschke normally closes up like a diaphragm before the age of five years. It may however, persist in a few rare cases (2/300).

[Prosthesis of the middle ear. Criteria for the shape and physical properties]. / Prothèse d'oreille moyenne. Critères de forme et propriétés physiques.

The aim of this study is to point out some anatomical and physiological characteristics concerning the tympano-ossicular system, in the view to contribute to the elaboration of an optimal prosthesis of the middle ear.

Tympano-ossicular allografts: morphology and physiology.

The purpose of our work was to analyze the morphology and the physiology of the tympano-ossicular allografts used for reconstruction of the middle ear. The first section of the article concerns the removal and preservation of the allografts. We then describe the results of the morphologic observations concerning the tympanic membrane, the fibrocartilaginous ring, meatal skin, and ossicular chain. The demonstration of some characteristics of the physiology of the allograft supports the results of this study.