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Biomedical subjects

G Bremond

Publications and source records attributed to G Bremond.

At least 19 recordsLinked to original sources
PubMed1992

[Vestibular compensation. Clinical value of its dynamic study].

Vestibular compensation consists of all the processes of neurological reorganization that allow recovering balance after a unilateral vestibular lesion. According to its etiology, the peripheral lesion may be more or less severe, may evolve more or less rapidly, and be more or less reversible. Therefore, it will have a characteristic "pattern" in time, which enables us to classify the kinetic aspects of peripheral pathology. Vestibular compensation, which responds to these variations in the sensitivity of the posterior labyrinth, is a slowly progressive adaptation mechanism. This compensation will progressively reduce the musculotonic asymmetry affecting the postural muscles and the eye muscles, and it can therefore be studied on the basis of the velocity of the spontaneous nystagmus as measured in the dark. We can then define a "vestibular compensation rate" at a given moment. To achieve this, a diagram (E. UMER) is proposed to represent the lesion and the rate of vestibular compensation and to study their mutual relationships. The dynamic study of vestibular compensation and the measurement of its "time constant" than have threefold merits for diagnosis, prognosis and treatment.

Adaptation, Physiological↗
PubMed1991

Vestibular neurotomy by retrosigmoid approach: technique, indications, and results.

During the past 15 years, 96 retrosigmoid vestibular neurotomies have been used in the surgical management of incapacitating Meniere's disease for the control of vertigo and preservation of hearing. This posterior approach of the pontocerebellar angle gives the best view on the acousticofacial nerve bundle, through a 2 x 2 cm suboccipital craniotomy immediately behind the mastoid and sigmoid sinus. Then the vestibular nerve is easily identified, separated from the cochlear nerve and sectioned, the facial nerve not being at risk, as it lies much deeper. Actually, the majority of authors agree that vestibular neurotomy is the most effective surgical treatment in relieving disabling vertigo (96% of cases) with serviceable hearing, but few surgeons know that the retrosigmoid approach is simpler and more reliable than the middle fossa or retrolabyrinthine approaches, with a low incidence of complications. The purpose of this paper is to emphasize the routine use of the retrosigmoid approach.

Aged↗
PubMed1991

[Anatomo-pathology of cholesteatoma].

The authors, from their own histopathological studies and from an overview of otological literature focus the controversial problems about the so-called disease cholesteatoma. The history of cholesteatoma has been marked out by pathologic data which, initially caused the cholesteatoma to be identified as a keratinized squamous tumor. This misnomer will however be retained because of it long-established usage. "Skin in the wrong place" in the middle ear summarizes this clinical entity. Electron microscopic observations provide arguments in favour of the migratory theory and the invasion of the epidermis from the bottom of the external ear canal into the middle ear cavity (identical fine morphology between skin and cholesteatoma, presence of Langerhans and Merkel cells, sharp junction between the advancing front of the cholesteatoma and the middle ear mucosa). Recent immunohistological techniques allow consideration of cholesteatoma as a self-induced inflammatory process in response to tissular and cellular conflicts. A cholesteatoma could be merely a non-healing wound process and a disease of epidermal growth control occurring in the middle ear space. The logical principles governing cholesteatoma surgery, suggested by these biological considerations, are: total removal of cholesteatoma matrix, prevention of cholesteatoma recurrence by a careful respect of the barrier separating the middle ear mucosa from the skin-lined bony external ear canal, maintenance of good healing conditions for both mucosa in a closed well-ventilated middle ear and epidermis in a harmonious anatomical external canal.

Cell Movement↗
PubMed1990

[Retraction pockets, pathological entity?].

Retraction pockets are not a pathological entity per se but take after various ear diseases, with which they share the same morphological eardrum alterations. The authors believe that any holistic evaluation of retraction pockets, as though these were forming a single group of like pathogenic origin, i.e., tubal dysfunction, would be artificial and raise therapeutic problems. The statistical analysis of the causes for retraction pocket formation provides little information. Otologists are still looking into chronic otitis media and cholesteatoma as a possible, long-suspected, unproved etiology. Electron microscopy and, more particularly, istological-enzymological analyses of mounts prepared by the authors have shown, in some cases, the anomalous presence, in the pocket, of Langerhans' cells, which the authors consider as strongly indicative of cholesteatoma. While confirming the clinical diagnosis, anatomopathological examination allows to differentiate poor-prognosis retraction pockets from benign ones. The pathogenesis of these pockets is still poorly understood. It is the authors' contention that tympanic invagination is more likely traceable to some biopathological/biochemical phenomenon than to occupational mechanical disorders involving the tube. The clinical characteristics of retraction pockets are the basis for their classification into three groups, according to their evolutional tendency. Thus, developing cholesteatomas bear a poor prognosis; sequelae of benign otitis are associated with small risk; lastly, there is a small group of pockets the evolution of which is hard to specify. The authors believe that such differentiation between retraction pockets is mandatory to have a clear picture of therapeutic indications, and to assess the various outcomes.

Cholesteatoma↗
PubMed1989

[Diagnostic and therapeutic problems in dissociated forms of Menière's disease].

The authors report the cases of 5 subjects who presented with incapacitating vertigo which was attributed to a dissociated form of Meniere's disease. They stress the difficulty, in these circumstances, in making a precise diagnosis which can only in fact be confirmed with the benefit of a longer follow up. They stress the value of systematically combining frequency analysis with measurement of maximal slow phase velocity during vestibular testing. This allowed better precision in terms of topographical diagnosis. All subjects underwent vestibular neurotomy via the retro-sigmoid approach. The procedure did not alter hearing and compensation occurred within the usual delay. The question therefore arises as to when is the best time to intervene in patients presenting with vertigo of peripheral origin with preserved hearing.

Audiometry↗
PubMed1984

[The fronto-supra-ethmoidal approach. Its value in cerebrospinal rhinorrhea].

A supra-ethmoidal approach was used to treat cerebrospinal fluid rhinorrhea secondary to anterior fractures of the base of the skull. After an internal orbital incision, the anterior wall of the frontal sinus is removed and the posterior wall of this sinus trephined in the internal region of its horizontal portion in order to expose the meninges covering the roof of the first ethmoidal space. Dissection is continued within the space towards the anterior extremity of the apophysis of the crista galli against which the fibrous band issuing from the anterior ethmoidal opening is sectioned. The dura mater is then separated from the cribriform plate of the ethmoid up to the jugum sphenoidale posteriorly, while progressively coagulating and sectioning the nerve and connective tissue network attached to the cribriform plate. This freeing of the dura mater exposes the meningeal fistula and allows its liberation from its bony adhesions. A fragment of epicranium removed from the frontal bone is spread between the dura mater and the cribriform plate in order to cover it completely. A drain is then introduced into the nasofrontal canal and the anterior wall of the frontal sinus replaced in position. The advantages of this technique are: the operation is simple, it allows good exposure of the fistula, and since the bony support of the ethmoid is not destroyed the meningeal opening can be easily obstructed.

Cerebrospinal Fluid Rhinorrhea↗
PubMed1977

[Adhesive otitis: 30 surgical cases (author's transl)].

Adhesive otitis accounts for 3% of all cases of chronic otitis. It is characterized by the attachment of the entire epidermal layer of the drum to the inner wall of the cavity. Three causative factors are identified: abnormal permeability of the auditory tube; absence of the fibrous layer of the tympanic membrane; a predisposing milieu. This is a very different condition from tympanosclerosis and its scleroadhesive sequelae. It can, however, be associated with cholesteatoma. An analysis of 30 cases in which surgery was performed points to the real progress brought about by the use of tympanic homografts. One problem remains: permanent aeration of the new tympanic cavity.

Adolescent↗