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Biomedical subjects

M Négrevergne

Publications and source records attributed to M Négrevergne.

15 recordsLinked to original sources
PubMed2005

[Reinforcing tympanoplasty with cartilage mosaic (differences from the palisade technique)].

OBJECTIVES: To demonstrate the interest of cartilage mosaic tympanoplasty in the reconstruction of the tympanic membrane. MATERIALS AND METHODS: Retrospective series of 103 patients; the authors analyzed their results after cartilage mosaic tympanoplasty, with a mean follow up of 3.5 years (3 to 7 years). They explain the surgical technique in detail. The average gain was calculated on the difference of the pre-and post-operative thresholds in air conduction on the four frequencies 500 Hz, 1000 Hz, 2000 Hz, 4000 Hz. RESULTS: The authors detail and analyze their anatomical and audiologic results. The total rate of closing of the tympanic membrane is 93.2%, accounting for 96 perforations closed among 103. A tympanic retraction sitting apart from the reinforced zone was noted in 0.97%, representative only one case of 103. Then the total rate of success is 92.23%, representing 8 failures of 103. The average pre- and post-operative air bone gap were 26.5 dB and 14.6 dB. The average gain was 12.5 dB (extremes of 0 dB to 40 dB). CONCLUSION: The authors show the great reliability of cartilage mosaic tympanoplasty to reconstruct the tympanic membrane. They widen the indications with all types of tympanoplasties. Especially with the recurrent perforations, and the perforations evolving in an inflammatory context and/or dysfunction of the Eustation tube. Their results show a major interest to use this technique in the anterior and inferior perforations, and whatever the ossicular chain status.

Adolescent↗
PubMed2005

[Vertigo and pathology of the cerebello-pontine angle].

Many pathologies of the cerebello-pontine angle can induce vertigo or dizziness. Usually they are due to benign or malignant tumors. Pathophysiology of this vertigo involve lesion of the labyrinth with erosion, of the endolymphatic sac by invasion or compression, or directly by lesion of the vestibular nerve like in vestibular schwannomas. The vestibular nerve can also be injured by extrinsic compression like in meningiomas. Finally very big tumors can be compressive on the cerebellum or on the brainstem inducing also dizziness. Vertigo is often an important symptom of cerebello-pontine angle tumors. In association with others it will guide the diagnosis. Nevertheless, auditory evoked potentials, video-nystagmography, and otolithic evoked potentials are very important to determine exactly if the vestibular nerve is injured and if there are signs of central compression before surgery.

Cerebellar Neoplasms↗
PubMed2005

[Vertigo and pathology of the cerebellospinal system].

Central vertigo is most often expressed by a feeling of dizziness, non or badly systematized, but it can also appear, more seldom, like an isolated acute vertigo or associated to other neurological signs. A precise clinical exam can lead to evidence essential clinical informations (significant ataxia, neurological signs, gaze nystagmus, pursuit anomaly,...). Almost all acute lesions of central vestibular pathways, as for the peripheral ones, lead to a harmonious vestibular syndrome. The vascular lesion of the vertebro-basilar territory and multiple sclerosis are two main causes to it. The pseudo-labyrinthine forms are essentially described in occlusion infarcts of the AICA and PICA, but a hematoma can lead to the same picture; the diagnostic of multi- or monosymptomatic forms with a peripheral lesion is often very difficult, the classical classification of the central and peripheral vestibular syndromes has become obsolete and should be abandoned.

Central Nervous System Diseases↗
PubMed2003

[Video-nystagmography and vibration test in the diagnosis of vestibular schwannoma. Review of 100 cases].

OBJECTIVE: To evaluate informations given by the combination of videonystagmography (VNG) including vibratory tests and auditory brainstem responses (ABR) in patients suffering vestibular schwannoma (VS) and try to find the most conclusive test(s). Combination of different functional tests is supposed to improve diagnosis and preoperative evaluation and precise indication for magnetic resonance imaging (MRI) facing audiological and vestibular symptoms. MATERIAL AND METHOD: A prospective study of 100 patients with VS. All patients underwent a preoperative work-up including complete audiometry, auditory brainstem response (ABR) and videonystagmography (VNG). VNG protocol included caloric testing, rotatory tests, oculometry tests (saccade testing, optokinetic testing) and spontaneous and gaze-evoked nystagmus. From these six tests a score of positivity could be set, from 0 to 6. RESULTS: The vibratory test is non invasive and easy to realize. Were observed: 1/ a good sensitivity in vibratory test to elicit nystagmus in this context. 2/ a good correlation between subliminal rotatory chair tests and vibratory tests 3/ a better control of caloric testing using vibratory test. 4/ a good but deficient sensitivity of ABR alone with regard to VS (95%) 5/ an increase of sensitivity of VNG when coupling it with ABR and using as a criterion the score of positivity: no patient had all tests negative. CONCLUSION: The vibratory test is a non-invasive, fast examination with an easy execution. It reinforces VNG-ABR association screening power to diagnose VS. It constitutes, combined to caloric testing a good tool to diagnose and evaluate unilateral vestibular weakness.

Adult↗
PubMed2003

Otoplasty for prominent ears in children. The technique adopted in the Portmann Institute.

The Otoplasty technique adopted in the Portmann Institute is a simple rapid technique that maintains the natural contours of the auricle with minimal risk of infection. The technique involves excision of a large ellipse of skin from the mastoid surface of the auricle and reflection of remaining skin to the edge of the helix. The subcutaneous and muscular tissues on the mastoid bone are excised and the mastoid surface of the auricular cartilage scored with monopolar diathermy. After haemostasis, the wound is closed using continuous long-term absorbable sutures. A dressing and bandage are applied and the child is monitored for 10 days. A head bandage is applied at night for one month with use of a sun-screen cream on the scar at daytime.

Academic Medical Centers↗
PubMed1999

[Middle ear physiology].

The middle ear forms part of the sound transformer mechanism, together with the outer ear and the conducting system of the inner ear. An intermediate sensory organ, sensitive to acoustic vibration, and linked to the inner ear, the middle ear made its appearance during the period of adaptation of marine creatures to a terrestrial habitat; its presence is therefore a phylogenetic requirement. It is classical to ascribe three functions to the middle ear: the transmission of acoustic vibrations from the tympanic membrane to the cochlea, impedance matching between the air in the external auditary meatus and the labyrinthine fluids, and protection of the inner ear by means of the acoustic reflex. If the classical mechanical explanation has been able to explain its function, the conceptualization of its physiology in terms of energy allows an even better understanding, as well as providing and explanation for the paradoxes which arise in clinical practice when the classical model is used.

Ear, Middle↗
PubMed1999

[Multi-frequency tympanometry in experimentally-induced cochlear lesions in chinchillas and guinea pigs].

OBJECTIVES: To establish that susceptance-conductance tympanograms at a probe-tone frequency of 2 kHz reflects the status of the annular ligament (AL) and through it of the cochlea. METHODS: Experimental study in 5 chinchillas and 22 guinea pigs. Six validating experiments were used: blockages of the stapes and of the round window membrane (RWM), fistula of the RWM, fluid removal from the cochlea, injection of saline in the scala tympani (ST) and acoustic trauma (AT). Quantitative data (mean values of Y226, FR, Y2000, G2000 and B2000) and shape of the curves were analyzed before and immediately after lesions were done. RESULTS: Guinea pig was the most convenient provided bulla was vented and the same tip was used along the experiments. Only the shape of the curves are discriminant: 1/a supplementary sharp peak, centered around negative pressures, is observed in Y/G tympanograms in every case of RWM fistulas and in some case of AT. 2/injection of saline into ST induces immediate and reproducible Y2000, G2000, et B2000 curves modifications. 3/RWM and stapes blockages provoke foreseeable stiffening and sharpening of the tympanograms at 2 kHz. 4/on the contrary, fluid removal from the cochlea induces multiple peaks curves. CONCLUSIONS: Experimentally-induced modifications at the AL either direct (stapes blockage) or indirect by AT or decrease/increase of pressure load at the cochlear interface at the footplate result in noticeable, constant, reproducible changes of curves registered at 2 kHz. The stapes behaves both as the plotter of the curves and the interpreter of the inner ear pressure.

Acoustic Impedance Tests↗
PubMed1999

[Multi-frequency impedance measurement and Meniere's disease. Analysis of the results of TEFLAG].

We present today our preliminary results of the TEFLAG test performed on 58 patients suffering from Meniere's disease. This test completed in 1993 has already led to a 4-stage classification of noise induced hearing losses. On the one hand, it is based on the morphological study of susceptance B curves, and on the other hand, on the study of the resonant frequency (RF) of the annular ligament of the stapes, provided by a multifrequential impedancemeter. The endolymphatic hydrops coming with the Meniere's disease practically always cohabits in the intercritical period with the decrease of the perilymphatic pressure of the scala vestibuli, which is shown in the morphology of Stage IV curves especially, and the decrease of the annular ligament rigidity. Inversely, during the vertigo or around, we mainly have stage I curves, and an increase of the stapes annular ligament resonant frequency (RF), testifying the labyrinthic hydrops, which is the physiopathological essence of the Meniere's disease.

Acoustic Impedance Tests↗
PubMed1997

[Genetic deafness and Pendred syndrome].

The authors present two cases of genetic deafness in a brother and his sister. The girl has shown to suffer from a deafness belonging to Pendred's syndrome; in this case, the development of hearing symptomatology since her puberty is presented as an aggravated crisis of deafness and tinnitus coinciding with her menstruation, what suggests a possible endolymphatic hydrops depending of hormonal factors; the lack of knowledge about the ethyopatogenic mechanisms in this field generates therapeutic difficulties hard to solve.

Adolescent↗
PubMed1996

[Tympanoplasty in clinical practice: use and results].

The halt in the use of allografts has resulted in the use in clinical practice in humans of a product that has been known for at least thirty years: collagen. Interesting experimental animal studies have been performed with the type I and type III collagen currently used: the Tympanoplast. This collagen, already used in numerous medical fields (digestive, renal and neuro-surgery) is of bovine origin. It is purified, and comes in the form of a reticulated plate. It is known for its qualities of reepithelialisation. We have been using it for more than a year for the reconstruction of the tympanic membrane. We use Tympanoplast 100 microns thick. All the cases of myringoplasties have been performed on dry ears, and essentially on partial perforations in reinforcement surgery. The results are most encouraging and depend on the surgical technique employed. On the other hand, the grafts performed on total perforations failed to produce the expected results. The paper presents work of the School, with the anatomical results and comments on the precautions to be taken when using Tympanoplast.

Audiometry↗
PubMed1996

[Multifrequency impedance audiometry and study of occupational deafness: "Teflag", a new test].

The mechanical acoustic theory compares the annular ligament of the stapes to an elastic plot; plot # 2. The coupled stapedial muscle and annular ligament partly ensure the dampening of acoustic impulses (low frequencies in particular) and helped by the stapes footplate, their transmission, by hydraulic pressure to the liquids of the cochlea. This muscle ligament couple represents the true impedance adaptor for the middle ear region. So as to study plot # 2 we have set up a test, called Teflag, using the otoadmittancemetre produced by Grason Stadler. This apparatus enables us to measure the functional state of the ligament (by the study of susceptance, representing the inverse of the reactive forces linked to the inertial mass of the system and to its compliance; in fact that of the ligament. We can also measure the level of the resistive intra-cochlear forces and those of the annular ligament (the study of conductance). Our study compares 25 normal hearing patients and 64 ears with professional deafness. The Teflag gives us an evaluation of the functional state of the annular ligament, from morphological abnormalities of susceptance. Age induced hearing loss differs from professional deafness. A classification into 5 stages has been established following evaluation of functional annular ligament pathology. There is no hearing without oscillation (of a molecular order) of this ligament, which clearly seems to be the key point of the receptor organ, and ensures the detection of sound.

Acoustic Impedance Tests↗
PubMed1989

[Auditory electrophysiology and retrolabyrinthine non-tumorous diseases]].

The authors present 55 cases of non-tumoral retrocochlear impairment, studied over the period between 1984 and 1988 in the ENT University Clinic of Bordeaux. Deafness was the most frequent symptom leading patients to come for consultation (89%). The stapedial reflex was pathological in 70% of the cases. No conclusion could be drawn from electro-occulography. Only the early auditory evoked responses made it possible to reach the diagnosis of retrocochlear impairment in 35% of the cases. Electrocochleography was required in 65% of the cases to establish the topographic diagnosis. The neuro-radiological examination proved to be negative in 48 cases, and positive in 7 cases (6 atrophic symptoms, 1 left vertebral dolichoartery). Among the other etiologies, we noted 14 cases of auditory trauma, 12 vascular pathologies, 9 neurological pathologies, 7 cases of Ménière's disease, and 7 sudden onsets of deafness. The incidence of vasculo-nervous conflict reported by other authors appears very low in this series (with only 1 case).

Audiometry, Evoked Response↗