[Cholesteatoma of the middle ear].
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Aged↗
Biomedical subjects
J Magnan
Publications and source records attributed to J Magnan.
International consensus on middle ear implants.
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Adult↗
[Implication of mitochondrial apoptosis in neural degeneration of cochlea in a murine model for presbycusis].
HYPOTHESIS: Pathologies of senescence, in particular those of neurosensory organs represent an important health problem. The improvement of the life expectation entails the fast increase of the frequency of the presbyacusis in the population. The biological and molecular causes of this degenerative pathology of the inner ear are linked to the disappearance of the sensory cells (inner and outer hair cells) and are associated to nervous damages of the spiral ganglion in the cochlea. We were interested in mechanisms causing the cochlear degeneration in a model of mouse CD 1 presenting prematurely auditive losses. MATERIALS AND METHODS: We tried to correlate the evolution of the hearing and the appearance of apoptotic phenomena by marking with specific antibody, activated anti-caspase-3, in the cochlea during time. We studied the role and the involvement of proteins controlling the apoptosis as the P53 protein and from an energy point of view at the level of the mitochondria such as proteins of the Bcl-2 family and the cytochrome c in the various structures of the cochlea. RESULTS: After implantation of electrodes for auditory nerve acoustic thresholds measurements, the audition of mice CD 1 presented a characteristic profile of hearing losses which begins in the high frequencies from the age of 1 month and which quickly evolves towards the low frequencies. The observation (between the 1st and 3rd month of age) of spiral ganglion cells revealed an unchanged number of cellular bodies of type 1 neurons, on the other hand a characteristic morphology of apoptosis of glial cells with the formation of apoptotic body was noted. Indeed, glial cells expressed activated caspase-3. Furthermore, this phenomenon seems to be under the control of the pro-apoptotic protein Bax by its overexpression and a increased release of the cytochrome c. This phenomenon was followed at 3 and 6 months by the disappearance of the outer hair cells by 9 and 48% respectively. CONCLUSION: The apparition of the deafness in the murin model CD 1 allowed us to demonstrate that the degeneration of cochlear structure begins at the level of glial cells of the spiral ganglion from 3 months, followed thereafter by the deterioration of the nervous conduction between the spiral ganglion and the sensory cells. As a consequence, because of the impoverishment in nervous signals, the outer hair cells would begin to disappear during the 6th month. In conclusion, the understanding of the sequence and the cause of these mechanisms responsible for the neural degeneration and the loss of hearing could eventually, allow us to optimize the various treatments of the presbyacusis.
Adaptor Proteins, Signal Transducing↗
[Are we sectioning the cochlear efferent system during vestibular neurotomy?].
INTRODUCTION: In addition to sensory neurons which transmit information from the inner ear to the brain, there is a system of efferent feedback fibers, called the olivocochlear system, carrying signals from the brain to the ear. Over the past half-century, the efferent system has been extensively studied in animals and results provided theories as to the functional significance of these efferents: to improve signal-to-noise ratio in the auditory periphery, to mediate selective attention, and to protect the inner ear from acoustic overexposure. The results of several studies conducted in man rely on the study of patients who have undergone a vestibular neurectomy. Indeed, anatomical data show that olivocochlear efferents could travel along or inside the vestibular part of the auditory nerve before reaching the organ of Corti. Therefore, these patients may be considered as an experimental model of unilaterally de-efferented subjects. However, to date, none has reported the existence of olivocohlear efferents in the vestibular section following neurectomy. MATERIALS AND RESULTS: In this study, we present the histological results from 18 vestibular sections and show the absence of olivocochlear efferents. CONCLUSION: These results provide a reason to reconsider the results of previous experiments conducted in similar patients and ask for further studies on the olivocochlear efferents pathways.
Cochlea↗
[Trigeminal neuralgia: results of microsurgical and endoscopic-assisted vascular decompression].
INTRODUCTION: Vascular compression of the Vth cranial nerve is the leading cause of trigeminal neuralgia. Microvascular decompression has been promoted by Jannetta since 1970. We used the minimally invasive retrosigmoid approach, with the complementary help of endoscopic procedure. OBJECTIVES: MRI results, surgical findings and pain relief were studied after endoscopic assisted microvascular decompression. MATERIAL AND METHODS: Between 1991 and 2000, 98 surgeries were performed on 79 patients unresponsive to medical treatment, after an average of 6 years from the onset of the disorder. The mean follow-up period after operation was 28 months. RESULTS: MRI predicted neurovascular conflict with sensitivity of 93.6% and specificity of 100%. Pain relief after surgery was complete in 69% of the cases, partial in 21%. Surgery was a failure in 6% of the cases and 4% of patients were lost. Complications were limited to 10% of CSF disorders but only 1% (1 patient) needed a surgical revision. CONCLUSION: Microvascular decompression, performed through a key-hole approach, without cerebellum retraction and with endoscopic assisted surgery, yields a low risk of morbidity, even in elderly patients, and could be considered acceptable causal treatment of trigeminal neuralgia.
Decompression, Surgical↗
Deficits and recovery of head and trunk orientation and stabilization after unilateral vestibular loss.
The aim of the study was to analyse changes in the orientation and stabilization of the head and trunk and their recovery after complete unilateral loss of vestibular information in humans. The ability of nine Ménière's patients to orient and stabilize their heads and trunks in space was investigated during a simple dynamic task of knee-bends and compared with the performance of 10 healthy subjects. Patients' performance was recorded before unilateral vestibular neurotomy (UVN) and during the time-course of recovery (1 week, 1 month, 3 months). Experiments were performed both in eyes open (EO) and eyes closed (EC) conditions to evaluate the role of visual cues in the recovery process. Head and trunk mean angular position (orientation) and mean maximal angular rotation (stabilization) in the roll plane and the yaw plane were recorded using a video motion analysis system. The results indicate that, in the acute stage after UVN (1 week), patients exhibit marked impairments in head and trunk orientation in both visual conditions. In the EC condition, head and trunk were deviated towards the operated side in the roll plane and the yaw plane. Head and trunk stabilization in space was impaired in the roll plane and associated with increased stabilization of the head on the shoulders. Interestingly, vision caused a complete inversion of the orientation pattern, with head and trunk rotations towards the intact side in the roll plane and the yaw plane. Relative to darkness, vision also reduced head and trunk oscillations. Recovery from abnormal head orientation in the light and impaired head stability in both visual conditions was achieved within 1 month and 3 months after UVN, respectively. However, head and trunk orientation in the dark and trunk stabilization in the roll plane remained uncompensated 3 months post-lesion. These results suggest that unilateral vestibular loss leads to a postural syndrome similar to that described previously for various animal species. They confirm the necessity of vestibular inputs for properly stabilizing head and trunk during self-generated displacements in healthy subjects. They also support the notion that vestibular compensation relies on visual cues whose substitution role gradually decreases after UVN.
Adaptation, Physiological↗
Endoscopically assisted minimally invasive microvascular decompression of hemifacial spasm.
OBJECTIVE: The aim of this study was to assess the use of endoscopy in minimally invasive surgery of the cerebellopontine angle in cases of hemifacial spasm. MATERIALS AND METHODS: Eighty patients with hemifacial spasm underwent endoscopically assisted microvascular decompression between October 1992 and October 1998, at the Ear, Nose, and Throat Department of Nord Hospital in Marseille, France. The microvascular decompression was performed via a minimally invasive retrosigmoid approach. The cerebellopontine angle was then explored by a 30-degree endoscope to visualize the root exit zone of the facial nerve and the precise location of the site of the conflict. Microvascular decompression was performed under the microscope. If the site was an artery, a Teflon sponge was inserted; if the site was a vein, it was coagulated and then dissected away from the facial nerve. RESULTS: In 80 patients seen regularly for at least 1 year of follow-up, and including patients operated on once or twice, the procedure was successful in 92.5% of patients, brought about improvement in 3.75% (96.25% success plus improvement), and failed in 3.75%. In relation to the type of conflict, success or improvement was experienced by 90.7% of patients with simple conflicts, 86.2% of patients with multiple conflicts, and 87.5% of patients with nutcracker conflicts. No major postoperative complication or mortality occurred in this series. No facial paresis or paralysis occurred immediately postoperatively. Three patients (3.25%) experienced delayed facial palsy. Postoperative cerebrospinal fluid leak occurred in 2 patients (2.5%) and was treated surgically. CONCLUSION: The principle of minimally invasive surgery in the cerebellopontine angle is gaining universal acceptance. The use of endoscopy in microvascular decompression for hemifacial spasm has helped tremendously in improving the results. In this study, the use of the endoscope enabled the authors to identify the site of the conflict in all cases, and to confirm the position of the Teflon sponge before closure.
Adult↗
Endoscopy as a tool in minimally invasive trigeminal neuralgia surgery.
OBJECTIVE: The aim of this study was assessment of the use of endoscopy in minimally invasive surgery of the cerebellopontine angle in cases of trigeminal neuralgia. METHODS: This study comprises 42 cases of trigeminal neuralgia that underwent operation with endoscopic-assisted microvascular decompression between October 1992 and October 1998. This study was performed in the Ear, Nose, and Throat Department, Nord Hospital, in Marseille, France. The decompression was performed by means of a minimally invasive retrosigmoid approach without a cerebellar retractor. The cerebellopontine angle was then explored by a 30-degree endoscope that gives a panoramic view of this space, with clear visualization of the trigeminal nerve from the pons to Meckel's cave, allowing for the identification of the precise location of the site of the conflict. Microvascular decompression was performed under the microscope by separating the offending vessel from the trigeminal nerve; separation was maintained by the insertion of a piece of Teflon. RESULTS: The site of conflict was detected at the root entry zone of the nerve in 35 patients (83.3%) and at Meckel's cave in 7 patients (16.7%). In 32 cases (76.2%), the type of contact between the vessel and the nerve was of the simple type (1 vessel coming in contact with the nerve in a single point); in 6 cases (14.3%), it was a multiple type (2 vessels touching the nerve in the same point); and in 4 cases (9.5%), it was a nutcracker type (2 vessels compressing the nerve between them). After at least 1-year follow-up and a single operation (cases that required a second operation for revision were considered failures), a successful result was obtained in 31 cases (73.8%), and an improvement was obtained in 4 cases (9.5%). The operation was a failure or early recurrence occurred in 7 cases (16.7%). Postoperative complications were rare. A cerebrospinal fluid leak occurred in only 1 case (2.4%) and was subsequently treated with lumbar puncture and a compressive bandage. CONCLUSION: The minimally invasive retrosigmoid endoscopic-assisted microvascular decompression is an acceptable treatment of primary trigeminal neuralgia. Endoscopy provides a unique way to explore the cerebellopontine angle and to identify the exact location of the neurovascular conflict.
Adult↗
[Adenocarcinoma of the endolymphatic sac in children. A case report].
We report a case of an adenocarcinoma of the endolymphatic sac in a 13 years old child, which was fortuitously discovered at the time of radiological investigation of growth delay. Arising from the end of the endolymphatic sac, this rare tumour shares a similar clinic expression with other cerebellopontine angle pathologies. Radiological investigation reveals a moth eaten appearance to the posterior temporal bone and specific bony inclusions. With MRI there is an intense and/or intermediate signal on T1, a hyper signal on T2 and T1 enhancement with injection of gadolinium. Treatment is surgical and local recurrences are not uncommon. After histological confirmation, a search for Von Hippel-Lindau disease is mandatory because this tumour is not exceptional among this subset of patients. Diagnosis and therapeutic criteria will be highlighted by our case and a review of the literature.
Adenocarcinoma↗
[Bilateral vestibular areflexia: quantification is required].
Bilateral vestibular loss, that should be more precisely qualified as "horizontal semicircular canal bilateral loss", is a concept usually defined by the following characteristics: - no response to caloric tests, - no response to pendular test with a 20-second period, - increasing gain of the cervico-ocular reflex. We present five cases. We increased the stimulation frequency to a level higher than usually, employed and observed that: - at a given frequency threshold a certain amount of reactivity may be observed, - above that threshold the reactivity increases in proportion with stimulation frequency. The apparent vestibular loss is actually related to stimulation frequency. This phenomenon could be explained by considering the physiology of phasic and tonic cells.
Aged↗
How changes in vestibular and visual reference frames combine to modify body orientation in space.
The aim of this study was to analyse how changes in vestibular and visual reference frames combine to modify body orientation in space, and to determine the relationship between postural, oculomotor and perceptive parameters. Changes in vestibular and visual references were investigated by comparing controls and vestibular defective patients (Ménière's patients tested before and one week after unilateral vestibular nerve section) under three visual contexts (light with and without vertical and horizontal coordinates, darkness). Unilateral vestibular loss was responsible for postural and perceptive deviations whose direction depended on the presence of visual reference frame. We suggest these changes vary according to the spatial reference frame patients are based on. Postural changes were related to perceptive modifications but not to eye cyclotorsion.
Adult↗
Cochlear schwannomas.
In a series of 179 cerebellopontine angle (CPA) tumors, the authors present nine cases (5%) that were cochlear nerve neuromas. There were six men and three women (mean age, 51 years). Preoperative magnetic resonance imaging confirmed the diagnosis in one case with a labyrinthine extension and raised suspicions in the other four cases, which were confirmed during surgery. The remaining neuromas were discovered intraoperatively. The mean time between first observation and surgery was 9 months. Preoperatively, all patients underwent a complete otoneurological assessment. The middle fossa approach was used for the patient with the labyrinthine extension, and the retrosigmoid approach was used for the other eight cases. In all patients facial nerve function was preserved. Sudden or major hearing loss without associated vestibular symptoms or preoperative facial paralysis may be predictive of a cochlear component of a CPA tumor. The near-field relationships of cochlear neuromas located at the level of the acoustic and facial nerves can be appreciated because of their small size and strong contrast enhancement.
Journal Article↗
Onset overmasking of a brief amplitude increment in a pure tone and sensorineural hearing impairment.
HYPOTHESIS: The goal of this investigation was to determine, in patients with sensorineural hearing loss who may show an audiologic alteration in onset overmasking, whether different pathologic conditions differ in this respect, and whether patients with a vestibular neurotomy damaging the cochlear efferents will be affected. BACKGROUND: Auditory detection of brief signals, when presented at the beginning of a simultaneous long masking sound, may require a higher acoustic level than when presented after several hundred milliseconds. The proposed explanation, in terms of auditory nerve fibers adaptation has been based on the observation of a proportionally smaller increase of firing in response to an amplitude increment at the onset of a stimulus. However, this may not explain all the data, and other underlying processes are certainly involved. The degree or type of sensorineural pathologic condition may be a contributing factor. In addition, the cochlear efferent system, which exhibits a time course and a high-frequency predominance compatible with that of onset overmasking, could be involved. METHODS: Onset overmasking of a brief amplitude increment in one pure tone was examined in 6 normal subjects, 12 patients who had undergone vestibular neurotomy, 8 subjects with Meniere's-like symptoms, 5 subjects with presbyacusis, and 3 patients with a small neuroma. Both ears of all subjects were tested. Detection thresholds, amount of onset overmasking, and differences between the two ears were examined. RESULTS: All results from subjects with presbyacusis and neuroma were within the range observed in the group of normal subjects. In the group of eight Ménière's syndrome patients, four had results outside the normal range, three had deteriorated detection, and one had better detection. Among the 12 subjects who had undergone neurotomy, 2 had better detection in the unoperated ear. CONCLUSIONS: The results from Ménière's patients indicate that, in addition to the previously reported improved detection threshold for short onset delay, a deterioration of detection thresholds may occur in some subjects. Overall, the results from neurotomized ears do not provide evidence for an involvement of cochlear efferents in this tested psychoacoustic task.
Adaptation, Physiological↗
Clinicopathologic growth factors in vestibular schwannomas: a morphological and immunohistochemical study of 69 tumours.
Tumour growth of vestibular schwannomas is still difficult to predict. The aim of our study was to determine whether any defined histopathological feature was correlated with the clinical course. We did a retrospective study with 69 paraffin-embedded tumours to establish whether the number of vessels, blood cells extravasation or degree of inflammation, all semi-quantitatively assessed, could be indicative of potential of growth. An immunohistochemical study was also performed with an endothelial marker CD34, the leukocyte common antigen CD45 and the estrogen and progesterone hormone receptors. All these parameters were correlated with patient's age, duration of symptoms (d), with a clinical growth index (CLI = tumour size/d). No clinical parameters proved to be predictive of tumour growth. Tumour size was significantly (p = 0.01) related to the number of vessels and we found a significant relationship between the clinical growth index (CLI) and total number of vessels, especially when duration of symptoms lasted less than 1 year (p < 0.001). However, we found no relationship between duration of symptoms or CLI and CD34 index. The degree of inflammation was significantly correlated (p = 0.007) with duration of symptoms when it lasted more than 1 year. The CD45 index and the semi-quantitative evaluation of the inflammation were well correlated (p = 0.001). No estrogen receptors antigenic site was detected and only seven tumours expressed progesterone receptor in a few cells without any significant clinical value. These results suggest that vessel density is determinant for sporadic acoustic neuroma growth especially for a short clinical course.
Adult↗
[Our current results with acoustic neurinoma surgery].
Out of 130 CPA tumors operated on between 1993 and 1997, 91 were vestibular schwannomas less than 25 mm with preoperative hearing and normal facial function. The pre and postoperative facial and hearing functions were analyzed prospectively. The surgical technique applied was the complete tumor removal via retrosigmoid approach under facial nerve monitoring and CPA endoscopy. Clinical features were analyzed to determine postoperative facial grading (House-Brackmannn) and tonal and vocal audiometrical datas (PTA-SDS) at 8 days, 90 days and 1 year. We achieved 96 % of good facial results (Grade I and II/HB) and 46,5 % of postoperative conserved hearing. For tumors less than 25 mm in the CPA, good preoperative hearing level, preoperative AOE and BER seem to be predictive factors for hearing preservation. Early diagnosis associated with the advances in minimal invasive otoneurological techniques leads to perform complete removal of this type of tumors with respect of facial and hearing functions.
Adult↗
Spatial performance of unilateral vestibular defective patients in nonvisual versus visual navigation.
The purpose of this study was to investigate the effects of unilateral vestibular neurotomy on humans ability to perform navigation tasks. These tasks provided self-motion feedback by way of either locomotor activity only (nonvisual navigation or "locomotor task") or visual motion cues only (visually simulated navigation or "visual task"). After exploration of an environment in which 4 locations were marked by different objects, subjects attempted to navigate to those locations either by reproducing the same paths as those followed during exploration, by reversing routes, or by making spatial inferences (shortcuts). Vestibular defective patients were tested one day before surgical treatment and during the recovery time course following unilateral vestibular nerve lesion (1 week, 1 month, and 3 month later). Their performance was assessed by measuring turn error and distance error in both navigation tasks and was compared to that of control subjects tested 4 times at similar time intervals. Turn error in the reproduction of previously explored routes in the locomotor task was lower in patients before surgery than in controls, suggesting the existence of compensatory processes. In the acute stage (1 week) after unilateral vestibular lesion, turn error was greater in patients than in controls for the highest level of mental representation (spatial inferences or reversing routes); impairment at making accurate rotations had disappeared by 1 month after vestibular lesion in both navigation tasks. These results point to the role of vestibular cues, in interaction with other sensory modalities, in the elaboration of an accurate internal representation of the environment. In addition, they suggest that unilateral suppression of vestibular information would induce transitory spatial memory disorganization at a high level of information processing.
Distance Perception↗
Idiopathic temporal encephalocele: report of two cases.
BACKGROUND: Idiopathic brain herniation into the middle ear is a rare condition that represents diagnostic and therapeutic challenges. OBJECTIVE: The authors present here two new cases of idiopathic brain herniation with special clinical presentation and emphasis on radiographic studies, particularly computed tomographic scan and magnetic resonance imaging, which allowed the authors to detect the malformation. RESULTS: The two patients underwent surgical treatment with infratemporal approach and recovered perfectly.
Diagnosis, Differential↗