F. Portier

Spontaneous Intracranial Hypotension: A Rare Cause of Labyrinthine Hydrops

Spontaneous intracranial hypotension should be considered as a possible cause of cochlear hydrops. We report a case of unilateral hearing loss attributed to spontaneous intracranial hypotension on the basis of characteristic abnormalities seen on magnetic resonance imaging. The diagnostic gold standards for intracranial hypotension are lumbar measurement of cerebrospinal fluid pressure and magnetic resonance imaging. The usual treatment is an autologous blood injection into the peridural spaces. The mechanism of hearing loss is thought to involve secondary perilymph depression due to a patent cochlear aqueduct. This perilymph depression would induce a compensatory expansion of the endolymphatic compartment, with a subsequent decrease in basilar or Reissners membrane compliance. Endolymphatic hydrops can occur in the course of intracranial hypotension, and not only because of abnormal endolymph production or resorption. Hydrops can thus be classified into 1) syndromes of endolymphatic origin and 2) syndromes of perilymphatic origin, in which loss of perilymph induces compensatory expansion of the endolymphatic space.

Transnasal endoscopic removal of an orbital cavernoma

The approach to posterior and medial orbital tumors is still a challenge, since poor functional results are frequent. We report a case of cavernoma successfully removed by a modified transnasal endoscopic procedure. The patient, a 56-year-old woman, complained of a decrease in vision of the left eye. Magnetic resonance imaging evidenced a lesion in the posterior part of the orbital cavity, inferior to the optic nerve, extending to the sphenoidal cleft. The lesion was isodense on T1-weighted images and showed contrast enhancement. Because of the medial location of the tumor, the patient was referred to the otolaryngology department by the neurosurgeons, and a transnasal endoscopic approach was chosen. A large exposure of the operative field was obtained, and a cavernoma was removed. Rapid relief of the symptoms was obtained. In view of this good result, we advocate the transnasal endoscopic approach in cases of inferomedial and posterior intraconal lesions as an alternative and addition to the standard techniques of orbital surgery.

Experimental model for investigating trans-mucosal gas exchanges in the middle ear of the rat

Objective The total pressure in the middle ear depends on the air composition of this gas pocket, i.e. on gas exchanges occurring through either the Eustachian tube (ET) or mucosa. The aim of this study was to develop an experimental model to investigate the exclusive role of trans-mucosal gas exchanges in the middle ear (ME). Material and Methods Both tympanic membranes of 20 Sprague–Dawley rats were punctured under general anesthesia. Rats were divided into two equal groups. Group 1 had no ET obstruction. In Group 2, the ET was blocked, after velar incision, by cauterization and application of cyanoacrylate glue into the lumen. One open transparent glass tube containing a droplet of colored water was placed horizontally and connected hermetically to each ear canal. The ME was then flushed with room air through the tube. Variations in ME gas volume were measured by reading the displacement of the liquid droplet in the horizontal tube. The kinetics of variations in gas volume between groups were displayed and statistically compared using a two-sided t-test. Results The pattern of variations in ME gas volume with time was similar in the two groups. Both were characterized by a decrease with three phases and an elimination rate of ≈0.152±0.026 μl/min. There was no significant difference in the mean rate of ME volume changes between the two groups. Conclusion This experimental model allows investigation of trans-mucosal gas exchanges. These exchanges exhibit an absorptive function resulting in a negative pressure that must be compensated, under physiological conditions, by air flow through the ET.

Oxygen modulates Na+absorption in middle ear epithelium

The physiology of the middle ear is primarily concerned with keeping the cavities air filled and fluid free to allow transmission of the sound vibrations from the eardrum to the inner ear. Middle ear epithelial cells are thought to play a key role in this process, since they actively transport Na+ and water. The PO2 of the middle ear cavities varies from 44 to 54 mmHg in healthy human ears but may be lower in the course of secretory otitis media. The effect of chronic hypoxia on ion transport was investigated on a middle ear cell line using the short-circuit current technique. Chronic hypoxia reversibly decreased the rate of Na+ absorption across the MESV cell line. Although a decrease in cellular ATP content was observed, the decrease of Na+ absorption seemed related to a primary modulation of apical Na+ entry. As revealed by RNase protection assay, the decrease in the rate of apical Na+ entry strictly paralleled the decrease in the expression of transcripts encoding the alpha-subunit of the epithelial Na+ channel. This effect of oxygen on Na+ absorption might account for 1) the presence of fluid in the middle ear in the course of secretory otitis media and 2) the beneficial effect of the ventilation tube in treating otitis media that allows the PO2 to rise and restores the fluid clearance.The physiology of the middle ear is primarily concerned with keeping the cavities air filled and fluid free to allow transmission of the sound vibrations from the eardrum to the inner ear. Middle ear epithelial cells are thought to play a key role in this process, since they actively transport Na+ and water. The [Formula: see text] of the middle ear cavities varies from 44 to 54 mmHg in healthy human ears but may be lower in the course of secretory otitis media. The effect of chronic hypoxia on ion transport was investigated on a middle ear cell line using the short-circuit current technique. Chronic hypoxia reversibly decreased the rate of Na+absorption across the MESV cell line. Although a decrease in cellular ATP content was observed, the decrease of Na+ absorption seemed related to a primary modulation of apical Na+entry. As revealed by RNase protection assay, the decrease in the rate of apical Na+ entry strictly paralleled the decrease in the expression of transcripts encoding the α-subunit of the epithelial Na+channel. This effect of oxygen on Na+ absorption might account for 1) the presence of fluid in the middle ear in the course of secretory otitis media and 2) the beneficial effect of the ventilation tube in treating otitis media that allows the[Formula: see text] to rise and restores the fluid clearance.

Aneurysmal bone cyst in the sphenoid bone : Treatment with minimally invasive surgery

Aneurysmal bone cysts are vascular lesions that destroy and expand bone. We report a recently treated case of an aneurysmal cyst of the sphenoid bone. A 14-year-old girl presented with frontal headaches, bouts of nausea, and vomiting. Computed tomography and magnetic resonance imaging showed typical features of an aneurysmal bone cyst. Arterial embolization was undertaken before surgery. The endoscopic transnasal procedure used allowed the complete removal of the aneurysmal bone cyst. This use of minimally invasive surgery makes this case of interest to surgeons of the skull base and sinuses.

Cochlear electrical stimulation: Influence of age of implantation on Fos immunocytochemical reactions in inferior colliculi and dorsal cochlear nuclei of the rat

The influence of age at the time of implantation of a stimulating electrode unilaterally in the inner ear on central auditory pathways was investigated in rats deafened shortly after birth. Immunoreactivity for Fos served as a functional marker of neuronal activity. Electrodes were implanted in the left cochlea of rats aged 3 weeks or 4 months. Stimulation lasted 45 minutes, then rats were sacrificed and tissues processed for immunocytochemistry. The younger animals showed significantly more neurons with Fos immunoreactivity bilaterally in the dorsal cochlear nuclei (DCN) and inferior colliculi (IC) than the older rats or control animals with normal hearing receiving the same stimulation. Activity was more prominent in the left DCN and right IC. The results show that electrical stimulation of the inner ear is more effective in younger animals in eliciting gene expression associated with development of a functional network in the auditory pathways. This suggests that deaf children should be provided with cochlear implants as early as possible. J. Comp. Neurol. 438:226–238, 2001.

Prise en charge des fistules labyrinthiques cholestéatomateuses : A propos de 22 cas

Objective: To study the incidence, location, pre- and postoperative symptoms (hearing loss, tinnitus, vertigo, facial palsy), preoperative diagnostic imaging, and surgical treatment of labyrinthine fistulae (LF). Design: Retrospective case review. Patients: Twenty-two cases of LF over 382 mastoid operations performed in a 168-month period. Main Outcome Measures: Clinical, imaging, and surgical correlation of extensive fistulae and bone fistulae. Results: LF prevalence was 5.8%. The main primary symptoms were otorrhea and hypoacusis. Only four patients presented vertigo as their main complaint. All patients underwent preoperative computed tomographic (CT) scans and preoperative audiometry. LF diagnosis was made before surgery for 100% of patients on the basis of CT scan. A second fistula was, however, misdiagnosed by imaging in two patients. With respect to surgical technique, a canal wall down procedure was performed in 77% and a conservative procedure was performed in 23%. Fistula was located in the horizontal semicircular canal in 100% of cases, and in 9%, a second fistula was operatively diagnosed. In 91% of cases, the matrix was removed, whereas it was left in the course of a canal down procedure in 9%. With a follow-up of 5.7 years, hearing remained unchanged in 80% of patients. Conclusions: Surgery with removal of the cholesteatoma matrix and sealing of the fistula with temporalis fascia is a safe procedure that can help preserve cochlear function. The choice of a canal down procedure would be influenced by cholesteatoma characteristics rather than by the finding of an LF.

Carcinome épidermoïde sur kyste du tractus thyréogosse

Objectif Les auteurs presentent un cas de carcinome epidermoide developpe sur un kyste du tractus thyreoglosse chez une adulte. Les modalites de prise en charge et la necessite d’une prevention sont discutees. Patient et methode Patiente de cinquante-cinq ans suivie pour un kyste du tractus thyreoglosse en raison d’un refus parental d’une chirurgie au cours de l’enfance. Resultats Le diagnostic a ete evoque sur une augmentation de volume et des douleurs cervicales. En raison d’un envahissement carotidien et de l’axe larynge, le traitement radiochirurgical n’a pas permis de guerison bien que l’evolution locale soit controlee par une chimiotherapie palliative avec deux ans de recul. Discussion L’exerese dans l’enfance des kystes du tractus thyreoglosse (KTT) est davantage pratiquee afin de prevenir des poussees infectieuses qu’une transformation maligne. Bien que faible, le risque de developpement d’un carcinome sur kyste du tractus thyreoglosse est certainement sous-evalue en raison d’une chirurgie d’exerese preventive tres souvent realisee dans l’enfance. Conclusion L’evolution dramatique du cas presente nous amene a recommander encore une fois une chirurgie d’exerese preventive de ce type de malformation, et a discuter les modalites de prise en charge de ce type d’evolution.

Enhanced sodium absorption in middle ear epithelial cells cultured at air–liquid interface

Conclusion As we demonstrated previously that transcription of α-ENaC was correlated with oxygen tension in the culture medium, this study suggests that the increase in α-ENaC expression observed under ALI conditions may result from greater oxygenation of ME cells. Objective The physiology of the middle ear (ME) is primarily concerned with keeping the cavities fluid-free, to allow transmission of sound vibrations from the eardrum to the inner ear. ME epithelial cells are thought to play a key role in this process as they actively absorb sodium and water in order to clear any excess fluid present in the cavities. Material and methods As an air–liquid interface (ALI) model has been shown to improve differentiation and enhance sodium absorption in other respiratory epithelia, we established an ALI model for ME cells. Results ME cells cultured under ALI conditions exhibited a fourfold increase in sodium absorption, which was not related to either a metabolic effect or to enhanced morphological differentiation, but instead to an increase in expression of the α-subunit of the epithelial sodium channel (α-ENaC).

Serous or mucoid effusion in the course of secretory otitis media: influence of ion transport modulation.

OBJECTIVE Secretory otitis media is defined by a chronic effusion in the middle ear cavities, behind an intact tympanic membrane without acute infection. In the course of secretory otitis media, the effusion is sometimes thick (or mucoid) and other times thin (or serous). For several authors, these differences might be related to different inflammatory levels rather than to distinct pathophysiological mechanisms. The purpose of this study was to determine whether the modulation of ion transport by inflammation could account for the differences observed in the aspect of ME effusion. METHODS Hydrogen peroxide (H2O2), used as an inflammation model was tested on a middle ear cell line (MESV) in culture. RESULTS Results show that low and high concentrations of H2O2 have opposite effects on ion (and then water) absorption by the middle ear epithelium. CONCLUSION the modulation of ion and water absorption by inflammation could modify the mucins concentration in the effusion, and explain observed viscosity differences in the course of secretory otitis media.