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At least 199 records · Page 11Linked to original sources
PubMed1986

Perilymph fistula: the Iowa experience.

Ninety-one patients with demonstrable perilymph fistulas presented with an amazing array of signs and symptoms ranging from unilateral tinnitus and aural fullness to sudden-and-profound hearing loss, roaring tinnitus, and whirling vertigo. Between 1977 and 1984, 214 exploratory tympanotomies for suspected perilymph fistula (PLF) were performed on 177 patients. One hundred six primary (initial) fistulas were found in 95 ears and 26 recurrent fistulas were identified. Eighty-two percent of the 91 patients with PLF had auditory symptoms, 8% with auditory symptoms as the sole complaint. Eighty-one percent of the patients had vestibular symptoms, 12% with vestibular symptoms alone. The type of hearing loss and the nature of the vestibular symptoms were widely variable. Of the 58 patients with preoperative auditory symptoms, 49% had improved hearing (23% improved to serviceable range), after closure of PLFs. Ninety-five percent of the patients who presented with vestibular symptoms had elimination of or decrease in their dizziness to the extent that it no longer interfered with their daily activities. The highest incidence of recurrent fistula was associated with grafts using fatty tissue. Patients with Mondini deformity were at particularly high risk for fistula recurrence.

Adolescent↗
PubMedDate not supplied

Effects of exposure to noise on permeability to potassium of the endolymph-perilymph barrier in guinea pigs.

Healthy guinea pigs were exposed to broadband noise at 115 dBA for 7 days. When perfusion of the scala vestibuli was carried with artificial perilymph containing 43K, the 43K concentrations in the perilymph of the scala tympani were very low in both control and noise-exposed guinea pigs. The transport rate constant for K+ was computed by utilizing compartmental analysis. The results indicate that exposure to noise at 115 dBA for 7 days does not alter the permeability to K+ of Reissner's membrane or the lateral wall of the cochlear duct but does decrease K+ conductance of the organ of Corti.

Action Potentials↗
PubMedDate not supplied

Histopathological study of the cochlea with altered perilymph metabolism.

In 41 guinea pigs an experiment was conducted to determine the effect of kanamycin on ears with or without blockage of the cochlear aqueduct. In 24 animals the cochlear aqueduct was blocked on one side, and after 1 to 21 days, kanamycin (300 mg/kg) was given daily and subcutaneously until the pinna reflex began to decrease. The remaining animals were used for controls: exposure of and trauma to the aperture of the cochlear aqueduct and kanamycin administration (8), blockage of the cochlear aqueduct only (3 plus 17 previous cases), and kanamycin administration to normal animals (6). The survival time of all these animals was four months. The results showed that ears with blockage of the cochlear aqueduct and kanamycin administration consistently demonstrated a more severe and extensive atrophy of the cochlear sensory cells. The lesions occurred primarily at the basal end and spread toward the apical turn, although the lesions in some specimens jumped from the basal to apical turn. The outer hair cells were more extensively affected than the inner hair cells. Proteinaceous precipitates were often found to be slightly greater in the perilymph of cochleae with blocked cochlear aqueducts. From these observations, it is concluded that the decrease in patency of the cochlear aqueduct will impair perilymph metabolism, causing the cochlear sensory cells at the basal turn to become more vulnerable to noxious substances.

Animals↗
PubMedDate not supplied

Effects of experimental renal insufficiency on the osmotic pressure and the biochemical composition of perilymph.

The biochemical effects of experimental renal insufficiency produced by bilateral nephrectomy on perilymph were studied. Rats were used for the experiments; measurements were carried out at various intervals after nephrectomy. Statistically significant changes in perilymph (osmolality, Na, K, Cl, and urea), and serum (osmolality, urea and creatinine) were found. These findings represent a marked labyrinth alteration, and may partly explain the pathophysiology of labyrinthine disturbances in chronic renal disease.

Animals↗
PubMedDate not supplied

Effect of glycerol on pressure difference between perilymph and endolymph.

The pressure difference between the perilymph and the endolymph following administration of 50% glycerol (12 ml/kg) was studied in guinea pigs. The perilymphatic and endolymphatic pressures were measured simultaneously with two sets of a servo-nulling system. Glycerol was administered for about one minute via a gastrocatheter. Both the perilymphatic and endolymphatic pressures began to decrease about 5 min after the administration of glycerol, and thereafter the decrease continued for about one hour with no significant difference between the two pressures. We concluded from the results that the glycerol-induced pressure difference between the perilymph and the endolymph, if present, is only a very small one, although a collapse of the scala media after glycerol intake was reported in guinea pigs and chinchillas.

Animals↗
PubMed1994

Perilymph pressure during hypobaric conditions--cochlear aqueduct obstructed.

Nine cats with the cochlear aqueduct surgically blocked were anaesthetised, put in a pressure chamber, and stepwise exposed to hypobaric pressure, each of the two steps lasting 5 min. The chamber pressure was reduced to -5 and -7 kPa. Concluding the experiment the cats were observed for 5 min after restoration of atmospheric pressure. The perilymph, tympanic cavity, cerebrospinal fluid, central venous, arterial and surrounding chamber pressures were continuously recorded. Reduced chamber pressure caused relative overpressure within the tympanic cavity, thereby inducing pressure gradients between the chamber, the tympanic cavity, the labyrinth and the cerebrospinal fluid and vascular pressures respectively. Our results demonstrate that hypobaric effects on the labyrinth are mediated via pressure changes in the tympanic cavity and not by systemic, vascular or cerebrospinal fluid influence. Substantial perilymph overpressure lasted throughout the hypobaric conditions. The magnitude and the duration of this overpressure were influenced by the patency of the Eustachian tube whereas the rate of the pressure change in the chamber was of little importance. As atmospheric pressure was restored in the chamber the overpressure in the labyrinth was reversed to underpressure--relative to pre-experimental conditions.

Animals↗
PubMed1994

Perilymph fistula: concept, diagnosis and management.

Perilymph fistula is caused by changes of cerebrospinal fluid pressure and/or middle ear pressure. For diagnosis, history taking is extremely important in regard to whether the occurrence of symptoms is related to physical exertion, such as straining, nose blowing, sneezing etc. A variety of symptoms are due to pathologic changes of the membranous labyrinth. Exploratory tympanotomy is needed to verify the occurrence of leakage. However, perilymph fistula cannot be excluded, even if leakage is not observed. Management consists of absolute rest and closure of the fistula. If dizziness or vertigo is intractable and long-lasting, destruction of vestibular function should be considered.

Cerebrospinal Fluid Pressure↗
PubMed1997

[A case report of bilateral perilymph fistula in an adult, with literature review].

Adult bilateral perilymph fistula (PLF) is rare. We report a case of a 55-year-old man who suffered from sudden bilateral hearing loss after blowing his nose. On the first day, he also had bilateral tinnitus but no vertigo. However, he gradually developed vertigo, and nystagmus to the left side began to appear in the following days. Exploratory bilateral tympanotomies were performed and perilymph fistulas were observed at the round window niche in both ears. The round windows were obliterated with fascia of the temporal muscles. After the operation no changes were found in both sides on a pure tone audiogram even at a one-year follow-up. The literature was reviewed and several features were statistically analyzed. In the adult bilateral PLF group, the proportion of the cases in which the cause of PLF was clear was significantly higher than that in the adult unilateral PLF group, but the other clinical features were almost the same. The results suggest that in adults the occurrence of bilateral and unilateral PLF could depend on the level of pressure applied to the middle or inner ear. On the other hand, in the child PLF group, the ratio of bilateral involvement was considerably higher than that in the adult PLF group, and in most cases the PLF was associated with middle and/or inner ear malformations. Healing in the child bilateral PLF group was poor than that in the adult PLF group. Those results suggest that the etiology of bilateral PLF in children may be considerably different from that of adult PLF.

Age Factors↗
PubMed1989

[Influence of otitis media with effusion on perilymph and round window membrane].

To investigate the influence of middle ear effusion (MEE) on perilymph (PL) and the round window membrane (RWM), an experimental otitis media with effusion (OME) was manufactured in chinchillas by injecting the tympanic cavity with immune complexes. The presence of MEE lasted 9 days after the injection of immune complexes. Perilymph was aspirated on the fourth, tenth, 21st, and 60th days after the inoculation. The mean concentrations of albumin, IgG, histamine, and prostaglandin E2 (PGE2) were significantly greater in PL obtained from OME-induced ears than in those from normal control ears. The 3H-PGE2 placed on the RWM of pathologically affected ears passed into PL in significantly greater amounts, compared to normal control ears. The findings of the present study indicate that MEE affect the biochemical milieu of PL.

Animals↗
PubMed1975

Management and prevention of primary perilymph fistula in otosclerosis surgery.

Management of 10 cases of primary perilymph fistula is described. The modified technique of stapedectomy described in this article, seems to prevent primary perilymph fistula; time will tell if it will prevent secondary fistula. The hearing gain obtained with this technique is slightly inferior to the gain obtained with Gelfoam-wire prosthesis, but most significant is the fact that discrimination score is excellent in all cases. The author is convinced that the extra time and dexterity required to perform this procedure are well justified by the safety provided and the results obtained.

Adult↗
PubMedDate not supplied

[Studies of perilymph protein fractions in patients with otosclerosis].

Studies of the blood serum in 20 patients and perilymph in 10 patients with otosclerosis showed stability in concentration of total protein as compared with similar control data obtained from cadavers. In this case proteinograms of the blood serum and perilymph of patients with otosclerosis exhibit a statistically significant decrease in albumin and an increase in globulin fractions mainly at the expense of beta- and gamma-globulins with respect to the control. The data obtained evidence the presence of immunological disorders in patients with otosclerosis.

Adult↗
PubMed2003

Pneumolabyrinth associated with perilymph fistula.

Pneumolabyrinth associated with perilymph fistula, especially with the presence of air in the cochlea, has rarely been identified using imaging study. We present a 24-year-old woman who experienced right fluctuating sensorineural hearing impairment and dis-equilibrium after sustaining an open-handed slap on the right side of her face. The diagnosis of pneumolabyrinth was established through the detection of air bubbles in the right basal turn of cochlea using high-resolution computerized tomography. Right side exploratory tympanotomy confirmed the presence of a perilymph fistula. The patient was free of symptoms after surgery. Early fistula repair was beneficial in this case.

Adult↗
PubMed1992

Effect of round window membrane application of salicylate and indomethacin on hearing and levels of arachidonic acid metabolites in perilymph.

Our previous studies revealed that systemic salicylate-induced ototoxicity is associated with altered levels of arachidonic acid metabolites (AAMs) in the perilymph. In order to eliminate the possibility of systemic toxic effects of salicylate when it is given parenterally, an animal model of salicylate-induced ototoxicity was developed by applying it on the round window membrane (RWM). Using chinchillas as experimental animals, sodium salicylate (150 micrograms) or another nonsteroidal anti-inflammatory drug (NSAID), indomethacin (20 micrograms) was applied on the RWM, cochlear function was determined by auditory brainstem response (ABR) and perilymph assayed for AAMs both prostaglandins (PGs) and leukotrienes (LTs) by high performance liquid chromatography (HPLC) and radioimmunoassay (RIA) at different time intervals. When salicylate or indomethacin was applied on the RWM, dose-dependent ABR threshold losses of 20 to 50 dB was observed in 1 to 2 hours associated with decreased concentrations of 6-keto-PGF1 alpha and elevated levels of LTs. The hearing loss recovered to normal threshold over a period of 8 hours. The control group showed no hearing loss or any change in PG or LT-levels in the prilymph. The results of this study suggest that the method of inducing ototoxicity by applying salicylate or indomethacin on the RWM seems to be a reliable method for avoiding systemic toxicity of the parenteral treatment method and that ototoxicity induced by salicylate or indomethacin may be mediated by decreased PGs and elevated LTs.

Animals↗
PubMed1991

[Effect of gentamicin on the concentration of calcium, magnesium and zinc in perilymph of the guinea pig].

The calcium, magnesium and zinc ions in perilymph of the guinea pig were measured after hearing loss induced by gentamicin. The concentration of the calcium ions and magnesium ions increased, the zinc ions decreased in perilymph. The ototoxicity of gentamicin was related to the changes of these electrolytes in inner ear circumstance. The results showed that the changes of ions were the step of gentamicin ototoxicity.

Animals↗
PubMed1987

Perilymph fistula resulting from microfissures.

Perilymphatic fistulas are well documented in the otolaryngologic literature as a cause for both auditory and vestibular symptoms. The anatomic location of fistulas has been clinically confirmed in both the oval and round windows. Furthermore, membranous tears within the cochlea have been described post mortem and may be the cause of the remaining fistulas which are suspected but not confirmed surgically. A fourth source of perilymph fistula has previously been suggested by Okano and Harada. During the past several years, surgical confirmation of perilymph leakage from two microfissure areas has been observed. These cases will be briefly discussed along with their clinical implications. Speculation as to the type of hearing loss caused by fistulas will be offered. Hypotheses concerning the various symptoms encountered in patients and the location of the defect will also be addressed.

Adult↗
PubMed1986

Role of air bubbles in the perilymph as a cause of sudden deafness.

In the course of exploratory tympanotomies we have several times come across air bubbles leaking with perilymph. The fact prompted the hypothesis that in some cases of perilymphatic fistulas, air bubbles could enter the perilymphatic space from the fistula of the inner ear membrane and cause acute, reversible, profound sensory hearing loss. The experimental study described here was designed to test this hypothesis on guinea pigs. Experiments showed that sudden elevation of middle ear pressure by artificial means caused air bubbles to appear in the scala tympani even at a pressure level of 400 mm H2O. It also proved that air bubbles entered the perilymphatic space through the ruptured round window membrane without damaging Corti's organ or the membranous structure of the cochlea. Sequential recording of the action potential revealed that air bubbles induced acute, reversible, and profound hearing loss of cochlear origin, probably by disturbing the propagation of traveling waves of the perilymph.

Animals↗
PubMed1977

[Determination of the perilymph density in the cochlea of guinea pigs (author's transl)].

The perilymph density of the sc. tympani, sc. vestibuli and the density of liquor cerebrospinalis in guinea-pigs are measured by determination from mass and volume of the fluid column in a glass capillary tube. For the density of perilymph in sc. vest. a value of (formula: see text) in sc. tymp. a value of (formula: see text), and for liquor a value of (formula: see text) was obtained.

Animals↗
PubMed1977

Perilymph penetration of methotrexate in cats.

The perilymph of the inner ear has recently been suggested as a site of frequent leukemic or lymphomatous infiltrates. Experimental evidence supports the existence of barrier mechanisms and explains the attenuated entry of several substances, including chemotherapeutic agents, from either the cerebrospinal fluid or blood into theperilymph. The present study describes the attenuated entry of methotrexate into the perilymph compartment of experimental animals following intrathecal or iv administration.

Animals↗