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PubMed1977

Round window ultrasonic treatment of Meniere disease.

The neurosensory structures within the vestibular labyrinth of the inner ear are selectively irradiated with ultrasonic energy to alleviate the vertiginous symptoms of Meniere disease. However, correct application and coupling of the ultrasonic transducer to the inner ear is essential for maximum transmission of energy into the vestibule. The importance of assessing the results of long-term postoperative treatment is demonstrated by a change in the success rate that decreased by approximately 10% when the results obtained within the first 12 months of treatment were compared with those after four years. In this investigation, 32 patients were treated by the round window approach between 1970 and 1972, and after four years it was found that 72% of these were successful in relieving the giddiness symptoms.

Evaluation Studies as Topic↗
PubMedDate not supplied

Adenovirus-mediated expression of brain-derived neurotrophic factor protects spiral ganglion neurons from ototoxic damage.

Hair cell loss, the most common cause of deafness, is often associated with auditory nerve degeneration. Our goal was to determine the influence of combined ciliary-derived neurotrophic factor (CNTF) and brain-derived neurotrophic factor (BDNF) gene therapy on the survival of spiral ganglion neurons (SGNs) after elimination of inner hair cells in the mature guinea pig ear. Seven days after bilateral deafening, a 5-microl suspension of CNTF and/or BDNF adenovirus vectors was injected into the left scala tympani through the round window. Animals were sacrificed 28 days after deafening, and their inner ears were prepared for SGN counts. The SGN counts revealed that BDNF alone and the combined CNTF and BDNF treatment significantly enhanced SGN survival. CNTF did not significantly enhance the protective effect of BDNF. These data present possible strategies for enhancing SGN survival in cochlear implant procedures.

Adenoviridae↗
PubMed2003

Exploratory tympanotomy: an integral part of cochlear implantation.

We report on 113 multichannel intracochlear implantations. Although the surgical approach has evolved as a result of new implant designs, one essential step has remained, namely initial exploratory tympanotomy. This 15-min procedure allows direct anatomical assessment and work in the middle ear. After direct exposure, the lip of the niche is removed and the round window membrane is visualized. The basal turn of the cochlea is then assessed for patency, and the capability of inserting electrodes is verified. The surgical procedure is then performed in the knowledge that an adequate insertion will be possible. This approach allows insertion through the round window instead of a cochleostomy hole, thus avoiding potential damage to remaining neural structures and additional exposure of inner ear structures and electrodes to potential middle ear infections. It also requires a limited mastoidectomy (extended antrotomy) as the facial recess is visualized from the middle ear side (avoiding the need for extensive drilling), and the mastoid and facial recess openings are only used as conduits for the electrode array. In this study, 14/113 patients (12.4%) had either different degrees of ossification (n = 11) or Mondini deformity (n = 3). Direct work in the middle ear allowed handling and drilling as required in all cases. In two cases with severe ossification, a cochlea was sculpted around the modiolus. This included drilling of the anterior portion, which is inaccessible using the facial recess approach.

Cochlear Implantation↗
PubMed2006

The size of the cochlea and predictions of insertion depth angles for cochlear implant electrodes.

AIMS: To establish normative data on the size of the basal turn of the cochlea using high-resolution computed tomography of the temporal bone in adults and children. To determine whether final insertion depth angle for a perimodiolar cochlear implant electrode varies according to cochlear size. METHODS: Forty-two patients screened for cochlear anomaly using computed tomography were randomly selected from patients with otologic disease. Reconstruction of the full basal turn was performed for both ears using a 1.0-mm layer, minimum intensity projection. The largest distance from the round window to the lateral wall (distance A) and the perpendicular distance (B) were measured. Distances were averaged between ears for each individual. In addition, 15 patients were implanted with the Nucleus 24 Contour Advance electrode array using a linear insertion depth of either 17 mm (n = 9) or 19 mm (n = 6). Postoperative X-rays were analyzed using the method of Xu et al. [Am J Otol 2000;21:49-56] to obtain the insertion depth angles for individual electrodes. RESULTS: Mean distance A was 9.23 mm (SD = 0.53, range 7.9-10.8 mm). Perpendicular distance B was significantly correlated with distance A (r2 = 0.57, p < 0.001). The mean difference in insertion depth angle between the 17 and 19 mm groups was 80 degrees . A statistically significant correlation (r2 = 0.51) was found between distance A and the insertion depth angle for the 17 mm group. CONCLUSIONS: The cochlear size measure distance A was repeatable to within the resolution of the high-resolution computed tomography image data. The basal turn of the normally formed cochlea is variable in size. These variations in size would produce >5.0 mm variation in the length of the lateral wall to the point consistent with an insertion depth angle of 360 degrees . Cochlear size influenced final insertion depth angles obtained for the perimodiolar Nucleus 24 Contour Advance electrode.

Adolescent↗
PubMed1994

Transdermal scopolamine for the reduction of postoperative nausea in outpatient ear surgery: a double-blind, randomized study.

We evaluated the effect of transdermal scopolamine on the incidence of postoperative nausea and vertigo after outpatient ear surgery (exploratory tympanotomy, mastoidectomy, or endolymphatic sac and oval and round window surgery) in a double-blind, placebo-controlled study. A transdermal patch containing either scopolamine (n = 19) or placebo (n = 20) was placed behind the nonsurgical ear 2 h before surgery. Anesthesia was induced with thiopental (4-6 mg/kg intravenously [i.v.]), sufentanil (0.5 microgram/kg i.v.), and vecuronium (0.1 mg/kg i.v.) and maintained with isoflurane (0.2%-2%) and nitrous oxide (70%) in oxygen. Patients were observed postoperatively in the recovery room and after discharge for 72 h. There was no significant difference between groups with respect to time in recovery room, time to discharge, incidence of in-house nausea, vomiting, amount of antiemetics required, or postoperative visual analog scale (VAS) scores while in the hospital. After discharge, there were lower VAS nausea scores (by repeat measures analysis, P < 0.05) and a lower reported incidence of nausea (31% vs 62%; P < 0.05) and vertigo (6.2% vs 25%; P < 0.05) in the active patch group versus the placebo group. There was a higher incidence of dry mouth in the active patch group (44% vs 25%). Seven patients did not complete the study due to failure to keep the patch in place or failure to return the diary from home; and one patient from the placebo patch group was admitted for uncontrolled nausea and vomiting. The authors concluded that transdermal scopolamine is effective in reducing, but not eliminating, postoperative nausea and vertigo after discharge in outpatient ear surgery.

Administration, Cutaneous↗
PubMedDate not supplied

Polytomography and congenital anomalies of the ear.

Conventional radiography and even high resolution computerized axial tomography leave much to be desired in demonstrating the minutiae of the anatomy of the temporal bone. Multidirectional tomography remains the examination of choice radiographically in cases of congenital anomalies of the temporal bone. Details of the inner, middle and even external ear in the presence of atresia are more clearly delineated by this method than any other to data. Such information is of inestimable value to the surgeon in the diagnosis and surgical correction of anomalies of the temporal bone. Important features of the vestibule, semicircular canals, cochlea, facial nerve, internal auditory canal, temporomandibular joint, pneumatization of the temporal bone, tegmen, tympanic cavity, ossicles, oval and round windows, jugular bulb and carotid artery and the external ear canal are discerned most clearly by multidirectional tomography.

Ear↗
PubMed1994

Occupational perilymph fistula.

A case of occupational perilymph fistula in an ironworker is described. The patient was lifting and lowering 200 pounds of steel when he developed sudden onset of vertigo. Surgical exploration of the middle ear demonstrated leakage of perilymph fluid from the round window. Grafting of the window led to improvement of symptoms, but the patient was unable to continue work as an ironworker due to difficulty with balance.

Adult↗
PubMed1989

Ototoxicity of antimycotics.

Neither otomycoses nor defects of the tympanic membrane are rare. In cases of fungal infection when the tympanic membrane is not intact, the possibility exists that antimycotic medication could enter the middle ear and diffuse into the cochlea via the round window. Five antimycotic preparations were tested for acute ototoxic potential in guinea pigs. Those containing acetic acid or propylene glycol caused appreciable elevation of brainstem response thresholds, while little or no impairment resulted from tolnaftate or clotrimazole solutions in polyethylene glycol 400.

Animals↗
PubMed1981

Inner ear hearing loss in acute and chronic otitis media.

Temporary or permanent threshold shift of bone conduction occurs frequently in acute or chronic otitis media. The sensorineural hearing loss is dependent on the age of the patient and the duration of the illness. Fluid in the middle ear may impede sound transmission and oxygen transport to the inner ear. In middle ear inflammation noxious substances may pass across the round window membrane leading to serous labyrinthitis. In therapy ototoxic drugs and operations (tympanoplasty) can cause sensorineural deafness.

Acute Disease↗
PubMed1975

[Experimental changes of the pH in the middle ear and its effect on the internal ear (author's transl)].

Irrespective of their highly differing pH-value many pharmaca are nowadays applied to the middle ear. Animal experiments are to answer the question, weather changes in the pH-value of the middle ear may cause internal ear damages, With local application of different buffers (2.3-9.1 pH) into the tympanic cavity, the membrane of the round window was examined by means of the surface preparation technique, the pH-value of the perilymph was measured and the hair cells of the organ of corti were counted and histologically evaluated. With the reduction of the pH-value in the middle ear from 4.0 to 2.3 an increasing damage of the round window membrane could be detected. The pH-value of the perilymph, however, showed only a slight statistical variation, which cannot be guaranteed. After multiple applications of extremely acid buffers into the tympanic cavity directly before the round window membrane, a small but statistically significant reduction in the pH-value of the perilymph could be noticed. Hair cell damages at the organ of corti could in no case be observed.

Administration, Topical↗
PubMedDate not supplied

Ototoxicity of topically applied gentamicin using a statistical analysis of electrophysiological measurement.

Ototoxicity of topically applied gentamicin was studied in guinea pigs. 0.3% gentamicin was instilled in one side of the middle ear cavity and Ringer's solution was instilled in the other side, and the difference in the cochlear microphonics measured with the round window electrode was analysed statistically. Instillation of Ringer's solution in the middle ear cavity for 1 day did not cause any significant sensorineural hearing loss, but on the 3rd day of instillation significantly reduced responses were observed, compared with the responses from non-treated ears, followed by a partial recovery starting on the 4th day. When gentamicin 0.3% was instilled into the middle ear cavity, significant deafness occurred 24 hours later, and highly significant deafness on the 2nd and 3rd day. The usage of gentamicin ear drops of the current formula should be discouraged until a better formula is provided.

Acoustic Stimulation↗
PubMed2003

Congenital aplasia of the semicircular canals.

OBJECTIVE: To describe the underrecognized inner ear malformation characterized by complete aplasia of the labyrinthine semicircular canals associated with a relatively well-formed cochlea, to investigate its relationship with known syndromic forms of hearing loss, and to hypothesize regarding the potential embryopathogenesis of this anomaly. STUDY DESIGN: A retrospective case review consisting of cases of sensorineural hearing loss with radiographic evidence demonstrating agenesis of the semicircular canals associated with a cochlea that was either morphologically normal or sufficiently well developed to accommodate the full insertion of a cochlear implant electrode. Cases were identified by computerized tomography findings that identified the anomaly under study. SETTING: Departments of otolaryngology and radiology in a tertiary referral center, with a large cochlear implant program serving over 800 patients, more than half of whom are children. PATIENTS: Fifteen patients with the anomaly under study were identified. INTERVENTIONS: Each patient underwent a complete otologic examination, audiometric studies, and high resolution computerized tomography of the temporal bone in axial and coronal planes. MAIN OUTCOME MEASURES: The bony morphology of the cochlea, round and oval windows, vestibule, semicircular canals, and vestibular aqueduct, and the course of the facial nerve were examined. Auditory findings and otologic treatment are presented. RESULTS: Of the 15 identified patients, 4 were nonsyndromic, 9 had CHARGE association (Coloboma of the eye, congenital Heart defects, choanal Atresia, mental and/or growth Retardation, Genital hypoplasia, and Ear anomalies and/or deafness), 1 met criteria for Noonan's syndrome, and one had features of both these syndromes. Although the cochlea was present in all cases, the cochlear morphology was usually abnormal in the CHARGE association patients. Of the 20 ears in the CHARGE subjects, only 3 ears (15%) were seen to have completely normal development of the cochlea in both the basal and upper turns. The others showed either mild hypoplasia of the upper turns (13 ears, 65%) or an incomplete partition typical of the classic Mondini deformity (4 ears, 20%). In the 4 nonsyndromic cases, one subject had bilateral Mondini dysplasia and the other three had normal cochleae. In the entire group, abnormalities of oval window development were common (20 of 30 ears, 67%), especially in the syndromic cases (18/22, 81%), but the round window was normal in the majority of cases (73%). Seven patients in the CHARGE association group had an anomalous course of the facial nerve, which was particularly severe in three. Four patients had congenital unilateral facial paralysis, although two of these children had normal radiographic anatomy of the facial nerve. One patient had bilateral facial weakness. CONCLUSIONS: Syndromic and nonsyndromic cases of isolated semicircular canal aplasia were identified. Except for mild to moderate cochlear dysplasia, and the anomalous course of the facial nerve in some CHARGE association patients, both groups of patients were generally suitable for cochlear implantation if indicated. A high incidence of oval window aplasia with normal round window development may help to explain the embryopathogenesis of this anomaly, considering the sequence of inner ear development.

Abnormalities, Multiple↗
PubMed2003

Distribution of gentamicin in the guinea pig inner ear after local or systemic application.

Uptake and retention of gentamicin by cells in the guinea pig inner ear after a single peritoneal injection or local application on the round window were investigated using immunocytochemistry to localize the drug. The cells that accumulated the drug under the two conditions were the same, but staining for the drug was more intense and was often accompanied by widespread cochlear degeneration following local application. Soon after drug administration by either route, there was diffuse staining for the drug throughout all tissue within the labyrinth, including bone. At later times when distinct cell staining became evident, virtually all cell types were found to be positive, with several cell types staining more darkly for the drug than hair cells, indicating that hair cells were not the most avid in accumulating gentamicin. The infracuticular portion of auditory and vestibular hair cells as well as type III fibrocytes of the spiral ligament were positively stained in almost all cases and these sites were found to be positive for as long as six months post administration. In animals with loss of the organ of Corti, there was unusually intense staining for gentamicin in root cells of the spiral ligament, in marginal cells of the stria vascularis, and in cells of the spiral limbus. Dark staining of surviving cells in cases with overt tissue destruction suggests that variability in the extent of damage caused by the drug was determined more by the degree of its local uptake than by differences in animals' capacities to metabolize the drug systemically. The present results show that gentamicin may damage or destroy all cochlear cells following a single round window application. The findings broaden the scope of our knowledge of cochlear gentamicin uptake and damage and have implications for treatment of patients with vestibular disorders by infusion of aminoglycosides into the middle ear, as well as implications for prospects of rehabilitating patients that have been deafened by aminoglycosides.

Administration, Topical↗
PubMed1993

Distortion in the cochlea: acoustic f2-f1 at low stimulus levels.

The stimulus level and frequency dependence of the quadratic difference tone (QDT) measured as an otoacoustic emission in the ear canal has been investigated in the guinea pig and compared with simultaneously measured cubic difference tone (CDT) and with the round window electrical response. Acoustic QDT level tended to be highly labile. Growth of the ear canal response with covaried stimuli was very gradual (slope < 0.5). Acoustic and CM responses showed similar behaviour when f2 alone was incremented. The QDT was strongly dependent on stimulus frequency separation for high frequency stimuli. It is suggested that, at low stimulus levels and high frequencies, the acoustic QDT may originate in the 'tonic' motile responses of outer hair cells as they follow the envelope of the two-tone stimulus.

Acoustic Stimulation↗
PubMed2004

Cochlear implantation in children with otitis media: second stage of a long-term prospective study.

OBJECTIVE: To present the findings of the second stage of an ongoing prospective study of the outcome of cochlear implantation in otitis media (OM)-prone and non-OM-prone children who were treated according to a structured protocol designed to control OM prior to implantation. PATIENTS AND METHODS: Of 60 children referred for cochlear implantation during the study period, 34 were classified as OM-prone (Group A) and 26 as non-OM-prone (group B). Group A patients were managed according to a structured protocol aimed at pre-implantation control of OM. A ventilating tube (with or without adenoidectomy) was inserted in the affected ear(s) of these children, if necessary more than once. Post-implantation follow-up ranged from 3 to 45 months (average 20 months). RESULTS: In the OM-prone group of children, the mean age at referral and at implantation was significantly lower and the mean interval between referral and implantation significantly higher than in the healthy group. During implantation, 21 children (19 from the OM-prone group A) had thick middle ear mucosa that had to be removed to allow identification of the round window niche. After implantation, 13 of the OM-prone children (38%) and 2 of the non-OM-prone children (7.6%) developed acute OM in the implanted ear. Five of these cases, all belonging to the OM-prone group, proved to be recurrent and therapeutically challenging, and 2 of them also developed acute mastoiditis. There were no other OM-related complications. CONCLUSIONS: Early referral led to early implantation, even in children susceptible to OM. The incidence of OM decreased after implantation, but was still significantly higher in the OM-prone group. On the basis of these results, we recommend the continuous use of a ventilating tube in OM-prone pediatric implantees until they outgrow their susceptibility to OM.

Child↗
PubMed2005

Otic barotrauma from air travel.

Otic barotrauma occurring during air travel involves traumatic inflammation of the middle ear, caused by a pressure difference between the air in the middle ear and the external atmosphere, developing after ascent or more usually descent. The pressure difference occurs because of failure of the eustachian tube to equilibrate middle ear and atmospheric pressures. It is a common problem, presenting with ear fullness, otalgia and deafness. Severe cases may result in tympanic membrane perforation and even round window membrane rupture. Of three randomized controlled trials, one showed that oral pseudoephedrine decongestants reduced otalgia in adults with recurrent ear pain during air travel, whilst another found that oral pseudoephedrine did not decrease in-flight ear pain in children. The third trial showed that oxymetazoline decongestant nasal spray, taken 30 minutes before descent, did not produce a statistically significant reduction in symptoms of barotrauma in adults with recurrent ear pain during air travel. We review the causes, prevention and treatment of this condition.

Adult↗
PubMed1992

Effect of exogenous arachidonic acid metabolites applied on round window membrane on hearing and their levels in the perilymph.

Our previous studies revealed that treatment with sodium salicylate or indomethacin caused hearing loss, a decrease in prostaglandin (PG) levels, and an increase in leukotriene (LT) levels of the arachidonic acid (AA) cascade in the perilymph. We suspected that decreased PG-levels and/or elevated LT-levels in the inner ear may be responsible for the salicylate ototoxicity. In order to test this hypothesis, effects of exogenous treatments with PGs, PG-analog, LTs, and other lipoxygenase products on hearing and levels of AA metabolites in the perilymph were studied in chinchillas. Cyclooxygenase products, PGI2, 6-keto-PGF1 alpha, Iloprost (PGI2 analog), PGE2, and LTB4, LTC4, and 15-hydroxyeicosatetraenoic acid (15-HETE) in the lipoxygenase products in the dose of 150 ng were applied on the round window membrane (RWM); cochlear function tested by auditory brainstem response (ABR) and samples of perilymph were collected at 0.5, 1, 2, and 4 hours after the application. Samples of perilymph were assayed for all spectra of AA metabolites by high performance liquid chromatography (HPLC) and radioimmunoassay (RIA). PG-treated animals developed minimal or no hearing loss. LT-treated animals exhibited hearing loss of 20 to 40 dB, peaking at one hour after the treatment. Elevated levels of arachidonic acid metabolites were measured in the perilymph of the ears treated with respective AA metabolites, with peak levels at one hour from the application. The findings of this study indicate that hearing loss can be induced by altered levels of PGs or LTs in the perilymph. This is another strong evidence that salicylate induced ototoxicity can be mediated by abnormal arachidonic acid metabolism in the inner ear.

Animals↗