The etiology of external ear malformations and its relation to abnormalities of the middle ear, inner ear, and other organ systems.
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Abnormalities, Multiple↗
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The prognostic significance of the air volume in the middle ear for the tendency to recurrence of secretory middle ear condition.
The incidence of recurrence of secretory middle ear conditions (SMEC) in the course of the first 3 months after extrusion of a grommet was evaluated in 172 tubulated patients in relation to a number of background variables in a stepwise logistic regression analysis. The background variables were: treatment period, 3-month period (season) of extrusion, sex, age, air volume in the middle ear, diagnosis (unilateral/bilateral, suppurative/non-suppurative and consequently antibiotics), other treatment apart from a grommet (paracentesis and/or adenoidectomy), and a history of allergy. There was a definite correlation between the incidence of recurrence and the air volume in the middle ear, as determined by physical volume test, after correction for age, recurrences being most common in ears with a small middle ear volume. In addition, there was a relationship, but not as marked, between the incidence of recurrence and age after correction for the middle ear volume, recurrences being less common in older patients. None of the other background variables played a statistically significant role when correction was made for age and middle ear volume. It is recommended to practise an expectant therapeutic strategy in SMEC in order to eliminate cases with spontaneous remission. In the event of recurrence, a more liberal reinsertion of grommets is recommended for patients with small middle ear volumes, while in those with larger volumes a different aetiology should possibly be considered.
Adenoidectomy↗
Congenital malformations of the middle ear with an intact external ear: a review of 38 cases.
In patients with middle ear malformations, one can expect an improvement in hearing following ear surgery. Thus, it is crucial for the ear surgeon to have an increased awareness of this disease. For a better understanding of this condition, 38 patients who underwent ear surgery were studied. All patients had congenital ossicular malformations but with an intact external ear. On the basis of our intra-operative observations, 15 cases were assigned to group A (single malformation) and 23 cases to group B (multiple malformations). The pre-operative air-conduction threshold in group B patients was higher than that in group A. Pre-operatively in group A 2 out of 20 ears had mild, 17 had moderate and 1 had severe hearing loss (HL). In group B, out of 25 ears, 3 had mild, 13 had moderate and 9 had severe HL. Post-operatively in group A, 2 had normal hearing, 16 had mild, 2 had moderate and none had severe HL. In group B, postoperatively 1 had normal hearing, 18 had mild, 4 moderate and 2 severe HL. Therefore, in patients with multiple middle ear malformations, the surgeon should know that the prospect of an improvement in the hearing threshold is rather low even after surgical reconstruction.
Adolescent↗
Pressure transmission properties from the externa ear canal to the inner ear. An experimental study using guinea pigs.
The inner ear pressure (PIE) in response to pressure changes in the external ear canal was measured in guinea pigs while alternatively opening and closing the perforation of the otic bulla. When the bulla was opened, only a transient degree of applied pressure was transmitted to the inner ear and the amplitude of the PIE was smaller than that of the corresponding PIE when the bulla was closed. This was because the applied pressure was exclusively transmitted to the inner ear via the ossicular chain. When the otic bulla was closed, the pressure was transmitted not only via the ossicular chain but also via the round window (RW) through the middle ear cavity. When the bulla was closed, the amplitude of PIE was larger by a positive pressure load than by the corresponding negative one. The amplitude of PIE showed a linear relationship to ear canal pressure of at least within the +/- 200 mmH2O range, as long as pressure was slowly applied to the ear canal. When the loading pressure was abruptly changed, a bouncing response, possibly reflecting elasticity of the RW, was evoked, which diminished or disappeared when the round window was artificially ruptured.
Acoustic Impedance Tests↗
Toynbee Memorial Lecture 1997. Middle ear mechanics in normal, diseased and reconstructed ears.
A review of the structure-function relationships in normal, diseased and reconstructed middle ears is presented. Variables used to describe the system are sound pressure, volume velocity and acoustic impedance. We discuss the following: (1) Sound can be transmitted from the ear canal to the cochlea via two mechanisms: the tympanoossicular system (ossicular coupling) and direct acoustic stimulation of the oval and round windows (acoustic coupling). In the normal ear, middle-ear pressure gain, which is the result of ossicular coupling, is frequency-dependent and smaller than generally believed. Acoustic coupling is negligibly small in normal ears, but can play a significant role in some diseased and reconstructed ears. (2) The severity of conductive hearing loss due to middle-ear disease or after tympanoplasty surgery can be predicted by the degree to which ossicular coupling, acoustic coupling, and stapes-cochlear input impedance are compromised. Such analyses are used to explain the air-bone gaps associated with lesions such as ossicular interruption, ossicular fixation and tympanic membrane perforation. (3) With type IV and V tympanoplasty, hearing is determined solely by acoustic coupling. A quantitative analysis of structure-function relationships can both explain the wide range of observed post-operative hearing results and suggest surgical guidelines in order to optimize the post-operative results. (4) In tympanoplasty types I, II and III, the hearing result depends on the efficacy of the reconstructed tympanic membrane, the efficacy of the reconstructed ossicular chain and adequacy of middle-ear aeration. Currently, our knowledge of the mechanics of these three factors is incomplete. The mechanics of mastoidectomy and stapedectomy are also discussed.
Biomechanical Phenomena↗
The comparative anatomy of the pig middle ear cavity: a model for middle ear inflammation in the human?
This study was undertaken to develop a functional model of otitis media with effusion (OME) in the pig (Sus scrofa), with the purpose of investigating the origin of lymphocytes populating the middle ear during the course of an inflammatory process. The relevance of the model to the human condition of OME is to a large extent dependent on the anatomical and physiological similarities between the middle ear cavity and the pharyngeal lymphoid tissue of the pig and man. Anatomical specimens were collected from 7 young Large White pigs to determine the gross anatomy of the middle ear cavity and the histological characteristics of the middle ear mucosa. It was found that the anatomy of the 3 parts of the middle ear cavity in man and in the pig is broadly similar, although some minor differences were observed. The porcine eustachian tube was seen to be cartilaginous throughout its length in contrast to the part osseous, part cartilaginous structure found in man; the porcine ossicles were slightly different in shape to those of man and the air cell system was situated inferior to the tympanic cavity in the pig as opposed to posteriorly in man. This paper describes the structure and morphology of the pig middle ear cavity and compares and contrasts it with that of man. The minor differences observed are of anatomical importance but do not diminish the usefulness of the pig middle ear cleft as a potential model for human middle ear disorders.
Animals↗
Relationship between three inner ear antigens with different molecular weights and autoimmune inner ear disease.
Crude inner ear antigen (CIEAg) can induce autoimmune inner ear disease (AIED) although it is not known which subcomponent of CIEAg is involved. In this study, we investigated the relationship between 3 purified inner ear antigens (31, 42-45 and 60 kD proteins) and AIED, and determined their distribution in normal guinea pig cochlea. Three groups of guinea pigs were immunized with the three inner ear antigens and one group served as a control. The hearing thresholds, serum IgG level and morphological changes in the inner ear were observed. The expression of the three antigens in the cochlea was detected using immunohistochemical techniques. No obvious changes in hearing thresholds or inner ear morphology were observed between the control and 42-45 kD groups. Animals immunized with the 31 or 60 kD proteins showed a significant increase in hearing thresholds (p < 0.05 vs control), accompanied by morphological changes in the inner ear. The serum IgG level was increased significantly (p < 0.05) in all immunized animals. The 31 kD protein was distributed in the cochlear nerve and spiral ganglion, while the 42-45 and 60 kD proteins were distributed widely, being found in the spiral ganglion, organ of Corti, stria vascularis and spiral ligament. These results suggest that two subcomponents of CIEAg (the 31 and 60 kD proteins) may induce AIED independently, that several inner ear antigens may contribute to the pathogenesis of AIED and that the 31 kD protein is of high tissue specificity and may be used as a marker protein for the clinical diagnosis of AIED.
Animals↗
Assessment of ear length and low set ears in newborn infants.
In order to define normal values for ear length and position in the newborn infant, 198 (87 term and 111 preterm) infants were examined. In every case gestational age was determined chronologically and clinically. Ear length was measured from the superior to the inferior aspects of the ear. Using a horizontal line passing through the inner canthi of the eyes the portion of the ear above this line was measured, determining the position of the ear by its relation to total ear length. Normal values are presented by plotting the mean +/- 2 SD versus the gestational age. Small ears and low set ears are defined as values less than the mean -2 SD.
Ear↗
Effect of a middle ear immune response on inner ear antibody levels.
The effect of a middle ear immune response upon antibody levels in the perilymphatic compartment of the inner ear was investigated in the guinea pig. Animals were systemically sensitized with keyhole limpet hemocyanin (KLH) and bovine serum albumin (BSA) until high circulating levels were achieved. The middle ear cavity was then challenged with KLH, resulting in a vigorous immune response with effusion and mucosal inflammation. Antibody levels against KLH and BSA were then compared in serum, middle ear effusions, and perilymph. Anti-KLH levels in perilymph were found to increase substantially during middle ear response to challenge, while the anti-BSA levels did not, indicating a local origin for the anti-KLH antibody. The most likely explanations for these findings are inner ear antibody originated in the middle ear and diffused across the round window membrane, or antigen diffused across the round window membrane and evoked local production of antibody within the inner ear.
Animals↗
Do magnesium infusions protect the inner ear during middle ear surgery? A randomized double blind study.
Joachims et al. recently demonstrated that magnesium was able to protect the inner ear during exposure to noise and fire arms. During middle ear surgery, the inner ear is subjected to noise from fraising and drilling. We saw fit, therefore, to conduct a random double blind study to establish whether magnesium infusions would protect the inner ear during middle ear surgery. We examined 80 patients (38 verum, 42 placebo). The verum patients received 10 mg/kg body weight magnesium 12 hours and 1 hour prior to operation. Plasma and red cell magnesium levels were measured pre-operatively and intra-operatively; they rose as expected. Post-operative auditory tests showed that magnesium had no tendency to prevent inner ear damage. Advocates of magnesium criticize the limited number of patients in our study as well as the administration of the magnesium substitute. In our opinion, however, it should be borne in mind when evaluating these findings that noise from drilling and fraising is only one factor among many which can induce inner ear injury during middle ear surgery.
Adult↗
Change of guinea pig inner ear pressure by square wave middle ear cavity pressure variation.
The inner ear fluid pressure of guinea pigs was measured during square wave middle ear cavity pressure variation. Time constants were derived for the slopes of the inner ear pressure recovery curves after middle ear pressure change. A "single exponential" function did not fit well and therefore more complicated functions were used for this purpose. For middle ear pressure increasing from zero to a few centimetres of water, returning to zero again, decreasing from zero to minus a few centimetres of water and then returning to zero again, time constants for the inner ear pressure recovery curves were on average 15.0, 8.6, 2.5 and 2.5 s, respectively. The results could not be described using a linear model with constant window membrane compliance and cochlear aqueduct flow resistance. A possible explanation for the large difference in time constants for positive or negative middle ear pressure changes is a dependence on aqueduct flow resistance or round window membrane position.
Animals↗
Canal wall down tympanoplasty with canal reconstruction for middle-ear cholesteatoma: post-operative hearing, cholesteatoma recurrence, and status of re-aeration of reconstructed middle-ear cavity.
The post-operative outcome of hearing, the reconstructed external auditory canal, and the state of the reconstructed middle-ear cavity after canal wall down tympanoplasty with canal and attico-antrum reconstruction was studied in 103 ears with middle-ear cholesteatoma. The reconstructed mastoid cavity was re-aerated in 36.5 per cent of the cases, which was significantly lower than for the epitympanum (63.5 per cent) and tympanic cavity (82.4 per cent). Tympanoplasty was successful in terms of hearing results in 68.9 per cent of all subjects and in 75.4 per cent of the ears having a re-aerated tympanic cavity, which was significantly better than the 38.5 per cent for ears in which the tympanic cavity was not re-aerated. The findings of recurrent cholesteatoma, tympanic atelectasis, and tympanic effusion were observed with significantly (p<0.03) high incidence in ears with no re-aerated space in their reconstructed mastoid cavities. It was revealed that the post-operative outcome of this surgical technique was significantly related to the state of re-aeration of the reconstructed middle-ear cavity.
Adolescent↗
Ear drops for the removal of ear wax.
BACKGROUND: Problems attributed to the accumulation of wax (cerumen) are one of the most common reasons for people to present to their general practitioners with ear trouble (Sharp 1990). Treatment for this condition often involves use of a wax softening agent (cerumenolytic) in order to disperse the cerumen and reduce the need for syringing, or to facilitate syringing should it prove necessary, but there is no consensus on the effectiveness of the wide variety of cerumenolytics in use. OBJECTIVES: To assess the effectiveness of ear drops (cerumenolytics) for the removal of symptomatic ear wax. SEARCH STRATEGY: We searched the Cochrane ENT Group Register, the Cochrane Central Register of Controlled Trials (CENTRAL, Issue 1, 2003), and MEDLINE and EMBASE up to March 2003. Reference lists of all trials were also manually searched. SELECTION CRITERIA: We identified all randomised controlled trials (with or without blinding) in which a cerumenolytic was evaluated in comparison with either no treatment, a placebo, or other cerumenolytics in participants with hard or impacted ear wax, and in which the proportion of participants with sufficient clearance of the external canal to make further mechanical clearance unnecessary (primary outcome measure) was stated or calculable. The full text articles of all the retrieved trials of possible relevance were reviewed by the two reviewers and the inclusion criteria applied independently. Any differences in opinion about which studies to include in the review were resolved by discussion. DATA COLLECTION AND ANALYSIS: Trials were graded for methodological quality using the Cochrane approach. Data extraction was performed in a standardised manner by one reviewer and rechecked by the other reviewer, and where necessary investigators were contacted to obtain missing information. Meta-analysis was neither possible nor considered appropriate because of the heterogeneity of the treatments, treatment amounts and durations, trial procedures, and scoring systems. A narrative overview of the results is therefore presented. MAIN RESULTS: Eight trials satisfied the inclusion criteria, the majority of which were of poor quality. In all, 587 participants received one of nine different cerumenolytics. One trial compared active treatments with no treatment, two trials compared active treatments with water or a saline 'placebo', and all eight trials placed two or more active treatments in head-to-head comparisons. Seven trials included syringing as a secondary treatment where necessary.Overall, results were inconclusive. One trial found a significant difference between one of three active agents (Cerumol) in comparison to no treatment, but no statistically significant difference was found between these three agents (sodium bicarbonate ear drops; Cerumol; sterile water). In two trials no statistical difference was found between the effectiveness of either sodium bicarbonate ear drops, Cerumol, Cerumenex or Colace versus a sterile water or saline 'placebo'. Three trials (from the same source) found statistically significant differences in favour of the same active agent (Exterol) in comparison to glycerol and Cerumol. Three trials found no statistically significant difference between two or more cerumenolytics (Otocerol versus Cerumol; Audax versus Earex; sodium bicarbonate ear drops versus Cerumol). Two trials comparing the same two cerumenolytics (Cerumenex versus Colace) also failed to show any significant benefit of one over the other. No serious adverse effects were reported from any of the interventions. REVIEWER'S CONCLUSIONS: Trials to date have been heterogeneous and of poor quality, making it difficult to offer any definitive recommendations on the effectiveness of cerumenolytics for the removal of symptomatic ear wax. Future trials should be of high methodological quality, have large sample sizes, and compare both oil-based and water-based solvents with placebo and/or no treatment.
Carbamide Peroxide↗
FUM1--a gene required for fumonisin biosynthesis but not for maize ear rot and ear infection by Gibberella moniliformis in field tests.
We have analyzed the role of fumonisins in infection of maize (Zea mays) by Gibberella moniliformis (anamorph Fusarium verticillioides) in field tests in Illinois and Iowa, United States. Fumonisin-nonproducing mutants were obtained by disrupting FUM1 (previously FUM5), the gene encoding a polyketide synthase required for fumonisin biosynthesis. Maize ear rot, ear infection, and fumonisin contamination were assessed by silk-channel injection in 1999 and 2000 and also by spray application onto maize silks, injection into maize stalks, and application with maize seeds at planting in 1999. Ear rot was evaluated by visual assessment of whole ears and by calculating percentage of symptomatic kernels by weight. Fumonisin levels in kernels were determined by high-performance liquid chromatography. The presence of applied strains in kernels was determined by analysis of recovered isolates for genetic markers and fumonisin production. Two independent fumonisin-nonproducing (fum1-3 and fum1-4) mutants were similar to their respective fumonisin-producing (FUM1-1) progenitor strains in ability to cause ear rot following silk-channel injection and also were similar in ability to infect maize ears following application by all four methods tested. This evidence confirms that fumonisins are not required for G. moniliformis to cause maize ear rot and ear infection.
Fumonisins↗
Use of cartilage plate as tympanic membrane in total middle ear reconstructive surgery for infected radicalized ear.
OBJECTIVE: To evaluate the usefulness of cartilage plates as tympanic membranes combined with total middle ear reconstructive surgery for radicalized ears. STUDY DESIGN: Retrospective study between 1994 and 1999. SETTING: Tertiary care referral medical center. PATIENTS: Seven patients had seven ears with severe chronic otorrhea after radical mastoidectomy. All patients had severe to profound sensorineural hearing loss and expected a trouble-free ear rather than improved hearing after surgery. Patients were followed up for 4 years postoperatively. METHODS: After the middle ear space was cleaned, the tympanic membrane was reconstructed using a plate prepared from the tragal cartilage. The major part of the posterior wall was reconstructed using a conchal cartilage plate. Cortical bone segments were inserted to support the cartilage plate. RESULTS: Preoperatively, cultures of ear discharge were positive for various bacteria. Recovery with dry eardrums was noted in six patients, and one patient showed minimal erosion. No postoperative complications were encountered, but the hearing threshold did not improve postoperatively. CONCLUSIONS: Total middle ear reconstructive surgery is suitable for patients with chronic otorrhea complicating radical mastoidectomy. The use of cartilage plates seems to be clinically appropriate, particularly for patients with severe infection who expect a trouble-free ear rather than hearing gain after surgery.
Adult↗
A single-blind, randomized study to compare the efficacy of two ear drop preparations ('Audax' and 'Cerumol') in the softening of ear wax.
A parallel group, single-blind, randomized study was carried out in a general practice to compare the effectiveness and tolerability of two ear drop preparations ('Audax' and 'Cerumol') in the softening of ear wax in 50 adult patients with impacted or hardened ear wax. Assessments were made on entry of the amount, colour and consistency of the ear wax, symptoms, and objective hearing. Patients were then allocated at random to receive one or other preparation and instructed to use the drops, morning and evening, for 4 days after which they were reassessed. Details were recorded of any side-effects or discomfort caused by the study medication and both physician and patients were asked to give their overall opinion of treatment efficacy. Both treatments were shown to be effective in the softening of ear wax and were well tolerated, there being no significant difference between the two groups in these parameters. However, patients who had abnormal hearing before treatment had a significantly greater improvement in objective hearing after treatment with 'Audax' ear drops compared to those patients treated with 'Cerumol' ear drops. There were no between-treatment differences in either either the physician's or patient's overall assessments of effectiveness.
Adolescent↗
Ear-lobe crease and ear-canal hair as predictors of coronary artery disease in Indian population.
215 patients of different communities were selected randomly to predict the correlation between the ear-lobe crease, ear-canal hair and coronary artery disease. On analysis, it was found that prevalence of the ear-lobe crease increases with advancing age, and the incidence was much more higher in Sindhis in whom the overall incidence of CAD is also significantly high. Bilateral diagonal ear-lobe crease was found to be significantly (P less than 0.001) associated in patients with documented CAD, and a significant difference was also observed between men with and without CAD in the presence of ear-canal hair with age matched group. The combined presence of ear-lobe crease and ear-canal hair was more definite and more sensitive index of underlying CAD.
Adolescent↗
Classification of congenital middle ear anomalies. Report on 144 ears.
The surgical findings in 144 successive ears operated on for congenital conductive hearing loss were analyzed, and the results were evaluated in terms of hearing gain. All the patients underwent middle ear surgery at the University Hospital Nijmegen between 1964 and 1990. A classification system was developed to analyze the findings. Class 1 comprises ears with congenital isolated stapes ankylosis. Class 2 comprises ears with congenital stapes ankylosis in combination with a congenital anomaly of the ossicular chain. Class 3 comprises ears with congenital anomalies of the ossicular chain and at least a mobile stapes footplate. Class 4 comprises ears with aplasia or severe dysplasia of the oval window or round window.
Child↗